Prognostic Meteorological Discussion
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FXCA20 KWBC 281819
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
218 PM EDT TUE APR 28 2015

DISCUSSION FROM APRIL 28/12 UTC: A MID/UPPER LEVEL TROUGH OVER THE
SOUTHERN USA AND A RIDGE OVER THE CARIBBEAN DOMINATES THE FLOW
PATTERN ACROSS THE DOMAIN. THE TROUGH EXTENDS ACROSS THE SOUTHERN
USA TO THE NORTHERN STATES OF MEXICO...WITH BROAD CYCLONIC VORTEX
OVER THE SOUTHERN MISSISSIPPI VALLEY EARLY IN THE CYCLE. THIS IS
TO LIFT TO THE EAST-NORTHEAST THROUGH WEDNESDAY EVENING...EXITING
THE MID ATLANTIC REGION IN THE USA EARLY ON THURSDAY MORNING. AT
LOW LEVELS THIS SUSTAINS CYCLOGENESIS OVER THE NORTHERN
GULF...WITH SURFACE FRONT TO SURGE ACROSS TAMAULIPAS-VERACRUZ
EARLY IN THE CYCLE. THE DEEPENING LOW TO THE NORTH WILL SUSTAIN
BOUNDARY LAYER WINDS OF 25-30KT ACROSS THE WESTERN GULF OF MEXICO
THROUGH MIDDAY ON WEDNESDAY...WITH WINDS WEAKENING TO 15-20KT
LATER IN THE DAY AS THE GRADIENT STARTS TO SLACKEN. SURFACE FRONT
IS TO THEN SURGE ACROSS SOUTH FLORIDA TO THE YUCATAN PENINSULA
LATER ON WEDNESDAY...MOVING TO WESTERN CUBA-THE YUCATAN PENINSULA
EARLY ON THURSDAY MORNING. THROUGH THURSDAY AFTERNOON THE FRONT
WILL MOVE ACROSS THE NORTHWEST BAHAMAS-WESTERN CUBA-YUCATAN/GULF
OF HONDURAS...WHERE IT IS TO REMAIN THROUGH MIDDAY ON FRIDAY WHILE
GRADUALLY WEAKENING. FURTHERMORE...AS THE FRONT ENTERS THE YUCATAN
LATER ON WEDNESDAY...IT IS TO SUSTAIN AN INDUCED/PREFRONTAL TROUGH
ACROSS THE WESTERN CARIBBEAN/NORTHERN HONDURAS.

BROAD TROUGH PATTERN TO THE NORTH IS TO INITIALLY FAVOR SCATTERED
CONVECTION ACROSS CENTRAL PORTIONS OF MEXICO/SIERRA MADRE DEL
SUR...WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.
BUT AS THE FRONT SURGES ACROSS THE WESTERN GULF...AND NORTHERLIES
INCREASE...MOST ACTIVE CONVECTION IS EXPECTED FROM SOUTHERN
TAMAULIPAS TO VERACRUZ/SOUTHERN STATES OF MEXICO-THE
YUCATAN/BELIZE...WITH RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA
OF 15-30MM. THROUGH WEDNESDAY EVENING THE FOCUS OF THE CONVECTION
SHIFTS TO GUATEMALA-HONDURAS...WHERE IT IS TO SUSTAIN RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM. ACROSS THE
NORTHWEST-CENTRAL BAHAMAS THIS IS TO THEN FAVOR RAINFALL AMOUNTS
OF 05-10MM/DAY AND MAXIMA OF 15-30MM ON WEDNESDAY TO
THURSDAY...WHILE OVER WESTERN CUBA EXPECTING ACCUMULATION OF
10-15MM/DAY AND MAXIMA OF 20-40MM.

MID/UPPER LEVEL RIDGE TO THE SOUTH IS TO EXTEND EAST-TO-WEST
ACROSS THE TROPICAL ATLANTIC-CARIBBEAN BASIN TO CENTRAL
AMERICA/SOUTHERN STATES OF MEXICO. THE STRONG RIDGE PATTERN
SUSTAINS A CAP INVERSION ACROSS MOST OF THE BASIN...FAVORING DRY
AND STABLE CONDITIONS ACROSS THE GREATER/LESSER ANTILLES INTO THE
EASTERN CARIBBEAN/NORTHERN SOUTH AMERICA. TROUGH OVER THE SOUTHERN
USA IS TO LIFT OVER THIS AXIS AS IT STREAMS TO THE EAST-NORTHEAST.
THE RIDGE...MEANWHILE...IS TO HOLD NEARLY UNCHANGED THROUGH THE
END OF THE WEEK. AT LOW LEVELS...BROAD RIDGE DOMINATES THE CENTRAL
ATLANTIC-EASTERN CARIBBEAN. THIS...IN-TURN...FAVORS A
SOUTH-SOUTHEASTERLY FLOW ACROSS THE EASTERN CARIBBEAN ISLES...AND
A SOUTHEASTERLY FLOW ACROSS THE CENTRAL-NORTHWEST CARIBBEAN. IN A
TIGHT GRADIENT...TRADES ARE SURGING ACROSS THE TROPICAL
ATLANTIC-LESSER ANTILLES...WITH THE METEOSAT RGB DUST PRODUCT
SHOWING A SAHARAN AIR LAYER QUICKLY PROPAGATING ACROSS THE
TROPICAL ATLANTIC INTO THE EASTERN CARIBBEAN. AS THIS ENTERS THE
BASIN...LOW PWAT CONTENT IS TO PLUMMET EVEN MORE. AS A
RESULT...LITTLE TO NO CONVECTION IS EXPECTED ACROSS
JAMAICA-HISPANIOLA-PUERTO RICO...ISLAND CHAIN...THE GUIANAS AND
MOST OF VENEZUELA DURING THE NEXT SEVERAL DAYS.

SOUTHERN CENTRAL AMERICA-COLOMBIA REMAIN ON THE FRINGES OF THIS
RIDGE...WITH HIGHER PWAT CONTENT/DEEPER MOISTURE AVAILABLE TO
SUSTAIN CONVECTION. HOWEVER...THE EASTERN PACIFIC ITCZ IS TO
REMAIN SOUTH OF THE ISTHMUS INTO THE EJE CAFETERO OVER WESTERN
COLOMBIA DURING THE NEXT FEW DAYS. HOWEVER... AN ILL ORGANIZED
CELL OF THE PANAMANIAN LOW OVER THE EASTERN PACIFIC IS TO KEEP
MOST ACTIVE CONVECTION ALONG THE COAST AND OFFSHORE WATERS OF
WESTERN COLOMBIA. IN THIS AREA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM. ON THE ANDEAN REGION-SIERRA
NEVADA DE SANTA MARTA EXPECTING RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-30MM. ON THE EASTERN PLAINS OF COLOMBIA AND
NORTHWEST VENEZUELA EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-30MM. OVER PANAMA-COSTA RICA...DIURNAL CONVECTION IS
TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15MM...WITH
MAXIMA OF 15-20MM/DAY ON WEDNESDAY AND ONWARD.

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

CRAIG...TTMS (TRINIDAD AND TOBAGO)
SAMUEL...MDS (SURINAME)
DAVISON...WPC (USA)
$$




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