Home > Products > Valid Products > AFD

000
FXUS64 KBRO 250236 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
936 PM CDT FRI APR 24 2015

.DISCUSSION...SUPERCELL/MULTICELL CLUSTER ABOUT 40 MILES SOUTH OF
THE RIVER CONTINUES TO MOVE SLOWLY NORTHEASTWARD IN THE GENERAL
DIRECTION OF HIDALGO COUNTY. BROWNSVILLE SOUNDING SHOWS A STRONG
CAP BUT INCREASING SPEED DIVERGENCE APPEARS TO BE HOLDING THE
AIRMASS IN PLACE. WITH THE COMPLEX ADVECTION/PROPAGATION ISSUES OF
THIS COMPLEX AND THE INCREASINGLY STABLE AIRMASS IT WILL ENCOUNTER
AS IT MOVES EAST STILL NOT ENTIRELY CERTAIN IT WILL HOLD
TOGETHER...BUT TRENDS HAVE HELD WELL ENOUGH TO INCLUDE HIDALGO
COUNTY IN THE SEVERE THUNDERSTORM WATCH UNTIL 2 AM. LARGE
HAIL/DAMAGING WIND/FLASH FLOODING WILL ALL BE A RISK IF THE
CLUSTER HOLDS TOGETHER IN ITS CURRENT FORM AS IT CROSSES THE
RIVER. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 819 PM CDT FRI APR 24 2015/

DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 250236 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
936 PM CDT FRI APR 24 2015

.DISCUSSION...SUPERCELL/MULTICELL CLUSTER ABOUT 40 MILES SOUTH OF
THE RIVER CONTINUES TO MOVE SLOWLY NORTHEASTWARD IN THE GENERAL
DIRECTION OF HIDALGO COUNTY. BROWNSVILLE SOUNDING SHOWS A STRONG
CAP BUT INCREASING SPEED DIVERGENCE APPEARS TO BE HOLDING THE
AIRMASS IN PLACE. WITH THE COMPLEX ADVECTION/PROPAGATION ISSUES OF
THIS COMPLEX AND THE INCREASINGLY STABLE AIRMASS IT WILL ENCOUNTER
AS IT MOVES EAST STILL NOT ENTIRELY CERTAIN IT WILL HOLD
TOGETHER...BUT TRENDS HAVE HELD WELL ENOUGH TO INCLUDE HIDALGO
COUNTY IN THE SEVERE THUNDERSTORM WATCH UNTIL 2 AM. LARGE
HAIL/DAMAGING WIND/FLASH FLOODING WILL ALL BE A RISK IF THE
CLUSTER HOLDS TOGETHER IN ITS CURRENT FORM AS IT CROSSES THE
RIVER. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 819 PM CDT FRI APR 24 2015/

DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 250236 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
936 PM CDT FRI APR 24 2015

.DISCUSSION...SUPERCELL/MULTICELL CLUSTER ABOUT 40 MILES SOUTH OF
THE RIVER CONTINUES TO MOVE SLOWLY NORTHEASTWARD IN THE GENERAL
DIRECTION OF HIDALGO COUNTY. BROWNSVILLE SOUNDING SHOWS A STRONG
CAP BUT INCREASING SPEED DIVERGENCE APPEARS TO BE HOLDING THE
AIRMASS IN PLACE. WITH THE COMPLEX ADVECTION/PROPAGATION ISSUES OF
THIS COMPLEX AND THE INCREASINGLY STABLE AIRMASS IT WILL ENCOUNTER
AS IT MOVES EAST STILL NOT ENTIRELY CERTAIN IT WILL HOLD
TOGETHER...BUT TRENDS HAVE HELD WELL ENOUGH TO INCLUDE HIDALGO
COUNTY IN THE SEVERE THUNDERSTORM WATCH UNTIL 2 AM. LARGE
HAIL/DAMAGING WIND/FLASH FLOODING WILL ALL BE A RISK IF THE
CLUSTER HOLDS TOGETHER IN ITS CURRENT FORM AS IT CROSSES THE
RIVER. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 819 PM CDT FRI APR 24 2015/

DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 250236 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
936 PM CDT FRI APR 24 2015

.DISCUSSION...SUPERCELL/MULTICELL CLUSTER ABOUT 40 MILES SOUTH OF
THE RIVER CONTINUES TO MOVE SLOWLY NORTHEASTWARD IN THE GENERAL
DIRECTION OF HIDALGO COUNTY. BROWNSVILLE SOUNDING SHOWS A STRONG
CAP BUT INCREASING SPEED DIVERGENCE APPEARS TO BE HOLDING THE
AIRMASS IN PLACE. WITH THE COMPLEX ADVECTION/PROPAGATION ISSUES OF
THIS COMPLEX AND THE INCREASINGLY STABLE AIRMASS IT WILL ENCOUNTER
AS IT MOVES EAST STILL NOT ENTIRELY CERTAIN IT WILL HOLD
TOGETHER...BUT TRENDS HAVE HELD WELL ENOUGH TO INCLUDE HIDALGO
COUNTY IN THE SEVERE THUNDERSTORM WATCH UNTIL 2 AM. LARGE
HAIL/DAMAGING WIND/FLASH FLOODING WILL ALL BE A RISK IF THE
CLUSTER HOLDS TOGETHER IN ITS CURRENT FORM AS IT CROSSES THE
RIVER. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 819 PM CDT FRI APR 24 2015/

DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 250119 AAC
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
819 PM CDT FRI APR 24 2015

.DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 250119 AAC
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
819 PM CDT FRI APR 24 2015

.DISCUSSION...INITIAL STORM CLUSTER THAT HAS PUSHED INTO ZAPATA
COUNTY APPEARS TO NOT QUITE BE UTILIZING THE FULL INSTABILITY THAT
IS PRESENT THROUGH THE COLUMN AND HAS CONTINUED TO STRUGGLE AS IT
CROSSES THE RIVER. THE LOW CONVERGENCE INVOF THE CELL WILL BE A
FOCUS FOR CONTINUED DEVELOPMENT BUT MAY STRUGGLE AGAINST CAPPING
THAT APPEARS TO INCREASE AS YOU MOVE FROM WEST TO EAST IN THE CWA.

IN HOUSE LAPS/RAP13 SEEM TO HAVE A GOOD HANDLE ON OUR CURRENT
THERMODYNAMIC ENVIRONMENT WHEN COUPLED WITH THE 00Z BROWNSVILLE
SOUNDING. VERY STRONG CAPPING IS EVIDENT ON THE SOUNDING THAT GETS
A LITTLE LESS AS YOU MOVE WESTWARD. THE CAPPING IS BELOW
PARTICULARLY STEEP MID LEVEL LAPSE RATES OF AROUND 8 DEGREES C/KM
SO IF AN UPDRAFT CAN GET INTO THAT LAYER IT COULD BE QUITE
INTENSE.

WATER VAPOR/GFS UPPER AIR ANALYSIS SUGGEST AN INCREASE IN UPPER
DIVERGENCE OVER THE NEXT 3 TO 4 HOURS WHICH WILL INCREASE LOW
LEVEL CONVERGENCE AND WORK ON THE CAP A BIT. RAP13 SUGGESTS IT
WILL BE COMPLETELY LIFTED OUT ALTHOUGH THAT SEEMS UNLIKELY GIVEN
THE SOMEWHAT MODEST AMOUNT OF LIFT THAT WILL BE PRODUCED.

SATELLITE/RADAR TRENDS DO HOWEVER SHOW A LITTLE STRONGER LINE OF
CONVECTION ABOUT 120 MILES WEST OF BROWNSVILLE WITH INCREASED
LIGHTNING ACTIVITY OVER THE LAST 15 TO 30 MINUTES. IF THAT AREA WERE
TO HOLD TOGETHER WOULD BE COLLOCATED WITH IMPROVED LARGE SCALE
ASCENT UPON ARRIVAL AND WOULD LIKELY STILL HAVE A VERY UNSTABLE
BOUNDARY LAYER TO WORK WITH SO WILL KEEP THE GUARD UP FOR THE NEXT
FEW HOURS. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 701 PM CDT FRI APR 24 2015/

DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 250001 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
701 PM CDT FRI APR 24 2015

.DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 250001 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
701 PM CDT FRI APR 24 2015

.DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 250001 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
701 PM CDT FRI APR 24 2015

.DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 250001 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
701 PM CDT FRI APR 24 2015

.DISCUSSION...ALL PRODUCTS UPDATED FOR SVR WATCH 104. CURRENTLY
WATCHING THE LONE SUPERCELL CANDIDATE ABOUT 40 MILES SOUTHWEST OF
FALCON LAKE WITH LESS INTENSE CONVECTION BEHIND IT. ATMOSPHERE
REMAINS ESPECIALLY UNSTABLE WITH GOOD SHEAR SO LIKELY THAT
CELL...PERHAPS WITH A FEW ADJACENT STRONG/SEVERE CELLS WILL BEGIN
TO MARCH INTO THE AREA BY ABOUT 8 PM. LOW LAYER SHEAR IS NOT
ESPECIALLY FAVORABLE FOR STRONG/LONG TRACK TORNADOES BUT THE
SUPERCELLULAR NATURE OF THE CONVECTION MAKES A TORNADO OR TWO AT
LEAST A POSSIBILITY THROUGH THE EARLY EVENING. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 641 PM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 242341
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 242341
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 242341
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61




000
FXUS64 KBRO 242341
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CONDITIONAL CONVECTIVE THREAT WILL BE THE HEADLINE IN
THE NEXT FEW HOURS. STRONG TO SEVERE CONVECTION IS ATTEMPTING TO
FIRE OVER MEXICO AND THE ENVIRONMENT IS FAVORABLE FOR STRONG TO
SEVERE STORMS IF THEY ARE ABLE TO INITIATE AND SUSTAIN AND MAY
UPSCALE INTO A RELATIVELY LARGE COMPLEX IN THE VERY HUMID/UNSTABLE
ENVIRONMENT. OTHERWISE PREVAILING MVFR IS EXPECTED TO DETERIORATE
TO IFR BY A LITTLE BEFORE SUNRISE. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 529 PM CDT FRI APR 24 2015/

DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/61





000
FXUS64 KBRO 242237 CCA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
529 PM CDT FRI APR 24 2015

.DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/60





000
FXUS64 KBRO 242237 CCA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
529 PM CDT FRI APR 24 2015

.DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 70S. DEEP LAYER SHEAR IS ALSO FAVORABLE WITH
LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A STURDY CAP
REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG SOUTHWESTERLY
WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR CONVECTION IF
SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF FAVORABLE SPEED
SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END OF A BROADER JET
MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE SUFFICIENT TO
INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE SIERRA MADRE
MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT SCATTERED CELLS
UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS AND MOVING ACROSS
THE AREA. THE END OF DAYTIME HEATING SHOULD LIMIT THE SEVERE WEATHER
RISK EASTWARD SOMEWHAT BUT IT IS DIFFICULT TO ESTIMATE IF IT WILL BE
QUICK ENOUGH TO EXCLUDE SOME OR ALL OF THE RGV METRO AREAS IF
CONVECTION INITIATES. IR/RADAR/LIGHTNING TRENDS IN THE AREA ARE
UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD PROVIDES FURTHER DETAIL ON
OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/60




000
FXUS64 KBRO 242229 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
529 PM CDT FRI APR 24 2015

.DISCUSSION...CONTINUING TO MONITOR SVR WX THREAT CLOSELY THIS
EVENING. 22Z MODIFIED LAPS/RAP SOUNDINGS YIELD EXTREME INSTABILITY
WITH EVEN 100MB MLCAPE VALUES OF 3000 TO 3500 J/KG WITH SURFACE
DEWPOINTS IN THE UPPER 80S. DEEP LAYER SHEAR IS ALSO FAVORABLE
WITH LOW LAYER SHEAR THAT IS WEAK...BUT VEERS WITH HEIGHT. A
STURDY CAP REMAINS IN PLACE OVER THE AREA...REINFORCED BY STRONG
SOUTHWESTERLY WINDS ALOFT...BUT SHOULD BE THIN ENOUGH TO ALLOW FOR
CONVECTION IF SOME MID LEVEL ASCENT CAN GET GOING. AN AREA OF
FAVORABLE SPEED SHEAR IS APPROACHING FROM MEXICO AT THE SOUTH END
OF A BROADER JET MAX THAT IS FOCUSED OVER TEXAS...AND THAT MAY BE
SUFFICIENT TO INITIATE MORE CONVECTION IN THE IMMEDIATE LEE OF THE
SIERRA MADRE MOUNTAINS THIS AFTERNOON. HRRR/RAP/NAM SUPPORT
SCATTERED CELLS UPSCALING INTO AN MCS/LEWP OVER THE NEXT FEW HOURS
AND MOVING ACROSS THE AREA. THE END OF DAYTIME HEATING SHOULD
LIMIT THE SEVERE WEATHER RISK EASTWARD SOMEWHAT BUT IT IS
DIFFICULT TO ESTIMATE IF IT WILL BE QUICK ENOUGH TO EXCLUDE SOME
OR ALL OF THE RGV METRO AREAS IF CONVECTION INITIATES. IR/RADAR/LIGHTNING
TRENDS IN THE AREA ARE UP...BUT YET TO BE EXPLOSIVE. SPC SWOMCD
PROVIDES FURTHER DETAIL ON OUR NEAR TERM CONVECTIVE SITUATION.

UPDATED GRIDS TO INCLUDE SEVERE WORDING OVER A LARGER PORTION OF
THE AREA AND WILL BE BEEFING UP THE HWO SLIGHTLY IN THE NEXT FEW
MINUTES. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 255 PM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  50  20  10  10
BROWNSVILLE          78  88  77  88 /  50  20  10  10
HARLINGEN            77  90  77  91 /  50  20  10  10
MCALLEN              76  93  77  95 /  50  20  10  10
RIO GRANDE CITY      75  92  76  97 /  60  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

68/60





000
FXUS64 KBRO 241955
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
255 PM CDT FRI APR 24 2015

.SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

.LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

&&

.MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  40  20  10  10
BROWNSVILLE          78  88  77  88 /  40  20  10  10
HARLINGEN            77  90  77  91 /  40  20  10  10
MCALLEN              76  93  77  95 /  40  20  10  10
RIO GRANDE CITY      75  92  76  97 /  50  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/54/59




000
FXUS64 KBRO 241955
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
255 PM CDT FRI APR 24 2015

.SHORT TERM /NOW THROUGH SATURDAY NIGHT/...H5 TROUGH PROGRESSING
NEWD THROUGH NM CURRENTLY...WITH STRONG MIDLEVEL FLOW WRAPPING
AROUND IT OVERHEAD. INSTABILITY ALOFT IS PEAKING THIS EVENING...
WITH DECENT CAPE VALUES STILL FORECAST ESPECIALLY OUT WEST.
MRNG BRO SOUNDING STILL SHOWED SIGNIFICANT CAPPING INVERSION...
BUT MORE REPRESENTATIVE INLAND SOUNDING FROM DRT SHOWED MINIMAL
CAP AND LOWER CONVECTIVE TEMPERATURE. GOOD CU BUBBLING NOTED TO
THE SOUTHWEST IN MAIN THREAT AREA...SO GOOD CHANCES FOR TSTMS
STILL REMAINS IN THE FORECAST FOR THIS EVENING...ESPECIALLY WEST
OF US281. MOST MODELS LOOK TO BE STARTING THE CONVECTION AS
CELLULAR BEFORE MORPHING INTO A BROKEN SQUALL LINE AS IT CROSSES
SOUTH TEXAS. MOST MODELS DO HAVE EVERYTHING THROUGH THE VALLEY BY
JUST AFTER MIDNIGHT...SO HAVE FOCUSED BIGGEST THREATS DURING THE
SUNSET TO MIDNIGHT. SATURDAY WILL BE THE BRIEF STABILIZATION
BEHIND THE OVERNIGHT THUNDERSTORMS...SO DAYTIME CONVECTION WILL BE
LOWER. TEMPERATURES WILL BE SIMILAR TO TODAY...WITH HIGHS A FEW
DEGREES EITHER SIDE OF 90 AND TD VALUES AROUND 75. THIS EQUATES TO
HEAT INDEX VALUES OF 100 TO 105 IN THE AFTERNOON. THUNDERSTORM
CHANCES SATURDAY WILL HINGE ON THE ABILITY OF THE DRYLINE TO PUSH
EASTWARD INTO THE WESTERN VALLEY IN THE EVENING. THIS SCENARIO
LOOKING MORE UNLIKELY WITH STEERING FLOW STILL FROM THE SW...SO
RAIN CHANCES REMAIN LOW SATURDAY INTO SATURDAY NIGHT.

.LONG TERM /SUNDAY THROUGH THURSDAY/...A FLAT PRESSURE FIELD WITH
LIGHT SOUTH WINDS AND CONTINUED MOIST LOW LEVEL AIR WILL GREET
RESIDENTS SUNDAY MORNING. THERE MAY BE A FEW LINGERING SHOWERS FROM
SATURDAY NIGHT STILL MOVING INTO OR OVER THE MID AND UPPER VALLEY. A
MID LEVEL SHORT WAVE WILL BE OVER THE FOUR CORNERS AND MOVING EAST
TOWARD NORTH TEXAS. SUNDAY HIGH TEMPS WILL HIT THE LOWER 90S ACROSS
MUCH OF THE AREA EXCEPT FOR THE IMMEDIATE COAST. A PUSH OF DRIER AIR
WILL ENTER THE UPPER VALLEY BY AFTERNOON BUT WILL MOST LIKELY NOT
MAKE IT TO THE COAST...WHICH WILL REMAIN ENSCONCED WITH HIGHER DEW
POINT AIR. A FEW SHOWERS OR THUNDERSTORMS MAY POP UP ALONG THE
BOUNDARY OVER THE HILL COUNTRY AND EXTEND SOUTH THROUGH THE COASTAL
BEND AND RIO GRANDE PLAINS...AS CYCLOGENESIS OCCURS OVER NORTH
CENTRAL TEXAS...AND ESPECIALLY AS MID LEVEL ENERGY MAY BE PRESENT...
WITH CONVECTION TOUCHING THE NORTH AND NORTHEAST PARTS OF THE CWA
LATER ON SUNDAY. LOW TEMPS WILL BE IN THE 70S ONCE MORE SUNDAY NIGHT
AS SOME CONVECTION HANGS ON TO THE NORTH.

AT THIS POINT...MONDAY THROUGH MID WEEK...THE FORECAST BECOMES A
LITTLE MORE COMPLEX...WITH DETAILS MORE DIFFICULT TO SUSS OUT. AT
FIRST LOOK...THE LONG RANGE MODELS ARE NOT TOO DIFFERENT AND A
CONSENSUS SHOULD BE ACCEPTABLE. A WEAK INITIAL FRONT WILL PUSH INTO
THE RIO GRANDE PLAINS AND EVEN THE UPPER VALLEY EARLY MON MORNING.
HIGH TEMPS WILL BE MILDER...IN THE MID 80S. SOME CONVECTION MAY
CONTINUE ACROSS THE NORTH AND THEN NORTHEAST THROUGH THE DAY AS THE
FRONT PULLS TO THE NORTHEAST. SOME CLEARING AND DRIER AIR MONDAY
NIGHT WILL LEAD TO OVERNIGHT LOWS IN THE 60S AND 70S.

THE MAIN SECONDARY FRONT WILL ARRIVE TUESDAY MORNING...BUT THE
EXTREME LOWER VALLEY MAY NOT CLEAR COMPLETELY UNTIL LATER IN THE
DAY. NORTH WINDS WILL INCREASE TO MODERATE OR BREEZY DURING THE DAY
WITH HIGHS AROUND 80. DID LEAN MORE TOWARD THE ECMWF ON WINDS FOR
THE DAY AS IT WAS A LITTLE STRONGER THAN THE GFS AND DIDN`T WANT TO
COME UP SHORT AT THIS POINT. THE H5 PATTERN WILL SLOWLY VEER AS THE
UPPER TROUGH EJECT  OVER OKLAHOMA AND UPSTREAM RIDGING BEGINS TO
PLAY A BIGGER ROLE. NIGHT TIME LOWS WILL DECREASE FURTHER TO THE
UPPER 50S AND LOWER 60S.

HIGH PRESSURE WILL SETTLE OVER NORTH TEXAS ON WEDNESDAY WITH FINE
WEATHER CONDITIONS. MILDER TEMPS AND SUNNIER SKIES WILL PREVAIL
THROUGH THURSDAY.

&&

.MARINE...
NOW THROUGH SATURDAY NIGHT...WINDS HAVE VARIED CONSIDERABLY
ACROSS THE GULF WATERS...WITH 15G20KTS ALONG TEH COAST...WHILE
BEYOND 30NM WINDS ARE ONLY AROUND 5KTS. WINDS SHOULD EVEN OUT
OVERNIGHT...AROUND 10KTS ALL LOCATIONS. SEAS WILL REMAIN RIGHT
AROUND 3 FT TONIGHT...WITH A SLIGHT INCREASE TO NEAR 4 FEET LATE
TOMORROW. NOT EXPECTING ANY AADVISORIES THROUGH THE NEXT 36
HOURS. A SQUALL LINE IS EXPECTED TO REACH THE GULF WATERS LATER
TONIGHT... WHICH WOULD BRING DOWNPOURS...VARIABLY GUSTY WINDS AND
FREQUENT LIGHTNING AS IT PASSES.

SUNDAY THROUGH TUESDAY...A WEAK PRESSURE GRADIENT OVER THE NORTHWEST
GULF WILL RESULT IN LIGHT SOUTHEAST WINDS AND LOW SEAS INITIALLY.
WINDS WILL INCREASE TO MODERATE SUNDAY AS A SURFACE TROUGH DEVELOPS
NEAR THE BIG BEND...TIGHTENING THE GRADIENT. AS THE TROUGH SHIFTS
TOWARD THE COAST SUNDAY NIGHT...WINDS WILL AGAIN DECREASE. LIGHT
WINDS WILL BECOME VARIABLE AS HIGH PRESSURE APPROACHES FROM UPSTREAM
MONDAY AND MONDAY NIGHT. NORTH WINDS WILL INCREASE AFTER A FRONTAL
PASSAGE TUESDAY MORNING...BECOMING MODERATE AND THEN STRONG BY TUE
AFTERNOON...WHEN SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP. A FEW
SHOWERS WILL BE POSSIBLE TUE DURING THE DAY. WAVE HEIGHTS WILL THEN
BUILD TOWARD SEVEN FT TUESDAY NIGHT. CONDITIONS WILL SLOWLY IMPROVE
ON WEDNESDAY AS HIGH PRESSURE BEHIND THE FRONT SPREADS OVER THE
AREA.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  86  77  84 /  40  20  10  10
BROWNSVILLE          78  88  77  88 /  40  20  10  10
HARLINGEN            77  90  77  91 /  40  20  10  10
MCALLEN              76  93  77  95 /  40  20  10  10
RIO GRANDE CITY      75  92  76  97 /  50  20  10  10
SOUTH PADRE ISLAND   77  84  77  79 /  40  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/54/59





000
FXUS64 KBRO 241743 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1243 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOWEST CLOUD DECK HAS TRIED TO ERODE THIS
MORNING...BUT IS STILL BKN025 AT KMFE. LOW DECK SHOULD CONTINUE TO
THIN THROUGH THE AFTERNOON...WHILE THE DENSE MIDLEVEL LAYER
CONTINUES TO OVERSPREAD THE REGION. WINDS HAVE BEEN GUSTY AT KBRO
WITH GUSTS IN THE UPPER 20S...WHILE KMFE HAS BARELY HAD WINDS
REACHING 10KTS. THINK WINDS WILL PICK UP SOME AT KMFE LATER THIS
AFTERNOON...BUT NO HIGHER THAN 15KTS. ORGANIZED SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED AGAIN TONIGHT...ESPECIALLY
CLOSER TO KMFE AND NORTH AND WEST. HAVE ADDED VCSH FOR MIDNIGHT
AND LATER FOR KMFE SINCE TIMING IS STILL AN ISSUE...AND WOULD BE
LATER IN THE NIGHT IF AT ALL FOR KBRO AND KHRL. OVERNIGHT CIGS
WILL AGAIN LOWER...WITH CIGS AROUND 800 FT A GOOD MATCH FOR THE
PAST COUPLE NIGHTS. CIGS WILL DISSIPATE SLOWLY AGAIN TOMORROW WITH
VFR CONDITIONS IN THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 630 AM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.

PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/64





000
FXUS64 KBRO 241743 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1243 PM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOWEST CLOUD DECK HAS TRIED TO ERODE THIS
MORNING...BUT IS STILL BKN025 AT KMFE. LOW DECK SHOULD CONTINUE TO
THIN THROUGH THE AFTERNOON...WHILE THE DENSE MIDLEVEL LAYER
CONTINUES TO OVERSPREAD THE REGION. WINDS HAVE BEEN GUSTY AT KBRO
WITH GUSTS IN THE UPPER 20S...WHILE KMFE HAS BARELY HAD WINDS
REACHING 10KTS. THINK WINDS WILL PICK UP SOME AT KMFE LATER THIS
AFTERNOON...BUT NO HIGHER THAN 15KTS. ORGANIZED SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED AGAIN TONIGHT...ESPECIALLY
CLOSER TO KMFE AND NORTH AND WEST. HAVE ADDED VCSH FOR MIDNIGHT
AND LATER FOR KMFE SINCE TIMING IS STILL AN ISSUE...AND WOULD BE
LATER IN THE NIGHT IF AT ALL FOR KBRO AND KHRL. OVERNIGHT CIGS
WILL AGAIN LOWER...WITH CIGS AROUND 800 FT A GOOD MATCH FOR THE
PAST COUPLE NIGHTS. CIGS WILL DISSIPATE SLOWLY AGAIN TOMORROW WITH
VFR CONDITIONS IN THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 630 AM CDT FRI APR 24 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.

PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/64




000
FXUS64 KBRO 241130 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
630 AM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.
&&

.PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV




000
FXUS64 KBRO 241130 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
630 AM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.
&&

.PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV





000
FXUS64 KBRO 241130 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
630 AM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.
&&

.PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV





000
FXUS64 KBRO 241130 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
630 AM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...LIFR CONDITIONS ARE IN EFFECT AT THE BRO AERODROME
WITH HRL AND MFE ONLY SLIGHTLY BETTER. KBRO DOPPLER RADAR SHOWS
RAPIDLY DISSIPATING LIGHT RAIN MOVING ACROSS THE RIO GRANDE RIVER
RIGHT NOW...BRINGING AN END TO THE CONVECTION THAT RAGED JUST A
FEW HOURS AGO. VFR IS EXPECTED TO PREVAIL TODAY WITH MODERATE
WINDS AND RISING CEILINGS. DEGRADED AVIATION CONDITIONS ARE
ANTICIPATED TONIGHT WITH LIGHT FOG FORMATION FORECAST AND
DIMINISHING SURFACE WINDS. CONVECTION IS EXPECTED TO REMAIN OVER
THE WESTERN PORTION OF DEEP SOUTH TEXAS TONIGHT AND AWAY FROM THE
AERODROMES...BUT THIS WILL HAVE TO BE CLOSELY WATCHED...ESPECIALLY
FOR AERODROME MFE.
&&

.PREV DISCUSSION... /ISSUED 441 AM CDT FRI APR 24 2015/

SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV




000
FXUS64 KBRO 240941
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
441 AM CDT FRI APR 24 2015

.SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

&&

.MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  89  77  86  76 /  20  20  20  10
BROWNSVILLE          90  78  90  76 /  20  20  20  10
HARLINGEN            91  77  92  76 /  20  20  20  10
MCALLEN              93  76  93  76 /  20  40  20  10
RIO GRANDE CITY      94  75  95  75 /  20  50  20  10
SOUTH PADRE ISLAND   86  77  81  76 /  20  20  20  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

SHORT TERM...TOMASELLI-66
LONG TERM...CACERES-63
MESO/WX4PPT...BILLINGS-58





000
FXUS64 KBRO 240941
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
441 AM CDT FRI APR 24 2015

.SHORT TERM /NOW THROUGH SATURDAY/...KBRO DOPPLER RADAR NOTES
STRATIFORM RAINFALL WITH A FEW EMBEDDED THUNDERSTORMS MAINLY ALONG
AND EAST OF THE HIGHWAY 281/INTERSTATE 69C CORRIDOR RIGHT NOW.

TODAY...CONVECTION FROM THURSDAY NIGHT/EARLY FRIDAY MORNING WILL
HAVE STABILIZED THE ATMOSPHERE...HOWEVER THE INTRUSION OF A 500 MB
TROUGH INTO THE NEIGHBORING STATES OF NUEVO LEON...COAHUILA...AND
TAMAULIPAS WILL ALLOW FOR ISOLATED CONVECTION FOR THE DAYLIGHT
HOURS. TEMPERATURES IN THE UPPER 80S TO LOW 90S WERE REALIZED ON
THURSDAY...THEREFORE SIMILAR HIGH TEMPERATURES SHOULD BE
EXPERIENCED AGAIN FOR THIS DAY.

TONIGHT...MODELS INDICATE ANOTHER ROUND OF CONVECTION OFF THE HIGH
TERRAIN OF MEXICO DUE TO THE PASSAGE OF THE AFOREMENTIONED 500 MB
TROUGH. STORM PREDICTION CENTER HAS ENTIRE BRO CWFA IN A GENERAL
RISK OF THUNDERSTORMS...SO WILL NOT MENTION SEVERE THUNDERSTORMS IN
THE OFFICIAL FORTHCOMING ZONE FORECAST. HOWEVER...GIVEN THE NEAR
MISS WITH SEVERE WEATHER THURSDAY NIGHT/EARLY FRIDAY MORNING... THIS
ASPECT OF THE FORECAST WILL NEED TO MONITORED CAREFULLY BY
FORTHCOMING SHIFTS.

SATURDAY...DISSIPATION OF THE FRIDAY NIGHT MESOSCALE CONVECTIVE
COMPLEX SHOULD LEAVE ONLY A SLIGHT RISK OF CONVECTION FOR THE FIRST
HALF OF THE WEEKEND...AIDED BY THE APPROACH OF YET ANOTHER WEAK 500
MB TROUGH. HIGH TEMPERATURES SIMILAR TO FRIDAY ARE ANTICIPATED.

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...DRIER CONDITIONS
EXPECTED ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY. WILL
MENTION SLIGHT CHANCE POPS ACROSS THE EASTERN PORTIONS OVER THE
AREA FOR CONVECTION MOVING DOWN FROM THE COASTAL PLAINS SUNDAY.
CONVECTION TO OUR NORTH...OVER THE COASTAL BEND AND RIO GRANDE
PLAINS...SUNDAY NIGHT INTO MONDAY MAY DRIFT INTO THE NORTHERN
RANCHLANDS AND COASTAL COUNTIES. WILL CONTINUE TO MENTION SLIGHT
CHANCE POPS WITH CHANCE POPS OVER THE LOWER TEXAS COASTAL WATERS
ON MONDAY. WINDS SHIFTS TO NORTHWEST ON MONDAY...WITH THE PASSAGE
OF A PREFRONTAL TROUGH...DRIER AIR COULD FILTER INTO THE AREA BY
LATE MONDAY AFTERNOON BEFORE A COLD FRONT ARRIVES ON TUESDAY.
WELL ABOVE NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE
NORMAL IN THE WAKE OF THE FRONTAL PASSAGE. DRY CONDITIONS WILL
PREVAIL ACROSS DEEP SOUTH TEXAS WEDNESDAY AND THURSDAY.

&&

.MARINE...NOW THROUGH SATURDAY... BUOY 42020 REPORTED SOUTH WINDS
AROUND 6 KNOTS GUSTING TO AROUND 10 KNOTS WITH SEAS SLIGHTLY OVER
1.5 FEET WITH A PERIOD OF 6 SECONDS AT 03 CDT/08 UTC. MODERATE WINDS
AND SEAS WILL PREVAIL THROUGH A MAJORITY OF THE FORECAST PERIOD WITH
SURFACE HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO.
HOWEVER...A WEAK BOUNDARY AT THE SURFACE MAY CAUSE A TEMPORARY
INCREASE IN WINDS AND BUILDING OF SEAS TONIGHT...RESULTING IN A
SMALL CRAFT EXERCISE CAUTION FOR THE LOWER TEXAS COAST GULF OF
MEXICO WATERS.

SATURDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE OVER THE WESTERN
GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE WINDS AND MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST. SMALL CRAFT
ADVISORIES MAY BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER
WINDS AND HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A
COLD FRONT.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  89  77  86  76 /  20  20  20  10
BROWNSVILLE          90  78  90  76 /  20  20  20  10
HARLINGEN            91  77  92  76 /  20  20  20  10
MCALLEN              93  76  93  76 /  20  40  20  10
RIO GRANDE CITY      94  75  95  75 /  20  50  20  10
SOUTH PADRE ISLAND   86  77  81  76 /  20  20  20  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

SHORT TERM...TOMASELLI-66
LONG TERM...CACERES-63
MESO/WX4PPT...BILLINGS-58




000
FXUS64 KBRO 240520 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1220 AM CDT FRI APR 24 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...LARGE CLUSTERS OF SHOWERS AND THUNDERSTORMS CONTINUE
TO FIRE OVER NEIGHBORING MEXICO. RECENT TRACKS OF THE CONVECTION
SUGGEST THAT IT WILL MISS THE BRO/HRL AERODROMES...BUT MAY IMPACT
MFE WITHIN THE NEXT COUPLE OF HOURS. OTHERWISE...THE PREVIOUS
ISSUANCE OF TAFS WAS LARGELY RETAINED. TAFS WILL BE CLOSELY
MONITORED THROUGH THE NEXT FEW HOURS DUE TO THE CONVECTION NEARBY.
&&

.PREV DISCUSSION... /ISSUED 1012 PM CDT THU APR 23 2015/

DISCUSSION...WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS
THE UPPER VALLEY INTO ZAPATA COUNTY AS WELL AS ISOLATED SHOWERS
POPPING UP ACROSS THE MIDDLE VALLEY AND NORTHERN RANCHLANDS.
ANOTHER COMPLEX IS WELL SOUTH OF THIS AREA IN NEUVO LEON MOVING
NORTHEAST. AREAS OF SHOWERS AND THUNDERSTORMS ARE AIDED BY A UPPER
SPEED MAX AND MUCAPE OF 3500 J/KG AS SAMPLED BY 00Z BRO SOUNDING.

UPDATED THE GRIDS THROUGH 12Z...RAISING POPS ACROSS THE BOARD
WITH 30S IN THE LOWER VALLEY TO 70S OUT WEST WHERE CONVECTION IS
ONGOING. ALSO ADDED PATCHY FOG ALONG THE COAST AND COASTAL WATERS
AS 4-5 STATUTE MILE VISIBILITIES ARE BEING REPORTED IN THE COASTAL
WATERS AND ALSO THROUGH BEACH WEBCAMS. ONLY SLIGHT MASSAGING TO
TEMPERATURE AND WIND GRIDS NEEDED. UPDATE SENT.

PREV DISCUSSION... /ISSUED 636 PM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV




000
FXUS64 KBRO 240312
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1012 PM CDT THU APR 23 2015

.DISCUSSION...WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS
THE UPPER VALLEY INTO ZAPATA COUNTY AS WELL AS ISOLATED SHOWERS
POPPING UP ACROSS THE MIDDLE VALLEY AND NORTHERN RANCHLANDS.
ANOTHER COMPLEX IS WELL SOUTH OF THIS AREA IN NEUVO LEON MOVING
NORTHEAST. AREAS OF SHOWERS AND THUNDERSTORMS ARE AIDED BY A UPPER
SPEED MAX AND MUCAPE OF 3500 J/KG AS SAMPLED BY 00Z BRO SOUNDING.

UPDATED THE GRIDS THROUGH 12Z...RAISING POPS ACROSS THE BOARD
WITH 30S IN THE LOWER VALLEY TO 70S OUT WEST WHERE CONVECTION IS
ONGOING. ALSO ADDED PATCHY FOG ALONG THE COAST AND COASTAL WATERS
AS 4-5 STATUTE MILE VISIBILITIES ARE BEING REPORTED IN THE COASTAL
WATERS AND ALSO THROUGH BEACH WEBCAMS. ONLY SLIGHT MASSAGING TO
TEMPERATURE AND WIND GRIDS NEEDED. UPDATE SENT.

&&

.PREV DISCUSSION... /ISSUED 636 PM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




000
FXUS64 KBRO 240312
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1012 PM CDT THU APR 23 2015

.DISCUSSION...WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS
THE UPPER VALLEY INTO ZAPATA COUNTY AS WELL AS ISOLATED SHOWERS
POPPING UP ACROSS THE MIDDLE VALLEY AND NORTHERN RANCHLANDS.
ANOTHER COMPLEX IS WELL SOUTH OF THIS AREA IN NEUVO LEON MOVING
NORTHEAST. AREAS OF SHOWERS AND THUNDERSTORMS ARE AIDED BY A UPPER
SPEED MAX AND MUCAPE OF 3500 J/KG AS SAMPLED BY 00Z BRO SOUNDING.

UPDATED THE GRIDS THROUGH 12Z...RAISING POPS ACROSS THE BOARD
WITH 30S IN THE LOWER VALLEY TO 70S OUT WEST WHERE CONVECTION IS
ONGOING. ALSO ADDED PATCHY FOG ALONG THE COAST AND COASTAL WATERS
AS 4-5 STATUTE MILE VISIBILITIES ARE BEING REPORTED IN THE COASTAL
WATERS AND ALSO THROUGH BEACH WEBCAMS. ONLY SLIGHT MASSAGING TO
TEMPERATURE AND WIND GRIDS NEEDED. UPDATE SENT.

&&

.PREV DISCUSSION... /ISSUED 636 PM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




000
FXUS64 KBRO 240312
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1012 PM CDT THU APR 23 2015

.DISCUSSION...WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS
THE UPPER VALLEY INTO ZAPATA COUNTY AS WELL AS ISOLATED SHOWERS
POPPING UP ACROSS THE MIDDLE VALLEY AND NORTHERN RANCHLANDS.
ANOTHER COMPLEX IS WELL SOUTH OF THIS AREA IN NEUVO LEON MOVING
NORTHEAST. AREAS OF SHOWERS AND THUNDERSTORMS ARE AIDED BY A UPPER
SPEED MAX AND MUCAPE OF 3500 J/KG AS SAMPLED BY 00Z BRO SOUNDING.

UPDATED THE GRIDS THROUGH 12Z...RAISING POPS ACROSS THE BOARD
WITH 30S IN THE LOWER VALLEY TO 70S OUT WEST WHERE CONVECTION IS
ONGOING. ALSO ADDED PATCHY FOG ALONG THE COAST AND COASTAL WATERS
AS 4-5 STATUTE MILE VISIBILITIES ARE BEING REPORTED IN THE COASTAL
WATERS AND ALSO THROUGH BEACH WEBCAMS. ONLY SLIGHT MASSAGING TO
TEMPERATURE AND WIND GRIDS NEEDED. UPDATE SENT.

&&

.PREV DISCUSSION... /ISSUED 636 PM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 240312
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1012 PM CDT THU APR 23 2015

.DISCUSSION...WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS
THE UPPER VALLEY INTO ZAPATA COUNTY AS WELL AS ISOLATED SHOWERS
POPPING UP ACROSS THE MIDDLE VALLEY AND NORTHERN RANCHLANDS.
ANOTHER COMPLEX IS WELL SOUTH OF THIS AREA IN NEUVO LEON MOVING
NORTHEAST. AREAS OF SHOWERS AND THUNDERSTORMS ARE AIDED BY A UPPER
SPEED MAX AND MUCAPE OF 3500 J/KG AS SAMPLED BY 00Z BRO SOUNDING.

UPDATED THE GRIDS THROUGH 12Z...RAISING POPS ACROSS THE BOARD
WITH 30S IN THE LOWER VALLEY TO 70S OUT WEST WHERE CONVECTION IS
ONGOING. ALSO ADDED PATCHY FOG ALONG THE COAST AND COASTAL WATERS
AS 4-5 STATUTE MILE VISIBILITIES ARE BEING REPORTED IN THE COASTAL
WATERS AND ALSO THROUGH BEACH WEBCAMS. ONLY SLIGHT MASSAGING TO
TEMPERATURE AND WIND GRIDS NEEDED. UPDATE SENT.

&&

.PREV DISCUSSION... /ISSUED 636 PM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 232336
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
636 PM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

&&

.PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 232336
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
636 PM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

&&

.PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 232336
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
636 PM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...CIGS AND THE THREAT FOR TSRA THE MAIN CHALLENGES THIS
TAF PERIOD.

TAKING A PEAK AT THE 00Z BRO SOUNDING SHOWS LESS MOISTURE BELOW
THE SUBSIDENCE INVERSION AND IS PROBABLY WHY NOT MUCH IN THE WAY
OF MVFR STRATOCU CLOUDS AROUND CURRENTLY AS COMPARED TO THIS TIME
YESTERDAY. THEREFORE WILL DELAY ONSET OF MVFR CIGS AT OUR TAF
SITES TILL 02Z. IFR CIGS ARE LIKELY PER SHORT TERM MODELS AND SREF
PROBABILITIES SO WILL BRING IFR CIGS AT 04Z. IFR CIGS TO LAST
THROUGH MID MORNING THEN LIFT AND SCATTER INTO STRATOCU.

LOW PRESSURE SLOWLY DEEPENS TO OUR WEST WHICH WILL HELP STRENGTHEN
LOW LEVEL WINDS TONIGHT AND LEAD TO GUSTY WINDS FOR FRIDAY.
DIRECTIONS WILL BE PREDOMINATELY FROM THE SOUTHEAST WITH GUSTS TO
20 KNOTS.

LOOKING ON THE RADAR...SCATTERED TO NUMEROUS TSRA HAS DEVELOPED
OVER NORTHERN MEXICO NOW WITH MORE EXPECTED OVERNIGHT AS
DIFFLUENCE INCREASES AND WEAK PERTURBATIONS MOVE THROUGH THE
SOUTHWEST MID/UPPER FLOW. SHORT RANGE MODELS ALSO DEVELOP MORE
CONVECTION LATER THIS EVENING WHICH SWEEPS THROUGH DEEP SOUTH
TEXAS. THE SUBSIDENCE INVERSION AND DRY LOW LEVEL AIR WILL REMAIN
SO CONFIDENCE ISNT GREAT OF REACHING AND IMPACTING THE VALLEY
TERMINALS. IF IT DOES...POSSIBLY BEGINS AFT 03Z UP VALLEY AND
PERHAPS IMPACTING MFE THEN 06-10Z SWEEPING FROM UP VALLEY TO THE
COAST IMPACTING ALL TERMINALS. WILL METWATCH AND AMEND TAFS AS
NEEDED.

&&

.PREV DISCUSSION... /ISSUED 252 PM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.

MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




000
FXUS64 KBRO 231952
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
252 PM CDT THU APR 23 2015

.SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.


&&

.MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  75  86  75  85 /  10  20  20  20
BROWNSVILLE          76  88  76  89 /  10  20  20  20
HARLINGEN            76  89  76  91 /  10  20  20  20
MCALLEN              78  91  78  92 /  20  20  30  30
RIO GRANDE CITY      75  94  74  94 /  30  20  40  30
SOUTH PADRE ISLAND   74  82  74  80 /  10  20  20  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/54/65





000
FXUS64 KBRO 231952
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
252 PM CDT THU APR 23 2015

.SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.


&&

.MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  75  86  75  85 /  10  20  20  20
BROWNSVILLE          76  88  76  89 /  10  20  20  20
HARLINGEN            76  89  76  91 /  10  20  20  20
MCALLEN              78  91  78  92 /  20  20  30  30
RIO GRANDE CITY      75  94  74  94 /  30  20  40  30
SOUTH PADRE ISLAND   74  82  74  80 /  10  20  20  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/54/65




000
FXUS64 KBRO 231952
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
252 PM CDT THU APR 23 2015

.SHORT TERM /NOW THROUGH FRIDAY NIGHT/...RADAR IMAGERY BEGINNING TO
SHOW THE FORMING STAGES OF THUNDERSTORMS WELL TO THE SOUTHWEST ON
THE MOUNTAINS IN MEXICO. THIS IS DUE TO THE DAYTIME PEAK HEATING
CONVECTION BEING ENHANCED BY GOOD DIVERGENCE ALOFT AND THE ARRIVAL
OF A SMALL SHORTWAVE. STORM MOTION STILL CURRENTLY AIMING TO THE
NE...WHILE NICE CAPE VALUES BEGINNING TO INCREASE...ESPECIALLY OUT
WEST. STILL CONCERNED ABOUT THE CAPPING INVERSION...WITH H8 TEMPS
STILL 20 TO 22C. THERE WAS SOME CONVECTION LATE LAST NIGHT ACROSS
THE AREA...SO THUNDERSTORM ACTIVITY WILL STILL BE A THREAT EVEN WITH
THE CAP. ANY THUNDERSTORMS THAT DO DEVELOP WILL QUICKLY BECOME
STRONG...POSSIBLY SEVERE. WILL ALSO NEED TO WATCH THE SEABREEZE
MOVING INLAND...AS THIS COULD PROVIDE A SFC BOUNDARY FOR DEVELOPMENT
AND LOCALLY INCREASE SHEAR OF ANY STORMS THAT TRY TO CROSS IT. ANY
STORMS THAT DO DEVELOP WILL HAVE DEEP MOISTURE TO WORK WITH...SO
HEAVY DOWNPOURS WILL BE AN ISSUE.

CONDITIONS WILL RELAX SOME FRIDAY MORNING AS THE MIDLEVEL TROUGH
SWEEPS AWAY FROM TEXAS...WITH LOWERED MIDLEVEL INSTABILITY. DAYTIME
HEATING WILL STILL BRING THE POSSIBILITY OF THUNDERSTORMS ON THE
MOUNTAINS IN MEXICO...BUT WITH A CONTINUED CAPPING INVERSION AND NO
UPPER SUPPORT...THEY WILL HAVE A MUCH HARDER TIME CROSSING THE
RIVER. TEMPERATURES FRIDAY WILL REACH RIGHT AROUND 90 DEGREES.

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...THE CWA IS CURRENTLY IN
SPC`S MARGINAL RISK FOR SEVERE TSTM AREA FOR SATURDAY. CONTINUED
SOUTHWEST FLOW ALOFT WILL PROVIDE A MECHANISM FOR MID LEVEL ENERGY
TO DESTABILIZE THE ATMOSPHERE...WHILE ELEVATED SURFACE DEW POINTS
REPRESENTS THE LOW LEVEL FUEL FOR CONVECTIVE DEVELOPMENT. THE MAIN
THREAT WILL LIKLEY BE CONVECTION MOVING IN FROM THE WEST...HAVING
DEVELOPED OVER THE FRONT RANGE OF THE MEXICAN SIERRAS.

WITH ONE SHORTWAVE TROUGH EXITING OVER THE MIDWEST...AND ANOTHER
DIGGING SOUTH ALONG THE WEST COAST...CONDITIONS WILL IMPROVE
SOMEWHAT AS A WEAK INDUCED RIDGE SETS UP OVER THE NORTHWEST GULF. TO
BE SURE...WITH SOUTHWEST FLOW ALOFT STILL PRESENT...THERE WILL
CONTINUE TO BE A LOW END POTENTIAL FOR SOME CONVECTION FROM THE
WEST...BUT AFTER SATURDAY NO MENTION WILL BE CARRIED IN THE FORECAST
GOING INTO SUNDAY. THAT SAID...THE NEXT TROUGH WILL MOVE OVER THE
FOUR CORNERS SATURDAY NIGHT INTO SUNDAY...THOUGH ITS HIGHER LATITUDE
TRAJECTORY WILLCAUSE MORE TROUBLE FOR NORTH CENTRAL AND EAST TEXAS
SUNDAY NIGHT. STILL...WARM SECTOR CONVECTION COULD BECOME STRONG
OVER THE COASTAL BEND AND RIO GRANDE PLAINS SUNDAY NIGHT INTO
MONDAY...WITH SOME ACTIVITY POSSIBLE FOR THE RANCHLANDS AND BRUSH
COUNTRY. LOCALLY...AN INITIAL WIND SHIFT TO NORTHWEST ALONG WITH
DRIER AIR COULD OCCUR AS EARLY AS LATE MONDAY...WHICH WOULD PROVIDE
SOME CLEARING...AND BOTH THE GFS AND ECMWF ARE SIMILAR WITH THE
GENERAL EVOLUTION OF THE SCENARIO...BUT BOTH ALSO BRING THE TRUE
FRONT IN TUESDAY MORNING AS THE UPPER LOW LIFTS NORTHEAST OUT OF
TEXAS.

THUS...ON TUESDAY...WINDS ALOFT SHOULD BE MORE OUT OF THE NORTHWEST
AND CONDITIONS WILL IMPROVE WITH CLEAR SKIES AND MILDER TEMPS. TEMPS
WILL BE NEAR OR EVEN SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY
AS NEAR CHAMBER OF COMMERCE WEATHER IS EXPECTED.


&&

.MARINE...
NOW THROUGH FRIDAY NIGHT...CONSISTENT CONDITIONS WILL CONTINUE AS
SOUTHEAST WINDS REMAIN AROUND 10KTS. THIS WILL CONTINUE TO PRODUCE
GENERALLY 2 TO 4 FOOT SEAS THROUGH FRIDAY NIGHT.

SATURDAY THROUGH MONDAY...A MODERATE PRESSURE GRADIENT OVER THE WEST
GULF WILL GENERATE LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND
LOW TO MODERATE SEAS WITH A SWELL COMPONENT DUE TO THE PERSISTENT
SOUTHEAST FETCH. ISOLATED SHOWERS AND THUNDERSTORMS MAY CONTINUE
FROM THE SHORT TERM INTO SATURDAY...BUT WILL THEN END. AN UPPER LOW
WILL TRACK ACROSS THE SOUTHWEST U.S. FROM WEST TO EAST OVER THE
WEEKEND SETTING UP THE NEXT SYSTEM TO AFFECT DEEP SOUTH TEXAS AND
THE LOWER TEXAS COAST EARLY IN THE WEEK. THE GFS IS FORECASTING AN
INITIAL SHIFT TO MODERATE NORTH WINDS MONDAY AFTN AS A PREFRONTAL
TROUGH MOVES THROUGH THE AREA...WITH THE MAIN FRONT ARRIVING TUESDAY
MORNING. THE ECMWF IS LESS SUCCESSFUL IN SHIFTING WINDS MONDAY...
KEEPING THEM LIGHT ONSHORE...BUT DOES BRING SHOWER AND THUNDERSTORM
CHANCES BACK INTO THE PICTURE...WITH A FRONT ON TUESDAY AS PER THE
GFS. STRONGER NORTHWEST TO NORTH WINDS BEHIND THE FRONT WILL RESULT
IN SMALL CRAFT ADVISORY CONDITIONS ON TUESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  75  86  75  85 /  10  20  20  20
BROWNSVILLE          76  88  76  89 /  10  20  20  20
HARLINGEN            76  89  76  91 /  10  20  20  20
MCALLEN              78  91  78  92 /  20  20  30  30
RIO GRANDE CITY      75  94  74  94 /  30  20  40  30
SOUTH PADRE ISLAND   74  82  74  80 /  10  20  20  20

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64/54/65





000
FXUS64 KBRO 231736 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1236 PM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOW CLOUDS HAVE BEEN SLOW TO ERODE TODAY...AS VERY
DENSE MOISTURE REMAINS TRAPPED UNDER INVERSION AROUND 4500 FEET.
SOME THINNING WILL HAPPEN THIS AFTERNOON...BUT CLOUD COVER WILL
LIKELY REMAIN OVERCAST JUST ABOVE 3000 THROUGH THE REST OF THE
DAY. LOW CLOUD CONDITIONS RETURN TONIGHT SIMILAR TO LAST NIGHT.
WINDS WILL REMAIN FROM THE SOUTHEAST AROUND 10KTS TODAY...LOWERING
TO AROUND 5KTS OVERNIGHT. SLIGHT DECREASES IN VIS NOTED AREAWIDE
DUE TO SMOKE FROM THE SOUTHEAST...BUT HAVE NO REPORTS OF INBOUND
VIS ISSUES YET.

&&

.PREV DISCUSSION... /ISSUED 649 AM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...BRO RADAR SHOWS A WEAKENING AREA OF SHOWERS MOVING
ACROSS THE RIO GRANDE VALLEY THIS MORNING AND WILL MENTION VCSH
THROUGH 14Z. OTHERWISE...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION HAS RESULTED IN CEILINGS RANGING FROM 400 FEET AT BRO AT
PIL TO AROUND 1500 FEET AT HRL WITH VISIBILITIES BETWEEN 3 TO 5SM
DUE TO FOG. A MIX OF IFR AND MVFR CONDITIONS WILL PREVAIL AT ALL
OF THE RIO GRANDE VALLEY TERMINALS THROUGH MID MORNING. CEILINGS
WILL GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE. IFR CEILINGS POSSIBLE AFTER 04Z AT
BRO/HRL AND 05Z AT MFE.

PREV DISCUSSION... /ISSUED 437 AM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64





000
FXUS64 KBRO 231736 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1236 PM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOW CLOUDS HAVE BEEN SLOW TO ERODE TODAY...AS VERY
DENSE MOISTURE REMAINS TRAPPED UNDER INVERSION AROUND 4500 FEET.
SOME THINNING WILL HAPPEN THIS AFTERNOON...BUT CLOUD COVER WILL
LIKELY REMAIN OVERCAST JUST ABOVE 3000 THROUGH THE REST OF THE
DAY. LOW CLOUD CONDITIONS RETURN TONIGHT SIMILAR TO LAST NIGHT.
WINDS WILL REMAIN FROM THE SOUTHEAST AROUND 10KTS TODAY...LOWERING
TO AROUND 5KTS OVERNIGHT. SLIGHT DECREASES IN VIS NOTED AREAWIDE
DUE TO SMOKE FROM THE SOUTHEAST...BUT HAVE NO REPORTS OF INBOUND
VIS ISSUES YET.

&&

.PREV DISCUSSION... /ISSUED 649 AM CDT THU APR 23 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...BRO RADAR SHOWS A WEAKENING AREA OF SHOWERS MOVING
ACROSS THE RIO GRANDE VALLEY THIS MORNING AND WILL MENTION VCSH
THROUGH 14Z. OTHERWISE...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION HAS RESULTED IN CEILINGS RANGING FROM 400 FEET AT BRO AT
PIL TO AROUND 1500 FEET AT HRL WITH VISIBILITIES BETWEEN 3 TO 5SM
DUE TO FOG. A MIX OF IFR AND MVFR CONDITIONS WILL PREVAIL AT ALL
OF THE RIO GRANDE VALLEY TERMINALS THROUGH MID MORNING. CEILINGS
WILL GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE. IFR CEILINGS POSSIBLE AFTER 04Z AT
BRO/HRL AND 05Z AT MFE.

PREV DISCUSSION... /ISSUED 437 AM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTURBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

64




000
FXUS64 KBRO 231149 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
649 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...BRO RADAR SHOWS A WEAKENING AREA OF SHOWERS MOVING
ACROSS THE RIO GRANDE VALLEY THIS MORNING AND WILL MENTION VCSH
THROUGH 14Z. OTHERWISE...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION HAS RESULTED IN CEILINGS RANGING FROM 400 FEET AT BRO AT
PIL TO AROUND 1500 FEET AT HRL WITH VISIBILITIES BETWEEN 3 TO 5SM
DUE TO FOG. A MIX OF IFR AND MVFR CONDITIONS WILL PREVAIL AT ALL
OF THE RIO GRANDE VALLEY TERMINALS THROUGH MID MORNING. CEILINGS
WILL GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE. IFR CEILINGS POSSIBLE AFTER 04Z AT
BRO/HRL AND 05Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 437 AM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTRUBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





000
FXUS64 KBRO 231149 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
649 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...BRO RADAR SHOWS A WEAKENING AREA OF SHOWERS MOVING
ACROSS THE RIO GRANDE VALLEY THIS MORNING AND WILL MENTION VCSH
THROUGH 14Z. OTHERWISE...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION HAS RESULTED IN CEILINGS RANGING FROM 400 FEET AT BRO AT
PIL TO AROUND 1500 FEET AT HRL WITH VISIBILITIES BETWEEN 3 TO 5SM
DUE TO FOG. A MIX OF IFR AND MVFR CONDITIONS WILL PREVAIL AT ALL
OF THE RIO GRANDE VALLEY TERMINALS THROUGH MID MORNING. CEILINGS
WILL GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE. IFR CEILINGS POSSIBLE AFTER 04Z AT
BRO/HRL AND 05Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 437 AM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTRUBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 231149 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
649 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...BRO RADAR SHOWS A WEAKENING AREA OF SHOWERS MOVING
ACROSS THE RIO GRANDE VALLEY THIS MORNING AND WILL MENTION VCSH
THROUGH 14Z. OTHERWISE...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION HAS RESULTED IN CEILINGS RANGING FROM 400 FEET AT BRO AT
PIL TO AROUND 1500 FEET AT HRL WITH VISIBILITIES BETWEEN 3 TO 5SM
DUE TO FOG. A MIX OF IFR AND MVFR CONDITIONS WILL PREVAIL AT ALL
OF THE RIO GRANDE VALLEY TERMINALS THROUGH MID MORNING. CEILINGS
WILL GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE. IFR CEILINGS POSSIBLE AFTER 04Z AT
BRO/HRL AND 05Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 437 AM CDT THU APR 23 2015/

SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTRUBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.

MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





000
FXUS64 KBRO 230937
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
437 AM CDT THU APR 23 2015

.SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR IMAGERY SHOWS
AN MID LEVEL TROUGH/LOW OFF THE SOUTHERN CALIFORNIA COAST...A WEAK
DISTURBANCE MOVING OVER NORTHEAST MEXICO AND RIDGING OVER TEXAS. AT
THE SURFACE...BROAD HIGH PRESSURE CONTINUES ACROSS THE EASTERN GULF
OF MEXICO THIS MORNING. WIDESPREAD FOG REDUCING VISIBILITIES TO
BETWEEN 3 AND 5 MILES WILL LINGER ACROSS THE AREA THROUGH MID
MORNING BEFORE DISSIPATING. CURRENT BRO RADAR SHOWS ISOLATED
CONVECTION ACROSS THE MEXICAN STATES OF NUEVO LEON AND TAMAULIPAS
EXTENDING INTO PORTIONS OF THE RIO GRANDE VALLEY. THIS ACTIVITY IS
BEING GENERATED BY AN UPPER LEVEL DISTRUBANCE PASSING OVERHEAD.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS DEEP
SOUTH TEXAS NOW THROUGH AROUND NOON WITH ADDITIONAL CONVECTION
DEVELOPING LATER THIS AFTERNOON.

THE 500MB TROUGH/LOW DEEPENS OVER SOUTHERN CALIFORNIA/BAJA REGION AS
THE MID LEVEL RIDGE BUILDS OVER TEXAS TODAY. THE MID LEVEL TROUGH
EJECTS NORTHEAST AS THE 500MB RIDGE MOVES EAST TONIGHT INTO FRIDAY.
LOW LEVEL MOISTURE WILL CONTINUE TO ADVECT ACROSS THE REGION
COURTESY OF SOUTHEAST SURFACE FLOW. THE SOUTHWEST FLOW ALOFT WILL
CONTINUE TO PROVIDE CAPPING AND SUBSIDENCE...ESPECIALLY ACROSS THE
EASTERN PORTIONS OF THE AREA.

EXCEPT FOR THE COASTAL COUNTIES...DEEP SOUTH TEXAS REMAINS UNDER A
MARGINAL RISK OF SEVERE WEATHER FOR TODAY AND TONIGHT. ISOLATED
SHOWERS AND THUNDERSTORMS AND FOG WILL BE POSSIBLE THIS MORNING.
OTHERWISE... TEMPERATURES TODAY WILL BE VERY WARM WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOWER 90S ACROSS THE UPPER VALLEY AND WEST UNDER
ABUNDANT HIGH CLOUDS OVERHEAD. SHORT WAVE ENERGY WILL ARRIVE OVER
THE MEXICAN MOUNTAINS LATE THIS AFTERNOON INTO THIS EVENING. THIS
WILL RESULT IN CONVECTION DEVELOPING ACROSS SIERRA MADRE AND MOVING
INTO THE WESTERN PORTIONS OF DEEP SOUTH TEXAS THIS EVENING INTO
TONIGHT. WILL HOLD OFF ON MENTIONING SEVERE WORDING AT THIS TIME DUE
TO LOW PROBABILITY CHANCES...HOWEVER AN ISOLATED SEVERE CELL CAN NOT
BE RULED OUT. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO UPPER
70S. FRIDAY WILL BE VERY WARM WITH HIGH TEMPERATURES IN THE 90S...
EXCEPT FOR THE 80S NEAR THE COAST. THE STORM PREDICTION CENTER HAS
ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE
THUNDERSTORMS FRIDAY. AGAIN...CAPPING AND SUBSIDENCE ACROSS THE AREA
SHOULD SUPPORT ONLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS.

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...MAIN CONCERN IN THE
FIRST 24 HOURS OF THE LONG TERM PORTION OF THE FORECAST WILL BE
THUNDERSTORMS. MODELS INDICATE CONVECTION WILL FIRE OVER THE HIGH
TERRAIN OF NEIGHBORING MEXICO FRIDAY NIGHT DUE TO A WEAK 500 MB
TROUGH RIDING WITHIN THE SOUTHWEST-TO-NORTHEAST MID-LEVEL FLOW...
WITH THE CONVECTION POSSIBLY ENHANCED BY A WEAK SURFACE BOUNDARY
OVER THE WESTERN PORTION OF THE BRO CWFA. STORM PREDICTION CENTER
HAS ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY IN A
MARGINAL RISK OF SEVERE WEATHER FOR FRIDAY NIGHT...WITH A SLIGHT
RISK OF SEVERE WEATHER FOR THE ENTIRE CRP CWFA AND WFO/S FARTHER
NORTH...WITH AN ENHANCED RISK OVER EAST AND NORTHEAST TEXAS. AFTER
COORDINATING WITH NEIGHBORING WFO CRP...WILL HOLD OFF ON
MENTIONING SEVERE THUNDERSTORMS WITHIN THE BRO CWFA FOR THE FRIDAY
NIGHT TIME FRAME...BUT WILL RE-EXAMINE THE POSSIBLE FUTURE NEED OF
THE MENTION WITH SUCCESSIVE SHIFTS. FOR NOW...ISOLATED/SCATTERED
SHOWERS/THUNDERSTORMS WILL RESULT FRIDAY NIGHT AND SATURDAY...
WITH THE REMAINDER OF THE FORECAST DRY DUE TO DRIER AIR PUSHING
INTO THE REGION ON SURFACE BOUNDARIES...THE MOST SIGNIFICANT OF
WHICH IS THE PASSAGE OF A COLD FRONT ON TUESDAY. EXPECT WELL ABOVE
NORMAL TEMPERATURES IN ADVANCE OF THE FRONT AND MORE NORMAL IN THE
WAKE OF THE FRONTAL PASSAGE.
&&

.MARINE...NOW THROUGH FRIDAY...BUOY 42020 CURRENTLY REPORTS
SOUTH WINDS AROUND 10 KNOTS WITH SEAS AROUND 3.3 FEET. BROAD SURFACE
HIGH PRESSURE ACROSS THE EASTERN GULF OF MEXICO WILL MAINTAIN LIGHT
TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY THROUGH FRIDAY.

FRIDAY NIGHT THROUGH WEDNESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST WITH SURFACE HIGH PRESSURE
DOMINANT OVER THE WESTERN GULF OF MEXICO THROUGH A MAJORITY OF
THE FORECAST PERIOD. SMALL CRAFT ADVISORIES WILL QUITE POSSIBLY
BE NEEDED ON TUESDAY AND WEDNESDAY DUE TO STRONGER WINDS AND
HIGHER SEAS PRODUCED BY THE TUESDAY MORNING PASSAGE OF A COLD
FRONT.
&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  84  76  90  76 /  10  10  20  20
BROWNSVILLE          87  76  90  76 /  10  10  20  20
HARLINGEN            90  76  94  75 /  20  10  20  20
MCALLEN              91  75  92  76 /  20  20  20  30
RIO GRANDE CITY      93  75  96  76 /  20  30  20  40
SOUTH PADRE ISLAND   79  75  86  76 /  10  10  20  20
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
MESO/WX4PPT...BILLINGS-58




000
FXUS64 KBRO 230602 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
102 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN INVERSION HAS
RESULTED IN IFR CONDITIONS ACROSS ALL OF THE RIO GRANDE VALLEY
TERMINALS EARLY THIS MORNING. VISIBILITIES HAVE ALSO DROPPED INTO
THE 5 TO 6SM RANGE THIS MORNING DUE TO LIGHT FOG. CEILINGS WILL
GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 644 PM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 230602 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
102 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN INVERSION HAS
RESULTED IN IFR CONDITIONS ACROSS ALL OF THE RIO GRANDE VALLEY
TERMINALS EARLY THIS MORNING. VISIBILITIES HAVE ALSO DROPPED INTO
THE 5 TO 6SM RANGE THIS MORNING DUE TO LIGHT FOG. CEILINGS WILL
GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 644 PM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





000
FXUS64 KBRO 230602 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
102 AM CDT THU APR 23 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN INVERSION HAS
RESULTED IN IFR CONDITIONS ACROSS ALL OF THE RIO GRANDE VALLEY
TERMINALS EARLY THIS MORNING. VISIBILITIES HAVE ALSO DROPPED INTO
THE 5 TO 6SM RANGE THIS MORNING DUE TO LIGHT FOG. CEILINGS WILL
GRADUALLY INCREASE TO MVFR LEVELS BY MID MORNING WITH VFR
CONDITIONS AROUND NOON. MVFR CEILINGS WILL RETURN AFTER 01Z AT
BRO/HRL AND AFTER 03Z AT MFE.

&&

.PREV DISCUSSION... /ISSUED 644 PM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 222344
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
644 PM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 222344
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
644 PM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




000
FXUS64 KBRO 222344
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
644 PM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55





000
FXUS64 KBRO 222344
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
644 PM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...MOISTURE CONTINUES TO ADVECT FROM THE SOUTHEAST
UNDERNEATH INVERSION LOCATED AROUND 1500 FEET. TABULAR DATA AS
WELL AS SHORT RANGE MODELS SHOW MVFR DEVELOPING EARLY THIS EVENING
WITH IFR CONDITIONS OVERSPREADING THE TERMINALS AFTER 06Z. WITH
HIGH PRESSURE NEARBY WINDS WILL GENERALLY BE FROM THE SOUTHEAST
AND SPEEDS BELOW 12 KNOTS. CIGS WILL LIFT BACK TO MVFR BY MID
MORNING WITH VFR CONDITIONS AROUND NOON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 308 PM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




000
FXUS64 KBRO 222008
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
308 PM CDT WED APR 22 2015

.SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

.LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

&&

.MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64





000
FXUS64 KBRO 222008
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
308 PM CDT WED APR 22 2015

.SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

.LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

&&

.MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64





000
FXUS64 KBRO 222008
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
308 PM CDT WED APR 22 2015

.SHORT TERM /NOW THROUGH THURSDAY NIGHT/...MID LEVEL RIDGE WILL
BUILD OVER TEXAS NEXT 24 HOURS AS MID LEVEL TROUGH/LOW DEEPENS
OVER SOUTHERN CALIFORNIA AND THEN BEGINS TO EJECT. RIDGE WILL THEN
SHIFT EAST BUT IN THE MEAN TIME THE UPPER PATTERN OVER THE
SOUTHWEST U.S. WILL AMPLIFY. SOUTHEAST SFC INFLOW SUPPORTED BY
BROAD HIGH PRESSURE OVER THE GULF AND SOUTHEAST U.S. WILL MAINTAIN
A RICH LOW LEVEL MOISTURE FEED WHILE SOUTHWEST FLOW ALOFT WILL
INITIALLY PROVIDE A STABILIZING CAP AND SUBSIDENCE. OVER TIME
HOWEVER...SUBSIDENCE WILL HELP DAY TIME SURFACE TEMPERATURES
WARM...AND ENERGY MOVING AROUND THE BASE OF THE EJECTING TROUGH
WILL TAP INTO THE LOWER LVL ENERGY TO HELP TRIGGER CONVECTION TO
THE WEST AND NORTH.

FOR THIS EVENING AND TONIGHT...ONGOING CONVECTION TO THE NORTH OF
THE CWA WILL WANE AND SHOULD NOT PLAY A MAJOR ROLE FOR THE CWA. LOW
TEMPS WILL BE IN THE 70S WITH OVC SKIES AND LIGHT SOUTHEAST WINDS.

ON THURSDAY...A MARGINAL RISK AREA WILL CONTINUE OVER THE AREA. HIGH
TEMPS WILL PUSH INTO THE LOWER 90S WEST OF THE COASTAL AREAS...EVEN
WITH THIN CIRRUS MOVING OVER FROM THE SOUTHWEST. SHORT WAVE ENERGY
WILL ARRIVE OVER THE MEXICAN MOUNTAINS THURSDAY EVE...AND TSTMS WILL
IGNITE AND MOVE EAST...MOVING OVER THE UPPER AND MID VALLEYS LATE
THURSDAY AND THURSDAY NIGHT. DISCUSSED PREVIOUSLY A MILDER RENDITION
FOR THE THU NIGHT WEATHER...OPTING NOT TO CARRY SEVERE WORDING AT
THIS TIME DUE TO LOW PROBABILITY CHANCES...WITH THE UNDERSTANDING
THAT AN ISOLTD SEVERE CELL CAN NOT BE RULED OUT.

.LONG TERM /FRIDAY THROUGH TUESDAY/...BY FRIDAY MORNING, THE
MIDLEVEL TROUGH WILL BE SWEEPING NEWD THROUGH THE TEXAS PANHANDLE
INTO KANSAS. THIS WILL KEEP THE BEST DYNAMICS WELL TO THE NORTH.
AT THE SFC, LOWER ATMOSPHERE WILL BE PRIMED WITH AMPLE MOISTURE
WITH HIGHER CAPES. THE BIG ISSUE IS THE CAPPING. FORECAST STILL
SHOWS H8 TEMPERATURES 20 TO 25 DEGREES ALL DAY FRIDAY, PEAKING IN
THE EVENING. BEST THREAT FOR ANY THUNDERSTORM ACTIVITY WOULD BE
FOR THE FAR WESTERN VALLEY AGAIN, WITH MOUNTAIN THUNDERSTORMS
MOVING ENE ACROSS THE RIVER AFTER SUNSET. WITH THE LACK OF SUPPORT
ALOFT AND THE CAP, CAN`T GO MORE THAN A 20 TO 30 POP. IF ANY
STORMS TO REACH THE CWA, THERE IS THE RISK FOR THEM BEING STRONG
TO SEVERE. WITH H8 TEMPS AT 20 TO 25 C, THAT TRANSLATES TO HIGH
TEMPERATURES IN THE 90S FOR MOST OF THE REGION. WITH DEWPOINTS IN
THE 70S, HEAT INDEX VALUES WILL PUSH 100 TO 105 DURING THE
AFTERNOON.

SATURDAY WILL BE A QUIETER DAY AS WEAK RIDGING BRIEFLY REIGNS
ALOFT. THE ONLY POSSIBILITY FOR A THUNDERSTORM WOULD BE IF THE
DRYLINE WERE ABLE TO REACH THE WESTERN VALLEY LATER SATURDAY.
GOING TO BE TOUGH TO DO. TEMPERATURES AGAIN REACH THE 90S FOR THE
VALLEY WITH HUMID CONDITIONS CONTINUING.

LONGER TERM PERIOD BRINGS THE NEXT TROUGH DIVING DOWN THE ROCKIES
INTO TEXAS...WITH ANOTHER ROUND OF IMPROVED DYNAMIC SUPPORT ALOFT.
MODELS ARE STILL TRYING TO BRING A FRONT ACROSS TEXAS SOMETIME
EARLY NEXT WEEK...WHICH WOULD BE A USEFUL TRIGGERING MECHANISM
FOR SHOWER FORMATION. UNTIL MODELS COME TOGETHER BETTER ON A
PASSAGE TIMING AND STRENGTH, CAN ONLY CAST A WIDE NET FOR NOW.

&&

.MARINE...
NOW THROUGH THURSDAY NIGHT...MID LEVEL RIDGING WILL BUILD OVER THE
GULF OF MEXICO...SUPPORTING BROAD SURFACE HIGH PRESSURE. THIS WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS.
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE.

FRIDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE ACROSS THE
GULF WATERS, WITH MODEST SOUTHEAST FLOW 10 TO 15 KNOTS CREATING
SEAS GENERALLY 3 TO 4 FEET.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64




000
FXUS64 KBRO 221656 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1156 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION AND REGULAR FORECASTS.
THOUGH IN A MARGINAL RISK AREA FOR THURSDAY AND THURSDAY NIGHT...
THE CHANCE OF ANY SEVERE STORMS IS CURRENTLY LOW AND ANY SEVERE
STORMS THAT DO FORM THURSDAY TO THURSDAY NIGHT WILL BE ISOLATED
AND LIMITED IN DURATION AND/OR COVERAGE AND/OR INTENSITY. DESPITE
THE PRESENCE OF LOW LEVEL INSTABILITY...RIDGING ALOFT WILL PROVIDE
SUBSIDENCE AND WILL HELP INHIBIT DEEP DEVELOPMENT. REMOVED SEVERE
WORDING FROM THE REGULAR FORECAST IN FAVOR OF HWO AND AFD MENTION.

&&

.AVIATION...AMPLE LOW LEVEL MOISTURE AND A STABLE SOUNDING HAVE
KEPT MVFR OR LOWER CEILINGS GOING AT THE TAF SITES. THE TREND WILL
CONTINUE THROUGH TONIGHT WITH LIGHT SOUTHEAST WINDS. LIGHT FOG OR
HAZE WILL REDUCE VISIBILITY SLIGHTLY. CEILINGS MAY BE A LITTLE
HIGHER OVER MFE...AND MAY LIFT TO VFR ON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 656 AM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF MVFR AND LOW END VFR CONDITIONS ACROSS DEEP SOUTH TEXAS
THIS MORNING. CONDITIONS WILL GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP TODAY WITH
DAY TIME HEATING AND A WEAK UPPER LEVEL DISTURBANCE MOVING
OVERHEAD THIS AFTERNOON. MVFR CONDITIONS DEVELOP AGAIN TONIGHT
MAINLY AFTER 03Z.

PREV DISCUSSION... /ISSUED 431 AM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.

MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64/58





000
FXUS64 KBRO 221656 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1156 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION AND REGULAR FORECASTS.
THOUGH IN A MARGINAL RISK AREA FOR THURSDAY AND THURSDAY NIGHT...
THE CHANCE OF ANY SEVERE STORMS IS CURRENTLY LOW AND ANY SEVERE
STORMS THAT DO FORM THURSDAY TO THURSDAY NIGHT WILL BE ISOLATED
AND LIMITED IN DURATION AND/OR COVERAGE AND/OR INTENSITY. DESPITE
THE PRESENCE OF LOW LEVEL INSTABILITY...RIDGING ALOFT WILL PROVIDE
SUBSIDENCE AND WILL HELP INHIBIT DEEP DEVELOPMENT. REMOVED SEVERE
WORDING FROM THE REGULAR FORECAST IN FAVOR OF HWO AND AFD MENTION.

&&

.AVIATION...AMPLE LOW LEVEL MOISTURE AND A STABLE SOUNDING HAVE
KEPT MVFR OR LOWER CEILINGS GOING AT THE TAF SITES. THE TREND WILL
CONTINUE THROUGH TONIGHT WITH LIGHT SOUTHEAST WINDS. LIGHT FOG OR
HAZE WILL REDUCE VISIBILITY SLIGHTLY. CEILINGS MAY BE A LITTLE
HIGHER OVER MFE...AND MAY LIFT TO VFR ON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 656 AM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF MVFR AND LOW END VFR CONDITIONS ACROSS DEEP SOUTH TEXAS
THIS MORNING. CONDITIONS WILL GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP TODAY WITH
DAY TIME HEATING AND A WEAK UPPER LEVEL DISTURBANCE MOVING
OVERHEAD THIS AFTERNOON. MVFR CONDITIONS DEVELOP AGAIN TONIGHT
MAINLY AFTER 03Z.

PREV DISCUSSION... /ISSUED 431 AM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.

MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64/58




000
FXUS64 KBRO 221656 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1156 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION AND REGULAR FORECASTS.
THOUGH IN A MARGINAL RISK AREA FOR THURSDAY AND THURSDAY NIGHT...
THE CHANCE OF ANY SEVERE STORMS IS CURRENTLY LOW AND ANY SEVERE
STORMS THAT DO FORM THURSDAY TO THURSDAY NIGHT WILL BE ISOLATED
AND LIMITED IN DURATION AND/OR COVERAGE AND/OR INTENSITY. DESPITE
THE PRESENCE OF LOW LEVEL INSTABILITY...RIDGING ALOFT WILL PROVIDE
SUBSIDENCE AND WILL HELP INHIBIT DEEP DEVELOPMENT. REMOVED SEVERE
WORDING FROM THE REGULAR FORECAST IN FAVOR OF HWO AND AFD MENTION.

&&

.AVIATION...AMPLE LOW LEVEL MOISTURE AND A STABLE SOUNDING HAVE
KEPT MVFR OR LOWER CEILINGS GOING AT THE TAF SITES. THE TREND WILL
CONTINUE THROUGH TONIGHT WITH LIGHT SOUTHEAST WINDS. LIGHT FOG OR
HAZE WILL REDUCE VISIBILITY SLIGHTLY. CEILINGS MAY BE A LITTLE
HIGHER OVER MFE...AND MAY LIFT TO VFR ON THURSDAY.

&&

.PREV DISCUSSION... /ISSUED 656 AM CDT WED APR 22 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF MVFR AND LOW END VFR CONDITIONS ACROSS DEEP SOUTH TEXAS
THIS MORNING. CONDITIONS WILL GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP TODAY WITH
DAY TIME HEATING AND A WEAK UPPER LEVEL DISTURBANCE MOVING
OVERHEAD THIS AFTERNOON. MVFR CONDITIONS DEVELOP AGAIN TONIGHT
MAINLY AFTER 03Z.

PREV DISCUSSION... /ISSUED 431 AM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.

MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/64/58





000
FXUS64 KBRO 221156 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
656 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF MVFR AND LOW END VFR CONDITIONS ACROSS DEEP SOUTH TEXAS
THIS MORNING. CONDITIONS WILL GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP TODAY WITH
DAY TIME HEATING AND A WEAK UPPER LEVEL DISTURBANCE MOVING
OVERHEAD THIS AFTERNOON. MVFR CONDITIONS DEVELOP AGAIN TONIGHT
MAINLY AFTER 03Z.

&&

.PREV DISCUSSION... /ISSUED 431 AM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.

MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





000
FXUS64 KBRO 221156 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
656 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF MVFR AND LOW END VFR CONDITIONS ACROSS DEEP SOUTH TEXAS
THIS MORNING. CONDITIONS WILL GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP TODAY WITH
DAY TIME HEATING AND A WEAK UPPER LEVEL DISTURBANCE MOVING
OVERHEAD THIS AFTERNOON. MVFR CONDITIONS DEVELOP AGAIN TONIGHT
MAINLY AFTER 03Z.

&&

.PREV DISCUSSION... /ISSUED 431 AM CDT WED APR 22 2015/

SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.

MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 220931
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
431 AM CDT WED APR 22 2015

.SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.
&&

.MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.
&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  81  76  85  74 /  20  10  20  20
BROWNSVILLE          84  76  87  74 /  20  10  20  20
HARLINGEN            85  75  90  74 /  20  10  20  20
MCALLEN              87  76  91  74 /  20  10  20  30
RIO GRANDE CITY      88  74  93  74 /  20  10  20  40
SOUTH PADRE ISLAND   78  75  82  74 /  20  10  10  20
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
MESO/WX4PPT...BILLINGS-58




000
FXUS64 KBRO 220931
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
431 AM CDT WED APR 22 2015

.SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR IMAGERY
SHOWS AN UPPER LOW OVER SOUTHERN CALIFORNIA AND A WEAK SHORT WAVE
OVER NORTHEAST MEXICO. AT THE SURFACE...HIGH PRESSURE REMAINS
CENTERED OVER THE NORTHEAST GULF OF MEXICO THIS MORNING.

WEAK ONSHORE FLOW SUPPORTED BY SURFACE HIGH PRESSURE TO THE EAST
WILL KEEP LOW LEVEL MOISTURE ELEVATED TODAY. THE 0Z BRO SOUNDING
INDICATES A PRECIPITABLE WATER VALUE OF 1.76 INCHES. THE COMBINATION
OF DAYTIME HEATING AND A WEAK SHORT WAVE MOVING OVER THE REGION
TODAY SHOULD SUPPORT A SLIGHT TO LOW END CHANCE OF SHOWER AND
THUNDERSTORMS TODAY. DRIER AIR WORKS DOWN INTO THE LOWER LAYERS
LATER TODAY AND ALLOWS SOME MILD CAPPING TO DEVELOP. HOWEVER...THE
STORM PREDICTION CENTER HAS ALL OF DEEP SOUTH TEXAS UNDER A MARGINAL
RISK OF SEVERE THUNDERSTORMS TODAY THROUGH THURSDAY. HIGH
TEMPERATURES TODAY WILL RANGE FROM THE LOWER 80S NEAR THE COAST TO
THE MID AND UPPER 80S ELSEWHERE. LOW TEMPERATURES TONIGHT WILL BE IN
THE LOW TO MID 70S. THURSDAY WILL BE VERY WARM TO HOT WITH HIGH
TEMPERATURES IN THE MID TO UPPER 80S ALONG AND EAST OF I-69E/HIGHWAY
77 CORRIDOR WITH LOW TO MID 90S ACROSS THE UPPER VALLEY AND WEST.
DRY CONDITIONS EXPECTED TONIGHT WITH A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY. SOME CONVECTION WILL LIKELY FIRE ALONG THE
SIERRA MADRE MOUNTAINS IN MEXICO THURSDAY AFTERNOON. A FEW STRONG TO
POSSIBLY SEVERE THUNDERSTORMS MAY APPROACH ZAPATA COUNTY BY LATE
THURSDAY AFTERNOON.

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE MAIN CONCERN IN
THE LONG TERM PORTION OF THE FORECAST WILL BE THE POTENTIAL FOR
SEVERE WEATHER DURING THE FIRST 48 HOURS OF THE PERIOD. THE STORM
PREDICTION CENTER PLACES THE ENTIRE BRO CWFA IN A MARGINAL RISK OF
SEVERE WEATHER THURSDAY NIGHT THROUGH SATURDAY MORNING...WITH THE
ENTIRE CRP CWFA AND MOST OF TEXAS IN A SLIGHT RISK OF SEVERE
WEATHER FOR THIS TIME PERIOD. GFS SUGGESTS CONVECTION INITIATING
OVER THE NEIGHBORING MEXICAN STATES OF COAHUILA AND NUEVO LEON DUE
TO SHORTWAVES WITHIN THE SOUTHWEST-TO-NORTHEAST 500 MB FLOW ON
THURSDAY NIGHT AND FRIDAY NIGHT...WITH THAT CONVECTION THEN
ADVECTING OVER THE RIO GRANDE VALLEY AND DEEP SOUTH TEXAS. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY SEVERE
THUNDERSTORMS THAT INITIATE...WITH THE MOST LIKELY CHANCE OF
PRECIPITATION BASICALLY ALONG AND WEST OF THE HIGHWAY 281/
INTERSTATE 69C CORRIDOR...WITH A MUCH LESS OPPORTUNITY FOR RAIN
EAST OF THAT LINE. AFTER THE THREAT OF SEVERE WEATHER...THE REST
OF FORECAST APPEARS MAINLY DRY AND QUIET...EXCEPT FOR THE PASSAGE
OF A COLD FRONT ON TUESDAY...AND HOT...WITH TEMPERATURES WELL
ABOVE NORMAL FOR DAYTIME HIGHS AND OVERNIGHT LOWS.
&&

.MARINE...NOW THROUGH THURSDAY...BUOY 42020 CURRENTLY REPORTS
SOUTHEAST WINDS AROUND 12 KNOTS WITH SEAS AROUND 3 FEET. HIGH
PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL MAINTAIN LIGHT TO
MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE TODAY AND THURSDAY.

THURSDAY NIGHT THROUGH TUESDAY...MODERATE WINDS AND SEAS WILL
PREVAIL ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE
FORECAST WITH SURFACE HIGH PRESSURE IN CONTROL OVER THE WESTERN
GULF OF MEXICO. SMALL CRAFT ADVISORIES MAY BE NEEDED ON TUESDAY
DUE TO STRONGER WINDS AND HIGHER SEAS PRODUCED BY THE PASSAGE OF
A COLD FRONT ON THAT DAY.
&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  81  76  85  74 /  20  10  20  20
BROWNSVILLE          84  76  87  74 /  20  10  20  20
HARLINGEN            85  75  90  74 /  20  10  20  20
MCALLEN              87  76  91  74 /  20  10  20  30
RIO GRANDE CITY      88  74  93  74 /  20  10  20  40
SOUTH PADRE ISLAND   78  75  82  74 /  20  10  10  20
&&

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
MESO/WX4PPT...BILLINGS-58





000
FXUS64 KBRO 220603 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
103 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE LOW
AND MID LEVEL CLOUDS ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING.
CEILINGS RANGE FROM AROUND 1700 FEET AT MFE/APY AND T65 TO AROUND
3500 FEET AT BRO/HRL AND PIL. EXPECT MVFR CONDITIONS TO DEVELOP AT
ALL TAF SITES BY 09Z WITH IFR CONDITIONS POSSIBLE BEFORE SUNRISE
AT MFE AS LOW TO MID LEVEL MOISTURE INCREASES AND AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. MVFR CONDITIONS GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP ALONG THE
WEAK BOUNDARY AS IT MOVES NORTHWARD THIS AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 624 PM CDT TUE APR 21 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MID
LEVEL CLOUDS ACROSS THE CWA EARLY THIS EVENING. CEILINGS WERE NEAR
2600FT AT KMFE TO NEAR 3600FT AT KBKS. EXPECT MVFR CONDITIONS TO
DEVELOP THIS EVENING AND IFR CONDITIONS TO DEVELOP WED MORNING AS
LOW TO MID LEVEL MOISTURE INCREASES ACROSS THE RIO GRANDE VALLEY
AND THE NORTHERN RANCHLANDS TONIGHT INTO WEDNESDAY AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. ISOLATED SHOWERS WILL DEVELOP ALONG THIS BOUNDARY
AS IT MOVES NORTHWARD WED AFTERNOON.

PREV DISCUSSION... /ISSUED 249 PM CDT TUE APR 21 2015/
SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...HIGH PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY WITH WEAK H5 RIDGING JUST UPSTREAM AND AN
H5 LOW OVER SOUTHERN CALIFORNIA MOVING UNDER THE WEST COAST RIDGE.
A DEW POINT BOUNDARY HAS PUSHED NORTH OVER DEEP SOUTH TEXAS AND
HAS PROVIDED A FOCUS FOR WEAK ONGOING CONVECTION OVER THE AREA
TODAY.

WEAK ONSHORE FLOW SUPPORTED BY HIGH PRESSURE TO THE EAST WILL KEEP
LOW LEVEL MOISTURE ELEVATED. PWAT VALUES WILL STAY ABOVE 1.5 INCHES
THROUGH THE SHORT TERM. RAIN CHANCES WILL DIMINISH TONIGHT AS THE
INFLUENCE OF A RIGHT REAR ENTRANCE REGION OF THE SUBTROPICAL JET
REPOSITIONS AWAY FROM THE AREA. SATURATED LOWER LAYERS WILL SHRINK
IN DEPTH WHILE MILD CAPPING DEVELOPS. NONETHELESS...THE AREA WILL BE
UNDER A MARGINAL RISK OF SVR THUNDERSTORMS WEDNESDAY AS TEMPERATURES
WARM INTO THE MID AND UPPER 80S AND A WEAK SHORT WAVE MOVES THROUGH
THE FLOW ALOFT. OVERNIGHT LOW TEMPERATURES WILL BE WELL INTO THE 70S
TO MATCH THE ELEVATED DEW POINTS.

LONG TERM /THURSDAY THROUGH MONDAY/...H5 TROUGH CONTINUES TO
DIVE ACROSS THE FOUR CORNERS REGION...WITH FLOW BUCKLING AHEAD OF
IT ACROSS THE SOUTHERN PLAINS. WITH WEAK DIFFLUENCE ALOFT AND
SHORTWAVES ROTATING AROUND THE SOUTHERN END OF THE
TROUGH...THUNDERSTORMS WILL LIKELY FIRE ALONG THE MOUNTAINS IN
MEXICO AND SWEEP ENE ACROSS THE RIO GRANDE PLAINS. THESE
THUNDERSTORMS WILL LIKELY BE STRONG...BUT STEERING FLOW WOULD
LIKELY CONFINE THESE STORMS TO ZAPATA COUNTY AND POINTS NORTH.
CHANCE POPS ALREADY IN FORECAST...WITH NO TWEAKING REQUIRED. SAME
SETUP PROGGED FOR FRIDAY...EXCEPT THE H5 TROUGH TO THE WEST IS
BEGINNING TO FILL IN...DECREASING THE DIFFLUENCE ALOFT.
THUNDERSTORMS WILL LIKELY STILL BE ABLE TO FIRE IN MEXICO...BUT
WILL HAVE MUCH HARDER TIME PROGRESSING ENE ACROSS THE RIO GRANDE.
MODELS ARE NOT AGREEING ON THE PROGRESSION OF THE NEXT TROUGH
DROPPING DOWN THE ROCKIES THIS WEEKEND. BOTH MODELS SHOW A COLD
FRONT MOVING INTO TEXAS THIS WEEKEND. THE MORE PROGRESSIVE PATTERN
WOULD STALL THE FRONT WELL TO THE NORTH...WHILE A TRAILING SLOWER
TROUGH WILL ALLOW THE FRONT INTO SOUTH TEXAS LATE IN THE WEEKEND
OR EARLY NEXT WEEK. WILL HOLD ONTO SLIGHT CHANCE POP FOR NOW FOR
THE CONSIDERABLE UNCERTAINTY IN THE FORECAST.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...HIGHER PRESSURE WILL PREVAIL TO THE
EAST...OVER THE WEST GULF...RESULTING IN LIGHT TO MODERATE SOUTHEAST
QUADRANT WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS OR TSTMS WILL
BE POSSIBLE AT TIMES.

THURSDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE FOR LATE
WEEK INTO THE WEEKEND AS SOUTHEASTERLY FLOW CONTINUES ACROSS THE
WESTERN GULF. SEAS WILL GENERALLY REMAIN IN THE 3 TO 4 FOOT
RANGE. SOME THUNDERSTORMS ACTIVITY IS POSSIBLE LATE THURSDAY
NIGHT WHICH MAY AGITATE SEAS SOMEWHAT...BUT WILL BE BRIEF IN
NATURE.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 220603 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
103 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE LOW
AND MID LEVEL CLOUDS ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING.
CEILINGS RANGE FROM AROUND 1700 FEET AT MFE/APY AND T65 TO AROUND
3500 FEET AT BRO/HRL AND PIL. EXPECT MVFR CONDITIONS TO DEVELOP AT
ALL TAF SITES BY 09Z WITH IFR CONDITIONS POSSIBLE BEFORE SUNRISE
AT MFE AS LOW TO MID LEVEL MOISTURE INCREASES AND AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. MVFR CONDITIONS GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP ALONG THE
WEAK BOUNDARY AS IT MOVES NORTHWARD THIS AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 624 PM CDT TUE APR 21 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MID
LEVEL CLOUDS ACROSS THE CWA EARLY THIS EVENING. CEILINGS WERE NEAR
2600FT AT KMFE TO NEAR 3600FT AT KBKS. EXPECT MVFR CONDITIONS TO
DEVELOP THIS EVENING AND IFR CONDITIONS TO DEVELOP WED MORNING AS
LOW TO MID LEVEL MOISTURE INCREASES ACROSS THE RIO GRANDE VALLEY
AND THE NORTHERN RANCHLANDS TONIGHT INTO WEDNESDAY AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. ISOLATED SHOWERS WILL DEVELOP ALONG THIS BOUNDARY
AS IT MOVES NORTHWARD WED AFTERNOON.

PREV DISCUSSION... /ISSUED 249 PM CDT TUE APR 21 2015/
SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...HIGH PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY WITH WEAK H5 RIDGING JUST UPSTREAM AND AN
H5 LOW OVER SOUTHERN CALIFORNIA MOVING UNDER THE WEST COAST RIDGE.
A DEW POINT BOUNDARY HAS PUSHED NORTH OVER DEEP SOUTH TEXAS AND
HAS PROVIDED A FOCUS FOR WEAK ONGOING CONVECTION OVER THE AREA
TODAY.

WEAK ONSHORE FLOW SUPPORTED BY HIGH PRESSURE TO THE EAST WILL KEEP
LOW LEVEL MOISTURE ELEVATED. PWAT VALUES WILL STAY ABOVE 1.5 INCHES
THROUGH THE SHORT TERM. RAIN CHANCES WILL DIMINISH TONIGHT AS THE
INFLUENCE OF A RIGHT REAR ENTRANCE REGION OF THE SUBTROPICAL JET
REPOSITIONS AWAY FROM THE AREA. SATURATED LOWER LAYERS WILL SHRINK
IN DEPTH WHILE MILD CAPPING DEVELOPS. NONETHELESS...THE AREA WILL BE
UNDER A MARGINAL RISK OF SVR THUNDERSTORMS WEDNESDAY AS TEMPERATURES
WARM INTO THE MID AND UPPER 80S AND A WEAK SHORT WAVE MOVES THROUGH
THE FLOW ALOFT. OVERNIGHT LOW TEMPERATURES WILL BE WELL INTO THE 70S
TO MATCH THE ELEVATED DEW POINTS.

LONG TERM /THURSDAY THROUGH MONDAY/...H5 TROUGH CONTINUES TO
DIVE ACROSS THE FOUR CORNERS REGION...WITH FLOW BUCKLING AHEAD OF
IT ACROSS THE SOUTHERN PLAINS. WITH WEAK DIFFLUENCE ALOFT AND
SHORTWAVES ROTATING AROUND THE SOUTHERN END OF THE
TROUGH...THUNDERSTORMS WILL LIKELY FIRE ALONG THE MOUNTAINS IN
MEXICO AND SWEEP ENE ACROSS THE RIO GRANDE PLAINS. THESE
THUNDERSTORMS WILL LIKELY BE STRONG...BUT STEERING FLOW WOULD
LIKELY CONFINE THESE STORMS TO ZAPATA COUNTY AND POINTS NORTH.
CHANCE POPS ALREADY IN FORECAST...WITH NO TWEAKING REQUIRED. SAME
SETUP PROGGED FOR FRIDAY...EXCEPT THE H5 TROUGH TO THE WEST IS
BEGINNING TO FILL IN...DECREASING THE DIFFLUENCE ALOFT.
THUNDERSTORMS WILL LIKELY STILL BE ABLE TO FIRE IN MEXICO...BUT
WILL HAVE MUCH HARDER TIME PROGRESSING ENE ACROSS THE RIO GRANDE.
MODELS ARE NOT AGREEING ON THE PROGRESSION OF THE NEXT TROUGH
DROPPING DOWN THE ROCKIES THIS WEEKEND. BOTH MODELS SHOW A COLD
FRONT MOVING INTO TEXAS THIS WEEKEND. THE MORE PROGRESSIVE PATTERN
WOULD STALL THE FRONT WELL TO THE NORTH...WHILE A TRAILING SLOWER
TROUGH WILL ALLOW THE FRONT INTO SOUTH TEXAS LATE IN THE WEEKEND
OR EARLY NEXT WEEK. WILL HOLD ONTO SLIGHT CHANCE POP FOR NOW FOR
THE CONSIDERABLE UNCERTAINTY IN THE FORECAST.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...HIGHER PRESSURE WILL PREVAIL TO THE
EAST...OVER THE WEST GULF...RESULTING IN LIGHT TO MODERATE SOUTHEAST
QUADRANT WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS OR TSTMS WILL
BE POSSIBLE AT TIMES.

THURSDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE FOR LATE
WEEK INTO THE WEEKEND AS SOUTHEASTERLY FLOW CONTINUES ACROSS THE
WESTERN GULF. SEAS WILL GENERALLY REMAIN IN THE 3 TO 4 FOOT
RANGE. SOME THUNDERSTORMS ACTIVITY IS POSSIBLE LATE THURSDAY
NIGHT WHICH MAY AGITATE SEAS SOMEWHAT...BUT WILL BE BRIEF IN
NATURE.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





000
FXUS64 KBRO 220603 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
103 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE LOW
AND MID LEVEL CLOUDS ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING.
CEILINGS RANGE FROM AROUND 1700 FEET AT MFE/APY AND T65 TO AROUND
3500 FEET AT BRO/HRL AND PIL. EXPECT MVFR CONDITIONS TO DEVELOP AT
ALL TAF SITES BY 09Z WITH IFR CONDITIONS POSSIBLE BEFORE SUNRISE
AT MFE AS LOW TO MID LEVEL MOISTURE INCREASES AND AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. MVFR CONDITIONS GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP ALONG THE
WEAK BOUNDARY AS IT MOVES NORTHWARD THIS AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 624 PM CDT TUE APR 21 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MID
LEVEL CLOUDS ACROSS THE CWA EARLY THIS EVENING. CEILINGS WERE NEAR
2600FT AT KMFE TO NEAR 3600FT AT KBKS. EXPECT MVFR CONDITIONS TO
DEVELOP THIS EVENING AND IFR CONDITIONS TO DEVELOP WED MORNING AS
LOW TO MID LEVEL MOISTURE INCREASES ACROSS THE RIO GRANDE VALLEY
AND THE NORTHERN RANCHLANDS TONIGHT INTO WEDNESDAY AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. ISOLATED SHOWERS WILL DEVELOP ALONG THIS BOUNDARY
AS IT MOVES NORTHWARD WED AFTERNOON.

PREV DISCUSSION... /ISSUED 249 PM CDT TUE APR 21 2015/
SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...HIGH PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY WITH WEAK H5 RIDGING JUST UPSTREAM AND AN
H5 LOW OVER SOUTHERN CALIFORNIA MOVING UNDER THE WEST COAST RIDGE.
A DEW POINT BOUNDARY HAS PUSHED NORTH OVER DEEP SOUTH TEXAS AND
HAS PROVIDED A FOCUS FOR WEAK ONGOING CONVECTION OVER THE AREA
TODAY.

WEAK ONSHORE FLOW SUPPORTED BY HIGH PRESSURE TO THE EAST WILL KEEP
LOW LEVEL MOISTURE ELEVATED. PWAT VALUES WILL STAY ABOVE 1.5 INCHES
THROUGH THE SHORT TERM. RAIN CHANCES WILL DIMINISH TONIGHT AS THE
INFLUENCE OF A RIGHT REAR ENTRANCE REGION OF THE SUBTROPICAL JET
REPOSITIONS AWAY FROM THE AREA. SATURATED LOWER LAYERS WILL SHRINK
IN DEPTH WHILE MILD CAPPING DEVELOPS. NONETHELESS...THE AREA WILL BE
UNDER A MARGINAL RISK OF SVR THUNDERSTORMS WEDNESDAY AS TEMPERATURES
WARM INTO THE MID AND UPPER 80S AND A WEAK SHORT WAVE MOVES THROUGH
THE FLOW ALOFT. OVERNIGHT LOW TEMPERATURES WILL BE WELL INTO THE 70S
TO MATCH THE ELEVATED DEW POINTS.

LONG TERM /THURSDAY THROUGH MONDAY/...H5 TROUGH CONTINUES TO
DIVE ACROSS THE FOUR CORNERS REGION...WITH FLOW BUCKLING AHEAD OF
IT ACROSS THE SOUTHERN PLAINS. WITH WEAK DIFFLUENCE ALOFT AND
SHORTWAVES ROTATING AROUND THE SOUTHERN END OF THE
TROUGH...THUNDERSTORMS WILL LIKELY FIRE ALONG THE MOUNTAINS IN
MEXICO AND SWEEP ENE ACROSS THE RIO GRANDE PLAINS. THESE
THUNDERSTORMS WILL LIKELY BE STRONG...BUT STEERING FLOW WOULD
LIKELY CONFINE THESE STORMS TO ZAPATA COUNTY AND POINTS NORTH.
CHANCE POPS ALREADY IN FORECAST...WITH NO TWEAKING REQUIRED. SAME
SETUP PROGGED FOR FRIDAY...EXCEPT THE H5 TROUGH TO THE WEST IS
BEGINNING TO FILL IN...DECREASING THE DIFFLUENCE ALOFT.
THUNDERSTORMS WILL LIKELY STILL BE ABLE TO FIRE IN MEXICO...BUT
WILL HAVE MUCH HARDER TIME PROGRESSING ENE ACROSS THE RIO GRANDE.
MODELS ARE NOT AGREEING ON THE PROGRESSION OF THE NEXT TROUGH
DROPPING DOWN THE ROCKIES THIS WEEKEND. BOTH MODELS SHOW A COLD
FRONT MOVING INTO TEXAS THIS WEEKEND. THE MORE PROGRESSIVE PATTERN
WOULD STALL THE FRONT WELL TO THE NORTH...WHILE A TRAILING SLOWER
TROUGH WILL ALLOW THE FRONT INTO SOUTH TEXAS LATE IN THE WEEKEND
OR EARLY NEXT WEEK. WILL HOLD ONTO SLIGHT CHANCE POP FOR NOW FOR
THE CONSIDERABLE UNCERTAINTY IN THE FORECAST.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...HIGHER PRESSURE WILL PREVAIL TO THE
EAST...OVER THE WEST GULF...RESULTING IN LIGHT TO MODERATE SOUTHEAST
QUADRANT WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS OR TSTMS WILL
BE POSSIBLE AT TIMES.

THURSDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE FOR LATE
WEEK INTO THE WEEKEND AS SOUTHEASTERLY FLOW CONTINUES ACROSS THE
WESTERN GULF. SEAS WILL GENERALLY REMAIN IN THE 3 TO 4 FOOT
RANGE. SOME THUNDERSTORMS ACTIVITY IS POSSIBLE LATE THURSDAY
NIGHT WHICH MAY AGITATE SEAS SOMEWHAT...BUT WILL BE BRIEF IN
NATURE.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63




000
FXUS64 KBRO 220603 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
103 AM CDT WED APR 22 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE LOW
AND MID LEVEL CLOUDS ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING.
CEILINGS RANGE FROM AROUND 1700 FEET AT MFE/APY AND T65 TO AROUND
3500 FEET AT BRO/HRL AND PIL. EXPECT MVFR CONDITIONS TO DEVELOP AT
ALL TAF SITES BY 09Z WITH IFR CONDITIONS POSSIBLE BEFORE SUNRISE
AT MFE AS LOW TO MID LEVEL MOISTURE INCREASES AND AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. MVFR CONDITIONS GRADUALLY IMPROVE MID TO LATE
MORNING WITH HIGH END MVFR TO LOW END VFR CONDITIONS EXPECTED AT
ALL TAF SITES BY 18Z. ISOLATED SHOWERS SHOULD DEVELOP ALONG THE
WEAK BOUNDARY AS IT MOVES NORTHWARD THIS AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 624 PM CDT TUE APR 21 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE MID
LEVEL CLOUDS ACROSS THE CWA EARLY THIS EVENING. CEILINGS WERE NEAR
2600FT AT KMFE TO NEAR 3600FT AT KBKS. EXPECT MVFR CONDITIONS TO
DEVELOP THIS EVENING AND IFR CONDITIONS TO DEVELOP WED MORNING AS
LOW TO MID LEVEL MOISTURE INCREASES ACROSS THE RIO GRANDE VALLEY
AND THE NORTHERN RANCHLANDS TONIGHT INTO WEDNESDAY AS A WEAK
STATIONARY FRONTAL BOUNDARY ACROSS THE WESTERN GULF OF MEXICO
LIFTS NORTHWARD. ISOLATED SHOWERS WILL DEVELOP ALONG THIS BOUNDARY
AS IT MOVES NORTHWARD WED AFTERNOON.

PREV DISCUSSION... /ISSUED 249 PM CDT TUE APR 21 2015/
SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...HIGH PRESSURE OVER THE
LOWER MISSISSIPPI VALLEY WITH WEAK H5 RIDGING JUST UPSTREAM AND AN
H5 LOW OVER SOUTHERN CALIFORNIA MOVING UNDER THE WEST COAST RIDGE.
A DEW POINT BOUNDARY HAS PUSHED NORTH OVER DEEP SOUTH TEXAS AND
HAS PROVIDED A FOCUS FOR WEAK ONGOING CONVECTION OVER THE AREA
TODAY.

WEAK ONSHORE FLOW SUPPORTED BY HIGH PRESSURE TO THE EAST WILL KEEP
LOW LEVEL MOISTURE ELEVATED. PWAT VALUES WILL STAY ABOVE 1.5 INCHES
THROUGH THE SHORT TERM. RAIN CHANCES WILL DIMINISH TONIGHT AS THE
INFLUENCE OF A RIGHT REAR ENTRANCE REGION OF THE SUBTROPICAL JET
REPOSITIONS AWAY FROM THE AREA. SATURATED LOWER LAYERS WILL SHRINK
IN DEPTH WHILE MILD CAPPING DEVELOPS. NONETHELESS...THE AREA WILL BE
UNDER A MARGINAL RISK OF SVR THUNDERSTORMS WEDNESDAY AS TEMPERATURES
WARM INTO THE MID AND UPPER 80S AND A WEAK SHORT WAVE MOVES THROUGH
THE FLOW ALOFT. OVERNIGHT LOW TEMPERATURES WILL BE WELL INTO THE 70S
TO MATCH THE ELEVATED DEW POINTS.

LONG TERM /THURSDAY THROUGH MONDAY/...H5 TROUGH CONTINUES TO
DIVE ACROSS THE FOUR CORNERS REGION...WITH FLOW BUCKLING AHEAD OF
IT ACROSS THE SOUTHERN PLAINS. WITH WEAK DIFFLUENCE ALOFT AND
SHORTWAVES ROTATING AROUND THE SOUTHERN END OF THE
TROUGH...THUNDERSTORMS WILL LIKELY FIRE ALONG THE MOUNTAINS IN
MEXICO AND SWEEP ENE ACROSS THE RIO GRANDE PLAINS. THESE
THUNDERSTORMS WILL LIKELY BE STRONG...BUT STEERING FLOW WOULD
LIKELY CONFINE THESE STORMS TO ZAPATA COUNTY AND POINTS NORTH.
CHANCE POPS ALREADY IN FORECAST...WITH NO TWEAKING REQUIRED. SAME
SETUP PROGGED FOR FRIDAY...EXCEPT THE H5 TROUGH TO THE WEST IS
BEGINNING TO FILL IN...DECREASING THE DIFFLUENCE ALOFT.
THUNDERSTORMS WILL LIKELY STILL BE ABLE TO FIRE IN MEXICO...BUT
WILL HAVE MUCH HARDER TIME PROGRESSING ENE ACROSS THE RIO GRANDE.
MODELS ARE NOT AGREEING ON THE PROGRESSION OF THE NEXT TROUGH
DROPPING DOWN THE ROCKIES THIS WEEKEND. BOTH MODELS SHOW A COLD
FRONT MOVING INTO TEXAS THIS WEEKEND. THE MORE PROGRESSIVE PATTERN
WOULD STALL THE FRONT WELL TO THE NORTH...WHILE A TRAILING SLOWER
TROUGH WILL ALLOW THE FRONT INTO SOUTH TEXAS LATE IN THE WEEKEND
OR EARLY NEXT WEEK. WILL HOLD ONTO SLIGHT CHANCE POP FOR NOW FOR
THE CONSIDERABLE UNCERTAINTY IN THE FORECAST.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...HIGHER PRESSURE WILL PREVAIL TO THE
EAST...OVER THE WEST GULF...RESULTING IN LIGHT TO MODERATE SOUTHEAST
QUADRANT WINDS AND LOW TO MODERATE SEAS. A FEW SHOWERS OR TSTMS WILL
BE POSSIBLE AT TIMES.

THURSDAY THROUGH SUNDAY...CONSISTENT CONDITIONS CONTINUE FOR LATE
WEEK INTO THE WEEKEND AS SOUTHEASTERLY FLOW CONTINUES ACROSS THE
WESTERN GULF. SEAS WILL GENERALLY REMAIN IN THE 3 TO 4 FOOT
RANGE. SOME THUNDERSTORMS ACTIVITY IS POSSIBLE LATE THURSDAY
NIGHT WHICH MAY AGITATE SEAS SOMEWHAT...BUT WILL BE BRIEF IN
NATURE.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

63





    US Dept of Commerce
    National Oceanic and Atmospheric Administration
    National Weather Service
    1325 East West Highway
    Silver Spring, MD 20910
    Page Author: NWS Internet Services Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities