[top]
000
FXUS63 KGID 210451
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1151 PM CDT SUN MAY 20 2012
.AVIATION...06Z KGRI TAF. THE WIND WILL BE LIGHT AND VARIABLE THROUGH
THE NIGHT. THERE WILL BE AN INCREASE IN THE SOUTHEASTERLY WIND BY
MID MORNING BUT NOTHING TOO GUSTY. VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE PERIOD. THERE WILL BE FEW TO SCATTERED HIGH CLOUDS
BUT THERE SHOULD BE NO WEATHER RELATED AVIATION CONCERNS.
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT SUN MAY 20 2012/
SHORT TERM...TONIGHT THROUGH TOMORROW.
BEEN A PLEASANT DAY ACROSS THE CWA...WITH SATELLITE AND UPPER AIR
PROFILER DATA SHOWING THE REGION WITH SLIGHT NORTHWESTERLY FLOW
SET UP...AS THE SYSTEM WHICH BROUGHT US SEVERE WEATHER YESTERDAY
CONTINUES TO SHIFT EAST /AFFECTING THE WRN GREAT LAKES AND SOUTH
TOWARD THE GULF/ AND BROAD RIDGING BUILDS ACROSS THE ROCKIES.
OTHER THAN A BIT OF FAIR WX CU IN THE EAST AND MID LEVEL CLOUDS
MOVING INTO THE WEST...SKIES HAVE BEEN SUNNY. WINDS HAVE REMAINED
NORTHERLY THROUGH THE DAY...WITH HIGH PRESSURE CENTERED JUST OFF
TO THE WEST...BUT CONTINUES TO SLIDE EAST ACROSS NEB. STILL SEEING
SOME GUSTS THIS AFTERNOON...ESP ACROSS CENTRAL/ERN PORTIONS OF THE
CWA.
LOOKING AT TONIGHT AND THROUGH TOMORROW...THE INHERITED DRY
FORECAST REMAINS IN PLACE. WILL HAVE TO CONTINUE TO KEEP AN EYE
ON LATE TONIGHT/EARLY TOMORROW MORNING...AS MODELS CONTINUE TO
SHOW A SRLY LLJ DEVELOPING ALONG THE HIGH PLAINS TONIGHT AND
GRADUALLY SLIDING EAST...WITH AN ACCOMPANYING AREA OF INCREASED
WAA/THETAE ADVECTION. KEPT THE FORECAST DRY AS THERE HAS BEEN
LITTLE CHANGE IN MODELS KEEPING THIS FEATURE AND ASSOCIATED QPF
PRIMARILY TO THE NW OF THE CWA...BUT IT COULD BE CLOSE IN THE NW
CORNER OF THE CWA. OTHERWISE...THE UPPER LEVEL PATTERN ACROSS THE
CONUS AND NORTHWESTERLY FLOW OVER THE REGION BECOMES SLIGHTLY MORE
AMPLIFIED THROUGH THE SHORT TERM PERIOD...AS TROUGHING AFFECTS THE
ERN CONUS AND RIDGING BUILDS FURTHER NORTH INTO THE ROCKIES.
AT THE SURFACE...HIGH PRESSURE REMAINS A PRIMARY PLAYER...AND WILL
CONTINUE ITS EASTWARD SLIDE THIS EVENING AND OVERNIGHT...WITH
MODELS IN GOOD AGREEMENT SHOWING IT ROUGHLY CENTERED OVER THE
ERN NEB/KS STATE LINE. THIS WILL BRING FAIRLY LIGHT WIND
SPEEDS...WITH A GRADUAL TURN TO THE EAST THEN SOUTHEAST. SPEEDS
WILL BE ON THE INCREASE DURING THE DAY TOMORROW AS THE PRESSURE
GRADIENT TIGHTENS UP AS LOW PRESSURE DEVELOPS OVER THE ROCKIES.
EXPECTING A SLIGHT E/W GRADIENT IN TEMPERATURES TOMORROW WITH THE
EAST REMAINING UNDER THE INFLUENCE OF THE SFC HIGH LONGER INTO THE
DAY...FORECAST HIGHS RANGE FROM THE MID/UPPER 70S IN THE EAST TO
LOWER 80S IN THE WEST.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. CHANCES OF PRECIPITATION
WILL BE A BIT OF A TOUGH CALL FROM WEDNESDAY THROUGH SUNDAY.
WE WILL KICK OFF MONDAY NIGHT WITH A SHORTWAVE UPPER LEVEL RIDGE
CONTINUING TO MOVE EAST INTO THE HIGH PLAINS. THIS WILL KEEP
CONDITIONS DRY. AT THE SAME TIME...A BROAD LONGWAVE TROUGH MAKES
ITS WAY INTO THE PACIFIC NORTHWEST.
TUESDAY IS SHAPING UP TO BE THE WARMEST DAY OF THE LONG TERM
FORECAST WITH A SURFACE TROUGH IN THE LEE OF THE ROCKY MOUNTAINS
INCREASING IN INTENSITY. WIND SPEEDS WILL ALSO INCREASE DUE TO THE
TIGHTENING OF THE SURFACE PRESSURE GRADIENT. ALTHOUGH TUESDAY
SHOULD BE WINDY...MODEL SOLUTIONS ARE BACKING OFF OF WIND SPEEDS
A BIT COMPARED TO SOLUTIONS FROM YESTERDAY AND THIS DOES NOT
APPEAR TO BE THE SOLID WIND ADVISORY THAT IT LOOKED LIKE
YESTERDAY. WIND SPEEDS STILL LOOK LIKE THEY WILL BE STRONGER IN
THE WESTERN CWA. 850 MB TEMPERATURES INDICATE HOTTER
WEATHER...INTO THE UPPER 80S AND LOWER 90S...BEING A BIT WARMER TO
THE WEST. WE COULD GET A WARM FRONT TO POKE INTO THE WESTERN CWA
BY TUESDAY AFTERNOON BUT CAPPING SHOULD BE STRONG....SO I AM NOT
ANTICIPATING ANY CONVECTION BREAKING OUT TUESDAY AFTERNOON DESPITE
THE POTENTIAL FOCUS OF THE WARM FRONT. THE INFLUENCE OF THE RIDGE
WILL GIVE US ONE MORE DRY NIGHT BEFORE A SHIFT OCCURS IN THE
PATTERN.
BY WEDNESDAY...THE AFOREMENTIONED LONGWAVE TROUGH SETTLES INTO THE
NORTHWESTERN UNITED STATES AND PUSHES AN ASSOCIATED COLD FRONT
SOUTHEAST THROUGH MUCH OF THE CWA BY WEDNESDAY AFTERNOON. MODELS
ARE TRENDING FASTER WITH THIS PUSH...WITH THE COLD FRONT
PROBABLY STILL DRAPED ACROSS THE SOUTHEASTERN CWA BY TUESDAY
AFTERNOON. WE SHOULD BE CAPPED ENOUGH TO PREVENT CONVECTION FROM
DEVELOPING WEDNESDAY AFTERNOON. THE FRONT HAS BEEN LONG ADVERTISED
TO STALL BY WEDNESDAY EVENING...BUT AGAIN...THIS WILL BE FARTHER
SOUTH THAN PREVIOUS RUNS OF MODELS. AS A LOW-LEVEL JET
DEVELOPS...THIS WILL ENCOURAGE NOCTURNAL CONVECTION...WHICH COULD
BE STRONG TO SEVERE GIVEN THE EXPECTED SEVERE PARAMETERS. IN
FACT...THE SCENARIO OF DRY WEATHER DURING THE DAY WHEN WE ARE
CAPPED AND THEN A SHOT AT NOCTURNAL ELEVATED CONVECTION WHEN THE
CAP BREAKS DOWN WILL BE THE PREDICTED WEATHER FOR MOST OF THE REST
OF THE LONG TERM FORECAST AS THE BOUNDARY HANGS AROUND AND
EVENTUALLY MOVES NORTH. FOR NOW IT APPEARS THAT RAIN/THUNDERSTORM
CHANCES WILL BE GENERALLY MORE TO THE NORTH WHERE THE BETTER LOW-
LEVEL NIGHT TIME CONVERGENCE WILL BE. ALSO...THESE NOCTURNAL
STORMS CAN ONCE AGAIN BE STRONG TO SEVERE EACH NIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
[top]
000
FXUS63 KOAX 210449
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1150 PM CDT SUN MAY 20 2012
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDS ARE EXPECTED THROUGH THE PERIOD.
&&
.DISCUSSION...
HIGH PRESSURE WAS LOCATED OVER THE REGION AT 19Z WITH COLD FRONT
PUSHING SOUTHEAST INTO THE MID MISSISSIPPI VALLEY. THIS AREA OF
HIGH PRESSURE WILL SLIDE SLOWLY EAST TONIGHT THROUGH MONDAY NIGHT
AS LOW PRESSURE DEVELOPS OVER THE MONTANA HIGH PLAINS. ON TUESDAY
THE LOW BEGINS TO MOVE EAST PULLING A COLD FRONT INTO THE WESTERN
HIGH PLAINS AND MUCH WARMER TEMPERATURES INTO THE CENTRAL PLAINS.
THE COLD FRONT THEN MOVES INTO THE CENTRAL PLAINS TUESDAY NIGHT
AND WEDNESDAY WITH SOME CHANCE OF THUNDERSTORMS BUT LOOKS FOR NOW
LIKE BETTER MOISTURE AND DYNAMICS WILL BE TO THE NORTH OF THE
AREA.
THIS FRONTAL BOUNDARY WILL CONTINUE TO BE A FACTOR IN THE EXTENDED
PERIOD AS IT STALLS ACROSS NORTHEAST KANSAS AND NORTHERN MISSOURI
WITH A CONTINUED CHANCE OF STORMS ALONG AND NORTH OF THE BOUNDARY
THURSDAY THROUGH FRIDAY. AFTER THIS THE GFS AND EURO CONTINUE TO
SHOW DIFFERENT SOLUTIONS IN TIMING ON MOVING THE FRONT NORTH AS
UPPER RIDGE BUILDS INTO THE UPPER MISSISSIPPI VALLEY. PRETTY MUCH
SPLIT THE DIFFERENCE FOR NOW DURING THE LATER PART OF THE EXTENDED
DUE TO THE UNCERTAINTY BETWEEN THE MODELS. MAY HAVE TO BOOST HIGH
TEMPERATURES DURING THIS TIME IN LATER FORECASTS IF EURO TURNS OUT
TO BE CORRECT WITH ITS STRONG RIDGING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KGID 202348
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
648 PM CDT SUN MAY 20 2012
.AVIATION...00Z KGRI TAF. THE WIND WILL BE LIGHT THROUGH THE NIGHT
AND GRADUALLY SHIFT FROM NORTHEAST EARLY THIS EVENING TO SOUTHEAST
BY DAWN. THERE WILL BE AN INCREASE IN THE SOUTHEASTERLY WIND BY
MID MORNING BUT NOTHING TOO GUSTY. VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE PERIOD. THERE WILL BE A FEW TO SCATTERED HIGH
CLOUDS BUT NOTHING THAT WILL CAUSE ANY PROBLEMS.
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT SUN MAY 20 2012/
SHORT TERM...TONIGHT THROUGH TOMORROW.
BEEN A PLEASANT DAY ACROSS THE CWA...WITH SATELLITE AND UPPER AIR
PROFILER DATA SHOWING THE REGION WITH SLIGHT NORTHWESTERLY FLOW
SET UP...AS THE SYSTEM WHICH BROUGHT US SEVERE WEATHER YESTERDAY
CONTINUES TO SHIFT EAST /AFFECTING THE WRN GREAT LAKES AND SOUTH
TOWARD THE GULF/ AND BROAD RIDGING BUILDS ACROSS THE ROCKIES.
OTHER THAN A BIT OF FAIR WX CU IN THE EAST AND MID LEVEL CLOUDS
MOVING INTO THE WEST...SKIES HAVE BEEN SUNNY. WINDS HAVE REMAINED
NORTHERLY THROUGH THE DAY...WITH HIGH PRESSURE CENTERED JUST OFF
TO THE WEST...BUT CONTINUES TO SLIDE EAST ACROSS NEB. STILL SEEING
SOME GUSTS THIS AFTERNOON...ESP ACROSS CENTRAL/ERN PORTIONS OF THE
CWA.
LOOKING AT TONIGHT AND THROUGH TOMORROW...THE INHERITED DRY
FORECAST REMAINS IN PLACE. WILL HAVE TO CONTINUE TO KEEP AN EYE
ON LATE TONIGHT/EARLY TOMORROW MORNING...AS MODELS CONTINUE TO
SHOW A SRLY LLJ DEVELOPING ALONG THE HIGH PLAINS TONIGHT AND
GRADUALLY SLIDING EAST...WITH AN ACCOMPANYING AREA OF INCREASED
WAA/THETAE ADVECTION. KEPT THE FORECAST DRY AS THERE HAS BEEN
LITTLE CHANGE IN MODELS KEEPING THIS FEATURE AND ASSOCIATED QPF
PRIMARILY TO THE NW OF THE CWA...BUT IT COULD BE CLOSE IN THE NW
CORNER OF THE CWA. OTHERWISE...THE UPPER LEVEL PATTERN ACROSS THE
CONUS AND NORTHWESTERLY FLOW OVER THE REGION BECOMES SLIGHTLY MORE
AMPLIFIED THROUGH THE SHORT TERM PERIOD...AS TROUGHING AFFECTS THE
ERN CONUS AND RIDGING BUILDS FURTHER NORTH INTO THE ROCKIES.
AT THE SURFACE...HIGH PRESSURE REMAINS A PRIMARY PLAYER...AND WILL
CONTINUE ITS EASTWARD SLIDE THIS EVENING AND OVERNIGHT...WITH
MODELS IN GOOD AGREEMENT SHOWING IT ROUGHLY CENTERED OVER THE
ERN NEB/KS STATE LINE. THIS WILL BRING FAIRLY LIGHT WIND
SPEEDS...WITH A GRADUAL TURN TO THE EAST THEN SOUTHEAST. SPEEDS
WILL BE ON THE INCREASE DURING THE DAY TOMORROW AS THE PRESSURE
GRADIENT TIGHTENS UP AS LOW PRESSURE DEVELOPS OVER THE ROCKIES.
EXPECTING A SLIGHT E/W GRADIENT IN TEMPERATURES TOMORROW WITH THE
EAST REMAINING UNDER THE INFLUENCE OF THE SFC HIGH LONGER INTO THE
DAY...FORECAST HIGHS RANGE FROM THE MID/UPPER 70S IN THE EAST TO
LOWER 80S IN THE WEST.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. CHANCES OF PRECIPITATION
WILL BE A BIT OF A TOUGH CALL FROM WEDNESDAY THROUGH SUNDAY.
WE WILL KICK OFF MONDAY NIGHT WITH A SHORTWAVE UPPER LEVEL RIDGE
CONTINUING TO MOVE EAST INTO THE HIGH PLAINS. THIS WILL KEEP
CONDITIONS DRY. AT THE SAME TIME...A BROAD LONGWAVE TROUGH MAKES
ITS WAY INTO THE PACIFIC NORTHWEST.
TUESDAY IS SHAPING UP TO BE THE WARMEST DAY OF THE LONG TERM
FORECAST WITH A SURFACE TROUGH IN THE LEE OF THE ROCKY MOUNTAINS
INCREASING IN INTENSITY. WIND SPEEDS WILL ALSO INCREASE DUE TO THE
TIGHTENING OF THE SURFACE PRESSURE GRADIENT. ALTHOUGH TUESDAY
SHOULD BE WINDY...MODEL SOLUTIONS ARE BACKING OFF OF WIND SPEEDS
A BIT COMPARED TO SOLUTIONS FROM YESTERDAY AND THIS DOES NOT
APPEAR TO BE THE SOLID WIND ADVISORY THAT IT LOOKED LIKE
YESTERDAY. WIND SPEEDS STILL LOOK LIKE THEY WILL BE STRONGER IN
THE WESTERN CWA. 850 MB TEMPERATURES INDICATE HOTTER
WEATHER...INTO THE UPPER 80S AND LOWER 90S...BEING A BIT WARMER TO
THE WEST. WE COULD GET A WARM FRONT TO POKE INTO THE WESTERN CWA
BY TUESDAY AFTERNOON BUT CAPPING SHOULD BE STRONG....SO I AM NOT
ANTICIPATING ANY CONVECTION BREAKING OUT TUESDAY AFTERNOON DESPITE
THE POTENTIAL FOCUS OF THE WARM FRONT. THE INFLUENCE OF THE RIDGE
WILL GIVE US ONE MORE DRY NIGHT BEFORE A SHIFT OCCURS IN THE
PATTERN.
BY WEDNESDAY...THE AFOREMENTIONED LONGWAVE TROUGH SETTLES INTO THE
NORTHWESTERN UNITED STATES AND PUSHES AN ASSOCIATED COLD FRONT
SOUTHEAST THROUGH MUCH OF THE CWA BY WEDNESDAY AFTERNOON. MODELS
ARE TRENDING FASTER WITH THIS PUSH...WITH THE COLD FRONT
PROBABLY STILL DRAPED ACROSS THE SOUTHEASTERN CWA BY TUESDAY
AFTERNOON. WE SHOULD BE CAPPED ENOUGH TO PREVENT CONVECTION FROM
DEVELOPING WEDNESDAY AFTERNOON. THE FRONT HAS BEEN LONG ADVERTISED
TO STALL BY WEDNESDAY EVENING...BUT AGAIN...THIS WILL BE FARTHER
SOUTH THAN PREVIOUS RUNS OF MODELS. AS A LOW-LEVEL JET
DEVELOPS...THIS WILL ENCOURAGE NOCTURNAL CONVECTION...WHICH COULD
BE STRONG TO SEVERE GIVEN THE EXPECTED SEVERE PARAMETERS. IN
FACT...THE SCENARIO OF DRY WEATHER DURING THE DAY WHEN WE ARE
CAPPED AND THEN A SHOT AT NOCTURNAL ELEVATED CONVECTION WHEN THE
CAP BREAKS DOWN WILL BE THE PREDICTED WEATHER FOR MOST OF THE REST
OF THE LONG TERM FORECAST AS THE BOUNDARY HANGS AROUND AND
EVENTUALLY MOVES NORTH. FOR NOW IT APPEARS THAT RAIN/THUNDERSTORM
CHANCES WILL BE GENERALLY MORE TO THE NORTH WHERE THE BETTER LOW-
LEVEL NIGHT TIME CONVERGENCE WILL BE. ALSO...THESE NOCTURNAL
STORMS CAN ONCE AGAIN BE STRONG TO SEVERE EACH NIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
[top]
000
FXUS63 KLBF 202335
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
635 PM CDT SUN MAY 20 2012
.AVIATION...
THUNDERSTORMS OVER THE NEBRASKA PANHANDLE WILL DISSIPATE THROUGH THE
EVENING. A MID CLOUD DECK WILL MOVE ACROSS WESTERN NEBRASKA
OVERNIGHT. LIGHT AND VARIABLE WINDS WILL BECOME SOUTHERLY AND
INCREASE OVERNIGHT WITH SOUTHERLY FLOW OVER WESTERN NEBRASKA ON
MONDAY AT 10 TO 20 WITH HIGHER GUSTS. VISUAL FLIGHT RULES EXPECTED
THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 332 PM CDT SUN MAY 20 2012/
DISCUSSION...
A WEAK UPPER LEVEL DISTURBANCE ACROSS ERN WY AND RETURN MOISTURE UP
THE HIGH PLAINS MAY BE SUFFICIENT TO CARRY ISOLATED TSTMS EAST AND
SOUTHEAST THROUGH SWRN NEB THIS EVENING. THE NAM AND GFS SUGGEST
ANOTHER WEAK AREA OF CONVECTION DEVELOPING ACROSS NCNTL NEB LATER
TONIGHT AS THE LOW LEVEL JET STRENGTHENS. SEVERE WEATHER CONCERNS
REVOLVE AROUND LARGE HAIL BUT SHEAR PROFILES WHICH ARE QUITE STRONG
SUGGEST THE UPDRAFTS ACROSS SERN WY THIS AFTN ARE BEING RIPPED
APART. THUS UPDRAFT STRENGTH MAY BE INSUFFICIENT TO MAINTAIN STORM
DEVELOPMENT.
ON MONDAY...MOISTURE AND SOUTH WINDS INCREASE TO 20 TO 30 MPH. THE
CONSENSUS IS FOR LOW PRESSURE TO DEEPEN ACROSS SERN MT WITH A WARM
FRONTAL ARM EXTENDING SOUTHEAST THROUGH NCNTL NEB. NAM12 K INDICES
INCREASE TO NEAR 40C. THE ENSUING DRYLINE BULGE AND MOIST TONGUE
MONDAY AFTERNOON MAY SPARK ISOLATED STRONG OR SEVERE THUNDERSTORMS.
SINCE IT IS THE LATE MAY THERES REALLY NO SENSE DISCRIMINATING
BETWEEN SEVERE AND NON SEVERE STORMS. ANYTHING THAT FORMS COULD
BECOME SEVERE. THIS ACTIVITY SHOULD DIMINISH AROUND SUNSET AND THE
DRYLINE SHOULD RETREAT WEST OF HIGHWAY 61.
VERY WARM WEATHER IS EXPECTED TUESDAY. THE DRYLINE WILL SURGE
FARTHER EAST TOWARD KVTN AND NORTHWEST NEB WILL TORCH OUT IN THE
MID 90S. THE ECM REALLY SHARPENS THE DRYLINE AND ALTHOUGH 700MB
TEMPS WILL RISE TOWARD 12C A SMALL AREA OF NRN CHERRY COUNTY MIGHT
SEE AN ISOLATED TSTM. A FAIRLY DEEP SOUTHERLY FLOW DEVELOPS BELOW
800 MB WHICH SHOULD HOLD TEMPS IN THE 80S ALONG AND EAST OF
HIGHWAY 183. WEST OF 183...SKIES THE LIMIT LITERALLY AS MIXING
HEIGHTS WILL DETERMINE MAX TEMPS. HIGHS IN THE LOW TO MID 90S LOOK
REASONABLE. MEANWHILE LOW PRESSURE WILL DEEPEN TO AROUND 990 MB
ACROSS CNTL SD AND SOUTH WINDS SHOULD INCREASE TO AROUND 30 MPH
ALONG AND EAST OF HIGHWAY 83.
A COLD FRONT WILL DROP THROUGH TUESDAY NIGHT. ALL MODELS INDICATE
A 700MB THERMAL RIDGE WILL SEND 700MB TEMPS TO 14-15C AND CAP TSTM
DEVELOPMENT ALL AREAS EXCEPT PERHAPS THE FAR NORTHEAST.
LOW PRESSURE WILL SETTLE ACROSS SERN COLO WEDNESDAY AFTERNOON WITH
THETA E ADVECTION NORTH OF THE FRONT ACROSS WRN/NCNTL NEB. ALL
MODELS INDICATE STRONG WINDS ALOFT SUFFICIENT FOR SEVERE STORM
DEVELOPMENT. THE CONSENSUS IS FOR STORMS TO FIRE ACROSS NORTHWEST
NEB LATE IN THE DAY WHICH SHOULD DEVELOP EAST AND SOUTHEAST AS AN
ORGANIZED MCS. SFC LOW PRESSURE ACROSS ERN COLO WILL TRACK EAST
ALONG OR NEAR THE NEB-KS BORDER OVERNIGHT.
THURSDAY THROUGH SUNDAY...
MODELS STILL AGREE THAT A LARGE TROUGH WILL BECOME ESTABLISHED
ACROSS THE WESTERN CONUS...WHILE A SPRAWLING UPPER LEVEL HIGH
PRESSURE SYSTEM DEVELOPS ACROSS THE EASTERN CONUS. THIS PUTS OUR
AREA SOMEWHERE IN THE MIDDLE. THE TREND TODAY IN BOTH THE
OPERATIONAL AND ENSEMBLE SOLUTIONS...IS TO KEEP THE UPPER LEVEL HIGH
A LITTLE FARTHER EAST ACROSS THE TENNESSEE VALLEY REGION...AND
DEVELOP THE WEST COAST TROUGH FARTHER EAST. THE SLIGHT SHIFT
EASTWARD SHIFT OF THESE FEATURES WOULD ALLOW FOR SOMEWHAT BETTER
GULF MOISTURE RETURN INTO THE PLAINS. ALSO...MID LEVEL TEMPERATURES
WOULD BE SLIGHTLY COOLER...AND MEAN BETTER CHANCES FOR T-STORMS.
WHILE HIGH TEMPERATURES STILL APPEAR THEY WILL BE VERY WARM DURING
THE WEEKEND...WE MAY NOT SEE HOT TEMPERATURES LIKE SOME OF THE
OPERATIONAL MODELS WHERE HINTING AT YESTERDAY.
FOR NOW...THE BEST APPROACH TO THE FORECAST IS TO GRADUALLY RAISE
HIGHS FROM THE UPPER 70S THURSDAY...TO THE MID AND UPPER 80S
SATURDAY AND SUNDAY. AT THIS TIME WILL CONTINUE SOME LOW CHANCE AND
SLIGHT CHANCE POPS DUE TO AMPLE INSTABILITY...AND THE TREND TOWARD A
LITTLE COOLER MID LEVEL TEMPS.
AVIATION...
MAINLY CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HRS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. AS HIGH PRESSURE
DOMINATES. AS THE HIGH DRIFTS EAST TONIGHT...SOUTH TO SOUTHEAST
WINDS OF 5 TO 10 KTS CAN BE EXPECTED ON THE BACKSIDE OF THE
HIGH...INCREASING TO 10 TO 20 KTS DURING THE DAY MONDAY.
FIRE WEATHER...
VERY DRY AIR WILL SPREAD INTO THE NEBRASKA PANHANDLE MONDAY AND
TUESDAY IN RESPONSE TO DEEPENING LOW PRESSURE ACROSS THE NRN
PLAINS. WIND GUSTS IN EXCESS OF 30 MPH ARE LIKELY ACROSS THE ERN
PANHANDLE AND WRN NEB. IF THE DRYLINE SHARPENS UP AS FCST BY SOME
MODELS...CRITICAL FIRE DANGER MAY DEVELOP. THIS IS MOSTLY LIKELY
TUESDAY AFTN AND THE DRYLINE BEHAVIOR MONDAY WILL PROVIDE A
BASELINE FOR TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
000
FXUS63 KOAX 202329
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
628 PM CDT SUN MAY 20 2012
.AVIATION...
00Z TAFS FOR KOMA...KOFK...KLNK
VFR CONDS ARE EXPECTED THROUGH THE PERIOD.
&&
.DISCUSSION...
HIGH PRESSURE WAS LOCATED OVER THE REGION AT 19Z WITH COLD FRONT
PUSHING SOUTHEAST INTO THE MID MISSISSIPPI VALLEY. THIS AREA OF
HIGH PRESSURE WILL SLIDE SLOWLY EAST TONIGHT THROUGH MONDAY NIGHT
AS LOW PRESSURE DEVELOPS OVER THE MONTANA HIGH PLAINS. ON TUESDAY
THE LOW BEGINS TO MOVE EAST PULLING A COLD FRONT INTO THE WESTERN
HIGH PLAINS AND MUCH WARMER TEMPERATURES INTO THE CENTRAL PLAINS.
THE COLD FRONT THEN MOVES INTO THE CENTRAL PLAINS TUESDAY NIGHT
AND WEDNESDAY WITH SOME CHANCE OF THUNDERSTORMS BUT LOOKS FOR NOW
LIKE BETTER MOISTURE AND DYNAMICS WILL BE TO THE NORTH OF THE
AREA.
THIS FRONTAL BOUNDARY WILL CONTINUE TO BE A FACTOR IN THE EXTENDED
PERIOD AS IT STALLS ACROSS NORTHEAST KANSAS AND NORTHERN MISSOURI
WITH A CONTINUED CHANCE OF STORMS ALONG AND NORTH OF THE BOUNDARY
THURSDAY THROUGH FRIDAY. AFTER THIS THE GFS AND EURO CONTINUE TO
SHOW DIFFERENT SOLUTIONS IN TIMING ON MOVING THE FRONT NORTH AS
UPPER RIDGE BUILDS INTO THE UPPER MISSISSIPPI VALLEY. PRETTY MUCH
SPLIT THE DIFFERENCE FOR NOW DURING THE LATER PART OF THE EXTENDED
DUE TO THE UNCERTAINTY BETWEEN THE MODELS. MAY HAVE TO BOOST HIGH
TEMPERATURES DURING THIS TIME IN LATER FORECASTS IF EURO TURNS OUT
TO BE CORRECT WITH ITS STRONG RIDGING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KGID 202048
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
348 PM CDT SUN MAY 20 2012
.SHORT TERM...TONIGHT THROUGH TOMORROW.
BEEN A PLEASANT DAY ACROSS THE CWA...WITH SATELLITE AND UPPER AIR
PROFILER DATA SHOWING THE REGION WITH SLIGHT NORTHWESTERLY FLOW
SET UP...AS THE SYSTEM WHICH BROUGHT US SEVERE WEATHER YESTERDAY
CONTINUES TO SHIFT EAST /AFFECTING THE WRN GREAT LAKES AND SOUTH
TOWARD THE GULF/ AND BROAD RIDGING BUILDS ACROSS THE ROCKIES.
OTHER THAN A BIT OF FAIR WX CU IN THE EAST AND MID LEVEL CLOUDS
MOVING INTO THE WEST...SKIES HAVE BEEN SUNNY. WINDS HAVE REMAINED
NORTHERLY THROUGH THE DAY...WITH HIGH PRESSURE CENTERED JUST OFF
TO THE WEST...BUT CONTINUES TO SLIDE EAST ACROSS NEB. STILL SEEING
SOME GUSTS THIS AFTERNOON...ESP ACROSS CENTRAL/ERN PORTIONS OF THE
CWA.
LOOKING AT TONIGHT AND THROUGH TOMORROW...THE INHERITED DRY
FORECAST REMAINS IN PLACE. WILL HAVE TO CONTINUE TO KEEP AN EYE
ON LATE TONIGHT/EARLY TOMORROW MORNING...AS MODELS CONTINUE TO
SHOW A SRLY LLJ DEVELOPING ALONG THE HIGH PLAINS TONIGHT AND
GRADUALLY SLIDING EAST...WITH AN ACCOMPANYING AREA OF INCREASED
WAA/THETAE ADVECTION. KEPT THE FORECAST DRY AS THERE HAS BEEN
LITTLE CHANGE IN MODELS KEEPING THIS FEATURE AND ASSOCIATED QPF
PRIMARILY TO THE NW OF THE CWA...BUT IT COULD BE CLOSE IN THE NW
CORNER OF THE CWA. OTHERWISE...THE UPPER LEVEL PATTERN ACROSS THE
CONUS AND NORTHWESTERLY FLOW OVER THE REGION BECOMES SLIGHTLY MORE
AMPLIFIED THROUGH THE SHORT TERM PERIOD...AS TROUGHING AFFECTS THE
ERN CONUS AND RIDGING BUILDS FURTHER NORTH INTO THE ROCKIES.
AT THE SURFACE...HIGH PRESSURE REMAINS A PRIMARY PLAYER...AND WILL
CONTINUE ITS EASTWARD SLIDE THIS EVENING AND OVERNIGHT...WITH
MODELS IN GOOD AGREEMENT SHOWING IT ROUGHLY CENTERED OVER THE
ERN NEB/KS STATE LINE. THIS WILL BRING FAIRLY LIGHT WIND
SPEEDS...WITH A GRADUAL TURN TO THE EAST THEN SOUTHEAST. SPEEDS
WILL BE ON THE INCREASE DURING THE DAY TOMORROW AS THE PRESSURE
GRADIENT TIGHTENS UP AS LOW PRESSURE DEVELOPS OVER THE ROCKIES.
EXPECTING A SLIGHT E/W GRADIENT IN TEMPERATURES TOMORROW WITH THE
EAST REMAINING UNDER THE INFLUENCE OF THE SFC HIGH LONGER INTO THE
DAY...FORECAST HIGHS RANGE FROM THE MID/UPPER 70S IN THE EAST TO
LOWER 80S IN THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY. CHANCES OF PRECIPITATION
WILL BE A BIT OF A TOUGH CALL FROM WEDNESDAY THROUGH SUNDAY.
WE WILL KICK OFF MONDAY NIGHT WITH A SHORTWAVE UPPER LEVEL RIDGE
CONTINUING TO MOVE EAST INTO THE HIGH PLAINS. THIS WILL KEEP
CONDITIONS DRY. AT THE SAME TIME...A BROAD LONGWAVE TROUGH MAKES
ITS WAY INTO THE PACIFIC NORTHWEST.
TUESDAY IS SHAPING UP TO BE THE WARMEST DAY OF THE LONG TERM
FORECAST WITH A SURFACE TROUGH IN THE LEE OF THE ROCKY MOUNTAINS
INCREASING IN INTENSITY. WIND SPEEDS WILL ALSO INCREASE DUE TO THE
TIGHTENING OF THE SURFACE PRESSURE GRADIENT. ALTHOUGH TUESDAY
SHOULD BE WINDY...MODEL SOLUTIONS ARE BACKING OFF OF WIND SPEEDS
A BIT COMPARED TO SOLUTIONS FROM YESTERDAY AND THIS DOES NOT
APPEAR TO BE THE SOLID WIND ADVISORY THAT IT LOOKED LIKE
YESTERDAY. WIND SPEEDS STILL LOOK LIKE THEY WILL BE STRONGER IN
THE WESTERN CWA. 850 MB TEMPERATURES INDICATE HOTTER
WEATHER...INTO THE UPPER 80S AND LOWER 90S...BEING A BIT WARMER TO
THE WEST. WE COULD GET A WARM FRONT TO POKE INTO THE WESTERN CWA
BY TUESDAY AFTERNOON BUT CAPPING SHOULD BE STRONG....SO I AM NOT
ANTICIPATING ANY CONVECTION BREAKING OUT TUESDAY AFTERNOON DESPITE
THE POTENTIAL FOCUS OF THE WARM FRONT. THE INFLUENCE OF THE RIDGE
WILL GIVE US ONE MORE DRY NIGHT BEFORE A SHIFT OCCURS IN THE
PATTERN.
BY WEDNESDAY...THE AFOREMENTIONED LONGWAVE TROUGH SETTLES INTO THE
NORTHWESTERN UNITED STATES AND PUSHES AN ASSOCIATED COLD FRONT
SOUTHEAST THROUGH MUCH OF THE CWA BY WEDNESDAY AFTERNOON. MODELS
ARE TRENDING FASTER WITH THIS PUSH...WITH THE COLD FRONT
PROBABLY STILL DRAPED ACROSS THE SOUTHEASTERN CWA BY TUESDAY
AFTERNOON. WE SHOULD BE CAPPED ENOUGH TO PREVENT CONVECTION FROM
DEVELOPING WEDNESDAY AFTERNOON. THE FRONT HAS BEEN LONG ADVERTISED
TO STALL BY WEDNESDAY EVENING...BUT AGAIN...THIS WILL BE FARTHER
SOUTH THAN PREVIOUS RUNS OF MODELS. AS A LOW-LEVEL JET
DEVELOPS...THIS WILL ENCOURAGE NOCTURNAL CONVECTION...WHICH COULD
BE STRONG TO SEVERE GIVEN THE EXPECTED SEVERE PARAMETERS. IN
FACT...THE SCENARIO OF DRY WEATHER DURING THE DAY WHEN WE ARE
CAPPED AND THEN A SHOT AT NOCTURNAL ELEVATED CONVECTION WHEN THE
CAP BREAKS DOWN WILL BE THE PREDICTED WEATHER FOR MOST OF THE REST
OF THE LONG TERM FORECAST AS THE BOUNDARY HANGS AROUND AND
EVENTUALLY MOVES NORTH. FOR NOW IT APPEARS THAT RAIN/THUNDERSTORM
CHANCES WILL BE GENERALLY MORE TO THE NORTH WHERE THE BETTER LOW-
LEVEL NIGHT TIME CONVERGENCE WILL BE. ALSO...THESE NOCTURNAL
STORMS CAN ONCE AGAIN BE STRONG TO SEVERE EACH NIGHT.
&&
.AVIATION...18Z TAF. QUIET WEATHER EXPECTED FOR THIS TAF
PERIOD...AND OUTSIDE OF THE POSSIBILITY FOR AN OCCASIONAL HIGH END
MVFR CEILING FOR A COUPLE HOURS EARLY THIS AFTERNOON...VFR
CONDITIONS WILL REIGN. SURFACE HIGH PRESSURE CURRENTLY CENTERED
OVER WRN NEB...WHICH WILL KEEP WINDS GENERALLY NORTHERLY THROUGH
THE AFTERNOON...WITH DIMINISHING SPEEDS. THROUGH THE
EVENING/OVERNIGHT HOURS AND INTO TOMORROW...WINDS WILL REMAIN
FAIRLY LIGHT...AND GRADUALLY BECOME MORE EASTERLY...THEN
SOUTHEASTERLY AS THE SURFACE HIGH SLIDES OFF TO THE EAST OF THE
CWA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/SHORT...ADO
LONG...HEINLEIN
000
FXUS63 KLBF 202046 CCB
AFDLBF
AREA FORECAST DISCUSSION...CORRECTED TYPO
NATIONAL WEATHER SERVICE NORTH PLATTE NE
332 PM CDT SUN MAY 20 2012
.DISCUSSION...
A WEAK UPPER LEVEL DISTURBANCE ACROSS ERN WY AND RETURN MOISTURE UP
THE HIGH PLAINS MAY BE SUFFICIENT TO CARRY ISOLATED TSTMS EAST AND
SOUTHEAST THROUGH SWRN NEB THIS EVENING. THE NAM AND GFS SUGGEST
ANOTHER WEAK AREA OF CONVECTION DEVELOPING ACROSS NCNTL NEB LATER
TONIGHT AS THE LOW LEVEL JET STRENGTHENS. SEVERE WEATHER CONCERNS
REVOLVE AROUND LARGE HAIL BUT SHEAR PROFILES WHICH ARE QUITE STRONG
SUGGEST THE UPDRAFTS ACROSS SERN WY THIS AFTN ARE BEING RIPPED
APART. THUS UPDRAFT STRENGTH MAY BE INSUFFICIENT TO MAINTAIN STORM
DEVELOPMENT.
ON MONDAY...MOISTURE AND SOUTH WINDS INCREASE TO 20 TO 30 MPH. THE
CONSENSUS IS FOR LOW PRESSURE TO DEEPEN ACROSS SERN MT WITH A WARM
FRONTAL ARM EXTENDING SOUTHEAST THROUGH NCNTL NEB. NAM12 K INDICES
INCREASE TO NEAR 40C. THE ENSUING DRYLINE BULGE AND MOIST TONGUE
MONDAY AFTERNOON MAY SPARK ISOLATED STRONG OR SEVERE THUNDERSTORMS.
SINCE IT IS THE LATE MAY THERES REALLY NO SENSE DISCRIMINATING
BETWEEN SEVERE AND NON SEVERE STORMS. ANYTHING THAT FORMS COULD
BECOME SEVERE. THIS ACTIVITY SHOULD DIMINISH AROUND SUNSET AND THE
DRYLINE SHOULD RETREAT WEST OF HIGHWAY 61.
VERY WARM WEATHER IS EXPECTED TUESDAY. THE DRYLINE WILL SURGE
FARTHER EAST TOWARD KVTN AND NORTHWEST NEB WILL TORCH OUT IN THE
MID 90S. THE ECM REALLY SHARPENS THE DRYLINE AND ALTHOUGH 700MB
TEMPS WILL RISE TOWARD 12C A SMALL AREA OF NRN CHERRY COUNTY MIGHT
SEE AN ISOLATED TSTM. A FAIRLY DEEP SOUTHERLY FLOW DEVELOPS BELOW
800 MB WHICH SHOULD HOLD TEMPS IN THE 80S ALONG AND EAST OF
HIGHWAY 183. WEST OF 183...SKIES THE LIMIT LITERALLY AS MIXING
HEIGHTS WILL DETERMINE MAX TEMPS. HIGHS IN THE LOW TO MID 90S LOOK
REASONABLE. MEANWHILE LOW PRESSURE WILL DEEPEN TO AROUND 990 MB
ACROSS CNTL SD AND SOUTH WINDS SHOULD INCREASE TO AROUND 30 MPH
ALONG AND EAST OF HIGHWAY 83.
A COLD FRONT WILL DROP THROUGH TUESDAY NIGHT. ALL MODELS INDICATE
A 700MB THERMAL RIDGE WILL SEND 700MB TEMPS TO 14-15C AND CAP TSTM
DEVELOPMENT ALL AREAS EXCEPT PERHAPS THE FAR NORTHEAST.
LOW PRESSURE WILL SETTLE ACROSS SERN COLO WEDNESDAY AFTERNOON WITH
THETA E ADVECTION NORTH OF THE FRONT ACROSS WRN/NCNTL NEB. ALL
MODELS INDICATE STRONG WINDS ALOFT SUFFICIENT FOR SEVERE STORM
DEVELOPMENT. THE CONSENSUS IS FOR STORMS TO FIRE ACROSS NORTHWEST
NEB LATE IN THE DAY WHICH SHOULD DEVELOP EAST AND SOUTHEAST AS AN
ORGANIZED MCS. SFC LOW PRESSURE ACROSS ERN COLO WILL TRACK EAST
ALONG OR NEAR THE NEB-KS BORDER OVERNIGHT.
THURSDAY THROUGH SUNDAY...
MODELS STILL AGREE THAT A LARGE TROUGH WILL BECOME ESTABLISHED
ACROSS THE WESTERN CONUS...WHILE A SPRAWLING UPPER LEVEL HIGH
PRESSURE SYSTEM DEVELOPS ACROSS THE EASTERN CONUS. THIS PUTS OUR
AREA SOMEWHERE IN THE MIDDLE. THE TREND TODAY IN BOTH THE
OPERATIONAL AND ENSEMBLE SOLUTIONS...IS TO KEEP THE UPPER LEVEL HIGH
A LITTLE FARTHER EAST ACROSS THE TENNESSEE VALLEY REGION...AND
DEVELOP THE WEST COAST TROUGH FARTHER EAST. THE SLIGHT SHIFT
EASTWARD SHIFT OF THESE FEATURES WOULD ALLOW FOR SOMEWHAT BETTER
GULF MOISTURE RETURN INTO THE PLAINS. ALSO...MID LEVEL TEMPERATURES
WOULD BE SLIGHTLY COOLER...AND MEAN BETTER CHANCES FOR T-STORMS.
WHILE HIGH TEMPERATURES STILL APPEAR THEY WILL BE VERY WARM DURING
THE WEEKEND...WE MAY NOT SEE HOT TEMPERATURES LIKE SOME OF THE
OPERATIONAL MODELS WHERE HINTING AT YESTERDAY.
FOR NOW...THE BEST APPROACH TO THE FORECAST IS TO GRADUALLY RAISE
HIGHS FROM THE UPPER 70S THURSDAY...TO THE MID AND UPPER 80S
SATURDAY AND SUNDAY. AT THIS TIME WILL CONTINUE SOME LOW CHANCE AND
SLIGHT CHANCE POPS DUE TO AMPLE INSTABILITY...AND THE TREND TOWARD A
LITTLE COOLER MID LEVEL TEMPS.
&&
.AVIATION...
MAINLY CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HRS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. AS HIGH PRESSURE
DOMINATES. AS THE HIGH DRIFTS EAST TONIGHT...SOUTH TO SOUTHEAST
WINDS OF 5 TO 10 KTS CAN BE EXPECTED ON THE BACKSIDE OF THE
HIGH...INCREASING TO 10 TO 20 KTS DURING THE DAY MONDAY.
&&
.FIRE WEATHER...
VERY DRY AIR WILL SPREAD INTO THE NEBRASKA PANHANDLE MONDAY AND
TUESDAY IN RESPONSE TO DEEPENING LOW PRESSURE ACROSS THE NRN
PLAINS. WIND GUSTS IN EXCESS OF 30 MPH ARE LIKELY ACROSS THE ERN
PANHANDLE AND WRN NEB. IF THE DRYLINE SHARPENS UP AS FCST BY SOME
MODELS...CRITICAL FIRE DANGER MAY DEVELOP. THIS IS MOSTLY LIKELY
TUESDAY AFTN AND THE DRYLINE BEHAVIOR MONDAY WILL PROVIDE A
BASELINE FOR TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CDC
AVIATION/EXTENDED...TAYLOR
000
FXUS63 KLBF 202044 CCA
AFDLBF
AREA FORECAST DISCUSSION...CORRECTED TO ADD WEDS DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
332 PM CDT SUN MAY 20 2012
.DISCUSSION...
A WEAK UPPER LEVEL DISTURBANCE ACROSS ERN WY AND RETURN MOISTURE UP
THE HIGH PLAINS MAY BE SUFFICIENT TO CARRY ISOLATED TSTMS EAST AND
SOUTHEAST THROUGH SWRN NEB THIS EVENING. THE NAM AND GFS SUGGEST
ANOTHER WEAK AREA OF CONVECTION DEVELOPING ACROSS NCNTL NEB LATER
TONIGHT AS THE LOW LEVEL JET STRENGTHENS. SEVERE WEATHER CONCERNS
REVOLVE AROUND LARGE HAIL BUT SHEAR PROFILES WHICH ARE QUITE STRONG
SUGGEST THE UPDRAFTS ACROSS SERN WY THIS AFTN ARE BEING RIPPED
APART. THUS UPDRAFT STRENGTH MAY BE INSUFFICIENT TO MAINTAIN STORM
DEVELOPMENT.
ON MONDAY...MOISTURE AND SOUTH WINDS INCREASE TO 20 TO 30 MPH. THE
CONSENSUS IS FOR LOW PRESSURE TO DEEPEN ACROSS SERN MT WITH A WARM
FRONTAL ARM EXTENDING SOUTHEAST THROUGH NCNTL NEB. NAM12 K INDICES
INCREASE TO NEAR 40C. THE ENSUING DRYLINE BULGE AND MOIST TONGUE
MONDAY AFTERNOON MAY SPARK ISOLATED STRONG OR SEVERE THUNDERSTORMS.
SINCE IT IS THE LATE MAY THERES REALLY NO SENSE DISCRIMINATING
BETWEEN SEVERE AND NON SEVERE STORMS. ANYTHING THAT FORMS COULD
BECOME SEVERE. THIS ACTIVITY SHOULD DIMINISH AROUND SUNSET AND THE
DRYLINE SHOULD RETREAT WEST OF HIGHWAY 61.
VERY WARM WEATHER IS EXPECTED TUESDAY. THE DRYLINE WILL SURGE
FARTHER EAST TOWARD KVTN AND NORTHWEST NEB WILL TORCH OUT IN THE
MID 90S. THE ECM REALLY SHARPENS THE DRYLINE AND ALTHOUGH 700MB
TEMPS WILL RISE TOWARD 12C A SMALL AREA OF NRN CHERRY COUNTY MIGHT
SEE AN ISOLATED TSTM. A FAIRLY DEEP SOUTHERLY FLOW DEVELOPS BELOW
800 MB WHICH SHOULD HOLD TEMPS IN THE 80S ALONG AND EAST OF
HIGHWAY 183. WEST OF 183...SKIES THE LIMIT LITERALLY AS MIXING
HEIGHTS WILL DETERMINE MAX TEMPS. HIGHS IN THE LOW TO MID 90S LOOK
REASONABLE. MEANWHILE LOW PRESSURE WILL DEEPEN TO AROUND 990 MB
ACROSS CNTL SD AND SOUTH WINDS SHOULD INCREASE TO AROUND 30 MPH
ALONG AND EAST OF HIGHWAY 83.
A COLD FRONT WILL DROP THROUGH TUESDAY NIGHT. ALL MODELS INDICATE
A 700MB THERMAL RIDGE WILL SEND 700MB TEMPS TO 14-15C AND CAP TSTM
DEVELOPMENT ALL AREAS EXCEPT PERHAPS THE FAR NORTHEAST.
LOW PRESSURE WILL SETTLE ACROSS SERN COLO WEDNESDAY AFTERNOON WITH
THETA E ADVECTION NORTH OF THE FRONT ACROSS WRN/NCNTL NEB. ALL
MODELS INDICATE STRONG WINDS ALOFT SUFFICIENT FOR SEVERE STORM
DEVELOPMENT. THE CONSENSUS IS FOR STORMS TO FIRE ACROSS NORTHWEST
NEB LATE IN THE DAY WHICH SHOULD DEVELOP EAST AND SOUTHEAST AS AN
ORGANIZED MCS. SFC LOW PRESSURE ACROSS ERN COLO WILL TRACK EAST
ALONG OR NEAR THE NEB-KS BORDER OVERNIGHT.
THURSDAY THROUGH SUNDAY...
MODELS STILL AGREE THAT A LARGE TROUGH WILL BECOME ESTABLISHED
ACROSS THE WESTERN CONUS...WHILE A SPRAWLING UPPER LEVEL HIGH
PRESSURE SYSTEM DEVELOPS ACROSS THE EASTERN CONUS. THIS PUTS OUR
AREA IN THE SOMEWHERE IN THE MIDDLE. THE TREND TODAY IN BOTH THE
OPERATIONAL AND ENSEMBLE SOLUTIONS...IS TO KEEP THE UPPER LEVEL HIGH
A LITTLE FARTHER EAST ACROSS THE TENNESSEE VALLEY REGION...AND
DEVELOP THE WEST COAST TROUGH FARTHER EAST. THE SLIGHT SHIFT
EASTWARD SHIFT OF THESE FEATURES WOULD ALLOW FOR SOMEWHAT BETTER
GULF MOISTURE RETURN INTO THE PLAINS. ALSO...MID LEVEL TEMPERATURES
WOULD BE SLIGHTLY COOLER...AND MEAN BETTER CHANCES FOR T-STORMS.
WHILE HIGH TEMPERATURES STILL APPEAR THEY WILL BE VERY WARM DURING
THE WEEKEND...WE MAY NOT SEE HOT TEMPERATURES LIKE SOME OF THE
OPERATIONAL MODELS WHERE HINTING AT YESTERDAY.
FOR NOW...THE BEST APPROACH TO THE FORECAST IS TO GRADUALLY RAISE
HIGHS FROM THE UPPER 70S THURSDAY...TO THE MID AND UPPER 80S
SATURDAY AND SUNDAY. AT THIS TIME WILL CONTINUE SOME LOW CHANCE AND
SLIGHT CHANCE POPS DUE TO AMPLE INSTABILITY...AND THE TREND TOWARD A
LITTLE COOLER MID LEVEL TEMPS.
&&
.AVIATION...
MAINLY CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HRS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. AS HIGH PRESSURE
DOMINATES. AS THE HIGH DRIFTS EAST TONIGHT...SOUTH TO SOUTHEAST
WINDS OF 5 TO 10 KTS CAN BE EXPECTED ON THE BACKSIDE OF THE
HIGH...INCREASING TO 10 TO 20 KTS DURING THE DAY MONDAY.
&&
.FIRE WEATHER...
VERY DRY AIR WILL SPREAD INTO THE NEBRASKA PANHANDLE MONDAY AND
TUESDAY IN RESPONSE TO DEEPENING LOW PRESSURE ACROSS THE NRN
PLAINS. WIND GUSTS IN EXCESS OF 30 MPH ARE LIKELY ACROSS THE ERN
PANHANDLE AND WRN NEB. IF THE DRYLINE SHARPENS UP AS FCST BY SOME
MODELS...CRITICAL FIRE DANGER MAY DEVELOP. THIS IS MOSTLY LIKELY
TUESDAY AFTN AND THE DRYLINE BEHAVIOR MONDAY WILL PROVIDE A
BASELINE FOR TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CDC
AVIATION/EXTENDED...TAYLOR
000
FXUS63 KLBF 202032
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
332 PM CDT SUN MAY 20 2012
.DISCUSSION...
A WEAK UPPER LEVEL DISTURBANCE ACROSS ERN WY AND RETURN MOISTURE UP
THE HIGH PLAINS MAY BE SUFFICIENT TO CARRY ISOLATED TSTMS EAST AND SOUTHEAST
THROUGH SWRN NEB THIS EVENING. THE NAM AND GFS SUGGEST ANOTHER
WEAK AREA OF CONVECTION DEVELOPING ACROSS NCNTL NEB LATER TONIGHT
AS THE LOW LEVEL JET STRENGTHENS. SEVERE WEATHER CONCERNS REVOLVE
AROUND LARGE HAIL BUT SHEAR PROFILES WHICH ARE QUITE STRONG
SUGGEST THE UPDRAFTS ACROSS SERN WY THIS AFTN ARE BEING RIPPED
APART. THUS UPDRAFT STRENGTH MAY BE INSUFFICIENT TO MAINTAIN STORM
DEVELOPMENT.
ON MONDAY...MOISTURE AND SOUTH WINDS INCREASE TO 20 TO 30 MPH. THE
CONSENSUS IS FOR LOW PRESSURE TO DEEPEN ACROSS SERN MT WITH A WARM
FRONTAL ARM EXTENDING SOUTHEAST THROUGH NCNTL NEB. NAM12 K INDICES
INCREASE TO NEAR 40C. THE ENSUING DRYLINE BULGE AND MOIST TONGUE MONDAY
AFTERNOON MAY SPARK ISOLATED STRONG OR SEVERE THUNDERSTORMS. SINCE
IT IS THE LATE MAY THERES REALLY NO SENSE DISCRIMINATING BETWEEN
SEVERE AND NON SEVERE STORMS. ANYTHING THAT FORMS COULD BECOME
SEVERE. THIS ACTIVITY SHOULD DIMINISH AROUND SUNSET AND THE
DRYLINE SHOULD RETREAT WEST OF HIGHWAY 61.
VERY WARM WEATHER IS EXPECTED TUESDAY. THE DRYLINE WILL SURGE
FARTHER EAST TOWARD KVTN AND NORTHWEST NEB WILL TORCH OUT IN THE
MID 90S. THE ECM REALLY SHARPENS THE DRYLINE AND ALTHOUGH 700MB
TEMPS WILL RISE TOWARD 12C A SMALL AREA OF NRN CHERRY COUNTY MIGHT
SEE AN ISOLATED TSTM. A FAIRLY DEEP SOUTHERLY FLOW DEVELOPS BELOW
800 MB WHICH SHOULD HOLD TEMPS IN THE 80S ALONG AND EAST OF
HIGHWAY 183. WEST OF 183...SKIES THE LIMIT LITERALLY AS MIXING
HEIGHTS WILL DETERMINE MAX TEMPS. HIGHS IN THE LOW TO MID 90S LOOK
REASONABLE. MEANWHILE LOW PRESSURE WILL DEEPEN TO AROUND 990 MB
ACROSS CNTL SD AND SOUTH WINDS SHOULD INCREASE TO AROUND 30 MPH
ALONG AND EAST OF HIGHWAY 83.
A COLD FRONT WILL DROP THROUGH TUESDAY NIGHT. ALL MODELS INDICATE
A 700MB THERMAL RIDGE WILL SEND 700MB TEMPS TO 14-15C AND CAP TSTM
DEVELOPMENT ALL AREAS EXCEPT PERHAPS THE FAR NORTHEAST.
THURSDAY THROUGH SUNDAY...
MODELS STILL AGREE THAT A LARGE TROUGH WILL BECOME ESTABLISHED
ACROSS THE WESTERN CONUS...WHILE A SPRAWLING UPPER LEVEL HIGH
PRESSURE SYSTEM DEVELOPS ACROSS THE EASTERN CONUS. THIS PUTS OUR
AREA IN THE SOMEWHERE IN THE MIDDLE. THE TREND TODAY IN BOTH THE
OPERATIONAL AND ENSEMBLE SOLUTIONS...IS TO KEEP THE UPPER LEVEL HIGH
A LITTLE FARTHER EAST ACROSS THE TENNESSEE VALLEY REGION...AND
DEVELOP THE WEST COAST TROUGH FARTHER EAST. THE SLIGHT SHIFT
EASTWARD SHIFT OF THESE FEATURES WOULD ALLOW FOR SOMEWHAT BETTER
GULF MOISTURE RETURN INTO THE PLAINS. ALSO...MID LEVEL TEMPERATURES
WOULD BE SLIGHTLY COOLER...AND MEAN BETTER CHANCES FOR T-STORMS.
WHILE HIGH TEMPERATURES STILL APPEAR THEY WILL BE VERY WARM DURING
THE WEEKEND...WE MAY NOT SEE HOT TEMPERATURES LIKE SOME OF THE
OPERATIONAL MODELS WHERE HINTING AT YESTERDAY.
FOR NOW...THE BEST APPROACH TO THE FORECAST IS TO GRADUALLY RAISE
HIGHS FROM THE UPPER 70S THURSDAY...TO THE MID AND UPPER 80S
SATURDAY AND SUNDAY. AT THIS TIME WILL CONTINUE SOME LOW CHANCE AND
SLIGHT CHANCE POPS DUE TO AMPLE INSTABILITY...AND THE TREND TOWARD A
LITTLE COOLER MID LEVEL TEMPS.
&&
.AVIATION...
MAINLY CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HRS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. AS HIGH PRESSURE
DOMINATES. AS THE HIGH DRIFTS EAST TONIGHT...SOUTH TO SOUTHEAST
WINDS OF 5 TO 10 KTS CAN BE EXPECTED ON THE BACKSIDE OF THE
HIGH...INCREASING TO 10 TO 20 KTS DURING THE DAY MONDAY.
&&
.FIRE WEATHER...
VERY DRY AIR WILL SPREAD INTO THE NEBRASKA PANHANDLE MONDAY AND
TUESDAY IN RESPONSE TO DEEPENING LOW PRESSURE ACROSS THE NRN
PLAINS. WIND GUSTS IN EXCESS OF 30 MPH ARE LIKELY ACROSS THE ERN
PANHANDLE AND WRN NEB. IF THE DRYLINE SHARPENS UP AS FCST BY SOME
MODELS...CRITICAL FIRE DANGER MAY DEVELOP. THIS IS MOSTLY LIKELY
TUESDAY AFTN AND THE DRYLINE BEHAVIOR MONDAY WILL PROVIDE A
BASELINE FOR TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CDC
AVIATION/EXTENDED...TAYLOR
000
FXUS63 KOAX 202025
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
325 PM CDT SUN MAY 20 2012
.DISCUSSION...
HIGH PRESSURE WAS LOCATED OVER THE REGION AT 19Z WITH COLD FRONT
PUSHING SOUTHEAST INTO THE MID MISSISSIPPI VALLEY. THIS AREA OF
HIGH PRESSURE WILL SLIDE SLOWLY EAST TONIGHT THROUGH MONDAY NIGHT
AS LOW PRESSURE DEVELOPS OVER THE MONTANA HIGH PLAINS. ON TUESDAY
THE LOW BEGINS TO MOVE EAST PULLING A COLD FRONT INTO THE WESTERN
HIGH PLAINS AND MUCH WARMER TEMPERATURES INTO THE CENTRAL PLAINS.
THE COLD FRONT THEN MOVES INTO THE CENTRAL PLAINS TUESDAY NIGHT
AND WEDNESDAY WITH SOME CHANCE OF THUNDERSTORMS BUT LOOKS FOR NOW
LIKE BETTER MOISTURE AND DYNAMICS WILL BE TO THE NORTH OF THE
AREA.
THIS FRONTAL BOUNDARY WILL CONTINUE TO BE A FACTOR IN THE EXTENDED
PERIOD AS IT STALLS ACROSS NORTHEAST KANSAS AND NORTHERN MISSOURI
WITH A CONTINUED CHANCE OF STORMS ALONG AND NORTH OF THE BOUNDARY
THURSDAY THROUGH FRIDAY. AFTER THIS THE GFS AND EURO CONTINUE TO
SHOW DIFFERENT SOLUTIONS IN TIMING ON MOVING THE FRONT NORTH AS
UPPER RIDGE BUILDS INTO THE UPPER MISSISSIPPI VALLEY. PRETTY MUCH
SPLIT THE DIFFERENCE FOR NOW DURING THE LATER PART OF THE EXTENDED
DUE TO THE UNCERTAINTY BETWEEN THE MODELS. MAY HAVE TO BOOST HIGH
TEMPERATURES DURING THIS TIME IN LATER FORECASTS IF EURO TURNS OUT
TO BE CORRECT WITH ITS STRONG RIDGING.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE CENTRAL PLAINS OF
NEBRASKA AND WEST IOWA. LINGERING MVFR CIGS ACROSS SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA WILL CONTINUE TO THIN AND LIFT AND
BECOME MOSTLY VFR AFTER 22Z. GUSTY NORTH WINDS...14G24KT WILL
CONTINUE AT ALL THREE TAF SITES UNTIL AROUND 01Z WHEN THEY WILL
DIMINISH...BECOME LIGHT AND VARIABLE...THEN BECOME SOUTH AROUND
10KT AFTER 13Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/MEYER
000
FXUS63 KGID 201744
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1244 PM CDT SUN MAY 20 2012
.AVIATION...18Z TAF. QUIET WEATHER EXPECTED FOR THIS TAF
PERIOD...AND OUTSIDE OF THE POSSIBILITY FOR AN OCCASIONAL HIGH END
MVFR CEILING FOR A COUPLE HOURS EARLY THIS AFTERNOON...VFR
CONDITIONS WILL REIGN. SURFACE HIGH PRESSURE CURRENTLY CENTERED
OVER WRN NEB...WHICH WILL KEEP WINDS GENERALLY NORTHERLY THROUGH
THE AFTERNOON...WITH DIMINISHING SPEEDS. THROUGH THE
EVENING/OVERNIGHT HOURS AND INTO TOMORROW...WINDS WILL REMAIN
FAIRLY LIGHT...AND GRADUALLY BECOME MORE EASTERLY...THEN
SOUTHEASTERLY AS THE SURFACE HIGH SLIDES OFF TO THE EAST OF THE
CWA.
&&
PREV DISCUSSION... /ISSUED 440 AM CDT SUN MAY 20 2012/
SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
SHORT...PFANNKUCH
LONG...BRYANT
000
FXUS63 KLBF 201744
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1244 PM CDT SUN MAY 20 2012
.AVIATION...MAINLY CLEAR SKIES ARE EXPECTED FOR THE NEXT 24 HRS
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...AS HIGH PRESSURE
DOMINATES. WITH THE CENTER OF THE HIGH IN THE AREA THIS
AFTERNOON...SFC WINDS WILL BE VARIABLE AT 5 TO 10 KTS. THEN...AS
THE HIGH DRIFTS EAST TONIGHT...SOUTH TO SOUTHEAST WINDS OF 5 TO 10
KTS CAN BE EXPECTED ON THE BACKSIDE OF THE HIGH.
&&
.PREV DISCUSSION... /ISSUED 403 AM CDT SUN MAY 20 2012/
DISCUSSION...
STRONG UPPER LEVEL LOW CONTINUES TO MOVE ACROSS THE PLAINS...WITH
SOME LINGER CLOUDS OVER CENTRAL/EASTERN NEB STILL THIS
MORNING...HOWEVER SHOWERS HAVE PUSHED EAST OF THE CWA. AT THE
SURFACE HIGH PRESSURE IS BUILDING SOUTH ALONG THE FRONT RANGE OF
THE ROCKIES. LATEST HOURLY OBS SHOW TEMPS HAVE FALLEN INTO THE
40S WITH CLEAR SKIES IN THE WEST...WHILE HOLDING ONTO LOW 50S
BENEATH THE CLOUDS.
SYSTEM WILL CONTINUE TO PUSH EAST WHILE THE SURF HIGH BUILDS
ACROSS THE AREA. WINDS WILL BE LIGHT AND VARIABLE MOST OF THE
DAY...AND SWITCH TO THE SOUTH AS THE HIGH SHIFTS SOUTH OF THE ARE
AREA LATER TODAY. SEASONAL TEMPS EXPECTED FOR THE DAY...HIGHS
AROUND 70.
THIS AFTERNOON STEEP LAPSE RATE AND SOME MARGINAL INSTABILITY
/CAPE AROUND 500+ J/KG WITH LI/S CLOSE TO NEGATIVE ONE/ DEVELOP
OVER THE HIGHER TERRAIN OF THE FRONT RANGE. ISOLD TO SCT STORMS
EXPECTED WITH THE PEAK HEAT...THEN STORMS WILL MOVE EASTERLY WITH
ZONAL TO NW FLOW. ENERGY REMAINS OVER THE HIGHER TERRAIN WITH
SUBSIDENCE FROM THE HIGH. THIS SHOULD CAUSE THE STORMS TO DIE OFF
AS THE PUSH EAST...AND WILL GO DRY FOR THE CWA.
SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA MONDAY AND MONDAY
NIGHT. MODELS IN GOOD AGREEMENT WITH A NARROW BAND OF INSTABILITY
TO DEVELOP OVER THE CENTRAL PART OF THE CWA. CAP SHOULD BE WEAKEN
BY MID TO LATE AFTERNOON...HOWEVER MOISTURE IS QUESTIONABLE.
EXPECT A BROKEN LINE...MAYBE MORE ISOLATED STORMS...TO DEVELOP ON
THE TROUGH AS IT WORKS EAST DURING THE AFTERNOON. BETTER ENERGY IS
LOCATED ACROSS THE NORTHERN HALF OF THE CWA...WHICH WORKS EAST
INTO THE EVENING PERIOD.
ANOTHER WEAK SYSTEM WILL MOVE ACROSS THE AREA FOR WEDNESDAY. AGAIN
WILL NEED LOW POPS. SYSTEM IS SLOWER AND WILL CONTINUE POPS INTO
THURSDAY. STILL WARM TEMPS AS GUIDANCE IN THE 70S TO LOW 80S.
BY THE WEEKEND A RIDGE BUILDS ACROSS THE SOUTHEAST CONUS...WITH A
TROUGH DIGGING IN THE WEST. ECMWF HAS ALIGNED CLOSER TO THE GFS
AND ENSEMBLE MEAN WITH PLACEMENT OF THE RIDGE. NEBRASKA WILL BE IN
A TRANSITION ZONE...WITH HIGHS IN THE 90S...POSSIBLY MID OR
UPPER...TO THE SOUTHEAST...AND CLOSER TO 80 TO THE NORTHWEST. WILL
CONTINUE TO MONITOR AND HAVE BLENDED FORECAST. ALSO WITH THE
BOUNDARY IN THE AREA...WILL SEE THE CHANCE FOR THUNDERSTORMS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...99
AVIATION...TAYLOR
000
FXUS63 KOAX 201741
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1241 PM CDT SUN MAY 20 2012
.UPDATE...
.AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK.
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE CENTRAL PLAINS OF
NEBRASKA AND WEST IOWA. LINGERING MVFR CIGS ACROSS SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA WILL CONTINUE TO THIN AND LIFT AND
BECOME MOSTLY VFR AFTER 22Z. GUSTY NORTH WINDS...14G24KT WILL
CONTINUE AT ALL THREE TAF SITES UNTIL AROUND 01Z WHEN THEY WILL
DIMINISH...BECOME LIGHT AND VARIABLE...THEN BECOME SOUTH AROUND
10KT AFTER 13Z.
&&
.PREV DISCUSSION... /ISSUED 300 AM CDT SUN MAY 20 2012/
SHORTWAVE TROUGH THAT HELPED BRING THUNDERSTORMS TO THE AREA
SATURDAY CONTINUED TO LIFT NORTHEAST. HEIGHT FALLS ASSOCIATED WITH
THIS FEATURE WERE PRETTY WEAK...BUT DID HELP PUSH A COLD FRONT
THROUGH THE AREA. NORTH OR NORTHWEST WINDS TODAY WILL BRING IN
COOLER AIR COMPARED TO YESTERDAY...WITH HIGHS TODAY EXPECTED TO BE
IN THE 70S. A RIDGE OF HIGH PRESSURE AT THE SURFACE BUILDS OVER
THE AREA THIS AFTERNOON AND EVENING. THIS SHOULD ALLOW FOR DECENT
RADIATIONAL COOLING WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. LOWS
ARE EXPECTED TO DROP INTO THE 40S.
SOUTHERLY FLOW INCREASES ON MONDAY AND SHOULD HELP BRING LOW LEVEL
MOISTURE BACK INTO CENTRAL AND WESTERN NEBRASKA. 00Z GFS RUN THEN
BRINGS 850 MB DEWPOINTS OF 6-12 DEGREES CELSIUS INTO NORTHEAST
NEBRASKA MONDAY NIGHT. FELT THAT THE GFS HAD A DECENT HANDLE ON THE
SITUATION AND IT DID DEVELOP SOME PRECIPITATION. AT THIS POINT...DID
NOT FAVOR THE 00Z NAM SOLUTION WHICH DEVELOPED PRECIPITATION INTO
SOUTHWEST IOWA AND PARTS OF SOUTHEAST NEBRASKA AFTER MIDNIGHT MONDAY
NIGHT. A COLD FRONT WILL BE PUSHING EASTWARD ACROSS THE NORTHERN
PLAINS TUESDAY NIGHT AND COULD HELP TRIGGER SHOWERS OR THUNDERSTORMS
FOR PARTS OF NORTHEAST NEBRASKA AFTER MIDNIGHT. FELT THINGS LOOKED
BETTER FARTHER NORTH...SO DID NOT MENTION ANY SHOWERS TUESDAY
NIGHT. THIS WILL NEED TO BE MONITORED FOR FUTURE UPDATES.
THE PATTERN MID WEEK SHOULD FEATURE A TROUGH OVER THE ROCKIES WHICH
WILL PARTIALLY LIFT OUT INTO THE NORTHERN PLAINS THURSDAY. AT THE
SAME TIME...A DEEPER TROUGH/CLOSED LOW WILL BE DIGGING ALONG THE
WEST COAST. ALTHOUGH THE MODELS AGREE ON THE GENERAL PATTERN...THE
12Z ECMWF SHOWED A 500 MB RIDGE CENTERED OVER MISSOURI...WHILE THE
00Z GFS HAD THE HIGH FARTHER SOUTHEAST. TELECONNECTIONS TENDED TO
SUPPORT THE GFS SOLUTION...WHICH ALSO HAD SOME SUPPORT FROM THE
CANADIAN GEM. NOT SURPRISINGLY...THE 00Z ECMWF SOLUTION TRENDED
MORE TOWARD THE GFS. GENERALLY USED A BLEND OF 00Z GFS AND 00Z
ECMWF FOR DAYS 4 TO 7.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KLBF 201132
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
632 AM CDT SUN MAY 20 2012
.AVIATION...
FOR THE KVTN AND KLBF TERMINALS THROUGH 12Z MONDAY.
THE UPPER LEVEL TROUGH OF LOW PRESSURE...RESPONSIBLE FOR
PRECIPITATION SATURDAY NIGHT...WILL TRACK INTO THE UPPER MISSISSIPPI
VALLEY TODAY. THIS WILL LEAD TO MOSTLY CLEAR SKIES ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA WITH SOME SCATTERED HIGH LEVEL CLOUDINESS AON
25000 FT AGL. DECAYING THUNDERSTORMS OVER EASTERN WYOMING AND THE
WESTERN NEBRASKA PANHANDLE...MAY RESULT IN SOME SCATTERED HIGH LEVEL
CLOUDINESS OVER THE EASTERN NEBRASKA PANHANDLE AND WESTERN NEBRASKA
THIS EVENING. THIS CLOUD COVER MAY SPREAD EAST...AFFECTING THE KLBF
AND KVTN TERMINALS AFTER 06Z MONDAY. WINDS ARE EXPECTED TO BE LIGHT
FROM THE EAST AT 10 KTS OR LESS TODAY AND SOUTHEAST AT AROUND 10 KTS
TONIGHT AT BOTH TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 403 AM CDT SUN MAY 20 2012/
DISCUSSION...
STRONG UPPER LEVEL LOW CONTINUES TO MOVE ACROSS THE PLAINS...WITH
SOME LINGER CLOUDS OVER CENTRAL/EASTERN NEB STILL THIS
MORNING...HOWEVER SHOWERS HAVE PUSHED EAST OF THE CWA. AT THE
SURFACE HIGH PRESSURE IS BUILDING SOUTH ALONG THE FRONT RANGE OF
THE ROCKIES. LATEST HOURLY OBS SHOW TEMPS HAVE FALLEN INTO THE
40S WITH CLEAR SKIES IN THE WEST...WHILE HOLDING ONTO LOW 50S
BENEATH THE CLOUDS.
SYSTEM WILL CONTINUE TO PUSH EAST WHILE THE SURF HIGH BUILDS
ACROSS THE AREA. WINDS WILL BE LIGHT AND VARIABLE MOST OF THE
DAY...AND SWITCH TO THE SOUTH AS THE HIGH SHIFTS SOUTH OF THE ARE
AREA LATER TODAY. SEASONAL TEMPS EXPECTED FOR THE DAY...HIGHS
AROUND 70.
THIS AFTERNOON STEEP LAPSE RATE AND SOME MARGINAL INSTABILITY
/CAPE AROUND 500+ J/KG WITH LI/S CLOSE TO NEGATIVE ONE/ DEVELOP
OVER THE HIGHER TERRAIN OF THE FRONT RANGE. ISOLD TO SCT STORMS
EXPECTED WITH THE PEAK HEAT...THEN STORMS WILL MOVE EASTERLY WITH
ZONAL TO NW FLOW. ENERGY REMAINS OVER THE HIGHER TERRAIN WITH
SUBSIDENCE FROM THE HIGH. THIS SHOULD CAUSE THE STORMS TO DIE OFF
AS THE PUSH EAST...AND WILL GO DRY FOR THE CWA.
SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA MONDAY AND MONDAY
NIGHT. MODELS IN GOOD AGREEMENT WITH A NARROW BAND OF INSTABILITY
TO DEVELOP OVER THE CENTRAL PART OF THE CWA. CAP SHOULD BE WEAKEN
BY MID TO LATE AFTERNOON...HOWEVER MOISTURE IS QUESTIONABLE.
EXPECT A BROKEN LINE...MAYBE MORE ISOLATED STORMS...TO DEVELOP ON
THE TROUGH AS IT WORKS EAST DURING THE AFTERNOON. BETTER ENERGY IS
LOCATED ACROSS THE NORTHERN HALF OF THE CWA...WHICH WORKS EAST
INTO THE EVENING PERIOD.
ANOTHER WEAK SYSTEM WILL MOVE ACROSS THE AREA FOR WEDNESDAY. AGAIN
WILL NEED LOW POPS. SYSTEM IS SLOWER AND WILL CONTINUE POPS INTO
THURSDAY. STILL WARM TEMPS AS GUIDANCE IN THE 70S TO LOW 80S.
BY THE WEEKEND A RIDGE BUILDS ACROSS THE SOUTHEAST CONUS...WITH A
TROUGH DIGGING IN THE WEST. ECMWF HAS ALIGNED CLOSER TO THE GFS
AND ENSEMBLE MEAN WITH PLACEMENT OF THE RIDGE. NEBRASKA WILL BE IN
A TRANSITION ZONE...WITH HIGHS IN THE 90S...POSSIBLY MID OR
UPPER...TO THE SOUTHEAST...AND CLOSER TO 80 TO THE NORTHWEST. WILL
CONTINUE TO MONITOR AND HAVE BLENDED FORECAST. ALSO WITH THE
BOUNDARY IN THE AREA...WILL SEE THE CHANCE FOR THUNDERSTORMS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...MASEK
AVIATION...CLB
000
FXUS63 KGID 201050
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
550 AM CDT SUN MAY 20 2012
.AVIATION...12Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. SATELLITE IMAGERY INDICATES SKIES ARE CLEARING OUT
ACROSS SOUTH CENTRAL NEBRASKA...WITH CLEAR SKIES EXPECTED BY 15Z.
SURFACE WINDS WILL REMAIN FROM THE NORTH/NORTHWEST BUT WEAKEN
THROUGH THE DAY...BECOMING LIGHT AND VARIABLE OVERNIGHT. VISIBILITY
RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 440 AM CDT SUN MAY 20 2012/
SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
AVIATION/LONG TERM...BRYANT
000
FXUS63 KGID 200940
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
440 AM CDT SUN MAY 20 2012
.SHORT TERM...THROUGH TUESDAY NIGHT. OFFICIALLY...THE FORECAST
REMAINS DRY THROUGH THESE 72 HOURS. HOWEVER...THIS WILL NEED
WATCHED CLOSELY AS THERE ARE AT LEAST A FEW OPPORTUNITIES FOR
THUNDERSTORMS TO POTENTIALLY SNEAK INTO THE FORECAST. OF HIGHER
CONFIDENCE IS POSSIBLE ADVISORY-CRITERIA WINDS ON TUESDAY.
08Z OBJECTIVE SURFACE ANALYSIS PLACES THE CWA BETWEEN A 1010MB LOW
OVER WESTERN IA...AND A 1021MB HIGH STRETCHED NORTH-SOUTH ACROSS
THE PANHANDLE INTO EASTERN CO. AS A RESULT...BREEZES EARLY THIS
MORNING ARE LARGELY FROM THE WEST-NORTHWEST AREA WIDE...BUT
RANGING FROM VERY LIGHT IN THE FAR WESTERN COUNTIES...TO GUSTS
STILL AROUND 20 MPH IN THE EAST WHERE THE GRADIENT REMAINS
TIGHTEST. WATER VAPOR IMAGERY CLEARLY DEPICTS THE DEPARTING
SHORTWAVE RESPONSIBLE FOR YESTERDAY/S ROUND OF SEVERE WEATHER NOW
OVER NORTHEAST NEB...WITH BROAD QUASI-ZONAL FLOW ALOFT EXTENDING
BACK UPSTREAM TO THE EASTERN PACIFIC. RADAR AND 11-3.9 MICRON
SATELLITE IMAGERY CONFIRMS A STUBBORN AREA OF LINGERING LIGHT RAIN
THAT HAS FINALLY PUSHED OUT OF THE NORTHEASTERN CWA...IN ASSOCIATION
WITH THE PARENT AREA OF MID LEVEL CONVERGENCE/SATURATION ON THE
BACKSIDE OF THE EXITING SHORTWAVE. MEANWHILE...OFF TO THE SOUTH A
VERY NARROW BAND OF LIGHT RAIN/SPRINKLES IS MAKING ITS WAY ACROSS
PARTS OF CENTRAL KS...LIKELY DUE TO SOME SUBTLE MID LEVEL
FRONTOGENESIS IN THE ENTRANCE REGION OF A MID-UPPER JET STREAK
PULLING ACROSS NORTHERN KS/SOUTHEAST NEB.
FOLLOWING THE 05Z HRRR REFLECTIVITY CLOSELY...ALONG WITH LATEST
RADAR TRENDS...LOOKS LIKE ANY SPRINKLES IN NEB ZONES SHOULD
PRETTY MUCH BE GONE BY SUNRISE...SO WILL NOT CARRY A PRE-FIRST
PERIOD ZONE ISSUANCE TO COVER IT. AS FOR THE KS SPRINKLES...NOT
EXPECTING THESE TO BE AN ISSUE PAST SUNRISE EITHER...BUT WILL
CARRY A SLIGHT CHANCE SPRINKLE MENTION ACROSS THE FAR SOUTHERN CWA
THROUGH 12Z JUST IN CASE SOMETHING SNEAKS IN. OTHERWISE...A DRY
AND SEASONABLY PLEASANT DAY IS IN STORE. ALOFT...THE DEPARTING
SHORTWAVE AXIS WILL BE WELL UP INTO WESTERN WI BY 00Z...WITH
BROAD...MODESTLY AMPLIFIED RIDGING EXTENDING FROM THE WEST COAST
TO CENTRAL PLAINS IN ITS WAKE. AT THE SURFACE...A RIDGE AXIS WILL
GRADUALLY PASS ACROSS THE CWA THROUGH THE DAY...TRANSITIONING
WINDS FROM NORTHERLY THROUGH MUCH OF THE DAY TO MORE EASTERLY BY
DAY/S END. WITH THIS CENTER OF THIS HIGH TO THE NORTH OF THE AREA
THIS MORNING...THERE SHOULD BE AN INCREASE IN WIND SPEEDS MOST
AREAS AS BOUNDARY LAYER MIXING COMMENCES...WITH SUSTAINED SPEEDS
EASILY 10-15 MPH FOR SEVERAL HOURS...BEFORE SUBSIDING A BIT DURING
THE AFTERNOON. ALTHOUGH COULD SEE SOME LINGERING CLOUDS THIS
MORNING...AND MAYBE EVEN SOME DAYTIME FAIR WEATHER CUMULUS
DEVELOPMENT MAINLY IN EASTERN ZONES...THE CWA AS A WHOLE SHOULD
AVERAGE MOSTLY SUNNY TODAY. AS A RESULT...ANTICIPATE A FAIRLY
EFFICIENT WARM UP...AND KEPT HIGHS SIMILAR TO PREVIOUS
FORECAST...AND FAVORING THE WARMER MET GUIDANCE/RAW NAM SOLUTION
VERSUS COOLER MAV/GFS. THUS HAVE THE MAJORITY OF THE CWA REACHING
THE 72-76 RANGE.
TONIGHT...THE BROAD WESTERN TO CENTRAL CONUS RIDGE AMPLIFIES A
BIT...WITH MODEST MID LEVEL HEIGHT RISES OVER THE CENTRAL PLAINS
AS THE UPPER LEVEL FLOW BECOMES MORE NORTHERLY VERSUS WESTERLY
AROUND THE EASTERN PERIPHERY OF THE RIDGE. ALTHOUGH HAVE LEFT ALL
THUNDERSTORM MENTION OUT OF THE FORECAST FOR NOW...WILL HAVE TO KEEP
A CLOSE EYE ON FAR NORTHWEST ZONES AFTER MIDNIGHT AND ESPECIALLY
TOWARD SUNRISE...AS BOTH THE NAM/GFS ADVERTISE MODEST ELEVATED
THETA-E ADVECTION EVIDENT AT 700MB PUSHING EAST OUT OF WESTERN
NEB...ALONG WITH MAYBE UP TO A FEW HUNDRED J/KG MUCAPE ROOTED IN
THE 850-700MB LAYER. BOTH OF THESE MODELS KEEP CONVECTIVE QPF AT
LEAST SLIGHTLY NORTHWEST OF THE CWA OVER THE SANDHILLS...AND THE
00Z 4KM WRF-NMM SHOWS LITTLE HINT OF DEVELOPING CONVECTION...BUT
THIS WILL NEED CLOSELY WATCHED AS THIS KIND OF FORCING OFTEN LEADS
TO CLASSIC SUNRISE SURPRISE SHOWERS/WEAK STORMS. FOR LOW TEMPS
TONIGHT...WITH GENERALLY LIGHT EAST-SOUTHEAST BREEZES AND MOSTLY
CLEAR SKIES...OPTED TO LOWER LOWS 1-3 DEGREES FROM PREVIOUS
FORECAST...WITH MOST AREAS BETWEEN 44-48.
MONDAY...RIDGING WILL CONTINUE TO DOMINATE THE MID/UPPER
LEVELS...WITH THE AXIS GENERALLY ALIGNED ALONG THE ROCKIES...AND
CONTINUED NORTH-NORTHWEST FLOW ALOFT OVER THE CENTRAL PLAINS. AS
THE SURFACE RIDGE AXIS DEPARTS FARTHER EAST AND MODEST PRESSURE
FALLS OCCUR OVER THE HIGH PLAINS...SOUTHERLY WINDS WILL BECOME
ESTABLISHED...AND UPPED SUSTAINED SPEEDS SLIGHTLY WITH MOST OF THE
CWA SOLIDLY INTO THE 15-20 MPH RANGE MUCH OF THE DAY. DESPITE
MODEST LOW LEVEL MOISTURE RETURN WITH SURFACE DEWPOINTS POSSIBLY
APPROACHING 50 ACROSS THE WESTERN CWA...THE PRIMARY LOW LEVEL
INSTABILITY AXIS SHOULD SET UP AT LEAST 1-2 COUNTIES WEST OF THE
CWA DURING THE AFTERNOON...WITH THE NAM KEEPING ANY LATE AFTERNOON
CONVECTION SAFELY NORTHWEST OF THE AREA ACROSS THE SANDHILLS.
ASSUMING THAT NO SHOWERS/WEAK STORMS DO IN FACT DEVELOP EARLY IN
THE MORNING AS DISCUSSED ABOVE...HAVE FAIRLY HIGH CONFIDENCE IN
LEAVING STORMS OUT THROUGH THE AFTERNOON HOURS...DESPITE SPC
ASSIGNING A GENERAL THUNDER AREA TO MUCH OF THE WESTERN CWA ON THE
DAY2 OUTLOOK. WITH SOUTHERLY FLOW AND AFTERNOON MIXING TO AROUND
800MB PER NAM SOUNDINGS...KEPT HIGH TEMPS SIMILAR TO PREVIOUS
FORECAST...AND GENERALLY 2-4 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...WITH MOST AREAS 79-82.
MONDAY NIGHT...THE MID/UPPER RIDGE AXIS BECOMES MORE POSITIVELY
TILTED AND EXTENDS DIRECTLY THROUGH THE CENTRAL PLAINS...AS THE
RIDGE STARTS ITS EASTWARD PUSH IN RESPONSE TO AN INCOMING
SHORTWAVE AND ASSOCIATED UPPER JET STREAK MOVING INTO THE PACIFIC
NORTHWEST. ASSUMING THAT NO SANDHILLS CONVECTION SNEAKS INTO THE
CWA DURING THE EVENING...WILL STAY THE COURSE WITH A STORM-FREE
FORECAST THROUGH THE NIGHT...ALTHOUGH THIS WILL ALSO BEAR WATCHING
AS BOTH THE NAM/GFS ADVERTISE A BATCH OF ELEVATED INSTABILITY ON
THE ORDER OF 500-1000 J/KG SLIDING EAST OVER THE CWA DURING THE
NIGHT. THINKING AT THIS POINT IS THAT THESE PARCELS SHOULD REMAIN
CAPPED IN THE PRESENCE OF VERY LITTLE UPPER FORCING...WITH BETTER
CONVERGENCE ALONG THE NOSE OF THE LOW LEVEL JET AIMED MORE INTO
THE OAX CWA TOWARD THE MO RIVER...WHERE THE NAM ACTUALLY DOES
DEVELOP SOME CONVECTIVE QPF. CERTAINLY CANNOT COMPLETELY RULE OUT
A FEW SHOWERS/STORMS FLARING UP AND LATER SHIFTS MAY HAVE TO
CONSIDER ADDING A SLIGHT POP SOMEWHERE.
TUESDAY...INSTABILITY INCREASES FURTHER...AS SURFACE DEWPOINTS
CLIMB BACK INTO THE LOW-MID 50S...BUT WITH INCOMING NORTHWEST
CONUS SHORTWAVE REMAINING TO THE WEST...THIS SHOULD BE NOTHING
MORE THAN A WARM AND RATHER WINDY DAY...WITH NEAR-SURFACE PARCELS
CAPPED OFF AS SUGGESTED BY 700MB TEMPS INTO THE 11-13C RANGE. ANY
LATE AFTERNOON STORMS THAT MIGHT MANAGE TO DEVELOP IN THE REGION
SHOULD FOCUS WEST OF THE CWA NEARER THE PRIMARY SYNOPTIC DRYLINE.
AS A RESULT...EXPECT THE BIG STORY TUESDAY TO BE STRONG SOUTHERLY
WINDS...AS BOTH THE NAM/GFS DEEPEN A 989-992MB LOW OVER THE HIGH
PLAINS OVER THE COURSE OF THE DAY. THE RESULTANT STRENGTHENING
PRESSURE GRADIENT...ALONG WITH MIXING TO AT LEAST 750MB MOST
AREAS...SHOULD REALLY GET SOUTHERLY WINDS GOING. PREVIOUS FORECAST
ALREADY HAD PARTS OF THE AREA REACHING ADVISORY CRITERIA OF
SUSTAINED 30 MPH...AND GENERALLY KEPT THIS THEME INTACT...WITH THE
HIGHEST SPEEDS FOCUSED ACROSS THE WESTERN 1/2 OF THE CWA. WITH
THIS STILL BEING 5 PERIODS OUT...WAY TOO EARLY FOR A
HEADLINE...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER
OUTLOOK. EXPECTING MINIMAL CLOUD COVER...THIS SHOULD BE A CLASSIC
BIG WARM UP...DECENT DEWPOINT MIX-DOWN KIND OF DAY...AND HAVE
DEWPOINTS FALLING A BIT IN THE AFTERNOON...ESPECIALLY WEST. TEMP
WISE...NUDGED UP HIGHS 2-3 DEGREES FROM PREVIOUS FORECAST MOST
AREAS...AIMING FOR 89-92 MOST AREAS...AND EVEN MID 90S SOUTHWEST.
ALTHOUGH THIS IS SEVERAL DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...IT IS MORE IN LINE WITH RAW NAM TEMPS...AND DAYS LIKE
THIS HAVE PROVEN SEVERAL TIMES IN THE PAST FEW WEEKS THAT WARMER
IS THE WAY TO GO.
TUESDAY NIGHT...YET AGAIN KEPT THE AREA FREE OF STORM
MENTION...DESPITE THE GFS TRYING TO SNEAK SOME ACTIVITY INTO
NORTHEAST ZONES AFTER MIDNIGHT. DESPITE INCREASING FORCING FROM
THE INCOMING SHORTWAVE...MOST OF THIS ENERGY WILL REMAIN BACK OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS...AND BESIDES BOTH THE
NAM/GFS ADVERTISE A CONSIDERABLE CAPPING INVERSION WITH A 700MB
THERMAL RIDGE OF 13C+ SETTING UP OVER THE CWA DURING THE NIGHT.
NOT SURPRISINGLY...MODEL CONSENSUS IS TO FOCUS CONVECTION NORTH OF
THE CWA THROUGH THE NIGHT...NEAR AND JUST BEHIND AN INCOMING
SURFACE COLD FRONT AND IN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS.
WILL HAVE TO IRON OUT SOME DETAILS REGARDING THE SPEED OF THIS
INCOMING COLD FRONT HOWEVER...AS BY 12Z WEDNESDAY THE NAM ALREADY
HAS THE FRONT INTO THE WESTERN CWA...WHILE THE ECMWF STILL HAS IT
BACK IN WESTERN NEB. IF ANY STORMS DO MANAGE TO DEVELOP INTO THE
NORTHERN CWA DURING THE NIGHT...STRONG TO SEVERE IS CERTAINLY
POSSIBLE...BUT CONFIDENCE STILL REMAINS LOW ENOUGH REGARDING
STORM DEVELOPMENT TO KEEP POPS BELOW THE 20 PERCENT SLIGHT CHANCE
THRESHOLD.
.LONG TERM...TARTING 12Z WEDNESDAY. GUIDANCE FROM THE OPERATIONAL
GFS AND EC SUGGEST A MID LEVEL SHORT WAVE...PERHAPS A CLOSED LOW
PER THE GFS...WILL PUSH ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA WEDNESDAY AND THURSDAY. AN ASSOCIATED SURFACE LOW
IS ALSO EXPECTED TO PUSH EAST ACROSS THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THUS ALLOWING A LOW LEVEL BAROCLINIC ZONE TO PUSH
ACROSS OUR AREA DURING THE DAY WEDNESDAY. SURFACE RIDGING IS THEN
EXPECTED TO INFILTRATE THE CENTRAL PLAINS LATE WEDNESDAY THROUGH
EARLY FRIDAY BEFORE LOW LEVEL RETURN FLOW IS REALIZED ACROSS OUR
AREA LATE FRIDAY INTO SATURDAY.
THE OPERATIONAL GFS AND EC BOTH CONTINUE TO INDICATE CONVECTION
ALONG THE LOW LEVEL BAROCLINIC ZONE WEDNESDAY AFTERNOON AND EVENING.
THE OPERATIONAL GFS IS BECOMING SOMEWHAT MORE PROGRESSIVE AND NOW
SUGGESTS CONVECTION WILL FIRE EAST OF OUR CWA WELL AFTER THE LOW
LEVEL BAROCLINIC ZONE HAS CLEARED OUR AREA. THE EC ON THE OTHER HAND
SUGGESTS A SLIGHTLY SLOWER FROPA WITH CONVECTION POSSIBLE ALONG THE
EASTERN HALF OF OUR CWA LATE WEDNESDAY AFTERNOON INTO WEDNESDAY
EVENING. WITH 0-1KM MLCAPE VALUES PERHAPS APPROACHING 1500J/KG AND
DEEP LAYER BULK SHEAR VALUES IN THE NEIGHBORHOOD OF 40KTS...LARGE
HAIL AND PERHAPS STRONG WINDS CANNOT BE RULED OUT SHOULD
CONVECTION BE REALIZED OVER OUR AREA ALONG THE LOW LEVEL BAROCLINIC
ZONE WEDNESDAY. OPTED TO PLAY IT SAFE SINCE THE EC CONTINUES TO
SUGGEST THIS POSSIBILITY AND KEPT CONVECTION IN THE FORECAST ACROSS
THE EASTERN HALF OF THE CWA...WITH A SEVERE MENTION ALSO IN THE HWO
FOR LATE WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
MID AND UPPER LEVEL JET ENERGY IS EXPECTED TO PUSH OVERHEAD
THE CENTRAL PLAINS LATE WEDNESDAY...WITH THE LEFT-FRONT QUAD OF A
60-70KT MID LEVEL JET STREAK EXPECTED TO SET UP SHOP OVER OUR AREA
WEDNESDAY NIGHT INTO THURSDAY MORNING. AN INDIRECT THERMAL
CIRCULATION MAY PRODUCE ENOUGH LIFT FOR PRECIPITATION
PRODUCTION...ASSUMING ENOUGH LOW TO MID LEVEL MOISTURE...AND QPF
FIELDS FROM THE OPERATIONAL GFS AND EC BOTH SUGGEST PRECIPITATION
WILL BE REALIZED WEDNESDAY NIGHT/THURSDAY MORNING. WENT AHEAD WITH
POPS LATE WEDNESDAY INTO EARLY THURSDAY AS A RESULT. THE RIGHT-REAR
QUADRANT OF THE SAME MID LEVEL JET STREAK IS THEN EXPECTED TO PUSH
OVER NORTHERN PORTIONS OF THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING...THUS BRINGING ANOTHER CHANCE FOR PRECIPITATION TO NORTHERN
PORTIONS OF OUR AREA. THE INTRODUCTION OF A ~40KT LOW LEVEL JET
STREAK WILL THEN BRING FURTHER CHANCES OF PRECIPITATION TO THE AREA
FRIDAY NIGHT INTO EARLY SATURDAY. BEYOND WEDNESDAY EVENING...LOW
LEVEL MOISTURE IS NOT OVERLY IMPRESSIVE AS SURFACE RIDGING REMAINS
ENTRENCHED ACROSS THE AREA AND AS A RESULT...INSTABILITY SUFFERS
GREATLY. LOW LEVEL MOISTURE FINALLY IMPROVES BY LATE FRIDAY AS LOW
LEVEL RETURN FLOW IS REALIZED ACROSS THE AREA...WITH DEEP LAYER
MUCAPE VALUES PERHAPS CLIMBING TO AROUND 1000J/KG BY FRIDAY NIGHT.
GIVEN ALL THIS...AM NOT INCLINED TO GO WITH ANY SEVERE WORDING IN
THE HWO BEYOND WEDNESDAY EVENING.
A SUBTLE COOLING TREND SHOULD BE NOTED ACROSS THE AREA WEDNESDAY AND
THURSDAY AS SURFACE RIDGING REMAINS OVER THE AREA. LOW LEVEL RETURN
FLOW AND RESULTANT LOW LEVEL WARM AIR ADVECTION WILL THEN PROMOTE A
WARMING TREND TO FINISH OUT THE EXTENDED FORECAST PERIOD. DESPITE
ANY TRENDS...TEMPERATURES DURING THE EXTENDED FORECAST PERIOD WILL
REMAIN AT NEAR OR ABOVE-NORMAL LEVELS FOR THIS TIME OF YEAR.
&&
.PREV DISCUSSION... /ISSUED 1044 PM CDT SAT MAY 19 2012/
AVIATION...06Z KGRI TAF. MAY START OFF WITH MVFR CONDITIONS AS
LOWER CLOUDS JUST TO THE WEST WRAPPING AROUND MID LEVEL
CIRCULATION CURRENTLY OVERHEAD AND MOVING ENE. CLEAR SLOT SOUTH
WILL BE CLOSE AND WILL NEED TO MONITOR...AS WE SHOULD EVENTUALLY
BECOME VFR AND HOW QUICKLY DEPENDS ON EXTENT OF WRAP AROUND
CLOUDS. SHOULD SEE CLEAR SKIES FOR MOST OF THE DAYTIME AND
EVENING ON SUNDAY AS SURFACE HIGH PRESSURE MOVES EAST OVER THE
AREA WITH MUCH DRIER AIR AND SUBSIDENCE ALOFT. THIS WILL ALLOW
WINDS TO BE A LITTLE LIGHTER ON SUNDAY STARTING OUT FROM THE
NORTH...THEN NORTHEAST AND EVENTUALLY EASTERLY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
000
FXUS63 KLBF 200903
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
403 AM CDT SUN MAY 20 2012
.DISCUSSION...
STRONG UPPER LEVEL LOW CONTINUES TO MOVE ACROSS THE PLAINS...WITH
SOME LINGER CLOUDS OVER CENTRAL/EASTERN NEB STILL THIS
MORNING...HOWEVER SHOWERS HAVE PUSHED EAST OF THE CWA. AT THE
SURFACE HIGH PRESSURE IS BUILDING SOUTH ALONG THE FRONT RANGE OF
THE ROCKIES. LATEST HOURLY OBS SHOW TEMPS HAVE FALLEN INTO THE
40S WITH CLEAR SKIES IN THE WEST...WHILE HOLDING ONTO LOW 50S
BENEATH THE CLOUDS.
SYSTEM WILL CONTINUE TO PUSH EAST WHILE THE SURF HIGH BUILDS
ACROSS THE AREA. WINDS WILL BE LIGHT AND VARIABLE MOST OF THE
DAY...AND SWITCH TO THE SOUTH AS THE HIGH SHIFTS SOUTH OF THE ARE
AREA LATER TODAY. SEASONAL TEMPS EXPECTED FOR THE DAY...HIGHS
AROUND 70.
THIS AFTERNOON STEEP LAPSE RATE AND SOME MARGINAL INSTABILITY
/CAPE AROUND 500+ J/KG WITH LI/S CLOSE TO NEGATIVE ONE/ DEVELOP
OVER THE HIGHER TERRAIN OF THE FRONT RANGE. ISOLD TO SCT STORMS
EXPECTED WITH THE PEAK HEAT...THEN STORMS WILL MOVE EASTERLY WITH
ZONAL TO NW FLOW. ENERGY REMAINS OVER THE HIGHER TERRAIN WITH
SUBSIDENCE FROM THE HIGH. THIS SHOULD CAUSE THE STORMS TO DIE OFF
AS THE PUSH EAST...AND WILL GO DRY FOR THE CWA.
SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA MONDAY AND MONDAY
NIGHT. MODELS IN GOOD AGREEMENT WITH A NARROW BAND OF INSTABILITY
TO DEVELOP OVER THE CENTRAL PART OF THE CWA. CAP SHOULD BE WEAKEN
BY MID TO LATE AFTERNOON...HOWEVER MOISTURE IS QUESTIONABLE.
EXPECT A BROKEN LINE...MAYBE MORE ISOLATED STORMS...TO DEVELOP ON
THE TROUGH AS IT WORKS EAST DURING THE AFTERNOON. BETTER ENERGY IS
LOCATED ACROSS THE NORTHERN HALF OF THE CWA...WHICH WORKS EAST
INTO THE EVENING PERIOD.
ANOTHER WEAK SYSTEM WILL MOVE ACROSS THE AREA FOR WEDNESDAY. AGAIN
WILL NEED LOW POPS. SYSTEM IS SLOWER AND WILL CONTINUE POPS INTO
THURSDAY. STILL WARM TEMPS AS GUIDANCE IN THE 70S TO LOW 80S.
BY THE WEEKEND A RIDGE BUILDS ACROSS THE SOUTHEAST CONUS...WITH A
TROUGH DIGGING IN THE WEST. ECMWF HAS ALIGNED CLOSER TO THE GFS
AND ENSEMBLE MEAN WITH PLACEMENT OF THE RIDGE. NEBRASKA WILL BE IN
A TRANSITION ZONE...WITH HIGHS IN THE 90S...POSSIBLY MID OR
UPPER...TO THE SOUTHEAST...AND CLOSER TO 80 TO THE NORTHWEST. WILL
CONTINUE TO MONITOR AND HAVE BLENDED FORECAST. ALSO WITH THE
BOUNDARY IN THE AREA...WILL SEE THE CHANCE FOR THUNDERSTORMS.
&&
.AVIATION...
FOR THE KVTN AND KLBF TERMINALS THROUGH 12Z MONDAY.
THE UPPER LEVEL TROUGH OF LOW PRESSURE...RESPONSIBLE FOR
PRECIPITATION SATURDAY NIGHT...WILL TRACK INTO THE UPPER MISSISSIPPI
VALLEY TODAY. THIS WILL LEAD TO CLEARING SKIES ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA WITH SOME SCATTERED HIGH LEVEL CLOUDINESS AON
25000 FT AGL. DECAYING THUNDERSTORMS OVER EASTERN WYOMING AND THE
WESTERN NEBRASKA PANHANDLE...MAY RESULT IN SOME SCATTERED TO BROKEN
HIGH LEVEL CLOUDINESS OVER THE EASTERN NEBRASKA PANHANDLE AND
WESTERN NEBRASKA THIS EVENING. THIS CLOUD COVER MAY SPREAD
EAST...AFFECTING THE KLBF AND KVTN TERMINALS AFTER 06Z MONDAY. WINDS
ARE EXPECTED TO BE LIGHT FROM THE EAST AT 10 KTS OR LESS TODAY AND
TONIGHT AT BOTH TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...MASEK
AVIATION...CLB
000
FXUS63 KOAX 200800
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
300 AM CDT SUN MAY 20 2012
.DISCUSSION...
SHORTWAVE TROUGH THAT HELPED BRING THUNDERSTORMS TO THE AREA SATURDAY
CONTINUED TO LIFT NORTHEAST. HEIGHT FALLS ASSOCIATED WITH THIS
FEATURE WERE PRETTY WEAK...BUT DID HELP PUSH A COLD FRONT THROUGH
THE AREA. NORTH OR NORTHWEST WINDS TODAY WILL BRING IN COOLER AIR
COMPARED TO YESTERDAY...WITH HIGHS TODAY EXPECTED TO BE IN THE 70S.
A RIDGE OF HIGH PRESSURE AT THE SURFACE BUILDS OVER THE AREA THIS
AFTERNOON AND EVENING. THIS SHOULD ALLOW FOR DECENT RADIATIONAL
COOLING WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. LOWS ARE EXPECTED
TO DROP INTO THE 40S.
SOUTHERLY FLOW INCREASES ON MONDAY AND SHOULD HELP BRING LOW LEVEL
MOISTURE BACK INTO CENTRAL AND WESTERN NEBRASKA. 00Z GFS RUN THEN
BRINGS 850 MB DEWPOINTS OF 6-12 DEGREES CELSIUS INTO NORTHEAST
NEBRASKA MONDAY NIGHT. FELT THAT THE GFS HAD A DECENT HANDLE ON THE
SITUATION AND IT DID DEVELOP SOME PRECIPITATION. AT THIS POINT...DID
NOT FAVOR THE 00Z NAM SOLUTION WHICH DEVELOPED PRECIPITATION INTO
SOUTHWEST IOWA AND PARTS OF SOUTHEAST NEBRASKA AFTER MIDNIGHT MONDAY
NIGHT. A COLD FRONT WILL BE PUSHING EASTWARD ACROSS THE NORTHERN
PLAINS TUESDAY NIGHT AND COULD HELP TRIGGER SHOWERS OR THUNDERSTORMS
FOR PARTS OF NORTHEAST NEBRASKA AFTER MIDNIGHT. FELT THINGS LOOKED
BETTER FARTHER NORTH...SO DID NOT MENTION ANY SHOWERS TUESDAY
NIGHT. THIS WILL NEED TO BE MONITORED FOR FUTURE UPDATES.
THE PATTERN MID WEEK SHOULD FEATURE A TROUGH OVER THE ROCKIES WHICH
WILL PARTIALLY LIFT OUT INTO THE NORTHERN PLAINS THURSDAY. AT THE
SAME TIME...A DEEPER TROUGH/CLOSED LOW WILL BE DIGGING ALONG THE
WEST COAST. ALTHOUGH THE MODELS AGREE ON THE GENERAL PATTERN...THE
12Z ECMWF SHOWED A 500 MB RIDGE CENTERED OVER MISSOURI...WHILE THE
00Z GFS HAD THE HIGH FARTHER SOUTHEAST. TELECONNECTIONS TENDED TO
SUPPORT THE GFS SOLUTION...WHICH ALSO HAD SOME SUPPORT FROM THE
CANADIAN GEM. NOT SURPRISINGLY...THE 00Z ECMWF SOLUTION TRENDED
MORE TOWARD THE GFS. GENERALLY USED A BLEND OF 00Z GFS AND 00Z
ECMWF FOR DAYS 4 TO 7.
MILLER
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...AND KOFK.
COLD FRONT THAT INDUCED WIDESPREAD CONVECTION EARLIER TONIGHT HAS
PUSHED PASSED THE I-80 CORRIDOR AND CONTINUES TO MOVE SOUTH INTO
IA/MO/KS. POST-FRONTAL TSRA ACTIVITY OVER NERN NEB WILL CONTINUE
INTO LIFT NEWD WITH UPPER LEVEL DISTURBANCE. MAIN CONCERN THEN IS
MVFR CIGS SETTLING IN THIS MORNING. EXPECT LOWER CLOUD COVER
PRESENTLY OVER CNTRL NEB TO PIVOT INTO ERN NEB AS UPPER DISTURTBANCE
LIFTS NORTHEAST. MVFR CIGS HAVE ALREADY OCCUPIED KOFK AND SHOULD
REMAIN SO UNTIL 11Z...VFR THEREAFTER. AS FOR KOMA/KLNK...TIME PD FOR
MVFR CIGS WILL BE RELATIVELY BRIEF...BTWN 10Z-13Z. VFR AFTERWARDS AT
KOMA/KLNK.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KLBF 200522 AAA
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1222 AM CDT SUN MAY 20 2012
.AVIATION...
FEW SHOWERS LINGER OVER NORTH CENTRAL NEBRASKA WITH SKIES CLEARING
OUT OVER THE PANHANDLE. CLOUDS DECREASING OVER THE REMAINDER OF THE
WEST. MAY BE SOME GROUND FOG AT BOTH KLBF AND KVTN SUNDAY MORNING AS
TEMPERATURES FALL. CONFIDENCE IS NOT HIGH AND HAVE CHOSE NOT TO
INCLUDE AT THIS TIME. LIGHT NORTHERLY WINDS OVER WESTERN NEBRASKA
SUNDAY WITH PARTLY CLOUDY SKIES AND VISUAL FLIGHT RULES.
&&
.PREV DISCUSSION... /ISSUED 648 PM CDT SAT MAY 19 2012/
DISCUSSION...
POTENT UPPER LEVEL TROF LOCATED ACROSS SERN WY...NERN COLO AND
SWRN NEB THIS AFTN WILL ROTATE NORTHEAST THROUGH THE FCST AREA THIS
EVENING. THE GENERAL CONSENSUS AMONG THE MODEL DATA AND RADAR
SUGGESTS THE ONGOING AREA OF SHOWERS AND TSTMS WILL LIFT NORTHEAST
THROUGH THE FCST AREA BY MIDNIGHT WITH JUST ISOLATED SHOWERS AND
THUNDERSTORMS AFTER MIDNIGHT IN THE NORTHEAST CORNER OF THE FCST AREA.
ONGOING ISOLATED LARGE HAIL IS POSSIBLE GENERALLY ALONG AND EAST
OF HIGHWAY 183. SFC HIGH PRESSURE WILL BUILD INTO THE FCST AREA BY
SUNDAY MORNING WITH SUNNY...SEASONABLE TEMPS AND LIGHT WINDS. VERY
QUICKLY...THE HIGH WILL MOVE OFF TO THE EAST ON MONDAY WITH SRLY
RETURN DEVELOPING ACROSS THE HIGH PLAINS IN RESPONSE TO LOW
PRESSURE DEVELOPING ACROSS THE NRN HIGH PLAINS. THIS LOW IS
EXPECTED TO DEEPEN TO NEAR 989 MB TUESDAY AFTERNOON VICINITY THE
BLK HILLS AND TRACK INTO CNTL SD BY TUESDAY EVENING. THE RESULT
SHOULD BE A PERIOD OF WINDY CONDITIONS AND STRONG WARM AIR
ADVECTION TUESDAY. THIS COULD PUSH HIGHS INTO THE LOWER 90S WITH
SOUTH WINDS INCREASING TO 25 TO 30 MPH.
MEANWHILE THE NAM SUGGESTED K INDICES WOULD RISE INTO THE 30S
MONDAY AFTERNOON ACROSS A SLIVER OF WRN AND NCNTL NEB. COOL
WEST-NORTHWEST FLOW ALOFT AND A WEAK DISTURBANCE MIGHT BE ENOUGH
FOR ISOLATED TSTMS MONDAY AFTERNOON AND EVENING. THE ATMOSPHERE
SHOULD BE STRONGLY CAPPED TUESDAY AFTN/EVENING AS H700 MB TEMPS
RISE TO AROUND 12C. THE GFS AND ECM THEN PASS A DRY COLD FRONT
THROUGH THE FCST AREA LATE TUESDAY NIGHT.
THE RETURN MOISTURE MONDAY NIGHT MIGHT BE SUFFICIENT FOR A PERIOD
OF MORNING STRATUS TUESDAY. BURNOFF SHOULD BE BY MID MORNING AS
MOISTURE PROFILES APPEAR TO BE FAIRLY SHALLOW.
WEDNESDAY THROUGH SATURDAY...A DEVELOPING TROUGH ACROSS THE WESTERN
CONUS WILL BECOME ESTABLISHED BY FRIDAY INTO SATURDAY. MEANWHILE A
SPRAWLING UPPER LEVEL RIDGE OF HIGH PRESSURE WILL DEVELOP ACROSS THE
CENTRAL PLAINS EASTWARD. MODELS DIFFER SOMEWHAT ON EXACTLY HOW
STRONG AND FAR WEST THE UPPER LEVEL HIGH PRESSURE WILL EXTEND. THE
ECMWF IS THE FARTHEST WEST...AND PRETTY MUCH HAS MOST OF WESTERN AND
NORTH CENTRAL NEBRASKA IN INTENSE HEAT AND DRY CONDITIONS BY
MEMORIAL DAY WEEKEND. THE ENSEMBLE MEAN BUILDS THE HIGH AS WELL...BUT
KEEPS IT FARTHER EAST. THIS WOULD ALLOW FOR MORE INFLUENCE FROM THE
WESTERN CONUS TROUGH AND THE POSSIBILITY OF T-STORMS.
AT THIS TIME WILL CONTINUE THE CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY INTO THURSDAY WITH A COLD FRONTAL PASSAGE. THE FRONT WILL
STALL JUST TO OUR SOUTH AS THE UPPER TROUGH DEVELOPS TO THE WEST.
THE FRONT THEN LIFTS NORTH FRIDAY AS A WARM FRONT. WILL TREND TEMPS
UP SOME FRIDAY INTO SATURDAY...AND KEEP CHANCES FOR STORMS AT SLIGHT
CHANCES DUE TO THE AFOREMENTIONED MODEL DIFFERENCES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
000
FXUS63 KOAX 200452 AAA
AFDOAX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1152 PM CDT SAT MAY 19 2012
.UPDATE...
.AVIATION... 06Z TAFS FOR KOMA...KLNK...AND KOFK.
COLD FRONT THAT INDUCED WIDESPREAD CONVECTION EARLIER TONIGHT HAS
PUSHED PASSED THE I-80 CORRIDOR AND CONTINUES TO MOVE SOUTH INTO
IA/MO/KS. POST-FRONTAL TSRA ACTIVITY OVER NERN NEB WILL CONTINUE
INTO LIFT NEWD WITH UPPER LEVEL DISTURBANCE. MAIN CONCERN THEN IS
MVFR CIGS SETTLING IN THIS MORNING. EXPECT LOWER CLOUD COVER
PRESENTLY OVER CNTRL NEB TO PIVOT INTO ERN NEB AS UPPER
DISTURTBANCE LIFTS NORTHEAST. MVFR CIGS HAVE ALREADY OCCUPIED KOFK
AND SHOULD REMAIN SO UNTIL 11Z...VFR THEREAFTER. AS FOR
KOMA/KLNK...TIME PD FOR MVFR CIGS WILL BE RELATIVELY BRIEF...BTWN
10Z-13Z. VFR AFTERWARDS AT KOMA/KLNK.
DEE
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT SAT MAY 19 2012/
DISCUSSION...
A COLD FRONT WAS LOCATED OVER PARTS OF NORTHEAST INTO SOUTH
CENTRAL NEBRASKA AT 19Z. THE FRONT WILL MOVE SOUTHEAST ACROSS THE
AREA TONIGHT WITH SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
MIDNIGHT. THE FRONT AND ASSOCIATED THUNDERSTORMS WILL BE EAST OF
THE AREA ON SUNDAY WITH COOLER TEMPERATURES EXPECTED AS HIGH
PRESSURE BUILDS INTO THE REGION THROUGH MONDAY. INCREASING
SOUTHERLY FLOW THEN RETURNS MONDAY NIGHT THROUGH TUESDAY IN
ADVANCE OF ANOTHER COLD FRONT MOVING INTO THE WESTERN HIGH PLAINS.
THIS SECOND COLD FRONT IS EXPECTED TO MOVE INTO THE AREA ON
WEDNESDAY THEN STALL OUT OVER SOUTHEAST NEBRASKA WEDNESDAY NIGHT.
EXTENDED MODELS THEN DIFFER ON THE SOLUTION FOR THE REMAINDER OF
THE WEEK AS THE GFS KEEPS THE STALLED BOUNDARY NEAR THE KANSAS
BORDER WITH THE CHANCE OF MORE THUNDERSTORMS FOR THE AREA. THE
ECMWF MEANWHILE LIFTS IT NORTH AS A WARM FRONT BY FRIDAY WITH
SIGNIFICANTLY WARMER TEMPERATURES INDICATED FOR THE WEEKEND.
AS A RESULT LOW CONFIDENCE AT THIS TIME FOR THIS PORTION OF THE
EXTENDED PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KGID 200344
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1044 PM CDT SAT MAY 19 2012
.AVIATION...06Z KGRI TAF. MAY START OFF WITH MVFR CONDITIONS AS
LOWER CLOUDS JUST TO THE WEST WRAPPING AROUND MID LEVEL
CIRCULATION CURRENTLY OVERHEAD AND MOVING ENE. CLEAR SLOT SOUTH
WILL BE CLOSE AND WILL NEED TO MONITOR...AS WE SHOULD EVENTUALLY
BECOME VFR AND HOW QUICKLY DEPENDS ON EXTENT OF WRAP AROUND
CLOUDS. SHOULD SEE CLEAR SKIES FOR MOST OF THE DAYTIME AND
EVENING ON SUNDAY AS SURFACE HIGH PRESSURE MOVES EAST OVER THE
AREA WITH MUCH DRIER AIR AND SUBSIDENCE ALOFT. THIS WILL ALLOW
WINDS TO BE A LITTLE LIGHTER ON SUNDAY STARTING OUT FROM THE
NORTH...THEN NORTHEAST AND EVENTUALLY EASTERLY.
&&
.PREV DISCUSSION... /ISSUED 226 PM CDT SAT MAY 19 2012/
SHORT TERM...REST OF TODAY THROUGH SUNDAY. PRIMARY FORECAST
CONCERN LIES WITH THUNDERSTORM CHANCES THROUGH THIS EVENING.
UPPER LEVEL PROFILER AND SATELLITE DATA NOT SHOWING ANY SURPRISES
EARLY THIS AFTERNOON...WITH THE SYSTEM OF INTEREST STARTING TO
PUSH OUT OF CO AND ONTO THE PLAINS...AND ACTIVITY IS ALREADY
ONGOING ACROSS PORTIONS OF SWRN NEB/WRN KS AND MOVING TOWARD THE
WRN EDGE OF THE CWA. AT THE SFC...MAIN FRONT MADE PRETTY GOOD
EASTWARD PROGRESS THIS MORNING...MAKING IT ABOUT HALFWAY THROUGH
THE CWA...WHERE IT HAS SINCE SLOWED/STALLED OUT. WARMER MID LEVEL
TEMPS HAVE KEPT THE AREA IN THE PROXIMITY OF THE FRONT CAPPED OFF
SO FAR...BUT THAT ISNT EXPECTED TO LAST TOO MUCH LONGER AS THE
UPPER LEVEL TROUGH APPROACHES. EVEN WITH PLENTY OF CLOUD COVER IN
PLACE...TEMPS CLIMBING WELL INTO THE 70S AND LOWER 80S ALONG WITH
DEWPOINTS APPROACHING/AT 60 DEGREES HAS RESULTED IN INSTABILITY
VALUES NEAR/+ 2000 J/KG ALONG AND AHEAD OF THE FRONT WITH WEAKER
SHEAR...WITH LESS INSTABILITY BUT BETTER SHEAR SET UP BEHIND THE
FRONT.
THIS SURFACE FRONT WILL REMAIN THE PRIMARY FOCUS FOR CONVECTIVE
DEVELOPMENT THIS AFTERNOON/EVENING...BUT WILL ALSO HAVE TO KEEP AN
EYE ON THE ONGOING ELEVATED ACTIVITY TO THE WEST. SHORT TERM/HIRES
MODELS REMAIN IN GOOD AGREEMENT SHOWING THE E/SE HALF OF THE CWA
BEING PRIMARILY IMPACTED BY ANY ACTIVITY ASSOCIATED WITH THE
FRONT...WHERE HAIL/WIND AND AN ISO TOR WILL REMAIN A CONCERN.
HAIL/WIND WOULD BE THE CONCERNS WITH THE ACTIVITY FURTHER WEST.
PRECIPITATION IS EXPECTED SHIFT OFF TO THE E/NE...AND SHIFT OUT
OF THE CWA NEAR/IF NOT BEFORE MIDNIGHT.
ONCE WE GET PAST MIDNIGHT TONIGHT AND THROUGH TOMORROW...DRY
FORECAST REMAINS IN PLACE...WITH SLIGHT NORTHWESTERLY FLOW SETTING
UP IN THE UPPER LEVELS BEHIND THIS LATEST TROUGH AXIS AND AHEAD OF
WEAK RIDGING DEVELOPING OVER THE ROCKIES. ONCE THE SFC FRONT
PUSHES OUT OF THE CWA...HIGH PRESSURE SETTLES IN FROM THE
WEST...AND IS EXPECTED TO BE CENTERED OVER THE CENTRAL PLAINS
THROUGH THE DAY. THIS WILL KEEP WINDS GENERALLY NORTHERLY...WITH
SPEEDS ARND 10 MPH...AND WITH COOLER AIR ACCOMPANYING THIS SFC
HIGH...TEMPERATURES ARE EXPECTED TO `ONLY` TOP OUT IN THE LOW/MID
70S...OR NEAR AVERAGE FOR THIS TIME OF YEAR.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
FOR SUNDAY THROUGH TUESDAY NIGHT...UPPER LEVEL RIDGING SHOULD BE A
STRONG INFLUENCE ON KEEP OUR WEATHER DRY WITH A SURFACE TROUGH
IN THE LEE OF THE ROCKY MOUNTAINS DEVELOPING DURING THIS PERIOD.
TUESDAY MAY VERY WELL BE THE WARMEST DAY WITH 850 MB BEING THE
WARMEST AHEAD OF LEE TROUGH AND AN APPROACHING COLD FRONT.
ALSO...TUESDAY AFTERNOON WILL BE QUITE WINDY WITH AN INCREASING
PRESSURE GRADIENT...ESPECIALLY WEST OF HIGHWAY 281.
THE UPPER LEVEL PATTERN BECOMES QUITE AMPLIFIED BY WEDNESDAY.
MODELS ARE IN GOOD AGREEMENT THAT A MEAN LONGWAVE TROUGH
DEVELOPS IN THE WESTERN UNITED STATES AND A LONGWAVE RIDGE TO THE
EAST. THE GFS IS MORE EARLY AND AGGRESSIVE THAN THE ECMWF AT
EJECTING PIECES OF ENERGY INTO THE PLAINS...WHICH WILL LEAD TO AT
LEAST LOW CHANCES OF PRECIPITATION FROM WEDNESDAY INTO THE REST OF
THE LONG TERM FORECAST. AT THE SURFACE...A WARM FRONT IS FORECAST
TO PASS EAST OF THE CWA BY SOMETIME WEDNESDAY...WITH A COLD FRONT
IN WESTERN NEBRASKA PREDICTED TO STALL SOMEWHERE JUST WEST OF THE
CWA. THE RIDGE TO THE EAST OF THE CWA SHOULD SHUNT MOISTURE RETURN
TO AT LEAST SOME EXTENT...CALLING INTO QUESTION THE CHANCES OF
SEVERE WEATHER AND FOR THAT MATTER...PRECIPITATION. MOISTURE
SHOULD EVENTUALLY MAKE A RETURN WITH THE STALLED BOUNDARY HANGING
AROUND THE REGION INTO THE WEEKEND. DETERMINING SEVERE CHANCES
WILL BE DICEY...BUT STORMS WEDNESDAY AFTERNOON AND EVENING COULD
BE STRONG TO SEVERE...ESPECIALLY AS THE LOW-LEVEL JET KICKS IN
WEDNESDAY EVENING. THE PLACEMENT OF THE BAROCLINIC ZONE WILL BE
CRUCIAL IN DETERMINING SEVERE WEATHER CHANCES FURTHER OUT THAN
WEDNESDAY. SHEAR NEAR THE BOUNDARY SHOULD BE AMPLE FOR SEVERE
WEATHER...BUT INSTABILITY SEEMS TO BE THE LIMITING FACTOR HERE.
NORTHERN AND WESTERN AREAS OF THE CWA HAVE POTENTIAL TO BE COOLER
THAN THE REST IF THE BOUNDARY DRAPES INTO OUR CWA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLBF 192348 AAA
AFDLBF
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
648 PM CDT SAT MAY 19 2012
.AVIATION...
THUNDERSTORMS OVER CENTRAL AND EASTERN NEBRASKA EAST OF A LINE FROM
KANW TO KBBW WITH MVFR CEILINGS OVER WESTERN NEBRASKA. CIGS TO
IMPROVE THROUGH VFR BY 2006Z. THEN CLEARING SKIES THROUGH THE
MORNING WITH LIGHT NORTHERLY WINDS.
&&
.PREV DISCUSSION... /ISSUED 345 PM CDT SAT MAY 19 2012/
DISCUSSION...
POTENT UPPER LEVEL TROF LOCATED ACROSS SERN WY...NERN COLO AND
SWRN NEB THIS AFTN WILL ROTATE NORTHEAST THROUGH THE FCST AREA THIS
EVENING. THE GENERAL CONSENSUS AMONG THE MODEL DATA AND RADAR
SUGGESTS THE ONGOING AREA OF SHOWERS AND TSTMS WILL LIFT NORTHEAST
THROUGH THE FCST AREA BY MIDNIGHT WITH JUST ISOLATED SHOWERS AND
THUNDERSTORMS AFTER MIDNIGHT IN THE NORTHEAST CORNER OF THE FCST AREA.
ONGOING ISOLATED LARGE HAIL IS POSSIBLE GENERALLY ALONG AND EAST
OF HIGHWAY 183. SFC HIGH PRESSURE WILL BUILD INTO THE FCST AREA BY
SUNDAY MORNING WITH SUNNY...SEASONABLE TEMPS AND LIGHT WINDS. VERY
QUICKLY...THE HIGH WILL MOVE OFF TO THE EAST ON MONDAY WITH SRLY
RETURN DEVELOPING ACROSS THE HIGH PLAINS IN RESPONSE TO LOW
PRESSURE DEVELOPING ACROSS THE NRN HIGH PLAINS. THIS LOW IS
EXPECTED TO DEEPEN TO NEAR 989 MB TUESDAY AFTERNOON VICINITY THE
BLK HILLS AND TRACK INTO CNTL SD BY TUESDAY EVENING. THE RESULT
SHOULD BE A PERIOD OF WINDY CONDITIONS AND STRONG WARM AIR
ADVECTION TUESDAY. THIS COULD PUSH HIGHS INTO THE LOWER 90S WITH
SOUTH WINDS INCREASING TO 25 TO 30 MPH.
MEANWHILE THE NAM SUGGESTED K INDICES WOULD RISE INTO THE 30S
MONDAY AFTERNOON ACROSS A SLIVER OF WRN AND NCNTL NEB. COOL
WEST-NORTHWEST FLOW ALOFT AND A WEAK DISTURBANCE MIGHT BE ENOUGH
FOR ISOLATED TSTMS MONDAY AFTERNOON AND EVENING. THE ATMOSPHERE
SHOULD BE STRONGLY CAPPED TUESDAY AFTN/EVENING AS H700 MB TEMPS
RISE TO AROUND 12C. THE GFS AND ECM THEN PASS A DRY COLD FRONT
THROUGH THE FCST AREA LATE TUESDAY NIGHT.
THE RETURN MOISTURE MONDAY NIGHT MIGHT BE SUFFICIENT FOR A PERIOD
OF MORNING STRATUS TUESDAY. BURNOFF SHOULD BE BY MID MORNING AS
MOISTURE PROFILES APPEAR TO BE FAIRLY SHALLOW.
WEDNESDAY THROUGH SATURDAY...A DEVELOPING TROUGH ACROSS THE WESTERN
CONUS WILL BECOME ESTABLISHED BY FRIDAY INTO SATURDAY. MEANWHILE A
SPRAWLING UPPER LEVEL RIDGE OF HIGH PRESSURE WILL DEVELOP ACROSS THE
CENTRAL PLAINS EASTWARD. MODELS DIFFER SOMEWHAT ON EXACTLY HOW
STRONG AND FAR WEST THE UPPER LEVEL HIGH PRESSURE WILL EXTEND. THE
ECMWF IS THE FARTHEST WEST...AND PRETTY MUCH HAS MOST OF WESTERN AND
NORTH CENTRAL NEBRASKA IN INTENSE HEAT AND DRY CONDITIONS BY
MEMORIAL DAY WEEKEND. THE ENSEMBLE MEAN BUILDS THE HIGH AS WELL...BUT
KEEPS IT FARTHER EAST. THIS WOULD ALLOW FOR MORE INFLUENCE FROM THE
WESTERN CONUS TROUGH AND THE POSSIBILITY OF T-STORMS.
AT THIS TIME WILL CONTINUE THE CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY INTO THURSDAY WITH A COLD FRONTAL PASSAGE. THE FRONT WILL
STALL JUST TO OUR SOUTH AS THE UPPER TROUGH DEVELOPS TO THE WEST.
THE FRONT THEN LIFTS NORTH FRIDAY AS A WARM FRONT. WILL TREND TEMPS
UP SOME FRIDAY INTO SATURDAY...AND KEEP CHANCES FOR STORMS AT SLIGHT
CHANCES DUE TO THE AFOREMENTIONED MODEL DIFFERENCES.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...POWER
000
FXUS63 KLBF 192046
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
345 PM CDT SAT MAY 19 2012
.DISCUSSION...
POTENT UPPER LEVEL TROF LOCATED ACROSS SERN WY...NERN COLO AND
SWRN NEB THIS AFTN WILL ROTATE NORTHEAST THROUGH THE FCST AREA THIS
EVENING. THE GENERAL CONSENSUS AMONG THE MODEL DATA AND RADAR
SUGGESTS THE ONGOING AREA OF SHOWERS AND TSTMS WILL LIFT NORTHEAST
THROUGH THE FCST AREA BY MIDNIGHT WITH JUST ISOLATED SHOWERS AND
THUNDERSTORMS AFTER MIDNIGHT IN THE NORTHEAST CORNER OF THE FCST AREA.
ONGOING ISOLATED LARGE HAIL IS POSSIBLE GENERALLY ALONG AND EAST
OF HIGHWAY 183. SFC HIGH PRESSURE WILL BUILD INTO THE FCST AREA BY
SUNDAY MORNING WITH SUNNY...SEASONABLE TEMPS AND LIGHT WINDS. VERY
QUICKLY...THE HIGH WILL MOVE OFF TO THE EAST ON MONDAY WITH SRLY
RETURN DEVELOPING ACROSS THE HIGH PLAINS IN RESPONSE TO LOW
PRESSURE DEVELOPING ACROSS THE NRN HIGH PLAINS. THIS LOW IS
EXPECTED TO DEEPEN TO NEAR 989 MB TUESDAY AFTERNOON VICINITY THE
BLK HILLS AND TRACK INTO CNTL SD BY TUESDAY EVENING. THE RESULT
SHOULD BE A PERIOD OF WINDY CONDITIONS AND STRONG WARM AIR
ADVECTION TUESDAY. THIS COULD PUSH HIGHS INTO THE LOWER 90S WITH
SOUTH WINDS INCREASING TO 25 TO 30 MPH.
MEANWHILE THE NAM SUGGESTED K INDICES WOULD RISE INTO THE 30S
MONDAY AFTERNOON ACROSS A SLIVER OF WRN AND NCNTL NEB. COOL
WEST-NORTHWEST FLOW ALOFT AND A WEAK DISTURBANCE MIGHT BE ENOUGH
FOR ISOLATED TSTMS MONDAY AFTERNOON AND EVENING. THE ATMOSPHERE
SHOULD BE STRONGLY CAPPED TUESDAY AFTN/EVENING AS H700 MB TEMPS
RISE TO AROUND 12C. THE GFS AND ECM THEN PASS A DRY COLD FRONT
THROUGH THE FCST AREA LATE TUESDAY NIGHT.
THE RETURN MOISTURE MONDAY NIGHT MIGHT BE SUFFICIENT FOR A PERIOD
OF MORNING STRATUS TUESDAY. BURNOFF SHOULD BE BY MID MORNING AS
MOISTURE PROFILES APPEAR TO BE FAIRLY SHALLOW.
WEDNESDAY THROUGH SATURDAY...A DEVELOPING TROUGH ACROSS THE WESTERN
CONUS WILL BECOME ESTABLISHED BY FRIDAY INTO SATURDAY. MEANWHILE A
SPRAWLING UPPER LEVEL RIDGE OF HIGH PRESSURE WILL DEVELOP ACROSS THE
CENTRAL PLAINS EASTWARD. MODELS DIFFER SOMEWHAT ON EXACTLY HOW
STRONG AND FAR WEST THE UPPER LEVEL HIGH PRESSURE WILL EXTEND. THE
ECMWF IS THE FARTHEST WEST...AND PRETTY MUCH HAS MOST OF WESTERN AND
NORTH CENTRAL NEBRASKA IN INTENSE HEAT AND DRY CONDITIONS BY
MEMORIAL DAY WEEKEND. THE ENSEMBLE MEAN BUILDS THE HIGH AS WELL...BUT
KEEPS IT FARTHER EAST. THIS WOULD ALLOW FOR MORE INFLUENCE FROM THE
WESTERN CONUS TROUGH AND THE POSSIBILITY OF T-STORMS.
AT THIS TIME WILL CONTINUE THE CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY INTO THURSDAY WITH A COLD FRONTAL PASSAGE. THE FRONT WILL
STALL JUST TO OUR SOUTH AS THE UPPER TROUGH DEVELOPS TO THE WEST.
THE FRONT THEN LIFTS NORTH FRIDAY AS A WARM FRONT. WILL TREND TEMPS
UP SOME FRIDAY INTO SATURDAY...AND KEEP CHANCES FOR STORMS AT SLIGHT
CHANCES DUE TO THE AFOREMENTIONED MODEL DIFFERENCES.
&&
.AVIATION...
AN UPPER LEVEL DISTURBANCE WILL MOVE NORTHEAST ACROSS THE AREA THIS
AFTERNOON AND EVENING. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS
DISTURBANCE...AND MOSTLY IMPACT AREAS ALONG AND SOUTH OF A LINE FROM
KANW TO KSNY. IT IS POSSIBLE THAT SOME SHOWERS COULD DEVELOP NORTH
OF THIS LINE...AND WILL MONITOR. THUNDERSTORMS CURRENTLY IN THE KLBF
AREA WILL EXIT BY 21Z...WITH SOME LINGERING LIGHT RAIN TILL AROUND
00Z. AT THIS TIME...EXPECTING MOST OF THE ACTIVITY TO STAY SOUTH AND
EAST OF THE KVTN TAF SITE...BUT AGAIN MONITOR IN CASE SHOWERS
DEVELOP FARTHER TO THE NORTH. OUTSIDE OF PRECIPITATION...WIDESPREAD
MVFR CEILINGS CAN BE EXPECTED DUE TO STRATUS. SFC WINDS WILL BE
NORTH AT 15 TO 25 KTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CDC
AVIATION/EXTENDED...TAYLOR
000
FXUS63 KOAX 192012
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
312 PM CDT SAT MAY 19 2012
.DISCUSSION...
A COLD FRONT WAS LOCATED OVER PARTS OF NORTHEAST INTO SOUTH
CENTRAL NEBRASKA AT 19Z. THE FRONT WILL MOVE SOUTHEAST ACROSS THE
AREA TONIGHT WITH SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
MIDNIGHT. THE FRONT AND ASSOCIATED THUNDERSTORMS WILL BE EAST OF
THE AREA ON SUNDAY WITH COOLER TEMPERATURES EXPECTED AS HIGH
PRESSURE BUILDS INTO THE REGION THROUGH MONDAY. INCREASING
SOUTHERLY FLOW THEN RETURNS MONDAY NIGHT THROUGH TUESDAY IN
ADVANCE OF ANOTHER COLD FRONT MOVING INTO THE WESTERN HIGH PLAINS.
THIS SECOND COLD FRONT IS EXPECTED TO MOVE INTO THE AREA ON
WEDNESDAY THEN STALL OUT OVER SOUTHEAST NEBRASKA WEDNESDAY NIGHT.
EXTENDED MODELS THEN DIFFER ON THE SOLUTION FOR THE REMAINDER OF
THE WEEK AS THE GFS KEEPS THE STALLED BOUNDARY NEAR THE KANSAS
BORDER WITH THE CHANCE OF MORE THUNDERSTORMS FOR THE AREA. THE
ECMWF MEANWHILE LIFTS IT NORTH AS A WARM FRONT BY FRIDAY WITH
SIGNIFICANTLY WARMER TEMPERATURES INDICATED FOR THE WEEKEND.
AS A RESULT LOW CONFIDENCE AT THIS TIME FOR THIS PORTION OF THE
EXTENDED PERIOD.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
MAIN AVIATION CONCERN WILL BE STRONG THUNDERSTORMS THAT DEVELOP
AFTER 22Z AND PERSIST INTO THE EVENING. LARGE HAIL AND SEVERE
DOWNBURST WINDS WILL BE POSSIBLE WITH A FEW OF THESE STORMS.
STORMS SHOULD WEAKEN AFTER 03Z...AND MAY DIMINISH TO SHOWERS OR
WEAK CONVECTION BY 06Z THEN END SHORTLY AFTER 06Z. A WELL-DEFINED
COLD FRONT EXTENDED FROM AROUND KOFK TO KGRI AT 17Z AND THIS FRONT
WILL SLOWLY MOVE THROUGH EASTERN NEBRASKA TODAY AND
TONIGHT...SWITCHING THE WINDS FROM SOUTH TO NORTHWEST. AHEAD OF
THE FRONT DURING THE AFTERNOON HOURS...KOMA AND KLNK WILL HAVE
SOUTH WINDS GUSTING OVER 20 KNOTS...BUT THESE SHOULD WEAKEN BY
SUNSET AS THE FRONT APPROACHES.
AFTER THE STORMS AND SHOWERS MOVE OUT LATE TONIGHT...VFR
CONDITIONS ARE EXPECTED FROM THE EARLY MORNING HOURS SUNDAY
THROUGH THE END OF THE TAF PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/NIETFELD
000
FXUS63 KGID 191926
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
226 PM CDT SAT MAY 19 2012
.SHORT TERM...REST OF TODAY THROUGH SUNDAY. PRIMARY FORECAST
CONCERN LIES WITH THUNDERSTORM CHANCES THROUGH THIS EVENING.
UPPER LEVEL PROFILER AND SATELLITE DATA NOT SHOWING ANY SURPRISES
EARLY THIS AFTERNOON...WITH THE SYSTEM OF INTEREST STARTING TO
PUSH OUT OF CO AND ONTO THE PLAINS...AND ACTIVITY IS ALREADY
ONGOING ACROSS PORTIONS OF SWRN NEB/WRN KS AND MOVING TOWARD THE
WRN EDGE OF THE CWA. AT THE SFC...MAIN FRONT MADE PRETTY GOOD
EASTWARD PROGRESS THIS MORNING...MAKING IT ABOUT HALFWAY THROUGH
THE CWA...WHERE IT HAS SINCE SLOWED/STALLED OUT. WARMER MID LEVEL
TEMPS HAVE KEPT THE AREA IN THE PROXIMITY OF THE FRONT CAPPED OFF
SO FAR...BUT THAT ISNT EXPECTED TO LAST TOO MUCH LONGER AS THE
UPPER LEVEL TROUGH APPROACHES. EVEN WITH PLENTY OF CLOUD COVER IN
PLACE...TEMPS CLIMBING WELL INTO THE 70S AND LOWER 80S ALONG WITH
DEWPOINTS APPROACHING/AT 60 DEGREES HAS RESULTED IN INSTABILITY
VALUES NEAR/+ 2000 J/KG ALONG AND AHEAD OF THE FRONT WITH WEAKER
SHEAR...WITH LESS INSTABILITY BUT BETTER SHEAR SET UP BEHIND THE
FRONT.
THIS SURFACE FRONT WILL REMAIN THE PRIMARY FOCUS FOR CONVECTIVE
DEVELOPMENT THIS AFTERNOON/EVENING...BUT WILL ALSO HAVE TO KEEP AN
EYE ON THE ONGOING ELEVATED ACTIVITY TO THE WEST. SHORT TERM/HIRES
MODELS REMAIN IN GOOD AGREEMENT SHOWING THE E/SE HALF OF THE CWA
BEING PRIMARILY IMPACTED BY ANY ACTIVITY ASSOCIATED WITH THE
FRONT...WHERE HAIL/WIND AND AN ISO TOR WILL REMAIN A CONCERN.
HAIL/WIND WOULD BE THE CONCERNS WITH THE ACTIVITY FURTHER WEST.
PRECIPITATION IS EXPECTED SHIFT OFF TO THE E/NE...AND SHIFT OUT
OF THE CWA NEAR/IF NOT BEFORE MIDNIGHT.
ONCE WE GET PAST MIDNIGHT TONIGHT AND THROUGH TOMORROW...DRY
FORECAST REMAINS IN PLACE...WITH SLIGHT NORTHWESTERLY FLOW SETTING
UP IN THE UPPER LEVELS BEHIND THIS LATEST TROUGH AXIS AND AHEAD OF
WEAK RIDGING DEVELOPING OVER THE ROCKIES. ONCE THE SFC FRONT
PUSHES OUT OF THE CWA...HIGH PRESSURE SETTLES IN FROM THE
WEST...AND IS EXPECTED TO BE CENTERED OVER THE CENTRAL PLAINS
THROUGH THE DAY. THIS WILL KEEP WINDS GENERALLY NORTHERLY...WITH
SPEEDS ARND 10 MPH...AND WITH COOLER AIR ACCOMPANYING THIS SFC
HIGH...TEMPERATURES ARE EXPECTED TO `ONLY` TOP OUT IN THE LOW/MID
70S...OR NEAR AVERAGE FOR THIS TIME OF YEAR.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
FOR SUNDAY THROUGH TUESDAY NIGHT...UPPER LEVEL RIDGING SHOULD BE A
STRONG INFLUENCE ON KEEP OUR WEATHER DRY WITH A SURFACE TROUGH
IN THE LEE OF THE ROCKY MOUNTAINS DEVELOPING DURING THIS PERIOD.
TUESDAY MAY VERY WELL BE THE WARMEST DAY WITH 850 MB BEING THE
WARMEST AHEAD OF LEE TROUGH AND AN APPROACHING COLD FRONT.
ALSO...TUESDAY AFTERNOON WILL BE QUITE WINDY WITH AN INCREASING
PRESSURE GRADIENT...ESPECIALLY WEST OF HIGHWAY 281.
THE UPPER LEVEL PATTERN BECOMES QUITE AMPLIFIED BY WEDNESDAY.
MODELS ARE IN GOOD AGREEMENT THAT A MEAN LONGWAVE TROUGH
DEVELOPS IN THE WESTERN UNITED STATES AND A LONGWAVE RIDGE TO THE
EAST. THE GFS IS MORE EARLY AND AGGRESSIVE THAN THE ECMWF AT
EJECTING PIECES OF ENERGY INTO THE PLAINS...WHICH WILL LEAD TO AT
LEAST LOW CHANCES OF PRECIPITATION FROM WEDNESDAY INTO THE REST OF
THE LONG TERM FORECAST. AT THE SURFACE...A WARM FRONT IS FORECAST
TO PASS EAST OF THE CWA BY SOMETIME WEDNESDAY...WITH A COLD FRONT
IN WESTERN NEBRASKA PREDICTED TO STALL SOMEWHERE JUST WEST OF THE
CWA. THE RIDGE TO THE EAST OF THE CWA SHOULD SHUNT MOISTURE RETURN
TO AT LEAST SOME EXTENT...CALLING INTO QUESTION THE CHANCES OF
SEVERE WEATHER AND FOR THAT MATTER...PRECIPITATION. MOISTURE
SHOULD EVENTUALLY MAKE A RETURN WITH THE STALLED BOUNDARY HANGING
AROUND THE REGION INTO THE WEEKEND. DETERMINING SEVERE CHANCES
WILL BE DICEY...BUT STORMS WEDNESDAY AFTERNOON AND EVENING COULD
BE STRONG TO SEVERE...ESPECIALLY AS THE LOW-LEVEL JET KICKS IN
WEDNESDAY EVENING. THE PLACEMENT OF THE BAROCLINIC ZONE WILL BE
CRUCIAL IN DETERMINING SEVERE WEATHER CHANCES FURTHER OUT THAN
WEDNESDAY. SHEAR NEAR THE BOUNDARY SHOULD BE AMPLE FOR SEVERE
WEATHER...BUT INSTABILITY SEEMS TO BE THE LIMITING FACTOR HERE.
NORTHERN AND WESTERN AREAS OF THE CWA HAVE POTENTIAL TO BE COOLER
THAN THE REST IF THE BOUNDARY DRAPES INTO OUR CWA.
&&
.AVIATION...18Z TAF. PRIMARY CONCERN FOR THIS TAF PERIOD LIES WITH
THUNDERSTORM CHANCES. AN UPPER LEVEL STORM SYSTEM PUSHING OUT OF
THE ROCKIES WILL BRING INCREASING THUNDERSTORM CHANCES TO THE
TERMINAL AREA THIS AFTERNOON AND INTO THE EARLY EVENING...AND HAVE
VC MENTION AS WELL AS A TEMPO GROUP MENTIONED. THE SURFACE COLD
FRONT HAS PUSHED SOUTH OF THE TERMINAL...WINDS WILL BE GUSTY THIS
AFTERNOON...AND WILL REMAIN NORTH/NORTHWESTERLY THROUGH THIS TAF
PERIOD. OUTSIDE OF MVFR CIGS BEING POSSIBLE THIS AFTERNOON/EVENING
AS THE STORM SYSTEM PASSES...VFR CONDITIONS EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
000
FXUS63 KLBF 191747
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1247 PM CDT SAT MAY 19 2012
.AVIATION...AN UPPER LEVEL DISTURBANCE WILL MOVE NORTHEAST ACROSS
THE AREA THIS AFTERNOON AND EVENING. SHOWERS AND THUNDERSTORMS
WILL ACCOMPANY THIS DISTURBANCE...AND MOSTLY IMPACT AREAS ALONG
AND SOUTH OF A LINE FROM KANW TO KSNY. EXPECTING THUNDERSTORMS TO
MOVE THROUGH THE KLBF TERMINAL AROUND 20Z WITH SOME LINGERING
LIGHT RAIN AFTERWARD...TILL AROUND 00Z. AT THIS TIME...EXPECTING
MOST OF THE ACTIVITY TO STAY SOUTH AND EAST OF THE KVTN TAF SITE.
OUTSIDE OF PRECIPITATION...WIDESPREAD MVFR CEILINGS CAN BE
EXPECTED DUE TO STRATUS. SFC WINDS WILL BE NORTH AT 15 TO 25 KTS.
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT SAT MAY 19 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST FOCUS THROUGH THIS PERIOD IS ON PRECIPITATION CHANCES AND
WINDS TODAY AND TONIGHT...THEN WITH TEMPERATURES THROUGH THE PERIOD.
AS OF 08Z...WATER VAPOR IMAGERY SHOWED RIDGING OVER THE GREAT
LAKES AND EASTERN CONUS WITH TROUGHING ACROSS THE INTER-MOUNTAIN
WEST. THIS TROUGH WAS CHARACTERIZED BY TWO MAIN PV ANOMALIES...ONE
OVER ALBERTA INTO MONTANA AND THE OTHER OVER THE FOUR CORNERS. IN
ADDITION...A LEAD WEAK WAVE HAD PUSHED ACROSS NEBRASKA EARLIER ON
FRIDAY EVENING...WHICH HAD HELPED FIRE THE CONVECTION THAT OCCURRED.
THE COLD FRONT HAD PASSED THROUGH MUCH OF THE FORECAST AREA AS OF
08Z AS IT WAS LOCATED FROM NORTHEAST SOUTH DAKOTA INTO WESTERN
KANSAS...ROUGHLY FROM KP67 IN NORTH DAKOTA TO KONL TO KMCK IN
NEBRASKA AND SOUTHWEST TO KSPD IN SOUTHEAST COLORADO. CONVECTION
HAD FOR THE MOST PART MOVED OUT OF THE FORECAST AREA...LEAVING
MANY OUTFLOW BOUNDARIES ACROSS THE REGION WHICH HAS IMPACTED WINDS
OVERNIGHT. TEMPERATURES HAD BEEN SLOWLY FALLING OVERNIGHT AS THE
FRONT MOVED SOUTHEAST...HOWEVER LOCATIONS AHEAD OF THE FRONT
REMAIN IN THE 70S.
THE FRONT WON/T SEE MUCH MOVEMENT UNTIL AFTER 20.00Z WHEN THE
UPPER LEVEL SHORTWAVE TROUGH PUSHES ACROSS NEBRASKA INTO MINNESOTA
AND IOWA TONIGHT...WHICH WILL PUSH THE WHOLE SYSTEM EAST. THIS
WILL LEAD TO A DRASTIC DIFFERENCE IN WEATHER ACROSS THE EASTERN
AND WESTERN PARTS OF THE STATE OF NEBRASKA. ALTHOUGH MUCH OF THE
LOCAL AREA WILL BE BEHIND THE FRONT...THE FAR EASTERN AREAS...EAST
OF A KMCK TO KBBW TO KONL WILL STAY GENERALLY IN THE VICINITY OF
THE FRONT...SO MAY EXPERIENCE A MUCH DIFFERENT DAY.
TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN HAS BEEN
EXPERIENCED THE PAST SEVERAL DAYS DUE TO STRONG COLD AIR ADVECTION
BEHIND THE COLD FRONT. FOR EXAMPLE...IN THE 19.00Z SOUNDING FROM
LBF...THE 850MB TEMPERATURE WAS 25C AND BY 20.00Z...MODELS ARE
PROJECTING THE 850MB TEMPERATURE AT THE SAME LOCATION TO HAVE
DROPPED TO AROUND 9C. ALSO HELPING TO KEEP TEMPERATURES DOWN TODAY
WILL BE PLENTIFUL CLOUD COVER. THERE IS GOOD CONSISTENCY BETWEEN
THE MODELS OF A STRATUS DECK FILLING IN THIS MORNING ACROSS MUCH
OF WESTERN NEBRASKA...WHICH WILL STICK AROUND THROUGH THE MAJORITY
OF THE DAY. ALSO...WITH THE INCREASED MOISTURE AND EXTRA UPWARD
MOTION FROM THE PASSAGE OF THE UPPER LEVEL SYSTEM SHOULD SEE
PRECIPITATION THROUGH THE DAY. DO EXPECT MOST OF THIS
PRECIPITATION TO BE FAIRLY LIGHT THIS MORNING...MAYBE EVEN JUST
DRIZZLE AT TIMES. LOOKING FOR INCREASED PRECIPITATION AND
THUNDERSTORM CHANCES IN THE AFTERNOON...ESPECIALLY ALONG AND NEAR
THE COLD FRONT. ALTHOUGH MOST OF THIS ACTIVITY WILL BE EAST OF THE
AREA...COULD SEE A FEW ISOLATED THUNDERSTORMS BACK INTO CENTRAL
AND WESTERN NEBRASKA AS MODELS INDICATE A FEW HUNDRED J/KG OF CAPE
WILL REMAIN ACROSS MUCH OF THE AREA...AS WELL AS THE . AS THE
WHOLE SYSTEM MOVES NORTHEAST THIS EVENING...WILL LIKELY CONTINUE
TO SEE SOME LIGHT RAIN OVER NORTH CENTRAL NEBRASKA WITH
FRONTOGENESIS ONGOING ON THE BACKSIDE OF THE SYSTEM. THEN
EXPECTING THE RAIN TO BE OUT OF THE AREA BY MIDNIGHT.
ALSO BEHIND THE FRONT...A TIGHT PRESSURE GRADIENT WILL KEEP WINDS
STRONG OUT OF THE NORTH AND NORTHWEST TODAY ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEBRASKA. ALTHOUGH STRONG COLD AIR
ADVECTION WILL BE ONGOING...THE AREA WILL NOT BE IN AN AREA OF
SUBSIDENCE AS THE FOUR CORNERS SHORTWAVE APPROACHES. THIS ALONG
WITH STRATUS DECK KEEPING THE MIXED LAYER QUITE SHALLOW SO DON/T
BELIEVE WINDS WILL REACH ADVISORY CRITERIA.
WEATHER WILL BE QUIET THEN FOR SUNDAY THROUGH MONDAY. HIGH
PRESSURE SETTLES IN SUNDAY WITH LIGHT WINDS AND MOSTLY SUNNY
SKIES. TEMPERATURES WILL SEE SOME RECOVERY SUNDAY...BUT WILL BE
IN THE UPPER 60S AND LOW 70S. THE COOLEST LOCATIONS WILL BE OVER
NORTH CENTRAL NEBRASKA WHERE TEMPERATURES ALOFT WILL SEE LITTLE
WARMING. RIDGING ALOFT WILL AGAIN BE INFLUENCING THE REGION FOR
THE FIRST PART OF THE WORK WEEK AND WITH SOUTHERLY FLOW AT THE
SURFACE...TEMPERATURES WILL WARM AND MOISTURE WILL SEE A SLOW
INCREASE AS THE GULF OPENS UP. LOOKING FOR HIGHS MONDAY IN THE 70S
AND LOW 80S WITH BREEZY SOUTHERLY WINDS.
LONG TERM...TUESDAY THROUGH FRIDAY
AS WAS STATED ABOVE...THERE ARE INDICATIONS THAT THE GULF WILL
START TO OPEN UP IN THE TUESDAY WEDNESDAY TIME-FRAME ALLOWING
MOISTURE TO BE PULLED INTO THE FORECAST AREA THROUGH THE REMAINDER
OF THE WEEK. IN TURN...TROUGHING MOVES INTO THE PACIFIC
NORTHWEST...KEEPING RIDGING OVER THE FORECAST AREA. THERE ARE
PLENTY OF DIFFERENCES IN MODEL SOLUTIONS WEDNESDAY AND
BEYOND...HOWEVER GENERAL CONSENSUS IS TROUGHING OVER THE PACIFIC
NORTHWEST WITH SEVERAL SYSTEMS PUSHING OVER THE RIDGE...MAINLY
AFFECTING THE DAKOTAS AND NORTHERN NEBRASKA. THE ECMWF SETTLES THE
UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST...AND THEN EJECTS SEVERAL
WEAKER SHORTWAVES OUT OF THE TROUGH AND PUSHING OVER THE RIDGE.
THIS WILL KEEP A LOT OF THE SHOWERS AND THUNDERSTORMS OVER THE
DAKOTAS AND THE NORTHERN PARTS OF NEBRASKA. THE GFS ON THE OTHER
HAND MOVES THE WHOLE SYSTEM ACROSS THE NORTHERN CONUS THROUGH THE
SECOND HALF OF THE WEEK. THIS SOLUTION WOULD PUSH A FRONT ACROSS
THE FORECAST AREA AND IN TURN BRING HIGHER RAIN CHANCES. REALLY
DIDN/T LOCK ONTO ANY ONE SOLUTION YET SO WILL JUST KEEP SLIGHT AND
CHANCE PRECIPITATION CHANCES IN THE FORECAST FOR THE OUTER
PERIODS. AS FOR TEMPERATURES THOUGH...LOOKING LIKE A WARM PERIOD
WITH TEMPERATURES ABOVE NORMAL IN THE UPPER 70S AND 80S...WITH
POSSIBLY 90S ON TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...TAYLOR
000
FXUS63 KOAX 191738
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1238 PM CDT SAT MAY 19 2012
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
MAIN AVIATION CONCERN WILL BE STRONG THUNDERSTORMS THAT DEVELOP
AFTER 22Z AND PERSIST INTO THE EVENING. LARGE HAIL AND SEVERE
DOWNBURST WINDS WILL BE POSSIBLE WITH A FEW OF THESE STORMS.
STORMS SHOULD WEAKEN AFTER 03Z...AND MAY DIMINISH TO SHOWERS OR
WEAK CONVECTION BY 06Z THEN END SHORTLY AFTER 06Z. A WELL-DEFINED
COLD FRONT EXTENDED FROM AROUND KOFK TO KGRI AT 17Z AND THIS FRONT
WILL SLOWLY MOVE THROUGH EASTERN NEBRASKA TODAY AND
TONIGHT...SWITCHING THE WINDS FROM SOUTH TO NORTHWEST. AHEAD OF
THE FRONT DURING THE AFTERNOON HOURS...KOMA AND KLNK WILL HAVE
SOUTH WINDS GUSTING OVER 20 KNOTS...BUT THESE SHOULD WEAKEN BY
SUNSET AS THE FRONT APPROACHES.
AFTER THE STORMS AND SHOWERS MOVE OUT LATE TONIGHT...VFR
CONDITIONS ARE EXPECTED FROM THE EARLY MORNING HOURS SUNDAY
THROUGH THE END OF THE TAF PERIOD.
NIETFELD
&&
.PREV DISCUSSION... /ISSUED 315 AM CDT SAT MAY 19 2012/
DISCUSSION...
THUNDERSTORM POTENTIAL THROUGH TONIGHT IS THE MAIN FORECAST CONCERN.
SOME SEVERE STORMS APPEAR POSSIBLE ALONG WITH LOCALLY HEAVY RAIN
MAINLY FROM LATE AFTERNOON THROUGH THE EVENING.
500 MB CHART FROM LAST EVENING SHOWED A TROUGH OVER THE ROCKIES AND
STARTING TO MOVE OUT INTO THE HIGH PLAINS. 12 HOUR HEIGHT FALLS WERE
NOT ALL THAT IMPRESSIVE...WITH A MAX OF 40 METERS AT GRAND JUNCTION.
MOISTURE AT 850 MB WAS STILL MEAGER...BUT VALUES UP TO AROUND 10
DEGREES CELSIUS WERE NOTED FROM PARTS OF TEXAS INTO SOUTHWESTERN
OKLAHOMA.
A COLD FRONT WILL CONTINUE TO PRESS EASTWARD ACROSS THE FORECAST
AREA THROUGH TONIGHT. HIGHS THIS AFTERNOON SHOULD BE MAINLY IN THE
80S...WITH MID OR UPPER 70S MORE LIKELY IN OUR FAR WESTERN ZONES.
ALTHOUGH SOME STORMS ARE POSSIBLE THROUGH THE MORNING AND INTO
EARLY AFTERNOON...IT APPEARS MAIN SEVERE RISK IS 4 PM TO 10 PM.
0 TO 6 KILOMETER BULK SHEAR VALUES ARE EXPECTED TO BE 30 TO 50
KNOTS...MORE THAN ADEQUATE FOR ORGANIZED STORMS.
FRONT WILL CONTINUE TO MOVE EASTWARD TONIGHT...WITH PRECIPITATION
CHANCES GENERALLY DECREASING AS THE NIGHT PROGRESSES. KEPT A SMALL
POP SUNDAY MORNING FOR PARTS OF THE AREA AS SOME SHOWERS MAY LINGER.
SUNDAY WILL BE NOTICEABLY COOLER WITH A NORTH BREEZE...AND EXPECT
MOST READINGS TO TOP OUT IN THE 70S.
EXPECT THE PERIOD FROM MONDAY THROUGH TUESDAY TO BE DRY...AND
HAVE TEMPERATURES SLOWLY MODERATING THROUGH MID WEEK. MID
TROPOSPHERIC RIDGE WILL BUILD OVER THE ROCKIES AND OUT INTO THE
PLAINS MONDAY/TUESDAY AS A TROUGH DIGS IN OVER THE WESTERN PART OF
THE NATION. THIS TURNS OUR MID LEVEL FLOW TO SOUTHWEST BY TUESDAY
NIGHT. HELD OFF A BIT ON RAIN CHANCES UNTIL WEDNESDAY...BUT WILL
NEED TO MONITOR LATER FORECASTS. MIGHT NEED TO ADD A CHANCE OF
THUNDERSTORMS TUESDAY NIGHT AS 850 MB MOISTURE RETURNS WITH LOW
LEVEL JET.
OTHERWISE MODELS AGREE ON GENERAL POTENTIALLY ACTIVE PATTERN FOR THE
MID AND LATTER PART OF THE WEEK...BUT DIFFER IN REGARDS TO DETAILS.
DID NOT HAVE A STRONG MODEL PREFERENCE AT THIS TIME.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KGID 191726
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1226 PM CDT SAT MAY 19 2012
.AVIATION...18Z TAF. PRIMARY CONCERN FOR THIS TAF PERIOD LIES WITH
THUNDERSTORM CHANCES. AN UPPER LEVEL STORM SYSTEM PUSHING OUT OF
THE ROCKIES WILL BRING INCREASING THUNDERSTORM CHANCES TO THE
TERMINAL AREA THIS AFTERNOON AND INTO THE EARLY EVENING...AND HAVE
VC MENTION AS WELL AS A TEMPO GROUP MENTIONED. THE SURFACE COLD
FRONT HAS PUSHED SOUTH OF THE TERMINAL...WINDS WILL BE GUSTY THIS
AFTERNOON...AND WILL REMAIN NORTH/NORTHWESTERLY THROUGH THIS TAF
PERIOD. OUTSIDE OF MVFR CIGS BEING POSSIBLE THIS AFTERNOON/EVENING
AS THE STORM SYSTEM PASSES...VFR CONDITIONS EXPECTED.
&&
PREV DISCUSSION... /ISSUED 341 AM CDT SAT MAY 19 2012/
SHORT TERM...THROUGH 12Z TUESDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES TROUGHING OVER THE WESTERN CONUS...WITH RIDGING OVER THE
EAST. A 850MB JET STREAK OF AROUND 50KTS IS NOTED OVER THE CENTRAL
PLAINS...WITH MID AND UPPER LEVEL JET ENERGY REMAINING TO OUR
WEST...EXTENDING FROM THE SOUTHWESTERN CONUS INTO THE ROCKY
MOUNTAIN RANGE. WATER VAPOR IMAGERY SHOW A MID LEVEL SHORT WAVE AT
THE BASE OF THE WESTERN CONUS LONG WAVE TROUGH CURRENTLY OVER THE
FOUR CORNERS REGION. WATER VAPOR IMAGERY ALSO SHOWS INCREASED
VALUES OF MID LEVEL MOISTURE MOVING IN FROM THE PACIFIC INTO WEST
TEXAS AND THEN NORTH/NORTHEASTWARD INTO THE CENTRAL PLAINS. A MID
LEVEL DRY INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS
REGION NORTHEASTWARD INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE
AN AREA OF LOW PRESSURE IS NOTED OVER NORTHWESTERN KANSAS. A
WARM FRONT EXTENDS NORTHEASTWARD FROM THE LOW INTO NORTH CENTRAL
NEBRASKA AND SOUTH CENTRAL SOUTH DAKOTA...A COLD FRONT EXTENDS
WEST/SOUTHWEST FROM THE LOW INTO COLORADO...AND A DRY LINE
EXTENDS SOUTH FROM THE LOW ALONG THE COLORADO/KANSAS BORDER. THE
LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE SOUTH AS A
RESULT.
MODEL CONSENSUS CONTINUES TO SUGGEST THE MID LEVEL SHORT
WAVE...CURRENTLY OVER THE FOUR CORNERS REGION...WILL MOVE NORTHEAST
TODAY WITH A NEGATIVELY-TILTED TROUGH AXIS EXPECTED TO PUSH OVER
OUR AREA THIS AFTERNOON AND EVENING. THE SURFACE LOW...CURRENTLY
OVER NORTHWESTERN KANSAS...IS ALSO EXPECTED TO MOVE NORTHEAST THUS
ALLOWING THE LOW LEVEL BAROCLINIC ZONE TO PUSH ACROSS OUR AREA
THROUGH THE DAY. QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC
AND SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM THE 4KM
WRF-NMM...ALL SUGGEST DEEP SURFACE-BASED CONVECTION WILL BE
REALIZED ALONG AND AHEAD OF THE LOW LEVEL BAROCLINIC ZONE BY
MID-AFTERNOON...MOST LIKELY SOMEWHERE OVER THE EASTERN HALF OF
OUR CWA. SOUTHERLY LOW LEVEL FLOW IS CONTINUING TO PROMOTE
IMPRESSIVE LOW LEVEL MOISTURE FLUX INTO OUR AREA THIS
MORNING...WITH SURFACE DEW POINTS JUMPING ALMOST 10 DEGREES
THROUGH THE PAST 9 HOURS ACROSS THE EASTERN HALF OF THE CWA AND
NOW WELL INTO THE 50S AND APPROACHING THE 60S AS OF 08Z. THESE
INCREASING VALUES OF LOW LEVEL MOISTURE WILL HELP PROMOTE 0-1KM
MLCAPE VALUES OF 2000-2500J/KG ACROSS THE EASTERN HALF OF OUR CWA
BY MID-AFTERNOON. IN ADDITION TO THESE INCREASING VALUES OF
INSTABILITY...THE EMERGENCE OF A ~50KT 500MB JET STREAK WILL ALSO
HELP INCREASE DEEP-LAYER BULK SHEAR TO AROUND 40KTS...THUS MAKING
SUPER CELL DEVELOPMENT POSSIBLE AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE WHERE DISCRETE THUNDERSTORM DEVELOPMENT IS MORE LIKELY. BACK
ALONG THE LOW LEVEL BAROCLINIC ZONE...THE UNIDIRECTIONAL WIND
FIELD THROUGH MUCH OF THE TROPOSPHERE SUGGESTS A QUASI-LINEAR
CONVECTIVE SYSTEM WILL PRESENT ITSELF AS DEEP CONVECTION BECOMES
REALIZED...THUS PROVIDING MORE OF A WIND THREAT THAN ANYTHING
ELSE. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF SEVERE WEATHER
FOR THIS AFTERNOON AND EVENING. LATEST MODEL GUIDANCE DOES SUGGEST THE
LOW LEVEL BAROCLINIC ZONE WILL BE SOMEWHAT SLOWER THAN WHAT WAS
BEING INDICATED 24-48 HOURS AGO AND AS A RESULT...WILL GO AHEAD
EXPAND THE AREA OF POSSIBLE SEVERE WEATHER ACROSS OUR CWA...WHICH
WILL NOW INCLUDE AREAS ALONG AND EAST OF A LINE FROM SPALDING...TO
GRAND ISLAND...TO NATOMA WHICH IS WHERE THE SURFACE FRONT IS
CURRENTLY EXPECTED TO BE POSITIONED AT 21Z. WILL CONTINUE THE HAIL
AND WIND THREAT FOR THE REASONS MENTIONED ABOVE. 0-1KM HELICITY
DOES NOT APPEAR OVERLY IMPRESSIVE PER THE NAM...OPERATIONAL GFS
AND EC...GENERALLY AROUND 100M^2/S^2 ACROSS OUR SOUTHEAST AND
LESSER VALUES FARTHER NORTHWEST. THAT BEING SAID...FORECAST
PROXIMITY SOUNDINGS FROM THE NAM FOR LOCATIONS IMMEDIATELY AHEAD
OF THE LOW LEVEL BAROCLINIC ZONE...WHERE THE SURFACE WIND FIELD
WILL BE LOCALLY BACKED...DOES PRESENT A CLASSIC VEERING LOW LEVEL
WIND PROFILE THUS RESULTING IN AN AREA OF LOCALLY ENHANCED LOW
LEVEL HELICITY. THUS...ITS HARD TO COMPLETELY WRITE OFF THE THREAT
FOR TORNADOES...ESPECIALLY IF A DISCRETE SUPER CELL CAN BE
REALIZED IMMEDIATELY AHEAD OF THE LOW LEVEL BAROCLINIC ZONE. ALL
THAT BEING SAID...WILL GO AHEAD AND ALSO INCLUDE A TORNADO MENTION
IN THE HWO. SEVERE CONVECTION SHOULD PUSH EAST OF OUR AREA THIS
EVENING AS THE LOW LEVEL BAROCLINIC ZONE ALSO CLEARS OUR AREA TO
THE EAST. MID LEVEL DEFORMATION TO THE NORTHWEST OF THE MID LEVEL
SHORT WAVE WILL LIKELY PROMOTE FURTHER PRECIPITATION ACROSS
NORTHERN PORTIONS OF THE CWA THROUGH 06Z...WITH PRECIPITATION
ENDING ALTOGETHER THEREAFTER AS THE MID LEVEL SHORT WAVE PUSHES
OFF TO THE EAST. AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PRESENT DRY CONDITIONS TO THE AREA THROUGH THE REMAINDER OF THE
SHORT TERM FORECAST PERIOD.
TODAY REMAINS A TRICKY TEMPERATURE FORECAST WITH TEMPERATURES
REMAINING HIGHLY DEPENDENT UPON THE POSITION OF THE LOW LEVEL
BAROCLINIC ZONE...AS WELL AS CLOUD COVER AND PRECIPITATION.
PREVIOUS SHIFTS OPTED TO RAISE TEMPERATURES SOMEWHAT ACROSS OUR
EAST/SOUTHEAST AND GIVEN THE NOW SLOWER EXPECTED PROGRESSION OF
THE LOW LEVEL BAROCLINIC ZONE...THIS APPEARS TO BE GREAT DECISION.
THAT BEING SAID...AM BECOMING INCREASINGLY CONCERNED THAT
TEMPERATURES ACROSS OUR NORTH/NORTHWEST COULD STRUGGLE MIGHTILY AS
THE LOW LEVEL BAROCLINIC ZONE CLEARS DURING THE 12Z-15Z
TIME FRAME...AND CLOUD COVER AND PRECIPITATION OVERTAKE THE AREA.
ATYPICAL DIURNALS WILL LIKELY BE OBSERVED ACROSS OUR
NORTH/NORTHWEST WITH DAYTIME TEMPERATURES NOT LIKELY CLIMBING MORE
THAN 10 DEGREES ABOVE EARLY MORNING TEMPERATURES. WENT AHEAD AND
DECREASED TODAYS HIGHS ACROSS OUR NORTH/NORTHWEST A FEW DEGREES TO
GET THEM INTO THE LOW TO MID 70S. LOCATIONS FARTHER SOUTHEAST WILL
LIKELY SEE MUCH WARMER WEATHER AS THEY REMAIN PRE-FRONTAL LONGER
AND THE INFILTRATION OF A MID LEVEL DRY INTRUSION ALLOWS FOR MORE
SUNSHINE BEFORE DEEP CONVECTION INITIALIZES DURING THE AFTERNOON.
LOW TO MID 80S WILL LIKELY BE NOTED ACROSS THE SOUTHEASTERN HALF
OF OUR CWA AS A RESULT. THE INTRUSION OF A SURFACE RIDGE WILL THEN
PRESENT COOLER CONDITIONS CWA-WIDE SUNDAY AND MONDAY...WITH
AFTERNOON HIGHS LIKELY REMAINING IN THE 70S FOR THE MOST PART.
LONG TERM...TUESDAY THROUGH FRIDAY. MAIN FORECAST CONCERN WILL BE
CHANCES FOR THUNDERSTORMS WEDNESDAY THROUGH FRIDAY.
TUESDAY AND TUESDAY NIGHT AN UPPER LEVEL RIDGE MOVES THROUGH THE
AREA AND EXPECT WARM TEMPERATURES. THE PRESSURE GRADIENT TIGHTENS
DURING THE DAY AND SOUTH WINDS SHOULD INCREASE DURING THE DAY.
TUESDAY NIGHT A COLD FRONT APPROACHES THE AREA. THIS FRONT MOVES
INTO THE FORECAST AREA ON WEDNESDAY. AS AN UPPER LEVEL WAVE MOVES
INTO THE AREA AREA THE CHANCE OF THUNDERSTORMS INCREASES. BY
WEDNESDAY NIGHT THE FRONT STALLS OUT IN THE SOUTHEAST PART OF THE
AREA AND THUNDERSTORMS DEVELOP ALONG THE FRONT. THERE IS 2500 TO
3000 J/KG CAPE DURING THE AFTERNOON AND EVENING AND THERE COULD BE
SOME STRONGER THUNDERSTORMS POSSIBLE. THE UPPER WAVE MOVES THROUGH
THE AREA ON THURSDAY AND THE THUNDERSTORM CHANCES DIMINISH.
A SECONDARY WAVE MOVES THROUGH THURSDAY NIGHT INTO FRIDAY AND THERE
IS ANOTHER SURFACE LOW THAT DEVELOPS IN KANSAS WITH A CHANCE FOR
THUNDERSTORMS TO THE NORTH OF THE FRONT THURSDAY NIGHT. ON FRIDAY
THE WAVE MOVES OUT AND THUNDERSTORMS COME TO AN END.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
SHORT...BRYANT
LONG...JCB
000
FXUS63 KLBF 191133
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
633 AM CDT SAT MAY 19 2012
.AVIATION...
FOR THE KVTN AND KLBF TERMINALS THROUGH 12Z SUNDAY.
EXPECT OVERCAST SKIES TODAY AND THIS EVENING WITH MVFR CIGS LIKELY
AT THE KLBF TERMINAL TODAY WITH CIGS DOWN TO 2000 FT AGL. LIGHT RAIN
IS EXPECTED TO DEVELOP THIS AFTERNOON AS AN UPPER LEVEL TROUGH OF
LOW PRESSURE TRACKS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. LOOK
FOR CIGS TO BEGIN TO RISE ABOVE 6000 FT AGL THIS EVENING WITH CLEARING
SKIES EXPECTED AFTER 06Z TONIGHT. EXPECT NORTHERLY WINDS OF 15 TO 25
KTS WITH FREQUENT GUSTS TO 30 KTS TODAY. WINDS WILL DIMINISH TO
AROUND 10 KTS THIS EVENING.
FOR THE KVTN TERMINAL...MVFR SKIES ARE EXPECTED TODAY WITH CIGS AON
1500 FT AGL. LIGHT RAIN SHOWERS ARE POSSIBLE...MAINLY AFTER
16Z...PERSISTING THROUGH MID EVENING. SCATTERED TO BROKEN CLOUDINESS
IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS BEFORE CLEARING
AROUND 12Z SUNDAY. WINDS TODAY WILL BE FROM THE NORTH NORTHWEST AT
15 TO 25 KTS WITH SOME PERIODIC GUSTS TO 30 KTS. WINDS WILL DIMINISH
TO AROUND 10 KTS AFTER SUNSET THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 401 AM CDT SAT MAY 19 2012/
SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST FOCUS THROUGH THIS PERIOD IS ON PRECIPITATION CHANCES AND
WINDS TODAY AND TONIGHT...THEN WITH TEMPERATURES THROUGH THE PERIOD.
AS OF 08Z...WATER VAPOR IMAGERY SHOWED RIDGING OVER THE GREAT
LAKES AND EASTERN CONUS WITH TROUGHING ACROSS THE INTER-MOUNTAIN
WEST. THIS TROUGH WAS CHARACTERIZED BY TWO MAIN PV ANOMALIES...ONE
OVER ALBERTA INTO MONTANA AND THE OTHER OVER THE FOUR CORNERS. IN
ADDITION...A LEAD WEAK WAVE HAD PUSHED ACROSS NEBRASKA EARLIER ON
FRIDAY EVENING...WHICH HAD HELPED FIRE THE CONVECTION THAT OCCURRED.
THE COLD FRONT HAD PASSED THROUGH MUCH OF THE FORECAST AREA AS OF
08Z AS IT WAS LOCATED FROM NORTHEAST SOUTH DAKOTA INTO WESTERN
KANSAS...ROUGHLY FROM KP67 IN NORTH DAKOTA TO KONL TO KMCK IN
NEBRASKA AND SOUTHWEST TO KSPD IN SOUTHEAST COLORADO. CONVECTION
HAD FOR THE MOST PART MOVED OUT OF THE FORECAST AREA...LEAVING
MANY OUTFLOW BOUNDARIES ACROSS THE REGION WHICH HAS IMPACTED WINDS
OVERNIGHT. TEMPERATURES HAD BEEN SLOWLY FALLING OVERNIGHT AS THE
FRONT MOVED SOUTHEAST...HOWEVER LOCATIONS AHEAD OF THE FRONT
REMAIN IN THE 70S.
THE FRONT WON/T SEE MUCH MOVEMENT UNTIL AFTER 20.00Z WHEN THE
UPPER LEVEL SHORTWAVE TROUGH PUSHES ACROSS NEBRASKA INTO MINNESOTA
AND IOWA TONIGHT...WHICH WILL PUSH THE WHOLE SYSTEM EAST. THIS
WILL LEAD TO A DRASTIC DIFFERENCE IN WEATHER ACROSS THE EASTERN
AND WESTERN PARTS OF THE STATE OF NEBRASKA. ALTHOUGH MUCH OF THE
LOCAL AREA WILL BE BEHIND THE FRONT...THE FAR EASTERN AREAS...EAST
OF A KMCK TO KBBW TO KONL WILL STAY GENERALLY IN THE VICINITY OF
THE FRONT...SO MAY EXPERIENCE A MUCH DIFFERENT DAY.
TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN HAS BEEN
EXPERIENCED THE PAST SEVERAL DAYS DUE TO STRONG COLD AIR ADVECTION
BEHIND THE COLD FRONT. FOR EXAMPLE...IN THE 19.00Z SOUNDING FROM
LBF...THE 850MB TEMPERATURE WAS 25C AND BY 20.00Z...MODELS ARE
PROJECTING THE 850MB TEMPERATURE AT THE SAME LOCATION TO HAVE
DROPPED TO AROUND 9C. ALSO HELPING TO KEEP TEMPERATURES DOWN TODAY
WILL BE PLENTIFUL CLOUD COVER. THERE IS GOOD CONSISTENCY BETWEEN
THE MODELS OF A STRATUS DECK FILLING IN THIS MORNING ACROSS MUCH
OF WESTERN NEBRASKA...WHICH WILL STICK AROUND THROUGH THE MAJORITY
OF THE DAY. ALSO...WITH THE INCREASED MOISTURE AND EXTRA UPWARD
MOTION FROM THE PASSAGE OF THE UPPER LEVEL SYSTEM SHOULD SEE
PRECIPITATION THROUGH THE DAY. DO EXPECT MOST OF THIS
PRECIPITATION TO BE FAIRLY LIGHT THIS MORNING...MAYBE EVEN JUST
DRIZZLE AT TIMES. LOOKING FOR INCREASED PRECIPITATION AND
THUNDERSTORM CHANCES IN THE AFTERNOON...ESPECIALLY ALONG AND NEAR
THE COLD FRONT. ALTHOUGH MOST OF THIS ACTIVITY WILL BE EAST OF THE
AREA...COULD SEE A FEW ISOLATED THUNDERSTORMS BACK INTO CENTRAL
AND WESTERN NEBRASKA AS MODELS INDICATE A FEW HUNDRED J/KG OF CAPE
WILL REMAIN ACROSS MUCH OF THE AREA...AS WELL AS THE . AS THE
WHOLE SYSTEM MOVES NORTHEAST THIS EVENING...WILL LIKELY CONTINUE
TO SEE SOME LIGHT RAIN OVER NORTH CENTRAL NEBRASKA WITH
FRONTOGENESIS ONGOING ON THE BACKSIDE OF THE SYSTEM. THEN
EXPECTING THE RAIN TO BE OUT OF THE AREA BY MIDNIGHT.
ALSO BEHIND THE FRONT...A TIGHT PRESSURE GRADIENT WILL KEEP WINDS
STRONG OUT OF THE NORTH AND NORTHWEST TODAY ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEBRASKA. ALTHOUGH STRONG COLD AIR
ADVECTION WILL BE ONGOING...THE AREA WILL NOT BE IN AN AREA OF
SUBSIDENCE AS THE FOUR CORNERS SHORTWAVE APPROACHES. THIS ALONG
WITH STRATUS DECK KEEPING THE MIXED LAYER QUITE SHALLOW SO DON/T
BELIEVE WINDS WILL REACH ADVISORY CRITERIA.
WEATHER WILL BE QUIET THEN FOR SUNDAY THROUGH MONDAY. HIGH
PRESSURE SETTLES IN SUNDAY WITH LIGHT WINDS AND MOSTLY SUNNY
SKIES. TEMPERATURES WILL SEE SOME RECOVERY SUNDAY...BUT WILL BE
IN THE UPPER 60S AND LOW 70S. THE COOLEST LOCATIONS WILL BE OVER
NORTH CENTRAL NEBRASKA WHERE TEMPERATURES ALOFT WILL SEE LITTLE
WARMING. RIDGING ALOFT WILL AGAIN BE INFLUENCING THE REGION FOR
THE FIRST PART OF THE WORK WEEK AND WITH SOUTHERLY FLOW AT THE
SURFACE...TEMPERATURES WILL WARM AND MOISTURE WILL SEE A SLOW
INCREASE AS THE GULF OPENS UP. LOOKING FOR HIGHS MONDAY IN THE 70S
AND LOW 80S WITH BREEZY SOUTHERLY WINDS.
.LONG TERM...TUESDAY THROUGH FRIDAY
AS WAS STATED ABOVE...THERE ARE INDICATIONS THAT THE GULF WILL
START TO OPEN UP IN THE TUESDAY WEDNESDAY TIME-FRAME ALLOWING
MOISTURE TO BE PULLED INTO THE FORECAST AREA THROUGH THE REMAINDER
OF THE WEEK. IN TURN...TROUGHING MOVES INTO THE PACIFIC
NORTHWEST...KEEPING RIDGING OVER THE FORECAST AREA. THERE ARE
PLENTY OF DIFFERENCES IN MODEL SOLUTIONS WEDNESDAY AND
BEYOND...HOWEVER GENERAL CONSENSUS IS TROUGHING OVER THE PACIFIC
NORTHWEST WITH SEVERAL SYSTEMS PUSHING OVER THE RIDGE...MAINLY
AFFECTING THE DAKOTAS AND NORTHERN NEBRASKA. THE ECMWF SETTLES THE
UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST...AND THEN EJECTS SEVERAL
WEAKER SHORTWAVES OUT OF THE TROUGH AND PUSHING OVER THE RIDGE.
THIS WILL KEEP A LOT OF THE SHOWERS AND THUNDERSTORMS OVER THE
DAKOTAS AND THE NORTHERN PARTS OF NEBRASKA. THE GFS ON THE OTHER
HAND MOVES THE WHOLE SYSTEM ACROSS THE NORTHERN CONUS THROUGH THE
SECOND HALF OF THE WEEK. THIS SOLUTION WOULD PUSH A FRONT ACROSS
THE FORECAST AREA AND IN TURN BRING HIGHER RAIN CHANCES. REALLY
DIDN/T LOCK ONTO ANY ONE SOLUTION YET SO WILL JUST KEEP SLIGHT AND
CHANCE PRECIPITATION CHANCES IN THE FORECAST FOR THE OUTER
PERIODS. AS FOR TEMPERATURES THOUGH...LOOKING LIKE A WARM PERIOD
WITH TEMPERATURES ABOVE NORMAL IN THE UPPER 70S AND 80S...WITH
POSSIBLY 90S ON TUESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT/LONG TERM...BROOKS
AVIATION...CLB
000
FXUS63 KGID 191042
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
542 AM CDT SAT MAY 19 2012
.AVIATION...12Z KGRI TAF. VFR CONDITIONS EXPECTED THROUGH
MID-AFTERNOON...AT WHICH TIME MVFR CEILINGS WILL BE POSSIBLE
THROUGH THE END OF THE TAF PERIOD. SURFACE WINDS ARE DECREASING
WITH THE APPROACH OF A LOW LEVEL BAROCLINIC ZONE FROM THE WEST.
THE DIMINISHMENT OF THESE SURFACE WINDS...WORKING IN CONCERT WITH A
SHALLOW THERMAL INVERSION NEAR THE SURFACE AND THE PERSISTENCE OF
A 45-50KT LOW LEVEL JET STREAK OVER THE AREA...HAS RESULTED IN THE
DEVELOPMENT OF LLWS AT THE TERMINAL. THIS LLWS WILL LIKELY PERSIST
UNTIL AROUND 14Z...AT WHICH TIME THE AXIS OF STRONGEST 925MG-850MB
WINDS ARE EXPECTED TO PUSH OFF TO THE EAST OF THE TERMINAL. THE
LOW LEVEL BAROCLINIC ZONE IS EXPECTED TO CLEAR THE TERMINAL BY
EARLY TO MID-AFTERNOON WITH SURFACE WINDS BECOMING MORE
ESTABLISHED FROM THE NORTH/NORTHWEST THEREAFTER.
PRECIPITATION...ACCOMPANIED BY CEILINGS AS LOW AS 3000FT
AGL...WILL THEN FINISH OUT THE FORECAST PERIOD BEGINNING AT 21Z.
&&
.PREV DISCUSSION... /ISSUED 341 AM CDT SAT MAY 19 2012/
SHORT TERM...THROUGH 12Z TUESDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES TROUGHING OVER THE WESTERN CONUS...WITH RIDGING OVER THE
EAST. A 850MB JET STREAK OF AROUND 50KTS IS NOTED OVER THE CENTRAL
PLAINS...WITH MID AND UPPER LEVEL JET ENERGY REMAINING TO OUR
WEST...EXTENDING FROM THE SOUTHWESTERN CONUS INTO THE ROCKY
MOUNTAIN RANGE. WATER VAPOR IMAGERY SHOW A MID LEVEL SHORT WAVE AT
THE BASE OF THE WESTERN CONUS LONG WAVE TROUGH CURRENTLY OVER THE
FOUR CORNERS REGION. WATER VAPOR IMAGERY ALSO SHOWS INCREASED
VALUES OF MID LEVEL MOISTURE MOVING IN FROM THE PACIFIC INTO WEST
TEXAS AND THEN NORTH/NORTHEASTWARD INTO THE CENTRAL PLAINS. A MID
LEVEL DRY INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS
REGION NORTHEASTWARD INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE
AN AREA OF LOW PRESSURE IS NOTED OVER NORTHWESTERN KANSAS. A
WARM FRONT EXTENDS NORTHEASTWARD FROM THE LOW INTO NORTH CENTRAL
NEBRASKA AND SOUTH CENTRAL SOUTH DAKOTA...A COLD FRONT EXTENDS
WEST/SOUTHWEST FROM THE LOW INTO COLORADO...AND A DRY LINE
EXTENDS SOUTH FROM THE LOW ALONG THE COLORADO/KANSAS BORDER. THE
LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE SOUTH AS A
RESULT.
MODEL CONSENSUS CONTINUES TO SUGGEST THE MID LEVEL SHORT
WAVE...CURRENTLY OVER THE FOUR CORNERS REGION...WILL MOVE NORTHEAST
TODAY WITH A NEGATIVELY-TILTED TROUGH AXIS EXPECTED TO PUSH OVER
OUR AREA THIS AFTERNOON AND EVENING. THE SURFACE LOW...CURRENTLY
OVER NORTHWESTERN KANSAS...IS ALSO EXPECTED TO MOVE NORTHEAST THUS
ALLOWING THE LOW LEVEL BAROCLINIC ZONE TO PUSH ACROSS OUR AREA
THROUGH THE DAY. QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC
AND SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM THE 4KM
WRF-NMM...ALL SUGGEST DEEP SURFACE-BASED CONVECTION WILL BE
REALIZED ALONG AND AHEAD OF THE LOW LEVEL BAROCLINIC ZONE BY
MID-AFTERNOON...MOST LIKELY SOMEWHERE OVER THE EASTERN HALF OF
OUR CWA. SOUTHERLY LOW LEVEL FLOW IS CONTINUING TO PROMOTE
IMPRESSIVE LOW LEVEL MOISTURE FLUX INTO OUR AREA THIS
MORNING...WITH SURFACE DEW POINTS JUMPING ALMOST 10 DEGREES
THROUGH THE PAST 9 HOURS ACROSS THE EASTERN HALF OF THE CWA AND
NOW WELL INTO THE 50S AND APPROACHING THE 60S AS OF 08Z. THESE
INCREASING VALUES OF LOW LEVEL MOISTURE WILL HELP PROMOTE 0-1KM
MLCAPE VALUES OF 2000-2500J/KG ACROSS THE EASTERN HALF OF OUR CWA
BY MID-AFTERNOON. IN ADDITION TO THESE INCREASING VALUES OF
INSTABILITY...THE EMERGENCE OF A ~50KT 500MB JET STREAK WILL ALSO
HELP INCREASE DEEP-LAYER BULK SHEAR TO AROUND 40KTS...THUS MAKING
SUPER CELL DEVELOPMENT POSSIBLE AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE WHERE DISCRETE THUNDERSTORM DEVELOPMENT IS MORE LIKELY. BACK
ALONG THE LOW LEVEL BAROCLINIC ZONE...THE UNIDIRECTIONAL WIND
FIELD THROUGH MUCH OF THE TROPOSPHERE SUGGESTS A QUASI-LINEAR
CONVECTIVE SYSTEM WILL PRESENT ITSELF AS DEEP CONVECTION BECOMES
REALIZED...THUS PROVIDING MORE OF A WIND THREAT THAN ANYTHING
ELSE. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF SEVERE WEATHER
FOR THIS AFTERNOON AND EVENING. LATEST MODEL GUIDANCE DOES SUGGEST THE
LOW LEVEL BAROCLINIC ZONE WILL BE SOMEWHAT SLOWER THAN WHAT WAS
BEING INDICATED 24-48 HOURS AGO AND AS A RESULT...WILL GO AHEAD
EXPAND THE AREA OF POSSIBLE SEVERE WEATHER ACROSS OUR CWA...WHICH
WILL NOW INCLUDE AREAS ALONG AND EAST OF A LINE FROM SPALDING...TO
GRAND ISLAND...TO NATOMA WHICH IS WHERE THE SURFACE FRONT IS
CURRENTLY EXPECTED TO BE POSITIONED AT 21Z. WILL CONTINUE THE HAIL
AND WIND THREAT FOR THE REASONS MENTIONED ABOVE. 0-1KM HELICITY
DOES NOT APPEAR OVERLY IMPRESSIVE PER THE NAM...OPERATIONAL GFS
AND EC...GENERALLY AROUND 100M^2/S^2 ACROSS OUR SOUTHEAST AND
LESSER VALUES FARTHER NORTHWEST. THAT BEING SAID...FORECAST
PROXIMITY SOUNDINGS FROM THE NAM FOR LOCATIONS IMMEDIATELY AHEAD
OF THE LOW LEVEL BAROCLINIC ZONE...WHERE THE SURFACE WIND FIELD
WILL BE LOCALLY BACKED...DOES PRESENT A CLASSIC VEERING LOW LEVEL
WIND PROFILE THUS RESULTING IN AN AREA OF LOCALLY ENHANCED LOW
LEVEL HELICITY. THUS...ITS HARD TO COMPLETELY WRITE OFF THE THREAT
FOR TORNADOES...ESPECIALLY IF A DISCRETE SUPER CELL CAN BE
REALIZED IMMEDIATELY AHEAD OF THE LOW LEVEL BAROCLINIC ZONE. ALL
THAT BEING SAID...WILL GO AHEAD AND ALSO INCLUDE A TORNADO MENTION
IN THE HWO. SEVERE CONVECTION SHOULD PUSH EAST OF OUR AREA THIS
EVENING AS THE LOW LEVEL BAROCLINIC ZONE ALSO CLEARS OUR AREA TO
THE EAST. MID LEVEL DEFORMATION TO THE NORTHWEST OF THE MID LEVEL
SHORT WAVE WILL LIKELY PROMOTE FURTHER PRECIPITATION ACROSS
NORTHERN PORTIONS OF THE CWA THROUGH 06Z...WITH PRECIPITATION
ENDING ALTOGETHER THEREAFTER AS THE MID LEVEL SHORT WAVE PUSHES
OFF TO THE EAST. AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PRESENT DRY CONDITIONS TO THE AREA THROUGH THE REMAINDER OF THE
SHORT TERM FORECAST PERIOD.
TODAY REMAINS A TRICKY TEMPERATURE FORECAST WITH TEMPERATURES
REMAINING HIGHLY DEPENDENT UPON THE POSITION OF THE LOW LEVEL
BAROCLINIC ZONE...AS WELL AS CLOUD COVER AND PRECIPITATION.
PREVIOUS SHIFTS OPTED TO RAISE TEMPERATURES SOMEWHAT ACROSS OUR
EAST/SOUTHEAST AND GIVEN THE NOW SLOWER EXPECTED PROGRESSION OF
THE LOW LEVEL BAROCLINIC ZONE...THIS APPEARS TO BE GREAT DECISION.
THAT BEING SAID...AM BECOMING INCREASINGLY CONCERNED THAT
TEMPERATURES ACROSS OUR NORTH/NORTHWEST COULD STRUGGLE MIGHTILY AS
THE LOW LEVEL BAROCLINIC ZONE CLEARS DURING THE 12Z-15Z
TIME FRAME...AND CLOUD COVER AND PRECIPITATION OVERTAKE THE AREA.
ATYPICAL DIURNALS WILL LIKELY BE OBSERVED ACROSS OUR
NORTH/NORTHWEST WITH DAYTIME TEMPERATURES NOT LIKELY CLIMBING MORE
THAN 10 DEGREES ABOVE EARLY MORNING TEMPERATURES. WENT AHEAD AND
DECREASED TODAYS HIGHS ACROSS OUR NORTH/NORTHWEST A FEW DEGREES TO
GET THEM INTO THE LOW TO MID 70S. LOCATIONS FARTHER SOUTHEAST WILL
LIKELY SEE MUCH WARMER WEATHER AS THEY REMAIN PRE-FRONTAL LONGER
AND THE INFILTRATION OF A MID LEVEL DRY INTRUSION ALLOWS FOR MORE
SUNSHINE BEFORE DEEP CONVECTION INITIALIZES DURING THE AFTERNOON.
LOW TO MID 80S WILL LIKELY BE NOTED ACROSS THE SOUTHEASTERN HALF
OF OUR CWA AS A RESULT. THE INTRUSION OF A SURFACE RIDGE WILL THEN
PRESENT COOLER CONDITIONS CWA-WIDE SUNDAY AND MONDAY...WITH
AFTERNOON HIGHS LIKELY REMAINING IN THE 70S FOR THE MOST PART.
LONG TERM...TUESDAY THROUGH FRIDAY. MAIN FORECAST CONCERN WILL BE
CHANCES FOR THUNDERSTORMS WEDNESDAY THROUGH FRIDAY.
TUESDAY AND TUESDAY NIGHT AN UPPER LEVEL RIDGE MOVES THROUGH THE
AREA AND EXPECT WARM TEMPERATURES. THE PRESSURE GRADIENT TIGHTENS
DURING THE DAY AND SOUTH WINDS SHOULD INCREASE DURING THE DAY.
TUESDAY NIGHT A COLD FRONT APPROACHES THE AREA. THIS FRONT MOVES
INTO THE FORECAST AREA ON WEDNESDAY. AS AN UPPER LEVEL WAVE MOVES
INTO THE AREA AREA THE CHANCE OF THUNDERSTORMS INCREASES. BY
WEDNESDAY NIGHT THE FRONT STALLS OUT IN THE SOUTHEAST PART OF THE
AREA AND THUNDERSTORMS DEVELOP ALONG THE FRONT. THERE IS 2500 TO
3000 J/KG CAPE DURING THE AFTERNOON AND EVENING AND THERE COULD BE
SOME STRONGER THUNDERSTORMS POSSIBLE. THE UPPER WAVE MOVES THROUGH
THE AREA ON THURSDAY AND THE THUNDERSTORM CHANCES DIMINISH.
A SECONDARY WAVE MOVES THROUGH THURSDAY NIGHT INTO FRIDAY AND THERE
IS ANOTHER SURFACE LOW THAT DEVELOPS IN KANSAS WITH A CHANCE FOR
THUNDERSTORMS TO THE NORTH OF THE FRONT THURSDAY NIGHT. ON FRIDAY
THE WAVE MOVES OUT AND THUNDERSTORMS COME TO AN END.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/SHORT TERM...BRYANT
000
FXUS63 KLBF 190901
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
401 AM CDT SAT MAY 19 2012
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
FORECAST FOCUS THROUGH THIS PERIOD IS ON PRECIPITATION CHANCES AND
WINDS TODAY AND TONIGHT...THEN WITH TEMPERATURES THROUGH THE PERIOD.
AS OF 08Z...WATER VAPOR IMAGERY SHOWED RIDGING OVER THE GREAT
LAKES AND EASTERN CONUS WITH TROUGHING ACROSS THE INTER-MOUNTAIN
WEST. THIS TROUGH WAS CHARACTERIZED BY TWO MAIN PV ANOMALIES...ONE
OVER ALBERTA INTO MONTANA AND THE OTHER OVER THE FOUR CORNERS. IN
ADDITION...A LEAD WEAK WAVE HAD PUSHED ACROSS NEBRASKA EARLIER ON
FRIDAY EVENING...WHICH HAD HELPED FIRE THE CONVECTION THAT OCCURRED.
THE COLD FRONT HAD PASSED THROUGH MUCH OF THE FORECAST AREA AS OF
08Z AS IT WAS LOCATED FROM NORTHEAST SOUTH DAKOTA INTO WESTERN
KANSAS...ROUGHLY FROM KP67 IN NORTH DAKOTA TO KONL TO KMCK IN
NEBRASKA AND SOUTHWEST TO KSPD IN SOUTHEAST COLORADO. CONVECTION
HAD FOR THE MOST PART MOVED OUT OF THE FORECAST AREA...LEAVING
MANY OUTFLOW BOUNDARIES ACROSS THE REGION WHICH HAS IMPACTED WINDS
OVERNIGHT. TEMPERATURES HAD BEEN SLOWLY FALLING OVERNIGHT AS THE
FRONT MOVED SOUTHEAST...HOWEVER LOCATIONS AHEAD OF THE FRONT
REMAIN IN THE 70S.
THE FRONT WON/T SEE MUCH MOVEMENT UNTIL AFTER 20.00Z WHEN THE
UPPER LEVEL SHORTWAVE TROUGH PUSHES ACROSS NEBRASKA INTO MINNESOTA
AND IOWA TONIGHT...WHICH WILL PUSH THE WHOLE SYSTEM EAST. THIS
WILL LEAD TO A DRASTIC DIFFERENCE IN WEATHER ACROSS THE EASTERN
AND WESTERN PARTS OF THE STATE OF NEBRASKA. ALTHOUGH MUCH OF THE
LOCAL AREA WILL BE BEHIND THE FRONT...THE FAR EASTERN AREAS...EAST
OF A KMCK TO KBBW TO KONL WILL STAY GENERALLY IN THE VICINITY OF
THE FRONT...SO MAY EXPERIENCE A MUCH DIFFERENT DAY.
TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN HAS BEEN
EXPERIENCED THE PAST SEVERAL DAYS DUE TO STRONG COLD AIR ADVECTION
BEHIND THE COLD FRONT. FOR EXAMPLE...IN THE 19.00Z SOUNDING FROM
LBF...THE 850MB TEMPERATURE WAS 25C AND BY 20.00Z...MODELS ARE
PROJECTING THE 850MB TEMPERATURE AT THE SAME LOCATION TO HAVE
DROPPED TO AROUND 9C. ALSO HELPING TO KEEP TEMPERATURES DOWN TODAY
WILL BE PLENTIFUL CLOUD COVER. THERE IS GOOD CONSISTENCY BETWEEN
THE MODELS OF A STRATUS DECK FILLING IN THIS MORNING ACROSS MUCH
OF WESTERN NEBRASKA...WHICH WILL STICK AROUND THROUGH THE MAJORITY
OF THE DAY. ALSO...WITH THE INCREASED MOISTURE AND EXTRA UPWARD
MOTION FROM THE PASSAGE OF THE UPPER LEVEL SYSTEM SHOULD SEE
PRECIPITATION THROUGH THE DAY. DO EXPECT MOST OF THIS
PRECIPITATION TO BE FAIRLY LIGHT THIS MORNING...MAYBE EVEN JUST
DRIZZLE AT TIMES. LOOKING FOR INCREASED PRECIPITATION AND
THUNDERSTORM CHANCES IN THE AFTERNOON...ESPECIALLY ALONG AND NEAR
THE COLD FRONT. ALTHOUGH MOST OF THIS ACTIVITY WILL BE EAST OF THE
AREA...COULD SEE A FEW ISOLATED THUNDERSTORMS BACK INTO CENTRAL
AND WESTERN NEBRASKA AS MODELS INDICATE A FEW HUNDRED J/KG OF CAPE
WILL REMAIN ACROSS MUCH OF THE AREA...AS WELL AS THE . AS THE
WHOLE SYSTEM MOVES NORTHEAST THIS EVENING...WILL LIKELY CONTINUE
TO SEE SOME LIGHT RAIN OVER NORTH CENTRAL NEBRASKA WITH
FRONTOGENESIS ONGOING ON THE BACKSIDE OF THE SYSTEM. THEN
EXPECTING THE RAIN TO BE OUT OF THE AREA BY MIDNIGHT.
ALSO BEHIND THE FRONT...A TIGHT PRESSURE GRADIENT WILL KEEP WINDS
STRONG OUT OF THE NORTH AND NORTHWEST TODAY ACROSS MUCH OF
WESTERN AND NORTH CENTRAL NEBRASKA. ALTHOUGH STRONG COLD AIR
ADVECTION WILL BE ONGOING...THE AREA WILL NOT BE IN AN AREA OF
SUBSIDENCE AS THE FOUR CORNERS SHORTWAVE APPROACHES. THIS ALONG
WITH STRATUS DECK KEEPING THE MIXED LAYER QUITE SHALLOW SO DON/T
BELIEVE WINDS WILL REACH ADVISORY CRITERIA.
WEATHER WILL BE QUIET THEN FOR SUNDAY THROUGH MONDAY. HIGH
PRESSURE SETTLES IN SUNDAY WITH LIGHT WINDS AND MOSTLY SUNNY
SKIES. TEMPERATURES WILL SEE SOME RECOVERY SUNDAY...BUT WILL BE
IN THE UPPER 60S AND LOW 70S. THE COOLEST LOCATIONS WILL BE OVER
NORTH CENTRAL NEBRASKA WHERE TEMPERATURES ALOFT WILL SEE LITTLE
WARMING. RIDGING ALOFT WILL AGAIN BE INFLUENCING THE REGION FOR
THE FIRST PART OF THE WORK WEEK AND WITH SOUTHERLY FLOW AT THE
SURFACE...TEMPERATURES WILL WARM AND MOISTURE WILL SEE A SLOW
INCREASE AS THE GULF OPENS UP. LOOKING FOR HIGHS MONDAY IN THE 70S
AND LOW 80S WITH BREEZY SOUTHERLY WINDS.
.LONG TERM...TUESDAY THROUGH FRIDAY
AS WAS STATED ABOVE...THERE ARE INDICATIONS THAT THE GULF WILL
START TO OPEN UP IN THE TUESDAY WEDNESDAY TIME-FRAME ALLOWING
MOISTURE TO BE PULLED INTO THE FORECAST AREA THROUGH THE REMAINDER
OF THE WEEK. IN TURN...TROUGHING MOVES INTO THE PACIFIC
NORTHWEST...KEEPING RIDGING OVER THE FORECAST AREA. THERE ARE
PLENTY OF DIFFERENCES IN MODEL SOLUTIONS WEDNESDAY AND
BEYOND...HOWEVER GENERAL CONSENSUS IS TROUGHING OVER THE PACIFIC
NORTHWEST WITH SEVERAL SYSTEMS PUSHING OVER THE RIDGE...MAINLY
AFFECTING THE DAKOTAS AND NORTHERN NEBRASKA. THE ECMWF SETTLES THE
UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST...AND THEN EJECTS SEVERAL
WEAKER SHORTWAVES OUT OF THE TROUGH AND PUSHING OVER THE RIDGE.
THIS WILL KEEP A LOT OF THE SHOWERS AND THUNDERSTORMS OVER THE
DAKOTAS AND THE NORTHERN PARTS OF NEBRASKA. THE GFS ON THE OTHER
HAND MOVES THE WHOLE SYSTEM ACROSS THE NORTHERN CONUS THROUGH THE
SECOND HALF OF THE WEEK. THIS SOLUTION WOULD PUSH A FRONT ACROSS
THE FORECAST AREA AND IN TURN BRING HIGHER RAIN CHANCES. REALLY
DIDN/T LOCK ONTO ANY ONE SOLUTION YET SO WILL JUST KEEP SLIGHT AND
CHANCE PRECIPITATION CHANCES IN THE FORECAST FOR THE OUTER
PERIODS. AS FOR TEMPERATURES THOUGH...LOOKING LIKE A WARM PERIOD
WITH TEMPERATURES ABOVE NORMAL IN THE UPPER 70S AND 80S...WITH
POSSIBLY 90S ON TUESDAY.
&&
.AVIATION...
FOR THE KVTN AND KLBF TERMINALS THROUGH 12Z SUNDAY.
EXPECT OVERCAST SKIES TODAY AND THIS EVENING WITH MVFR CIGS POSSIBLE
AT THE KLBF TERMINAL. CIGS WILL LWR TO AROUND 2500 FT AGL AND WILL
PERIODICALLY DROP DOWN TO 1500 FT AGL THROUGH 16Z. LIGHT RAIN IS
EXPECTED TO DEVELOP THIS AFTERNOON AS AN UPPER LEVEL TROUGH OF LOW
PRESSURE TRACKS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. LOOK FOR
CIGS TO BEGIN TO RISE ABOVE 2500 FT AGL THIS EVENING WITH CLEARING
SKIES EXPECTED AFTER 06Z TONIGHT. EXPECT NORTHERLY WINDS OF 15 TO 25
KTS WITH FREQUENT GUSTS TO 30 KTS TODAY. WINDS WILL DIMINISH TO
AROUND 10 KTS THIS EVENING.
FOR THE KVTN TERMINAL...MVFR SKIES ARE EXPECTED TODAY WITH CIGS AON
2500 FT AGL. LIGHT RAIN SHOWERS ARE POSSIBLE...MAINLY AFTER
18Z...PERSISTING THROUGH MID EVENING. SCATTERED TO BROKEN CLOUDINESS
IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS BEFORE CLEARING
AROUND 12Z SUNDAY. WINDS TODAY WILL BE FROM THE NORTH NORTHWEST AT
15 TO 25 KTS WITH SOME PERIODIC GUSTS TO 30 KTS. WINDS WILL DIMINISH
TO AROUND 10 KTS AFTER SUNSET THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT/LONG TERM...BROOKS
AVIATION...CLB
000
FXUS63 KGID 190841
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
341 AM CDT SAT MAY 19 2012
.SHORT TERM...THROUGH 12Z TUESDAY. OVERNIGHT UPPER AIR ANALYSIS
INDICATES TROUGHING OVER THE WESTERN CONUS...WITH RIDGING OVER THE
EAST. A 850MB JET STREAK OF AROUND 50KTS IS NOTED OVER THE CENTRAL
PLAINS...WITH MID AND UPPER LEVEL JET ENERGY REMAINING TO OUR
WEST...EXTENDING FROM THE SOUTHWESTERN CONUS INTO THE ROCKY
MOUNTAIN RANGE. WATER VAPOR IMAGERY SHOW A MID LEVEL SHORT WAVE AT
THE BASE OF THE WESTERN CONUS LONG WAVE TROUGH CURRENTLY OVER THE
FOUR CORNERS REGION. WATER VAPOR IMAGERY ALSO SHOWS INCREASED
VALUES OF MID LEVEL MOISTURE MOVING IN FROM THE PACIFIC INTO WEST
TEXAS AND THEN NORTH/NORTHEASTWARD INTO THE CENTRAL PLAINS. A MID
LEVEL DRY INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS
REGION NORTHEASTWARD INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE
AN AREA OF LOW PRESSURE IS NOTED OVER NORTHWESTERN KANSAS. A
WARM FRONT EXTENDS NORTHEASTWARD FROM THE LOW INTO NORTH CENTRAL
NEBRASKA AND SOUTH CENTRAL SOUTH DAKOTA...A COLD FRONT EXTENDS
WEST/SOUTHWEST FROM THE LOW INTO COLORADO...AND A DRY LINE
EXTENDS SOUTH FROM THE LOW ALONG THE COLORADO/KANSAS BORDER. THE
LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE SOUTH AS A
RESULT.
MODEL CONSENSUS CONTINUES TO SUGGEST THE MID LEVEL SHORT
WAVE...CURRENTLY OVER THE FOUR CORNERS REGION...WILL MOVE NORTHEAST
TODAY WITH A NEGATIVELY-TILTED TROUGH AXIS EXPECTED TO PUSH OVER
OUR AREA THIS AFTERNOON AND EVENING. THE SURFACE LOW...CURRENTLY
OVER NORTHWESTERN KANSAS...IS ALSO EXPECTED TO MOVE NORTHEAST THUS
ALLOWING THE LOW LEVEL BAROCLINIC ZONE TO PUSH ACROSS OUR AREA
THROUGH THE DAY. QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC
AND SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM THE 4KM
WRF-NMM...ALL SUGGEST DEEP SURFACE-BASED CONVECTION WILL BE
REALIZED ALONG AND AHEAD OF THE LOW LEVEL BAROCLINIC ZONE BY
MID-AFTERNOON...MOST LIKELY SOMEWHERE OVER THE EASTERN HALF OF
OUR CWA. SOUTHERLY LOW LEVEL FLOW IS CONTINUING TO PROMOTE
IMPRESSIVE LOW LEVEL MOISTURE FLUX INTO OUR AREA THIS
MORNING...WITH SURFACE DEW POINTS JUMPING ALMOST 10 DEGREES
THROUGH THE PAST 9 HOURS ACROSS THE EASTERN HALF OF THE CWA AND
NOW WELL INTO THE 50S AND APPROACHING THE 60S AS OF 08Z. THESE
INCREASING VALUES OF LOW LEVEL MOISTURE WILL HELP PROMOTE 0-1KM
MLCAPE VALUES OF 2000-2500J/KG ACROSS THE EASTERN HALF OF OUR CWA
BY MID-AFTERNOON. IN ADDITION TO THESE INCREASING VALUES OF
INSTABILITY...THE EMERGENCE OF A ~50KT 500MB JET STREAK WILL ALSO
HELP INCREASE DEEP-LAYER BULK SHEAR TO AROUND 40KTS...THUS MAKING
SUPER CELL DEVELOPMENT POSSIBLE AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE WHERE DISCRETE THUNDERSTORM DEVELOPMENT IS MORE LIKELY. BACK
ALONG THE LOW LEVEL BAROCLINIC ZONE...THE UNIDIRECTIONAL WIND
FIELD THROUGH MUCH OF THE TROPOSPHERE SUGGESTS A QUASI-LINEAR
CONVECTIVE SYSTEM WILL PRESENT ITSELF AS DEEP CONVECTION BECOMES
REALIZED...THUS PROVIDING MORE OF A WIND THREAT THAN ANYTHING
ELSE. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF SEVERE WEATHER
FOR THIS AFTERNOON AND EVENING. LATEST MODEL GUIDANCE DOES SUGGEST THE
LOW LEVEL BAROCLINIC ZONE WILL BE SOMEWHAT SLOWER THAN WHAT WAS
BEING INDICATED 24-48 HOURS AGO AND AS A RESULT...WILL GO AHEAD
EXPAND THE AREA OF POSSIBLE SEVERE WEATHER ACROSS OUR CWA...WHICH
WILL NOW INCLUDE AREAS ALONG AND EAST OF A LINE FROM SPALDING...TO
GRAND ISLAND...TO NATOMA WHICH IS WHERE THE SURFACE FRONT IS
CURRENTLY EXPECTED TO BE POSITIONED AT 21Z. WILL CONTINUE THE HAIL
AND WIND THREAT FOR THE REASONS MENTIONED ABOVE. 0-1KM HELICITY
DOES NOT APPEAR OVERLY IMPRESSIVE PER THE NAM...OPERATIONAL GFS
AND EC...GENERALLY AROUND 100M^2/S^2 ACROSS OUR SOUTHEAST AND
LESSER VALUES FARTHER NORTHWEST. THAT BEING SAID...FORECAST
PROXIMITY SOUNDINGS FROM THE NAM FOR LOCATIONS IMMEDIATELY AHEAD
OF THE LOW LEVEL BAROCLINIC ZONE...WHERE THE SURFACE WIND FIELD
WILL BE LOCALLY BACKED...DOES PRESENT A CLASSIC VEERING LOW LEVEL
WIND PROFILE THUS RESULTING IN AN AREA OF LOCALLY ENHANCED LOW
LEVEL HELICITY. THUS...ITS HARD TO COMPLETELY WRITE OFF THE THREAT
FOR TORNADOES...ESPECIALLY IF A DISCRETE SUPER CELL CAN BE
REALIZED IMMEDIATELY AHEAD OF THE LOW LEVEL BAROCLINIC ZONE. ALL
THAT BEING SAID...WILL GO AHEAD AND ALSO INCLUDE A TORNADO MENTION
IN THE HWO. SEVERE CONVECTION SHOULD PUSH EAST OF OUR AREA THIS
EVENING AS THE LOW LEVEL BAROCLINIC ZONE ALSO CLEARS OUR AREA TO
THE EAST. MID LEVEL DEFORMATION TO THE NORTHWEST OF THE MID LEVEL
SHORT WAVE WILL LIKELY PROMOTE FURTHER PRECIPITATION ACROSS
NORTHERN PORTIONS OF THE CWA THROUGH 06Z...WITH PRECIPITATION
ENDING ALTOGETHER THEREAFTER AS THE MID LEVEL SHORT WAVE PUSHES
OFF TO THE EAST. AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PRESENT DRY CONDITIONS TO THE AREA THROUGH THE REMAINDER OF THE
SHORT TERM FORECAST PERIOD.
TODAY REMAINS A TRICKY TEMPERATURE FORECAST WITH TEMPERATURES
REMAINING HIGHLY DEPENDENT UPON THE POSITION OF THE LOW LEVEL
BAROCLINIC ZONE...AS WELL AS CLOUD COVER AND PRECIPITATION.
PREVIOUS SHIFTS OPTED TO RAISE TEMPERATURES SOMEWHAT ACROSS OUR
EAST/SOUTHEAST AND GIVEN THE NOW SLOWER EXPECTED PROGRESSION OF
THE LOW LEVEL BAROCLINIC ZONE...THIS APPEARS TO BE GREAT DECISION.
THAT BEING SAID...AM BECOMING INCREASINGLY CONCERNED THAT
TEMPERATURES ACROSS OUR NORTH/NORTHWEST COULD STRUGGLE MIGHTILY AS
THE LOW LEVEL BAROCLINIC ZONE CLEARS DURING THE 12Z-15Z
TIME FRAME...AND CLOUD COVER AND PRECIPITATION OVERTAKE THE AREA.
ATYPICAL DIURNALS WILL LIKELY BE OBSERVED ACROSS OUR
NORTH/NORTHWEST WITH DAYTIME TEMPERATURES NOT LIKELY CLIMBING MORE
THAN 10 DEGREES ABOVE EARLY MORNING TEMPERATURES. WENT AHEAD AND
DECREASED TODAYS HIGHS ACROSS OUR NORTH/NORTHWEST A FEW DEGREES TO
GET THEM INTO THE LOW TO MID 70S. LOCATIONS FARTHER SOUTHEAST WILL
LIKELY SEE MUCH WARMER WEATHER AS THEY REMAIN PRE-FRONTAL LONGER
AND THE INFILTRATION OF A MID LEVEL DRY INTRUSION ALLOWS FOR MORE
SUNSHINE BEFORE DEEP CONVECTION INITIALIZES DURING THE AFTERNOON.
LOW TO MID 80S WILL LIKELY BE NOTED ACROSS THE SOUTHEASTERN HALF
OF OUR CWA AS A RESULT. THE INTRUSION OF A SURFACE RIDGE WILL THEN
PRESENT COOLER CONDITIONS CWA-WIDE SUNDAY AND MONDAY...WITH
AFTERNOON HIGHS LIKELY REMAINING IN THE 70S FOR THE MOST PART.
.LONG TERM...TUESDAY THROUGH FRIDAY. MAIN FORECAST CONCERN WILL BE
CHANCES FOR THUNDERSTORMS WEDNESDAY THROUGH FRIDAY.
TUESDAY AND TUESDAY NIGHT AN UPPER LEVEL RIDGE MOVES THROUGH THE
AREA AND EXPECT WARM TEMPERATURES. THE PRESSURE GRADIENT TIGHTENS
DURING THE DAY AND SOUTH WINDS SHOULD INCREASE DURING THE DAY.
TUESDAY NIGHT A COLD FRONT APPROACHES THE AREA. THIS FRONT MOVES
INTO THE FORECAST AREA ON WEDNESDAY. AS AN UPPER LEVEL WAVE MOVES
INTO THE AREA AREA THE CHANCE OF THUNDERSTORMS INCREASES. BY
WEDNESDAY NIGHT THE FRONT STALLS OUT IN THE SOUTHEAST PART OF THE
AREA AND THUNDERSTORMS DEVELOP ALONG THE FRONT. THERE IS 2500 TO
3000 J/KG CAPE DURING THE AFTERNOON AND EVENING AND THERE COULD BE
SOME STRONGER THUNDERSTORMS POSSIBLE. THE UPPER WAVE MOVES THROUGH
THE AREA ON THURSDAY AND THE THUNDERSTORM CHANCES DIMINISH.
A SECONDARY WAVE MOVES THROUGH THURSDAY NIGHT INTO FRIDAY AND THERE
IS ANOTHER SURFACE LOW THAT DEVELOPS IN KANSAS WITH A CHANCE FOR
THUNDERSTORMS TO THE NORTH OF THE FRONT THURSDAY NIGHT. ON FRIDAY
THE WAVE MOVES OUT AND THUNDERSTORMS COME TO AN END.
&&
.PREV DISCUSSION... /ISSUED 1202 AM CDT SAT MAY 19 2012/
AVIATION...06Z KGRI TAF. VFR CONDITIONS EXPECTED THROUGH
MID-AFTERNOON SATURDAY...AT WHICH TIME MVFR CEILINGS WILL BE
POSSIBLE THROUGH THE END OF THE TAF PERIOD. SURFACE WINDS WILL
REMAIN FROM THE SOUTH BUT DECREASE IN INTENSITY AS A LOW LEVEL
BAROCLINIC ZONE APPROACHES FROM THE WEST. BY 11Z THE SURFACE WINDS
MAY HAVE DECREASED ENOUGH THUS ALLOWING FOR THE DEVELOPMENT OF
LLWS DUE TO A SHALLOW THERMAL INVERSION NEAR THE SURFACE AND THE
PERSISTENCE OF A 45-50KT LOW LEVEL JET STREAK. ANY LLWS THAT DOES
DEVELOP SHOULD NOT PERSIST FOR MORE THAN A FEW HOURS HOWEVER AS
THE AXIS OF STRONGEST 925MG-850MB WINDS PUSHES OFF TO THE EAST OF
THE TERMINAL. THE LOW LEVEL BAROCLINIC ZONE IS EXPECTED TO CLEAR
THE TERMINAL BY EARLY TO MID-AFTERNOON WITH SURFACE WINDS BECOMING
MORE ESTABLISHED FROM THE NORTH/NORTHWEST THEREAFTER.
PRECIPITATION...ACCOMPANIED BY CEILINGS AS LOW AS 3000FT AGL...WILL
THEN FINISH OUT THE FORECAST PERIOD BEGINNING AT 21Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...BRYANT
000
FXUS63 KOAX 190815
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
315 AM CDT SAT MAY 19 2012
.DISCUSSION...
THUNDERSTORM POTENTIAL THROUGH TONIGHT IS THE MAIN FORECAST CONCERN.
SOME SEVERE STORMS APPEAR POSSIBLE ALONG WITH LOCALLY HEAVY RAIN
MAINLY FROM LATE AFTERNOON THROUGH THE EVENING.
500 MB CHART FROM LAST EVENING SHOWED A TROUGH OVER THE ROCKIES AND
STARTING TO MOVE OUT INTO THE HIGH PLAINS. 12 HOUR HEIGHT FALLS WERE
NOT ALL THAT IMPRESSIVE...WITH A MAX OF 40 METERS AT GRAND JUNCTION.
MOISTURE AT 850 MB WAS STILL MEAGER...BUT VALUES UP TO AROUND 10
DEGREES CELSIUS WERE NOTED FROM PARTS OF TEXAS INTO SOUTHWESTERN
OKLAHOMA.
A COLD FRONT WILL CONTINUE TO PRESS EASTWARD ACROSS THE FORECAST
AREA THROUGH TONIGHT. HIGHS THIS AFTERNOON SHOULD BE MAINLY IN THE
80S...WITH MID OR UPPER 70S MORE LIKELY IN OUR FAR WESTERN ZONES.
ALTHOUGH SOME STORMS ARE POSSIBLE THROUGH THE MORNING AND INTO
EARLY AFTERNOON...IT APPEARS MAIN SEVERE RISK IS 4 PM TO 10 PM.
0 TO 6 KILOMETER BULK SHEAR VALUES ARE EXPECTED TO BE 30 TO 50
KNOTS...MORE THAN ADEQUATE FOR ORGANIZED STORMS.
FRONT WILL CONTINUE TO MOVE EASTWARD TONIGHT...WITH PRECIPITATION
CHANCES GENERALLY DECREASING AS THE NIGHT PROGRESSES. KEPT A SMALL
POP SUNDAY MORNING FOR PARTS OF THE AREA AS SOME SHOWERS MAY LINGER.
SUNDAY WILL BE NOTICEABLY COOLER WITH A NORTH BREEZE...AND EXPECT
MOST READINGS TO TOP OUT IN THE 70S.
EXPECT THE PERIOD FROM MONDAY THROUGH TUESDAY TO BE DRY...AND
HAVE TEMPERATURES SLOWLY MODERATING THROUGH MID WEEK. MID
TROPOSPHERIC RIDGE WILL BUILD OVER THE ROCKIES AND OUT INTO THE
PLAINS MONDAY/TUESDAY AS A TROUGH DIGS IN OVER THE WESTERN PART OF
THE NATION. THIS TURNS OUR MID LEVEL FLOW TO SOUTHWEST BY TUESDAY
NIGHT. HELD OFF A BIT ON RAIN CHANCES UNTIL WEDNESDAY...BUT WILL
NEED TO MONITOR LATER FORECASTS. MIGHT NEED TO ADD A CHANCE OF
THUNDERSTORMS TUESDAY NIGHT AS 850 MB MOISTURE RETURNS WITH LOW
LEVEL JET.
OTHERWISE MODELS AGREE ON GENERAL POTENTIALLY ACTIVE PATTERN FOR THE
MID AND LATTER PART OF THE WEEK...BUT DIFFER IN REGARDS TO DETAILS.
DID NOT HAVE A STRONG MODEL PREFERENCE AT THIS TIME.
MILLER
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS EXPECTED THROUGH THE LATTER PORTION OF THE FCST PD.
A COLD FRONT IS EXPECTED TO PUSH ACROSS ERN NEB SAT EVENING WHEN
CAP BREAKS...PRODUCING SCT TSRA OVER THE REGION. FROPA WILL COME
FIRST AT KOFK TWD 19/22Z...BUT NOT TILL ABOUT 20/04Z AT KOMA AND
KLNK. OCCASIONAL MVFR CONDITIONS BTWN 19/22Z-20/05Z ARE PROBABLE
AT ALL TERMINALS AT THAT TIME. MVFR CIGS THEN SETTLE IN THE REST
OF THE FCST PD.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
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