[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 290555
TWDAT

TROPICAL WEATHER DISCUSSION
NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN SEP 29 2013

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
0515 UTC.

...SPECIAL FEATURE...
THE 1014 MB LOW NEAR 25N50W WAS UPGRADED TO TROPICAL DEPRESSION
ELEVEN AT 29/0300 UTC. TROPICAL DEPRESSION ELEVEN IS CENTERED
NEAR 25.2N 50.2W AT 29/0300 UTC OR ABOUT ABOUT 835 NM E-NE OF
THE NORTHERN LEEWARD ISLANDS AND ABOUT 880 NM E-SE OF BERMUDA
MOVING N AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB.
MAXIMUM SUSTAIN WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. PLEASE
SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 KNHC AND THE FULL ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF LINE FROM
25N47W TO 28N52W.

...TROPICAL WAVES...
TROPICAL WAVE OVER THE CAPE VERDE ISLANDS EXTENDS FROM 18N25W TO
8N27W MOVING W NEAR 15 KT. WAVE REMAINS EMBEDDED WITHIN A SURGE
OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. CLUSTERS OF SCATTERED MODERATE/ISOLATED CONVECTION ARE
WITHIN 180 NM W OF THE WAVE BETWEEN 7N-13N WITH CLUSTERS OF
SCATTERED MODERATE CONVECTION WITHIN 120 NM EITHER SIDE OF THE
REMAINDER OF THE WAVE.

TROPICAL WAVE EXTENDS FROM 18N60W TO THE COAST OF VENEZUELA NEAR
8N60W MOVING W NEAR 15 KT. WEAKENING WAVE REMAINS WITHIN AN AREA
OF MODERATE MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
ARE WITHIN 60 NM OF THE WAVE.

TROPICAL WAVE IN THE E CARIBBEAN EXTENDS FROM 15N68W TO INLAND
OVER VENEZUELA TO 8N68W MOVING W NEAR 15 KT. THIS WAVE IS
RAPIDLY WEAKENING AND IS EMBEDDED WITH AN AREA OF DRY AIR AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. NO ASSOCIATED
SHOWERS/CONVECTION.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N17W ALONG 12N23W TO 8N30W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 7N45W TO SOUTH AMERICA NEAR 5N52W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE INLAND AND
WITHIN 90 NM ALONG THE COAST OF SW AFRICA BETWEEN LIBERIA AND
GUINEA...WITHIN 200 NM S OF THE MONSOON TROUGH/ITCZ BETWEEN 23W-
46W...FROM 7N-9N BETWEEN 30W-37W...AND FROM 6N-11N BETWEEN 45W-
55W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE DOMINATES MOST OF THE GULF ANCHORED ALONG
THE COAST NEAR GALVESTON TEXAS. A NARROW UPPER TROUGH EXTENDS
FROM THE BROAD UPPER TROUGH OVER THE FAR E GULF AND W ATLC ALONG
THE COAST OF MEXICO IN THE BAY OF CAMPECHE. THIS BROAD UPPER
TROUGH IS SUPPORTING A FRONTAL BOUNDARY IN THE W ATLC AND N
CARIBBEAN WITH A SHEAR LINE EXTENDING THROUGH THE YUCATAN
CHANNEL NEAR 22N85W TO 24N92W. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE WITHIN 45 NM OF THE SHEAR LINE. A
SURFACE RIDGE REMAINS ACROSS THE N GULF ANCHORED BY A 1027 MB
HIGH OVER NEW ENGLAND. SOME ISOLATED LOW LEVEL SHOWERS ARE OVER
THE NE GULF N OF 24N E OF 89W INCLUDING THE FLORIDA KEYS WHERE A
POSSIBLE ISOLATED THUNDERSTORM MAY OCCUR. WATER VAPOR IMAGERY
INDICATES DRY STABLE AIR COVERS ALL OF THE GULF KEEPING THE
REMAINDER OF THE AREA UNDER MOSTLY CLEAR SKIES TONIGHT. WEAK
SURFACE RIDGE WILL DOMINATE THE GULF THROUGH TUE. A BROAD TROUGH
WILL LIFT OUT OF THE NW CARIBBEAN INTO THE SE GULF LATE WED INTO
THU.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE FAR E GULF OF MEXICO DIPS S OVER THE
NW CARIBBEAN N OF LINE FROM THE WINDWARD PASSAGE TO THE TIP OF
NICARAGUA/HONDURAS SUPPORTING A COLD FRONT THAT EXTENDS FROM THE
W ATLC ACROSS CUBA NEAR HOLGUIN OVER THE ISLE OF YOUTH TO 22N85W
WHERE IT BECOMES A SHEAR LINE THROUGH THE YUCATAN CHANNEL AND
INTO THE GULF OF MEXICO. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 60 NM OF THE FRONT WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 45 NM OF THE
SHEAR LINE. AN UPPER RIDGE IS ANCHORED OVER SOUTH AMERICA
COVERING THE REMAINDER OF THE CARIBBEAN S OF HISPANIOLA W OF 66W
AND IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 16N-20N BETWEEN 70W-78W. A WEAK
SURFACE TROUGH IS BENEATH THIS UPPER RIDGE EXTENDING FROM 17N78W
ALONG 13N79W TO THE COAST OF PANAMA NEAR 9N79W. SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE S OF 17N BETWEEN
70W-83W. THE MONSOON TROUGH EXTENDS FROM COLOMBIA OVER PANAMA
CLIPPING THE FAR SW CARIBBEAN. AN UPPER LOW IS CENTERED OVER THE
LESSER ANTILLES NEAR 14N61W COVERING THE E CARIBBEAN. MODERATE
TO FRESH E TO SE TRADE WINDS ARE ACROSS S CENTRAL CARIBBEAN
THROUGH SUN WHILE GENTLE TO MODERATE WINDS PREVAIL ELSEWHERE
THROUGH THU. LOW PRESSURE ACROSS W ATLC WILL LIFT N SUN AND
ALLOW SURFACE RIDGE TO STRENGTHEN ACROSS NE CARIBBEAN THROUGH
WED. THE SURFACE TROUGH WILL DRIFT NW TOWARD THE NW CARIBBEAN
THROUGH WED.

HISPANIOLA...
CURRENTLY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 16N-
20N BETWEEN 70W-78W INCLUDING THE GULF OF GONAVE. SOUTHERLY FLOW
ALOFT THAT WILL CONTINUE THROUGH MON WHEN WINDS WILL SHIFT TO
WESTERLY THEN NORTHERLY ON TUE AS AN UPPER RIDGE MOVES ACROSS
THE N/CENTRAL CARIBBEAN AND BE W OF THE ISLAND BY WED. THIS WILL
INCREASE THE CHANCE OR INTENSIFY AFTERNOON SHOWERS AND
THUNDERSTORMS THROUGH MON. TUE THROUGH FRI WILL BE A SLIGHTLY
LESS CHANCE OF HEAVY AFTERNOON SHOWERS/THUNDERSTORMS.

ATLANTIC OCEAN...
THE HIGHLIGHT TONIGHT IS NEWLY DEVELOPED TROPICAL DEPRESSION
ELEVEN IN THE CENTRAL ATLC. SEE SPECIAL FEATURES ABOVE. AN UPPER
TROUGH COVERS THE W ATLC W OF 64W ACROSS FLORIDA AND DIPS S OVER
THE NW CARIBBEAN SUPPORTING A FRONTAL BOUNDARY THAT EXTENDS FROM
A 1008 MB LOW NEAR 29N68W WITH AN OCCLUDED FRONT EXTENDING TO A
TRIPLE POINT NEAR 31N66W AND THE COLD FRONT EXTENDING ALONG
26N68W THROUGH THE TURKS AND CAICOS TO ACROSS CUBA NEAR HOLGUIN
INTO THE NW CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS ARE
WITHIN 30/45 NM OF LINE FROM 26N67W TO 31N64W WITH SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 23N TO OVER THE GREATER
ANTILLES BETWEEN 67W-78W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOT THE REMAINDER OF THE W ATLC W OF THE FRONT. A
BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF THE
VIRGIN ISLANDS FROM 18N62W TO 23N61W. THE REMAINDER OF THE ATLC
IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH NEAR
26N39W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE TROPICAL
DEPRESSION ELEVEN. THE LOW 1008 MB WILL LIFT N AND EXIT THE
REGION SUN WITH THE FRONT LINGERING ACROSS THE BAHAMAS THROUGH
MON. A WEAK SURFACE RIDGE WILL DOMINATE THE W ATLC TUE THROUGH
THU.

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

$$
PAW


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