[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED SEP 11 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 FEATURES...
TROPICAL STORM GABRIELLE IS CENTERED NEAR 32.2N 65.3W AT 11/0600
UTC OR ABOUT 35 NM W-SW OF BERMUDA MOVING N-NW AT 7 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SEE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ALL
DEEP CONVECTION IS WELL THE E-NE OF THE LOW CENTER. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 31N-34N BETWEEN 60W-
63W.

TROPICAL STORM HUMBERTO IS CENTERED NEAR 15.4N 28.4W AT 11/0300
UTC OR ABOUT 235 NM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS
MOVING NW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB.
MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SEE
LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 12N-15N BETWEEN 29W-
32W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
COVERS THE REMAINDER OF THE AREA FROM 10N-17N BETWEEN 25W-33W.

A BROAD AREA OF LOW PRESSURE OVER THE NW CARIBBEAN IS PRODUCING
A LARGE AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS. A
SURFACE TROUGH EXTENDS FROM THE YUCATAN CHANNEL NEAR 22N86W
ALONG 19N87W TO THE COAST OF HONDURAS NEAR 16N87W. THE SURFACE
TROUGH SHOULD MOVE OVER THE YUCATAN TODAY AND ENTER THE BAY OF
CAMPECHE ON THU. SOME DEVELOPMENT IS POSSIBLE AFTER THE SYSTEM
EMERGES OVER WATER AND THIS SYSTEM HAS A MEDIUM CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. LOCALLY
HEAVY RAINS AND GUSTY WINDS ARE POSSIBLE OVER BELIZE...
GUATEMALA...AND THE YUCATAN PENINSULA DURING THE NEXT DAY OR
TWO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 16N-22N W
OF 83W TO INLAND OVER THE YUCATAN PENINSULA AND CENTRAL AMERICA.

...TROPICAL WAVES...

TROPICAL WAVE ANALYZED IN THE CENTRAL ATLC IS NOW A SURFACE
TROUGH. SEE SECTION BELOW.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 17N16W TO 18N19W THEN RESUMES SW OF TROPICAL STORM
HUMBERTO NEAR 11N35W TO 8N43W WHERE THE ITCZ BEGINS AND
CONTINUES ALONG 7N49W TO 7N54W. THE MONSOON TROUGH HAS BEEN
DISRUPTED BY TROPICAL STORM HUMBERTO. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE FROM 6N-9N BETWEEN 32W-43W. THE 1013 MB
LOW...PREVIOUSLY A SURFACE LOW/TROPICAL WAVE IS CENTERED NEAR
18N47W WITH A SURFACE TROUGH EXTENDING NW ALONG 19N52W TO 21N56W
WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
FROM 16N-20N BETWEEN 44W-57W.

...DISCUSSION...

GULF OF MEXICO...
THE SHORTWAVE UPPER TROUGH THAT EXTENDS ACROSS E TEXAS CLIPS THE
NW GULF BETWEEN GALVESTON AND THE LOUISIANA/TEXAS BORDER. THE
UPPER LOW IN THE W ATLC EXTENDS AN UPPER TROUGH ACROSS FLORIDA
BETWEEN TAMPA AND CEDAR KEY COVERING THE E GULF N OF 23N E OF
90W. THIS IS INDUCING UPPER RIDGE THAT EXTENDS FROM THE YUCATAN
PENINSULA TO OVER SE LOUISIANA. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE ACROSS THE S GULF S OF 25N. A SURFACE
RIDGE EXTENDS FROM A 1022 MB HIGH OVER SOUTH CAROLINA TO OVER
THE N GULF. SURFACE RIDGE WILL PERSIST THROUGH THU. A SURFACE
TROUGH IN THE NW CARIBBEAN IS EXPECTED TO MOVE SLOWLY W-NW
ACROSS THE YUCATAN PENINSULA TONIGHT AND ENTER THE BAY OF
CAMPECHE ON THU. SEE SPECIAL FEATURES ABOVE.

CARIBBEAN SEA...
AN UPPER RIDGE IS ANCHORED OVER THE NW ATLC COVERING THE AREA W
OF 75W. THE SURFACE TROUGH IN THE NW CARIBBEAN IS IN THE SPECIAL
FEATURES ABOVE. THE UPPER RIDGE IS PROVIDING DIFFLUNCE ALOFT TO
GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ACROSS THE CENTRAL CARIBBEAN WITHIN 225 NM OF LINE FROM 11N77W
16N78W TO OVER CUBA NEAR 22N80W. THE MONSOON TROUGH EXTENDS FROM
COLOMBIA NEAR 9N76W OVER COSTA RICA NEAR 9N82W THEN NW OVER
NICARAGUA. AN UPPER LOW IS IN THE E CARIBBEAN NEAR 15N67W WITH
THE UPPER TROUGH COVERING THE REMAINDER OF THE CARIBBEAN.
MODERATE TO FRESH TRADE WINDS WILL CONTINUE ACROSS THE CENTRAL
AND E CARIBBEAN THROUGH THU WHILE GENTLE TO MODERATE TRADE WINDS
WILL PREVAIL ACROSS THE W CARIBBEAN.

HISPANIOLA...
SKIES ARE MOSTLY CLEAR ACROSS THE ISLAND TONIGHT WITH A POSSIBLE
ISOLATED SHOWER MOVING ACROSS THE E END OF THE DOMINICAN
REPUBLIC COMPLIMENTS OF THE EASTER TRADE WINDS. THE AFTERNOON
THUNDERSTORMS THAT DID DEVELOP OVER HAITI HAVE MOVED INTO THE
GULF OF GONAVE. ONCE THE UPPER LEVEL TROUGH PASSES TO THE W OF
HISPANIOLA THU...CLOUDINESS WILL GRADUALLY INCREASE WITH LOW
LEVEL SHOWERS AND THE POTENTIAL ONCE AGAIN FOR AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS WILL OCCUR.

ATLANTIC OCEAN...
THE PRIMARY CONCERNS FOR THE ATLC BASIN TONIGHT ARE TROPICAL
STORM GABRIELLE IN THE W ATLC AND TROPICAL STORM HUMBERTO IN THE
E ATLC. SEE SPECIAL FEATURES ABOVE. AN UPPER LOW IS CENTERED OFF
THE E COAST OF FLORIDA NEAR DAYTONA BEACH WITH AN UPPER TROUGH
COVERING THE W ATLC N 23N W OF 70W. CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS DOT THE W ATLC FROM 24N-32N W OF
72W INCLUDING THE BAHAMA ISLANDS. REMNANT TROUGHING AND MOISTURE
REMAIN IN THE WAKE OF GABRIELLE WITH A SURFACE TROUGH EXTENDING
FROM 29N68W ALONG 26N72W TO 24N75W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 21N-24N BETWEEN 73W-78W WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90/120 NM OF
LINE FROM 24N71W TO 31N63W. AN UPPER LOW IS IN THE E/CENTRAL
ATLC NEAR 26N41W GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS FROM 24N-30N BETWEEN 37W-46W. THE
REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1033 MB HIGH N OF THE AZORES. A WEAK PRESSURE PATTERN WILL
PREVAIL ACROSS THE MOST OF THE ATLC.

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

$$
PAW


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