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AXNT20 KNHC 220005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 21 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 FEATURES...

A 1009 MB LOW IS LOCATED 230 NM MILES EAST OF GUADELOUPE NEAR 16N58W...MOVING W AT 15-20 KT. A TROPICAL WAVE EXTENDS N FROM THE LOW CENTER TO 24N56W. HEAVY SHOWERS AND TSTMS ARE NW FROM THE LOW FROM 17N-21N BETWEEN 62W-64W. SCATTERED MODERATE CONVECTION IS FROM 14N-18N BETWEEN 56-60W AND ELSEWHERE FROM 14N- 23N BETWEEN 60W-67W. THIS AFTERNOON...HURRICANE HUNTER AIRCRAFT FOUND GALE FORCE WINDS IN THE NORTHERN SEMICIRCLE OF THE LOW EXPECTED TO LAST FOR THE NEXT 48 HOURS. GRADUAL DEVELOPMENT OF THE LOW IS POSSIBLE DURING THE NEXT FEW DAYS AS IT MOVES ACROSS THE LEEWARD ISLANDS...PUERTO RICO...AND THE BAHAMAS. INTERESTS DOWNSTREAM OF THE LOW SHOULD MONITOR CLOSELY THE PROGRESS OF THIS SYSTEM. CHANCES FOR DEVELOPMENT INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS HIGH.


...TROPICAL WAVES...

A TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 23N26W TO 12N26W MOVING W AT 10 KT. NO CONVECTION IS OCCURRING AT THIS TIME AS DRY SAHARAN AIR AND DUST ARE IN ITS ENVIRONMENT.

A TROPICAL WAVE IS EAST OF THE LEEWARD ISLANDS. SEE SPECIAL FEATURES SECTION.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W AND CONTINUES ALONG 13N26W 8N33W TO 7N40W. AN ITCZ EXTENDS FROM 7N40W TO 10N50W. SCATTERED MODERATE CONVECTION IS FROM 5N-14N E OF 22W AND FROM 5N-10N BETWEEN 44W-51W.


...DISCUSSION...

GULF OF MEXICO...

A 1019 MB HIGH IS CENTERED ON THE NE GULF NEAR 29N86W. A SCATTEREOMETER PASS SHOWS ANTICYCLONIC WINDS MAINLY BETWEEN 5-15 KT WITH SW WINDS UP TO 20 KT ACROSS THE BAY OF CAMPECHE. UPPER LEVEL DIFFUENCE AND LOW LEVEL MOISTURE ARE SUPPORTING SCATTERED SHOWERS AND HEAVY THUNDERSTORMS ON THE SE GULF S OF 25N E OF 89W. ISOLATED SHOWERS AND THUNDERSTORMS ARE LOCATED NEAR THE LOUISIANA COAST AND OVER THE YUCATAN. DURING THE NEXT 24 HOURS EXPECT SCATTERED SHOWERS AND THUNDERSTORMS MAINLY OVER THE SOUTHERN HALF OF THE BASIN.

CARIBBEAN SEA...

AN AREA OF LOW PRESSURE ASSOCIATED WITH A TRPCL WAVE IS EAST OF THE LEEWARD ISLANDS. THIS SYSTEM IS BRINGING HIGH MOISTURE INTO THE EASTERN CARIBBEAN AND ADJACENT WATERS. MIDDLE LEVEL DIVERGENCE ALONG WITH DEEP LAYER MOISTURE ASSOCIATED WITH THIS SYSTEM IS SUPPORTING THE CONVECTION DESCRIBED IN THE SPECIAL FEATURES SECTION. SEE ABOVE. AN ELONGANTED UPPER LEVEL LOW EXTENDS ACROSS THE CENTRAL AND SW CARIBBEAN ENHANCING SHOWERS AND ISOLATED TSTMS ON JAMAICA AS WELL AS S OF 13N BETWEEN 73W- 83W. UPPER LEVEL DIFFLUENCE ACROSS THE NW BASIN ENHANCES HEAVY SHOWERS AND TSTMS ALONG SOUTHERN CUBA AND ADJACENT WATERS. SCATTERED HEAVY SHOWERS AND TSTMS ARE ALSO NOTED OVER HAITI. FAIR WEATHER IS ELSEWHERE ACROSS THE BASIN BEING SUPPORTED BY DEEP LAYER DRY AIR AND/OR STRONG ENVIRONMENTAL SHEAR ON THE CENTER CARIBBEAN. TRADE WINDS OF 10-15 KT ARE ACROSS THE REGION...EXCEPT ALONG COLOMBIA WHERE WINDS INCREASE UP TO 20 KT. RAINSHOWERS ASSOCIATED WITH THE SYSTEM ON THE SPECIAL FEATURES WILL BE AFFECTING THE GREATER ANTILLES OVER THE WEEKEND.


...HISPANIOLA...

LINGERING MOISTURE ASSOCIATED WITH THE PASSAGE OF A SURFACE TROUGH ALONG WITH A REGION OF UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER CENTRAL HAITI. RAINSHOWER ACTIVITY WILL INCREASE OVER THE WEEKEND...PEAKING EARLY ON SATURDAY AS THE SYSTEM ON SPECIAL FEATURES MOVES ACROSS/NEAR THE ISLAND.

ATLANTIC OCEAN...

MAINLY MIDDLE TO UPPER LEVEL RIDGING IS ACROSS THE BASIN N OF 24N WHICH IS SUPPORTING SURFACE RIDGING. GALE FORCE WINDS ARE CLOSE TO THE LEEWARD ISLANDS ASSOCIATED WITH THE SYSTEM IN THE SPECIAL FEATURES. SEE ABOVE.

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

$$ NAR/ASL

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