THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


CARIBBEAN FORECAST DISCUSSION




TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
642 AM EDT WED APR 01 2015

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. BROAD
MID/UPPER LEVEL TROUGH IS TO DOMINATE PATTERN ACROSS THE NORTHERN
CARIBBEAN ISLES OVER THE NEXT FOUR DAYS...WITH AXIS TO GRADUALLY
STRENGTHEN THROUGH MIDDAY ON SATURDAY AS A RIDGE BUILDS TO THE
WEST. AS THE TROUGH ALOFT HOLDS...THIS IS TO STEER SHORT WAVE
VORTICES ACROSS THE FORECAST AREA...PROVIDING DYNAMICAL SUPPORT TO
CONVECTIVE DEVELOPMENT. TWO MAJOR PERTURBATIONS ARE OF CONCERN...
WITH ONE BY MIDDAY ON THURSDAY AND THE OTHER ON SATURDAY. ALTHOUGH
THE LATTER APPEARS STRONGER...BEST JET DYNAMICS ASSOCIATES WITH
THE ONE ON THURSDAY. AT LOW LEVELS...POLAR HIGH ROLLS TO THE
WESTERN ATLANTIC EARLY IN THE CYCLE...TIGHTENING THE GRADIENT
WHILE SUSTAINING A COOL ADVECTIVE PATTERN. FURTHERMORE...THIS IS
TO ALSO DRIVE A PREFRONTAL SHEAR LINE ACROSS PUERTO RICO TO THE
VIRGIN ISLES DURING THE DAY ON THURSDAY. AS A COOL NORTHEASTERLY
FLOW PERSISTS...THIS IS TO GENERALLY FAVOR GENERATION OF TRADE
WIND SHOWERS ACROSS THE NORTHEAST CARIBBEAN ISLES.

THIS PATTERN IS TO FAVOR AN INCREASE IN ACTIVITY ACROSS THE
FORECAST AREA...WITH SCATTERED CONVECTION EXPECTED ON THURSDAY AND
SATURDAY. IN A NORTHEASTERLY STEERING FLOW...THE MOST INTENSE IS
TO CLUSTER ACROSS SOUTHWEST AND WESTERN INTERIOR PORTIONS OF
PUERTO RICO. IN THIS AREA HIGH RESOLUTION WRF SHOWS MAXIMA OF 2-3
INCHES...AND THIS SEEMS REASONABLE WITH CURRENT ENVIRONMENTAL
CONDITIONS.

CRAIG...TTMS (TRINIDAD AND TOBAGO)
SAMUEL...MDS (SURINAME)
DAVISON...WPC (USA)




Last Updated: 642 AM EDT WED APR 01 2015