Tropical Weather Discussion
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000
AXNT20 KNHC 170603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI APR 17 2015

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N14W SW
TO 05N15W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 02S30W TO
THE COAST OF NORTHERN BRAZIL NEAR 02S44W. ISOLATED MODERATE
CONVECTION IS FROM 07S TO 03N WEST OF 10W.

...DISCUSSION...

GULF OF MEXICO...

A 1017 MB LOW OVER SOUTH CAROLINA AND GEORGIA ADJACENT WATERS
EXTENDS A COLD FRONT SW ACROSS NORTHERN FLORIDA AND ACROSS THE
NE GULF FROM 28N82W NW TO SOUTHERN ALABAMA NEAR 30N87W. W OF THE
FRONT A SURFACE TROUGH EXTENDS FROM 28N86W TO 27N93W. LOW LEVEL
MOISTURE CONVERGENCE ASSOCIATED WITH THE TROUGH ALONG WITH A
DIFFLUENT ENVIRONMENT ALOFT ACROSS THE N-NE GULF AND THE SW N
ATLC SUPPORTS SCATTERED MODERATE CONVECTION AND TSTMS N OF 27N
BETWEEN 86W AND 92W. SCATTERED SHOWERS ARE OVER THE REMAINDER NE
GULF AND NORTHERN TO CENTRAL FLORIDA. GOES-GEO COLOR IMAGERY AND
SURFACE OBSERVATIONS INDICATE THE PRESENCE OF FOG OVER THE NW
GULF N OF 25N W OF 91W. SURFACE RIDGING OVER THE ATLC CONTINUE
TO PROVIDE SE WIND FLOW OF 5 TO 10 KT MAINLY S OF 28N. SURFACE
RIDGING WILL BE THE DOMINANT FEATURE OVER THE EASTERN BASIN THE
NEXT THREE DAYS WHILE LOW PRESSURE WILL CONTINUE W OF 90W.
SHOWERS ACROSS THE NORTHERN GULF WILL CONTINUE THROUGH FRIDAY
NIGHT.

CARIBBEAN SEA...

A BROAD SURFACE RIDGE OVER THE ATLC OCEAN EXTENDS TO THE
NORTHERN CARIBBEAN WHILE LOWER PRESSURE DOMINATES ELSEWHERE S OF
14N. A SLIGHTLY TIGHTER PRESSURE GRADIENT IS OVER THE CENTRAL
CARIBBEAN ASSOCIATED WITH A 1006 MB LOW OVER N COLOMBIA...THUS
RESULTING IN TRADES OF 20 TO 25 KT S OF 15N BETWEEN 68W AND
78W...BEING THE STRONGEST WINDS ALONG THE COAST OF COLOMBIA.
ELSEWHERE TRADES OF 15 KT DOMINATE. SSMI TPW IMAGERY SHOW
SCATTERED PATCHES OF SHALLOW MOISTURE MOVING ACROSS THE NW AND
EASTERN BASIN...THUS SUPPORTING CLOUDINESS AND POSSIBLE ISOLATED
SHOWERS OVER THE LESSER ANTILLES...CENTRAL AND WESTERN
HISPANIOLA AND THE NW CARIBBEAN N OF 17N. ISOLATED SHOWERS ARE
ON PANAMA COASTAL WATERS. FAIR WEATHER IS ELSEWHERE BEING
SUPPORTED BY DRY AIR SUBSIDENCE FROM ALOFT. NOT SIGNIFICANT
CHANGES ARE EXPECTED DURING THE NEXT TWO DAYS.

...HISPANIOLA...

A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM THE SW N ATLC S
ACROSS THE ISLAND TO NORTHERN VENEZUELA. SHALLOW MOISTURE ALONG
WITH LIFTING PROVIDED BY THE UPPER TROUGH SUPPORT CLOUDINESS
WITH POSSIBLE SCATTERED TO ISOLATED SHOWERS...MAINLY FOCUSED
OVER HAITI AND THE WINDWARD PASSAGE. SHOWERS ARE EXPECTED TO
CONTINUE THROUGH FRIDAY MORNING WHEN A DRY AIRMASS ENTERS THE
ISLAND PROVIDING FAIR WEATHER CONDITIONS FOR THE REMAINDER
WEEKEND.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW OVER THE NORTH-CENTRAL ATLC EXTENDS
A TROUGH TO A BASE N OF 30N...THUS SUPPORTING A SURFACE LOW
PRESSURE SYSTEM FROM WHICH A COLD FRONT EXTENDS SW ENTERING THE
AREA OF DISCUSSION FROM 32N45W TO 27N61W TO 28N70W WHERE IT
TRANSITIONS TO A STATIONARY FRONT NW TO A 1017 MB LOW NEAR
31N78W. A COLD FRONT EXTENDS FROM THIS LOW SW ACROSS NORTHERN
FLORIDA. ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE
COLD FRONT. SCATTERED SHOWERS AND TSTMS ARE OVER THE SW N ATLC N
OF 25N W OF 75W. SURFACE RIDGING AND FAIR WEATHER DOMINATES
ELSEWHERE.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR


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