Tropical Weather Discussion
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000
AXNT20 KNHC 190005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI APR 18 2014

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURE...
A GALE WARNING REMAINS IN EFFECT FOR THE NE GULF IN ASSOCIATION
WITH A DEEPENING AREA OF LOW PRES LOCATED NEAR 29N85W AT 2100
UTC. THE LOW WILL SHIFT SLOWLY NE...MOVING INLAND ACROSS THE
CENTRAL FLORIDA PANHANDLE TONIGHT...THEN WILL CONTINUE NE TO
EXIT THE GEORGIA COAST SAT AFTERNOON. GALE WINDS AT THE GULF ARE
EXPECTED SUBSIDE LATER TONIGHT. PLEASE SEE THE HIGH SEAS
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 14N16W AND CONTINUES ALONG 09N19W TO 04N21W. THE ITCZ
BEGINS NEAR 04N21W AND CONTINUES ALONG 01N30W 01S40W TO THE
NORTHERN COAST OF BRAZIL NEAR 01S45W. CLUSTERS OF MODERATE TO
ISOLATED STRONG CONVECTION ARE N OF 02N BETWEEN 07W-12W.
ISOLATED SHOWERS ARE ELSEWHERE FROM 02N-05N BETWEEN 18W-
24W...05S-01N BETWEEN 26W-30W AND FROM 02S-03N W OF 35W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYER TROUGH EXTENDING FROM THE GREAT LAKES ALONG THE
EASTERN CONUS WITH A BASE INTO THE EASTERN GULF SUPPORTS A
FRONTAL SYSTEM THAT EXTENDS FROM A 1011 MB LOW S OF PANAMA CITY
NEAR 29N85W. A COLD FRONT EXTENDS FROM THE LOW ALONG 25N85W
22N88W TO 21N91W WHERE IT TRANSITIONS INTO A SURFACE TROUGH TO
18N94W. A PARTIAL STATIONARY FRONT DEPARTS FROM THE LOW NE
ACROSS THE CENTRAL FLORIDA PANHANDLE AND THEN INTO GEORGIA WHERE
IT TRANSITIONS INTO A WARM FRONT. THERE ARE GALE FORCE WINDS AT
THE W-NW QUADRANTS OF THE LOW CENTER WHICH ARE EXPECTED TO
SUBSIDE LATER TONIGHT. PLEASE SEE SPECIAL FEATURE SECTION. THE
TROUGH ALOFT CONTINUES TO AMPLIFY AN UPPER RIDGE NOW ACROSS THE
WESTERN ATLC THUS INDUCING DIFFLUENT FLOW TO SUPPORT SCATTERED
MODERATE CONVECTION AND ISOLATED TSTMS E OF 86W...INCLUDING THE
FLORIDA PENINSULA. THE LOW WILL SHIFT SLOWLY NE...MOVING INLAND
ACROSS THE CENTRAL FLORIDA PANHANDLE TONIGHT...THEN WILL
CONTINUE NE TO EXIT THE GEORGIA COAST SAT AFTERNOON. THE
ASSOCIATED COLD FRONT WILL MOVE ACROSS THE FLORIDA PENINSULA
TONIGHT INTO SAT MORNING. IN ITS WAKE...A RIDGE WILL THEN EXTEND
ACROSS THE GULF THROUGH THE REMAINDER WEEKEND.

CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL RIDGING COVERS MUCH OF THE BASIN WITH
WATER VAPOR IMAGERY SHOWING DRY AIR SUBSIDENCE. THIS PATTERN
ALOFT IS PROVIDING OVERALL STABILITY ACROSS THE BASIN. A BROAD
SURFACE RIDGE COVERING THE CENTRAL AND SW N ATLC EXTENDS INTO
THE NORTHERN BASIN CREATING A TIGHTER PRESSURE GRADIENT TO
SUPPORT WINDS OF 20 KT ACROSS THE CENTRAL AND EASTERN BASIN. A
RELAXED PRESSURE GRADIENT OVER THE NW CARIBBEAN SEA SUPPORT
LIGHTER WINDS RANGING FROM 5-15 KT. THE MOIST AIRMASS FORMERLY
GENERATING SHOWERS ACROSS PUERTO RICO HAS MOVED INTO HISPANIOLA
AND NOW SUPPORT SHOWERS AND TSTMS THERE. CURRENTLY SATELLITE
IMAGERY SHOW THESE SHOWERS ARE CONCENTRATED OVER CENTRAL-WESTERN
DOMINICAN REPUBLIC AND HAITI. A LINE OF SHOWERS AND TSTMS IS
ALONG CUBA BEING ENHANCED BY LOW LEVEL MOISTURE CONVERGENCE. THE
HIGH PRES IS FORECAST TO MOVE SOUTH DURING THE NEXT 24 HOURS.
THIS PATTERN WILL MAINTAIN FRESH TO LOCALLY STRONG TRADES NEAR
THE COAST OF COLOMBIA WITH MODERATE TO LOCALLY FRESH TRADES
ELSEWHERE THROUGH SAT...WITH WINDS THEN WEAKENING SUN AS LOW
PRES MOVES N OF AREA AND THE HIGH PRES WEAKENS. A COLD FRONT
EXITING THE GULF SAT MORNING IS EXPECTED TO SUPPORT SHOWERS OVER
THE NW CARIBBEAN OVER THE WEEKEND.

...HISPANIOLA...
A LOW LEVEL MOIST AIRMASS PREVIOUSLY GENERATING SHOWERS ACROSS
PUERTO RICO HAS MOVED INTO HISPANIOLA AND ADJACENT WATERS TO
SUPPORT SHOWERS AND TSTMS CURRENTLY CONCENTRATED OVER CENTRAL-
WESTERN DOMINICAN REPUBLIC AND HAITI. A COLD FRONT MOVING OFF
THE GULF WATERS ON SAT MORNING WILL ADVECT MOISTURE INTO THE
REGION THUS INCREASING THE CHANCES OF RAIN SUN INTO MONDAY.

ATLANTIC OCEAN...
A BROAD SURFACE RIDGE ANCHORED BY A 1032 MB HIGH NEAR 34N54W
COVERS THE CENTRAL AND SW N ATLC BEING SUPPORTED BY A BROAD
RIDGE ALOFT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THE
SW N ATLC N OF 25N W OF 76W ASSOCIATED WITH A FRONTAL SYSTEM
CURRENTLY ANALYZED OVER THE EASTERN GULF OF MEXICO. A ZONE OF
DIFFLUENT FLOW ALOFT BETWEEN THE TROUGH SUPPORTING THE FRONT AND
THE RIDGE OVER THE W ATLC SUPPORTS THIS CONVECTION. OTHERWISE
OVER THE EASTERN ATLC...A SURFACE TROUGH EXTENDS FROM 30N26W TO
25N32W WITH NO CONVECTION ASSOCIATED WITH IT. FARTHER EAST...A
WEAK 1018 MB HIGH IS SITUATED NEAR 29N17W WHICH IS EXPECTED TO
DISSIPATE LATER TONIGHT.

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

$$
NR


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