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000
FXCA62 TJSJ 291857
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
257 PM AST FRI MAY 29 2015

.DISCUSSION...HEAVY SHOWERS AND STRONG THUNDERSTORMS DEVELOPED
OVER THE NORTH CENTRAL SECTIONS OF PUERTO RICO INCLUDING THE SAN
JUAN METROPOLITAN AREA. RADAR ESTIMATES WERE BETWEEN 2 TO 3 INCHES
MAINLY OVER THE MUNICIPALITIES OF BAYAMON AND VEGA BAJA. AT THIS
MOMENT MOST OF THESE SHOWERS AND THUNDERSTORMS HAVE SOME
INTENSITY. THESE SHOWERS ARE EXPECTED TO CONTINUE THROUGH THE
EVENING HOURS.

RADAR AND SATELLITE IMAGES ARE SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS OVER THE LOCAL CARIBBEAN WATERS. THESE SHOWERS AND
THUNDERSTORMS WILL MOVE SLOWLY NW AND AFFECT THE EASTERN AND
SOUTHERN PORTIONS OF PUERTO RICO FROM LATE TONIGHT THROUGH
SATURDAY MID MORNING.

ON SATURDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY
LEAD TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY
ACROSS PARTS OF THE NORTHERN HALF OF PUERTO RICO.

THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI THROUGH TONIGHT.
THIS WEATHER PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM
ACROSS THE THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE
ACROSS THE AREA THROUGH EARLY SUNDAY.

&&

.AVIATION...MVFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS TJSJ
THROUGH AT LEAST 29/23Z. MAINLY VFR CONDITIONS ARE EXPECTED TO
PREVAIL ACROSS ALL TAF SITES THROUGH 30/12Z. HOWEVER...PASSING
SHOWERS WILL AFFECT THE LOCAL TAF SITES FROM TIME TO TIME. LOW LEVEL
WINDS WILL BE MAINLY SOUTHEAST AT 10 KTS.

&&

.MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TONIGHT. DETERIORATING CONDITIONS
EXPECTED TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR
THUNDERSTORM DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF
THE REGIONAL WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

71/10




000
FXCA62 TJSJ 291857
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
257 PM AST FRI MAY 29 2015

.DISCUSSION...HEAVY SHOWERS AND STRONG THUNDERSTORMS DEVELOPED
OVER THE NORTH CENTRAL SECTIONS OF PUERTO RICO INCLUDING THE SAN
JUAN METROPOLITAN AREA. RADAR ESTIMATES WERE BETWEEN 2 TO 3 INCHES
MAINLY OVER THE MUNICIPALITIES OF BAYAMON AND VEGA BAJA. AT THIS
MOMENT MOST OF THESE SHOWERS AND THUNDERSTORMS HAVE SOME
INTENSITY. THESE SHOWERS ARE EXPECTED TO CONTINUE THROUGH THE
EVENING HOURS.

RADAR AND SATELLITE IMAGES ARE SHOWING A LARGE AREA OF SHOWERS AND
THUNDERSTORMS OVER THE LOCAL CARIBBEAN WATERS. THESE SHOWERS AND
THUNDERSTORMS WILL MOVE SLOWLY NW AND AFFECT THE EASTERN AND
SOUTHERN PORTIONS OF PUERTO RICO FROM LATE TONIGHT THROUGH
SATURDAY MID MORNING.

ON SATURDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY
LEAD TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY
ACROSS PARTS OF THE NORTHERN HALF OF PUERTO RICO.

THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI THROUGH TONIGHT.
THIS WEATHER PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM
ACROSS THE THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE
ACROSS THE AREA THROUGH EARLY SUNDAY.

&&

.AVIATION...MVFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS TJSJ
THROUGH AT LEAST 29/23Z. MAINLY VFR CONDITIONS ARE EXPECTED TO
PREVAIL ACROSS ALL TAF SITES THROUGH 30/12Z. HOWEVER...PASSING
SHOWERS WILL AFFECT THE LOCAL TAF SITES FROM TIME TO TIME. LOW LEVEL
WINDS WILL BE MAINLY SOUTHEAST AT 10 KTS.

&&

.MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TONIGHT. DETERIORATING CONDITIONS
EXPECTED TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR
THUNDERSTORM DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF
THE REGIONAL WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

71/10





000
FXCA62 TJSJ 291627
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1227 PM AST FRI MAY 29 2015

.UPDATE...SHOWERS WITH THUNDERSTORMS STARTED TO DEVELOP ACROSS THE
CORDILLERA CENTRAL LATE THIS MORNING. THESE SHOWERS AND
THUNDERSTORMS WERE MOVING NORTH NORTHEAST...UNDER A SOUTH TO
SOUTH SOUTHWEST WIND FLOW. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP THIS AFTERNOON...AS DEEP TROPICAL MOISTURE CONTINUES TO
AFFECT THE LOCAL REGION. NO CHANGE MADE TO FORECAST GRIDS.

&&

.AVIATION...MVFR CONDITIONS ARE EXPECTED OVER THE TJMZ...TJBQ..AND
TJSJ THROUGH THE AFTERNOON HOURS. ELSEWHERE...VFR CONDITIONS ARE
EXPECTED.

&&

.MARINE...MARINE WEATHER STATEMENTS HAVE BEEN ISSUED DUE TO
CLUSTER OF THUNDERSTORMS ACROSS THE LOCAL WATERS. MARINERS CAN
EXPECTED STRONG GUSTY WIND AND FREQUENT LIGHTNING OVER THE LOCAL
WATERS FROM TIME TO TIME DUE TO THESE THUNDERSTORMS.


&&

.PREV DISCUSSION... /ISSUED 624 AM AST FRI MAY 29 2015/

SYNOPSIS...UPPER LOW WILL REMAIN TO THE NORTH OF THE LOCAL AREA
FOR THE NEXT FEW DAYS AS IT SLOWLY SHIFTS TO THE WEST...THEN AN
UPPER RIDGE WILL DOMINATE OVER THE LOCAL AREA BY TUESDAY. A
TROPICAL WAVE IS EXPECTED TO MOVE IN LATER TODAY AND INCREASE THE
AVAILABLE MOISTURE THROUGH THE WEEKEND ANS INTO EARLY NEXT WEEK.

DISCUSSION...A RATHER INTERESTING SETUP IS IN STORE FOR TODAY AND
INTO THE WEEKEND. AT THE TIME...CONFIDENCE IS MODERATE AS WE SEEM
TO HAVE SEVERAL QUESTIONS ABOUT THE IMPACT BE OF SUCH AS
SETUP...CONSIDER THE LACK OF RAINFALL THAT EASTERN PR AND THE USVI
HAS OBSERVED IN THE PAST SEVERAL MONTHS...THE TROPICAL WAVE MOVING
IN WITH THE UPPER LOW TO THE NORTH OF THE LOCAL AREA...THE HIGH
CLOUDS MOVING IN FROM THE SOUTH AND THE DISCREPANCY FROM THE
DIFFERENT MODEL SOLUTIONS FOR TODAY AND SATURDAY. HOWEVER...THE
MAIN FORECASTER CONSENSUS IS THAT AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED STARTING TODAY AND LASTING
THROUGH AT LEAST SUNDAY. OCCASIONAL STRONG THUNDERSTORMS WITH
LOCALLY HEAVY RAIN ARE EXPECTED THIS WEEKEND ACROSS DIFFERENT
SECTORS IN THE LOCAL FORECAST AREA. AT LEAST SOME URBAN AND SMALL
STREAM FLOODING IS EXPECTED WITH THE SHOWERS AND THUNDERSTORMS.

CURRENTLY WE HAVE AN UPPER LOW TO THE NORTH NORTHEAST OF THE LOCAL
ISLANDS AND THE TROPICAL WAVE MOVING IN FROM THE EAST. THE
AVAILABLE MOISTURE WILL INCREASE TODAY WITH PRECIPITABLE WATER
VALUES JUMPING TO ALMOST 2 INCHES BY THIS AFTERNOON. WHEN THIS
MOISTURE ADVECTION IS COMBINED WITH THE DAYTIME HEATING AND THE
LOCAL EFFECTS...SOME GOOD SHOWERS AND THUNDERSTORMS NORMALLY
DEVELOP ACROSS THE LOCAL AREA. HOWEVER...SATELLITE IR IS SHOWING
AN AREA OF HIGH CLOUDS MOVING INTO THE LOCAL AREA THIS MORNING BUT
THE RADAR HAS YET TO DETECT ANY SIGNIFICANT RAINFALL ASSOCIATED
WITH THE CLOUDINESS OVER THE LOCAL CARIBBEAN WATERS. HAVING SAID
THAT...THE GUADELOUPE RADAR DOES SHOW SOME SHOWER ACTIVITY AND THE
SHOWERS ARE MOVING RATHER FAST TO THE NORTH NORTHEAST. A FEW OF
THOSE SHOWERS LOOK MODERATE TO LOCALLY HEAVY. THIS CLOUDINESS IS
QUITE LARGE ANS MAY LINGER OVER PR AND THE USVI AT LEAST THROUGH
THE MORNING HOURS...WHICH WILL LIMIT SURFACE HEATING OVER THE
ISLANDS...LIMITING THE THUNDERSTORM DEVELOPMENT. HOWEVER...MODEL
GUIDANCE IS SHOWING SOME GOOD DIVERGENCE ALOFT THIS AFTERNOON
ACROSS THE LOCAL WATERS AND OVER PR AND THE USVI. THIS IS
BASICALLY THE OPPOSITE TO WHAT THE SAME MODEL HAS BEEN SAYING FOR
THE PAST 5 DAYS OR SO. UP UNTIL TODAY...THE GFS MODEL INDICATED
CONVERGENCE FOR TODAY IN THE UPPER LEVELS...STRONG DIVERGENCE
ALOFT WOULD BE CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT.
THE HI- RES MODELS SUCH AS THE WRF 2KM AND 6KM AND THE NMM ARE
SHOWING LITTLE TO NO SHOWER ACTIVITY TODAY OVER THE ISLANDS...THE
GFS SHOWS SOME ACTIVITY BUT THE ONLY MODEL THAT IS RATHER BULLISH
ON THE PRECIP IS THE ARW MODEL WHICH SHOWS A SIGNIFICANT AMOUNT OF
PRECIP ACROSS THE CARIBBEAN WATERS AND NW- PR...WITH SOME ISOLATED
AREAS OF PRECIP ELSEWHERE. OUR FORECAST WAS ADJUSTED SLIGHTLY BUT
IT STILL SHOWS A STEADY INCREASE OF SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE DAY WITH THE CARIBBEAN WATERS HAVING NUMEROUS
SHOWERS AND THE INTERIOR OF PR INTO NW-PR DEVELOPING SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ELSEWHERE.

SATURDAY STILL LOOKS LIKE A PRETTY ACTIVE DAY. HOWEVER...THE GFS
MODEL USED TO BE PRETTY CONSISTENT SHOWING UPPER LEVEL DIVERGENCE
THROUGH THE DAY SATURDAY...THE 29/00Z RUN STILL SHOWS THAT
DIVERGENCE ALOFT BUT DURING THE EVENING HOURS...WHILE THE 29/06Z
RUN ONCE AGAIN SHOWS THAT DIVERGENCE ALOFT DURING THE DAY AND THEN
LINGERING INTO THE EVENING. EITHER CASE...THE DIVERGENCE ALOFT IS
QUITE STRONG ACCORDING TO THE GFS MODEL...WITH AVAILABLE MOISTURE
STILL VERY GOOD WITH PRECIPITABLE WATER VALUES STILL HOVERING AT
AROUND 2 INCHES. THE NMM MODEL AND WRF ARE ALSO NOT LIKING THIS
SETUP VERY MUCH AND ARE SHOWING A RELATIVELY DRY SATURDAY...HOWEVER
THE ARW MODEL BRINGS IN A LOT OF SHOWERS AND THUNDERSTORMS TO THE
LOCAL ISLANDS...ESPECIALLY THE NORTHERN HALF OF PR AND THE USVI.
ACCORDING TO THE LATEST GFS MODEL THE AVAILABLE MOISTURE WILL BE
GOOD AND THE DIVERGENCE ALOFT WILL BE STRONG THROUGH AT LEAST
SUNDAY.

SO WE DO EXPECT A RATHER ACTIVE WEEKEND...EVEN WITH SOME OF THE
HI-RES MODELS INDICATING LITTLE TO NO PRECIP THESE NEXT FEW DAYS.
THE BIG PICTURE SETUP IS CONDUCIVE TO SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE LOCAL AREA...AT LEAST ON FRIDAY AND
SATURDAY...HOWEVER FORECAST SOUNDINGS SHOW A PROFILE MORE
CONSISTENT WITH HIGH CLOUDINESS BUT NOT AS MUCH PRECIP FOR SUNDAY
AND MONDAY.

THERE ARE QUESTIONS ON THE POTENTIAL IMPACT THE SHOWERS AND
THUNDERSTORMS WILL HAVE OVER THE ISLANDS. THE DISCREPANCY BETWEEN
THE GLOBAL AND THE HI-RES MODELS AND THE FACT THAT EASTERN PR IS
SO DRY...IT WAS DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH UNTIL
WE SAW HOW THE MODELS ARE HANDLING THIS PATTERN AND HOW MUCH RAIN
IT ACTUALLY FALLS TODAY ACROSS THE LOCAL ISLANDS. WE HAVE TO TAKE
INTO ACCOUNT NOT ONLY METEOROLOGICAL CONDITIONS BUT ALSO
HYDROLOGICAL CONDITIONS...AND RIGHT NOW THE HYDROLOGICAL
CONDITIONS ARE THAT THE RIVERS ARE RUNNING VERY LOW AND THE SOIL
ACROSS EASTERN PR IS IN NEED OF SOME WATER...IT WILL TAKE A LOT OF
RAIN TO CAUSE RIVER FLOODING ACROSS EASTERN PR...NOT SO MUCH FOR
THE WESTERN HALF OF PR WHICH HAS OVSERVED CONSISTENT RAINFALL FOR
THE PAST SEVERAL DAYS.

STAY TUNED FOR POSSIBLE CHANGES AS WE GATHER MORE INFORMATION ON
THIS EVENT TODAY.

WEATHER CONDITIONS ARE EXPECTED TO IMPROVE BY TUESDAY AND INTO THE
REST OF THE WEEK...WITH A MORE TYPICAL PATTERN OF MORNING SHOWERS
ACROSS THE WATERS AND AFTERNOON CONVECTION DUE TO LOCAL EFFECTS.

AVIATION...INCREASING SHRA AND TSRA EN ROUTE FROM THE
WINDWARD ISLANDS WILL AFFECT THE FLYING AREA OF TNCM AND TKPK THRU
THE FCST PERIOD...SPREADING THROUGH SOUTHEASTERN PR AND THE USVI BY
14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN HIGHER
TERRAIN AND NORTHWESTERN PR AFT 16Z. SE WINDS OF 10-15 KT EXPECTED
BELOW 5 KFT WITH HIGHER GUSTS NEAR TSRA...SW-W WINDS ABV/INCREASING
W/HEIGHT. UNSETTLED WEATHER CONDITIONS WILL CONTINUE THRU THE
WEEKEND.

MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TODAY. DETERIORATING CONDITIONS EXPECTED
TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF THE REGIONAL
WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

71/10




000
FXCA62 TJSJ 291627
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1227 PM AST FRI MAY 29 2015

.UPDATE...SHOWERS WITH THUNDERSTORMS STARTED TO DEVELOP ACROSS THE
CORDILLERA CENTRAL LATE THIS MORNING. THESE SHOWERS AND
THUNDERSTORMS WERE MOVING NORTH NORTHEAST...UNDER A SOUTH TO
SOUTH SOUTHWEST WIND FLOW. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO DEVELOP THIS AFTERNOON...AS DEEP TROPICAL MOISTURE CONTINUES TO
AFFECT THE LOCAL REGION. NO CHANGE MADE TO FORECAST GRIDS.

&&

.AVIATION...MVFR CONDITIONS ARE EXPECTED OVER THE TJMZ...TJBQ..AND
TJSJ THROUGH THE AFTERNOON HOURS. ELSEWHERE...VFR CONDITIONS ARE
EXPECTED.

&&

.MARINE...MARINE WEATHER STATEMENTS HAVE BEEN ISSUED DUE TO
CLUSTER OF THUNDERSTORMS ACROSS THE LOCAL WATERS. MARINERS CAN
EXPECTED STRONG GUSTY WIND AND FREQUENT LIGHTNING OVER THE LOCAL
WATERS FROM TIME TO TIME DUE TO THESE THUNDERSTORMS.


&&

.PREV DISCUSSION... /ISSUED 624 AM AST FRI MAY 29 2015/

SYNOPSIS...UPPER LOW WILL REMAIN TO THE NORTH OF THE LOCAL AREA
FOR THE NEXT FEW DAYS AS IT SLOWLY SHIFTS TO THE WEST...THEN AN
UPPER RIDGE WILL DOMINATE OVER THE LOCAL AREA BY TUESDAY. A
TROPICAL WAVE IS EXPECTED TO MOVE IN LATER TODAY AND INCREASE THE
AVAILABLE MOISTURE THROUGH THE WEEKEND ANS INTO EARLY NEXT WEEK.

DISCUSSION...A RATHER INTERESTING SETUP IS IN STORE FOR TODAY AND
INTO THE WEEKEND. AT THE TIME...CONFIDENCE IS MODERATE AS WE SEEM
TO HAVE SEVERAL QUESTIONS ABOUT THE IMPACT BE OF SUCH AS
SETUP...CONSIDER THE LACK OF RAINFALL THAT EASTERN PR AND THE USVI
HAS OBSERVED IN THE PAST SEVERAL MONTHS...THE TROPICAL WAVE MOVING
IN WITH THE UPPER LOW TO THE NORTH OF THE LOCAL AREA...THE HIGH
CLOUDS MOVING IN FROM THE SOUTH AND THE DISCREPANCY FROM THE
DIFFERENT MODEL SOLUTIONS FOR TODAY AND SATURDAY. HOWEVER...THE
MAIN FORECASTER CONSENSUS IS THAT AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED STARTING TODAY AND LASTING
THROUGH AT LEAST SUNDAY. OCCASIONAL STRONG THUNDERSTORMS WITH
LOCALLY HEAVY RAIN ARE EXPECTED THIS WEEKEND ACROSS DIFFERENT
SECTORS IN THE LOCAL FORECAST AREA. AT LEAST SOME URBAN AND SMALL
STREAM FLOODING IS EXPECTED WITH THE SHOWERS AND THUNDERSTORMS.

CURRENTLY WE HAVE AN UPPER LOW TO THE NORTH NORTHEAST OF THE LOCAL
ISLANDS AND THE TROPICAL WAVE MOVING IN FROM THE EAST. THE
AVAILABLE MOISTURE WILL INCREASE TODAY WITH PRECIPITABLE WATER
VALUES JUMPING TO ALMOST 2 INCHES BY THIS AFTERNOON. WHEN THIS
MOISTURE ADVECTION IS COMBINED WITH THE DAYTIME HEATING AND THE
LOCAL EFFECTS...SOME GOOD SHOWERS AND THUNDERSTORMS NORMALLY
DEVELOP ACROSS THE LOCAL AREA. HOWEVER...SATELLITE IR IS SHOWING
AN AREA OF HIGH CLOUDS MOVING INTO THE LOCAL AREA THIS MORNING BUT
THE RADAR HAS YET TO DETECT ANY SIGNIFICANT RAINFALL ASSOCIATED
WITH THE CLOUDINESS OVER THE LOCAL CARIBBEAN WATERS. HAVING SAID
THAT...THE GUADELOUPE RADAR DOES SHOW SOME SHOWER ACTIVITY AND THE
SHOWERS ARE MOVING RATHER FAST TO THE NORTH NORTHEAST. A FEW OF
THOSE SHOWERS LOOK MODERATE TO LOCALLY HEAVY. THIS CLOUDINESS IS
QUITE LARGE ANS MAY LINGER OVER PR AND THE USVI AT LEAST THROUGH
THE MORNING HOURS...WHICH WILL LIMIT SURFACE HEATING OVER THE
ISLANDS...LIMITING THE THUNDERSTORM DEVELOPMENT. HOWEVER...MODEL
GUIDANCE IS SHOWING SOME GOOD DIVERGENCE ALOFT THIS AFTERNOON
ACROSS THE LOCAL WATERS AND OVER PR AND THE USVI. THIS IS
BASICALLY THE OPPOSITE TO WHAT THE SAME MODEL HAS BEEN SAYING FOR
THE PAST 5 DAYS OR SO. UP UNTIL TODAY...THE GFS MODEL INDICATED
CONVERGENCE FOR TODAY IN THE UPPER LEVELS...STRONG DIVERGENCE
ALOFT WOULD BE CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT.
THE HI- RES MODELS SUCH AS THE WRF 2KM AND 6KM AND THE NMM ARE
SHOWING LITTLE TO NO SHOWER ACTIVITY TODAY OVER THE ISLANDS...THE
GFS SHOWS SOME ACTIVITY BUT THE ONLY MODEL THAT IS RATHER BULLISH
ON THE PRECIP IS THE ARW MODEL WHICH SHOWS A SIGNIFICANT AMOUNT OF
PRECIP ACROSS THE CARIBBEAN WATERS AND NW- PR...WITH SOME ISOLATED
AREAS OF PRECIP ELSEWHERE. OUR FORECAST WAS ADJUSTED SLIGHTLY BUT
IT STILL SHOWS A STEADY INCREASE OF SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE DAY WITH THE CARIBBEAN WATERS HAVING NUMEROUS
SHOWERS AND THE INTERIOR OF PR INTO NW-PR DEVELOPING SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ELSEWHERE.

SATURDAY STILL LOOKS LIKE A PRETTY ACTIVE DAY. HOWEVER...THE GFS
MODEL USED TO BE PRETTY CONSISTENT SHOWING UPPER LEVEL DIVERGENCE
THROUGH THE DAY SATURDAY...THE 29/00Z RUN STILL SHOWS THAT
DIVERGENCE ALOFT BUT DURING THE EVENING HOURS...WHILE THE 29/06Z
RUN ONCE AGAIN SHOWS THAT DIVERGENCE ALOFT DURING THE DAY AND THEN
LINGERING INTO THE EVENING. EITHER CASE...THE DIVERGENCE ALOFT IS
QUITE STRONG ACCORDING TO THE GFS MODEL...WITH AVAILABLE MOISTURE
STILL VERY GOOD WITH PRECIPITABLE WATER VALUES STILL HOVERING AT
AROUND 2 INCHES. THE NMM MODEL AND WRF ARE ALSO NOT LIKING THIS
SETUP VERY MUCH AND ARE SHOWING A RELATIVELY DRY SATURDAY...HOWEVER
THE ARW MODEL BRINGS IN A LOT OF SHOWERS AND THUNDERSTORMS TO THE
LOCAL ISLANDS...ESPECIALLY THE NORTHERN HALF OF PR AND THE USVI.
ACCORDING TO THE LATEST GFS MODEL THE AVAILABLE MOISTURE WILL BE
GOOD AND THE DIVERGENCE ALOFT WILL BE STRONG THROUGH AT LEAST
SUNDAY.

SO WE DO EXPECT A RATHER ACTIVE WEEKEND...EVEN WITH SOME OF THE
HI-RES MODELS INDICATING LITTLE TO NO PRECIP THESE NEXT FEW DAYS.
THE BIG PICTURE SETUP IS CONDUCIVE TO SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE LOCAL AREA...AT LEAST ON FRIDAY AND
SATURDAY...HOWEVER FORECAST SOUNDINGS SHOW A PROFILE MORE
CONSISTENT WITH HIGH CLOUDINESS BUT NOT AS MUCH PRECIP FOR SUNDAY
AND MONDAY.

THERE ARE QUESTIONS ON THE POTENTIAL IMPACT THE SHOWERS AND
THUNDERSTORMS WILL HAVE OVER THE ISLANDS. THE DISCREPANCY BETWEEN
THE GLOBAL AND THE HI-RES MODELS AND THE FACT THAT EASTERN PR IS
SO DRY...IT WAS DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH UNTIL
WE SAW HOW THE MODELS ARE HANDLING THIS PATTERN AND HOW MUCH RAIN
IT ACTUALLY FALLS TODAY ACROSS THE LOCAL ISLANDS. WE HAVE TO TAKE
INTO ACCOUNT NOT ONLY METEOROLOGICAL CONDITIONS BUT ALSO
HYDROLOGICAL CONDITIONS...AND RIGHT NOW THE HYDROLOGICAL
CONDITIONS ARE THAT THE RIVERS ARE RUNNING VERY LOW AND THE SOIL
ACROSS EASTERN PR IS IN NEED OF SOME WATER...IT WILL TAKE A LOT OF
RAIN TO CAUSE RIVER FLOODING ACROSS EASTERN PR...NOT SO MUCH FOR
THE WESTERN HALF OF PR WHICH HAS OVSERVED CONSISTENT RAINFALL FOR
THE PAST SEVERAL DAYS.

STAY TUNED FOR POSSIBLE CHANGES AS WE GATHER MORE INFORMATION ON
THIS EVENT TODAY.

WEATHER CONDITIONS ARE EXPECTED TO IMPROVE BY TUESDAY AND INTO THE
REST OF THE WEEK...WITH A MORE TYPICAL PATTERN OF MORNING SHOWERS
ACROSS THE WATERS AND AFTERNOON CONVECTION DUE TO LOCAL EFFECTS.

AVIATION...INCREASING SHRA AND TSRA EN ROUTE FROM THE
WINDWARD ISLANDS WILL AFFECT THE FLYING AREA OF TNCM AND TKPK THRU
THE FCST PERIOD...SPREADING THROUGH SOUTHEASTERN PR AND THE USVI BY
14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN HIGHER
TERRAIN AND NORTHWESTERN PR AFT 16Z. SE WINDS OF 10-15 KT EXPECTED
BELOW 5 KFT WITH HIGHER GUSTS NEAR TSRA...SW-W WINDS ABV/INCREASING
W/HEIGHT. UNSETTLED WEATHER CONDITIONS WILL CONTINUE THRU THE
WEEKEND.

MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TODAY. DETERIORATING CONDITIONS EXPECTED
TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF THE REGIONAL
WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

71/10





000
FXCA62 TJSJ 291024
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
624 AM AST FRI MAY 29 2015

.SYNOPSIS...UPPER LOW WILL REMAIN TO THE NORTH OF THE LOCAL AREA
FOR THE NEXT FEW DAYS AS IT SLOWLY SHIFTS TO THE WEST...THEN AN
UPPER RIDGE WILL DOMINATE OVER THE LOCAL AREA BY TUESDAY. A
TROPICAL WAVE IS EXPECTED TO MOVE IN LATER TODAY AND INCREASE THE
AVAILABLE MOISTURE THROUGH THE WEEKEND ANS INTO EARLY NEXT WEEK.

&&

.DISCUSSION...A RATHER INTERESTING SETUP IS IN STORE FOR TODAY AND
INTO THE WEEKEND. AT THE TIME...CONFIDENCE IS MODERATE AS WE SEEM
TO HAVE SEVERAL QUESTIONS ABOUT THE IMPACT BE OF SUCH AS
SETUP...CONSIDER THE LACK OF RAINFALL THAT EASTERN PR AND THE USVI
HAS OBSERVED IN THE PAST SEVERAL MONTHS...THE TROPICAL WAVE MOVING
IN WITH THE UPPER LOW TO THE NORTH OF THE LOCAL AREA...THE HIGH
CLOUDS MOVING IN FROM THE SOUTH AND THE DISCREPANCY FROM THE
DIFFERENT MODEL SOLUTIONS FOR TODAY AND SATURDAY. HOWEVER...THE
MAIN FORECASTER CONSENSUS IS THAT AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED STARTING TODAY AND LASTING
THROUGH AT LEAST SUNDAY. OCCASIONAL STRONG THUNDERSTORMS WITH
LOCALLY HEAVY RAIN ARE EXPECTED THIS WEEKEND ACROSS DIFFERENT
SECTORS IN THE LOCAL FORECAST AREA. AT LEAST SOME URBAN AND SMALL
STREAM FLOODING IS EXPECTED WITH THE SHOWERS AND THUNDERSTORMS.

CURRENTLY WE HAVE AN UPPER LOW TO THE NORTH NORTHEAST OF THE LOCAL
ISLANDS AND THE TROPICAL WAVE MOVING IN FROM THE EAST. THE
AVAILABLE MOISTURE WILL INCREASE TODAY WITH PRECIPITABLE WATER
VALUES JUMPING TO ALMOST 2 INCHES BY THIS AFTERNOON. WHEN THIS
MOISTURE ADVECTION IS COMBINED WITH THE DAYTIME HEATING AND THE
LOCAL EFFECTS...SOME GOOD SHOWERS AND THUNDERSTORMS NORMALLY
DEVELOP ACROSS THE LOCAL AREA. HOWEVER...SATELLITE IR IS SHOWING
AN AREA OF HIGH CLOUDS MOVING INTO THE LOCAL AREA THIS MORNING BUT
THE RADAR HAS YET TO DETECT ANY SIGNIFICANT RAINFALL ASSOCIATED
WITH THE CLOUDINESS OVER THE LOCAL CARIBBEAN WATERS. HAVING SAID
THAT...THE GUADELOUPE RADAR DOES SHOW SOME SHOWER ACTIVITY AND THE
SHOWERS ARE MOVING RATHER FAST TO THE NORTH NORTHEAST. A FEW OF
THOSE SHOWERS LOOK MODERATE TO LOCALLY HEAVY. THIS CLOUDINESS IS
QUITE LARGE ANS MAY LINGER OVER PR AND THE USVI AT LEAST THROUGH
THE MORNING HOURS...WHICH WILL LIMIT SURFACE HEATING OVER THE
ISLANDS...LIMITING THE THUNDERSTORM DEVELOPMENT. HOWEVER...MODEL
GUIDANCE IS SHOWING SOME GOOD DIVERGENCE ALOFT THIS AFTERNOON
ACROSS THE LOCAL WATERS AND OVER PR AND THE USVI. THIS IS
BASICALLY THE OPPOSITE TO WHAT THE SAME MODEL HAS BEEN SAYING FOR
THE PAST 5 DAYS OR SO. UP UNTIL TODAY...THE GFS MODEL INDICATED
CONVERGENCE FOR TODAY IN THE UPPER LEVELS...STRONG DIVERGENCE
ALOFT WOULD BE CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT.
THE HI- RES MODELS SUCH AS THE WRF 2KM AND 6KM AND THE NMM ARE
SHOWING LITTLE TO NO SHOWER ACTIVITY TODAY OVER THE ISLANDS...THE
GFS SHOWS SOME ACTIVITY BUT THE ONLY MODEL THAT IS RATHER BULLISH
ON THE PRECIP IS THE ARW MODEL WHICH SHOWS A SIGNIFICANT AMOUNT OF
PRECIP ACROSS THE CARIBBEAN WATERS AND NW- PR...WITH SOME ISOLATED
AREAS OF PRECIP ELSEWHERE. OUR FORECAST WAS ADJUSTED SLIGHTLY BUT
IT STILL SHOWS A STEADY INCREASE OF SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE DAY WITH THE CARIBBEAN WATERS HAVING NUMEROUS
SHOWERS AND THE INTERIOR OF PR INTO NW-PR DEVELOPING SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ELSEWHERE.

SATURDAY STILL LOOKS LIKE A PRETTY ACTIVE DAY. HOWEVER...THE GFS
MODEL USED TO BE PRETTY CONSISTENT SHOWING UPPER LEVEL DIVERGENCE
THROUGH THE DAY SATURDAY...THE 29/00Z RUN STILL SHOWS THAT
DIVERGENCE ALOFT BUT DURING THE EVENING HOURS...WHILE THE 29/06Z
RUN ONCE AGAIN SHOWS THAT DIVERGENCE ALOFT DURING THE DAY AND THEN
LINGERING INTO THE EVENING. EITHER CASE...THE DIVERGENCE ALOFT IS
QUITE STRONG ACCORDING TO THE GFS MODEL...WITH AVAILABLE MOISTURE
STILL VERY GOOD WITH PRECIPITABLE WATER VALUES STILL HOVERING AT
AROUND 2 INCHES. THE NMM MODEL AND WRF ARE ALSO NOT LIKING THIS
SETUP VERY MUCH AND ARE SHOWING A RELATIVELY DRY SATURDAY...HOWEVER
THE ARW MODEL BRINGS IN A LOT OF SHOWERS AND THUNDERSTORMS TO THE
LOCAL ISLANDS...ESPECIALLY THE NORTHERN HALF OF PR AND THE USVI.
ACCORDING TO THE LATEST GFS MODEL THE AVAILABLE MOISTURE WILL BE
GOOD AND THE DIVERGENCE ALOFT WILL BE STRONG THROUGH AT LEAST
SUNDAY.

SO WE DO EXPECT A RATHER ACTIVE WEEKEND...EVEN WITH SOME OF THE
HI-RES MODELS INDICATING LITTLE TO NO PRECIP THESE NEXT FEW DAYS.
THE BIG PICTURE SETUP IS CONDUCIVE TO SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE LOCAL AREA...AT LEAST ON FRIDAY AND
SATURDAY...HOWEVER FORECAST SOUNDINGS SHOW A PROFILE MORE
CONSISTENT WITH HIGH CLOUDINESS BUT NOT AS MUCH PRECIP FOR SUNDAY
AND MONDAY.

THERE ARE QUESTIONS ON THE POTENTIAL IMPACT THE SHOWERS AND
THUNDERSTORMS WILL HAVE OVER THE ISLANDS. THE DISCREPANCY BETWEEN
THE GLOBAL AND THE HI-RES MODELS AND THE FACT THAT EASTERN PR IS
SO DRY...IT WAS DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH UNTIL
WE SAW HOW THE MODELS ARE HANDLING THIS PATTERN AND HOW MUCH RAIN
IT ACTUALLY FALLS TODAY ACROSS THE LOCAL ISLANDS. WE HAVE TO TAKE
INTO ACCOUNT NOT ONLY METEOROLOGICAL CONDITIONS BUT ALSO
HYDROLOGICAL CONDITIONS...AND RIGHT NOW THE HYDROLOGICAL
CONDITIONS ARE THAT THE RIVERS ARE RUNNING VERY LOW AND THE SOIL
ACROSS EASTERN PR IS IN NEED OF SOME WATER...IT WILL TAKE A LOT OF
RAIN TO CAUSE RIVER FLOODING ACROSS EASTERN PR...NOT SO MUCH FOR
THE WESTERN HALF OF PR WHICH HAS OVSERVED CONSISTENT RAINFALL FOR
THE PAST SEVERAL DAYS.

STAY TUNED FOR POSSIBLE CHANGES AS WE GATHER MORE INFORMATION ON
THIS EVENT TODAY.

WEATHER CONDITIONS ARE EXPECTED TO IMPROVE BY TUESDAY AND INTO THE
REST OF THE WEEK...WITH A MORE TYPICAL PATTERN OF MORNING SHOWERS
ACROSS THE WATERS AND AFTERNOON CONVECTION DUE TO LOCAL EFFECTS.

&&

.AVIATION...INCREASING SHRA AND TSRA EN ROUTE FROM THE
WINDWARD ISLANDS WILL AFFECT THE FLYING AREA OF TNCM AND TKPK THRU
THE FCST PERIOD...SPREADING THROUGH SOUTHEASTERN PR AND THE USVI BY
14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN HIGHER
TERRAIN AND NORTHWESTERN PR AFT 16Z. SE WINDS OF 10-15 KT EXPECTED
BELOW 5 KFT WITH HIGHER GUSTS NEAR TSRA...SW-W WINDS ABV/INCREASING
W/HEIGHT. UNSETTLED WEATHER CONDITIONS WILL CONTINUE THRU THE
WEEKEND.


&&

.MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TODAY. DETERIORATING CONDITIONS EXPECTED
TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF THE REGIONAL
WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

13/25





000
FXCA62 TJSJ 291024
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
624 AM AST FRI MAY 29 2015

.SYNOPSIS...UPPER LOW WILL REMAIN TO THE NORTH OF THE LOCAL AREA
FOR THE NEXT FEW DAYS AS IT SLOWLY SHIFTS TO THE WEST...THEN AN
UPPER RIDGE WILL DOMINATE OVER THE LOCAL AREA BY TUESDAY. A
TROPICAL WAVE IS EXPECTED TO MOVE IN LATER TODAY AND INCREASE THE
AVAILABLE MOISTURE THROUGH THE WEEKEND ANS INTO EARLY NEXT WEEK.

&&

.DISCUSSION...A RATHER INTERESTING SETUP IS IN STORE FOR TODAY AND
INTO THE WEEKEND. AT THE TIME...CONFIDENCE IS MODERATE AS WE SEEM
TO HAVE SEVERAL QUESTIONS ABOUT THE IMPACT BE OF SUCH AS
SETUP...CONSIDER THE LACK OF RAINFALL THAT EASTERN PR AND THE USVI
HAS OBSERVED IN THE PAST SEVERAL MONTHS...THE TROPICAL WAVE MOVING
IN WITH THE UPPER LOW TO THE NORTH OF THE LOCAL AREA...THE HIGH
CLOUDS MOVING IN FROM THE SOUTH AND THE DISCREPANCY FROM THE
DIFFERENT MODEL SOLUTIONS FOR TODAY AND SATURDAY. HOWEVER...THE
MAIN FORECASTER CONSENSUS IS THAT AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED STARTING TODAY AND LASTING
THROUGH AT LEAST SUNDAY. OCCASIONAL STRONG THUNDERSTORMS WITH
LOCALLY HEAVY RAIN ARE EXPECTED THIS WEEKEND ACROSS DIFFERENT
SECTORS IN THE LOCAL FORECAST AREA. AT LEAST SOME URBAN AND SMALL
STREAM FLOODING IS EXPECTED WITH THE SHOWERS AND THUNDERSTORMS.

CURRENTLY WE HAVE AN UPPER LOW TO THE NORTH NORTHEAST OF THE LOCAL
ISLANDS AND THE TROPICAL WAVE MOVING IN FROM THE EAST. THE
AVAILABLE MOISTURE WILL INCREASE TODAY WITH PRECIPITABLE WATER
VALUES JUMPING TO ALMOST 2 INCHES BY THIS AFTERNOON. WHEN THIS
MOISTURE ADVECTION IS COMBINED WITH THE DAYTIME HEATING AND THE
LOCAL EFFECTS...SOME GOOD SHOWERS AND THUNDERSTORMS NORMALLY
DEVELOP ACROSS THE LOCAL AREA. HOWEVER...SATELLITE IR IS SHOWING
AN AREA OF HIGH CLOUDS MOVING INTO THE LOCAL AREA THIS MORNING BUT
THE RADAR HAS YET TO DETECT ANY SIGNIFICANT RAINFALL ASSOCIATED
WITH THE CLOUDINESS OVER THE LOCAL CARIBBEAN WATERS. HAVING SAID
THAT...THE GUADELOUPE RADAR DOES SHOW SOME SHOWER ACTIVITY AND THE
SHOWERS ARE MOVING RATHER FAST TO THE NORTH NORTHEAST. A FEW OF
THOSE SHOWERS LOOK MODERATE TO LOCALLY HEAVY. THIS CLOUDINESS IS
QUITE LARGE ANS MAY LINGER OVER PR AND THE USVI AT LEAST THROUGH
THE MORNING HOURS...WHICH WILL LIMIT SURFACE HEATING OVER THE
ISLANDS...LIMITING THE THUNDERSTORM DEVELOPMENT. HOWEVER...MODEL
GUIDANCE IS SHOWING SOME GOOD DIVERGENCE ALOFT THIS AFTERNOON
ACROSS THE LOCAL WATERS AND OVER PR AND THE USVI. THIS IS
BASICALLY THE OPPOSITE TO WHAT THE SAME MODEL HAS BEEN SAYING FOR
THE PAST 5 DAYS OR SO. UP UNTIL TODAY...THE GFS MODEL INDICATED
CONVERGENCE FOR TODAY IN THE UPPER LEVELS...STRONG DIVERGENCE
ALOFT WOULD BE CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT.
THE HI- RES MODELS SUCH AS THE WRF 2KM AND 6KM AND THE NMM ARE
SHOWING LITTLE TO NO SHOWER ACTIVITY TODAY OVER THE ISLANDS...THE
GFS SHOWS SOME ACTIVITY BUT THE ONLY MODEL THAT IS RATHER BULLISH
ON THE PRECIP IS THE ARW MODEL WHICH SHOWS A SIGNIFICANT AMOUNT OF
PRECIP ACROSS THE CARIBBEAN WATERS AND NW- PR...WITH SOME ISOLATED
AREAS OF PRECIP ELSEWHERE. OUR FORECAST WAS ADJUSTED SLIGHTLY BUT
IT STILL SHOWS A STEADY INCREASE OF SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE DAY WITH THE CARIBBEAN WATERS HAVING NUMEROUS
SHOWERS AND THE INTERIOR OF PR INTO NW-PR DEVELOPING SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ELSEWHERE.

SATURDAY STILL LOOKS LIKE A PRETTY ACTIVE DAY. HOWEVER...THE GFS
MODEL USED TO BE PRETTY CONSISTENT SHOWING UPPER LEVEL DIVERGENCE
THROUGH THE DAY SATURDAY...THE 29/00Z RUN STILL SHOWS THAT
DIVERGENCE ALOFT BUT DURING THE EVENING HOURS...WHILE THE 29/06Z
RUN ONCE AGAIN SHOWS THAT DIVERGENCE ALOFT DURING THE DAY AND THEN
LINGERING INTO THE EVENING. EITHER CASE...THE DIVERGENCE ALOFT IS
QUITE STRONG ACCORDING TO THE GFS MODEL...WITH AVAILABLE MOISTURE
STILL VERY GOOD WITH PRECIPITABLE WATER VALUES STILL HOVERING AT
AROUND 2 INCHES. THE NMM MODEL AND WRF ARE ALSO NOT LIKING THIS
SETUP VERY MUCH AND ARE SHOWING A RELATIVELY DRY SATURDAY...HOWEVER
THE ARW MODEL BRINGS IN A LOT OF SHOWERS AND THUNDERSTORMS TO THE
LOCAL ISLANDS...ESPECIALLY THE NORTHERN HALF OF PR AND THE USVI.
ACCORDING TO THE LATEST GFS MODEL THE AVAILABLE MOISTURE WILL BE
GOOD AND THE DIVERGENCE ALOFT WILL BE STRONG THROUGH AT LEAST
SUNDAY.

SO WE DO EXPECT A RATHER ACTIVE WEEKEND...EVEN WITH SOME OF THE
HI-RES MODELS INDICATING LITTLE TO NO PRECIP THESE NEXT FEW DAYS.
THE BIG PICTURE SETUP IS CONDUCIVE TO SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE LOCAL AREA...AT LEAST ON FRIDAY AND
SATURDAY...HOWEVER FORECAST SOUNDINGS SHOW A PROFILE MORE
CONSISTENT WITH HIGH CLOUDINESS BUT NOT AS MUCH PRECIP FOR SUNDAY
AND MONDAY.

THERE ARE QUESTIONS ON THE POTENTIAL IMPACT THE SHOWERS AND
THUNDERSTORMS WILL HAVE OVER THE ISLANDS. THE DISCREPANCY BETWEEN
THE GLOBAL AND THE HI-RES MODELS AND THE FACT THAT EASTERN PR IS
SO DRY...IT WAS DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH UNTIL
WE SAW HOW THE MODELS ARE HANDLING THIS PATTERN AND HOW MUCH RAIN
IT ACTUALLY FALLS TODAY ACROSS THE LOCAL ISLANDS. WE HAVE TO TAKE
INTO ACCOUNT NOT ONLY METEOROLOGICAL CONDITIONS BUT ALSO
HYDROLOGICAL CONDITIONS...AND RIGHT NOW THE HYDROLOGICAL
CONDITIONS ARE THAT THE RIVERS ARE RUNNING VERY LOW AND THE SOIL
ACROSS EASTERN PR IS IN NEED OF SOME WATER...IT WILL TAKE A LOT OF
RAIN TO CAUSE RIVER FLOODING ACROSS EASTERN PR...NOT SO MUCH FOR
THE WESTERN HALF OF PR WHICH HAS OVSERVED CONSISTENT RAINFALL FOR
THE PAST SEVERAL DAYS.

STAY TUNED FOR POSSIBLE CHANGES AS WE GATHER MORE INFORMATION ON
THIS EVENT TODAY.

WEATHER CONDITIONS ARE EXPECTED TO IMPROVE BY TUESDAY AND INTO THE
REST OF THE WEEK...WITH A MORE TYPICAL PATTERN OF MORNING SHOWERS
ACROSS THE WATERS AND AFTERNOON CONVECTION DUE TO LOCAL EFFECTS.

&&

.AVIATION...INCREASING SHRA AND TSRA EN ROUTE FROM THE
WINDWARD ISLANDS WILL AFFECT THE FLYING AREA OF TNCM AND TKPK THRU
THE FCST PERIOD...SPREADING THROUGH SOUTHEASTERN PR AND THE USVI BY
14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN HIGHER
TERRAIN AND NORTHWESTERN PR AFT 16Z. SE WINDS OF 10-15 KT EXPECTED
BELOW 5 KFT WITH HIGHER GUSTS NEAR TSRA...SW-W WINDS ABV/INCREASING
W/HEIGHT. UNSETTLED WEATHER CONDITIONS WILL CONTINUE THRU THE
WEEKEND.


&&

.MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TODAY. DETERIORATING CONDITIONS EXPECTED
TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF THE REGIONAL
WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

13/25




000
FXCA62 TJSJ 291024
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
624 AM AST FRI MAY 29 2015

.SYNOPSIS...UPPER LOW WILL REMAIN TO THE NORTH OF THE LOCAL AREA
FOR THE NEXT FEW DAYS AS IT SLOWLY SHIFTS TO THE WEST...THEN AN
UPPER RIDGE WILL DOMINATE OVER THE LOCAL AREA BY TUESDAY. A
TROPICAL WAVE IS EXPECTED TO MOVE IN LATER TODAY AND INCREASE THE
AVAILABLE MOISTURE THROUGH THE WEEKEND ANS INTO EARLY NEXT WEEK.

&&

.DISCUSSION...A RATHER INTERESTING SETUP IS IN STORE FOR TODAY AND
INTO THE WEEKEND. AT THE TIME...CONFIDENCE IS MODERATE AS WE SEEM
TO HAVE SEVERAL QUESTIONS ABOUT THE IMPACT BE OF SUCH AS
SETUP...CONSIDER THE LACK OF RAINFALL THAT EASTERN PR AND THE USVI
HAS OBSERVED IN THE PAST SEVERAL MONTHS...THE TROPICAL WAVE MOVING
IN WITH THE UPPER LOW TO THE NORTH OF THE LOCAL AREA...THE HIGH
CLOUDS MOVING IN FROM THE SOUTH AND THE DISCREPANCY FROM THE
DIFFERENT MODEL SOLUTIONS FOR TODAY AND SATURDAY. HOWEVER...THE
MAIN FORECASTER CONSENSUS IS THAT AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED STARTING TODAY AND LASTING
THROUGH AT LEAST SUNDAY. OCCASIONAL STRONG THUNDERSTORMS WITH
LOCALLY HEAVY RAIN ARE EXPECTED THIS WEEKEND ACROSS DIFFERENT
SECTORS IN THE LOCAL FORECAST AREA. AT LEAST SOME URBAN AND SMALL
STREAM FLOODING IS EXPECTED WITH THE SHOWERS AND THUNDERSTORMS.

CURRENTLY WE HAVE AN UPPER LOW TO THE NORTH NORTHEAST OF THE LOCAL
ISLANDS AND THE TROPICAL WAVE MOVING IN FROM THE EAST. THE
AVAILABLE MOISTURE WILL INCREASE TODAY WITH PRECIPITABLE WATER
VALUES JUMPING TO ALMOST 2 INCHES BY THIS AFTERNOON. WHEN THIS
MOISTURE ADVECTION IS COMBINED WITH THE DAYTIME HEATING AND THE
LOCAL EFFECTS...SOME GOOD SHOWERS AND THUNDERSTORMS NORMALLY
DEVELOP ACROSS THE LOCAL AREA. HOWEVER...SATELLITE IR IS SHOWING
AN AREA OF HIGH CLOUDS MOVING INTO THE LOCAL AREA THIS MORNING BUT
THE RADAR HAS YET TO DETECT ANY SIGNIFICANT RAINFALL ASSOCIATED
WITH THE CLOUDINESS OVER THE LOCAL CARIBBEAN WATERS. HAVING SAID
THAT...THE GUADELOUPE RADAR DOES SHOW SOME SHOWER ACTIVITY AND THE
SHOWERS ARE MOVING RATHER FAST TO THE NORTH NORTHEAST. A FEW OF
THOSE SHOWERS LOOK MODERATE TO LOCALLY HEAVY. THIS CLOUDINESS IS
QUITE LARGE ANS MAY LINGER OVER PR AND THE USVI AT LEAST THROUGH
THE MORNING HOURS...WHICH WILL LIMIT SURFACE HEATING OVER THE
ISLANDS...LIMITING THE THUNDERSTORM DEVELOPMENT. HOWEVER...MODEL
GUIDANCE IS SHOWING SOME GOOD DIVERGENCE ALOFT THIS AFTERNOON
ACROSS THE LOCAL WATERS AND OVER PR AND THE USVI. THIS IS
BASICALLY THE OPPOSITE TO WHAT THE SAME MODEL HAS BEEN SAYING FOR
THE PAST 5 DAYS OR SO. UP UNTIL TODAY...THE GFS MODEL INDICATED
CONVERGENCE FOR TODAY IN THE UPPER LEVELS...STRONG DIVERGENCE
ALOFT WOULD BE CONDUCIVE TO SHOWER AND THUNDERSTORM DEVELOPMENT.
THE HI- RES MODELS SUCH AS THE WRF 2KM AND 6KM AND THE NMM ARE
SHOWING LITTLE TO NO SHOWER ACTIVITY TODAY OVER THE ISLANDS...THE
GFS SHOWS SOME ACTIVITY BUT THE ONLY MODEL THAT IS RATHER BULLISH
ON THE PRECIP IS THE ARW MODEL WHICH SHOWS A SIGNIFICANT AMOUNT OF
PRECIP ACROSS THE CARIBBEAN WATERS AND NW- PR...WITH SOME ISOLATED
AREAS OF PRECIP ELSEWHERE. OUR FORECAST WAS ADJUSTED SLIGHTLY BUT
IT STILL SHOWS A STEADY INCREASE OF SHOWER AND THUNDERSTORM
ACTIVITY THROUGH THE DAY WITH THE CARIBBEAN WATERS HAVING NUMEROUS
SHOWERS AND THE INTERIOR OF PR INTO NW-PR DEVELOPING SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ELSEWHERE.

SATURDAY STILL LOOKS LIKE A PRETTY ACTIVE DAY. HOWEVER...THE GFS
MODEL USED TO BE PRETTY CONSISTENT SHOWING UPPER LEVEL DIVERGENCE
THROUGH THE DAY SATURDAY...THE 29/00Z RUN STILL SHOWS THAT
DIVERGENCE ALOFT BUT DURING THE EVENING HOURS...WHILE THE 29/06Z
RUN ONCE AGAIN SHOWS THAT DIVERGENCE ALOFT DURING THE DAY AND THEN
LINGERING INTO THE EVENING. EITHER CASE...THE DIVERGENCE ALOFT IS
QUITE STRONG ACCORDING TO THE GFS MODEL...WITH AVAILABLE MOISTURE
STILL VERY GOOD WITH PRECIPITABLE WATER VALUES STILL HOVERING AT
AROUND 2 INCHES. THE NMM MODEL AND WRF ARE ALSO NOT LIKING THIS
SETUP VERY MUCH AND ARE SHOWING A RELATIVELY DRY SATURDAY...HOWEVER
THE ARW MODEL BRINGS IN A LOT OF SHOWERS AND THUNDERSTORMS TO THE
LOCAL ISLANDS...ESPECIALLY THE NORTHERN HALF OF PR AND THE USVI.
ACCORDING TO THE LATEST GFS MODEL THE AVAILABLE MOISTURE WILL BE
GOOD AND THE DIVERGENCE ALOFT WILL BE STRONG THROUGH AT LEAST
SUNDAY.

SO WE DO EXPECT A RATHER ACTIVE WEEKEND...EVEN WITH SOME OF THE
HI-RES MODELS INDICATING LITTLE TO NO PRECIP THESE NEXT FEW DAYS.
THE BIG PICTURE SETUP IS CONDUCIVE TO SHOWER AND THUNDERSTORM
ACTIVITY ACROSS THE LOCAL AREA...AT LEAST ON FRIDAY AND
SATURDAY...HOWEVER FORECAST SOUNDINGS SHOW A PROFILE MORE
CONSISTENT WITH HIGH CLOUDINESS BUT NOT AS MUCH PRECIP FOR SUNDAY
AND MONDAY.

THERE ARE QUESTIONS ON THE POTENTIAL IMPACT THE SHOWERS AND
THUNDERSTORMS WILL HAVE OVER THE ISLANDS. THE DISCREPANCY BETWEEN
THE GLOBAL AND THE HI-RES MODELS AND THE FACT THAT EASTERN PR IS
SO DRY...IT WAS DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH UNTIL
WE SAW HOW THE MODELS ARE HANDLING THIS PATTERN AND HOW MUCH RAIN
IT ACTUALLY FALLS TODAY ACROSS THE LOCAL ISLANDS. WE HAVE TO TAKE
INTO ACCOUNT NOT ONLY METEOROLOGICAL CONDITIONS BUT ALSO
HYDROLOGICAL CONDITIONS...AND RIGHT NOW THE HYDROLOGICAL
CONDITIONS ARE THAT THE RIVERS ARE RUNNING VERY LOW AND THE SOIL
ACROSS EASTERN PR IS IN NEED OF SOME WATER...IT WILL TAKE A LOT OF
RAIN TO CAUSE RIVER FLOODING ACROSS EASTERN PR...NOT SO MUCH FOR
THE WESTERN HALF OF PR WHICH HAS OVSERVED CONSISTENT RAINFALL FOR
THE PAST SEVERAL DAYS.

STAY TUNED FOR POSSIBLE CHANGES AS WE GATHER MORE INFORMATION ON
THIS EVENT TODAY.

WEATHER CONDITIONS ARE EXPECTED TO IMPROVE BY TUESDAY AND INTO THE
REST OF THE WEEK...WITH A MORE TYPICAL PATTERN OF MORNING SHOWERS
ACROSS THE WATERS AND AFTERNOON CONVECTION DUE TO LOCAL EFFECTS.

&&

.AVIATION...INCREASING SHRA AND TSRA EN ROUTE FROM THE
WINDWARD ISLANDS WILL AFFECT THE FLYING AREA OF TNCM AND TKPK THRU
THE FCST PERIOD...SPREADING THROUGH SOUTHEASTERN PR AND THE USVI BY
14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN HIGHER
TERRAIN AND NORTHWESTERN PR AFT 16Z. SE WINDS OF 10-15 KT EXPECTED
BELOW 5 KFT WITH HIGHER GUSTS NEAR TSRA...SW-W WINDS ABV/INCREASING
W/HEIGHT. UNSETTLED WEATHER CONDITIONS WILL CONTINUE THRU THE
WEEKEND.


&&

.MARINE...WINDS AND SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10
KNOTS OR LESS RESPECTIVELY TODAY. DETERIORATING CONDITIONS EXPECTED
TONIGHT AND SATURDAY DUE TO INCREASED POTENTIAL FOR THUNDERSTORM
DEVELOPMENT AND INCLEMENT WEATHER ACROSS PORTIONS OF THE REGIONAL
WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  87  78  87  75 /  60  40  80  50
STT  84  77  86  76 /  50  50  70  60

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

13/25





000
FXCA62 TJSJ 290209
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1009 PM AST THU MAY 28 2015

.UPDATE...THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI BY FRIDAY AFTERNOON.
THIS PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM ACROSS THE
THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE ACROSS THE
AREA ON FRIDAY AND INTO THE UPCOMING WEEKEND. THIS FEATURE IS
SUPPORTED BY AN ELONGATED INVERTED LOW LEVEL TROUGH WITH AXIS NOW
ACROSS PUERTO RICO AND THE MONA PASSAGE. A TROPICAL WAVE ACCOMPANIED
BY A BROAD AREA OF ITCZ MOISTURE WILL CONTINUE WEST NORTHWEST AND
MOVE ACROSS THE EASTERN CARIBBEAN FRIDAY THROUGH SATURDAY. THE
COMBINATION OF THE AFOREMENTIONED FEATURES WILL CREATE A VERY
MOIST AND UNSTABLE ENVIRONMENT ACROSS THE FORECAST AREA BEGINNING
FRIDAY AND CONTINUING INTO THE WEEKEND...WITH MOST ACTIVE PERIOD
SO FAR EXPECTED TO BE LATE FRIDAY AND SATURDAY...AND POSSIBLY
CONTINUING INTO SUNDAY WHEN TRAILING MOISTURE WILL BE SUFFICIENT
FOR EARLY MORNING AND DAYTIME CONVECTION ACROSS THE ISLANDS.

ON FRIDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY LEAD
TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY ACROSS
PARTS OF THE NORTH CENTRAL AND WEST INTERIOR...THEN LATER ACROSS
PARTS OF THE SAN JUAN METRO AREA. NO CHANGES MADE TO THE INHERITED
FORECAST PACKAGE AT THIS TIME...AS THE SHORT TERM WX AND POPS
ALREADY SHOWED INCREASING CONVECTION ACROSS THE ISLANDS OVER THE
NEXT COUPLE OF DAYS.

ON SATURDAY...INCREASING UPPER LEVEL DIVERGENCE ALONG WITH LOW
LOW LEVEL CONVERGENCE AND DEEPER MOISTURE ADVECTION ACROSS THE
REGION SHOULD LEAD TO A FAIRLY ACTIVE WEATHER DAY IF THE WEATHER
UNFOLDS AS SUGGESTED BY LATEST MODEL GUIDANCE AND THE OVERALL
WEATHER PATTERN THAT HAS BEEN SETTING UP IN RECENT DAYS. WILL
CONTINUE TO CLOSELY MONITOR THE SITUATION...AND DEPENDING ON LATEST
MODEL GUIDANCE...IF NECESSARY ISSUE A FLASH FLOOD WATCH WITHIN
THE NEXT 24 HOURS. STAY TUNED.

&&

.AVIATION UPDATE...VFR CONDS EXPECTED TO PREVAIL THROUGH THE
OVERNIGHT HOURS AT ALL THE TAFS SITES...EXCEPT THE LEEWARD
TERMINALS. INCREASING SHRA AND TSRA ACTIVITY WILL AFFECT THE
VICINITY OF TNCM AND TKPK AFT 29/06Z AND SPREADING THROUGH PR BY
29/14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN
HIGHER TERRAIN AFT 28/16Z. SE WINDS OF 10-15 KT EXPECTED BELOW 3K
FT WITH HIGHER GUSTS NEAR TSRA. UNSETTLED WEATHER CONTINUES THRU
THE WEEKEND.

&&

.MARINE UPDATE...NO SIG CHG TO PREVIOUS DISCUSSION...WINDS AND
SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10 KNOTS OR LESS
RESPECTIVELY OVERNIGHT THROUGH EARLY FRIDAY. DETERIORATING
CONDITIONS STILL EXPECTED BY LATE FRIDAY AND SATURDAY DUE TO
INCREASED POTENTIAL FOR THUNDERSTORM DEVELOPMENT AND INCLEMENT
WEATHER ACROSS PORTIONS OF THE REGIONAL WATERS.

&&

.PREV DISCUSSION... /ISSUED 321 PM AST THU MAY 28 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  78  87 /  20  70  60  90
STT  77  84  77  86 /  40  70  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/09




000
FXCA62 TJSJ 290209
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1009 PM AST THU MAY 28 2015

.UPDATE...THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI BY FRIDAY AFTERNOON.
THIS PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM ACROSS THE
THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE ACROSS THE
AREA ON FRIDAY AND INTO THE UPCOMING WEEKEND. THIS FEATURE IS
SUPPORTED BY AN ELONGATED INVERTED LOW LEVEL TROUGH WITH AXIS NOW
ACROSS PUERTO RICO AND THE MONA PASSAGE. A TROPICAL WAVE ACCOMPANIED
BY A BROAD AREA OF ITCZ MOISTURE WILL CONTINUE WEST NORTHWEST AND
MOVE ACROSS THE EASTERN CARIBBEAN FRIDAY THROUGH SATURDAY. THE
COMBINATION OF THE AFOREMENTIONED FEATURES WILL CREATE A VERY
MOIST AND UNSTABLE ENVIRONMENT ACROSS THE FORECAST AREA BEGINNING
FRIDAY AND CONTINUING INTO THE WEEKEND...WITH MOST ACTIVE PERIOD
SO FAR EXPECTED TO BE LATE FRIDAY AND SATURDAY...AND POSSIBLY
CONTINUING INTO SUNDAY WHEN TRAILING MOISTURE WILL BE SUFFICIENT
FOR EARLY MORNING AND DAYTIME CONVECTION ACROSS THE ISLANDS.

ON FRIDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY LEAD
TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY ACROSS
PARTS OF THE NORTH CENTRAL AND WEST INTERIOR...THEN LATER ACROSS
PARTS OF THE SAN JUAN METRO AREA. NO CHANGES MADE TO THE INHERITED
FORECAST PACKAGE AT THIS TIME...AS THE SHORT TERM WX AND POPS
ALREADY SHOWED INCREASING CONVECTION ACROSS THE ISLANDS OVER THE
NEXT COUPLE OF DAYS.

ON SATURDAY...INCREASING UPPER LEVEL DIVERGENCE ALONG WITH LOW
LOW LEVEL CONVERGENCE AND DEEPER MOISTURE ADVECTION ACROSS THE
REGION SHOULD LEAD TO A FAIRLY ACTIVE WEATHER DAY IF THE WEATHER
UNFOLDS AS SUGGESTED BY LATEST MODEL GUIDANCE AND THE OVERALL
WEATHER PATTERN THAT HAS BEEN SETTING UP IN RECENT DAYS. WILL
CONTINUE TO CLOSELY MONITOR THE SITUATION...AND DEPENDING ON LATEST
MODEL GUIDANCE...IF NECESSARY ISSUE A FLASH FLOOD WATCH WITHIN
THE NEXT 24 HOURS. STAY TUNED.

&&

.AVIATION UPDATE...VFR CONDS EXPECTED TO PREVAIL THROUGH THE
OVERNIGHT HOURS AT ALL THE TAFS SITES...EXCEPT THE LEEWARD
TERMINALS. INCREASING SHRA AND TSRA ACTIVITY WILL AFFECT THE
VICINITY OF TNCM AND TKPK AFT 29/06Z AND SPREADING THROUGH PR BY
29/14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN
HIGHER TERRAIN AFT 28/16Z. SE WINDS OF 10-15 KT EXPECTED BELOW 3K
FT WITH HIGHER GUSTS NEAR TSRA. UNSETTLED WEATHER CONTINUES THRU
THE WEEKEND.

&&

.MARINE UPDATE...NO SIG CHG TO PREVIOUS DISCUSSION...WINDS AND
SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10 KNOTS OR LESS
RESPECTIVELY OVERNIGHT THROUGH EARLY FRIDAY. DETERIORATING
CONDITIONS STILL EXPECTED BY LATE FRIDAY AND SATURDAY DUE TO
INCREASED POTENTIAL FOR THUNDERSTORM DEVELOPMENT AND INCLEMENT
WEATHER ACROSS PORTIONS OF THE REGIONAL WATERS.

&&

.PREV DISCUSSION... /ISSUED 321 PM AST THU MAY 28 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  78  87 /  20  70  60  90
STT  77  84  77  86 /  40  70  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/09





000
FXCA62 TJSJ 290209
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1009 PM AST THU MAY 28 2015

.UPDATE...THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI BY FRIDAY AFTERNOON.
THIS PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM ACROSS THE
THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE ACROSS THE
AREA ON FRIDAY AND INTO THE UPCOMING WEEKEND. THIS FEATURE IS
SUPPORTED BY AN ELONGATED INVERTED LOW LEVEL TROUGH WITH AXIS NOW
ACROSS PUERTO RICO AND THE MONA PASSAGE. A TROPICAL WAVE ACCOMPANIED
BY A BROAD AREA OF ITCZ MOISTURE WILL CONTINUE WEST NORTHWEST AND
MOVE ACROSS THE EASTERN CARIBBEAN FRIDAY THROUGH SATURDAY. THE
COMBINATION OF THE AFOREMENTIONED FEATURES WILL CREATE A VERY
MOIST AND UNSTABLE ENVIRONMENT ACROSS THE FORECAST AREA BEGINNING
FRIDAY AND CONTINUING INTO THE WEEKEND...WITH MOST ACTIVE PERIOD
SO FAR EXPECTED TO BE LATE FRIDAY AND SATURDAY...AND POSSIBLY
CONTINUING INTO SUNDAY WHEN TRAILING MOISTURE WILL BE SUFFICIENT
FOR EARLY MORNING AND DAYTIME CONVECTION ACROSS THE ISLANDS.

ON FRIDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY LEAD
TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY ACROSS
PARTS OF THE NORTH CENTRAL AND WEST INTERIOR...THEN LATER ACROSS
PARTS OF THE SAN JUAN METRO AREA. NO CHANGES MADE TO THE INHERITED
FORECAST PACKAGE AT THIS TIME...AS THE SHORT TERM WX AND POPS
ALREADY SHOWED INCREASING CONVECTION ACROSS THE ISLANDS OVER THE
NEXT COUPLE OF DAYS.

ON SATURDAY...INCREASING UPPER LEVEL DIVERGENCE ALONG WITH LOW
LOW LEVEL CONVERGENCE AND DEEPER MOISTURE ADVECTION ACROSS THE
REGION SHOULD LEAD TO A FAIRLY ACTIVE WEATHER DAY IF THE WEATHER
UNFOLDS AS SUGGESTED BY LATEST MODEL GUIDANCE AND THE OVERALL
WEATHER PATTERN THAT HAS BEEN SETTING UP IN RECENT DAYS. WILL
CONTINUE TO CLOSELY MONITOR THE SITUATION...AND DEPENDING ON LATEST
MODEL GUIDANCE...IF NECESSARY ISSUE A FLASH FLOOD WATCH WITHIN
THE NEXT 24 HOURS. STAY TUNED.

&&

.AVIATION UPDATE...VFR CONDS EXPECTED TO PREVAIL THROUGH THE
OVERNIGHT HOURS AT ALL THE TAFS SITES...EXCEPT THE LEEWARD
TERMINALS. INCREASING SHRA AND TSRA ACTIVITY WILL AFFECT THE
VICINITY OF TNCM AND TKPK AFT 29/06Z AND SPREADING THROUGH PR BY
29/14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN
HIGHER TERRAIN AFT 28/16Z. SE WINDS OF 10-15 KT EXPECTED BELOW 3K
FT WITH HIGHER GUSTS NEAR TSRA. UNSETTLED WEATHER CONTINUES THRU
THE WEEKEND.

&&

.MARINE UPDATE...NO SIG CHG TO PREVIOUS DISCUSSION...WINDS AND
SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10 KNOTS OR LESS
RESPECTIVELY OVERNIGHT THROUGH EARLY FRIDAY. DETERIORATING
CONDITIONS STILL EXPECTED BY LATE FRIDAY AND SATURDAY DUE TO
INCREASED POTENTIAL FOR THUNDERSTORM DEVELOPMENT AND INCLEMENT
WEATHER ACROSS PORTIONS OF THE REGIONAL WATERS.

&&

.PREV DISCUSSION... /ISSUED 321 PM AST THU MAY 28 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  78  87 /  20  70  60  90
STT  77  84  77  86 /  40  70  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/09




000
FXCA62 TJSJ 290209
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1009 PM AST THU MAY 28 2015

.UPDATE...THE UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL CONTINUE
TO SHIFT WEST SOUTHWEST TO JUST NORTH OF HAITI BY FRIDAY AFTERNOON.
THIS PATTERN WILL MAINTAIN THE SUBTROPICAL JET STREAM ACROSS THE
THE REGION WHICH HELP TO LIFT DEEP TROPICAL MOISTURE ACROSS THE
AREA ON FRIDAY AND INTO THE UPCOMING WEEKEND. THIS FEATURE IS
SUPPORTED BY AN ELONGATED INVERTED LOW LEVEL TROUGH WITH AXIS NOW
ACROSS PUERTO RICO AND THE MONA PASSAGE. A TROPICAL WAVE ACCOMPANIED
BY A BROAD AREA OF ITCZ MOISTURE WILL CONTINUE WEST NORTHWEST AND
MOVE ACROSS THE EASTERN CARIBBEAN FRIDAY THROUGH SATURDAY. THE
COMBINATION OF THE AFOREMENTIONED FEATURES WILL CREATE A VERY
MOIST AND UNSTABLE ENVIRONMENT ACROSS THE FORECAST AREA BEGINNING
FRIDAY AND CONTINUING INTO THE WEEKEND...WITH MOST ACTIVE PERIOD
SO FAR EXPECTED TO BE LATE FRIDAY AND SATURDAY...AND POSSIBLY
CONTINUING INTO SUNDAY WHEN TRAILING MOISTURE WILL BE SUFFICIENT
FOR EARLY MORNING AND DAYTIME CONVECTION ACROSS THE ISLANDS.

ON FRIDAY EXPECT A COMBINATION OF DAYTIME HEATING AND DIVERGENCE
ALOFT TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS. THIS WILL
INCREASE THE POTENTIAL FOR STRONG THUNDERSTORMS AND EVENTUALLY LEAD
TO URBAN AND SMALL STREAM FLOODING IN SOME AREAS...ESPECIALLY ACROSS
PARTS OF THE NORTH CENTRAL AND WEST INTERIOR...THEN LATER ACROSS
PARTS OF THE SAN JUAN METRO AREA. NO CHANGES MADE TO THE INHERITED
FORECAST PACKAGE AT THIS TIME...AS THE SHORT TERM WX AND POPS
ALREADY SHOWED INCREASING CONVECTION ACROSS THE ISLANDS OVER THE
NEXT COUPLE OF DAYS.

ON SATURDAY...INCREASING UPPER LEVEL DIVERGENCE ALONG WITH LOW
LOW LEVEL CONVERGENCE AND DEEPER MOISTURE ADVECTION ACROSS THE
REGION SHOULD LEAD TO A FAIRLY ACTIVE WEATHER DAY IF THE WEATHER
UNFOLDS AS SUGGESTED BY LATEST MODEL GUIDANCE AND THE OVERALL
WEATHER PATTERN THAT HAS BEEN SETTING UP IN RECENT DAYS. WILL
CONTINUE TO CLOSELY MONITOR THE SITUATION...AND DEPENDING ON LATEST
MODEL GUIDANCE...IF NECESSARY ISSUE A FLASH FLOOD WATCH WITHIN
THE NEXT 24 HOURS. STAY TUNED.

&&

.AVIATION UPDATE...VFR CONDS EXPECTED TO PREVAIL THROUGH THE
OVERNIGHT HOURS AT ALL THE TAFS SITES...EXCEPT THE LEEWARD
TERMINALS. INCREASING SHRA AND TSRA ACTIVITY WILL AFFECT THE
VICINITY OF TNCM AND TKPK AFT 29/06Z AND SPREADING THROUGH PR BY
29/14Z. MVFR/IFR POSSIBLE AND WIDESPREAD OBSCURATIONS LIKELY IN
HIGHER TERRAIN AFT 28/16Z. SE WINDS OF 10-15 KT EXPECTED BELOW 3K
FT WITH HIGHER GUSTS NEAR TSRA. UNSETTLED WEATHER CONTINUES THRU
THE WEEKEND.

&&

.MARINE UPDATE...NO SIG CHG TO PREVIOUS DISCUSSION...WINDS AND
SEAS WILL CONTINUE AT 4 FEET OR LESS AND 10 KNOTS OR LESS
RESPECTIVELY OVERNIGHT THROUGH EARLY FRIDAY. DETERIORATING
CONDITIONS STILL EXPECTED BY LATE FRIDAY AND SATURDAY DUE TO
INCREASED POTENTIAL FOR THUNDERSTORM DEVELOPMENT AND INCLEMENT
WEATHER ACROSS PORTIONS OF THE REGIONAL WATERS.

&&

.PREV DISCUSSION... /ISSUED 321 PM AST THU MAY 28 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  78  87 /  20  70  60  90
STT  77  84  77  86 /  40  70  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/09





000
FXCA62 TJSJ 281921
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
321 PM AST THU MAY 28 2015

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

&&

.DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

&&

.AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

&&

.MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  87  75 /  20  20  70  60
STT  86  77  84  77 /  20  40  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12




000
FXCA62 TJSJ 281921
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
321 PM AST THU MAY 28 2015

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NORTH OF THE AREA WILL
WEAKEN AND DRIFT NORTH NORTHEAST THROUGH THE WEEKEND. A BRANCH OF
THE SUBTROPICAL JET WILL CROSS OVER THE AREA FRIDAY MORNING AND
CONTINUE MOVING NORTH AS HIGH PRESSURE BUILDS OVER THE EASTERN
CARIBBEAN. HIGH PRESSURE WILL SPREAD INTO THE WESTERN CARIBBEAN
AND INTENSIFY THROUGH THURSDAY WITH A STRONG RIDGE EXTENDING
NORTH.

AT MID LEVELS...LOW PRESSURE NORTH OF THE AREA WILL DRIFT NORTH AS
HIGH PRESSURE EXTENDS WESTWARD OVER THE CARIBBEAN SEA THROUGH MID
WEEK. HIGH PRESSURE DOMINATES THE CARIBBEAN SEA THROUGH THE
REMAINDER OF NEXT WEEK. MOISTURE WILL INCREASE SIGNIFICANTLY
BEGINNING ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE EAST OF THE BAHAMAS NORTH OF THE
AREA WILL DRIFT EAST AND WEAKEN LEAVING MODERATELY STRONG HIGH
PRESSURE OVER THE CENTRAL ATLANTIC AND MODERATE TO FRESH EAST
SOUTHEAST TRADE WINDS OVER THE LOCAL AREA BY SUNDAY. DURING THE
WEEK THE HIGH WILL PULL NORTHEAST AND GRADIENTS WILL
WEAKEN...ALLOWING WINDS TO DIMINISH AND TURN TO THE SOUTHEAST.
MUCH BETTER MOISTURE WILL MOVE INTO THE AREA ON FRIDAY FROM THE
SOUTHEAST AND CONTINUE AT HIGHER LEVELS THROUGH THE ENTIRE WEEK
AHEAD.

&&

.DISCUSSION...MOISTURE THIS MORNING AT 12Z WAS SIMILAR TO THAT
YESTERDAY AT 27/12Z...BUT WINDS BELOW 7500 FEET TURNED
DEFINITIVELY TO THE SOUTHEAST AND CONVECTION WAS NOT QUITE AS
QUICK TO FORM. SOME THUNDERSHOWERS WITH HEAVY RAIN DID APPEAR FROM
ANASCO TO VEGA ALTA. VEGA BAJA REPORTED ABOUT 6 TENTHS OF AN INCH
OF RAIN WITH SOME SMALL HAIL WITH HIGHER AMOUNTS POSSIBLE TO THE
NORTH. MOISTURE CAUSED CLOUDY SKIES IN THE BARBADOS THIS MORNING
AND SKIES CLOUDED UP IN SANTA LUCIA AND GUADELOUPE DURING THE DAY
WITH SHOWERS IN THE AREA...CONFIRMING WHAT MIMIC AND THE MODELS
ALREADY TOLD US...THAT DEEP MOISTURE IS HEADED TOWARD THE AREA.
THE GFS SUGGESTS THAT THE DRIEST AIR WILL PASS OVERHEAD AROUND
29/06Z FOLLOWED ABRUPTLY BY AIR WITH COLUMNAR MOISTURE OF OVER 1.8
INCHES ARRIVING BY 28/12Z. ALTHOUGH THE MODEL SENDS THE BEST
MOISTURE INTO THE DOMINICAN REPUBLIC AND OVER THE LOCAL OUTER
CARIBBEAN WATERS...THERE STILL APPEARS TO BE PLENTY OF MOISTURE
FOR SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY FRIDAY FOR
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THESE SHOWERS AND SOME
THUNDERSTORMS WILL LINGER WELL INTO THE NIGHT WITH GENERAL AMOUNTS
IN THE NEXT 24 TO 29 HOURS RANGING FROM 1 TO 3 INCHES IN THE
WETTER AREAS. SOME AREAS MAY RECEIVE LESS THAN ONE HALF INCH
DURING THE SAME TIME PERIOD. THEN ON SATURDAY MOISTURE WILL
INCREASE AND BETTER RAINFALL IS EXPECTED OVER A WIDER AREA.

A DECISION ON WHETHER TO ISSUE A WATCH WILL BE MADE NO LATER THAN
FRIDAY MORNING...IF NEEDED...AND CURRENT FORECASTS SUGGEST THAT
FLASH FLOODING ON SMALL RIVERS AND URBAN AND SMALL STREAM FLOODING
ARE LIKELY IN A FEW SPOTS AND POSSIBLE IN MORE THAN JUST A FEW
AREAS. CURRENTLY MODELS SUGGEST THAT THE U.S. VIRGIN ISLANDS WILL
HAVE A SIGNIFICANT AMOUNT OF RAINFALL WILL OCCUR THERE FRIDAY
THROUGH SUNDAY. SHOWERS WILL CONTINUE THROUGH AT LEAST
MONDAY...ALTHOUGH THE BEST MOISTURE APPEARS TO OCCUR SATURDAY
EVENING OVER THE FORECAST AREA AND SUBSIDES SLOWLY OVER THE
FORECAST AREA THROUGH WEDNESDAY. MOISTURE WILL INCREASE SOMEWHAT
THURSDAY NIGHT THROUGH FRIDAY NEXT WEEK.

&&

.AVIATION...BETWEEN 28/17Z AND 28/23Z...MVFR PSBL...MAINLY ACROSS
TJBQ AND TJMZ DUE TO AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS
THE INTERIOR...WEST AND NW QUADRANT OF PR. SFC WINDS FROM THE
E-ESE AT 10 TO 15 KT WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS
THROUGH 28/23Z... FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT
THEREAFTER. INCREASING SHOWERS AND THUNDERSTORMS BEGINNING NOW IN
TNCM AND TKPK AND SPREADING THROUGH 28/14Z TO PR AND USVI.
WIDESPREAD OBSCURATIONS OF HIGHER TERRAIN AFT 28/16Z.

&&

.MARINE...WINDS AND SEAS INCREASE FRIDAY NIGHT THROUGH SATURDAY
NIGHT WITH SHOWERS AND THUNDERSTORMS INCREASING OVER THE AREA.
CONDITIONS ARE NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
LEVELS...BUT LOCAL GUSTY WINDS IN EXCESS OF 30 KNOTS COULD BE
ENCOUNTERED IN THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  87  75 /  20  20  70  60
STT  86  77  84  77 /  20  40  70  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12





000
FXCA62 TJSJ 281449
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1049 AM AST THU MAY 28 2015

.UPDATE...BRIEF PASSING SHOWERS WERE DETECTED ACROSS THE LAND
AREAS...HOWEVER MOST OF THE SHOWER ACTIVITY HAVE BEEN OBSERVED
OVER THE LOCAL WATERS THIS MORNING. MOSTLY SUNNY TO PARTLY CLOUDY
SKIES PREVAILED ACROSS THE LOCAL ISLANDS TODAY. AFTER 8 AM AST
CLOUDINESS STARTED TO INCREASE OVER THE SOUTHERN SLOPES OF THE
CORDILLERA CENTRAL OF PUERTO RICO...ST CROIX...ST THOMAS...
VIEQUES AND CULEBRA. THE FORECAST PACKAGE STILL THE SAME THAT WE
RECEIVED THIS MORNING.

A SIMILAR PATTERN IS EXPECTED FOR THIS AFTERNOON...BUT THIS TIME
DUE TO THE EAST-SOUTHEASTERLY WIND FLOW...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED ACROSS THE INTERIOR...WEST AND
NORTHWESTERN SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LEVEL LOW...NORTHEAST OF PUERTO RICO...
BY FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.


&&

.AVIATION...VFR CONDS EXPECTED TO PREVAIL DURING THE MORNING HRS WITH
VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. BETWEEN 28/17Z
AND 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS THE INTERIOR...WEST
AND NW QUADRANT OF PR. SFC WINDS FROM THE E-ESE AT 10 TO 15 KT
WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS THROUGH 28/23Z...
FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT THEREAFTER.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS. WEATHER
CONDITIONS ARE EXPECTED TO DETERIORATE DURING THE WEEKEND...STAY
TUNED FOR MORE INFO.

&&

.PREV DISCUSSION... /ISSUED 408 AM AST THU MAY 28 2015/

DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12





000
FXCA62 TJSJ 281449
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1049 AM AST THU MAY 28 2015

.UPDATE...BRIEF PASSING SHOWERS WERE DETECTED ACROSS THE LAND
AREAS...HOWEVER MOST OF THE SHOWER ACTIVITY HAVE BEEN OBSERVED
OVER THE LOCAL WATERS THIS MORNING. MOSTLY SUNNY TO PARTLY CLOUDY
SKIES PREVAILED ACROSS THE LOCAL ISLANDS TODAY. AFTER 8 AM AST
CLOUDINESS STARTED TO INCREASE OVER THE SOUTHERN SLOPES OF THE
CORDILLERA CENTRAL OF PUERTO RICO...ST CROIX...ST THOMAS...
VIEQUES AND CULEBRA. THE FORECAST PACKAGE STILL THE SAME THAT WE
RECEIVED THIS MORNING.

A SIMILAR PATTERN IS EXPECTED FOR THIS AFTERNOON...BUT THIS TIME
DUE TO THE EAST-SOUTHEASTERLY WIND FLOW...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED ACROSS THE INTERIOR...WEST AND
NORTHWESTERN SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LEVEL LOW...NORTHEAST OF PUERTO RICO...
BY FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.


&&

.AVIATION...VFR CONDS EXPECTED TO PREVAIL DURING THE MORNING HRS WITH
VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. BETWEEN 28/17Z
AND 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS THE INTERIOR...WEST
AND NW QUADRANT OF PR. SFC WINDS FROM THE E-ESE AT 10 TO 15 KT
WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS THROUGH 28/23Z...
FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT THEREAFTER.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS. WEATHER
CONDITIONS ARE EXPECTED TO DETERIORATE DURING THE WEEKEND...STAY
TUNED FOR MORE INFO.

&&

.PREV DISCUSSION... /ISSUED 408 AM AST THU MAY 28 2015/

DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12




000
FXCA62 TJSJ 281449
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1049 AM AST THU MAY 28 2015

.UPDATE...BRIEF PASSING SHOWERS WERE DETECTED ACROSS THE LAND
AREAS...HOWEVER MOST OF THE SHOWER ACTIVITY HAVE BEEN OBSERVED
OVER THE LOCAL WATERS THIS MORNING. MOSTLY SUNNY TO PARTLY CLOUDY
SKIES PREVAILED ACROSS THE LOCAL ISLANDS TODAY. AFTER 8 AM AST
CLOUDINESS STARTED TO INCREASE OVER THE SOUTHERN SLOPES OF THE
CORDILLERA CENTRAL OF PUERTO RICO...ST CROIX...ST THOMAS...
VIEQUES AND CULEBRA. THE FORECAST PACKAGE STILL THE SAME THAT WE
RECEIVED THIS MORNING.

A SIMILAR PATTERN IS EXPECTED FOR THIS AFTERNOON...BUT THIS TIME
DUE TO THE EAST-SOUTHEASTERLY WIND FLOW...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED ACROSS THE INTERIOR...WEST AND
NORTHWESTERN SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LEVEL LOW...NORTHEAST OF PUERTO RICO...
BY FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.


&&

.AVIATION...VFR CONDS EXPECTED TO PREVAIL DURING THE MORNING HRS WITH
VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. BETWEEN 28/17Z
AND 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS THE INTERIOR...WEST
AND NW QUADRANT OF PR. SFC WINDS FROM THE E-ESE AT 10 TO 15 KT
WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS THROUGH 28/23Z...
FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT THEREAFTER.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS. WEATHER
CONDITIONS ARE EXPECTED TO DETERIORATE DURING THE WEEKEND...STAY
TUNED FOR MORE INFO.

&&

.PREV DISCUSSION... /ISSUED 408 AM AST THU MAY 28 2015/

DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12




000
FXCA62 TJSJ 281449
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1049 AM AST THU MAY 28 2015

.UPDATE...BRIEF PASSING SHOWERS WERE DETECTED ACROSS THE LAND
AREAS...HOWEVER MOST OF THE SHOWER ACTIVITY HAVE BEEN OBSERVED
OVER THE LOCAL WATERS THIS MORNING. MOSTLY SUNNY TO PARTLY CLOUDY
SKIES PREVAILED ACROSS THE LOCAL ISLANDS TODAY. AFTER 8 AM AST
CLOUDINESS STARTED TO INCREASE OVER THE SOUTHERN SLOPES OF THE
CORDILLERA CENTRAL OF PUERTO RICO...ST CROIX...ST THOMAS...
VIEQUES AND CULEBRA. THE FORECAST PACKAGE STILL THE SAME THAT WE
RECEIVED THIS MORNING.

A SIMILAR PATTERN IS EXPECTED FOR THIS AFTERNOON...BUT THIS TIME
DUE TO THE EAST-SOUTHEASTERLY WIND FLOW...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED ACROSS THE INTERIOR...WEST AND
NORTHWESTERN SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LEVEL LOW...NORTHEAST OF PUERTO RICO...
BY FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.


&&

.AVIATION...VFR CONDS EXPECTED TO PREVAIL DURING THE MORNING HRS WITH
VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. BETWEEN 28/17Z
AND 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION AND MOUNTAIN OBSC ACROSS THE INTERIOR...WEST
AND NW QUADRANT OF PR. SFC WINDS FROM THE E-ESE AT 10 TO 15 KT
WITH HIGHER GUSTS AND SEA BREEZE VARIATIONS THROUGH 28/23Z...
FOLLOWED BY LIGHT SFC WINDS AT AROUND 5KT THEREAFTER.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS. WEATHER
CONDITIONS ARE EXPECTED TO DETERIORATE DURING THE WEEKEND...STAY
TUNED FOR MORE INFO.

&&

.PREV DISCUSSION... /ISSUED 408 AM AST THU MAY 28 2015/

DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

27/12





000
FXCA62 TJSJ 280808
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
408 AM AST THU MAY 28 2015

.DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

&&

.MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

25/54




000
FXCA62 TJSJ 280808
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
408 AM AST THU MAY 28 2015

.DISCUSSION...SOUTHERLY FLOW HAS ALREADY BEGUN ABOVE 850 MB ACROSS
THE EASTERN CARIBBEAN WHERE TROPICAL MOISTURE IS SURGING NORTHWEST.
THE FLOW WILL TURN MORE SOUTHEASTERLY BY TONIGHT WHICH WILL PUSH
THE HIGHEST MOISTURE MORE TOWARDS HISPANIOLA. ALL MODELS SHOW
PRECIPITABLE WATER OVER PR PAST 2 INCHES BY FRI MORNING...EXCEPT
THE NAM WHICH HOLDS OFF UNTIL LATE FRI NIGHT. BUT EVEN NAM SHOWS
GOOD RAINFALL AMOUNTS ON FRI AFTERNOON SO HAVE CONSERVATIVELY
PUSHED PROBABILITY OF RAINFALL INTO LIKELY CATEGORY FOR NORTHERN
PR WESTWARD FROM SAN JUAN FOR FRI AND SAT AFTERNOONS. GFS ALSO
SHOWS SOME 250 MB DIVERGENCE ON FRI WHICH COULD HELP DEVELOPMENT
BUT THE MODEL IS NOT VERY GOOD AT LOCATING THIS PARAMETER. THE
OTHER MAIN CAVEAT APPEARS TO BE THE AMOUNT OF HIGH CLOUDS WE MAY
HAVE WHICH WOULD REDUCE HEATING AND AFTERNOON CONVECTION. MODEL
SOUNDINGS SUGGEST PERSISTENT HIGH CLOUDS BUT IS LIKELY OVERDONE.
GFS SUGGESTS KEEPING PRECIPITABLE WATER IN THE VICINITY OF 2
INCHES ALMOST ALL OF NEXT WEEK AND COULD BE A GOOD WEEK FOR RAIN
ACROSS THE ISLANDS.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS THROUGH
28/17Z WITH VCSH DUE TO QUICK SHOWERS ACROSS THE LOCAL AREA. FROM
28/17Z TO 28/23Z...MVFR PSBL MAINLY ACROSS TJBQ AND TJMZ DUE TO
AFTERNOON CONVECTION ACROSS THE NW QUADRANT OF PR. SFC WINDS WILL
REMAIN LIGHT AT AROUND 5KT THROUGH 28/13Z...BECOMING E-ESE AT AROUND
10KT WITH SEA BREEZE VARIATIONS THEREAFTER.

&&

.MARINE...GENTLE TO MODERATE TRADES WILL CONTINUE THROUGH FRIDAY
BUT INCREASE A LITTLE INTO THE WEEKEND. SHOWERS AND THUNDERSTORMS
WILL ALSO INCREASE BEGINNING ON FRIDAY AS TROPICAL MOISTURE
ARRIVES FROM THE SOUTHEAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  78  89  76 /  20  20  60  50
STT  86  77  86  78 /  20  40  40  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

25/54





000
FXCA62 TJSJ 280300
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1100 PM AST WED MAY 27 2015

.UPDATE...
VARIABLY TO MOSTLY CLOUDY SKIES WERE OBSERVED ACROSS THE ISLANDS
LATE THIS AFTERNOON AND INTO THE EVENING HOURS. SCATTERED SHOWERS
WERE DETECTED WITH THE DOPPLER RADAR ACROSS THE INTERIOR...WESTERN...
SOUTHEASTERN SECTIONS OF THE ISLANDS. THE HEAVIEST SHOWER ACTIVITY
OCCURRED UNTIL AROUND 8:00 PM AST THIS EVENING. SEVERAL URBAN AND
SMALL STREAM FLOOD ADVISORIES WERE ISSUED FOR RAPID RAISES OF
RIVERS AND SMALL STREAM...AS WELL AS FOR URBAN AND MINOR FLOODING
ACROSS THE MUNICIPALITIES OF ADJUNTAS...PENUELAS...YAUCO...GUAYANILLA
AND UTUADO. WINDS WERE MAINLY FROM THE EAST NORTHEAST AT AROUND 10-15
MPH WITH HIGHER GUSTS AROUND THE SHOWER AND THUNDERSTORM ACTIVITY.

A SIMILAR PATTERN IS EXPECTED ON THURSDAY...WITH MORNING SHOWERS
ACROSS THE U.S. VIRGIN ISLANDS AND THE EASTERN PORTIONS OF PUERTO
RICO FOLLOWED BY AFTERNOON CONVECTION...WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE INTERIOR...WEST AND NORTHWESTERN
SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LOW...NORTHEAST OF PUERTO RICO...BY
FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS DURG MOST OF
PRD. SCT-BKN CLD LYRS NR FL020...FL050..FL120 DUE TO AFTN CONVECTION
TIL 28/04Z DSPTNG CLD COVER THEREAFTER...ISOLD PASSING SHRA EN ROUTE
BTW ISLANDS AND N OF PR FEW TOPS 140-180.  FM 28/17Z-28/22Z...MVFR
PSBL DUE TO AFTN CONVECTION OVR THE CENTRAL MTN RANGE OF PR AND ALSO
NW PORTIONS OF ISLANDS VCTY TJBQ AND TJMZ. WINDS BELOW 6K FT FM NE
AROUND 10 KT...BCMG FM W AND INCR W/HT ABV..MAX WND 50 KTS BTW FL400-
FL450 DURG PRD.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS.

&&

.PREV DISCUSSION... /ISSUED 330 PM AST WED MAY 27 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE ALONG 60 NORTH EAST OF
FLORIDA WILL MOVE NORTHWARD AND REJOIN THE FLOW. THE SUB TROPICAL
JET WILL PULL NORTH OVER THE AREA THURSDAY NIGHT AND FRIDAY THEN HIGH
PRESSURE WILL BUILD OVER THE EASTERN CARIBBEAN OVER THE WEEKEND.
THIS RIDGE WILL SHIFT SLOWLY TOWARD THE WINDWARD PASSAGE DURING
THE UPCOMING WEEK.

AT MID LEVELS...LOW PRESSURE NORTHEAST OF PUERTO RICO WILL PULL
NORTH AND WEAKEN OVER THE WEEKEND THEN HIGH PRESSURE WILL FILL IN
OVER THE EASTERN CARIBBEAN. VERY DRY MID LEVELS WILL GIVE WAY TO A
LARGE AREA OF MOISTURE ON FRIDAY. THIS MOISTURE WILL WEAKEN ON
TUESDAY BUT WILL NOT GET VERY FAR AWAY.

AT LOWER LEVELS...ALTHOUGH HIGH PRESSURE DOMINATES THE CENTRAL
ATLANTIC...VERY WEAK LOWS AND WEAK GRADIENTS ARE FOUND JUST NORTH
AND NORTHEAST OF THE FORECAST AREA. THESE WILL SHIFT WEST AND
FLOW WILL CONTINUE FROM THE SOUTHEAST. TROUGHINESS TO THE WEST AND
THE SOUTHEAST FLOW WILL CONTINUE THROUGH THE UPCOMING WEEK.

DISCUSSION...SHOWERS FORMED MID MORNING AROUND THE U.S. VIRGIN
ISLANDS AND OVER EASTERN PUERTO RICO...BUT HEAVY SHOWERS ERUPTED
QUICKLY JUST AFTER NOON OVER PUERTO RICO...BEING FUELED BY
INTENSE HEATING UNDER THE PREVIOUS SUNNY SKIES. THESE SHOWERS
CONTINUE TO PRODUCE HEAVY RAIN IN THE CENTRAL PORTION OF THE
ISLAND.

THE GFS CONTINUES TO SHOW RELATIVELY DRY AIR OVER THE AREA UNTIL
FRIDAY MORNING THEN MOISTURE INCREASES SHARPLY. ALTHOUGH THE
MOISTURE COLUMN FORECAST FOR THE WEEKEND IS NOT QUITE AS DEEP AS
WAS PREVIOUSLY FORECAST EARLIER THIS WEEK...VALUES STILL HOLD
BETWEEN 1.9 AND 2.1 INCHES OVER THE AREA THROUGH THE WEEKEND AND
INTO MONDAY. THEREFORE THE POSSIBILITIES FOR HEAVY RAIN AND
FLOODING INCREASE. A HYDROLOGICAL OUTLOOK HAS BEEN ISSUED WITH
MORE DETAILS. THE GFS CONTINUES TO SHOW THE BEST BANDS OF
PRECIPITATION STRETCHING FROM SOUTH OF PUERTO RICO NORTHEAST
ACROSS THE U.S. VIRGIN ISLANDS AND SOME OF THE HEAVIEST RAINS MAY
FALL THERE AND IN THE CORDILLERA CENTRAL DUE TO OROGRAPHIC ACTION.

MOISTURE LEVELS WILL CONTINUE MUCH HIGHER NEXT WEEK THAN THIS
PAST WEEK...BUT THE MIDDLE OF THE WEEK SHOULD NOT BE AS WET AS
THIS WEEKEND.

AVIATION...VFR CONDS EXPECTED FOR MOST OF THE TERMINALS EXCEPT
TJMZ AND TJPS WHERE AFTERNOON CONVECTION MAY PRODUCE BRIEF
MVFR/IFR CONDS THRU 22Z. MOUNTAIN OBSCURATIONS AND MVFR/IFR CONDS
ARE LIKELY ACROSS THE CORDILLERA CENTRAL THROUGH THIS EVENING..
WINDS BELOW 3K FT WILL PREVAIL FROM THE NE AT AROUND 10
KT...VEERING TO THE SE AFTER 28/06Z.

MARINE...A SWELL OF 8 SECONDS PERIOD...UNDETECTED BY THE
MODELS...MOVED INTO THE ATLANTIC WATERS AND THE WATERS NORTH OF
THE FORECAST AREA RAISING SEAS NEARLY 2 FEET...NEVERTHELESS SEAS
WILL NOT EXCEED 5 FEET THIS WEEK OR WEEKEND SINCE WINDS ARE GENTLE
TO MODERATE. SOME GUSTY WINDS MAY BE ENCOUNTERED IN THUNDERSTORMS
OVER THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  90  76  89 /  20  20  20  40
STT  76  86  78  87 /  20  20  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27





000
FXCA62 TJSJ 280300
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1100 PM AST WED MAY 27 2015

.UPDATE...
VARIABLY TO MOSTLY CLOUDY SKIES WERE OBSERVED ACROSS THE ISLANDS
LATE THIS AFTERNOON AND INTO THE EVENING HOURS. SCATTERED SHOWERS
WERE DETECTED WITH THE DOPPLER RADAR ACROSS THE INTERIOR...WESTERN...
SOUTHEASTERN SECTIONS OF THE ISLANDS. THE HEAVIEST SHOWER ACTIVITY
OCCURRED UNTIL AROUND 8:00 PM AST THIS EVENING. SEVERAL URBAN AND
SMALL STREAM FLOOD ADVISORIES WERE ISSUED FOR RAPID RAISES OF
RIVERS AND SMALL STREAM...AS WELL AS FOR URBAN AND MINOR FLOODING
ACROSS THE MUNICIPALITIES OF ADJUNTAS...PENUELAS...YAUCO...GUAYANILLA
AND UTUADO. WINDS WERE MAINLY FROM THE EAST NORTHEAST AT AROUND 10-15
MPH WITH HIGHER GUSTS AROUND THE SHOWER AND THUNDERSTORM ACTIVITY.

A SIMILAR PATTERN IS EXPECTED ON THURSDAY...WITH MORNING SHOWERS
ACROSS THE U.S. VIRGIN ISLANDS AND THE EASTERN PORTIONS OF PUERTO
RICO FOLLOWED BY AFTERNOON CONVECTION...WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE INTERIOR...WEST AND NORTHWESTERN
SECTIONS OF PUERTO RICO.

MODEL GUIDANCE STILL SUGGESTING THE ARRIVAL OF AN INDUCED TROUGH
ASSOCIATED WITH AN UPPER LOW...NORTHEAST OF PUERTO RICO...BY
FRIDAY. THEREFORE...SHOWER AND TSTORM ACTIVITY IS STILL LIKELY
OVER THE WEEKEND.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL LOCAL TERMINALS DURG MOST OF
PRD. SCT-BKN CLD LYRS NR FL020...FL050..FL120 DUE TO AFTN CONVECTION
TIL 28/04Z DSPTNG CLD COVER THEREAFTER...ISOLD PASSING SHRA EN ROUTE
BTW ISLANDS AND N OF PR FEW TOPS 140-180.  FM 28/17Z-28/22Z...MVFR
PSBL DUE TO AFTN CONVECTION OVR THE CENTRAL MTN RANGE OF PR AND ALSO
NW PORTIONS OF ISLANDS VCTY TJBQ AND TJMZ. WINDS BELOW 6K FT FM NE
AROUND 10 KT...BCMG FM W AND INCR W/HT ABV..MAX WND 50 KTS BTW FL400-
FL450 DURG PRD.

&&

.MARINE...MARINERS CAN EXPECT TRANQUIL WEATHER CONDITIONS WITH
WINDS UP TO 15 KNOTS AND SEAS OF 5 FEET OR LESS.

&&

.PREV DISCUSSION... /ISSUED 330 PM AST WED MAY 27 2015/

SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE ALONG 60 NORTH EAST OF
FLORIDA WILL MOVE NORTHWARD AND REJOIN THE FLOW. THE SUB TROPICAL
JET WILL PULL NORTH OVER THE AREA THURSDAY NIGHT AND FRIDAY THEN HIGH
PRESSURE WILL BUILD OVER THE EASTERN CARIBBEAN OVER THE WEEKEND.
THIS RIDGE WILL SHIFT SLOWLY TOWARD THE WINDWARD PASSAGE DURING
THE UPCOMING WEEK.

AT MID LEVELS...LOW PRESSURE NORTHEAST OF PUERTO RICO WILL PULL
NORTH AND WEAKEN OVER THE WEEKEND THEN HIGH PRESSURE WILL FILL IN
OVER THE EASTERN CARIBBEAN. VERY DRY MID LEVELS WILL GIVE WAY TO A
LARGE AREA OF MOISTURE ON FRIDAY. THIS MOISTURE WILL WEAKEN ON
TUESDAY BUT WILL NOT GET VERY FAR AWAY.

AT LOWER LEVELS...ALTHOUGH HIGH PRESSURE DOMINATES THE CENTRAL
ATLANTIC...VERY WEAK LOWS AND WEAK GRADIENTS ARE FOUND JUST NORTH
AND NORTHEAST OF THE FORECAST AREA. THESE WILL SHIFT WEST AND
FLOW WILL CONTINUE FROM THE SOUTHEAST. TROUGHINESS TO THE WEST AND
THE SOUTHEAST FLOW WILL CONTINUE THROUGH THE UPCOMING WEEK.

DISCUSSION...SHOWERS FORMED MID MORNING AROUND THE U.S. VIRGIN
ISLANDS AND OVER EASTERN PUERTO RICO...BUT HEAVY SHOWERS ERUPTED
QUICKLY JUST AFTER NOON OVER PUERTO RICO...BEING FUELED BY
INTENSE HEATING UNDER THE PREVIOUS SUNNY SKIES. THESE SHOWERS
CONTINUE TO PRODUCE HEAVY RAIN IN THE CENTRAL PORTION OF THE
ISLAND.

THE GFS CONTINUES TO SHOW RELATIVELY DRY AIR OVER THE AREA UNTIL
FRIDAY MORNING THEN MOISTURE INCREASES SHARPLY. ALTHOUGH THE
MOISTURE COLUMN FORECAST FOR THE WEEKEND IS NOT QUITE AS DEEP AS
WAS PREVIOUSLY FORECAST EARLIER THIS WEEK...VALUES STILL HOLD
BETWEEN 1.9 AND 2.1 INCHES OVER THE AREA THROUGH THE WEEKEND AND
INTO MONDAY. THEREFORE THE POSSIBILITIES FOR HEAVY RAIN AND
FLOODING INCREASE. A HYDROLOGICAL OUTLOOK HAS BEEN ISSUED WITH
MORE DETAILS. THE GFS CONTINUES TO SHOW THE BEST BANDS OF
PRECIPITATION STRETCHING FROM SOUTH OF PUERTO RICO NORTHEAST
ACROSS THE U.S. VIRGIN ISLANDS AND SOME OF THE HEAVIEST RAINS MAY
FALL THERE AND IN THE CORDILLERA CENTRAL DUE TO OROGRAPHIC ACTION.

MOISTURE LEVELS WILL CONTINUE MUCH HIGHER NEXT WEEK THAN THIS
PAST WEEK...BUT THE MIDDLE OF THE WEEK SHOULD NOT BE AS WET AS
THIS WEEKEND.

AVIATION...VFR CONDS EXPECTED FOR MOST OF THE TERMINALS EXCEPT
TJMZ AND TJPS WHERE AFTERNOON CONVECTION MAY PRODUCE BRIEF
MVFR/IFR CONDS THRU 22Z. MOUNTAIN OBSCURATIONS AND MVFR/IFR CONDS
ARE LIKELY ACROSS THE CORDILLERA CENTRAL THROUGH THIS EVENING..
WINDS BELOW 3K FT WILL PREVAIL FROM THE NE AT AROUND 10
KT...VEERING TO THE SE AFTER 28/06Z.

MARINE...A SWELL OF 8 SECONDS PERIOD...UNDETECTED BY THE
MODELS...MOVED INTO THE ATLANTIC WATERS AND THE WATERS NORTH OF
THE FORECAST AREA RAISING SEAS NEARLY 2 FEET...NEVERTHELESS SEAS
WILL NOT EXCEED 5 FEET THIS WEEK OR WEEKEND SINCE WINDS ARE GENTLE
TO MODERATE. SOME GUSTY WINDS MAY BE ENCOUNTERED IN THUNDERSTORMS
OVER THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  90  76  89 /  20  20  20  40
STT  76  86  78  87 /  20  20  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27




000
FXCA62 TJSJ 271930
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
330 PM AST WED MAY 27 2015

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE ALONG 60 NORTH EAST OF
FLORIDA WILL MOVE NORTHWARD AND REJOIN THE FLOW. THE SUB TROPICAL
JET WILL PULL NORTH OVER THE AREA THURSDAY NIGHT AND FRIDAY THEN HIGH
PRESSURE WILL BUILD OVER THE EASTERN CARIBBEAN OVER THE WEEKEND.
THIS RIDGE WILL SHIFT SLOWLY TOWARD THE WINDWARD PASSAGE DURING
THE UPCOMING WEEK.

AT MID LEVELS...LOW PRESSURE NORTHEAST OF PUERTO RICO WILL PULL
NORTH AND WEAKEN OVER THE WEEKEND THEN HIGH PRESSURE WILL FILL IN
OVER THE EASTERN CARIBBEAN. VERY DRY MID LEVELS WILL GIVE WAY TO A
LARGE AREA OF MOISTURE ON FRIDAY. THIS MOISTURE WILL WEAKEN ON
TUESDAY BUT WILL NOT GET VERY FAR AWAY.

AT LOWER LEVELS...ALTHOUGH HIGH PRESSURE DOMINATES THE CENTRAL
ATLANTIC...VERY WEAK LOWS AND WEAK GRADIENTS ARE FOUND JUST NORTH
AND NORTHEAST OF THE FORECAST AREA. THESE WILL SHIFT WEST AND
FLOW WILL CONTINUE FROM THE SOUTHEAST. TROUGHINESS TO THE WEST AND
THE SOUTHEAST FLOW WILL CONTINUE THROUGH THE UPCOMING WEEK.

&&

.DISCUSSION...SHOWERS FORMED MID MORNING AROUND THE U.S. VIRGIN
ISLANDS AND OVER EASTERN PUERTO RICO...BUT HEAVY SHOWERS ERUPTED
QUICKLY JUST AFTER NOON OVER PUERTO RICO...BEING FUELED BY
INTENSE HEATING UNDER THE PREVIOUS SUNNY SKIES. THESE SHOWERS
CONTINUE TO PRODUCE HEAVY RAIN IN THE CENTRAL PORTION OF THE
ISLAND.

THE GFS CONTINUES TO SHOW RELATIVELY DRY AIR OVER THE AREA UNTIL
FRIDAY MORNING THEN MOISTURE INCREASES SHARPLY. ALTHOUGH THE
MOISTURE COLUMN FORECAST FOR THE WEEKEND IS NOT QUITE AS DEEP AS
WAS PREVIOUSLY FORECAST EARLIER THIS WEEK...VALUES STILL HOLD
BETWEEN 1.9 AND 2.1 INCHES OVER THE AREA THROUGH THE WEEKEND AND
INTO MONDAY. THEREFORE THE POSSIBILITIES FOR HEAVY RAIN AND
FLOODING INCREASE. A HYDROLOGICAL OUTLOOK HAS BEEN ISSUED WITH
MORE DETAILS. THE GFS CONTINUES TO SHOW THE BEST BANDS OF
PRECIPITATION STRETCHING FROM SOUTH OF PUERTO RICO NORTHEAST
ACROSS THE U.S. VIRGIN ISLANDS AND SOME OF THE HEAVIEST RAINS MAY
FALL THERE AND IN THE CORDILLERA CENTRAL DUE TO OROGRAPHIC ACTION.

MOISTURE LEVELS WILL CONTINUE MUCH HIGHER NEXT WEEK THAN THIS
PAST WEEK...BUT THE MIDDLE OF THE WEEK SHOULD NOT BE AS WET AS
THIS WEEKEND.

&&

.AVIATION...VFR CONDS EXPECTED FOR MOST OF THE TERMINALS EXCEPT
TJMZ AND TJPS WHERE AFTERNOON CONVECTION MAY PRODUCE BRIEF
MVFR/IFR CONDS THRU 22Z. MOUNTAIN OBSCURATIONS AND MVFR/IFR CONDS
ARE LIKELY ACROSS THE CORDILLERA CENTRAL THROUGH THIS EVENING..
WINDS BELOW 3K FT WILL PREVAIL FROM THE NE AT AROUND 10
KT...VEERING TO THE SE AFTER 28/06Z.

&&

.MARINE...A SWELL OF 8 SECONDS PERIOD...UNDETECTED BY THE
MODELS...MOVED INTO THE ATLANTIC WATERS AND THE WATERS NORTH OF
THE FORECAST AREA RAISING SEAS NEARLY 2 FEET...NEVERTHELESS SEAS
WILL NOT EXCEED 5 FEET THIS WEEK OR WEEKEND SINCE WINDS ARE GENTLE
TO MODERATE. SOME GUSTY WINDS MAY BE ENCOUNTERED IN THUNDERSTORMS
OVER THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  75  90  76  89 /  20  20  20  40
STT  74  85  78  87 /  20  20  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/12





000
FXCA62 TJSJ 271557
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1157 AM AST WED MAY 27 2015

.UPDATE...MOSTLY SUNNY SKIES PREVAILED THIS MORNING AT COASTAL LOCATIONS
WHILE MOUNTAIN AREAS REMAINED VARIABLY CLOUDY. SOME SHOWERS HAVE BEGUN
TO DEVELOP OVER EL YUNQUE AND THE CORDILLERA CENTRAL LATE THIS MORNING.
THE OVERALL MOISTURE AND INSTABILITY WILL INCREASE SOMEWHAT THIS AFTERNOON
AS A WEAK BOUNDARY MOVES OVER PR/USVI. IN ADDITION...STEERING FLOW UP
TO 30K FT IS LESS THAN 5 KNOTS. THEREFORE...EXPECT SHOWERS AND A FEW
THUNDERSTORMS DEVELOPING ACROSS THE INTERIOR...WEST AND SOUTH PORTIONS
OF PR THIS AFTERNOON. THE SLOW MOVEMENT OF THIS SHOWERS AND THUNDERSTORMS
COULD LEAD TO MINOR FLOODING IN LOW LYING AREAS AND URBAN AREAS. NO
CHANGES WERE INTRODUCED TO THE FORECAST PACKAGE THIS MORNING.

&&

.AVIATION...VFR CONDS EXPECTED FOR MOST OF THE TERMINAL EXCEPT
TJMZ AND TJPS WHERE AFTERNOON CONVECTION MAY PRODUCE BRIEF MVFR/IFR
CONDS THRU 22Z. WINDS BLW 3K FT WILL PREVAIL FROM THE NE AT AROUND
10 KT...VEERING TO THE SE AFTER 28/06Z.

&&

.MARINE...SEAS OF 2-4 FT AND WINDS OF 10-15 KT CAN BE EXPECTED
THROUGHT TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 553 AM AST WED MAY 27 2015/

SYNOPSIS...UPPER TROUGH AND ASSOCIATED LOW WILL CONTINUE NORTH
OF LOCAL ISLANDS THROUGH FRIDAY. AN INDUCED SURFACE TROUGH NORTHEAST
OF AREA WILL PROMOTE A MODERATE EAST NORTHEAST TRADE WIND FLOW
THROUGH TODAY SURFACE HIGH PRESSURE OVER THE ATLANTIC WILL PREVAIL
FOR THE NEXT SEVERAL DAYS. TROPICAL MOISTURE IS EXPECTED TO
INCREASE BY THIS WEEKEND.

DISCUSSION...PASSING SHOWERS ONCE AGAIN AFFECTED THE LOCAL WATERS
AS WELL AS THE NORTH AND EASTERN SECTIONS OF PR AND THE USVI. THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS ONCE AGAIN EXPECTED ACROSS
THE INTERIOR...WESTERN INTERIOR...AND SOUTHWESTERN PR...WITH A
SLIGHT CHANCE OF RAIN ELSEWHERE IN PR AND IN THE USVI. THIS IS A
TYPICAL PATTERN FOR THIS TIME OF YEAR AND IT IS ONCE AGAIN
EXPECTED ON THURSDAY. HOWEVER ON FRIDAY...TROPICAL MOISTURE IS
EXPECTED TO START INCREASING QUITE A BIT WITH PRECIPITABLE WATER
VALUES GETTING CLOSE TO 2 INCHES. IN COMBINATION WITH THE UPPER
TROUGH...THE INSTABILITY WILL ALSO INCREASE. THIS MAY LEAD TO
ENHANCED THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA STARTING ON
FRIDAY INTO SATURDAY.

LATEST GUIDANCE SUGGESTS THAT THE INSTABILITY WILL BE BETTER JUST
SOUTH OF THE LOCAL ISLANDS BUT INSTABILITY WILL STILL INCREASE
OVER THE ISLANDS. IN ADDITION...THE OVERALL MOISTURE AND THE
UPPER LEVEL DYNAMICS LOOK FAVORABLE FOR SHOWERS AND THUNDERSTORMS
OVER THE LOCAL ISLANDS. BASED ON THE 27/00Z RUN FROM THE GFS
MODEL...THE UPPER LEVEL DIVERGENCE WILL NOT BE THAT GOOD ON
FRIDAY...IN FACT IT SHOWS CONVERGENCE IN THE UPPER LEVELS ON
FRIDAY. HOWEVER...ON SATURDAY...THE MODEL SHOWS A SHARP INCREASE
UN UPPER LEVEL DIVERGENCE WITH CONVERGENCE AT THE SURFACE. THIS
MEANS THAT ALTHOUGH IT LOOKS RAINY ON FRIDAY WITH THE MOISTURE
ADVECTION AND THETA-E INCREASING...THE DAY WITH THE MOST
THUNDERSTORMS MAY ACTUALLY BE ON SATURDAY. THIS IS NOT TO SAY THAT
THERE WILL BE NO THUNDERSTORMS ON FRIDAY...IT JUST THAT THE LATEST
GUIDANCE SUGGESTS BETTER DYNAMICS ON SATURDAY FOR THUNDERSTORMS
OVER THE LOCAL ISLANDS COMPARED TO FRIDAY. SUNDAY LOOKS LIKE THERE
MAY STILL BE SOME THUNDERSTORM ACTIVITY BUT NOT AS MUCH AS
SATURDAY. STAY TUNED FOR THE LATEST ON THIS.

AVIATION...POSBL MVFR IN ISOLD/SCT SHRA THIS MORNING AND TONITE BUT
MOST TAF SITES WL NOT FALL BLW VFR. SCT TSRA THIS AFT INTERIOR AND
SW PR WI SOME OBSCD MTNS...AGAIN WI POSBL VFR AT TJMZ/TJPS. WIND BLW
FL100 ENE 12 KT EARLY TDY BCMG VRBL 12 KT OR LESS LATE TDY TO THU.

MARINE...SEAS MAINLY IN THE 2-4 FT RANGE TODAY AND LIKELY THROUGH
THE END OF THE WORKWEEK. WINDS WILL BE GENERALLY UP TO 15 KNOTS
THROUGH THE END OF THE WORKWEEK AS WELL. WINDS AND SEAS ARE
EXPECTED TO INCREASE SLIGHTLY DURING THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  76  88  78 /  40  20  20  20
STT  87  77  87  77 /  40  20  20  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/99





000
FXCA62 TJSJ 271557
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1157 AM AST WED MAY 27 2015

.UPDATE...MOSTLY SUNNY SKIES PREVAILED THIS MORNING AT COASTAL LOCATIONS
WHILE MOUNTAIN AREAS REMAINED VARIABLY CLOUDY. SOME SHOWERS HAVE BEGUN
TO DEVELOP OVER EL YUNQUE AND THE CORDILLERA CENTRAL LATE THIS MORNING.
THE OVERALL MOISTURE AND INSTABILITY WILL INCREASE SOMEWHAT THIS AFTERNOON
AS A WEAK BOUNDARY MOVES OVER PR/USVI. IN ADDITION...STEERING FLOW UP
TO 30K FT IS LESS THAN 5 KNOTS. THEREFORE...EXPECT SHOWERS AND A FEW
THUNDERSTORMS DEVELOPING ACROSS THE INTERIOR...WEST AND SOUTH PORTIONS
OF PR THIS AFTERNOON. THE SLOW MOVEMENT OF THIS SHOWERS AND THUNDERSTORMS
COULD LEAD TO MINOR FLOODING IN LOW LYING AREAS AND URBAN AREAS. NO
CHANGES WERE INTRODUCED TO THE FORECAST PACKAGE THIS MORNING.

&&

.AVIATION...VFR CONDS EXPECTED FOR MOST OF THE TERMINAL EXCEPT
TJMZ AND TJPS WHERE AFTERNOON CONVECTION MAY PRODUCE BRIEF MVFR/IFR
CONDS THRU 22Z. WINDS BLW 3K FT WILL PREVAIL FROM THE NE AT AROUND
10 KT...VEERING TO THE SE AFTER 28/06Z.

&&

.MARINE...SEAS OF 2-4 FT AND WINDS OF 10-15 KT CAN BE EXPECTED
THROUGHT TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 553 AM AST WED MAY 27 2015/

SYNOPSIS...UPPER TROUGH AND ASSOCIATED LOW WILL CONTINUE NORTH
OF LOCAL ISLANDS THROUGH FRIDAY. AN INDUCED SURFACE TROUGH NORTHEAST
OF AREA WILL PROMOTE A MODERATE EAST NORTHEAST TRADE WIND FLOW
THROUGH TODAY SURFACE HIGH PRESSURE OVER THE ATLANTIC WILL PREVAIL
FOR THE NEXT SEVERAL DAYS. TROPICAL MOISTURE IS EXPECTED TO
INCREASE BY THIS WEEKEND.

DISCUSSION...PASSING SHOWERS ONCE AGAIN AFFECTED THE LOCAL WATERS
AS WELL AS THE NORTH AND EASTERN SECTIONS OF PR AND THE USVI. THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS ONCE AGAIN EXPECTED ACROSS
THE INTERIOR...WESTERN INTERIOR...AND SOUTHWESTERN PR...WITH A
SLIGHT CHANCE OF RAIN ELSEWHERE IN PR AND IN THE USVI. THIS IS A
TYPICAL PATTERN FOR THIS TIME OF YEAR AND IT IS ONCE AGAIN
EXPECTED ON THURSDAY. HOWEVER ON FRIDAY...TROPICAL MOISTURE IS
EXPECTED TO START INCREASING QUITE A BIT WITH PRECIPITABLE WATER
VALUES GETTING CLOSE TO 2 INCHES. IN COMBINATION WITH THE UPPER
TROUGH...THE INSTABILITY WILL ALSO INCREASE. THIS MAY LEAD TO
ENHANCED THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA STARTING ON
FRIDAY INTO SATURDAY.

LATEST GUIDANCE SUGGESTS THAT THE INSTABILITY WILL BE BETTER JUST
SOUTH OF THE LOCAL ISLANDS BUT INSTABILITY WILL STILL INCREASE
OVER THE ISLANDS. IN ADDITION...THE OVERALL MOISTURE AND THE
UPPER LEVEL DYNAMICS LOOK FAVORABLE FOR SHOWERS AND THUNDERSTORMS
OVER THE LOCAL ISLANDS. BASED ON THE 27/00Z RUN FROM THE GFS
MODEL...THE UPPER LEVEL DIVERGENCE WILL NOT BE THAT GOOD ON
FRIDAY...IN FACT IT SHOWS CONVERGENCE IN THE UPPER LEVELS ON
FRIDAY. HOWEVER...ON SATURDAY...THE MODEL SHOWS A SHARP INCREASE
UN UPPER LEVEL DIVERGENCE WITH CONVERGENCE AT THE SURFACE. THIS
MEANS THAT ALTHOUGH IT LOOKS RAINY ON FRIDAY WITH THE MOISTURE
ADVECTION AND THETA-E INCREASING...THE DAY WITH THE MOST
THUNDERSTORMS MAY ACTUALLY BE ON SATURDAY. THIS IS NOT TO SAY THAT
THERE WILL BE NO THUNDERSTORMS ON FRIDAY...IT JUST THAT THE LATEST
GUIDANCE SUGGESTS BETTER DYNAMICS ON SATURDAY FOR THUNDERSTORMS
OVER THE LOCAL ISLANDS COMPARED TO FRIDAY. SUNDAY LOOKS LIKE THERE
MAY STILL BE SOME THUNDERSTORM ACTIVITY BUT NOT AS MUCH AS
SATURDAY. STAY TUNED FOR THE LATEST ON THIS.

AVIATION...POSBL MVFR IN ISOLD/SCT SHRA THIS MORNING AND TONITE BUT
MOST TAF SITES WL NOT FALL BLW VFR. SCT TSRA THIS AFT INTERIOR AND
SW PR WI SOME OBSCD MTNS...AGAIN WI POSBL VFR AT TJMZ/TJPS. WIND BLW
FL100 ENE 12 KT EARLY TDY BCMG VRBL 12 KT OR LESS LATE TDY TO THU.

MARINE...SEAS MAINLY IN THE 2-4 FT RANGE TODAY AND LIKELY THROUGH
THE END OF THE WORKWEEK. WINDS WILL BE GENERALLY UP TO 15 KNOTS
THROUGH THE END OF THE WORKWEEK AS WELL. WINDS AND SEAS ARE
EXPECTED TO INCREASE SLIGHTLY DURING THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  76  88  78 /  40  20  20  20
STT  87  77  87  77 /  40  20  20  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

11/99




000
FXCA62 TJSJ 270953
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
553 AM AST WED MAY 27 2015

.SYNOPSIS...UPPER TROUGH AND ASSOCIATED LOW WILL CONTINUE NORTH
OF LOCAL ISLANDS THROUGH FRIDAY. AN INDUCED SURFACE TROUGH NORTHEAST
OF AREA WILL PROMOTE A MODERATE EAST NORTHEAST TRADE WIND FLOW
THROUGH TODAY SURFACE HIGH PRESSURE OVER THE ATLANTIC WILL PREVAIL
FOR THE NEXT SEVERAL DAYS. TROPICAL MOISTURE IS EXPECTED TO
INCREASE BY THIS WEEKEND.


&&

.DISCUSSION...PASSING SHOWERS ONCE AGAIN AFFECTED THE LOCAL WATERS
AS WELL AS THE NORTH AND EASTERN SECTIONS OF PR AND THE USVI. THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS ONCE AGAIN EXPECTED ACROSS
THE INTERIOR...WESTERN INTERIOR...AND SOUTHWESTERN PR...WITH A
SLIGHT CHANCE OF RAIN ELSEWHERE IN PR AND IN THE USVI. THIS IS A
TYPICAL PATTERN FOR THIS TIME OF YEAR AND IT IS ONCE AGAIN
EXPECTED ON THURSDAY. HOWEVER ON FRIDAY...TROPICAL MOISTURE IS
EXPECTED TO START INCREASING QUITE A BIT WITH PRECIPITABLE WATER
VALUES GETTING CLOSE TO 2 INCHES. IN COMBINATION WITH THE UPPER
TROUGH...THE INSTABILITY WILL ALSO INCREASE. THIS MAY LEAD TO
ENHANCED THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA STARTING ON
FRIDAY INTO SATURDAY.

LATEST GUIDANCE SUGGESTS THAT THE INSTABILITY WILL BE BETTER JUST
SOUTH OF THE LOCAL ISLANDS BUT INSTABILITY WILL STILL INCREASE
OVER THE ISLANDS. IN ADDITION...THE OVERALL MOISTURE AND THE
UPPER LEVEL DYNAMICS LOOK FAVORABLE FOR SHOWERS AND THUNDERSTORMS
OVER THE LOCAL ISLANDS. BASED ON THE 27/00Z RUN FROM THE GFS
MODEL...THE UPPER LEVEL DIVERGENCE WILL NOT BE THAT GOOD ON
FRIDAY...IN FACT IT SHOWS CONVERGENCE IN THE UPPER LEVELS ON
FRIDAY. HOWEVER...ON SATURDAY...THE MODEL SHOWS A SHARP INCREASE
UN UPPER LEVEL DIVERGENCE WITH CONVERGENCE AT THE SURFACE. THIS
MEANS THAT ALTHOUGH IT LOOKS RAINY ON FRIDAY WITH THE MOISTURE
ADVECTION AND THETA-E INCREASING...THE DAY WITH THE MOST
THUNDERSTORMS MAY ACTUALLY BE ON SATURDAY. THIS IS NOT TO SAY THAT
THERE WILL BE NO THUNDERSTORMS ON FRIDAY...IT JUST THAT THE LATEST
GUIDANCE SUGGESTS BETTER DYNAMICS ON SATURDAY FOR THUNDERSTORMS
OVER THE LOCAL ISLANDS COMPARED TO FRIDAY. SUNDAY LOOKS LIKE THERE
MAY STILL BE SOME THUNDERSTORM ACTIVITY BUT NOT AS MUCH AS
SATURDAY. STAY TUNED FOR THE LATEST ON THIS.

&&

.AVIATION...POSBL MVFR IN ISOLD/SCT SHRA THIS MORNING AND TONITE BUT
MOST TAF SITES WL NOT FALL BLW VFR. SCT TSRA THIS AFT INTERIOR AND
SW PR WI SOME OBSCD MTNS...AGAIN WI POSBL VFR AT TJMZ/TJPS. WIND BLW
FL100 ENE 12 KT EARLY TDY BCMG VRBL 12 KT OR LESS LATE TDY TO THU.

&&

.MARINE...SEAS MAINLY IN THE 2-4 FT RANGE TODAY AND LIKELY THROUGH
THE END OF THE WORKWEEK. WINDS WILL BE GENERALLY UP TO 15 KNOTS
THROUGH THE END OF THE WORKWEEK AS WELL. WINDS AND SEAS ARE
EXPECTED TO INCREASE SLIGHTLY DURING THE WEEKEND.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  76  88  78 /  40  20  20  20
STT  87  77  87  77 /  40  20  20  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

54/25




000
FXCA62 TJSJ 270953
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
553 AM AST WED MAY 27 2015

.SYNOPSIS...UPPER TROUGH AND ASSOCIATED LOW WILL CONTINUE NORTH
OF LOCAL ISLANDS THROUGH FRIDAY. AN INDUCED SURFACE TROUGH NORTHEAST
OF AREA WILL PROMOTE A MODERATE EAST NORTHEAST TRADE WIND FLOW
THROUGH TODAY SURFACE HIGH PRESSURE OVER THE ATLANTIC WILL PREVAIL
FOR THE NEXT SEVERAL DAYS. TROPICAL MOISTURE IS EXPECTED TO
INCREASE BY THIS WEEKEND.


&&

.DISCUSSION...PASSING SHOWERS ONCE AGAIN AFFECTED THE LOCAL WATERS
AS WELL AS THE NORTH AND EASTERN SECTIONS OF PR AND THE USVI. THIS
AFTERNOON...SHOWERS AND THUNDERSTORMS ONCE AGAIN EXPECTED ACROSS
THE INTERIOR...WESTERN INTERIOR...AND SOUTHWESTERN PR...WITH A
SLIGHT CHANCE OF RAIN ELSEWHERE IN PR AND IN THE USVI. THIS IS A
TYPICAL PATTERN FOR THIS TIME OF YEAR AND IT IS ONCE AGAIN
EXPECTED ON THURSDAY. HOWEVER ON FRIDAY...TROPICAL MOISTURE IS
EXPECTED TO START INCREASING QUITE A BIT WITH PRECIPITABLE WATER
VALUES GETTING CLOSE TO 2 INCHES. IN COMBINATION WITH THE UPPER
TROUGH...THE INSTABILITY WILL ALSO INCREASE. THIS MAY LEAD TO
ENHANCED THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA STARTING ON
FRIDAY INTO SATURDAY.

LATEST GUIDANCE SUGGESTS THAT THE INSTABILITY WILL BE BETTER JUST
SOUTH OF THE LOCAL ISLANDS BUT INSTABILITY WILL STILL INCREASE
OVER THE ISLANDS. IN ADDITION...THE OVERALL MOISTURE AND THE
UPPER LEVEL DYNAMICS LOOK FAVORABLE FOR SHOWERS AND THUNDERSTORMS
OVER THE LOCAL ISLANDS. BASED ON THE 27/00Z RUN FROM THE GFS
MODEL...THE UPPER LEVEL DIVERGENCE WILL NOT BE THAT GOOD ON
FRIDAY...IN FACT IT SHOWS CONVERGENCE IN THE UPPER LEVELS ON
FRIDAY. HOWEVER...ON SATURDAY...THE MODEL SHOWS A SHARP INCREASE
UN UPPER LEVEL DIVERGENCE WITH CONVERGENCE AT THE SURFACE. THIS
MEANS THAT ALTHOUGH IT LOOKS RAINY ON FRIDAY WITH THE MOISTURE
ADVECTION AND THETA-E INCREASING...THE DAY WITH THE MOST
THUNDERSTORMS MAY ACTUALLY BE ON SATURDAY. THIS IS NOT TO SAY THAT
THERE WILL BE NO THUNDERSTORMS ON FRIDAY...IT JUST THAT THE LATEST
GUIDANCE SUGGESTS BETTER DYNAMICS ON SATURDAY FOR THUNDERSTORMS
OVER THE LOCAL ISLANDS COMPARED TO FRIDAY. SUNDAY LOOKS LIKE THERE
MAY STILL BE SOME THUNDERSTORM ACTIVITY BUT NOT AS MUCH AS
SATURDAY. STAY TUNED FOR THE LATEST ON THIS.

&&

.AVIATION...POSBL MVFR IN ISOLD/SCT SHRA THIS MORNING AND TONITE BUT
MOST TAF SITES WL NOT FALL BLW VFR. SCT TSRA THIS AFT INTERIOR AND
SW PR WI SOME OBSCD MTNS...AGAIN WI POSBL VFR AT TJMZ/TJPS. WIND BLW
FL100 ENE 12 KT EARLY TDY BCMG VRBL 12 KT OR LESS LATE TDY TO THU.

&&

.MARINE...SEAS MAINLY IN THE 2-4 FT RANGE TODAY AND LIKELY THROUGH
THE END OF THE WORKWEEK. WINDS WILL BE GENERALLY UP TO 15 KNOTS
THROUGH THE END OF THE WORKWEEK AS WELL. WINDS AND SEAS ARE
EXPECTED TO INCREASE SLIGHTLY DURING THE WEEKEND.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  76  88  78 /  40  20  20  20
STT  87  77  87  77 /  40  20  20  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

54/25





000
FXCA62 TJSJ 270252
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1052 PM AST TUE MAY 26 2015

.UPDATE...
SHOWERS DEVELOPED ALONG THE SOUTHERN SLOPES OF THE CORDILLERA
CENTRAL...FROM COAMO TO SAN GERMAN...AND OVER SOME SECTIONS OF
MAYAGUEZ. PERIODS OF MODERATE TO HEAVY RAINFALL WERE DETECTED
OBSERVED UNTIL AROUND SUNSET. ONCE AGAIN...BRIEF SHOWERS ARE
EXPECTED OVERNIGHT AND INTO THE MORNING HOURS ACROSS THE U.S.
VIRGIN ISLANDS AND THE NORTH AND EASTERN SECTIONS OF PUERTO
RICO...AND THE SURROUNDING WATERS. DURING THE AFTERNOON
HOURS...SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE
INTERIOR AND WESTERN SECTIONS OF PR. A SIMILAR WEATHER PATTERN
CAN BE EXPECTED FOR THE NEXT FEW DAYS UNTIL DEEPER TROPICAL MOISTURE
ARRIVES ON FRIDAY...WHEN THE MODEL GUIDANCES CONTINUE TO SUGGEST
PWAT AROUND 2.10 IN...WHICH IS AROUND THE 75TH CLIMATOLOGICAL
PERCENTILE FOR THE MONTH OF MAY. THEREFORE...THE CHANCES OF RAIN
ACROSS MANY AREAS IN PUERTO RICO ARE EXPECTED TO INCREASE THIS
WEEKEND. MINOR CHANGES WERE MADE TO THE FORECAST GRIDS.

&&

.AVIATION...
SCT OCNL BKN CLD LYRS BTW FL020-FL080 ACROSS THE FLYING
AREA. ISOLD -SHRA/SHRA OVR COASTAL WATERS N-S-E OF PR AND EN ROUTE
BTW ADJACENT ISLANDS. BRIEF MVFR PSBL AND MTN TOP OBSCR W/PASSING
LOW CLDS AND SHRA... MAINLY OVR AND VCTY E INTERIOR SECTION OF PR
TIL 27/05Z. ELSEWHERE VFR TO PREVAIL DURG PRD. WINDS BLO FL100 FM NE
10 TO 15 KT BMCG FM N AND INCR W/HT ABV. MAX WINDS OVR TJSJ NEXT 24
HRS NR FL450 FM W BTW 45-55 KT. NO OTHER SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...TRANQUIL MARINE CONDITIONS ARE EXPECTED TO CONTINUE AT
LEAST UNTIL THE END OF THE WORK WEEK...WITH SEAS BELOW 5 FEET AND
EAST TO NORTHEAST WINDS AROUND 10 TO 15 KNOTS. WINDS...AND SEAS
ARE EXPECTED TO INCREASE DURING THE WEEKEND.

&&

.PREV DISCUSSION... /ISSUED 225 PM AST TUE MAY 26 2015/

SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL
CONTINUE NORTH OF LOCAL ISLANDS THROUGH FRIDAY. THE TROUGH ALOFT
WILL INDUCE A SURFACE TROUGH ACROSS THE AREA...PROMOTING A MOIST
SOUTHEASTERLY WIND FLOW BY THE END OF THE WEEK. AS TROUGH ALOFT
WEAKENS NEXT WEEK...RIDGE PATTERN WILL BUILD ACROSS THE EASTERN
CARIBBEAN.

DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING MUCH
OF THE DAY ACROSS ALL LOCAL ISLANDS. HOWEVER BY EARLY IN THE
AFTERNOON...SHOWERS WERE FORMING ALONG THE CORDILLERA CENTRAL AND
SOUTHERN SLOPES OF PUERTO RICO. THIS ACTIVITY WILL CONTINUE AT
LEAST UNTIL SUNSET...WITH POSSIBLE ISOLATED THUNDERSTORMS. FOR
TONIGHT...PASSING SHOWERS EMBEDDED WITH THE NORTHEAST WINDS ARE
EXPECTED ACROSS THE USVI AND THE NORTHEASTERN SECTIONS OF PR.

AT LEAST UNTIL THURSDAY...DIURNAL CONVECTION IS EXPECTED ALONG THE
CORDILLERA CENTRAL AND SOUTHWESTERN PR WITH STREAMERS FORMING OFF
THE ISLANDS AND BRIEF PASSING SHOWERS OVER THE WINDWARD AREAS
DURING THE NIGHTTIME. AS DEEP SOUTHERLY WIND FLOW ESTABLISHES DUE
TO THE UPPER LEVEL LOW AND SURFACE TROUGH...A WETTER PATTERN IS
EXPECTED DURING THE END OF WEEK...WITH MODEL GUIDANCE SUGGESTING
ABOVE THAN NORMAL PWAT VALUES FROM FRIDAY AFTERNOON THRU EARLY
NEXT WEEK AND FAVORABLE UPPER AIR DYNAMICS. THEREFORE...SHOWER
AND THUNDERSTORM COVERAGE WILL INCREASE DURING THE WEEKEND ACROSS
THE FORECAST AREA. URBAN AND SMALL STREAM FLOODING IS LIKELY
DURING THIS PERIOD ACROSS MAINLAND PR.

AVIATION...SHRA DVLPG INTO TSRA TIL 26/21Z OVER AND JUST S OF
CORDILLERA CENTRAL. AREAS OF MVFR AND MTN OBSCURATIONS...MAINLY TJMZ
TIL 27/03Z. ELSW VFR TO PREVAIL EXC BRIEF MVFR IN SHRA TKPK AND
TNCM. SHRA AND TSRA TO RETURN TO PR SIMILAR PLACES BY 27/16Z. WINDS
BLO FL090 N-NE 10 TO 15 KT BMCG AFT 27/12Z BLO FL050 E UP TO 12 KT.
MAX WINDS OVR TJSJ NEXT 24 HRS AT FL460 W 45-55 KT.

MARINE...SEAS BELOW 5 FEET AND EAST TO NORTHEAST WINDS AROUND 10
TO 15 KNOTS ARE EXPECTED DURING THE NEXT FEW DAYS. WINDS WILL
INCREASE DURING THE WEEKEND AND SEAS UP TO 6 FEET ARE EXPECTED ON
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  76  88 /  20  20  30  30
STT  76  87  77  87 /  20  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27




000
FXCA62 TJSJ 270252
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1052 PM AST TUE MAY 26 2015

.UPDATE...
SHOWERS DEVELOPED ALONG THE SOUTHERN SLOPES OF THE CORDILLERA
CENTRAL...FROM COAMO TO SAN GERMAN...AND OVER SOME SECTIONS OF
MAYAGUEZ. PERIODS OF MODERATE TO HEAVY RAINFALL WERE DETECTED
OBSERVED UNTIL AROUND SUNSET. ONCE AGAIN...BRIEF SHOWERS ARE
EXPECTED OVERNIGHT AND INTO THE MORNING HOURS ACROSS THE U.S.
VIRGIN ISLANDS AND THE NORTH AND EASTERN SECTIONS OF PUERTO
RICO...AND THE SURROUNDING WATERS. DURING THE AFTERNOON
HOURS...SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE
INTERIOR AND WESTERN SECTIONS OF PR. A SIMILAR WEATHER PATTERN
CAN BE EXPECTED FOR THE NEXT FEW DAYS UNTIL DEEPER TROPICAL MOISTURE
ARRIVES ON FRIDAY...WHEN THE MODEL GUIDANCES CONTINUE TO SUGGEST
PWAT AROUND 2.10 IN...WHICH IS AROUND THE 75TH CLIMATOLOGICAL
PERCENTILE FOR THE MONTH OF MAY. THEREFORE...THE CHANCES OF RAIN
ACROSS MANY AREAS IN PUERTO RICO ARE EXPECTED TO INCREASE THIS
WEEKEND. MINOR CHANGES WERE MADE TO THE FORECAST GRIDS.

&&

.AVIATION...
SCT OCNL BKN CLD LYRS BTW FL020-FL080 ACROSS THE FLYING
AREA. ISOLD -SHRA/SHRA OVR COASTAL WATERS N-S-E OF PR AND EN ROUTE
BTW ADJACENT ISLANDS. BRIEF MVFR PSBL AND MTN TOP OBSCR W/PASSING
LOW CLDS AND SHRA... MAINLY OVR AND VCTY E INTERIOR SECTION OF PR
TIL 27/05Z. ELSEWHERE VFR TO PREVAIL DURG PRD. WINDS BLO FL100 FM NE
10 TO 15 KT BMCG FM N AND INCR W/HT ABV. MAX WINDS OVR TJSJ NEXT 24
HRS NR FL450 FM W BTW 45-55 KT. NO OTHER SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...TRANQUIL MARINE CONDITIONS ARE EXPECTED TO CONTINUE AT
LEAST UNTIL THE END OF THE WORK WEEK...WITH SEAS BELOW 5 FEET AND
EAST TO NORTHEAST WINDS AROUND 10 TO 15 KNOTS. WINDS...AND SEAS
ARE EXPECTED TO INCREASE DURING THE WEEKEND.

&&

.PREV DISCUSSION... /ISSUED 225 PM AST TUE MAY 26 2015/

SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL
CONTINUE NORTH OF LOCAL ISLANDS THROUGH FRIDAY. THE TROUGH ALOFT
WILL INDUCE A SURFACE TROUGH ACROSS THE AREA...PROMOTING A MOIST
SOUTHEASTERLY WIND FLOW BY THE END OF THE WEEK. AS TROUGH ALOFT
WEAKENS NEXT WEEK...RIDGE PATTERN WILL BUILD ACROSS THE EASTERN
CARIBBEAN.

DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING MUCH
OF THE DAY ACROSS ALL LOCAL ISLANDS. HOWEVER BY EARLY IN THE
AFTERNOON...SHOWERS WERE FORMING ALONG THE CORDILLERA CENTRAL AND
SOUTHERN SLOPES OF PUERTO RICO. THIS ACTIVITY WILL CONTINUE AT
LEAST UNTIL SUNSET...WITH POSSIBLE ISOLATED THUNDERSTORMS. FOR
TONIGHT...PASSING SHOWERS EMBEDDED WITH THE NORTHEAST WINDS ARE
EXPECTED ACROSS THE USVI AND THE NORTHEASTERN SECTIONS OF PR.

AT LEAST UNTIL THURSDAY...DIURNAL CONVECTION IS EXPECTED ALONG THE
CORDILLERA CENTRAL AND SOUTHWESTERN PR WITH STREAMERS FORMING OFF
THE ISLANDS AND BRIEF PASSING SHOWERS OVER THE WINDWARD AREAS
DURING THE NIGHTTIME. AS DEEP SOUTHERLY WIND FLOW ESTABLISHES DUE
TO THE UPPER LEVEL LOW AND SURFACE TROUGH...A WETTER PATTERN IS
EXPECTED DURING THE END OF WEEK...WITH MODEL GUIDANCE SUGGESTING
ABOVE THAN NORMAL PWAT VALUES FROM FRIDAY AFTERNOON THRU EARLY
NEXT WEEK AND FAVORABLE UPPER AIR DYNAMICS. THEREFORE...SHOWER
AND THUNDERSTORM COVERAGE WILL INCREASE DURING THE WEEKEND ACROSS
THE FORECAST AREA. URBAN AND SMALL STREAM FLOODING IS LIKELY
DURING THIS PERIOD ACROSS MAINLAND PR.

AVIATION...SHRA DVLPG INTO TSRA TIL 26/21Z OVER AND JUST S OF
CORDILLERA CENTRAL. AREAS OF MVFR AND MTN OBSCURATIONS...MAINLY TJMZ
TIL 27/03Z. ELSW VFR TO PREVAIL EXC BRIEF MVFR IN SHRA TKPK AND
TNCM. SHRA AND TSRA TO RETURN TO PR SIMILAR PLACES BY 27/16Z. WINDS
BLO FL090 N-NE 10 TO 15 KT BMCG AFT 27/12Z BLO FL050 E UP TO 12 KT.
MAX WINDS OVR TJSJ NEXT 24 HRS AT FL460 W 45-55 KT.

MARINE...SEAS BELOW 5 FEET AND EAST TO NORTHEAST WINDS AROUND 10
TO 15 KNOTS ARE EXPECTED DURING THE NEXT FEW DAYS. WINDS WILL
INCREASE DURING THE WEEKEND AND SEAS UP TO 6 FEET ARE EXPECTED ON
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  76  88 /  20  20  30  30
STT  76  87  77  87 /  20  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27





000
FXCA62 TJSJ 270252
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1052 PM AST TUE MAY 26 2015

.UPDATE...
SHOWERS DEVELOPED ALONG THE SOUTHERN SLOPES OF THE CORDILLERA
CENTRAL...FROM COAMO TO SAN GERMAN...AND OVER SOME SECTIONS OF
MAYAGUEZ. PERIODS OF MODERATE TO HEAVY RAINFALL WERE DETECTED
OBSERVED UNTIL AROUND SUNSET. ONCE AGAIN...BRIEF SHOWERS ARE
EXPECTED OVERNIGHT AND INTO THE MORNING HOURS ACROSS THE U.S.
VIRGIN ISLANDS AND THE NORTH AND EASTERN SECTIONS OF PUERTO
RICO...AND THE SURROUNDING WATERS. DURING THE AFTERNOON
HOURS...SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE
INTERIOR AND WESTERN SECTIONS OF PR. A SIMILAR WEATHER PATTERN
CAN BE EXPECTED FOR THE NEXT FEW DAYS UNTIL DEEPER TROPICAL MOISTURE
ARRIVES ON FRIDAY...WHEN THE MODEL GUIDANCES CONTINUE TO SUGGEST
PWAT AROUND 2.10 IN...WHICH IS AROUND THE 75TH CLIMATOLOGICAL
PERCENTILE FOR THE MONTH OF MAY. THEREFORE...THE CHANCES OF RAIN
ACROSS MANY AREAS IN PUERTO RICO ARE EXPECTED TO INCREASE THIS
WEEKEND. MINOR CHANGES WERE MADE TO THE FORECAST GRIDS.

&&

.AVIATION...
SCT OCNL BKN CLD LYRS BTW FL020-FL080 ACROSS THE FLYING
AREA. ISOLD -SHRA/SHRA OVR COASTAL WATERS N-S-E OF PR AND EN ROUTE
BTW ADJACENT ISLANDS. BRIEF MVFR PSBL AND MTN TOP OBSCR W/PASSING
LOW CLDS AND SHRA... MAINLY OVR AND VCTY E INTERIOR SECTION OF PR
TIL 27/05Z. ELSEWHERE VFR TO PREVAIL DURG PRD. WINDS BLO FL100 FM NE
10 TO 15 KT BMCG FM N AND INCR W/HT ABV. MAX WINDS OVR TJSJ NEXT 24
HRS NR FL450 FM W BTW 45-55 KT. NO OTHER SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...TRANQUIL MARINE CONDITIONS ARE EXPECTED TO CONTINUE AT
LEAST UNTIL THE END OF THE WORK WEEK...WITH SEAS BELOW 5 FEET AND
EAST TO NORTHEAST WINDS AROUND 10 TO 15 KNOTS. WINDS...AND SEAS
ARE EXPECTED TO INCREASE DURING THE WEEKEND.

&&

.PREV DISCUSSION... /ISSUED 225 PM AST TUE MAY 26 2015/

SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL
CONTINUE NORTH OF LOCAL ISLANDS THROUGH FRIDAY. THE TROUGH ALOFT
WILL INDUCE A SURFACE TROUGH ACROSS THE AREA...PROMOTING A MOIST
SOUTHEASTERLY WIND FLOW BY THE END OF THE WEEK. AS TROUGH ALOFT
WEAKENS NEXT WEEK...RIDGE PATTERN WILL BUILD ACROSS THE EASTERN
CARIBBEAN.

DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING MUCH
OF THE DAY ACROSS ALL LOCAL ISLANDS. HOWEVER BY EARLY IN THE
AFTERNOON...SHOWERS WERE FORMING ALONG THE CORDILLERA CENTRAL AND
SOUTHERN SLOPES OF PUERTO RICO. THIS ACTIVITY WILL CONTINUE AT
LEAST UNTIL SUNSET...WITH POSSIBLE ISOLATED THUNDERSTORMS. FOR
TONIGHT...PASSING SHOWERS EMBEDDED WITH THE NORTHEAST WINDS ARE
EXPECTED ACROSS THE USVI AND THE NORTHEASTERN SECTIONS OF PR.

AT LEAST UNTIL THURSDAY...DIURNAL CONVECTION IS EXPECTED ALONG THE
CORDILLERA CENTRAL AND SOUTHWESTERN PR WITH STREAMERS FORMING OFF
THE ISLANDS AND BRIEF PASSING SHOWERS OVER THE WINDWARD AREAS
DURING THE NIGHTTIME. AS DEEP SOUTHERLY WIND FLOW ESTABLISHES DUE
TO THE UPPER LEVEL LOW AND SURFACE TROUGH...A WETTER PATTERN IS
EXPECTED DURING THE END OF WEEK...WITH MODEL GUIDANCE SUGGESTING
ABOVE THAN NORMAL PWAT VALUES FROM FRIDAY AFTERNOON THRU EARLY
NEXT WEEK AND FAVORABLE UPPER AIR DYNAMICS. THEREFORE...SHOWER
AND THUNDERSTORM COVERAGE WILL INCREASE DURING THE WEEKEND ACROSS
THE FORECAST AREA. URBAN AND SMALL STREAM FLOODING IS LIKELY
DURING THIS PERIOD ACROSS MAINLAND PR.

AVIATION...SHRA DVLPG INTO TSRA TIL 26/21Z OVER AND JUST S OF
CORDILLERA CENTRAL. AREAS OF MVFR AND MTN OBSCURATIONS...MAINLY TJMZ
TIL 27/03Z. ELSW VFR TO PREVAIL EXC BRIEF MVFR IN SHRA TKPK AND
TNCM. SHRA AND TSRA TO RETURN TO PR SIMILAR PLACES BY 27/16Z. WINDS
BLO FL090 N-NE 10 TO 15 KT BMCG AFT 27/12Z BLO FL050 E UP TO 12 KT.
MAX WINDS OVR TJSJ NEXT 24 HRS AT FL460 W 45-55 KT.

MARINE...SEAS BELOW 5 FEET AND EAST TO NORTHEAST WINDS AROUND 10
TO 15 KNOTS ARE EXPECTED DURING THE NEXT FEW DAYS. WINDS WILL
INCREASE DURING THE WEEKEND AND SEAS UP TO 6 FEET ARE EXPECTED ON
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  76  88 /  20  20  30  30
STT  76  87  77  87 /  20  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27




000
FXCA62 TJSJ 270252 CCA
AFDSJU

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
1052 PM AST TUE MAY 26 2015

.UPDATE...
SHOWERS DEVELOPED ALONG THE SOUTHERN SLOPES OF THE CORDILLERA
CENTRAL...FROM COAMO TO SAN GERMAN...AND OVER SOME SECTIONS OF
MAYAGUEZ. PERIODS OF MODERATE TO HEAVY RAINFALL WERE OBSERVED
UNTIL AROUND SUNSET. ONCE AGAIN...BRIEF SHOWERS ARE EXPECTED
OVERNIGHT AND INTO THE MORNING HOURS ACROSS THE U.S. VIRGIN
ISLANDS AND THE NORTH AND EASTERN SECTIONS OF PUERTO RICO...AND
THE SURROUNDING WATERS. DURING THE AFTERNOON HOURS...SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE INTERIOR AND
WESTERN SECTIONS OF PR. A SIMILAR WEATHER PATTERN CAN BE EXPECTED
FOR THE NEXT FEW DAYS UNTIL DEEPER TROPICAL MOISTURE ARRIVES ON
FRIDAY...WHEN THE MODEL GUIDANCES CONTINUE TO SUGGEST PWAT AROUND
2.10 IN...WHICH IS AROUND THE 75TH CLIMATOLOGICAL PERCENTILE FOR
THE MONTH OF MAY. THEREFORE...THE CHANCES OF RAIN ACROSS MANY
AREAS IN PUERTO RICO ARE EXPECTED TO INCREASE THIS WEEKEND. MINOR
CHANGES WERE MADE TO THE FORECAST GRIDS.

&&

.AVIATION...
SCT OCNL BKN CLD LYRS BTW FL020-FL080 ACROSS THE FLYING
AREA. ISOLD -SHRA/SHRA OVR COASTAL WATERS N-S-E OF PR AND EN ROUTE
BTW ADJACENT ISLANDS. BRIEF MVFR PSBL AND MTN TOP OBSCR W/PASSING
LOW CLDS AND SHRA... MAINLY OVR AND VCTY E INTERIOR SECTION OF PR
TIL 27/05Z. ELSEWHERE VFR TO PREVAIL DURG PRD. WINDS BLO FL100 FM NE
10 TO 15 KT BMCG FM N AND INCR W/HT ABV. MAX WINDS OVR TJSJ NEXT 24
HRS NR FL450 FM W BTW 45-55 KT. NO OTHER SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...TRANQUIL MARINE CONDITIONS ARE EXPECTED TO CONTINUE AT
LEAST UNTIL THE END OF THE WORK WEEK...WITH SEAS BELOW 5 FEET AND
EAST TO NORTHEAST WINDS AROUND 10 TO 15 KNOTS. WINDS...AND SEAS
ARE EXPECTED TO INCREASE DURING THE WEEKEND.

&&

.PREV DISCUSSION... /ISSUED 225 PM AST TUE MAY 26 2015/

SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL
CONTINUE NORTH OF LOCAL ISLANDS THROUGH FRIDAY. THE TROUGH ALOFT
WILL INDUCE A SURFACE TROUGH ACROSS THE AREA...PROMOTING A MOIST
SOUTHEASTERLY WIND FLOW BY THE END OF THE WEEK. AS TROUGH ALOFT
WEAKENS NEXT WEEK...RIDGE PATTERN WILL BUILD ACROSS THE EASTERN
CARIBBEAN.

DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING MUCH
OF THE DAY ACROSS ALL LOCAL ISLANDS. HOWEVER BY EARLY IN THE
AFTERNOON...SHOWERS WERE FORMING ALONG THE CORDILLERA CENTRAL AND
SOUTHERN SLOPES OF PUERTO RICO. THIS ACTIVITY WILL CONTINUE AT
LEAST UNTIL SUNSET...WITH POSSIBLE ISOLATED THUNDERSTORMS. FOR
TONIGHT...PASSING SHOWERS EMBEDDED WITH THE NORTHEAST WINDS ARE
EXPECTED ACROSS THE USVI AND THE NORTHEASTERN SECTIONS OF PR.

AT LEAST UNTIL THURSDAY...DIURNAL CONVECTION IS EXPECTED ALONG THE
CORDILLERA CENTRAL AND SOUTHWESTERN PR WITH STREAMERS FORMING OFF
THE ISLANDS AND BRIEF PASSING SHOWERS OVER THE WINDWARD AREAS
DURING THE NIGHTTIME. AS DEEP SOUTHERLY WIND FLOW ESTABLISHES DUE
TO THE UPPER LEVEL LOW AND SURFACE TROUGH...A WETTER PATTERN IS
EXPECTED DURING THE END OF WEEK...WITH MODEL GUIDANCE SUGGESTING
ABOVE THAN NORMAL PWAT VALUES FROM FRIDAY AFTERNOON THRU EARLY
NEXT WEEK AND FAVORABLE UPPER AIR DYNAMICS. THEREFORE...SHOWER
AND THUNDERSTORM COVERAGE WILL INCREASE DURING THE WEEKEND ACROSS
THE FORECAST AREA. URBAN AND SMALL STREAM FLOODING IS LIKELY
DURING THIS PERIOD ACROSS MAINLAND PR.

AVIATION...SHRA DVLPG INTO TSRA TIL 26/21Z OVER AND JUST S OF
CORDILLERA CENTRAL. AREAS OF MVFR AND MTN OBSCURATIONS...MAINLY TJMZ
TIL 27/03Z. ELSW VFR TO PREVAIL EXC BRIEF MVFR IN SHRA TKPK AND
TNCM. SHRA AND TSRA TO RETURN TO PR SIMILAR PLACES BY 27/16Z. WINDS
BLO FL090 N-NE 10 TO 15 KT BMCG AFT 27/12Z BLO FL050 E UP TO 12 KT.
MAX WINDS OVR TJSJ NEXT 24 HRS AT FL460 W 45-55 KT.

MARINE...SEAS BELOW 5 FEET AND EAST TO NORTHEAST WINDS AROUND 10
TO 15 KNOTS ARE EXPECTED DURING THE NEXT FEW DAYS. WINDS WILL
INCREASE DURING THE WEEKEND AND SEAS UP TO 6 FEET ARE EXPECTED ON
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  76  88 /  20  20  30  30
STT  76  87  77  87 /  20  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27




000
FXCA62 TJSJ 270252 CCA
AFDSJU

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
1052 PM AST TUE MAY 26 2015

.UPDATE...
SHOWERS DEVELOPED ALONG THE SOUTHERN SLOPES OF THE CORDILLERA
CENTRAL...FROM COAMO TO SAN GERMAN...AND OVER SOME SECTIONS OF
MAYAGUEZ. PERIODS OF MODERATE TO HEAVY RAINFALL WERE OBSERVED
UNTIL AROUND SUNSET. ONCE AGAIN...BRIEF SHOWERS ARE EXPECTED
OVERNIGHT AND INTO THE MORNING HOURS ACROSS THE U.S. VIRGIN
ISLANDS AND THE NORTH AND EASTERN SECTIONS OF PUERTO RICO...AND
THE SURROUNDING WATERS. DURING THE AFTERNOON HOURS...SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE INTERIOR AND
WESTERN SECTIONS OF PR. A SIMILAR WEATHER PATTERN CAN BE EXPECTED
FOR THE NEXT FEW DAYS UNTIL DEEPER TROPICAL MOISTURE ARRIVES ON
FRIDAY...WHEN THE MODEL GUIDANCES CONTINUE TO SUGGEST PWAT AROUND
2.10 IN...WHICH IS AROUND THE 75TH CLIMATOLOGICAL PERCENTILE FOR
THE MONTH OF MAY. THEREFORE...THE CHANCES OF RAIN ACROSS MANY
AREAS IN PUERTO RICO ARE EXPECTED TO INCREASE THIS WEEKEND. MINOR
CHANGES WERE MADE TO THE FORECAST GRIDS.

&&

.AVIATION...
SCT OCNL BKN CLD LYRS BTW FL020-FL080 ACROSS THE FLYING
AREA. ISOLD -SHRA/SHRA OVR COASTAL WATERS N-S-E OF PR AND EN ROUTE
BTW ADJACENT ISLANDS. BRIEF MVFR PSBL AND MTN TOP OBSCR W/PASSING
LOW CLDS AND SHRA... MAINLY OVR AND VCTY E INTERIOR SECTION OF PR
TIL 27/05Z. ELSEWHERE VFR TO PREVAIL DURG PRD. WINDS BLO FL100 FM NE
10 TO 15 KT BMCG FM N AND INCR W/HT ABV. MAX WINDS OVR TJSJ NEXT 24
HRS NR FL450 FM W BTW 45-55 KT. NO OTHER SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...TRANQUIL MARINE CONDITIONS ARE EXPECTED TO CONTINUE AT
LEAST UNTIL THE END OF THE WORK WEEK...WITH SEAS BELOW 5 FEET AND
EAST TO NORTHEAST WINDS AROUND 10 TO 15 KNOTS. WINDS...AND SEAS
ARE EXPECTED TO INCREASE DURING THE WEEKEND.

&&

.PREV DISCUSSION... /ISSUED 225 PM AST TUE MAY 26 2015/

SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED LOW WILL
CONTINUE NORTH OF LOCAL ISLANDS THROUGH FRIDAY. THE TROUGH ALOFT
WILL INDUCE A SURFACE TROUGH ACROSS THE AREA...PROMOTING A MOIST
SOUTHEASTERLY WIND FLOW BY THE END OF THE WEEK. AS TROUGH ALOFT
WEAKENS NEXT WEEK...RIDGE PATTERN WILL BUILD ACROSS THE EASTERN
CARIBBEAN.

DISCUSSION...SUNNY TO PARTLY CLOUDY SKIES PREVAILED DURING MUCH
OF THE DAY ACROSS ALL LOCAL ISLANDS. HOWEVER BY EARLY IN THE
AFTERNOON...SHOWERS WERE FORMING ALONG THE CORDILLERA CENTRAL AND
SOUTHERN SLOPES OF PUERTO RICO. THIS ACTIVITY WILL CONTINUE AT
LEAST UNTIL SUNSET...WITH POSSIBLE ISOLATED THUNDERSTORMS. FOR
TONIGHT...PASSING SHOWERS EMBEDDED WITH THE NORTHEAST WINDS ARE
EXPECTED ACROSS THE USVI AND THE NORTHEASTERN SECTIONS OF PR.

AT LEAST UNTIL THURSDAY...DIURNAL CONVECTION IS EXPECTED ALONG THE
CORDILLERA CENTRAL AND SOUTHWESTERN PR WITH STREAMERS FORMING OFF
THE ISLANDS AND BRIEF PASSING SHOWERS OVER THE WINDWARD AREAS
DURING THE NIGHTTIME. AS DEEP SOUTHERLY WIND FLOW ESTABLISHES DUE
TO THE UPPER LEVEL LOW AND SURFACE TROUGH...A WETTER PATTERN IS
EXPECTED DURING THE END OF WEEK...WITH MODEL GUIDANCE SUGGESTING
ABOVE THAN NORMAL PWAT VALUES FROM FRIDAY AFTERNOON THRU EARLY
NEXT WEEK AND FAVORABLE UPPER AIR DYNAMICS. THEREFORE...SHOWER
AND THUNDERSTORM COVERAGE WILL INCREASE DURING THE WEEKEND ACROSS
THE FORECAST AREA. URBAN AND SMALL STREAM FLOODING IS LIKELY
DURING THIS PERIOD ACROSS MAINLAND PR.

AVIATION...SHRA DVLPG INTO TSRA TIL 26/21Z OVER AND JUST S OF
CORDILLERA CENTRAL. AREAS OF MVFR AND MTN OBSCURATIONS...MAINLY TJMZ
TIL 27/03Z. ELSW VFR TO PREVAIL EXC BRIEF MVFR IN SHRA TKPK AND
TNCM. SHRA AND TSRA TO RETURN TO PR SIMILAR PLACES BY 27/16Z. WINDS
BLO FL090 N-NE 10 TO 15 KT BMCG AFT 27/12Z BLO FL050 E UP TO 12 KT.
MAX WINDS OVR TJSJ NEXT 24 HRS AT FL460 W 45-55 KT.

MARINE...SEAS BELOW 5 FEET AND EAST TO NORTHEAST WINDS AROUND 10
TO 15 KNOTS ARE EXPECTED DURING THE NEXT FEW DAYS. WINDS WILL
INCREASE DURING THE WEEKEND AND SEAS UP TO 6 FEET ARE EXPECTED ON
SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  76  88 /  20  20  30  30
STT  76  87  77  87 /  20  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
AM...NONE.
&&

$$

09/27





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