Tropical Weather Discussion
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000
AXNT20 KNHC 062342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

DISORGANIZED SHOWERS AND THUNDERSTORMS EXTENDING N FROM THE
BAHAMA ISLANDS TO NORTH CAROLINA ASSOCIATED WITH THE UPPER
TROUGH OVER THE FLORIDA PENINSULA AND A WEAK SURFACE LOW/TROUGH
A COUPLE DO HUNDRED MILES E OF THE FLORIDA. PLEASE SEE ATLANTIC
SECTION BELOW. CONDITIONS ARE EXPECTED TO BECOME GRADUALLY MORE
FAVORABLE FOR DEVELOPMENT OVER THE NEXT DAY OR SO AS THE SYSTEM
MOVES SLOWLY NORTHWARD THEN NORTHWESTWARD. THERE IS A MEDIUM
CHANCE OF FORMATION OF THIS SYSTEM INTO A SUB-TROPICAL OR
TROPICAL CYCLONE OVER THE NEXT 48 HOURS. REGARDLESS OF
DEVELOPMENT...HEAVY RAIN IS POSSIBLE OVER PORTIONS OF THE
COASTAL SE CONUS BEGINNING THU.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 15N17W ALONG 9N18W TO 4N22W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 3N30W 2N38W TO SOUTH AMERICA NEAR 1N49W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-8N
BETWEEN 16W-20W...FROM 2N-5N BETWEEN 23W-30W...WITHIN 60 NM S OF
THE ITCZ BETWEEN 32W-35W...AND FROM 2N-4N W OF 48W TO INLAND
OVER SOUTH AMERICA. SMALL CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE WITHIN 30/45 NM OF LINE FROM 3N6W
TO 4N11W.

...DISCUSSION...

GULF OF MEXICO...
A SHARP UPPER TROUGH EXTENDS FROM OVER THE SE CONUS ACROSS THE
FLORIDA PENINSULA AND INTO THE NW CARIBBEAN ACROSS W CUBA
COVERING THE E GULF OF MEXICO AND THE FAR W ATLC. AN UPPER RIDGE
ANCHORED IN THE E PACIFIC REGION EXTENDS A RIDGE AXIS ACROSS
MEXICO TO OVER THE MID/LOWER MISSISSIPPI VALLEY. A SURFACE RIDGE
EXTENDS FROM A 1022 MB HIGH OVER E KENTUCKY INTO THE GULF OVER
PENSACOLA FLORIDA TO NEAR 25N91W. CONVERGENCE OF THE SE SURFACE
FLOW AND THE NE FLOW ALOFT ARE GENERATING ISOLATED SHOWERS/
THUNDERSTORMS N OF 26N TO THE N GULF COAST BETWEEN 88W-92W.
VISIBLE SATELLITE IMAGERY AND NESDIS HMS FIRE AND SMOKE ANALYSIS
INDICATES THE SW GULF IS COVERED LIGHT TO MEDIUM SMOKE MAINLY S
OF 26N W OF 93W LEAVING THE REMAINDER OF THE GULF WITH FAIR
WEATHER THIS EVENING. HIGH PRESSURE WILL PREVAIL OVER THE AREA
THROUGH TO WEEKEND. A SURFACE TROUGH WILL MOVE WESTWARD OFF THE
YUCATAN PENINSULA AND ACROSS THE E BAY OF CAMPECHE DURING THE
EVENINGS.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE FLORIDA PENINSULA EXTENDS INTO THE
CARIBBEAN ACROSS W CUBA NEAR HAVANA ALONG THE COAST OF CENTRAL
AMERICA TO COSTA RICA/W PANAMA. UPPER LEVEL DIFFLUENCE ON THE E
SIDE OF THE UPPER TROUGH COUPLED WITH LINGERING LOW LEVEL
MOISTURE IS GENERATING SCATTERED TO NUMEROUS SHOWERS/SCATTERED
THUNDERSTORMS INLAND OVER CUBA. SATELLITE IMAGERY SHOWS THE
SAHARAN AIR LAYER EXTENDS INTO THE CARIBBEAN TO NEAR 83W. THE
LEADING EDGE OF THIS LAYER COMBINED WITH THE UPPER TROUGH IS
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM
OF LINE FROM 20N83W TO OVER THE NE NICARAGUA/NE HONDURAS NEAR
15N84W. ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE SW CARIBBEAN S
OF 11N W OF 80W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN
UNDER FAIR SKIES THIS EVENING. FRESH TO STRONG TRADE WINDS WILL
PREVAIL OVER MUCH OF THE CARIBBEAN THROUGH FRI THEN EXPAND
WESTWARD FRI NIGHT THROUGH THE WEEKEND.

...HISPANIOLA...
MOSTLY FAIR SKIES ARE ACROSS THE ISLAND THIS EVENING WITH SOME
POSSIBLE ISOLATED LOW LEVEL SHOWERS ACROSS PORTIONS OF HAITI.
SOUTHERLY FLOW ALOFT WITH LIMITED MOISTURE AND THE SAHARAN AIR
LAYER WILL KEEP SKIES MOSTLY CLEAR ACROSS THE ISLAND THROUGH
LATE THU ALTHOUGH SOME ISOLATED SHOWERS LOW LEVEL SHOWERS COULD
DEVELOP OVER THE HIGHER TERRAIN ON HAITI THROUGH THU. MOISTURE
WILL BEGIN TO INCREASE LATE THU/EARLY FRI BRINGING MORE SHOWERS
FOR LATE IN THE WEEK.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE FLORIDA PENINSULA AND INTO THE NW
CARIBBEAN COVERS THE W ATLC W OF 78W. AN UPPER RIDGE TO THE E
EXTENDS FROM 26N63W TO BEYOND 32N72W AND IS BEING AMPLIFIED THIS
UPPER TROUGH. BENEATH IS THE SPECIAL FEATURES THAT CONSIST OF A
SURFACE TROUGH THAT EXTENDS FROM 31N77W TO A 1015 MB LOW NEAR
28N79W TO 24N79W. UPPER LEVEL DIFFLUENCE ON THE SW SIDE OF THE
UPPER RIDGE IS GENERATING A BROAD AREA OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 23N77W ACROSS
THE BAHAMA ISLANDS TO 32N74W. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE W OF THE ABOVE ACTIVITY TO INLAND
OVER FLORIDA. A SURFACE RIDGE COVERS THE REMAINDER OF THE W AND
MOST OF THE CENTRAL ATLC ANCHORED BY A 1027 MB HIGH NEAR 32N54W
AND EXTENDING A RIDGE AXIS NW TO THE 1022 MB HIGH OVER E
KENTUCKY AND SE TO 25N35W. AN UPPER TROUGH OVER THE NE ATLC IS
SUPPORTING A COLD FRONT THAT ENTERS THE E ATLC NEAR 32N20W
EXTENDING ALONG 23N33W TO 22N51W. THE W ATLC LOW IS FORECAST TO
MOVE SLOWLY NORTHWARD THROUGH FRI...POSSIBLY DEVELOPING INTO A
SUBTROPICAL OR TROPICAL CYCLONE...BEFORE LIFTING N OF THE AREA
LATE THU NIGHT. IN ITS WAKE THE CENTRAL ATLC HIGH PRESSURE WILL
BUILD WESTWARD ACROSS THE BASIN THROUGH THE WEEKEND.

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

$$
PAW



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