Prognostic Meteorological Discussion
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FXCA20 KWBC 081105
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
604 AM EST THU DEC 08 2016

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM DEC 08/06
UTC: AN EASTERLY WAVE ENTERS THE ISLAND CHAIN EARLY THIS
MORNING...WITH BEST MOISTURE CONVERGENCE TAKING PLACE JUST SOUTH
OF 16N. THE WAVE IS SLIDING UNDER A WANING MID LEVEL RIDGE THAT
EXTENDS OVER THE NORTHERN CARIBBEAN ISLANDS/WESTERN ATLANTIC. ON
FRIDAY THE WAVE IS TO STREAM SOUTH OF THE FORECAST AREA.
SIMULTANEOUSLY...THE MID LEVEL RIDGE WILL WEAKEN ENOUGH TO ALLOW
AN INCREASE IN PRECIPITABLE WATER CONTENT THAT IS TO FEED DIURNAL
CONVECTION LATER IN THE AFTERNOON AND DURING THE DAY ON SATURDAY.
IN A DEEP LAYER STEERING EASTERLY FLOW...EXPECTING LIGHT
CONVECTION ACROSS THE VIRGIN ISLES AND EASTERN PORTIONS OF PUERTO
RICO...WITH MEASURABLE AMOUNTS TO GENERALLY LIMIT TO WESTERN
INTERIOR PORTIONS OF PUERTO RICO. IN THIS AREA THE GFS AND UKMET
BOTH SHOW DAILY MAXIMA OF LESS THAN AN INCH...WITH THE NMM VERSION
OF THE HRWRF SHOWS LOCALIZED MAXIMA OF ONE-TO-TWO INCHES.

THE TRADE WINDS CAP IS TO RAPIDLY REESTABLISH ACROSS THE FORECAST
AREA ON SUNDAY TO MONDAY. THIS WILL BE ACCOMPANIED BY A TRADE
WINDS SURGE...WITH GFS SHOWING WINDS GRADUALLY INCREASING ON
SUNDAY TO AROUND 20-25KT LATER IN THE DAY/EARLY MONDAY MORNING.
THIS IS TO PERSIST THROUGH TUESDAY. THE STRONG WINDS WILL FAVOR
GENERATION OF STREAMERS ACROSS THE LEEWARD/VIRGIN ISLES THAT ARE
TO AFFECT EASTERN PORTIONS OF PUERTO RICO FROM TIME-TO-TIME...TO
RESULT IN LIGHT RAINFALL AMOUNTS IN PASSING SHOWERS. THE GLOBAL
MODELS ALSO SHOW PERIODS OF MODERATE CONVECTION AS CLOUD CLUSTERS
EMBED IN THE EASTERLY TRADES AND ADVECT ACROSS THE FORECAST AREA.
IN SHALLOW CONVECTION...THE DAILY MAXIMA WILL PEAK AT LESS THAN
HALF AN INCH.

JIMENEZ...IMN (COSTA RICA)
MIRANDA...INAMEH (VENEZUELA)
DAVISON/GALVEZ...WPC (USA)

$$





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