Puerto Rico Weather

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
609 AM AST TUE MAR 24 2015

.SYNOPSIS...MID TO UPPER RIDGING WILL CONTINUE TO BE THE DOMINANT
WEATHER FEATURE FOR THE REST OF THE WEEK. AT THE SURFACE...HIGH
PRESSURE IN THE NORTH CENTRAL ATLANTIC WILL CONTINUE TO GENERATE A
MODERATE TRADE WIND FLOW THAT STRENGTHENS AS A NEW HIGH PRESSURE
MOVES INTO THE WESTERN ATLANTIC BY MID WEEK.


&&

.DISCUSSION...RIDGE ALOFT WILL REMAIN AS THE MAIN WEATHER FEATURE
FOR THE NEXT SEVERAL DAYS...PROVIDING SUBSIDENCE INVERSION OVER
THE REGION. HOWEVER...EAST TO SOUTHEAST LOW LEVEL WINDS ARE
EXPECTED ONCE AGAIN TODAY RESULTING IN SCATTERED SHOWER ACTIVITY
OVER THE INTERIOR AND NORTHWESTERN SECTIONS OF PUERTO RICO AND
WARM TEMPERATURES. MID LEVEL DRYING IS EXPECTED THRU AT LEAST
SATURDAY. WEAK SFC TROUGH WILL REMAIN WELL NORTH OF THE AREA...ONLY
FRAGMENTED PATCHES OF LOW LEVEL CLOUDINESS AND LIGHT PASSING
SHOWERS EMBEDDED WITH THE TRADE WINDS ARE EXPECTED THRU THE END OF
THE WEEK ACROSS THE FORECAST AREA. AN INCREASE ON MOISTURE ACROSS
THE FORECAST AREA IS EXPECTED LATE SUNDAY/ MONDAY.

.AVIATION...BKN CIGS 030-040 DEVELOPING AT JMZ/JBQ AFTER 18Z WITH
SHRA. ESE SFC WINDS 10-15 KT XCPT FOR A WEST WIND AT JMZ AROUND
10 KT.


&&

.MARINE...SEAS BETWEEN 2 TO 4 FEET ARE EXPECTED FOR THE NEXT FEW
DAYS. EAST TO SOUTHEAST WINDS UP TO 15 KNOTS ARE
EXPECTED TODAY...STRENGTHENING THROUGH FRIDAY UP TO 20 KNOTS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 88 75 / 20 10 10 20
STT 85 75 86 75 / 20 20 20 20

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
524 AM AST THU MAR 26 2015

.SYNOPSIS...
BROAD MID/UPPER LEVEL RIDGE WILL REMAIN THE DOMINANT FEATURE
ACROSS THE NORTHEASTERN CARIBBEAN THROUGH THE UPCOMING WEEKEND.
THIS WILL SUPPORT FAIRLY STRONG SUBSIDENCE CAP INVERSION ACROSS
THE FORECAST AREA. BY LATE SUNDAY AND INTO MONDAY HOWEVER...THE
UPPER RIDGE IS TO SLIGHTLY ERODE IN RESPONSE TO A DEEP/AMPLIFYING
LONG WAVE TROUGH MOVING ACROSS THE WESTERN ATLANTIC. MEANWHILE...
STRONG SURFACE HIGH SURFACE WILL CONTINUE TO SHIFT EASTWARD ACROSS
THE WESTERN AND CENTRAL ATLANTIC DURING THE NEXT FEW DAYS. THIS
WILL RESULT IN A TIGHTENING OF THE LOCAL PRESSURE GRADIENT...
RESULTING IN MODERATE EASTERLY TRADE WINDS THROUGH THE END OF THE
WEEK. WINDS ARE TO BECOME MORE SOUTHEASTERLY OVER THE UPCOMING
WEEKEND AS THE SURFACE HIGH MOVES FURTHER EAST...AND A FRONTAL
BOUNDARY AND ASSOCIATED LOW LEVEL CONVERGENCE ZONE WILL APPROACH
THE REGION FROM THE NORTHWEST.

&&

.DISCUSSION...
MOSTLY FAIR WEATHER SKIES EXPECTED ACROSS MUCH OF THE FORECAST
AREA TODAY UNDER MODERATE EASTERLY TRADE WINDS. OCCASIONAL PATCHES
OF TRADE WIND MOISTURE WILL HOWEVER CONTINUE MOVE ACROSS THE REGION.
THIS WILL BE SUFFICIENT TO COMBINE WITH DAYTIME HEATING AND LOCAL
TERRAIN EFFECTS FOR SOME AFTERNOON SHOWER DEVELOPMENT. AFTERNOON
CONVECTION SHOULD BE FOCUSED PRIMARILY OVER PARTS OF THE WESTERN
INTERIOR SECTIONS OF PUERTO RICO. NO SIGNIFICANT RAINFALL ACCUMULATIONS
ARE EXPECTED AS SHOWER DEVELOPMENT WILL BE SUPPRESSED BY THE FAIRLY
STRONG CAP INVERSION.

SIMILAR CONDITIONS EXPECTED ON FRIDAY EXCEPT FOR THE SLIGHT INCREASE
IN THE EASTERLY TRADE WINDS WHICH WILL SUPPORT MORE STREAMER LIKE
AFTERNOON CONVECTION ACROSS PARTS OF THE ISLANDS.

FOR THE UPCOMING WEEKEND...EXPECT A GENERALLY FAIR AND MAINLY
STABLE WEATHER PATTERN TO PREVAIL...AS THE RIDGE ALOFT SHOULD
HOLD IN PLACE AND LIMIT THE SHOWER DEVELOPMENT. HOWEVER...THE
MODERATE EAST TO SOUTHEAST TRADE WINDS WILL CONTINUE TO BRING
PERIODS OF EARLY MORNING SHOWERS TO SOME OF ISLANDS...FOLLOWED BY
ISOLATED TO SCATTERED AFTERNOON SHOWERS MAINLY ACROSS THE INTERIOR
AND WEST TO NORTHWEST SECTIONS OF PUERTO RICO.

BY LATE SUNDAY AND INTO EARLY PART OF NEXT WEEK THE APPROACH OF A
FRONTAL BOUNDARY AND CONVERGENCE ZONE/SHEAR LINE WILL ALLOW FOR AN
INCREASE IN LOW LEVEL MOISTURE. THIS WILL INCREASE THE CHANCES FOR
MORE SHOWER DEVELOPMENT ACROSS THE COASTAL WATERS AND PARTS OF THE
ISLANDS.

&&

.AVIATION...MOSTLY VFR CONDITIONS EXPECTED THROUGH THE NEXT 24
HOURS. ISOLATED -SHRA EXPECTED ACROSS THE LOCAL FLYING AREA BUT ARE
NOT EXPECTED TO HAVE A SIGNIFICANT IMPACT ON THE LOCAL FLYING AREA.
LIGHT EAST TO EAST NORTHEAST WINDS AT 5-10 KNOTS DURING THE EARLY
MORNING HOURS INCREASING TO AROUND 15 KNOTS AND GUSTY AFTER 26/14Z.
SCATTERED SHRA EXPECTED ACROSS WESTERN PR THIS AFTERNOON...INDUCING
VCSH AT TJMZ...WITH POSSIBLE CIGS AT FL040 AND TEMPO SHRA AT THE
TJMZ TERMINAL AFTER 26/18Z WITH LOCAL MOUNTAIN OBSCURATIONS.

&&

.MARINE....MARINE WILL CONTINUE RELATIVELY TRANQUIL MOST OF TODAY...
BUT THE MODERATE TRADE WINDS WILL AID IN SLIGHTLY INCREASING SEAS
TO NEAR 6 FEET IN EXPOSED WATERS OVERNIGHT THROUGH FRIDAY. FOR NOW
SMALL CRAFT ADVISORIES ARE NOT EXPECTED...BUT SMALL CRAFT OPERATORS
SHOULD EXERCISE CAUTION FROM THEN ON AND INTO THE UPCOMING WEEKEND
MAINLY DUE TO THE MODERATE TO LOCALLY FRESH TRADE WINDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 89 76 / 20 30 30 30
STT 86 75 86 75 / 20 30 30 30

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
453 AM AST SAT MAR 28 2015

.SYNOPSIS...BROAD MID TO UPPER LEVEL RIDGE WILL CONTINUE AS THE MAIN
WEATHER FEATURE ACROSS THE REGION THROUGH SUNDAY. BY SUNDAY NIGHT
AND INTO MONDAY THE MID TO UPPER RIDGE WILL ERODE IN RESPONSE TO A
DEEP/AMPLIFYING LONG WAVE TROUGH MOVING ACROSS THE WESTERN ATLANTIC.

&&

.DISCUSSION...DOPPLER WEATHER RADAR DETECTED ONLY FEW ISOLATED
PASSING SHOWERS OVER THE SURROUNDING WATERS OVERNIGHT AND EARLY THIS
MORNING...BUT NO PRECIPITATION WAS DETECTED OVER LAND AREAS AS THE
NORTHEAST CARIBBEAN REMAINS UNDER THE INFLUENCE OF A MID TO UPPER
LEVEL RIDGE. THIS FEATURE IS EXPECTED TO REMAINS AS THE MAIN WEATHER
FEATURE TODAY AND EARLY SUNDAY...PROVIDING SUBSIDENCE INVERSION OVER
THE REGION. THUS...LIMITED SHOWER ACTIVITY IS EXPECTED FOR THE REST
OF THE WEEKEND WITH ONLY THE TYPICAL TRADE WIND SHOWERS OVER THE
U.S. VIRGIN ISLANDS AND EASTERN PUERTO RICO OVERNIGHT AND EARLY IN
THE MORNINGS WITH SOME CONVECTION ACROSS WESTERN AND INTERIOR
SECTIONS OF PUERTO RICO EACH AFTERNOON. BY LATE SUNDAY INTO THE
EARLY PART OF NEXT WEEK...LATEST GFS MODEL GUIDANCE MODEL CONTINUED
TO SUGGEST THE DISSIPATING FRONTAL BOUNDARY/SHEAR LINE TO STALL JUST
NORTH OF THE REGION. EXPECT SOME LOW LEVEL MOISTURE TRANSPORT AND
CONVERGENCE ACROSS THE FORECAST AREA TO INCREASE THE CHANCES FOR
SHOWER DEVELOPMENT ACROSS THE COASTAL WATERS AND PARTS OF THE
ISLANDS. IN ADDITION...THE EROSION OF THE UPPER LEVEL RIDGE BY LATE
SUNDAY AND MONDAY...WILL ALSO SLIGHTLY INCREASE THE POTENTIAL FOR
ISOLATED THUNDERSTORMS IN RESPONSE TO WEAKENING CAP INVERSION.
SOME DRYING EXPECTED WEDNESDAY NIGHT INTO THURSDAY.

&&

.AVIATION...VFR CONDS EXPECTED AT ALL TAF SITES THRU THE FORECAST
PERIOD. CHC OF BRIEF MVFR CONDS IN CIG/SHRA FROM 28/18Z TO 28/22Z IN
AND AROUND TJBQ/TJMZ. SFC WINDS TIL 28/12Z EAST LESS THAN 10 KTS...
AFT 28/14Z...MAINLY FM E AT 10-15 KT GUSTING TO NEAR 25 KTS WITH
LOCAL SEA BREEZE VARIATIONS. L/LVL WNDS ESE UP TO 25 KNOTS BLO
FL100...BCMG FM N AND DECR W/HT UP TO FL250...THEN FM NW AND INCR
W/H TO MAX WND AROUND 45 KTS NR FL400.NO SIG OPERATIONAL WX IMPACTS
ATTM.

&&

.MARINE...
WINDS UP TO 20 KNOTS AND SEAS UP TO 6 FEET ARE EXPECTED ACROSS
THE REGIONAL WATERS. HOWEVER OCASSIONALLY SEAS WILL REACH UP TO 8
FEET FOR SHORT PERIODS OF TIME. SMALL CRAFT ARE URGED TO EXERCISE
CAUTION ACROSS MOST OF THE LOCAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 74 88 75 / 0 10 10 10
STT 86 75 85 74 / 10 10 10 10

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
522 AM AST MON MAR 30 2015

.SYNOPSIS...AT UPPER LEVELS...ALTHOUGH HIGH PRESSURE WILL REMAIN
OVER MOST OF THE CARIBBEAN...A TROUGH WILL GRADUALLY ERODE
HEIGHTS TODAY THROUGH THURSDAY OVER THE NORTHEAST CARIBBEAN. A
SECOND AND DEEPER TROUGH WILL APPROACH THE LOCAL AREA FRIDAY
THROUGH SUNDAY. THEN HIGH PRESSURE OVER THE WESTERN CARIBBEAN
WILL FLATTEN OUT OVER THE AREA EARLY NEXT WEEK.

AT MID LEVELS...AN APPROACHING LONG WAVE TROUGH OVER THE MID
LATITUDES WILL CAUSE THE HIGH OVER THE CARIBBEAN TO SHIFT INTO THE
TROPICAL ATLANTIC BY MID WEEK. A TROUGH WILL PASS BY NEXT THURSDAY
BUT A CUT-OFF LOW WILL COME VERY CLOSE TO THE AREA FROM THE
NORTHWEST SATURDAY NIGHT.

AT LOWER LEVELS...A FRONTAL BAND WILL MOVE TOWARD THE AREA FROM
THE NORTHWEST TODAY THROUGH THURSDAY. LOCAL DISTURBANCES WILL
BRING MOISTURE TO THE LOCAL AREA IN THIS BAND THURSDAY THROUGH
SATURDAY. HIGH PRESSURE WILL MOVE INTO THE CENTRAL WESTERN
ATLANTIC LATE IN THE WEEK WITH HIGHER PRESSURE NORTH OF THE AREA
THROUGH MID-WEEK NEXT WEEK. SURFACE WINDS WILL INCREASE FRIDAY AND
SATURDAY...BUT WILL NOT BE AS STRONG AS DURING THE PREVIOUS WEEK.

&&

.DISCUSSION...SHOWERS INCREASED OVER THE ATLANTIC AND THE
CARIBBEAN EAST OF SAN JUAN DURING THE EARLY MORNING HOURS...WITH
MOST OF THE SHOWERS WEST AND SOUTHWEST OF SAINT CROIX. CELL
MOVEMENTS HAVE BEEN NE-ENE IN SPITE OF THE MORE EASTERLY SURFACE
FLOW. THE GFS AND THE NAM5 MODELS SHOW THIS AS A NARROW BAND THAT
TRANSVERSES PUERTO RICO DURING THE DAY AND WILL AUGMENT SHOWERS IN
THE WESTERN HALF THIS AFTERNOON. LATER THIS AFTERNOON SHOWERS ARE
EXPECTED TO FAVOR THE NORTHWEST SINCE WINDS AT THE SURFACE BEGIN TO
BECOME MORE SOUTHEASTERLY. A VERY PRONOUNCED DRY SLOT IS DEPICTED
IN THE GFS AND NAM MODELS AND WILL TEND TO CLEAR OUT MOST OF THE
SHOWERS OVERNIGHT. AFTER THIS...MOISTURE AND SHOWERS BUILD EACH DAY
THROUGH THURSDAY AS A WEAK DISTURBANCE FORMS IN CONNECTION WITH
THE PROXIMITY OF THE FRONTAL BAND JUST TO THE NORTHWEST. THIS
MOISTURE SPREADS OVER THE AREA AND WILL BRING BETTER SHOWER
ACTIVITY THURSDAY AND FRIDAY. THEN BEFORE THE MOISTURE CAN
COMPLETELY LEAVE THE AREA AT MID LEVELS...A CUT-OFF LOW APPROACHES
THE AREA FRIDAY AND SATURDAY WITH 500 MB TEMPERATURES DROPPING
FROM MINUS 7.2 DEGREES ON THURSDAY TO AS LOW AS MINUS 10 DEGREES
ON SATURDAY. THE PROXIMITY OF THE LOW...THE DEPTH OF THE MOISTURE
AND THE INCREASING INSTABILITY WILL GREATLY ENHANCE THE
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE AREA BEGINNING
THURSDAY. PRECIPITABLE WATER VALUES WILL PEAK AT AROUND 1.8 INCHES
ON THURSDAY BUT WILL NOT DROP BELOW 1.4 INCHES UNTIL MID-WEEK NEXT
WEEK...WHICH VALUES THEY ARE EXPECTED TO REACH BY WEDNESDAY OF THIS
WEEK. JUST AS MID LEVEL FLOW SHIFTS TO THE NORTHWEST AROUND THE
CUT-OFF LOW TO BRING IN DRIER AIR ON SATURDAY THE LOW MOVES TO THE
EAST AND MOISTURE RETURNS FROM THE NORTHEAST...SUCH THAT SOME
CLOUDS WILL CONTINUE INTO THE BEGINNING OF NEXT WEEK.

THOUGH TOO FAR OUT TO BE DEFINITIVE...CURRENT INDICATIONS ARE THAT
SUNDAY`S SUNRISE WILL BE RELATIVELY DRY ON THE NORTHERN AND
SOUTHERN COASTS OF PUERTO RICO WITH SCATTERED SHOWERS ON THE EAST
COASTS AND IN THE U.S. VIRGIN ISLANDS.

&&

.AVIATION...MAINLY VFR CONDITIONS EXPECTED AT ALL TAF SITES THRU THE
FORECAST PERIOD. SCT/BKN LAYERS AROUND FL060 WILL CLEAR AROUND
30/12Z OVER TIST/TISX. SHRA ARE STILL POSSIBLE IN/AROUND
TIST/TISX/TJSJ/TNCM DURING THE MORNING HOURS...THEN SHRA ARE
LIKELY BETWEEN 30/18-22Z IN AND AROUND TJMZ/TJBQ WITH BRIEF MVFR
CONDITIONS AND MTN OBSCURATIONS. LIGHT AND VARIABLE WINDS...AFT
30/12Z WINDS WILL CONTINUE FROM THE EAST TO SOUTHEAST AT 10-15
KTS...WITH SEA BREEZES.


&&

.MARINE...ALTHOUGH SEAS WILL INCREASE AND SUBSIDE SOMEWHAT TUESDAY
AND FRIDAY...THE HIGHEST SEAS ARE EXPECTED ON SATURDAY IN THE
ATLANTIC. SMALL CRAFT ADVISORIES MAY BE NECESSARY FOR SEAS ON
SATURDAY AND EARLY SUNDAY IN CURRENT PROJECTIONS FOR THE ATLANTIC
OUTER WATERS. WINDS OVER THE LOCAL WATERS WILL LIKELY PEAK FRIDAY
AND THE FOLLOWING WEDNESDAY. SEAS IN THE CARIBBEAN ARE EXPECTED TO
BE LOWER. THEY WILL PEAK WEDNESDAY AND FRIDAY AROUND 5 TO 6 FEET.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 87 75 / 10 10 10 30
STT 84 73 85 74 / 20 10 10 30

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
620 AM AST WED APR 1 2015

.SYNOPSIS...FLAT UPPER LEVEL RIDGE WILL CONTINUE OVER THE REGION
TODAY...COLLAPSING BY THURSDAY...AS AN UPPER LEVEL TROUGH...NOW
OVER THE WESTERN ATLANTIC...AMPLIFIES OVER THE REGION THURSDAY
INTO THE WEEKEND.

AT THE SURFACE LEVEL...A STATIONARY FRONTAL BOUNDARY IS OFF TO THE
NORTH OF THE LOCAL AREA AND WILL CONTINUE DURING THE NEXT FEW
DAYS. A SURFACE HIGH PRESSURES WILL MIGRATE EASTWARD ACROSS THE
WESTERN ATLANTIC AND INTO THE CENTRAL ATLANTIC...TIGHTENING THE
LOCAL PRESSURE GRADIENT THURSDAY THROUGH SUNDAY. LOCAL TRADE WINDS
WILL INCREASE AFTER THURSDAY AND DURING THE UPCOMING WEEKEND.

&&

.DISCUSSION...SATELLITE IMAGES AND MODEL GUIDANCE ARE INDICATING
A HUMID AIR MASS APPROACHING THE ISLANDS. THIS AIR MASS WILL REACH
THE CWA TODAY...TO PRODUCE AN INCREMENT IN SHOWER ACTIVITY. THIS
MORNING... SHOWERS WILL FOCUS ACROSS THE EASTERN HALF OF PUERTO
RICO AND THE US VIRGIN ISLANDS. DURING THE AFTERNOON...THE
COMBINATION OF THE AVAILABLE MOISTURE AND LOCAL EFFECTS WILL
ENHANCE THE FORMATION OF SHOWERS MAINLY ACROSS THE INTERIOR AND
WESTERN PUERTO RICO. ALSO SHOWERS MAY FORM IN THE WAKE OF THE
ISLANDS OF VIEQUES...CULEBRA...ST THOMAS AND ST CROIX.

INCLEMENT WEATHER IS EXPECTED AS THE UPPER LEVEL RIDGE COLLAPSE
AND AN UPPER LEVEL TROUGH BUILDS OVER THE REGION THURSDAY INTO THE
WEEKEND. THEREFORE...POTENTIAL FOR MODERATE TO HEAVY SHOWERS AND
T-STORMS EXIST DURING THIS DAYS UNDER IMPROVING JET DYNAMICS. WX
CONDITIONS BEGIN TO IMPROVE ON SUNDAY.

&&

.AVIATION...MAINLY VFR CONDS NEXT 24 HOURS ACROSS ALL TAF SITES.
BRIEF PASSING VCSH MAY AFFECT TIST/TISX/TNCM/TKPK BFR 01/12Z. THEN
AFT 01/18Z...SHRA WILL DEVELOP IN AND AROUND TJBQ/TJMZ...TO CREATE
AREAS OF MVFR CONDS AND MTN OBSCURATIONS. WINDS BLO FL090 EAST TO
SOUTHEAST WINDS WILL CONTINUE AT 10 TO 15 KT WITH SOME HIGHER GUSTS
...ESPECIALLY IN SEA BREEZE VARIATIONS AFTER 14Z.

&&

.MARINE...ACROSS THE ATLANTIC WATERS CAN EXPECT SEAS BETWEEN 5-6
FT. THEREFORE...SMALL CRAFT OPERATORS SHOULD EXERCISE CAUTION
ACROSS THESE WATERS. ON THE OTHER HAND...ACROSS THE CARIBBEAN
WATERS EXPECTED SEAS BETWEEN 3 AND 5 FEET. WINDS WILL CONTINUE
FROM THE EAST UP TO 15 KT. TRADE WINDS ARE EXPECTED TO INCREASE
AFTER WEDNESDAY AS A HIGH PRESSURE MOVES EASTWARD ACROSS THE
ATLANTIC WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 85 75 / 30 40 40 30
STT 82 75 83 74 / 40 40 40 20

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
553 AM AST FRI APR 3 2015

.SYNOPSIS...SURFACE HIGH PRESSURE NORTH OF THE AREA WILL CONTINUE
TO PRODUCE MODERATE TO FRESH TRADE WINDS ACROSS THE LOCAL REGION
THROUGH THE WEEKEND. THESE WINDS WILL CONTINUE TO TRANSPORT
PATCHES OF LOW LEVEL MOISTURE ACROSS THE REGION FROM TIME TO
TIME. UPPER LEVEL TROUGH WILL PASS THROUGH THE AREA SATURDAY.

&&

.DISCUSSION...SHOWERS WERE SEEN SOUTH OF THE LOCAL ISLANDS...WITH
DRY AIR TO OUR NORTH. VERY LITTLE SHOWER ACTIVITY WAS OBSERVED
OVER LAND AREAS OVERNIGHT. FOR TODAY AND THROUGH THE
WEEKEND...SURFACE HIGH PRESSURE NORTH OF THE AREA WILL CONTINUE TO
DOMINATES THE REGION. THIS HIGH PRESSURE WILL CONTINUE TO PRODUCE
MODERATE TO FRESH TRADE WINDS ACROSS THE REGION THROUGH AT LEAST
SUNDAY. THESE WINDS WILL CONTINUE TO TRANSPORT PATCHES OF LOW
LEVEL MOISTURE ACROSS THE LOCAL AREA.

MAINLY PLEASANT WEATHER CONDITIONS ARE IN STORE FOR PUERTO RICO
AND THE U.S. VIRGIN ISLANDS TODAY AND TONIGHT...WITH SOME SHOWERS
EXPECTED TO DEVELOP OVER THE WESTERN INTERIOR AND SOUTHWEST
SECTIONS OF PUERTO RICO. PASSING SHOWERS WILL BE POSSIBLE OVER THE
U.S. VIRGIN ISLANDS. FOR SATURDAY...AN UPPER LEVEL TROUGH WILL
MOVE ACROSS THE REGION...ENHANCING THE DEVELOPMENT OF SHOWERS
ACROSS THE LOCAL AREA. ALTHOUGH THE TROUGH IS EXPECTED TO BE DEEP
ENOUGH...MOISTURE WILL BE LIMITED AT LOW LEVEL...WITH PRECIPITABLE
WATER VALUES REMAINING NEAR 1.2 INCHES. IN ADDITION...THETA-E
VALUES AT 700 MB ARE EXPECTED TO DROP TO NEAR 315K...WHICH IS
TYPICALLY A LOW VALUE FOR SHOWER AND THUNDERSTORMS FORMATION.
ALTHOUGH ONE OR TWO ISOLATED THUNDERSTORMS COULD DEVELOP BRIEFLY
SATURDAY AFTERNOON...AT THIS TIME...NO SIGNIFICANT COVERAGE OF
ACTIVE WEATHER IS EXPECTED. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THE TROUGH NEXT 24-36 HOURS AND WILL ADJUST FORECAST IF
NECESSARY.

&&

.AVIATION...DRIER AIR IS STARTING TO PENETRATE FROM THE NORTHEAST
REDUCING SHOWER ACTIVITY TO ISOLATED OVER WATERS NE OF TJSJ
INCLUDING TAF SITES TIST...TNCM AND TKPK...OTHERWISE SCT SHRA WILL CONT.
THIS TREND WILL CONT THRU 04/02Z. EXCEPT AFT 03/16Z SHRA WILL DEVELOP
OVR INTERIOR PR TO INCLUDE TJMZ AND DOWNSTREAM FROM TIST AND TISX. WRN
PR SHLD EXPECT AREAS OF MVFR AND MTN OBSCURATIONS TIL AFT 03/23Z.
WINDS ALF ENE 10 TO 20 KT BLO FL100.

&&

.MARINE...WINDS AROUND 20 KTS AND SEAS UP TO 6 FEET ARE EXPECTED
TO PREVAIL ACROSS THE LOCAL COASTAL WATERS TODAY. SMALL CRAFT
SHOULD EXERCISE CAUTION ACROSS MOST COASTAL WATERS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 84 75 / 20 30 30 30
STT 79 76 84 77 / 20 30 30 30

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
546 AM AST SUN APR 5 2015

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC WILL
CONTINUE TO PRODUCE MODERATE TRADE WINDS ACROSS THE LOCAL AREA
NEXT SEVERAL DAYS. THESE WINDS WILL CONTINUE TO TRANSPORT PATCHES
OF LOW LEVEL MOISTURE ACROSS THE REGION. UPPER LEVEL TROUGH WILL
DEVELOP ACROSS THE WESTERN ATLANTIC MID WEEK.

&&

.DISCUSSION...SHOWERS INCREASED OVERNIGHT OVER THE ATLANTIC
COASTAL WATERS IN RESPONSE TO AN UPPER LEVEL TROUGH WHICH WILL
CONTINUE TO MOVE AWAY FROM THE AREA. IN THE MEANTIME...THESE
SHOWERS WILL BE TRANSPORTED BY THE NORTHEAST WIND FLOW WHICH
PREVAILS ACROSS THE REGION. THEREFORE...SOME PASSING SHOWERS ARE
EXPECTED THIS MORNING ALONG THE NORTHER U.S. VIRGIN ISLANDS AND
THE NORTH AND EAST SECTIONS OF PUERTO RICO. FOR THIS
AFTERNOON...ALTHOUGH DRIER AIR IS EXPECTED TO MOVE ACROSS THE
AREA...AVAILABLE MOISTURE WILL COMBINE WITH DAYTIME HEATING AND
OROGRAPHIC EFFECTS TO PRODUCE SOME SHOWERS AND POSSIBLE
THUNDERSTORMS OVER THE WESTERN INTERIOR AND SOUTHWEST SECTIONS OF
PUERTO RICO.

FOR THE REST OF THE WEEK...MAINLY PLEASANT WEATHER CONDITIONS ARE
EXPECTED...WITH THE CONTINUATION OF PASSING SHOWERS ACROSS THE
REGION. BY MID WEEK...AN UPPER LEVEL TROUGH IS FORECAST BY GFS
MODEL TO DEVELOPS ACROSS THE WESTERN ATLANTIC. THIS TROUGH IS
EXPECTED TO REMAIN AWAY FROM THE REGION.

&&

.AVIATION...PASSING SHOWERS IN AND AROUND A FEW TAF SITES EARLY
SUNDAY MORNING. WX CONDITIONS EXPECTED TO IMPROVE SUNDAY
MORNING...HOWEVER SHOWER DEVELOPMENT EXPECTED ONCE AGAIN IN THE
AFTERNOON CAUSING BRIEF MVFR CONDITIONS AT JMZ FROM 05/18Z THROUGH
05/22Z. OVERNIGHT...WINDS RANGING FROM LIGHT AND VARIABLE TO E NE
WINDS 10 KNOTS...INCREASING TO 10 TO 15 KNOTS BY LATE
MORNING...WITH ISOLATED GUSTS TO 20 KNOTS WITH AFTERNOON SHOWERS.

&&

.MARINE...SEAS UP TO 6 FEET AND WINDS UP TO 15 KNOTS ARE EXPECTED
OVER THE COASTAL WATERS. SMALL CRAFT SHOULD EXERCISE CAUTION.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 87 75 / 50 30 30 30
STT 85 75 85 75 / 50 30 50 50