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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1920Z Nov 13, 2014)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
220 PM EST THU NOV 13 2014

DISCUSSION FROM NOVEMBER 13/00UTC: AT MID/UPPER LEVELS...A RIDGE
EXTENDS FROM CENTRAL AMERICA ACROSS THE WESTERN-CENTRAL CARIBBEAN
TO THE GREATER ANTILLES/SOUTHEAST ATLANTIC. A 250 HPA HIGH TO THE
SOUTH OF THE CAYMAN ISLES ANCHORS THIS RIDGE. POLAR TROUGH OVER
NORTH AMERICA CONTINUES TO PRESS AGAINST THIS AXIS. THE TROUGH
MOVES TO THE EASTERN USA LATER ON THURSDAY... AND TROUGH FRIDAY
EVENING IT MOVES INTO THE WESTERN ATLANTIC. AS THE TROUGH LIFTS
OVER THE RIDGE TO THE SOUTH...THE RIDGE IS FORECAST TO WEAKEN OVER
THE GULF WHILE MAINTAINING ITS FOOTHOLD OVER THE WESTERN
CARIBBEAN-GREATER ANTILLES. PERSISTENT MID/UPPER LEVEL RIDGE
PATTERN IS TO GENERALLY FAVOR A SUBSIDENCE CAP INVERSION ACROSS
SOUTHERN MEXICO-NORTHERN CENTRAL AMERICA AND THE GREATER ANTILLES.

AT LOW LEVELS...THE TROUGH ALOFT SUSTAINS A POLAR FRONT ACROSS THE
GULF TO VERACRUZ IN CENTRAL MEXICO. POLAR RIDGE IS TO THEN MOVE
ACROSS THE SOUTHERN USA TO THE WESTERN ATLANTIC LATER ON SATURDAY.
THIS IS TO DRIVE THE FRONT SOUTH ACROSS THE FLORIDA PENINSULA-GULF
OF MEXICO TO SOUTHERN VERACRUZ EARLY ON FRIDAY MORNING. BOUNDARY
THEN MOVES TO THE NORTHWEST BAHAMAS/SOUTH FLORIDA LATER ON FRIDAY
WHERE IT IS EXPECTED TO STALL WHILE GRADUALLY WEAKENING. TRAILING
END OVER THE GULF...MEANWHILE...IS TO RETROGRESS ALONG THE COAST
OF MEXICO TO THE SOUTHERN USA. EARLY IN THE CYCLE THE POLAR 
INCURSION IS TO SUSTAIN A TEHUANTEPECER JET OF 45-50KT. THROUGH
FRIDAY EVENING THIS IS TO GRADUALLY WEAKEN AS THE GRADIENT BEGINS
TO SLACKEN. ALTHOUGH THE NORTHERLIES WEAKEN ACROSS THE
GULF...ACROSS CUBA-WESTERN CARIBBEAN/NORTHERN HONDURAS THEY ARE TO
GRADUALLY SURGE THROUGH FRIDAY EVENING...WITH BOUNDARY LAYER WINDS
EXPECTED TO PEAK AT 20-25KT. AS THE NORTHERLIES SURGE ACROSS
VERACRUZ/ISTHMUS OF TEHUANTEPEC THIS IS TO TAKE ADVANTAGE OF WARM
SEA SURFACE TEMPERATURES TO SUSTAIN MODERATE TO HEAVY RAINFALL
AMOUNTS...WITH ACCUMULATION OF 15-30MM/DAY AND MAXIMA OF 40-80MM.
STRONG TOPOGRAPHICAL FORCING IS LIKELY TO RESULT IN LOCALIZED
EXCESSIVE RAINFALL AMOUNTS. OVER THE NORTHWEST BAHAMAS EXPECT
RAINFALL AMOUNTS OF 00-05MM/DAY IN ISOLATED CONVECTION. OVER
NORTHERN HONDURAS/ISLAS DE LA BAHIA... TOPOGRAPHICALLY ENHANCED
CONVECTION IS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15MM. HIGHER AMOUNTS ARE POSSIBLE ACROSS NORTHEAST
HONDURAS LATER ON FRIDAY...WHERE WE EXPECT MAXIMA OF 20-40MM.

A PREFRONTAL SHEAR LINE IS TO THEN DEVELOP ACROSS THE SOUTHEAST
BAHAMAS-EASTERN CUBA-JAMAICA TO COSTA RICA LATER ON FRIDAY...TO
MOVE EAST INTO NORTHERN HISPANIOLA LATER ON SATURDAY WHILE
TRAILING ACROSS THE CENTRAL CARIBBEAN TO NORTHEAST HONDURAS. THIS
IS TO ENHANCE MOISTURE CONVERGENCE ACROSS NORTHERN HISPANIOLA-THE
TURKS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15MM. HIGHER AMOUNTS ARE EXPECTED OVER JAMAICA ON FRIDAY WITH
MAXIMA OF 20-40MM...SIMILARLY ACROSS COSTA RICA-EASTERN NICARAGUA.

EAST OF THE MID/UPPER LEVEL RIDGE...A TROUGH EXTENDS ACROSS THE
NORTHEAST CARIBBEAN ISLES TO LAKE MARACAIBO. THE TROUGH MOVES OVER
THE LEEWARD ISLES-NORTHERN VENEZUELA/ABC ISLES LATER TODAY/EARLY
FRIDAY MORNING...WHERE IT IS TO REMAIN THROUGH FRIDAY EVENING.
LATER ON SATURDAY IT IS TO BECOME NARROW AND ELONGATED WHILE
STRETCHING TO THE SOUTHWEST ACROSS THE CENTRAL ATLANTIC TO THE
FRENCH ISLES/EASTERN CARIBBEAN. RIDGE TO THE WEST IS TO GENERALLY
FAVOR A STRONG CAP INVERSION ACROSS HISPANIOLA TO PUERTO
RICO/VIRGIN ISLES. BEST INSTABILITY IS EXPECTED TO THE SOUTH
ACROSS THE SOUTHERN WINDWARD ISLES-NORTHEAST VENEZUELA. AT LOW
LEVELS...A BROAD RIDGE DOMINATES FLOW ACROSS THE CENTRAL ATLANTIC
TO THE EASTERN CARIBBEAN...FAVORING AN EASTERLY FLOW ACROSS THE
LESSER ANTILLES. AS THE AFOREMENTIONED POLAR HIGH MIGRATES ACROSS
THE USA MOVES THE WESTERN ATLANTIC LATER ON SATURDAY THIS IS TO
TIGHTEN THE GRADIENT ACROSS THE BASIN FAVORING A 20-25KT WIND
SURGE ACROSS THE TROPICAL ATLANTIC TO THE EASTERN-CENTRAL
CARIBBEAN. EMBEDDED IN THIS FLOW...AN INDUCED/INVERTED TROUGH
EXTENDS NORTH ACROSS THE VIRGIN ISLES. THIS TROUGH IS TO GRADUALLY
WEAKEN/FILL AS IT DRIFTS WEST ACROSS PUERTO RICO TO HISPANIOLA
DURING THE DAY ON THURSDAY. THIS WILL FAVOR A SLIGHT INCREASE IN
PWAT AMOUNTS ACROSS THE EASTERN CARIBBEAN ISLES LATER TODAY...WITH
PWAT TO PEAK AT 25-30MM OVER THE NEXT FEW DAYS. EVOLVING FLOW AND
SURGING EASTERLY TRADES ARE TO FAVOR GENERATION OF TRADE WIND
SHOWERS/STREAMERS ACROSS THE LESSER ANTILLES...WITH RAINFALL
AMOUNTS OF 00-05MM/DAY. MOST ACTIVE CONVECTION IS EXPECTED TO THE
SOUTH OVER THE WINDWARD ISLES-ORINOCO DELTA...WHERE TROUGH ALOFT
IN INTERACTION WITH THE ITCZ IS TO SUSTAIN ORGANIZED CONVECTION.
IN THIS AREA EXPECT RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
30-60MM THROUGH FRIDAY MORNING. THROUGH SATURADY THIS DECREASES TO
10-15MM/DAY AND MAXIMA OF 20-35MM.

SOUTH OVER THE CARIBBEAN...SHEAR LINE CONFLUENCE COMBINES WITH
PANAMANIAN LOW IN SUPPORT OF SCATTERED SHOWERS ACROSS THE ISTHMUS
OF PANAMA AND COSTA RICA. EVOLVING RIDGE PATTERN TO THE NORTH
LEADS TO GRADUAL DISSIPATION OF THE SHEAR LINE CONFLUENCE WHILE
THE PANAMANIAN LOW RETURNS TO ITS CLIMATOLOGICAL POSITION OVER THE
EASTERN PACIFIC. MEANWHILE...THIS IS TO CONTINUE FAVORING
SCATTERED CONVECTION WITH ACCUMULATION OF 15-20MM/DAY AND MAXIMA
OF 30-60MM. THROUGH THURSDAY EVENING THIS BUILDS WEST INTO EASTERN
NICARAGUA...DECREASING TO 20-40MM DURING THE DAY ON FRIDAY. OTHER
CONVECTION IS EXPECTED ON THE ANDEAN REGION OF COLOMBIA AND THE
WESTERN PLAINS...WHERE DIURNAL CONVECTION IS TO SUSTAIN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM THROUGH FRIDAY
MORNING.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
53W     54W    57W    59W    61W    63W     65W   67W     TW

TROPICAL WAVE ALONG 53W IS TO INITIALLY FAVOR SCATTERED CONVECTION
ALONG THE ITCZ. THIS REACHES THE WINDWARD ISLES/NORTHEAST
VENEZUELA EARLY ON SATURDAY MORNING...WHERE IT IS TO SUSTAIN
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. AS IT PULLS
ACROSS THE EASTERN CARIBBEAN UPPER ENVIRONMENTAL CONDITIONS ARE TO
BECOME SOMEWHAT MORE HOSTILE TO CONVECTION...WITH MID/UPPER LEVEL
RIDGE SUSTAINING A SUBSIDENCE PATTERN. AS A RESULT...AS IT PULLS
ACROSS VENEZUELA...IT IS TO ONLY FAVOR RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15MM.

JN BAPTISTE...MS (SAINT LUCIA)
MEDINA...ONAMET (REPUBLICA DOMINICANA)
DAVISON...WPC (USA)