[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191143
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON SEP 19 2011

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...

A 1008 MB LOW IS EMBEDDED ALONG THE MONSOON TROUGH AXIS NEAR
12N37W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT
LOW-LEVEL MOISTURE IS MAXIMIZED FROM 06N-14N BETWEEN 34W-42W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
07N-15N BETWEEN 36W-40W. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE FOR THE DEVELOPMENT OF A TROPICAL DEPRESSION DURING
THE NEXT COUPLE OF DAYS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
10N25W TO THE SPECIAL FEATURES 1008 MB LOW NEAR 12N37W TO
09N48W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
FROM 11N-14N BETWEEN 23W-32W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 03N-08N BETWEEN 19W-30W...AND FROM 05N-12N
BETWEEN 30W-34W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN GULF NEAR 24N92W AND CONTINUES TO SUPPORT A SURFACE
RIDGE AXIS EXTENDING FROM THE SE CONUS OVER GEORGIA THROUGH
29N90W IN THE NORTH-CENTRAL GULF TO THE EAST-CENTRAL MEXICO
COAST NEAR 21N97W. PRIMARILY E TO SE SURFACE WINDS IN THE RANGE
OF 10-15 KT WERE NOTED ON AN EARLIER ASCAT PASS AROUND 19/0336
UTC AND THESE WINDS ARE EXPECTED TO PERSIST THROUGH MIDDAY
MONDAY. WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORTWAVE
TROUGH PROGRESSING ACROSS THE SOUTHERN U.S. PLAINS WHICH
SUPPORTS A FRONTAL BOUNDARY EXTENDING FROM EASTERN OKLAHOMA INTO
NORTH AND CENTRAL PORTIONS OF TEXAS. THIS FRONT IS FORECAST TO
ENTER NW PORTIONS OF THE GULF EARLY TUESDAY AND BEGIN TO
STALL...WHILE A REINFORCING FRONT WILL IMPACT THE NORTHERN GULF
BY THURSDAY. SOME WINDS OVER THE COASTAL WATERS OF THE TEXAS
COAST ARE AS OF 19/0900 UTC S TO SW WITH SCATTERED SHOWERS AND
TSTMS OCCURRING W OF A LINE FROM NEW ORLEANS LOUISIANA TO
BROWNSVILLE TEXAS. LOW-LEVEL MOISTURE AND POSSIBLE ISOLATED
LOW-TOPPED SHOWERS ARE PREVALENT ON SATELLITE IMAGERY THIS
MORNING ACROSS MUCH OF THE EASTERN GULF E OF 90W. A SURFACE
TROUGH IS ALSO ANALYZED IN THE BAY OF CAMPECHE FROM 21N92W TO
18N93W WITH ISOLATED SHOWERS OCCURRING S OF 20N BETWEEN 92W-95W.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 10N81W AND IS PROVIDING AN UPPER LEVEL
DIFFLUENT ENVIRONMENT W OF 74W WITH SCATTERED SHOWERS AND TSTMS
FOCUSED ON MAXIMIZED LOW-LEVEL SPEED CONVERGENCE ALONG THE COAST
OF CENTRAL AMERICA. ISOLATED SHOWERS ARE OCCURRING S OF 19N W OF
81W. E OF 74W...AN UPPER LEVEL TROUGH EXTENDS FROM THE SW NORTH
ATLC SOUTHWARD TO A BASE OVER THE SE CARIBBEAN. MIDDLE TO UPPER
LEVEL MOISTURE CONTINUES TO BE ADVECTED ACROSS THE MUCH OF THE
NE CARIBBEAN WITH ISOLATED SHOWERS AND TSTMS OCCURRING OVER THE
EASTERN CARIBBEAN E OF 65W. THE UPPER LEVEL TROUGHING WILL
BROADEN OUT THROUGH LATE TUESDAY OVER THE SW NORTH ATLC
PROVIDING THE EASTERN AND CENTRAL CARIBBEAN WITH CONTINUED WEST-
SOUTHWESTERLY FLOW AND HIGHER POSSIBILITY FOR WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS THROUGH WEDNESDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING OVER THE WESTERN
NORTH ATLC WITH AXIS ALONG 69W THAT SUPPORTS A COLD FRONT
EXTENDING INTO THE DISCUSSION AREA NEAR 32N71W TO 31N73W WHERE
THE FRONT BECOMES MORE DIFFUSE AS A DISSIPATING STATIONARY FRONT
TO THE FLORIDA PENINSULA NEAR DAYTONA BEACH. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF
THE FRONT W OF 70W. FARTHER TO THE SE...WATER VAPOR IMAGERY
INDICATES A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 24N67W.
MIDDLE TO UPPER LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD ON
THE EASTERN PERIPHERY OF THE LOW WITH WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS OCCURRING OVER THE AREA FROM 18N-29N BETWEEN
61W-71W. ISOLATED SHOWERS ARE ALSO OCCURRING EAST OF THE LESSER
ANTILLES FROM 13N-18N BETWEEN 58W-61W. THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A BROAD UPPER
LEVEL TROUGH DIPPING SOUTHWARD TO 15N BETWEEN 30W-45W. THIS
TROUGH SUPPORTS A SURFACE TROUGH EXTENDING INTO THE DISCUSSION
AREA NEAR 32N41W TO 30N42W WITH ISOLATED SHOWERS AND TSTMS
OCCURRING WITHIN 120 NM EITHER SIDE OF A LINE FROM 35N30W TO
27N42W. FARTHER SOUTH...A WEAK 1010 MB LOW IS CENTERED NEAR
17N47W THAT EXHIBITS A SMALL AREA OF SCATTERED MODERATE
CONVECTION WITHIN 90 NM OF THE CENTER OF THE LOW.

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

$$
HUFFMAN




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