Prognostic Meteorological Discussion
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FXCA20 KWBC 061148
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
648 AM EST FRI MAR 06 2015

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. STRONG
MID/UPPER LEVEL RIDGE CONTINUES TO DOMINATE FLOW ACROSS THE
WESTERN ATLANTIC-NORTHERN CARIBBEAN ISLANDS. THIS SUSTAINS A
SUBSIDENCE PATTERN AND CAP INVERSION THAT ARE FORECAST TO HOLD
THROUGH THE MEDIUM RANGE PERIOD...TRAPPING MOISTURE TO ATMOSPHERE
BELOW 750/800 HPA WHILE ALSO FAVORING A PWAT MINIMA ACROSS THE
FORECAST AREA. AT LOW LEVELS...A BROAD RIDGE EXTENDS FROM THE
CENTRAL TO WESTERN ATLANTIC...WITH POLAR TROUGH OVER THE EASTERN
USA SLOWLY LIFTING OVER THIS AXIS. ALTHOUGH SURFACE FRONT IS TO
REMAIN FAR TO THE NORTH...AS IT RIDES OVER THE RIDGE IT WILL LEAD
TO THE RAPID EROSION OF THIS AXIS EARLY IN THE CYCLE. ALTHOUGH
EASTERLY TRADES ARE TO PREVAIL...AS THE GRADIENT SLACKENS...THE
INTENSITY OF THE 900/850 HPA WINDS DECREASES TO 15-20KT EARLY IN
THE CYCLE...AND THIS IS TO PREVAIL THROUGH THE WEEKEND. MODELS
AGREE ON A PWAT MINIMA THROUGH SUNDAY...WITH MOISTURE CONTENT
SURGING ON MONDAY TO TUESDAY AS A PERTURBATION IN THE EASTERLY
TRADES STREAMS ACROSS THE FORECAST AREA.

IN THIS PATTERN...EXPECTING MOSTLY FAIR WEATHER CONDITIONS ACROSS
THE FORECAST AREA THROUGH SUNDAY EVENING...WITH LIGHT/BRIEF EARLY
MORNING SHOWERS TO PESTER THE VIRGIN ISLES-COASTAL WATERS OF
PUERTO RICO FROM TIME-TO-TIME. GLOBAL AND HIGH RESOLUTION MODELS
GENERALLY AGREE ON TRACE AMOUNTS OVER THE NEXT THREE DAYS.
MEASURABLE AMOUNTS...HOWEVER...ARE EXPECTED LATER ON
MONDAY-WEDNESDAY AS DEEPER MOISTURE ENTERS THE FORECAST AREA.

DISCUSSION FROM MARCH 06/00UTC:


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

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





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