[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 11 2010

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM IGOR IS CENTERED NEAR 17.4N 39.5W AT 11/1500 UTC
OR ABOUT 895 NM W OF THE CAPE VERDE ISLANDS AND ABOUT 1275 NM E
OF THE LEEWARD ISLANDS MOVING W AT 17 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 995 MB. MAXIMUM SUSTAINED WIND SPEED IS 60
KT WITH GUSTS TO 75 KT. GRADUAL INTENSIFICATION OF IGOR IS
FORECAST OVER THE NEXT FEW DAYS AS IT TRACKS ON THE SOUTHERN
PERIPHERY OF A CENTRAL ATLANTIC UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTERED NEAR 23N46W. VISIBLE SATELLITE IMAGERY ALSO
INDICATES A BANDING EYE FEATURE WITH SCATTERED STRONG CONVECTION
WITHIN 60 NM OF THE CENTER. ELSEWHERE SCATTERED MODERATE
CONVECTION IS FROM 14N-18N BETWEEN 38W-44W...LOCATED MAINLY
WITHIN THE SW QUADRANT. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

A 1009 MB SURFACE LOW PRESSURE IS CENTERED IN THE EASTERN
CARIBBEAN SEA NEAR 14N64W MOVING W AT 10 TO 15 KT. BROAD
LOW-LEVEL CYCLONIC FLOW IS LOCATED IN THE CARIBBEAN BETWEEN
60W-70W ALONG WITH A FAVORABLE UPPER LEVEL DIFFLUENT ENVIRONMENT
DUE TO AN UPPER LEVEL ANTICYCLONE NEAR 18N67W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION COVERS A LARGE AREA FROM
11N-18N BETWEEN 62W-70W...INCLUDING PORTIONS OF THE US/UK VIRGIN
ISLANDS AND PUERTO RICO. IT IS POSSIBLE THAT A TROPICAL
DEPRESSION MAY FORM DURING THE NEXT FEW DAYS AS THE SYSTEM MOVES
TOWARD THE CENTRAL AND WESTERN CARIBBEAN SEA.

A TROPICAL WAVE IS FROM 08N TO 19N ALONG 15W MOVING W AT 10 TO
15 KT. A 1008 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 13N15W
WITH METEOSAT-9 VISIBLE SATELLITE IMAGERY INDICATING BROAD
CYCLONIC FLOW IN THE LOW-LEVEL CLOUD FIELD EXTENDING FROM
INTERIOR W AFRICA ALONG 08W WESTWARD INTO THE EASTERN ATLC ALONG
27W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
09N-16N BETWEEN 13W-22W. AS THE WAVE MOVES OUT OVER THE OPEN
WATERS OF THE EASTERN TROPICAL ATLC AND INTERACTS WITH W-SW
MONSOONAL FLOW ALREADY IN PLACE FROM 06N-11N BETWEEN 15W-27W...
FURTHER ORGANIZATION OF CONVECTION IS ANTICIPATED WITH THE
POSSIBILITY OF TROPICAL CYCLONE DEVELOPMENT OVER THE NEXT COUPLE
OF DAYS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 08N18W 10N25W 15N31W THEN RESUMES
NEAR 14N49W 11N55W 13N62W 12N75W THEN TO WESTERN PANAMA NEAR
09N82W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 04N-10N
BETWEEN 10W-30W. SCATTERED MODERATE CONVECTION IS FROM 06N-13N
BETWEEN 36W-44W...AND FROM 05N-10N BETWEEN 50W-61W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS LOCATED OVER WEST
TEXAS CENTERED NEAR 31N103W AND IS PROVIDING MUCH OF THE GULF
AND FLORIDA PENINSULA WITH NORTHEAST TO EAST UPPER LEVEL FLOW
AND MODERATELY DRY AIR. THIS OVERALL SUBSIDENT ENVIRONMENT IS
SUPPORTING A WEAK SURFACE RIDGE AXIS FROM NORTHERN FLORIDA
THROUGH 27N88W TO THE YUCATAN PENINSULA. FAIR SKIES DOMINATE N
OF 22N WITH ONLY A FEW ISOLATED SHOWERS AND TSTMS LOCATED OVER
THE SE GULF AND FLORIDA STRAITS S OF 25N E OF 85W. ALSO A FEW
ISOLATED SHOWERS ARE OCCURRING OVER THE WESTERN BAY OF CAMPECHE
S OF 22N W OF 94W DUE TO AN UPPER LEVEL LOW CENTERED INLAND OVER
CENTRAL MEXICO NEAR 21N101W.

CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW ORIGINATING FROM AN UPPER LEVEL
HIGH CENTERED OVER WEST TEXAS IMPACTS THE WESTERN CARIBBEAN W OF
77W WITH NORTHEASTERLY UPPER LEVEL FLOW. OVERALL THIS AIRMASS IS
COMPRISED OF MODERATELY DRY AIR AND MOSTLY FAIR SKIES ARE FOUND
OVER CUBA...JAMAICA AND INTERIOR PORTIONS OF CENTRAL AMERICA
THIS AFTERNOON. HOWEVER...A SURFACE TROUGH IS ANALYZED FROM
09N80W TO 18N83W DUE TO BROAD CYCLONIC LOW-LEVEL FLOW EMBEDDED
WITHIN THE TRADES. THIS MARGINAL CONVERGENCE IS GENERATING
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE WESTERN
CARIBBEAN S OF 19N W OF A LINE FROM GRAND CAYMAN ISLAND TO
NORTHERN COLOMBIA NEAR 11N74W. ELSEWHERE...THE SPECIAL FEATURE
LOW PRESSURE AREA IMPACTS THE EASTERN CARIBBEAN E OF 72W AND IS
OCCURRING BENEATH AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED NEAR 18N67W. SCATTERED SHOWERS AND TSTMS COVER A LARGE
AREA FROM 11N-18N BETWEEN 62W-70W...INCLUDING PORTIONS OF THE
US/UK VIRGIN ISLANDS AND PUERTO RICO. ISOLATED SHOWERS LINGER
EAST OF THIS AREA OVER MANY OF THE LESSER ANTILLES AND ADJACENT
COASTAL WATERS.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH IS LOCATED OVER THE WATERS OF THE WESTERN
ATLC OCEAN WITH AXIS FROM 35N65W TO 27N69W. THIS UPPER LEVEL
TROUGHING SUPPORTS A COLD FRONT FROM BERMUDA NEAR 33N65W TO
31N72W THEN CONTINUING WESTWARD AS A STATIONARY FRONT TO 31N77W
AND INLAND NEAR SAVANNAH GEORGIA. ISOLATED SHOWERS ARE PRIMARILY
FOCUSED WITHIN 60 NM OF THE FRONTAL BOUNDARY AND N OF 27N
BETWEEN 62W-75W. FARTHER SE...A WEAK SURFACE TROUGH IS ANALYZED
WEST OF TROPICAL STORM IGOR FROM 16N47W TO 20N51W TO 26N51W.
POSSIBLE ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE
TROUGH AXIS. ATMOSPHERIC ENERGY FRACTURED NORTH AWAY FROM THE
SURFACE TROUGH OVER THE PAST 24 HOURS HAS RESULTED IN A 1017 MB
LOW CENTERED NEAR 29N49W. THIS LOW REMAINS EMBEDDED WITHIN BROAD
SURFACE RIDGING OVER THE CENTRAL AND EASTERN ATLC WITH SCATTERED
SHOWERS AND ISOLATED TSTMS OCCURRING FROM 29N-33N BETWEEN 47W-
51W. ELSEWHERE...SURFACE RIDGING DOMINATES N OF 24N E OF 45W
WITH STRONG NE WINDS 20 TO 25 KT NOTED ON AN EARLIER MORNING
ASCAT PASS WITHIN 240 NM OF THE W AFRICA COAST FROM 19N-23N.

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

$$
HUFFMAN




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