[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT SEP 15 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...SPECIAL FEATURES...

HURRICANE NADINE IS CENTERED NEAR 30.0N 52.8W 15/0300 UTC OR
ABOUT ABOUT 630 NM E OF BERMUDA...AND ABOUT 1365 NM WSW OF THE
AZORES. NADINE IS MOVING NNE AT 12 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 985 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH
GUSTS TO 80 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. NUMEROUS STRONG
CONVECTION IS FROM 30N-32N BETWEEN 52W-55W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 27N-35N
BETWEEN 48W-56W.

...TROPICAL WAVES...

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ALONG 15N51W TO 9N46W MOVING W NEAR 15 KT. THE WAVE LIES WITHIN
AN AREA OF MAXIMUM MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER
IMAGERY. A RECENT ASCAT SCATTEROMETER PASS ALSO INDICATES THAT
LOW-LEVEL CYCLONIC FLOW IS PRESENT AROUND THE WAVE AXIS.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-16N
BETWEEN 46W-53W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
GUINEA-BISSAU AT 12N16W CONTINUING OVER ATLC WATERS ALONG 8N22W
8N31W. THE ITCZ EXTENDS FROM 8N31W TO 11N40W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 8N-11N BETWEEN 23W-26W.
ISOLATED MODERATE CONVECTION IS FROM 8N-9N BETWEEN 28W-32W.
SIMILAR ACTIVITY IS FROM 9N-11N BETWEEN 35W-37W.

...DISCUSSION...

GULF OF MEXICO...
SHOWERS/THUNDERSTORMS ACROSS THE GULF OF MEXICO HAVE DIED DOWN
SOME FROM EARLIER IN THE EVENING. RADAR IMAGERY CONTINUES TO
SHOW A FEW SHOWERS/THUNDERSTORMS ALONG THE TEXAS COAST
ASSOCIATED WITH A STATIONARY FRONT THAT PARALLELS THE COASTLINE.
SOME ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO OVER THE EASTERN
GULF AND PORTIONS OF FLORIDA ASSOCIATED WITH BROAD SURFACE
TROUGHING AROUND AN AXIS FROM 25N90W TO 22N85W...AS OF 0300 UTC.
SOME OF THIS ACTIVITY IS ALSO SUPPORTED BY DIFFLUENCE ALOFT
AROUND AN UPPER LEVEL TROUGH EXTENDING FROM NE FLORIDA TO THE SW
GULF. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO PRESENT IN THE
CENTRAL GULF FROM 24N-26N BETWEEN 89W-93W...AND IN THE SW GULF
FROM 20N-23N BETWEEN 94W-97W. THIS ACTIVITY IS LIKELY TIED TO
THE UPPER TROUGH AS WELL. MOIST CONDITIONS ARE EXPECTED TO
REMAIN ACROSS THE BASIN FOR AT LEAST THE NEXT 24 HOURS AS THE
UPPER TROUGH REMAINS OVER THE BASIN.

CARIBBEAN SEA...
THE CARIBBEAN IS MOSTLY CALM TONIGHT WITH CLEAR SKIES COVERING
THE MAJORITY OF THE AREA. THIS FAIR WEATHER IS RELATED TO DRY
AIR ALOFT AROUND AN UPPER LEVEL RIDGE COVERING THE ENTIRE
CENTRAL AND WESTERN CARIBBEAN. A FEW SHOWERS/THUNDERSTORMS
CONTINUE ACROSS CENTRAL CUBA AND OVER NORTHERN NICARAGUA...BUT
ALL OTHER ACTIVITY HAS NOW DIED DOWN. A VERY NARROW UPPER TROUGH
IS OVER THE EASTERN CARIBBEAN EXTENDING FROM PUERTO RICO TO
VENEZUELA...BUT IT IS EMBEDDED WITH DRY AIR PREVENTING IT FROM
CAUSING ANY ACTIVE WEATHER AT THIS TIME. TRADEWIND FLOW OF 10-15
KT IS PRESENT ACROSS THE AREA WITH SOME STRONGER WINDS NORTH OF
COLOMBIA. EXPECT SHOWERS/THUNDERSTORMS ACROSS THE SW CARIBBEAN
AND CENTRAL AMERICA DURING THE DAYTIME HOURS WITH LITTLE CHANGE
ELSEWHERE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE SW NORTH
ATLANTIC TONIGHT PROVIDING MOSTLY FAIR CONDITIONS BESIDES A FEW
ISOLATED SHOWERS OFF THE EAST COAST OF FLORIDA. A NARROW UPPER
LEVEL TROUGH EXTENDS FROM 30N63W TO PUERTO RICO SUPPORTING A
WEAK SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL
BOUNDARY...ALONG 31N68W TO 24N72W. POSSIBLE ISOLATED SHOWERS ARE
WITHIN 60 NM OF THE AXIS. TO THE E...HURRICANE NADINE DOMINATES
THE CENTRAL ATLC. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A
WEAK SURFACE HIGH IS E OF NADINE CENTERED NEAR 28N44W. THE RIDGE
IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED SOUTH OF NADINE
NEAR 22N49W. THE UPPER RIDGE ALONG WITH THE SURFACE RIDGE ARE
PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC. AN UPPER LEVEL TROUGH COVERS THE EASTERN ATLC
EXTENDING FROM THE AZORES ISLANDS TO NEAR 24N24W 20N38W...BUT IS
NOT CAUSING ANY ACTIVE WEATHER IN THE DISCUSSION AREA. VISIBLE
SATELLITE IMAGERY FROM EARLIER IN THE DAY ALONG WITH GOES-R
ENHANCED IMAGERY INDICATE THAT AN AREA OF SAHARAN DUST EXTENDS S
OF 20N FROM THE COAST OF AFRICA TO NEAR 40W.

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

$$
WALTON





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