Prognostic Meteorological Discussion
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FXCA20 KWBC 271108
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
608 AM EST MON FEB 27 2017

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM FEB 27/06
UTC: FORECAST AREA IS UNDER INFLUENCE OF A BROAD CELL OF THE
SUBTROPICAL RIDGE...WITH MID/UPPER LEVEL AXIS EXTENDING
WEST-TO-EAST ACROSS THE NORTHERN CARIBBEAN ISLES. A TUTT LIES TO
THE EAST...CENTERING ON A CLOSED LOW EAST OF THE LEEWARD ISLES.
THESE FAVOR A MID/UPPER LEVEL CONVERGENT PATTERN THAT IS TRAPPING
MOISTURE TO THE LOW LEVELS OF THE ATMOSPHERE. AT LOW LEVELS...A
HIGH OVER MID ATLANTIC REGION OF THE USA ANCHORS A RIDGE OVER THE
WESTERN ATLANTIC. THIS FAVORS A FRESH EAST-NORTHEAST FLOW ACROSS
THE CARIBBEAN BASIN. A PERTURBATION IN THE EASTERLY TRADES EMBEDS
IN THIS FLOW... PULLING ACROSS THE VIRGIN ISLES-PUERTO RICO EARLY
THIS MORNING. THIS IS TO TRIGGER SHALLOW CONVECTION AS IT PULLS
ACROSS THE FORECAST AREA EARLY THIS MORNING. TRAILING MOISTURE IS
TO FAVOR ADDITIONAL SHOWERS ON TUESDAY...WHEN BOTH VERSIONS OF THE
HIGHER RESOLUTION MODEL GUIDANCE SHOW HIGHER RISK OF SHOWERS.

THE MID/UPPER LEVEL RIDGE IS TO HOLD DURING THE NEXT FEW DAYS.
ASSOCIATED CAP INVERSION IS FORECAST TO STRENGTHEN BY MIDWEEK.
THIS IS TO FAVOR A DRYING TREND ACROSS THE FORECAST AREA. AT LOW
LEVELS...HIGH/ RIDGE ARE TO SLOWLY YIELD TO POLAR FRONT EXITING
THE EASTERN USA LATER ON WEDNESDAY. AS THE HIGH RELOCATES...
PREVAILING EASTERLY TRADES ARE TO DOMINATE THE LOW LEVEL FLOW. AT
850 HPA THE WINDS ARE TO GENERALLY HOLD BETWEEN 20-25KT...WHICH IS
LIKELY TO FAVOR GENERATION OF STREAMERS ACROSS THE VIRGIN
ISLES-EASTERN PUERTO RICO. ASSOCIATED CONVECTION IS TO CLUSTER
ACROSS EASTERN PUERTO RICO/EL YUNQUE RAINFOREST...WITH SECONDARY
CONVECTION TO LIMIT TO WESTERN PUERTO RICO IN LATE AFTERNOON
CONVECTION

TROPICAL DISCUSSION FROM FEB 27/12 UTC:

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:
INITIAL   24     36     48     60     72     84     96    TYPE
NONE

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

$$




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