[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051204
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU SEP 05 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...

TROPICAL STORM GABRIELLE IS CENTERED NEAR 17.7N 67.4W AT
05/1200 UTC...OR ABOUT 57 NM W-SW OF PONCE PUERTO RICO AND ABOUT
73 NM SE OF PUNTA CANA DOMINICAN REPUBLIC MOVING NW AT 7 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED
WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE THE LATEST
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.
GABRIELLE IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 3 TO
6 INCHES OVER PORTIONS OF PUERTO RICO...THE U.S. VIRGIN
ISLANDS...AND EASTERN PORTIONS OF THE DOMINICAN REPUBLIC WITH
ISOLATED MAXIMUM AMOUNTS OF UP TO 12 INCHES POSSIBLE IN AREAS OF
MOUNTAINOUS TERRAIN. THESE HEAVIER AMOUNTS COULD RESULT IN
DANGEROUS FLASH FLOODS AND MUD SLIDES OVER MOUNTAINOUS TERRAIN.
SCATTERED MODERATE TO STRONG CONVECTION IS FROM 15N-20N BETWEEN
62W-68W INCLUDING PORTIONS OF THE LEEWARD ISLANDS...THE VIRGIN
ISLANDS AND PUERTO RICO.

BROAD SURFACE LOW PRESSURE COVERS THE SOUTHWESTERN CORNER OF THE
GULF OF MEXICO. A SURFACE TROUGH EXTENDS FROM A 1012 MB LOW
PRESSURE CENTER THAT IS NEAR 19N91W AT THE COAST OF MEXICO...
TO 21N93W AND 24N94W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG
FROM 21N TO 24N BETWEEN 92W AND 95W. THE CLOUDINESS AND CONVECTIVE
PRECIPITATION THAT ARE AND HAVE BEEN IN THE SOUTHWESTERN CORNER
OF THE GULF OF MEXICO HAVE INCREASED COMPARATIVELY. FURTHER
DEVELOPMENT OF THIS SYSTEM IS POSSIBLE BEFORE IT MOVES INLAND
ALONG THE COAST OF MAINLAND MEXICO ON FRIDAY. THIS SYSTEM HAS
A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT
48 HOURS...AND A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 5 DAYS.

...TROPICAL WAVES...

TROPICAL WAVE W OF THE CAPE VERDE ISLANDS EXTENDS FROM 18N29W
THROUGH A 1012 MB LOW NEAR 14N31W TO 9N31W. WAVE HAS BEEN MOVING
W NEAR 10-15 KT FOR THE PAST 24 HOURS. WAVE IS EMBEDDED WITHIN A
BROAD SURGE OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE
WATER IMAGERY. WAVE IS WELL DEFINED IN THE SATELLITE WINDS WITH
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN
75 NM OF LINE FROM 17N27W 15N32W TO 10N34W.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 22N51W
TO 12N49W. WAVE HAS BEEN MOVING W 15-20 KT FOR THE PAST 24
HOURS. WAVE IS EMBEDDED WITHIN A CUT-OFF AREA OF DEEP MOISTURE
AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. NO ASSOCIATED
SHOWERS OR CONVECTION.

TROPICAL WAVE ENTERING THE E CARIBBEAN EXTENDS FROM 18N62W TO
11N62W. WAVE HAS BEEN MOVING W NEAR 10 KT FOR THE PAST 24 HOURS.
THE N PORTION OF THE WAVE HAS SPLIT AND IS NOW DEPICTED AS A
SURFACE TROUGH NE OF THE LEEWARD ISLANDS. WAVE IS EMBEDDED
WITHIN A BROAD AREA OF DEEP MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. SEE SPECIAL FEATURES ABOVE FOR
ACTIVITY IN THE VICINITY.

TROPICAL WAVE IN THE W CARIBBEAN EXTENDS FROM CUBA NEAR 21N79W
TO 10N78W. WAVE HAS BEEN MOVING NEAR 10 KT FOR THE PAST 24
HOURS. WAVE IS EMBEDDED WITHIN AN AREA OF MODERATE TO DEEP
MOISTURE THAT COVERS THE CARIBBEAN AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 17N77W TO 13N83W.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 17N16W AND CONTINUES ALONG 16N22W THROUGH THE
LOW/TROPICAL WAVE NEAR 14N31W TO 10N40W WHERE THE ITCZ BEGINS
AND CONTINUES ALONG 8N51W TO 9N59W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 200 NM ALONG THE
COAST OF AFRICA BETWEEN SIERRA LEONE THE S BORDER OF MAURITANIA.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE IS ANCHORED OVER S/CENTRAL MEXICO AND
EXTENDS AN AXIS THE GULF BETWEEN TUXPAN AND S FLORIDA.
A SURFACE TROUGH EXTENDS FROM A 1012 MB LOW PRESSURE CENTER THAT
IS NEAR 19N91W AT THE COAST OF MEXICO...TO 21N93W AND 24N94W.
DEEP MOISTURE COVERS MOST OF THE GULF AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 22N-25N BETWEEN 87W-95W WITH ISOLATED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS DOTTING THE REMAINDER OF THE
AREA S OF 28N FROM FLORIDA TO MEXICO. A BROAD UPPER TROUGH
COVERS THE NE GULF AND INTO THE W ATLC SUPPORTING A STATIONARY
BOUNDARY THAT REMAINS INLAND OVER THE SE CONUS. THE LOW/SURFACE
TROUGH WILL PREVAIL ACROSS THE BAY OF CAMPECHE AND SW GULF
THROUGH MON. TROPICAL WAVE WILL MOVE INTO THE SW GULF MON.

CARIBBEAN SEA...
PRIMARY CONCERN THIS MORNING IS TROPICAL STORM GABRIELLE AND THE
ACCOMPANYING RAINFALL. SEE SPECIAL FEATURES ABOVE. THE UPPER
RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN N OF 15N W
OF 82W. THE UPPER RIDGE ASSOCIATED WITH TROPICAL STORM GABRIELLE
DOMINATES THE E CARIBBEAN E OF 77W. THIS IS INDUCING AN INVERTED
TROUGH THAT EXTENDS FROM N COSTA RICA/SE NICARAGUA TO OVER CUBA
NEAR 21N79W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOT THE N CARIBBEAN N OF 18N BETWEEN 75W-84W AND
FROM 13N-18N BETWEEN 69W-75W. THE MONSOON TROUGH EXTENDS ACROSS
THE SW CARIBBEAN FROM COLOMBIA NEAR 10N75W TO ACROSS PANAMA/
COSTA RICA NEAR 9N84W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE S OF 13N BETWEEN 75W-78W AND S OF 10N BETWEEN
78W-82W. THE ACTIVITY OVER THE E CARIBBEAN IS DUE TO TROPICAL
STORM GABRIELLE. GABRIELLE IS EXPECTED TO MOVE THROUGH THE MONA
PASSAGE LATE TODAY. THE W CARIBBEAN TROPICAL WAVE WILL CONTINUE
W AND MOVE W OF THE AREA LATE FRI. THE E CARIBBEAN TROPICAL WAVE
WILL CONTINUE W REACHING THE CENTRAL CARIBBEAN ON SAT AND SUN
AND CONTINUE THROUGH THE W CARIBBEAN ON MON AND TUE.

HISPANIOLA...
SATELLITE IMAGERY INDICATES SOME POSSIBLE ISOLATED SHOWERS ARE
ACROSS THE DOMINICAN REPUBLIC THIS MORNING. TROPICAL STORM
GABRIELLE IS EXPECTED TO MOVE THROUGH THE MONA PASSAGE LATE
TODAY. THIS WILL GIVE THE DOMINICAN REPUBLIC MOST OF THE HEAVY
RAINFALL STARTING LATER THIS AFTERNOON. THE TROPICAL WAVE IN THE
E CARIBBEAN WILL MOVE S OF THE ISLAND SAT AND SUN. GABRIELLE IS
EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 3 TO 6 INCHES OVER
THE EASTERN PORTIONS OF THE DOMINICAN REPUBLIC WITH ISOLATED
MAXIMUM AMOUNTS OF UP TO 12 INCHES POSSIBLE IN AREAS OF
MOUNTAINOUS TERRAIN. THESE HEAVIER AMOUNTS COULD RESULT IN
DANGEROUS FLASH FLOODS AND MUD SLIDES OVER MOUNTAINOUS TERRAIN.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE NE GULF OF MEXICO EXTENDS OVER THE FAR
W ATLC N OF 27N W OF 68W SUPPORTING A FRONTAL BOUNDARY THAT IS N
OF THE DISCUSSION AREA. ISOLATED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM ACROSS FLORIDA
NEAR VERO BEACH TO BEYOND 30N72W AND SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 60 NM OF LINE FROM 30N72W TO BEYOND 32N67W.
AN UPPER LOW COVERS THE REMAINDER OF THE W ATLC INTO THE CENTRAL
ATLC N OF 24N CENTERED NEAR 28N60W. A SECOND WEAKER UPPER LOW IS
CENTERED NEAR 26N43W. A SURFACE TROUGH...PREVIOUSLY THE N
PORTION OF THE E CARIBBEAN TROPICAL WAVE...EXTENDS FROM 20N61W
TO 26N57W WITH SCATTERED SHOWERS WITHIN 150 NM EITHER SIDE OF
THE TROUGH. THE UPPER RIDGE ASSOCIATED WITH TROPICAL STORM
GABRIELLE EXTENDS AN AXIS NE ALONG 20N58W ALONG 26N52W TO 31N52W
WHICH IS PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60/75 NM OF LINE
FROM 26N51W ALONG 29N55W TO 30N62W. THE REMAINDER OF THE ATLC IS
DOMINATED BY A SURFACE RIDGE ANCHORED BY A WEAK 1020 M B HIGH IN
THE W ATLC NEAR 29N73W A 1025 MB HIGH IN THE CENTRAL ATLC NEAR
34N50W AND A 1026 MB HIGH IN THE E ATLC NEAR 36N302W. TROPICAL
STORM GABRIELLE IS EXPECTED TO MOVE INTO THE W ATLC THROUGH THE
MONA PASSAGE LATE THU CONTINUING TO MOVE NORTHWARD E OF THE
TURKS AND CAICOS BEFORE NE ON SUN THEN N OF THE AREA ON TUE. A
WEAK COLD FRONT WILL DIP INTO THE N/CENTRAL WATERS TODAY BEFORE
WEAKENING TO A TROUGH ON FRI THEN SHIFT E AND STRENGTHEN OVER
THE CENTRAL ATLC OVER THE WEEKEND.

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

$$
PAW


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