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Tropical Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1748Z Oct 24, 2014)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
148 PM EDT FRI OCT 24 2014


DISCUSSION FROM OCTOBER 24/00UTC: LARGE UPPER TROUGH IS EXITING
THE EASTERN COAST OF THE UNITED STATES WHILE PRESSING INTO A RIDGE
TO THE SOUTH THAT CENTERS OVER THE HAITIAN PENINSULA. THIS IS
LEADING TO A BROAD AREA WITH VENTILATION THAT IS INTERACTING WITH
A SURFACE FRONT ACROSS THE BAHAMAS-CUBA AND THE NORTHERN GULF OF
HONDURAS/YUCATAN. A SHORT WAVE UPPER TROUGH TRAILS BEHIND MAIN
TROUGH. IT EXTENDS FROM THE SOUTHWESTERN FLORIDA PENINSULA INTO
SOUTHERN YUCATAN/NORTHERN GUATEMALA. THIS TROUGH IS INTERACTING
WITH A SURFACE LOW MOVING NORTHEASTWARD ACROSS THE FLORIDA
STRAIGHT ALONG THE BAROCLINIC BOUNDARY. A SECOND TROUGH DIGGING
FROM THE CENTRAL PLAINS OF THE USA WILL TAKE OVER AND INTERACT
WITH THE SYSTEM...FOCUSING THE BOUNDARY OF LOW-LEVEL CONVERGENCE
AND CONVECTIVE INSTABILITY INTO THE CAYMAN ISLANDS/SOUTHEASTERN
CUBA AND SOUTHEASTERN BAHAMAS TOWARDS SUNDAY AND MONDAY...WITH
SOME MODERATE CONVECTION AFFECTING NORTHERN HISPANIOLA AND JAMAICA
AS WELL. TO THE WEST...NORTHERLY SURGE IS ARRIVING INTO THE GULF
OF HONDURAS WHERE CONVECTIVE INSTABILITY REMAINS VERY HIGH. THESE
WINDS...IN INTERACTION WITH OROGRAPHY AND LARGE MOISTURE
CONTENT...WILL LEAD TO HEAVY RAINFALL AMOUNTS THAT WILL GRADUALLY
DISPLACE EASTWARD AS THE CYCLE PROGRESSES. ANOTHER AREA WITH
WANING HEAVY CONVECTION IS SOUTHERN MEXICO/GUATEMALA...UNDER THE
INFLUENCE OF STRONG OROGRAPHIC UPLIFT AHEAD OF NORTHERLY SURGE.
THROUGH EARLY SATURDAY...LARGEST AMOUNTS ARE EXPECTED OVER THE
BAHAMAS WITH AMOUNTS OF 50-75MM/DAY AND MAXIMA OF 150-200MM.
ACROSS CUBA EXPECTING 20-40MM/DAY AND MAXIMA OF 75-125MM. ACROSS
NORTHERN HONDURAS/BELIZE/EASTERN GUATEMALA EXPECTING SIMILAR
AMOUNTS. ACROSS SOUTHERN GUATEMALA INTO CHIAPAS AND
TABASCO/SOUTHERN VERACRUZ IN MEXICO...EXPECTING 15-20MM/DAY AND
MAXIMA OF 25-50MM. SIMILAR AMOUNTS ARE EXPECTED ACROSS THE CAYMAN
ISLANDS. BY SATURDAY INTO EARLY SUNDAY...LARGEST AMOUNTS ARE
EXPECTED ACROSS NORTHERN HONDURAS WITH 25-50MM/DAY AND MAXIMA OF
75-125MM. ACROSS THE CAYMAN ISLANDS INTO SOUTHEASTERN CUBA AND THE
CENTRAL/SOUTHEASTERN BAHAMAS EXPECTING 15-20MM/DAY AND MAXIMA OF
25-50MM. BY SUNDAY INTO MONDAY...EXPECTING SIMILAR AMOUNTS OVER
THE CAYMAN ISLANDS. ACROSS CUBA AND THE SOUTHEASTERN BAHAMAS/TURKS
AND CAICOS...EXPECTING 10-15MM/DAY AND MAXIMA OF 20-40MM. SIMILAR
AMOUNTS ARE EXPECTED ACROSS PORTIONS OF NORTHEASTERN HISPANIOLA AS
A SHEAR LINE STARTS TO ESTABLISH.

OTHER REGION OF INTEREST WILL BE THE LESSER ANTILLES INTO
NORTHEASTERN SOUTH AMERICA. ALTHOUGH A TROPICAL WAVE IS EXITING
THE REGION...THE WINDWARD ISLANDS AND NORTHEASTERN SOUTH AMERICA
CONTINUE UNDER THE DIVERGENT SIDE OF A TUTT THAT EXTENDS ACROSS
THE CENTRAL LESSER ANTILLES INTO THE LAKE MARACAIBO REGION. THIS
IS INTERACTING WITH ITCZ CONVECTION AND WILL SUSTAIN AN ACTIVE
PATTERN OF SCATTERED THUNDERSTORMS THROUGH THE WEEKEND. THE TUTT
IS FORECAST TO DETACH FROM THE WESTERLIES AND BECOME A CLOSED LOW
AS THE WEEKEND PROGRESSES...TO START SLOWLY RETROGRESSING INTO
EARLY NEXT WEEK. AS THE TUTT RETROGRESSES...ITS DIVERGENT TIER
WILL MEANDER NORTHWESTWARD ONCE AGAIN INTO THE LESSER ANTILLES TO
BRING ANOTHER ROUND OF MODERATE TO HEAVY RAINS IN INTERACTION WITH
THE ITCZ AND NEW TROPICAL WAVE. IT APPEARS THAT RAINY PATTERN WILL
CONTINUE EXPANDING NORTHWESTWARD INTO EARLY NEXT WEEK TO AFFECT
THE LEEWARD ISLANDS ON MONDAY INTO TUESDAY AND THEN PUERTO RICO
AND THE VI. THROUGH EARLY SUNDAY...EXPECTING MAXIMA OF 15-25MM/DAY
ACROSS THE WINDWARD ISLANDS/NORTHEASTERN VENEZUELA AND NORTHERN
GUYANA. DURING SUNDAY INTO MONDAY...AMOUNTS ARE TO INCREASE TO
15-20MM/DAY AND MAXIMA OF 30-60MM...EXPANDING NORTH INTO THE
CENTRAL LESSER ANTILLES.

ACROSS COLOMBIA AND SOUTHERN CENTRAL AMERICA...SEASONAL ACTIVE
PATTERN CONTINUES. MODELS CONTINUE SHOWING AN INCREASE OF THE
WESTERLIES ACROSS THE GULF OF PANAMA WHICH...IN COMBINATION WITH
ARRIVING TROPICAL WAVE...ARE LIKELY TO PRODUCE AN INCREASE IN
ACTIVITY INTO THE WEEKEND. THROUGH EARLY SATURDAY...LARGEST
AMOUNTS ARE EXPECTED ACROSS SOUTHWESTERN COLOMBIA WITH MAXIMA OF
20-45MM/DAY. BY SATURDAY INTO EARLY SUNDAY...EXPECTING AN INCREASE
TO MAXIMA OF 30-60MM/DAY ACROSS WESTERN COLOMBIA...AND 20-40MM/DAY
ACROSS NORTHERN COLOMBIA INTO THE LAKE MARACAIBO REGION. BY SUNDAY
INTO MONDAY...LARGEST AMOUNTS ARE EXPECTED ACROSS NORTHWESTERN
COLOMBIA WITH MAXIMA OF 40-80MM/DAY...AND MAXIMA OF 30-60MM/DAY
ACROSS NORTHERN COLOMBIA/NORTHWESTERN VENEZUELA.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL  24     36     48     60     72     84     96     TYPE
46W     48W    51W    53W    56W    59W    60W    62W     TW
67W     70W    72W    74W    76W    77W    79W    81W     TW

TROPICAL WAVE ALONG 46W WILL APPROACH FRENCH GUIANA DURING
SATURDAY. STRONGEST CONVECTION WILL HOWEVER REMAIN OFFSHORE AS
TUTT IN THE LESSER ANTILLES WILL DRAW THE ITCZ NORTHWARD. THIS
WILL BRING MOST ACTIVITY INTO THE LESSER ANTILLES AND NORTHEASTERN
SOUTH AMERICA ON MONDAY...PRODUCING LOCALLY HEAVY RAINFALL AND
MAXIMA OF 30-60MM/DAY.

TROPICAL WAVE ALONG 67W IS INTERACTING WITH CONVERGENT SIDE OF
TUTT ACROSS THE EASTERN CARIBBEAN...THUS CONVECTION IS BECOMING
LIMITED. THE WAVE WILL HOWEVER IMPACT CONVECTION ACROSS NORTHERN
VENEZUELA AND COLOMBIA...WHERE IT IS TO PRODUCE MAXIMA OF
30-60MM/DAY....AND 40-80MM/DAY ACROSS WESTERN COLOMBIA.

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