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Tropical Discussion
 
(Latest Discussion - Issued 1844Z Oct 23, 2017)
 
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TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
244 PM EDT MON OCT 23 2017

TROPICAL DISCUSSION FROM OCT 23/12 UTC: DEEPENING POLAR TROUGH IS
TO DOMINATE THE FLOW ACROSS WESTERN PORTIONS OF THE DOMAIN...WITH
MID LEVEL TROUGH AXIS TO AMPLIFY ACROSS THE CENTRAL/EASTERN USA TO
THE NORTHERN GULF OF MEXICO LATER ON TUESDAY. AT LOW LEVELS THIS
SUSTAINS A SURFACE FRONT THAT MOVES ACROSS NORTHERN FLORIDA-THE
GULF OF MEXICO TO THE STATE OF VERACRUZ LATER TODAY. ON TUESDAY
MORNING THE FRONT WILL MOVE TO CENTRAL FLORIDA...TRAILING ACROSS
THE YUCATAN TO VERACRUZ. THIS WILL BE ACCOMPANIED BY A NORTHERLY
WIND SURGE OF 20-30KT...AND AN ENSUING TEHUANTEPECER JET OF 50KT.
BUILDING POLAR RIDGE IS TO THEN DISPLACE THE FRONT FARTHER EAST
AND SOUTH...WITH THE FRONT RACING ACROSS FLORIDA TO THE NORTHWEST
BAHAMAS-WESTERN CUBA LATER ON WEDNESDAY. A PREFRONTAL SHEAR LINE
IS TO ACCOMPANY THE SURFACE FRONT AS IT RACES ACROSS THE GULF...TO
MOVE OVER THE YUCATAN-BELIZE/GUATEMALA LATER TODAY...TO THEN
MEANDER OVER THE GULF OF HONDURAS ON TUESDAY-EARLY WEDNESDAY.
LATER IN THE CYCLE IT IS TO MEANDER ACROSS CUBA TO THE CAYMAN
ISLES-NORTHEASTERN HONDURAS. THE FRONT AND STRONG FRONTAL
NORTHERLIES WILL COMBINE WITH ANOMALOUSLY WARM SEA SURFACE
TEMPERATURES ACROSS THE GULF OF MEXICO TO FAVOR HEAVY RAINFALL
AMOUNTS. MOST INTENSE ARE EXPECTED ACROSS SOUTHERN
VERACRUZ-CHIAPAS IN SOUTHERN MEXICO AND CENTRAL GUATEMALA...WITH
ACCUMULATION OF 50-10MM/DAY AND MAXIMA OF 150-250MM EXPECTED
THROUGH TUESDAY MORNING. ON TUESDAY TO WEDNESDAY...AS THE WINDS
INTENSIFY...HEAVY CONVECTION IS TO SPREAD ACROSS CHIAPAS TO
CENTRAL GUATEMALA WHERE IT IS TO FAVOR SIMILAR RAINFALL AMOUNTS.
OVER THE YUCATAN PENINSULA PREFRONTAL CONVECTION IS TO TRIGGER
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM EARLY IN THE
CYCLE. ON TUESDAY THIS INTENSIFIES TO 15-20MM/DAY AND MAXIMA OF
30-60MM. OVER BELIZE-NORTHERN HONDURAS/CENTRAL GUATEMALA THE SHEAR
LINE WILL SUSTAIN RAINFALL AMOUNTS OF 25-50MM/DAY AND MAXIMA OF
75-125MM EARLY ON TUESDAY. ON TUESDAY-WEDNESDAY THIS INCREASES TO
50-100MM/DAY AND MAXIMA OF 150-250MM. OVER THE NORTHWEST BAHAMAS
EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM
WEDNESDAY TO THURSDAY...WHILE ACROSS WESTERN CUBA EXPECTING
RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

AS THE POLAR TROUGH DEEPENS ACROSS THE GULF OF MEXICO IT IS TO
INTERACT WITH A LOW/TROUGH OVER THE SOUTHERN CARIBBEAN. GLOBAL
MODELS AGREE ON THIS LOW LIFTING ALONG THE COAST OF NICARAGUA.
THIS WILL THEN DRAW THE ITCZ NORTH OF ITS CLIMATOLOGICAL POSITION
ACROSS THE CENTRAL CARIBBEAN...WITH PLUME OF DEEP TROPICAL
MOISTURE REACHING JAMAICA ON WEDNESDAY. ACROSS COSTA RICA-SOUTHERN
NICARAGUA EXPECTING ITCZ RELATED CONVERGENCE TO TRIGGER RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM. ON TUESDAY-WEDNESDAY
IT INCREASES TO 20-30MM/DAY AND MAXIMA OF 50-100MM...WHILE ON
WEDNESDAY THE MAXIMA PEAKS AT 75-125MM. OVER EASTERN
NICARAGUA/NORTHEAST HONDURAS EXPECTING RAINFALL AMOUNTS OF
25-50MM/DAY AND MAXIMA OF 75-125MM. LATER IN THE CYCLE...AS DEEP
TROPICAL MOISTURE SURGES ACROSS THE CENTRAL CARIBBEAN...THIS IS TO
FAVOR SCATTERED CONVECTION ACROSS WESTERN JAMAICA WITH RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM. OVER NORTHERN
COLOMBIA/NORTHWEST VENEZUELA EXPECT RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM THROUGH TUESDAY MORNING. THROUGH
WEDNESDAY IT DECREASES TO 05-10MM/DAY AND MAXIMA OF 15-25MM.
HIGHER AMOUNTS ARE EXPECTED ALONG THE WEST COAST OF
COLOMBIA/ANDEAN REGION EARLY IN THE PERIOD...WITH ACCUMULATION OF
15-20MM/DAY AND MAXIMA OF 30-60MM. THROUGH WEDNESDAY...AS THE LOW
LEVEL WINDS BACK TO THE SOUTH-SOUTHEAST...IT DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-25MM.

SOUTH OF THE AMPLIFYING POLAR TROUGH...A BROAD UPPER LEVEL RIDGE
EXTENDS ACROSS CENTRAL AMERICA-WESTERN CARIBBEAN. A TUTT TO THE
EAST EXTENDS SOUTH FROM A CLOSED LOW NORTH OF PUERTO RICO/VIRGIN
ISLES TO THE EASTERN CARIBBEAN/NORTHEAST VENEZUELA. AS THE POLAR
TROUGH TO THE NORTH DEEPENS...IT WILL DISPLACE THE RIDGE TO THE
EAST. THIS...IN-TURN...PUSHES THE TUTT TO EAST ACROSS THE LESSER
ANTILLES LATER ON WEDNESDAY. MEANWHILE...THE TROUGH IS TO INTERACT
WITH THE ITCZ AS IT MEANDERS OVER THE GRENADINES-TRINIDAD/TOBAGO
TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF
20-30MM...WITH SIMILAR AMOUNTS ACROSS NORTHERN GUYANA. OVER
VENEZUELA MOST ACTIVE CONVECTION IS EXPECTED ACROSS AMAZONIA TO
THE SOUTH...WITH ACCUMULATION OF 10-15MM/DAY AND MAXIMA OF 20-30MM
EARLY IN THE CYCLE...INCREASING TO 20-40MM ON TUESDAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:
INITIAL   24    36    48    60    72    84    96   TYPE  SOF
43W      46W   49W   52W   54W   57W   59W   61W   TW    10N
56W      58W   60W   62W   64W   66W   68W   70W   TW    15N
58W      60W   63W   65W   67W   DISSIPATES    TUTT-IND  22N
87W      89W   91W   DISSIPATES                    TW    21N

TROPICAL WAVE ALONG 43W AND SOUTH OF 10N REACHES NORTHERN FRENCH
GUIANA ON TUESDAY TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND
MAXIMA OF 10MM. ACROSS SURINAME-GUYANA THIS IS TO THEN TRIGGER
RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM ON WEDNESDAY.

TROPICAL WAVE ALONG 56W AND SOUTH OF 15N IS TO TRIGGER SCATTERED
CONVECTION ACROSS NORTHERN GUYANA-NORTHEAST
VENEZUELA-GRENADINES/TRINIDAD AND TOBAGO...TO SUSTAIN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM. AS IT PULLS ACROSS
EASTERN VENEZUELA THIS IS TO THEN TRIGGER SIMILAR RAINFALL
AMOUNTS...WHILE OVER THE ABC ISLANDS EXPECTING ACCUMULATION OF
00-05MM/DAY AND MAXIMA OF 10MM.

DEEP TUTT OVER THE EASTERN CARIBBEAN SUSTAIN AN INDUCED TROUGH IN
THE EASTERLY TRADES WITH AXIS NORTH ALONG 58W. THIS MOVES OVER THE
FRENCH ISLANDS EARLY ON TUESDAY TO FAVOR RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM...WHILE ACROSS THE
LEEWARD-VIRGIN ISLANDS EXPECTING ACCUMULATION OF 00-05MM/DAY AND
MAXIMA OF 10MM.

WANING TROPICAL WAVE EXTENDS ALONG 87W TO 21N. THIS IS MERGING
INTO A PREFRONTAL TROUGH OVER THE WESTERN CARIBBEAN/THE
YUCATAN...AND AS A RESULT IT IS EXPECTED TO QUICKLY DISSIPATE.

GUY...NMS (BELIZE)
PECK...MS (JAMAICA)
DAVISON...WPC (USA)