Prognostic Meteorological Discussion
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FXCA20 KWBC 221849
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
149 PM EST WED NOV 22 2017

TROPICAL DISCUSSION FROM NOV 22/12 UTC: WEST OVER THE DOMAIN...A
LONG WAVE TROUGH EXTENDS FROM THE EASTERN USA TO THE GULF/SOUTHERN
STATES OF MEXICO. A JET ROUNDING THE BASE OF THE TROUGH ON
THURSDAY-FRIDAY IS TO SLOWLY PULL THIS AXIS EAST OVER FLORIDA TO
THE YUCATAN/WESTERN CARIBBEAN LATER ON FRIDAY. ALTHOUGH IT
MEANDERS EAST...THE HIGHLY AMPLIFIED LONG WAVE PATTERN IS TO HOLD
THROUGH THE WEEKEND. AT LOW LEVELS...THE TROUGH ALOFT SUSTAINS A
FRONT ACROSS FLORIDA-A SURFACE LOW OVER THE CENTRAL GULF OF MEXICO
TO TAMAULIPAS. THE LOW IS TO MEANDER EAST ACROSS THE GULF INTO
CENTRAL FLORIDA LATER ON THURSDAY. MEANWHILE...THIS IS TO SUSTAIN
BRISK NORTHERLY WINDS ACROSS THE WESTERN GULF...WITH BOUNDARY
LAYER WINDS OF 35-40KT ALONG THE GULF COAST OF MEXICO LATER TODAY.
THIS IS TO THEN SUSTAIN A TEHUANTEPECER JET OF 40-45KT ON THURSDAY
TO FRIDAY. AS THE WINDS INTENSIFY...THE FRONT SURGES ACROSS
VERACRUZ MEXICO LATER TODAY...AND ON THURSDAY MORNING IT REACHES
THE SOUTHERN STATE OF CHIAPAS. ON THURSDAY TO FRIDAY THIS BOUNDARY
MOVES OVER THE YUCATAN...NEARING THE NORTHWEST BAHAMAS-WESTERN
CUBA EARLY ON SATURDAY MORNING. THE STRONG NORTHERLIES OVER
SOUTHERN MEXICO ARE TO FAVOR SCATTERED CONVECTION ACROSS NORTHERN
CHIAPAS-SOUTHERN VERACRUZ...WITH ACCUMULATION OF 10-15MM/DAY AND
MAXIMA OF 20-30MM. ON THURSDAY-FRIDAY THIS DECREASES TO
05-10MM/DAY AND MAXIMA OF 15-20MM... WHILE ON FRIDAY EXPECTING
ADDITIONAL RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF 10MM.
OVER CAMPECHE/YUCATAN EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM TODAY THROUGH THURSDAY. AS IT ENTERS THE
NORTHWEST BAHAMAS-CUBA ON SATURDAY MORNING EXPECTING RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM.

A MID/UPPER LEVEL RIDGE TO THE EAST...MEANWHILE...EXTENDS FROM
NORTHERN VENEZUELA/ EASTERN CARIBBEAN TO THE WESTERN ATLANTIC. AT
500 HPA THE RIDGE IS TO CENTER ON A CLOSED HIGH OVER PUERTO RICO
LATER THIS AFTERNOON...TO THEN MEANDER NORTH-NORTHEAST OF THE
ISLAND ON THURSDAY-FRIDAY. AS IT MEANDERS OVER THE EASTERN
CARIBBEAN ISLES THE MID LEVEL RIDGE SUSTAINS A STRONG SUBSIDENCE
CAP THAT IS INHIBITING ORGANIZED DEEP CONVECTION. AT LOW
LEVELS...BROAD RIDGE DOMINATES THE FLOW ACROSS THE WESTERN
ATLANTIC TO THE NORTHERN CARIBBEAN. THIS FAVORS A BRISK EASTERLY
FLOW ACROSS THE ISLAND CHAIN TO THE CENTRAL CARIBBEAN...WITH 850
HPA WINDS PEAKING AT 15-20KT. POLAR FRONTS EXITING THE EASTERN USA
ARE TO PRESS AGAINST THIS RIDGE...WITH AXIS TO WEAKEN WHILE
RELOCATING TO THE CENTRAL ATLANTIC EARLY IN THE CYCLE. EASTERLY
TRADES ARE TO PERSIST ACROSS THE BASIN...WITH WINDS PEAKING AT
10-15KT. EXCEPT FOR TRINIDAD/TOBAGO AND THE GRENADINES...EXPECTING
FAIR WEATHER CONDITIONS TO GENERALLY PREVAIL ACROSS THE ISLAND
CHAIN-PUERTO RICO-HISPANIOLA. OVER TRINIDAD AND TOBAGO ITCZ
RELATED CONVERGENCE ON THURSDAY-FRIDAY IS TO RESULT IN RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.

ALSO AT LOW LEVELS...AN INVERTED TROUGH OVER THE CARIBBEAN EXTENDS
NORTH ALONG 80W BETWEEN COSTA RICA/WESTERN PANAMA TO EASTERN CUBA.
FRONTAL LOW OVER THE GULF OF MEXICO PHASES WITH THIS PERTURBATION
ON THURSDAY...WITH AXIS BECOMING SOMEWHAT BETTER ORGANIZED WHILE
MERGING WITH AN INDUCED/PREFRONTAL TROUGH. THIS IS TO ALSO SUSTAIN
GRADUAL INTENSIFICATION OF THE PANAMANIAN LOW TO THE SOUTH OF THE
ISTHMUS. THE LOW IS TO SUSTAIN A WESTERLY FLOW ACROSS THE EASTERN
PACIFIC TO THE EJE CAFETERO IN WESTERN COLOMBIA...WHERE IT IS TO
ENHANCE COASTAL CONVERGENCE. OVER THE  BAHAMAS-TURKS THIS IS TO
FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM. ON
THURSDAY IT DECREASES TO 00-05MM/DAY AND MAXIMA OF 10MM ACROSS THE
CAYMAN ISLES EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15MM. THROUGH FRIDAY IT INCREASES TO 10-15MM/DAY AND MAXIMA OF
20-30MM. ACROSS JAMAICA EXPECTING RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-40MM. ON THURSDAY THE MAXIMA DECREASES TO
20-30MM. OVER PANAMA-COSTA RICA THIS IS TO INTERACT WITH THE ITCZ
IN SUPPORT OF SCATTERED CONVECTION...WITH ACCUMULATION OF
10-15MM/DAY AND MAXIMA OF 20-30MM. THROUGH FRIDAY THIS IS FORECAST
TO INCREASES TO 15-20MM/DAY AND MAXIMA OF 25-50MM. OTHER
CONVECTION OVER THE CENTRAL CARIBBEAN IS TO AFFECT ISLA DE
PROVIDENCIA AND SAN ANDRES WITH RAINFALL AMOUNTS OF 10-15MM/DAY
AND MAXIMA OF 20-30MM.

UNDER INFLUENCE OF THE PANAMANIAN LOW...AND LONG FETCH WESTERLY
FLOW...HIGHER AMOUNTS ARE EXPECTED OVER WESTERN COLOMBIA. IN THIS
AREA EXPECTING RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF
30-60MM DURING THE NEXT FEW DAYS. OTHER CONVECTION IS EXPECTED
BETWEEN AMAZONIA IN SOUTHERN VENEZUELA AND THE PIEDEMONTE LLANERO
OVER EASTERN COLOMBIA. IN THIS AREA EXPECT RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-35MM. THIS DECREASES TO 05-10MM/DAY
AND MAXIMA OF 15-20MM ON THURSDAY-FRIDAY.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC:
INITIAL   24    36    48    60    72    84    96    TYPE
SOF
50W      52W   55W   58W   60W   64W   67W   70W    EW
15N
55W      57W   59W   61W   63W   66W   69W   71W    TUTT-INDCD
26N
65W      67W   69W   71W   73W   76W   79W   81W    EW
16N

AN EASTERLY WAVE ALONG 50W AND SOUTH OF 15N SUSTAINS SCATTERED
CONVECTION ALONG THE ITCZ TO THE NORTH. OVER FRENCH GUIANA TO
SURINAME THIS IS TO ONLY TRIGGER LIGHT CONVECTION WITH
ACCUMULATION OF 00-05MM/DAY. EARLY ON FRIDAY IT MOVES ACROSS
NORTHERN GUYANA TO NORTHEAST VENEZUELA-TRINIDAD/TOBAGO-SOUTHERN
WINDWARD ISLES. IN THIS AREA IT IS TO SUSTAIN RAINFALL AMOUNTS OF
05-10MM/DAY AND MAXIMA OF 15-20MM. THEREAFTER MOST ACTIVE IS
EXPECTED ACROSS SOUTHERN-CENTRAL VENEZUELA TO EASTERN
COLOMBIA...WHERE IT IS TO SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-25MM.

A TUTT INDUCED PERTURBATION IN THE EASTERLY TRADES EXTENDS ALONG
55W AND NORTH OF 17N. THIS REACHES THE NORTHEAST CARIBBEAN LATER
ON THURSDAY...CROSSING THE VIRGIN ISLES TO EASTERN PUERTO RICO ON
FRIDAY. A PLUME OF SHALLOW MOISTURE ACCOMPANIES THIS WAVE. AS IT
ENTERS THE EASTERN CARIBBEAN...THE MEANDERING MID LEVEL RIDGE AND
ASSOCIATED TRADE WINDS ARE TO CAP MOISTURE TO ATMOSPHERE BELLOW
700-600 HPA. ACROSS THE NORTHERN LEEWARD/VIRGIN ISLES TO PUERTO
RICO THIS IS TO FAVOR RAINFALL AMOUNTS OF 00-05MM/DAY AND ISOLATED
MAXIMA OF 10MM ON THURSDAY-FRIDAY. SIMILAR AMOUNTS ARE EXPECTED
ACROSS THE DOMINICAN REPUBLIC ON FRIDAY TO SATURDAY.

AN EASTERLY WAVE ALONG 65W AND SOUTH OF 16N IS TO ENHANCE
CONVECTION ACROSS SOUTHERN VENEZUELA OVER THE NEXT DAY OR SO...TO
FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-35MM. ON
THURSDAY...ACROSS EASTERN COLOMBIA/WESTERN VENEZUELA...THIS IS TO
THEN FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM.
ACROSS WESTERN COLOMBIA THIS INCREASES TO 15-20MM/DAY AND MAXIMA
OF 30-60MM LATER ON THURSDAY/FRIDAY MORNING.

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

$$




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