WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ..................................................................
TEMPERATURE (F) TODAY MAXIMUM 92 316 PM 94 2012 89 3 94 2005 MINIMUM 79 535 AM 70 1956 78 1 79 AVERAGE 86 83 3 87
PRECIPITATION (IN) TODAY 0.27 3.55 1965 0.15 0.12 0.00 MONTH TO DATE 5.57 2.35 3.22 T SINCE JUN 1 5.57 2.35 3.22 T SINCE JAN 1 30.10 21.03 9.07 25.55
Last Edit: Jun 15, 2013 19:29:52 GMT -6 by Deleted
Good morning. Hazy and dry weather will prevail today in PR and adjacent islands. A Tropical Wave will increase the showers by Wednesday.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 500 AM AST SUN JUN 16 2013
.SYNOPSIS...AT UPPER LEVELS...HIGH PRESSURE WILL SHIFT WEST TO THE CARIBBEAN SOUTH OF CUBA AS LOW PRESSURE DIGS SOUTH AND CUTS OFF JUST NORTH OF SAINT THOMAS DURING THE EARLY PART OF THE WEEK. WEAK LOW PRESSURE CONTINUES OVER THE GREATER ANTILLES KEEPING FLOW SOUTHWESTERLY DURING THE WEEK. HIGH PRESSURE RIDGES IN FROM THE TROPICAL ATLANTIC LATE IN THE WEEK.
AT MID LEVELS...LOW PRESSURE AND WEAK GRADIENTS PERSIST OVER AND TO THE NORTH OF THE AREA THROUGH MUCH OF THE WEEK. HIGH PRESSURE WILL RIDGE IN FROM THE EAST LATE IN THE WEEK. THE BEST MOISTURE OF WEEK WILL BE ON WEDNESDAY AND THURSDAY WHEN A TROPICAL WAVE COMES THROUGH.
AT LOWER LEVELS...HIGH PRESSURE CONTINUES OVER THE CENTRAL ATLANTIC THROUGHOUT THE WEEK WITH LOW PRESSURE IN THE SOUTHWEST CARIBBEAN. THIS WILL CONTINUE MODERATE TO FRESH TRADE WINDS FROM THE EAST SOUTHEAST. LOW LEVEL MOISTURE PERSISTS THROUGH MONDAY BUT REMAINS VERY SHALLOW. WINDS AT 850 MB INCREASE AND TURN SOUTHEAST AS A TROPICAL WAVE COMES THROUGH LATE ON WEDNESDAY. MOISTURE DECREASES FAIRLY RAPIDLY AFTER THAT BUT RETURNS BRIEFLY ON THE FOLLOWING SUNDAY.
&&
.DISCUSSION...ONLY SPRINKLES WERE OBSERVED OVERNIGHT AS ATMOSPHERE HAS TURNED MORE STABLE AND AIR ABOVE 6 KFT HAS BECOME SIGNIFICANTLY DRIER. PRECIPITABLE WATER AT SAINT CROIX DROPPED BELOW 1.5 INCHES. EVEN THE HIGHER CLOUDS ARE NOW LOCATED PREDOMINANTLY OVER HISPANIOLA. THIS WILL ALLOW GOOD PENETRATION OF THE SUNLIGHT AND FORCE A SEA BREEZE OVER THE LOCAL COASTLINES THAT WILL ALSO ACCELERATE THE TRADE WINDS NEAR SHORE. THEREFORE EXPECT MORE WIND TODAY THAN YESTERDAY. EXPECTED MORE SHOWER ACTIVITY YESTERDAY...BUT DRIER MID LEVELS AND CONSIDERABLE SAHARAN DUST GENERATED AFTERNOON SHOWERS ONLY IN A SMALL PORTION OF THE NORTHWEST. LITTLE HAS CHANGED TO BRING MORE ACTIVITY TODAY AND HAVE LEFT POPS QUITE LOW OVER THE AREA. IT APPEARS THAT THIS WILL CONTINUE UNTIL AROUND WEDNESDAY MORNING...WHEN A TROPICAL WAVE PUSHES THROUGH AND SHOWERS AND THUNDERSTORMS RETURN TO THE AREA. ALSO THE GFS IS SHOWING WINDS AT 850 MB EXCEEDING 35 KNOTS OVER SAN JUAN AND MUCH OF THE FORECAST AREA AFTER WEDNESDAY NOON. WITH SOMEWHAT DRY MID LAYERS THIS MAY CAUSE STRONG WINDS TO REACH THE SURFACE DURING SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT AND THURSDAY. GUSTS MAY REACH 45 MPH IN SOME AREAS SHOULD SHOWERS FORM AND MOVE THROUGH WITH ANY ORGANIZATION. DRIER WEATHER WILL RETURN ON FRIDAY AND SATURDAY.
&&
.AVIATION... VFR COND EXPECTED FOR NEXT 24 HOURS AT ALL SITES. HZ ASSOC WITH SAHARAN DUST WILL CAUSE SLIGHT VIS REDUCTION AT TIMES. WIND FROM SFC TO 2K FEET THRU SUNDAY GENERALLY FROM ESE AT 15-20 KT.
&&
.MARINE...SEAS CONTINUE 4 TO 6 FEET MOST EXPOSED WATERS WITH 15 TO 20 KNOT WINDS. SEAS MAY INCREASE TO 7 FEET WITH APPROACHING TROPICAL WAVE ON WEDNESDAY AND EXPECT SMALL CRAFT ADVISORIES TO BE NECESSARY.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 257 PM AST SUN JUN 16 2013
.SYNOPSIS...A GENERALLY STABLE WEATHER PATTERN IS EXPECTED TO PREVAIL ACROSS THE FORECAST AREA THROUGH AT LEAST TUESDAY. SAHARAN DUST WILL CONTINUE TO REACH THE NORTHEAST CARIBBEAN ISLANDS THROUGH AT LEAST MIDWEEK...PRODUCING HAZY SKIES AND SOME AREAS OF REDUCED VISIBILITIES. WEATHER CONDITIONS WILL CHANGE BY MIDWEEK WHEN THE NEXT TROPICAL WAVE AND ITS ASSOCIATED MOISTURE WILL MOVE OVER THE AREA...INCREASING THE CLOUD AND SHOWER COVERAGE ACROSS THE ISLANDS.
&&
.DISCUSSION...VISIBLE SATELLITE IMAGERY HAVE BEEN SHOWING SAHARAN DUST PARTICLES SUSPENDED IN THE AIR OVER THE NORTHEAST CARIBBEAN. THE ABUNDANT DUST ON THE AIR HAS PRODUCED HAZY SKIES IN ALL THE LOCAL ISLANDS TODAY. THE 16/12Z TJSJ SOUNDING SUGGEST THAT MOST OF THE DUST PARTICLES ARE SUSPENDED IN A LAYER BETWEEN 5-20 KFT OR BETWEEN 850-500 MB. ALSO...IN THE 12Z TJSJ SOUNDING SHOWED AN INVERSION AROUND 4500 FT...SUGGESTING THAT A RELATIVELY DRY AND STABLE AIR MASS ACCOMPANIES THESE DUST PARTICLES. LATEST SATELLITE PWAT ANALYSIS SHOWED PRECIPITABLE WATER VALUES OF ABOUT 15-25 PERCENT BELOW NORMAL FOR THIS TIME OF THE YEAR. ISOLATED SHOWERS AND THUNDERSTORMS ARE STILL POSSIBLE OVER NORTHWESTERN PR...HOWEVER... THE CHANGE OF RAIN IS LOW FOR THE REST OF PR AND THE ADJACENT ISLANDS TODAY. ANOTHER POSSIBILITY IS THAT THE TRADE WINDS MAY CARRY A FEW LIGHT SHOWERS OVER WINDWARD SIDE OF THE ISLANDS... ESPECIALLY LATE AT NIGHT AND EARLY IN THE MORNING. SINCE THE PW VALUES WILL REMAIN SLIGHTLY BELOW NORMAL UNTIL TUESDAY...NO SIGNIFICANT HEAVY RAIN OR FLOODING PROBLEMS ARE ANTICIPATED.
THE FORECAST MODELS SHOW SURFACE HIGH PRESSURE WILL REMAIN FAR NORTHEAST OF THE ISLANDS FOR THE NEXT FEW DAYS...WHICH WILL MAINTAIN THE MODERATE TO LOCALLY FRESH LOW-LEVEL TRADE WIND FLOW ACROSS THE LOCAL REGION INTO MID-WEEK. WEATHER CONDITIONS WILL CHANGE ON WEDNESDAY WHEN A TROPICAL WAVE APPROACHES FROM THE SOUTHEAST... INCREASING THE CHANGES OF SHOWERS AND THUNDERSTORMS ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS. IN TERMS OF THE HAZY CONDITIONS... NAAPS AEROSOL MODEL CONTINUES TO FORECAST DECENT AMOUNT OF SAHARAN DUST THROUGH AT LEAST NEXT FRIDAY.
&&
.AVIATION...VFR ALL SITES THRU MON THO HZ FROM SAHARAN DUST TO REDUCE VSBY A BIT. STREAMERS WL CAUSE LCL CIGS W OF ISLANDS NXT FEW HRS...AND ISOLD SHRA NR TJMZ. WIND BLO FL150 ESE 15-27 KT BCMG E TONITE.
&&
.MARINE...LITTLE CHANGE THRU MON WITH SEAS UP TO 6 FEET AND WIND 20 KT OR UNDER. SEAS AND WINDS WILL INCREASE SLIGHTLY LATE TUESDAY AND WEDNESDAY AS THE TROPICAL WAVE MOVES ACROSS THE LOCAL WATERS. SCA WILL BE POSSIBLE LATE TUESDAY THROUGH AT LEAST THURSDAY DUE TO SEAS AROUND 7 FEET AND FRESH TO LOCALLY STRONG WINDS.
.THE SAN JUAN/P.R. CLIMATE SUMMARY FOR JUNE 16 2013... VALID TODAY AS OF 0500 PM LOCAL TIME.
CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1898 TO 2013
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL .................................................................. TEMPERATURE (F) TODAY MAXIMUM 87 159PM 96 1983 89 -2 92 MINIMUM 78 635AM 70 1957 78 0 79 AVERAGE 83 83 0 86
PRECIPITATION (IN) TODAY 0.00 1.97 2011 0.14 -0.14 0.01 MONTH TO DATE 5.57 2.49 3.08 0.01 SINCE JUN 1 5.57 2.49 3.08 0.01 SINCE JAN 1 30.10 21.17 8.93 25.56...
Last Edit: Jun 16, 2013 21:28:58 GMT -6 by Deleted
Good morning. A Tropical Wave interacting with a trough will cause scattered showers starting on Wednesday.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 520 AM AST MON JUN 17 2013
.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE WILL CUT OFF NORTH OF PUERTO RICO AND COME TO WITHIN 320 MILES OF THE ISLANDS BY TUESDAY EVENING. LOW PRESSURE WILL THEN PULL NORTH SOMEWHAT BUT REMAIN NEARBY THROUGH THE WEEKEND.
AT MID LEVELS...THE TROUGH OVER THE LOCAL AREA WILL DRIFT WEST DURING THE WEEK THEN RE-FORM NORTH OF PUERTO RICO OVER THE WEEKEND. MOISTURE IS SPARSE UNTIL A TROPICAL WAVE PASSES BY WEDNESDAY THROUGH THURSDAY.
AT LOWER LEVELS...HIGH PRESSURE AT THE SURFACE WILL DOMINATE THE CENTRAL ATLANTIC WITH A RIDGE EXTENDING ACROSS FLORIDA OR GEORGIA FOR MOST OF THE NEXT 10 DAYS. LOW PRESSURE WILL CONTINUE IN THE SOUTHERN CARIBBEAN AND GENERATE MODERATE TO FRESH EAST SOUTHEAST TRADE WINDS. A TROPICAL WAVE NEAR 53 DEGREES WEST LONGITUDE WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY THROUGH THURSDAY WITH SHOWERS AND THUNDERSTORMS. ANOTHER TROUGH WILL PASS THROUGH SATURDAY NIGHT.
&&
.DISCUSSION...FEW SHOWERS OCCURRED OVERNIGHT...BUT A LITTLE MORE SHOWER ACTIVITY WAS OCCURRING NORTH AND SOUTH OF VIEQUES BY 5 AM AST. A FEW OF THESE SHOWERS WILL COME ONSHORE IN EASTERN PUERTO RICO BUT RAIN AMOUNTS WILL BE SLIGHT. DRY MID LAYERS AND SLIGHTLY BELOW NORMAL PRECIPITABLE WATER CONTINUE TODAY AND EXPECT SHOWER ACTIVITY TO BE SIMILAR TO SUNDAY WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN WESTERN PUERTO RICO. EXPECT A LITTLE MORE ACTIVITY ON TUESDAY AS THE TROPICAL WAVE APPROACHES BUT MAIN ACTIVITY SHOULD NOT HAPPEN UNTIL WEDNESDAY AFTERNOON. BEST DIVERGENCE ALOFT DUE TO THE INTERACTION OF THE WAVE WITH THE UPPER LEVEL LOW WILL NOT OCCUR UNTIL 20/06Z AND MAY NOT COINCIDE WITH WAVE PASSAGE AND AFTERNOON HEATING MAXIMUM FOR MORE ENHANCED ACTIVITY...BUT MOISTURE AND GOOD DYNAMICS PERSIST UNTIL AT LEAST 20/18Z AND SOME SHOWERS MAY PERSIST FOR A GOOD DEAL OF WEDNESDAY NIGHT OVER PUERTO RICO. IN THE 00Z RUN OF THE GFS WINDS AT 850 MB INCREASE TO 30 TO 35 KNOTS AT 19/18Z. THIS IS DOWN FROM THE 16/18Z MODEL RUN WHICH SHOWED UP TO 40 KNOTS OVER THE LOCAL AREA ON 20/06Z. THIS WOULD BE OF SOME CONCERN SINCE THUNDERSTORMS MOVING AT NO MORE THAN 15 KNOTS COULD PRODUCE GUSTS OF UP TO 50 KNOTS IN ISOLATED AREAS SHOULD THEY BECOME STRONG ENOUGH. LIFTED INDICES OF -5 TO -7 ARE EXPECTED BETWEEN NOW AND WEDNESDAY AFTERNOON. BEST CAPE IS ABOUT 3250 BUT OCCURS ON TUESDAY...AND BULK RICHARDSON NUMBER RELATIVELY HIGH AND MAY NOT SUPPORT WELL ORGANIZED DOWNDRAFT ACTIVITY. WITH SLIGHT DOWNWARD TREND IN THE FORECAST...WILL SAY THAT SOME THUNDERSTORMS COULD CONTAIN GUSTS APPROACHING SEVERE LIMITS. WEATHER FOR THE REMAINDER OF THE WEEK AND THE UPCOMING WEEKEND LOOKS LESS ACTIVE...BUT WOULD EXPECT SHOWERS AND THUNDERSTORMS IN THE INTERIOR OF PUERTO RICO EACH DAY.
&&
.AVIATION...VFR COND FOR ALL SITES THRU MON...THOUGH HZ FROM SAHARAN DUST WILL AFFECT VSBY. WIND SFC TO 2K FT ESE 15-20 KT BCMG GENERALLY FROM E.
&&
.MARINE...SEAS WERE BELOW 6 FEET EARLY THIS MORNING AT BUOY 41043 AND MODEL SHOWS LITTLE INCREASE UNTIL WEDNESDAY. THEREFORE EXPECT NO SMALL CRAFT ADVISORIES UNTIL WEDNESDAY. NEVERTHELESS SEAS OF 4 TO 6 FEET OR WINDS UP TO 20 KTS MAY BE EXPECTED THROUGH TUESDAY. THUNDERSTORMS WITH THE WAVE ON WEDNESDAY AND THURSDAY MAY HAVE VERY STRONG WIND GUSTS DUE TO DRY AIR AND WINDS OF UP TO 30 KNOTS IN THE LAYER FROM 700 TO 1000 MB.
Tropical Wave will arrive on Wednesday bringing scattered showers.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 236 PM AST MON JUN 17 2013
.SYNOPSIS...AN UPPER LEVEL TROUGH NORTH NORTHWEST OF THE REGION WILL EVOLVE INTO A CUT OFF LOW TONIGHT. THIS FEATURE IS EXPECTED TO MEANDER NORTH OF THE REGION UNTIL AT LEAST THURSDAY. A GENERALLY FAIR AND STABLE WEATHER PATTERN IS EXPECTED TO PREVAIL ACROSS THE FORECAST AREA THROUGH AT LEAST WEDNESDAY. SAHARAN DUST WILL CONTINUE ACROSS THE NORTHEAST CARIBBEAN THROUGH MIDWEEK. WEATHER CONDITIONS WILL CHANGE WEDNESDAY AND THURSDAY WHEN THE NEXT TROPICAL WAVE AND ITS ASSOCIATED MOISTURE APPROACHES THE AREA.
&&
.DISCUSSION...THE DOPPLER WEATHER RADAR INDICATED ONLY ISOLATED SHOWER ACTIVITY MAINLY ACROSS THE SURROUNDING COASTAL WATERS WITH MINIMAL SHOWERS OVER LAND AREAS DURING THE LATE MORNING HOURS...AS A STRONG SURFACE HIGH ACROSS THE CENTRAL ATLANTIC CONTINUES TO DOMINATE THE WEATHER PATTERN ACROSS THE LOCAL ISLANDS. FEW SHOWERS ALSO DEVELOPED ACROSS WESTERN AND INTERIOR SECTIONS OF PUERTO RICO EARLY IN THE AFTERNOON BUT THIS ACTIVITY WAS SHORT-LIVE AND DISSIPATED RAPIDLY. TJSJ 17/12 SOUNDING INDICATED A MODERATE PWAT VALUE OF 1.74 INCHES. A SIMILAR WEATHER PATTERN AS TODAY IS EXPECTED FOR TOMORROW AFTERNOON. A SAHARAN AIR LAYER WILL CONTINUE ACROSS THE REGION UNTIL AT LEAST WEDNESDAY. THIS FEATURE WILL CONTINUE TO SUPPRESS THE DEVELOPMENT OF SIGNIFICANT CONVECTION UNTIL THE MIDDLE OF THE WEEK. EXPECT AN INCREASE IN CLOUDINESS AND SHOWER ACTIVITY WEDNESDAY AND THURSDAY AS THE TROPICAL WAVE...ALONG 58 WEST THIS AFTERNOON...APPROACHES TO THE LOCAL ISLANDS. LATEST SATELITE IMAGES AND COMPUTER MODEL GUIDANCE SUGGEST THAT THE BULK OF THE CONVECTION ASSOCIATED WITH THIS WAVE WILL PASS WELL SOUTH OF THE LOCAL ISLANDS.
&&
.AVIATION...VFR THRU TUE XCP IN AFT NR ISOLD/SCT SHRA/TSRA OVR INTERIOR/WEST PR WI MTN OBSC. WIND BLO FL150 E 15-30 KT THRU TUE. SAHARAN DUST AT TIMES TO CAUSE SLGTLY LWR VSBY.
&&
.MARINE...SEAS CONTINUE IN THE ORDER OF 4 TO 6 FT AND WINDS UP TO 20 KT THROUGH AT LEAST TUE. SMALL CRAFT ARE URGED TO EXERCISE CAUTION ACROSS ALL OF THE LOCAL COASTAL WATERS. A TROPICAL WAVE WILL MOVE ACROSS THE WINDWARD ISLANDS TONIGHT AND WILL AFFECT PR/USVI WED AND THU.
...THE SAN JUAN/P.R. CLIMATE SUMMARY FOR JUNE 17 2013... VALID TODAY AS OF 0500 PM LOCAL TIME.
CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1898 TO 2013
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL .................................................................. TEMPERATURE (F) TODAY MAXIMUM 87 314 PM 94 2005 89 -2 92 MINIMUM 80 626 AM 70 1960 78 2 80 AVERAGE 84 83 1 86
PRECIPITATION (IN) TODAY 0.00 2.45 1960 0.15 -0.15 0.01 MONTH TO DATE 5.57 2.64 2.93 0.02 SINCE JUN 1 5.57 2.64 2.93 0.02 SINCE JAN 1 30.10 21.32 8.78 25.57
Still the Tropical Wave is slated to arrive by Wednesday.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 1019 PM AST MON JUN 17 2013
.UPDATE...FORECAST ON TRACK. A GENERALLY FAIR WEATHER PATTERN WILL CONTINUE TO PREVAIL AT LEAST THROUGH MIDWEEK WITH SHALLOW AFTERNOON CONVECTION POSSIBLE EACH DAY ACROSS WESTERN PUERTO RICO. A BETTER CHANCE FOR SHOWER AND THUNDERSTORM ACTIVITY EXPECTED WEDNESDAY MORNING AS TROPICAL WAVES MOVES OVER THE LOCAL AREA. HOWEVER... BEHIND AFOREMENTIONED TROPICAL WAVE A DRIER AND STABLE AIR MASS IS EXPECTED TO ESTABLISH.
&&
.AVIATION...VFR COND WILL CONTINUE XCP IN TUE AFT WHERE ISOLD/SCT SHRA AND ISOLD TSRA OVR INTERIOR/WEST PR WI MTN OBSC IS POSSIBLE. WIND SFC TO 2K FT GENERALLY FROM EAST AT 10-20 KT. SAHARAN DUST AT TIMES TO CAUSE SLGTLY LWR VSBY.
&&
.MARINE...NO CHANGE TO PREVIOUS DISCUSSION. SMALL BOAT OPERATORS SHOULD EXERCISE CAUTION DUE TO SEAS OF UP TO 6 FEET AND WINDS 21 KNOTS OR LESS. SEAS AND WINDS EXPECTED TO INCREASE ON WEDNESDAY AS TROPICAL WAVE MOVES OVER THE LOCAL AREA.
Good morning. A Tropical Wave interacting with an upper trough will bring scattered showers to PR and adjacent islands starting on Wednesday.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 520 AM AST TUE JUN 18 2013
.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE IS ABOUT 290 MILES NORTH OF SAINT THOMAS AND WILL MOVE NORTH AND SLIGHTLY WEST DURING THE NEXT 48 HOURS WITH TROUGHING EXTENDING OVER HISPANIOLA. THIS LOW WILL MOVE EAST OVER THE WEEKEND WHILE HIGH PRESSURE RIDGES INTO THE SOUTHEASTERN CARIBBEAN. BY MID WEEK NEXT WEEK A RIDGE WILL HAVE BUILT INTO THE WESTERN CARIBBEAN AND EXTEND NORTH TO FLORIDA.
AT MID LEVELS...A WEAK TROUGH OVER AND NORTH OF THE AREA WILL MOVE SLOWLY WEST AND WEAKEN ONLY TO RE-FORM OVER THE WEEKEND NORTH OF THE AREA. LOWER PRESSURE WILL REMAIN ENSCONCED TO THE NORTHEAST OF PUERTO RICO THROUGH THE END OF NEXT WEEK.
AT LOWER LEVELS...HIGH PRESSURE WILL CONTINUE OVER THE CENTRAL ATLANTIC THROUGH MID WEEK NEXT WEEK WHILE LOW PRESSURE REMAINS IN THE SOUTHWESTERN CARIBBEAN. THIS WILL KEEP MODERATE TO FRESH TRADE WINDS OVER THE LOCAL AREA THROUGH THE ENTIRE FORECAST PERIOD. A TROPICAL WAVE WILL MOVE THROUGH THE AREA WEDNESDAY AND WEDNESDAY NIGHT WITH SOME RAIN...AND THUNDERSTORMS WITH VERY GUSTY WINDS.
&&
.DISCUSSION...AGAIN VERY FEW SHOWERS WERE SEEN OVERNIGHT IN RELATIVELY BRISK EASTERLY TRADE WIND FLOW. DUST FROM THE SAHARA WILL PERSIST TODAY AND TONIGHT...BUT WITH THE COMING TROPICAL WAVE SURFACE VISIBILITIES WILL IMPROVE SOMEWHAT. MOISTURE OVER THE LOCAL AREA REACHED A MINIMUM OVERNIGHT AND WILL BEGIN TO RECOVER...TO AS MUCH AS 2 INCHES BY 19/18Z. MOISTURE OVER SAINT CROIX IS ALREADY APPROACHING 1.7 INCHES. THIS HERALDS THE TROPICAL WAVE THAT WILL APPROACH ON WEDNESDAY WITH A DOUBLE TROUGH AT 700 MB. THE FIRST TROUGH WILL PASS OVER PUERTO RICO AT ABOUT 19/12Z WHILE THE SECOND AND STRONGER TROUGH WILL MOVE THROUGH BETWEEN 20/06 AND 20/12Z. THIS WAVE IS ACCOMPANIED BY A VERY STRONG SOUTHEAST WIND SURGE OF BETWEEN 925 AND 700 MB...WHICH ON WEDNESDAY NIGHT WILL REACH 40 KNOTS ACCORDING TO THE GFS AND CONFIRMED BY THE WRF AND NMM MODELS IN BOTH THE 17/18Z AND 18/00Z GFS RUNS. ANY THUNDERSTORMS THAT FORM IN THIS ENVIRONMENT WILL BE LIKELY TO HAVE VERY STRONG GUSTS WHICH COULD...IN A FEW PLACES...EXCEED SEVERE LIMITS...ESPECIALLY IN THE CARIBBEAN WATERS. BECAUSE MOISTURE IN THE LOWER LEVELS IS LIMITED AND FOLLOWED IMMEDIATELY BY MORE SAHARAN AIR...HEAVY RAIN WILL LIKELY BE LIMITED IN COVERAGE...AND FLOODING...EXCEPT FOR LOCAL DRAINAGE PROBLEMS...IS NOT EXPECTED WITH THIS WAVE. MOISTURE REACHES A MINIMUM ON FRIDAY EVENING AFTER THE WAVE PASSES SIMILAR TO THE ONE THAT JUST OCCURRED. AT THAT TIME WINDS WILL ABATE AND SHOWERS WILL DIMINISH CONSIDERABLY. A SECOND PULSE OF MOISTURE DEVELOPS EAST OF THE LEEWARD ISLANDS THURSDAY NIGHT AND MOVES ACROSS THE LOCAL AREA SATURDAY NIGHT.
&&
.AVIATION...VFR COND WILL CONTINUE XCP ON TUE AFTERNOON WHERE ISOLD/SCT SHRA AND ISOLD TSRA OVR INTERIOR/WEST PR WI MTN OBSC ARE POSSIBLE. WIND SFC TO 2K FT GENERALLY FROM EAST AT 10-20 KT. SAHARAN DUST AT TIMES TO CAUSE SLIGHTLY LWR VSBY.
&&
.MARINE...WINDS OF 16 TO 20 KNOTS HAVE ALREADY BROUGHT SEAS OF 4 TO 6 FEET ACROSS THE LOCAL EXPOSED WATERS. WINDS WILL BEGIN TO INCREASE ON WEDNESDAY AHEAD OF A TROPICAL WAVE. SUSTAINED WINDS WILL LIKELY REACH 20 TO 25 KNOTS...LOCALLY 30 KNOTS...WEDNESDAY AFTERNOON BEGINNING IN THE SOUTHEAST CORNER OF THE FORECAST AREA. GUSTS IN AND NEAR THUNDERSTORMS HAVE THE POTENTIAL TO REACH 45 KNOTS IN A FEW PLACES WEDNESDAY AFTERNOON AND EVENING.
Good afternoon. Wave moves thru on Wednesday bringing scattered showers. After wave passes,a big sal event will arrive bringing the dust.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 258 PM AST TUE JUN 18 2013
.DISCUSSION...UPPER TROPOSPHERIC TROUGH CURRENTLY NORTH OF PR/USVI ABOUT 22.5N SLOWLY DRIFTING WEST WILL INTERACT WITH A BROAD TROPICAL WAVE CURRENTLY EAST OF THE ANTILLES...MOVING WEST AT 25 KNOTS. IT IS ALREADY BEGINNING TO DRAW MOISTURE NORTHWARD AND AMPLIFY THE WAVE. SEVERAL THUNDERSTORM CLUSTERS ACROSS THE CARIBBEAN ARE PRODUCING OUTFLOW BOUNDARIES MOVING ALONG AT 30 KNOTS. EAST OF THE LEEWARDS AT 17Z-18Z A SHIP AND NEAR SURFACE GOES SATELLITE WINDS WERE REPORTING 25-28 KT. THESE ARE CONCERN ENOUGH TO KICK UP THE WINDS AND SEAS BY WED A LITTLE WHICH INCREASES THE COVERAGE OF THE SMALL CRAFT ADVISORY. ALSO 12Z GFS PUSHES 850-700 MB WINDS EXCEEDING 35 KT OVER TO NORTHEAST OF PR/USVI BY LATE WED. THIS IN ADDITION TO THE OUTFLOW BOUNDARIES ALREADY BEING GENERATED SUGGEST STRONG WIND GUSTS ARE POSSIBLE IN STRONG SHOWERS/THUNDERSTORMS.
DO NOT BELIEVE THAT SIGNIFICANT FLOODING WILL BE A THREAT SINCE GROUND IS RELATIVELY DRY AND THIS WAVE IS MOVING QUICKLY. HOWEVER MUST ESPECIALLY WATCH THE SOUTHEAST PR COAST AS ONSHORE FLOW COULD CAUSE PERSISTENT HEAVY SHOWERS THERE...MOST LIKELY WED EVENING.
DRYING TO OCCUR THU MORNING AND WE RETURN TO RATHER DRY CONDITIONS WITH SIGNIFICANT SAHARAN DUST.
&&
.AVIATION...VFR MOST OF TONITE BUT SHRA/TSRA TO INCR LATE AND INTO WED. SHRA/TSRA LATE THIS AFTERNOON NR TJMZ WL CAUSE PDS MVFR MAYBE IFR...OBSCD MTNS IN WEST PR. WIND BLO FL100 E 15-30 KT BCMG ESE 20-35 KT WED AFT.
&&
.MARINE...WINDS/SEAS INCREASING SLIGHTLY THROUGH WED BUT BIGGER CONCERN IS POSSIBLE HIGHER CONDITIONS IN/NEAR SHOWERS/THUNDERSTORMS ON WED/WED NIGHT. GUSTS TO 35-40 KT WILL BE POSSIBLE.
THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN
* URBAN AND SMALL STREAM FLOOD ADVISORY FOR THE FOLLOWING MUNICIPALITIES...
IN PUERTO RICO ANASCO...LARES...MARICAO...LAS MARIAS...AGUADA AND MAYAGUEZ
* UNTIL 545 PM AST
* AT 345 PM AST...DOPPLER RADAR INDICATED SHOWERS AND THUNDERSTORMS AFFECTING THE ADVISORY AREA. THIS SHOWER ACTIVITY WILL BRING RAINFALL AMOUNTS BETWEEN 1 AND 2 INCHES IN SOME AREAS. THIS ADDITIONAL RAINFALL WILL RESULT IN PONDING OF WATER IN URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE AREAS AND LOW LYING SPOTS.
MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.
...THE SAN JUAN/P.R. CLIMATE SUMMARY FOR JUNE 18 2013... VALID TODAY AS OF 0500 PM LOCAL TIME.
CLIMATE NORMAL PERIOD 1981 TO 2010 CLIMATE RECORD PERIOD 1898 TO 2013
WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL .................................................................. TEMPERATURE (F) TODAY MAXIMUM 88 216 PM 94 2005 89 -1 90 1983 MINIMUM 79 534 AM 69 1909 78 1 80 AVERAGE 84 83 1 85
PRECIPITATION (IN) TODAY 0.00 2.32 1949 0.14 -0.14 0.00 MONTH TO DATE 5.57 2.78 2.79 0.02 SINCE JUN 1 5.57 2.78 2.79 0.02 SINCE JAN 1 30.10 21.46 8.64 25.57
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