[top]
000
FXCA62 TJSJ 250100
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
900 PM AST TUE NOV 24 2009
.UPDATE...SHOWER ACTIVITY HAS INCREASED ACROSS THE COASTAL WATERS.
ISOLATED SHOWERS WERE DETECTED BY THE DOPPLER WEATHER RADAR LATE
THIS EVENING. HOWEVER...MOST OF THESE SHOWERS WILL BE MAINLY FAST
MOVING AND NO SIGNIFICANT RAINFALL IS EXPECTED. GFS/NAM/ECMWF
COMPUTER MODELS SHOWS AN INCREASE IN MOISTURE FOR TOMORROW DUE
TO AN AREA OF CLOUDINESS AND SHOWERS LOCATED NORTHEAST OF THE
LOCAL ISLANDS. THIS AREA OF MOISTURE IS EXPECTED TO MOVE ACROSS THE
LOCAL AREA TOMORROW...INCREASING SLIGHTLY THE CHANCES FOR
PRECIPITATION. MINOR CHANGES WERE MADE TO GRIDS TO REFLECT THIS
SCENARIO. REST OF FORECAST PACKAGE UNCHANGED.
&&
.AVIATION...VRF CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES
OVERNIGHT. VCSH ARE POSSIBLE ACROSS TJSJ...TIST...TISX...TNCM...AND
TKPK.
&&
.PREV DISCUSSION... /ISSUED 158 PM AST TUE NOV 24 2009/
SYNOPSIS...UPPER LEVEL RIDGE ACROSS ATLANTIC TO MAINTAIN STABLE
AND SUBSIDENT PATTERN ACROSS THE NORTHEAST CARIBBEAN THROUGH
SATURDAY. AT THE SURFACE...HIGH PRESSURE TO BUILD ACROSS THE WESTERN
ATLANTIC AND CENTRAL ATLANTIC NEXT SEVERAL DAYS. FRONTAL TROUGH TO
APPROACH PUERTO RICO FROM THE NORTHWEST ON SUNDAY.
DISCUSSION..NOT MUCH CHANGE TO THE SHORT OR LONG TERM INHERITED
FORECAST. SATELLITE SHHOWS NARROW BANDS OF TRADE WIND CUMULUS
ALIGNED FROM ENE TO WSW ACROSS THE LEEWARDS AND ANEGADA PASSAGE
WHICH SHOULD ACCOUNT FOR ISOLATED TO WIDELY SCATTERED ACTIVITY AS
IT MOVES THROUGH. HIGH PRESSURE ALOFT AND AT SURFACE TO REMAIN AS
THE DOMINANT FEATURE THROUGH FRIDAY PROVIDING LOCAL AREA WITH
GENERALLY STABLE CONDITIONS. ONLY THE TYPICAL NIGHTIME AND EARLY
MORNING SHOWER ACTIVITY SHOULD BE EXPECTED ALONG EAST AND NORTH
PUERTO RICO AND ACROSS THE VIRGIN ISLANDS. AFTERNOONS SHOULD
CONTINUE TO SEE ISOLATED CONVECTION WHICH SHOULD BE LIMITED TO THE
SOUTHWEST THROUGH WEDNESDAY AND AS THE WIND FLOW BECOMES MORE
EASTERLY ON THURSDAY IT SHOULD DISPLACE TO THE WEST AND WEST
INTERIOR. THE UPPER LEVEL ANTICYCLONIC FLOW SHOULD PERSIST THROUGH
NEXT TUESDAY...AND ONLY ON SUNDAY IT APPEARS FAVORABLE FOR A FEW
MORE SHOWERS DUE TO THE UPPER LEVEL IMPULSE MOVING THROUGH.
AVIATION...ALL AIRPORT SITES WILL EXPERIENCE VFR CONDITIONS FOR
THE NEXT 24 HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 75 84 74 86 / 30 10 10 20
STT 76 86 76 86 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
64/71
000
FXCA62 TJSJ 241758
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
158 PM AST TUE NOV 24 2009
.SYNOPSIS...UPPER LEVEL RIDGE ACROSS ATLANTIC TO MAINTAIN STABLE
AND SUBSIDENT PATTERN ACROSS THE NORTHEAST CARIBBEAN THROUGH
SATURDAY. AT THE SURFACE...HIGH PRESSURE TO BUILD ACROSS THE WESTERN
ATLANTIC AND CENTRAL ATLANTIC NEXT SEVERAL DAYS. FRONTAL TROUGH TO
APPROACH PUERTO RICO FROM THE NORTHWEST ON SUNDAY.
&&
.DISCUSSION..NOT MUCH CHANGE TO THE SHORT OR LONG TERM INHERITED
FORECAST. SATELLITE SHHOWS NARROW BANDS OF TRADE WIND CUMULUS
ALIGNED FROM ENE TO WSW ACROSS THE LEEWARDS AND ANEGADA PASSAGE
WHICH SHOULD ACCOUNT FOR ISOLATED TO WIDELY SCATTERED ACTIVITY AS
IT MOVES THROUGH. HIGH PRESSURE ALOFT AND AT SURFACE TO REMAIN AS
THE DOMINANT FEATURE THROUGH FRIDAY PROVIDING LOCAL AREA WITH
GENERALLY STABLE CONDITIONS. ONLY THE TYPICAL NIGHTIME AND EARLY
MORNING SHOWER ACTIVITY SHOULD BE EXPECTED ALONG EAST AND NORTH
PUERTO RICO AND ACROSS THE VIRGIN ISLANDS. AFTERNOONS SHOULD
CONTINUE TO SEE ISOLATED CONVECTION WHICH SHOULD BE LIMITED TO THE
SOUTHWEST THROUGH WEDNESDAY AND AS THE WIND FLOW BECOMES MORE
EASTERLY ON THURSDAY IT SHOULD DISPLACE TO THE WEST AND WEST
INTERIOR. THE UPPER LEVEL ANTICYCLONIC FLOW SHOULD PERSIST THROUGH
NEXT TUESDAY...AND ONLY ON SUNDAY IT APPEARS FAVORABLE FOR A FEW
MORE SHOWERS DUE TO THE UPPER LEVEL IMPULSE MOVING THROUGH.
&&
.AVIATION...ALL AIRPORT SITES WILL EXPERIENCE VFR CONDITIONS FOR
THE NEXT 24 HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 75 84 74 86 / 10 10 10 20
STT 76 86 76 86 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
02/37
000
FXCA62 TJSJ 241403
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1003 AM AST TUE NOV 24 2009
.UPDATE...NO CHANGES TO THE FORECAST WILL BE MADE FOR THIS UPDATE
CYCLE AS WATER VAPOR IMAGERY SHOWS SUBSIDENT AIR IN THE RIGHT
FRONT QUADRANT OF THE SUBTROPICAL JET OVERTAKING THE AREA. LATEST
TJSJ 24/1200Z SOUNDING INDICATES LOW PRECIPITABLE WATER VALUES AND
DEEP DRY AIR ALOFT. THEREFORE...ONLY SMALL CHANCES OF
ISOLATED...SHALLOW SHOWERS AND THUNDERSTORMS ARE POSSIBLE...FORCED
ONLY BY DIURNAL HEATING...OROGRAPHIC LIFT...AND THE SEA BREEZE.
&&
.AVIATION...ALL AIRPORT SITES WILL EXPERIENCE VFR CONDITIONS FOR
THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 227 AM AST TUE NOV 24 2009/
SYNOPSIS...PLENTY OF SUNSHINE AND MINIMAL CHANCES OF
PRECIPITATION IN STORE FOR THE MAJORITY OF THE AREA NEXT SEVERAL
DAYS AS HIGH PRESSURE DOMINATES LOCAL WEATHER PATTERN.
DISCUSSION...DRIEST CONDITIONS OF THE SEASON ONGOING AS TPW
IMAGERY AND EVENING SOUNDING SHOWS PWATS HAVE PLUMMETED TO LOWER
THAN 1.50 INCHES AND CONTINUE TO DROP. STRONG MID LAYER
RIDGE...ALSO EVIDENT ON SAT IMAGERY AND SOUNDING SHOW VERY DRY AIR
PUSHING LOWER DOWN TO THE 700 MB LAYER AS SUBSIDENT AIR MASS
CONTINUES TO BUILD. NO CHANGE NEXT SEVERAL DAYS...AS GFS AND NAM12
IN SOLID AGREEMENT OVER NEXT FEW DAYS BUILDING DEEP LAYERED HIGH
PRESSURE OVER THE CARIBBEAN AND CTRL ATLC. THIS WILL SERVE TO
BLOCK NEXT FRONTAL SYSTEM LATTER HALF OF THIS WEEK...KEEPING
MOISTURE WELL NORTH OF LOCAL AREA. WITH HIGH PRESSURE OVERHEAD IN
THE MID LEVELS...AND SURFACE HIGH BUILDING OVER CLIMO POSITION IN
CTRL ATLC...CLIMO WIND PATTERN ALREADY BACK IN PLACE. VERY LOW
POPS IN FORECAST NEXT FEW DAYS.
AVIATION...VFR ALL SITES.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 84 74 / 10 10 10 10
STT 88 76 86 76 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
02/37
000
FXCA62 TJSJ 240627
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
227 AM AST TUE NOV 24 2009
.SYNOPSIS...PLENTY OF SUNSHINE AND MINIMAL CHANCES OF
PRECIPITATION IN STORE FOR THE MAJORITY OF THE AREA NEXT SEVERAL
DAYS AS HIGH PRESSURE DOMINATES LOCAL WEATHER PATTERN.
&&
.DISCUSSION...DRIEST CONDITIONS OF THE SEASON ONGOING AS TPW
IMAGERY AND EVENING SOUNDING SHOWS PWATS HAVE PLUMMETED TO LOWER
THAN 1.50 INCHES AND CONTINUE TO DROP. STRONG MID LAYER
RIDGE...ALSO EVIDENT ON SAT IMAGERY AND SOUNDING SHOW VERY DRY AIR
PUSHING LOWER DOWN TO THE 700 MB LAYER AS SUBSIDENT AIR MASS
CONTINUES TO BUILD. NO CHANGE NEXT SEVERAL DAYS...AS GFS AND NAM12
IN SOLID AGREEMENT OVER NEXT FEW DAYS BUILDING DEEP LAYERED HIGH
PRESSURE OVER THE CARIBBEAN AND CTRL ATLC. THIS WILL SERVE TO
BLOCK NEXT FRONTAL SYSTEM LATTER HALF OF THIS WEEK...KEEPING
MOISTURE WELL NORTH OF LOCAL AREA. WITH HIGH PRESSURE OVERHEAD IN
THE MID LEVELS...AND SURFACE HIGH BUILDING OVER CLIMO POSITION IN
CTRL ATLC...CLIMO WIND PATTERN ALREADY BACK IN PLACE. VERY LOW
POPS IN FORECAST NEXT FEW DAYS.
&&
.AVIATION...VFR ALL SITES.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 84 74 / 10 10 10 10
STT 88 76 86 76 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
10/93
000
FXCA62 TJSJ 240202
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1002 PM AST MON NOV 23 2009
.SYNOPSIS...THE COMBINATION OF HIGH PRESSURE ACROSS THE SOUTHWEST
ATLANTIC WITH HIGH PRESSURE ACROSS THE WEST AND SOUTHWEST
ATLANTIC...AND A SURFACE TROUGH ACROSS THE CENTRAL ATLANTIC WILL
MAINTAIN A MODERATE EAST NORTHEAST TRADE WINDS ACROSS THE REGION
THROUGH AT LEAST TUESDAY. STRONG MID TO UPPER LEVEL HIGH PRESSURE
RIDGE WILL REMAIN IN PLACE ACROSS THE REGION THROUGH TUESDAY THEN
WEAKEN ACROSS THE AREA ON WEDNESDAY AS AN UPPER TROUGH ACROSS THE
TROPICAL ATLANTIC BECOMES MORE AMPLIFIED...AND A SUBTROPICAL JET
SEGMENT MOVES ACROSS THE NORTHEAST CARIBBEAN WEDNESDAY THROUGH
THURSDAY. THE PRESENT CONDITIONS WILL THEREFORE MAINTAIN AN OVERALL
SUBSIDENT MID TO UPPER LEVEL PATTERN AND A QUIET WEATHER PATTERN
THE REGION THROUGH TUESDAY.
&&
.DISCUSSION...LATEST RADAR AND SATELLITE OBSERVATIONS THIS
EVENING SHOWED ONLY A FEW ISOLATED SHOWERS ACROSS THE SURROUNDING
COASTAL WATERS THIS EVENING. NO PRECIPITATION WAS DETECTED OVER
LAND AREAS SO FAR THIS EVENING. A RELATIVELY DRIER AIR MASS ACROSS
THE NORTHEASTERN CARIBBEAN AND EXTENDING EASTWARD AND
NORTHEASTWARD ACROSS THE ATLANTIC FOR SEVERAL HUNDRED MILES WILL
MAINTAIN A QUIET AND PLEASANT WEATHER PATTERN ACROSS THE LOCAL
ISLANDS UNTIL AT LEAST WEDNESDAY. A SLIGHT INCREASE IN MOISTURE IS
EXPECTED BY LATE WEDNESDAY AND THURSDAY AS A WEAK LOW LEVEL
CONVERGENCE FORMS NEAR THE LOCAL ISLANDS. IN THE MEANTIME...THE
COMBINATION OF THE LIMITED LOW LEVEL MOISTURE WITH DAYTIME HEATING
AND LOCAL TERRAIN EFFECTS WILL INDUCE THE DEVELOPMENT OF SOME
AFTERNOON SHOWERS AND A FEW SHORT LIVED THUNDERSTORMS ACROSS
SOUTHWESTERN AND WESTERN INTERIOR SECTIONS OF PUERTO RICO.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES
TONIGHT. VA EMISSIONS CONTINUE TO EXTEND FROM SOUFRIERE
HILLS...BUT LOW LEVEL WIND FLOW FROM THE EAST NORTHEAST DURING
THE NEXT 24 HRS SHOULD KEEP ASH EMISSIONS WELL SOUTH OF LOCAL
FLYING AREA.
&&
.PREV DISCUSSION... /ISSUED 244 PM AST MON NOV 23 2009/
SYNOPSIS...
HIGH PRESSURE ACROSS THE WEST AND SOUTHWEST ATLANTIC...AND A SURFACE
TROUGH ACROSS THE CENTRAL ATLANTIC WILL MAINTAIN MODERATE EAST
NORTHEAST TRADE WINDS ACROSS THE REGION THROUGH AT LEAST TUESDAY.
STRONG MID TO UPPER LEVEL HIGH PRESSURE RIDGE WILL REMAIN IN PLACE
ACROSS THE REGION THROUGH TUESDAY THEN WEAKEN ACROSS THE AREA ON
WEDNESDAY AS AN UPPER TROUGH ACROSS THE TROPICAL ATLANTIC BECOMES
MORE AMPLIFIED...AND A SUBTROPICAL JET SEGMENT MOVES ACROSS THE
NORTHEAST CARIBBEAN WEDNESDAY THROUGH THURSDAY. THE PRESENT CONDITIONS
WILL THEREFORE MAINTAIN AN OVERALL SUBSIDENT MID TO UPPER LEVEL PATTERN
ACROSS REGION THROUGH TUESDAY.
DISCUSSION...
MOSTLY DRY AND STABLE CONDITIONS WILL PREVAIL ACROSS THE ISLANDS AND
SURROUNDING WATERS FOR THE NEXT 24-36 HOURS. THE PREVAILING NORTHEAST
WINDS WILL CONTINUE...AND AS A RESULT TRANSPORT BRIEF PERIODS OF
QUICK PASSING CLOUDS AND A FEW SHOWERS ACROSS LOCAL WATERS AND
COASTAL AREAS DURING THE LATE EVENING AND EARLY MORNING HOURS.
BY WEDNESDAY AND INTO THURSDAY...THE SURFACE HIGH PRESSURE ACROSS
THE SOUTHWESTERN ATLANTIC AND AN INDUCED TROUGH JUST NORTHEAST OF
THE LEEWARD ISLANDS WILL HELP CREATE A WEAK LOW LEVEL CONVERGENCE
ZONE ACROSS THE AREA. THIS WILL BRING AN INCREASE IN MOISTURE FROM
ACROSS THE REGIONAL WATERS TO THE ISLANDS ESPECIALLY DURING THE
EARLY MORNING HOURS. LATEST GFS MODEL GUIDANCE WHICH INITIALIZED
FAIRLY WELL TODAY...AND ALSO SUGGESTS A SLIGHT INCREASE IN LOW
LEVEL MOISTURE BY WEDNESDAY AND INTO THURSDAY. IN ADDITION AS
MENTIONED ABOVE...UPPER LEVEL CONDITIONS ARE SO FAR EXPECTED TO
BECOME SLIGHTLY MORE FAVORABLE FOR CONVECTIVE DEVELOPMENT DURING
THAT TIME. THEREFORE...EXPECT BETTER CHANCE FOR SHOWERS AND
POSSIBLY ISOLATED THUNDERSTORMS ACROSS PARTS OF THE ISLANDS DURING
THE MIDDLE OF THE WEEK...WITH RAPIDLY IMPROVING CONDITIONS ON
FRIDAY AND INTO THE WEEKEND.
LONG TERM...A COLD FRONT IS FORECAST TO MOVE ACROSS THE SOUTHWEST
ATLANTIC AND STALL WHILE DISSIPATING JUST NORTHWEST OF THE REGION BY
LATE SATURDAY...WITH ITS FRONTAL REMNANTS EVENTUALLY SINKING
SOUTHWARDS ACROSS THE LOCAL ATLANTIC ON SUNDAY AND INTO MONDAY OF
THE NEXT WEEK. HOWEVER...DO NOT FORESEE A SIGNIFICANT INFLUX OF
MOISTURE ACROSS THE REGION AT THIS TIME BUT WILL CONTINUE TO MONITOR
TO SEE IF HOW IT UNFOLDS.
AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES
TONIGHT. VCSH ARE EXPECTED AT LEAST THROUGH 23/22Z IN TJMZ...AND
TJPS. BRIEF PASSING SHOWERS WILL AFFECT TNCM...TKPK...AND TJSJ
OVERNIGHT THROUGH AT LEAST 24/12Z. VA EMISSIONS CONTINUE TO EXTEND
FROM SOUFRIERE HILLS...BUT LOW LEVEL WIND FLOW FROM THE EAST DURING THE
NEXT 24 HRS SHOULD KEEP ASH EMISSIONS WELL SOUTH OF LOCAL FLYING
AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 74 85 / 30 40 40 40
STT 77 87 76 86 / 30 40 40 40
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
64/72
000
FXCA62 TJSJ 231844
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
244 PM AST MON NOV 23 2009
.SYNOPSIS...
HIGH PRESSURE ACROSS THE WEST AND SOUTHWEST ATLANTIC...AND A SURFACE
TROUGH ACROSS THE CENTRAL ATLANTIC WILL MAINTAIN MODERATE EAST
NORTHEAST TRADE WINDS ACROSS THE REGION THROUGH AT LEAST TUESDAY.
STRONG MID TO UPPER LEVEL HIGH PRESSURE RIDGE WILL REMAIN IN PLACE
ACROSS THE REGION THROUGH TUESDAY THEN WEAKEN ACROSS THE AREA ON
WEDNESDAY AS AN UPPER TROUGH ACROSS THE TROPICAL ATLANTIC BECOMES
MORE AMPLIFIED...AND A SUBTROPICAL JET SEGMENT MOVES ACROSS THE
NORTHEAST CARIBBEAN WEDNESDAY THROUGH THURSDAY. THE PRESENT CONDITIONS
WILL THEREFORE MAINTAIN AN OVERALL SUBSIDENT MID TO UPPER LEVEL PATTERN
ACROSS REGION THROUGH TUESDAY.
&&
.DISCUSSION...
MOSTLY DRY AND STABLE CONDITIONS WILL PREVAIL ACROSS THE ISLANDS AND
SURROUNDING WATERS FOR THE NEXT 24-36 HOURS. THE PREVAILING NORTHEAST
WINDS WILL CONTINUE...AND AS A RESULT TRANSPORT BRIEF PERIODS OF
QUICK PASSING CLOUDS AND A FEW SHOWERS ACROSS LOCAL WATERS AND
COASTAL AREAS DURING THE LATE EVENING AND EARLY MORNING HOURS.
BY WEDNESDAY AND INTO THURSDAY...THE SURFACE HIGH PRESSURE ACROSS
THE SOUTHWESTERN ATLANTIC AND AN INDUCED TROUGH JUST NORTHEAST OF
THE LEEWARD ISLANDS WILL HELP CREATE A WEAK LOW LEVEL CONVERGENCE
ZONE ACROSS THE AREA. THIS WILL BRING AN INCREASE IN MOISTURE FROM
ACROSS THE REGIONAL WATERS TO THE ISLANDS ESPECIALLY DURING THE
EARLY MORNING HOURS. LATEST GFS MODEL GUIDANCE WHICH INITIALIZED
FAIRLY WELL TODAY...AND ALSO SUGGESTS A SLIGHT INCREASE IN LOW
LEVEL MOISTURE BY WEDNESDAY AND INTO THURSDAY. IN ADDITION AS
MENTIONED ABOVE...UPPER LEVEL CONDITIONS ARE SO FAR EXPECTED TO
BECOME SLIGHTLY MORE FAVORABLE FOR CONVECTIVE DEVELOPMENT DURING
THAT TIME. THEREFORE...EXPECT BETTER CHANCE FOR SHOWERS AND
POSSIBLY ISOLATED THUNDERSTORMS ACROSS PARTS OF THE ISLANDS DURING
THE MIDDLE OF THE WEEK...WITH RAPIDLY IMPROVING CONDITIONS ON
FRIDAY AND INTO THE WEEKEND.
LONG TERM...A COLD FRONT IS FORECAST TO MOVE ACROSS THE SOUTHWEST
ATLANTIC AND STALL WHILE DISSIPATING JUST NORTHWEST OF THE REGION BY
LATE SATURDAY...WITH ITS FRONTAL REMNANTS EVENTUALLY SINKING
SOUTHWARDS ACROSS THE LOCAL ATLANTIC ON SUNDAY AND INTO MONDAY OF
THE NEXT WEEK. HOWEVER...DO NOT FORESEE A SIGNIFICANT INFLUX OF
MOISTURE ACROSS THE REGION AT THIS TIME BUT WILL CONTINUE TO MONITOR
TO SEE IF HOW IT UNFOLDS.
&&
.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES
TONIGHT. VCSH ARE EXPECTED AT LEAST THROUGH 23/22Z IN TJMZ...AND
TJPS. BRIEF PASSING SHOWERS WILL AFFECT TNCM...TKPK...AND TJSJ
OVERNIGHT THROUGH AT LEAST 24/12Z. VA EMISSIONS CONTINUE TO EXTEND
FROM SOUFRIERE HILLS...BUT LOW LEVEL WIND FLOW FROM THE EAST DURING THE
NEXT 24 HRS SHOULD KEEP ASH EMISSIONS WELL SOUTH OF LOCAL FLYING
AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 74 85 / 30 40 40 40
STT 77 87 76 86 / 30 40 40 40
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
71/09
000
FXCA62 TJSJ 231327
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
927 AM AST MON NOV 23 2009
.UPDATE...LATEST SATELITE IMAGES AS WELL AS TPW PRODUCT FROM
CIMSS INDICATED AN AREA OF DRIER AIR MOVING ACROSS THE U.S. VIRGIN
ISLANDS LATE THIS MORNING. THIS SLOT OF DRY AIR WILL MOVE WEST
DURING THE REST OF THE AFTERNOON LIMITING THE SHOWER ACTIVITY
ACROSS THE LOCAL AREA. HOWEVER...EXIST THE PROBABILITY OF SOME
SHOWER DEVELOPMENT ACROSS THE WESTERN INTERIOR AND SOUTHWEST SECTIONS OF
PUERTO RICO LATE THIS AFTERNOON. ALSO...SOME PASSING SHOWERS ARE
EXPECTED ACROSS THE EASTERN HALF OF PUERTO RICO THE REST OF THE
MORNING HOURS. NO CHANGES TO SHORT TERM GRIDS NEEDED AT THIS TIME.
&&
.AVIATION...VFR ALL SITES NEXT 24 HOURS EXCEPT TJMZ WHICH COULD
SEE A MVFR CIG 18-22Z IN VCSH.
&&
.PREV DISCUSSION... /ISSUED 253 AM AST MON NOV 23 2009/
SYNOPSIS...MID LEVEL HIGH PRESSURE TO DOMINATE THROUGH THE
FORECAST PERIOD...ONLY ALLOWING FOR ONLY ISOLATED TYPICAL AFTERNOON
SHOWERS AND THUNDERSTORMS OVER WESTERN PUERTO RICO EACH AFTERNOON
AND NOCTURNAL PASSING SHOWERS OVER THE WATERS. THE MAJORITY OF THE
AREA WILL ENJOY PLENTY OF SUN FOR THE NEXT 7 DAYS.
DISCUSSION...QUIET WEEK IN STORE AS MID LEVEL RIDGE KEEPS A CAP
ON ANY LARGER SCALE SYSTEMS TO PENETRATE THE REGION. NO
SIGNIFICANT MOISTURE ADVECTION EXPECTED NEXT 7 DAYS...SO LOOKING
FOR VERY ISOLATED ACTIVITY EACH AFTERNOON...WITH FAVORED LOCATIONS
FOR AFTERNOON CONVECTION TO BE LIMITED OVER WESTERN PUERTO RICO.
THE MAJORITY OF THE ISLANDS WILL EXPERIENCE AMPLE SUNSHINE AND A
RETURN TO CLIMO EASTERLY WINDS 10-15 KT. GFS STEADILY BACKING OFF
OF FRONT SWEEPING INTO REGION BY END OF FORECAST PERIOD...SO KEPT
CLIMO GRIDS IN THE EXTENDED.
AVIATION...VFR ALL SITES NEXT 24 HOURS EXCEPT TJMZ WHICH COULD
SEE A MVFR CIG 18-22Z IN VCSH.
MARINE...WEAK NORTHEASTERLY SWELL ENERGY TO PERSIST THROUGH
THIS AFTERNOON WHEN MUCH LONGER PERIOD ENERGY (12-14 SECONDS)
ARRIVES FROM THE SAME DIRECTION. THIS WILL RESULT IN HIGHER
BREAKERS AND COASTAL RUN UP FOR ABOUT 24 HOURS. ANOTHER SET OF
WEAK NELY SWELLS FOR THURSDAY BEFORE NWLY SWELLS BEHIND MID
LATITUDE SYSTEM ARRIVE EARLY THE FOLLOWING WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 86 74 / 20 20 30 30
STT 87 77 87 76 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
71/09
000
FXCA62 TJSJ 230653
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
253 AM AST MON NOV 23 2009
.SYNOPSIS...MID LEVEL HIGH PRESSURE TO DOMINATE THROUGH THE
FORECAST PERIOD...ONLY ALLOWING FOR ONLY ISOLATED TYPICAL AFTERNOON
SHOWERS AND THUNDERSTORMS OVER WESTERN PUERTO RICO EACH AFTERNOON
AND NOCTURNAL PASSING SHOWERS OVER THE WATERS. THE MAJORITY OF THE
AREA WILL ENJOY PLENTY OF SUN FOR THE NEXT 7 DAYS.
&&
.DISCUSSION...QUIET WEEK IN STORE AS MID LEVEL RIDGE KEEPS A CAP
ON ANY LARGER SCALE SYSTEMS TO PENETRATE THE REGION. NO
SIGNIFICANT MOISTURE ADVECTION EXPECTED NEXT 7 DAYS...SO LOOKING
FOR VERY ISOLATED ACTIVITY EACH AFTERNOON...WITH FAVORED LOCATIONS
FOR AFTERNOON CONVECTION TO BE LIMITED OVER WESTERN PUERTO RICO.
THE MAJORITY OF THE ISLANDS WILL EXPERIENCE AMPLE SUNSHINE AND A
RETURN TO CLIMO EASTERLY WINDS 10-15 KT. GFS STEADILY BACKING OFF
OF FRONT SWEEPING INTO REGION BY END OF FORECAST PERIOD...SO KEPT
CLIMO GRIDS IN THE EXTENDED.
&&
.AVIATION...VFR ALL SITES NEXT 24 HOURS EXCEPT TJMZ WHICH COULD
SEE A MVFR CIG 18-22Z IN VCSH.
&&
.MARINE...WEAK NORTHEASTERLY SWELL ENERGY TO PERSIST THROUGH
THIS AFTERNOON WHEN MUCH LONGER PERIOD ENERGY (12-14 SECONDS)
ARRIVES FROM THE SAME DIRECTION. THIS WILL RESULT IN HIGHER
BREAKERS AND COASTAL RUN UP FOR ABOUT 24 HOURS. ANOTHER SET OF
WEAK NELY SWELLS FOR THURSDAY BEFORE NWLY SWELLS BEHIND MID
LATITUDE SYSTEM ARRIVE EARLY THE FOLLOWING WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 86 74 / 20 20 30 30
STT 87 77 87 76 / 20 20 20 20
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&
$$
10/93
| 
