Prognostic Meteorological Discussion
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000
FXCA20 KWBC 281052
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
552 AM EST TUE FEB 28 2017

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM FEB 28/06
UTC: A 500 HPA HIGH OVER THE YUCATAN PENINSULA ANCHORS A MID LEVEL
RIDGE OVER CENTRAL AMERICA-CARIBBEAN BASIN. AS THE RIDGE
HOLDS...IT IS TO STEER AN UPPER LEVEL TROUGH ACROSS THE WESTERN
ATLANTIC INTO THE FORECAST AREA LATER ON WEDNESDAY.
THIS...HOWEVER... WILL NOT BE STRONG ENOUGH TO BREECH THE CAP
INVERSION ENVELOPING THE FORECAST AREA. AS THE TROUGH MOVES
EAST...CONVERGENCE/SUBSIDENCE ALOFT IS TO STRENGTHEN. THIS WILL
HELP SUSTAIN THE CAP INVERSION FOR THE REST OF THE WEEK. AT LOW
LEVELS...BERMUDA RIDGE DOMINATES THE FLOW ACROSS THE WESTERN
ATLANTIC...FAVORING BRISK EASTERLY TRADES ACROSS THE CARIBBEAN. A
WEEK PERTURBATION EMBEDS IN THE EASTERLY TRADES...AND THIS IS TO
MOVE ACROSS THE VIRGIN ISLES TO PUERTO RICO DURING THE DAY TODAY.
PATCHY CLOUDS ACCOMPANY THIS PERTURBATION...WITH HIGH RESOLUTION
MODEL GUIDANCE SHOWING POTENTIAL FOR MODERATE CONVECTION
CLUSTERING ALONG THE CORDILLERA LATER THIS MORNING/AFTERNOON
HOURS...SHOWING LOCALIZED MAXIMA OF A COUPLE INCHES.

POLAR FRONT EXITING THE EASTERN USA EARLY ON THURSDAY MORNING WILL
THEN PRESS AGAINST THE BERMUDA RIDGE. UNDER PRESSURE...THE HIGH
WILL RELOCATE TO THE CENTRAL ATLANTIC. AS THE HIGH/RIDGE ROLLS
AWAY...AND PRESSURE GRADIENT SLACKENS...THE EASTERLY TRADES WILL
GRADUALLY DROP FROM 20-25KT TO 10-15KT LATER ON THURSDAY/FRIDAY
MORNING. MEANWHILE...THE BRISK EASTERLY TRADES ARE TO FAVOR
GENERATION OF STREAMERS ACROSS THE NORTHERN LEEWARD/VIRGIN ISLES
THAT ARE TO AFFECT EASTERN PORTIONS OF PUERTO RICO FROM
TIME-TO-TIME. AFTERNOON CONVECTION IS ALSO EXPECTED ACROSS WESTERN
PUERTO RICO AS ENHANCED BY DIURNAL HEATING. AS THE TRADES SLACKEN
LATER IN THE WEEK...SEA BREEZE CONVERGENCE WILL THEN PREVAIL.

JIMENEZ...IMN (COSTA RICA)
SUBRATH-ALI...TTMS (TRINIDAD AND TOBAGO)
GALVEZ/DAVISON...WPC (USA)

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