[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

HURRICANE IGOR IS CENTERED NEAR 31.9N 65.7W AT 20/0000 UTC OR
ABOUT 60 MI WSW OF BERMUDA MOVING NNE AT 12 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 953 MB. MAXIMUM SUSTAINED WIND SPEED
IS 65 KT WITH GUSTS TO 85 KT. IGOR REMAINS LARGE AND TROPICAL
STORM CONDITIONS ARE ALREADY IMPACTING BERMUDA. THE CENTER WILL
PASS NEAR OR OVER BERMUDA OVER THE NEXT HOUR OR SO. SEE LATEST
NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. NUMEROUS
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 31N-36N BETWEEN
63W-69W.

TROPICAL STORM JULIA IS CENTERED NEAR 34.8N 49.7W AT 19/2100 UTC
OR ABOUT 1280 MI W OF THE AZORES MOVING NE AT 12 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WIND
SPEED IS 40 KT WITH GUSTS TO 50 KT. WEAKENING IS EXPECTED AS
JULIA MOVES ENE OVER COOLER WATERS AND CONTINUES TO EXPERIENCE
WIND SHEAR FROM THE OUTFLOW OF HURRICANE IGOR OVER THE NEXT
SEVERAL DAYS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. NUMEROUS
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 32N-37N BETWEEN
41W-50W.

AN AREA OF LOW PRESSURE IS LOCATED WSW OF THE CAPE VERDE ISLANDS
CONCENTRATED NEAR A 1008 MB LOW NEAR 15N31W MOVING W NEAR 5-10
KT. AN AREA OF DEEP LAYERED MOISTURE SURROUNDS THE SURFACE LOW
NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS FROM 11N-18N BETWEEN 84W AND 35W.
ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR A TROPICAL DEPRESSION
TO FORM DURING THE NEXT DAY OR SO AS THIS SYSTEM MOVES SLOWLY
NORTHWESTWARD. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...ITCZ...

A MONSOONAL TROUGH IS ANALYZED OFF THE W AFRICAN COAST ALONG
11N15W 9N18W TO 11N24W...RESUMING OVER THE CAPE VERDE ISLANDS
NEAR 18N24W SW ALONG 14N32W 11N36W TO 11N43W. SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS FROM 5N TO 11N BETWEEN THE
COAST OF AFRICA AND 25W. SIMILAR CONVECTION IS FROM 10N TO 18N
BETWEEN 28W AND 42W. A SURFACE LOW IS EMBEDDED IN THIS AREA OF
MONSOONAL TROUGHINESS NEAR 15N31W. SEE SPECIAL FEATURES ABOVE
FOR MORE DETAILS. A TRADITIONAL SURFACE TROUGH IS ANALYZED FROM
13N49W TO 5N54W. SCATTERED MODERATE CONVECTION IS WITHIN 80 NM
ON EITHER SIDE OF THE TROUGH AXIS N OF 9N.

...DISCUSSION...

GULF OF MEXICO...
A MID/UPPER LEVEL RIDGE OF HIGH PRESSURE IS OVER THE GULF WITH
ANTI-CYCLONIC FLOW ALOFT CENTERED OVER THE CENTRAL GULF. A WEAK
SUBTROPICAL JET STREAK MOVES AROUND THE NORTHERN PORTION OF THE
ANTI-CYCLONIC FLOW COVERING THE NORTHERN HALF OF THE GULF. THE
REAR-RIGHT QUADRANT OF THIS UPPER LEVEL FEATURE ALONG WITH DEEP
LAYER MOISTURE AND INSTABILITY ACROSS THE NW GULF SUPPORT A
NEARLY STATIONARY SURFACE TROUGH THAT LINES UP 75 NM OFF THE
TEXAS AND MEXICO COAST FROM 27N95W SOUTHWARD TO 23N96W. THE
SYSTEM IS PRODUCING SCATTERED HEAVY SHOWERS AND THUNDERSTORMS
ACROSS THE TEXAS COASTAL WATERS N OF 25N W OF 92W. COMPUTER
MODELS SUGGEST THIS AREA OF CONVECTION WILL LINGER THROUGH THE
MIDDLE OF NEXT WEEK. FAIR WEATHER CONDITIONS ARE ELSEWHERE
ACROSS THE BASIN.

CARIBBEAN SEA...
TOTAL PRECIPITABLE WATER IMAGERY DISPLAYS A STREAM OF DEEP LAYER
MONSOONAL MOISTURE MOVING N ACROSS THE EASTERN CARIBBEAN. THE
MOISTURE FLOW IS DUE TO THE LARGE SCALE CYCLONIC WIND FIELD LEFT
FROM HURRICANE IGOR. THIS SCENARIO IS GENERATING SCATTERED
SHOWERS AND THUNDERSTORMS E OF 67W INCLUDING THE LEEWARD ISLANDS
AND PUERTO RICO AS NOTED BY SATELLITE DATA AND DOPPLER RADAR
IMAGERY. COMPUTER MODELS SUGGEST THE CONVECTION IS THIS REGION
WILL LINGER OVER THE NEXT 24 TO 36 HOURS. SCATTERED MODERATE
CONVECTION IS ALSO OVER THE SOUTH CENTRAL AND SW CARIBBEAN S OF
14N W OF 70W DUE TO CLOSE PROXIMITY TO MONSOONAL TROUGH
EXTENDING ACROSS THIS REGION. FAIR WEATHER CONDITIONS WITH A FEW
ISOLATED SHOWERS ARE OBSERVED ELSEWHERE ACROSS THE BASIN...DUE
TO A DRY AND STABLE AIRMASS ALOFT CAPTURED ON WATER VAPOR
IMAGERY.

ATLANTIC OCEAN...
STRONG SUBSIDENCE OF AIR ALOFT IS NOTED ON WATER VAPOR IMAGERY
MOVING S ACROSS THE WESTERN ATLC W OF 70W BRINGING A VERY DRY
AND STABLE AIRMASS TO THIS REGION. HURRICANE IGOR IS TO THE EAST
OF THIS DRY AIRMASS...CURRENTLY IMPACTING THE ISLAND OF BERMUDA.
TROPICAL STORM JULIA IS TO THE ENE OF IGOR OVER OPEN WATERS. SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS ON BOTH SYSTEMS. THE
LARGE SCALE CYCLONIC WIND FIELD FROM HURRICANE IGOR IS DRAWING A
STREAM OF DEEP LAYER MONSOONAL MOISTURE NORTH ACROSS THE EASTERN
CARIBBEAN AND THE LESSER ANTILLES INTO THE ATLC. ALTHOUGH THE
HEAVIEST ACTIVITY IS CURRENTLY OVER THE E CARIBBEAN...SCATTERED
SHOWERS AND THUNDERSTORMS ARE FROM 18N TO 22N BETWEEN 60W AND
67W. SURFACE RIDGING IS ELSEWHERE ACROSS THE AREA OF DISCUSSION
E OF 60W N OF 18N SUPPORTED BY A BROAD 1022 MB HIGH SW OF THE
AZORES NEAR 35N36W. A LARGE AREA OF AFRICAN DUST FROM THE SAHARA
REGION IS NOTED ON SATELLITE IMAGERY...COVERING MOST OF THE
EASTERN ATLC FROM 14N TO NORTH OF THE AREA OF DISCUSSION BETWEEN
THE COAST OF AFRICA AND 50W. THIS SAHARAN AIR LAYER...ALONG WITH
THE SUB-TROPICAL HIGH ARE KEEPING FAIR WEATHER CONDITIONS IN
THIS REGION.

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

$$

GARCIA




This weather bulletin was brought to you by:
www.nashvilleweather.net