Prognostic Meteorological Discussion
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FXCA20 KWBC 241943
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 PM EST FRI FEB 24 2017

TROPICAL DISCUSSION FROM FEB 24/12 UTC: SURFACE COLD FRONT IN THE
NORTHERN CARIBBEAN IS STARTING TO PULL NORTHEASTWARD WHILE
WEAKENING. BY FRIDAY EVENING THE FRONT WILL EXTEND AN ILL DEFINED
BOUNDARY INTO THE SOUTHEASTERN BAHAMAS TO THEN EXIT THE REGION.
DEEP CONVECTION WITH THIS SYSTEM IS LIMITING TO OPEN WATERS OF THE
NORTHERN ATLANTIC. ALTHOUGH THE FRONT AND UPPER TROUGH ARE EXITING
THE BASIN...THEY HAVE TEMPORARILY INTERRUPTED THE SEASONAL STRONG
EASTERLY TRADE REGIME IN THE WESTERN CARIBBEAN. THIS IS LEADING TO
WESTERLIES ALONG THE PACIFIC COAST OF EL
SALVADOR/GUATEMALA/NICARAGUA AND HONDURAS...WHICH ARE TO CONTINUE
SUSTAINING ENHANCED SHOWERS IN THESE REGIONS. AS A LOW-LEVEL
TROUGH ORGANIZES IN THE GULF OF HONDURAS ON SATURDAY AND EASTERLY
TRADES START ORGANIZING IN THE CARIBBEAN BASIN DURING THIS
PERIOD...EXPECTING A PEAK IN LOW-LEVEL MOISTURE CONVERGENCE AND
INSTABILITY DEVELOPING ON SATURDAY. ON FRIDAY...WESTERLY WINDS
WILL BE ABLE TO TRIGGER A FEW SHOWERS AND A STRAY/ISOLATED
THUNDERSTORM LATE IN THE EVENING. EXPECTING MAXIMA UNDER 10MM IN
SHOWERS. STRONG INSTABILITY IN ANY THUNDERSTORM THAT DEVELOPS HAS
THE POTENTIAL OF PRODUCING HEAVY DOWNPOURS AND ISOLATED MAXIMA OF
15-20MM/DAY. BY SATURDAY...EXPECTING AN INCREASE IN THE COVERAGE
OF CONVECTION WHERE NUMEROUS SHOWERS AND A FEW ISOLATED
THUNDERSTORMS ARE TO PRODUCE 10-15MM/DAY AND ISOLATED MAXIMA OF
20-35MM. AMOUNTS ARE TO START DECREASING AFTER...AS THE EASTERLY
TRADES RETURN AND ADVECT THE MOIST AND UNSTABLE AIR MASS WESTWARD
INTO THE PACIFIC. ONCE EASTERLY TRADES RETURN...A MORE SEASONAL
PATTERN OF ENHANCED SHOWERS IN THE CARIBBEAN BASINS OF COSTA RICA
AND NICARAGUA WILL ESTABLISH.

THE NEXT FRONT TO ARRIVE IN THE BASIN WILL EXIT THE COAST OF TEXAS
ON FRIDAY EVENING. BY SATURDAY MORNING IT WILL EXTEND ACROSS
SOUTHERN ALABAMA INTO NORTHERN TAMAULIPAS IN MEXICO. BY SATURDAY
EVENING WILL EXTEND FROM THE FLORIDA PANHANDLE INTO SOUTHERN
TAMAULIPAS. AFTER THIS PERIOD...THE WESTERN TIER OF THE FRONT WILL
START RETROGRESSING NORTHWARD ACROSS THE GULF COAST OF MEXICO
WHILE THE GRADIENT BECOMES ILL-DEFINED. THIS FRONT WILL HAVE
LIMITED EFFECTS ON THE PRECIPITATION IN THE BASIN...YET EASTERLIES
AHEAD OF THE SYSTEM WILL ENHANCE LOW-LEVEL MOISTURE CONVERGENCE
ALONG THE COAST OF NORTHEASTERN MEXICO...WHERE EXPECTING
05-10MM/DAY AND MAXIMA OF 10MM BY SUNDAY-MONDAY.

ACROSS THE CARIBBEAN BASIN...PERSISTENT MID-UPPER TROUGH PATTERN
ACROSS THE EASTERN CARIBBEAN WILL GRADUALLY DESTABILIZE THE
ATMOSPHERE. THIS WILL LEAD TO A GRADUAL INCREASE IN THE COVERAGE
AND INTENSITY OF LIGHT RAIN SHOWERS THROUGH EARLY NEXT WEEK.
YET...EXPECTING ACCUMULATIONS TO STAY GENERALLY UNDER 10MM/DAY. A
TROUGH IN THE TRADES WILL ARRIVE INTO THE LESSER ANTILLES ON
SUNDAY...AIDED BY A TRAILING TRADE WIND SURGE. THIS WILL LEAD TO
AN ENHANCEMENT IN THE COVERAGE AND DEPTH OF LIGHT RAIN SHOWERS.
INSTABILITY WILL BE SUFFICIENT TO PRODUCE VERY ISOLATED AND
SHORT-LIVED THUNDERSTORMS...WHICH HAVE THE POTENTIAL TO PRODUCING
ISOLATED MAXIMA OF 15MM/DAY ESPECIALLY IN THE NORTHERN LESSER
ANTILLES AND VIRGIN ISLANDS.

IN NORTHERN SOUTH AMERICA AND THE SOUTHERN CARIBBEAN...EXPECTING
AN INCREASE IN ACCUMULATIONS IN ASSOCIATION WITH A TROUGH
PROPAGATING IN THE TRADES. THIS TROUGH HAS BEEN UNDULATED BY
AFOREMENTIONED UPPER TROUGH THAT IS EXITING THE EASTERN CARIBBEAN
INTO THE TROPICAL ATLANTIC. AS THE UPPER FORCING DECREASES...THE
REGION OF UNSETTLED WEATHER CURRENTLY IN THE GUIANAS WILL
PROPAGATE WESTWARD TO ENHANCE ACTIVITY IN THE NORTHERN COAST OF
VENEZUELA ON SATURDAY...AND ON COLOMBIA ON SUNDAY. ON
FRIDAY...ENHANCED CONVECTION IN THE GUIANAS AND EXTREME
NORTHEASTERN VENEZUELA WILL LEAD TO AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM. TRACE AMOUNTS ARE EXPECTED IN TRINIDAD AND
TOBAGO AND THE CARIBBEAN COAST OF NORTHEASTERN VENEZUELA. BY
SATURDAY-SUNDAY EXPECTING SCATTERED ACCUMULATIONS OF 05-10MM/DAY
AND ISOLATED MAXIMA NEAR 10MM ALONG THE NORTHERN COAST OF
VENEZUELA. LARGER AMOUNTS ARE EXPECTED  IN THE ANDEAN
REGION...WHERE...UNDER OROGRAPHIC FORCING EXPECTING MAXIMA OF
15-30MM/DAY. AMOUNTS ARE TO PEAK IN COLOMBIA ON
SUNDAY-MONDAY...ESPECIALLY IN THE ANDEAN REGION...WHERE EXPECTING
10-15MM/DAY AND MAXIMA OF 20-35MM.

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

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

$$





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