[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 09 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
1745 UTC.

...SPECIAL FEATURES...

TROPICAL STORM IGOR IS CENTERED NEAR 15.5N 25.4W AT 09/1800 UTC
OR ABOUT 65 NM NW OF BRAVA IN THE CAPE VERDE ISLANDS...MOVING NW
AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE
LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST AND ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. IGOR
IS EMBEDDED WITHIN AN AREA OF DEEP LEVEL MOISTURE AS INDICATED
ON TOTAL PRECIPITABLE WATER IMAGERY. THE SYSTEM REMAINS IN A
SHEAR ENVIRONMENT WITH THE CONVECTION DISPLACED TO THE W OF THE
EXPOSED LOW LEVEL CENTER. CLUSTERS OF SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION ARE FROM 12N-17N BETWEEN 25W-30W.

A SURFACE TROUGH WITH A LOW LEVEL CIRCULATION EMBEDDED IN IT IS
LOCATED SE OF THE WINDWARD ISLANDS ANALYZED FROM 15N59W CROSSING
THE LOW CENTER NEAR 12N60W CONTINUING SOUTH TO ABOUT 9N61W. THIS
SYSTEM IS EMBEDDED WITHIN A BROAD AREA OF DEEP LEVEL MOISTURE AS
INDICATED ON TOTAL PRECIPITABLE WATER IMAGERY...MOST LIKELY
RELATED TO MONSOONAL TROUGHINESS IN THIS GENERAL REGION. BROAD
CYCLONIC TURNING IS EVIDENT ON VISIBLE IMAGERY. SCATTERED
MODERATE TO STRONG CONVECTION IS S OF 15N BETWEEN 57W AND 63W.
ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR SOME GRADUAL
DEVELOPMENT AS THE LOW MOVES SLOWLY WESTWARD. THERE IS A MEDIUM
CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

...TROPICAL WAVES...

NO TROPICAL WAVES ARE OBSERVED OVER THE ATLANTIC ON THE 1200 UTC
SURFACE ANALYSIS.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM 9N27W CONTINUING WESTWARD ALONG
7N36W 8N46W TO 10N56W. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS WITHIN 80 NM ON EITHER SIDE OF THE ITCZ AXIS E OF
50W...WHILE SCATTERED STRONG CONVECTION IS OVER THE COASTAL
WATERS OF GUYANA...SURINAME...AND FRENCH GUIANA S OF 12N W OF
50W INCLUDING NORTHERN PORTIONS OF EASTERN VENEZUELA AND GUYANA.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES THAT MOST OF THE GULF REMAINS
UNDER THE INFLUENCE OF ANTI-CYCLONIC FLOW ALOFT PRODUCING
RELATIVELY STABLE CONDITIONS ACROSS THE REGION...EXCEPT FOR THE
NORTH CENTRAL GULF...WHERE A WEAK AREA OF SURFACE TROUGHINESS IS
GENERATING ISOLATED SHOWERS N OF 25N BETWEEN 86W AND 91W. AN
UPPER LEVEL LOW CURRENTLY OVER THE FAR NW CARIBBEAN SEA WILL
CROSS THE NORTHERN YUCATAN PENINSULA AND ENTER THE SW GULF OVER
THE NEXT 24 TO 36 HRS BRINGING WEAK CONVECTION. OTHERWISE...NO
SIGNIFICANT CHANGES ARE EXPECTED DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
AN UPPER LOW REMAINS CENTERED IN THE NW CARIBBEAN 120 NM EAST OF
THE YUCATAN PENINSULA NEAR 20N86W...PRODUCING CLOUDINESS AND
SCATTERED SHOWERS WEST OF 85W FROM 18N TO 21N. THIS UPPER
FEATURE WILL CONTINUE TO MOVE WESTWARD AND WOULD LIKELY EXIT THE
NW CARIBBEAN SEA OVER THE NEXT 12 HOURS. ELSEWHERE...THE REMNANT
OF GASTON...WHICH IS NOW AN OPEN TROUGH...IS GENERATING
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE NORTH
CENTRAL CARIBBEAN NORTH OF 15N BETWEEN 72W AND 79W. A NEAR
STATIONARY SURFACE TROUGH WITH A LOW CONNECTED TO IT NEAR 12N60W
IS PRODUCING CLOUDINESS...SHOWERS...AND THUNDERSTORMS OVER THE
FAR SOUTHEASTERN CARIBBEAN INCLUDING THE SOUTHERN WINDWARD
ISLANDS SOUTH OF DOMINICA EAST OF 65W. COMPUTER MODEL GUIDANCE
SUGGEST THE UNSTABLE WEATHER CONDITIONS WILL CONTINUE IN THIS
REGION OVER THE NEXT 24 HOURS. SEE SPECIAL FEATURES ABOVE FOR
MORE DETAILS REGARDING THIS SYSTEM. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE OVER THE SW BASIN OF 15N W OF
75W...ASSOCIATED WITH NEARBY CONVERGENCE IN THE VICINITY OF THE
MONSOONAL TROUGH. COMPUTER MODELS SUGGEST THIS AREA OF
CONVECTION WILL LINGER IN THIS REGION OVER THE NEXT 24 HOURS.
MEANWHILE DRY STABLE AIR ALOFT CONTINUES TO INTRUDE THE
NORTHEASTERN CARIBBEAN BRINGING MOSTLY STABLE ATMOSPHERIC
CONDITIONS N OF 15N E OF 71W.

ATLANTIC OCEAN...
THE PRIMARY CONCERN CONTINUES TO BE TROPICAL STORM IGOR LOCATED
ABOUT 65 NM NW OF BRAVA IN THE CAPE VERDE ISLANDS. FOR MORE
DETAILS REGARDING THIS STORM...SEE SPECIAL FEATURES ABOVE.
OTHERWISE...DRY STABLE AIR ALOFT COVERS THE REST OF THE
DISCUSSION AREA PROVIDED BY STRONG MID/UPPER LEVEL RIDGE
ESTABLISHED IN THE EASTERN ATLC SUPPORTING A SURFACE 1027 MB
HIGH EAST OF THE AZORES NEAR 37N19W...WITH SURFACE RIDGING AXIS
EXTENDING WSW ACROSS THE CENTRAL ATLANTIC TO NEAR 30N60W. A WEAK
SURFACE TROUGH IS BENEATH THE UPPER RIDGE MOVING ACROSS THE
CENTRAL ATLANTIC...ANALYZED FROM 23N40W TO 14N43W...GENERATING
SCATTERED SHOWERS FROM 14N TO 28N BETWEEN 37W AND 45W. THIS
SYSTEM WILL CONTINUE TO MOVE WESTWARD WITH CONVECTION OVER THE
NEXT 24 HOURS.

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

$$

SALMON/GARCIA



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