Prognostic Meteorological Discussion
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
705 AM EST MON JAN 26 2015

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. AMPLIFYING
POLAR TROUGH DOMINATES THE EASTERN USA-GULF OF MEXICO...WITH
ASSOCIATED FRONT SURGING ACROSS THE EASTERN USA-FLORIDA PENINSULA
TO THE GULF OF MEXICO. THERE IS ALSO AN OLD/WANING FRONT TO THE
SOUTH AND EAST THAT EXTENDS ACROSS CENTRAL BAHAMAS-CUBA. IN
RESPONSE TO DEEP POLAR TROUGH PATTERN TO THE NORTH...AND
INDUCED/INVERTED TROUGH EXTENDS NORTH ACROSS THE CENTRAL CARIBBEAN
TO HAITI. THIS TROUGH SUSTAINS A MOIST SOUTHEASTERLY FLOW ACROSS
THE EASTERN CARIBBEAN ISLES...WITH MOISTURE CONVERGING OVER THE
WINDWARD/FRENCH ISLES EARLY THIS MORNING.

AMPLIFYING POLAR TROUGH ALOFT IS TO CONTINUE DEEPENING THROUGH
TUESDAY EVENING...WHEN IT IS TO EXTEND BETWEEN 100W-60W AND TO THE
NORTH OF 17N. IT IS TO THEN SLOWLY PULL TO THE EAST-NORTHEAST
LATER IN THE WEEK. AS THE TROUGH DEEPENS...SUBEQUATORIAL RIDGE
OVER THE CARIBBEAN IS TO COLLAPSE AND THE TRADE WINDS CAP IS TO
WEAKEN. AT LOW LEVELS...FRONT EMERGING OVER THE EASTERN USA IS TO
GRADUALLY MERGE WITH OLD BOUNDARY TO THE SOUTH AS THE LATTER
MEANDERS ACROSS THE BAHAMAS. THIS BOUNDARY IS TO THEN MOVE SOUTH
INTO HISPANIOLA LATER ON WEDNESDAY EARLY ON THURSDAY MORNING. AS
THE FRONT MOVES EAST...INDUCED/INVERTED TROUGH TO THE SOUTH IS TO
GRADUALLY RELOCATE TO THE EASTERN CARIBBEAN LATER ON WEDNESDAY
EVENING...TO ENHANCE MOISTURE TRANSPORT/CONVERGENCE ACROSS THE
FORECAST AREA. PREFRONTAL SHEAR LINE IS TO THEN MOVE ACROSS PUERTO
RICO/VIRGIN ISLES DURING THE DAY ON THURSDAY...WHERE IT IS TO
REMAIN THROUGH MIDDAY ON FRIDAY.

MOIST SOUTHEASTERLY FLOW AND WANING TRADE WINDS CAP TRANSLATES TO
MORE ACTIVE CONVECTION ACROSS THE FORECAST AREA OVER THE NEXT FEW
DAYS. CLOUD CLUSTER OVER THE FRENCH ISLES WILL BE THE FIRST
SALVO...WITH MODEL SHOWING MOISTURE QUICKLY LIFTING ACROSS THE
EASTERN CARIBBEAN TO PUERTO RICO AND THE VI LATER THIS AFTERNOON.
THE GFS SEEMS TO HAVE A BETTER HANDLE OF THIS SITUATION THAN THE
OTHER MODELS...PROPERLY INITIALIZING THE DEEP CLOUD CLUSTER AND
ASSOCIATED CONVECTION. THE EUROPEAN AND HIGH RESOLUTION MODELS
ONLY SHOW LIGHT RAINFALL AMOUNTS OVER THE NEXT TWO DAYS...AS THEY
POORLY INITIALIZE AVAILABLE MOISTURE. MODERATE TO HEAVY RAINFALL
AMOUNTS ARE LIKELY ON TUESDAY...AS PERSISTENT SOUTHEASTERLY FLOW
ENHANCES MOISTURE CONVERGENCE ACROSS NORTHWEST PORTIONS OF PUERTO
RICO. DEEPER MOISTURE IS EXPECTED LATER ON THURSDAY-FRIDAY AS
INVERTED TROUGH SETTLES OVER THE EASTERN CARIBBEAN AND PREFRONTAL
SHEAR LINE APPROACHES THE FORECAST AREA...WITH WIDESPREAD
CONVECTION LIKELY TO DEVELOP.

JN BAPTISTE...MS (SAINT LUCIA)
NANDA...MDS (SURINAME)
DAVISON...WPC (USA)
$$





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