[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271204
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 27 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURE...

THE CENTER OF HURRICANE KATRINA WAS NEAR 24.4N 84.6W...OR ABOUT
375 NM SE OF THE MOUTH OF THE MISSISSIPPI RIVER...AT 27/1200 UTC
MOVING W 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 940 MB.
MAXIMUM SUSTAINED WIND SPEED IS 100 KT WITH GUSTS TO 120 KT.
PLEASE REFER TO THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER
HEADERS MIATCPAT1/WTNT32 KNHC FOR MORE DETAILS. THE SATELLITE
REPRESENTATION SHOWS A BEAUTIFUL COMMA-SHAPED CLOUD PATTERN
WHICH BEGINS IN THE SOUTHEASTERN GULF OF MEXICO NEAR 25N84W AND
CURVES EASTWARD TO THE FLORIDA KEYS...WITH THE TAIL OF THE COMMA
HOOKING WEST-SOUTHWESTWARD INTO WESTERN CUBA. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS ARE AROUND THE COMMA-SHAPED PART FROM
23N TO 26N BETWEEN 82W AND 86W...AND IN THE BAND WHICH IS ON TOP
OF WESTERN CUBA AND A BIT INTO THE YUCATAN CHANNEL FROM 20.5N TO
23N BETWEEN 82W AND 86W. UPPER LEVEL ANTICYCLONIC OUTFLOW CURVES
OVER FLORIDA AS FAR NORTH AS 29N AND THEN SOUTHEASTWARD TO AT
LEAST EASTERN CUBA...AND EVEN INTO THE NORTHWESTERN CARIBBEAN
SEA AND THE GULF OF HONDURAS/ HONDURAS AND GUATEMALA. UPPER
LEVEL ANTICYCLONIC FLOW COVERS THE U.S.A. GULF COAST STATES IN
THE NORTH CENTRAL GULF OF MEXICO.

...TROPICAL WAVES...

A CENTRAL ATLANTIC WAVE ALONG 38W/39W SOUTH OF 18N NOW MOVING
WEST 10 TO 15 KT. A SURFACE LOW PRESSURE CENTER IS ALONG THIS
WAVE NEAR 11N. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE
FOUND FROM 10N TO 12N BETWEEN 36W AND 39W. LITTLE POCKETS OF
MODERATE SHOWERS AND THUNDERSTORMS COVER THE ATLANTIC WATERS
FROM 10N TO 17N BETWEEN 30W AND 50W.

1009 MB CENTRAL ATLANTIC OCEAN LOW PRESSURE CENTER WAS NEAR
20N51W MOVING NORTHWEST 10 KT. THIS FEATURE HAS BEEN CLASSIFIED
BY THE DVORAK TECHNIQUE AS TOO WEAK TO CLASSIFY FOR THE LAST FEW
DAYS. A TROUGH WAS RUNNING THROUGH THE LOW CENTER ALONG 23N51W
20N51W 16N51W. UPPER LEVEL WINDS REMAIN UNFAVORABLE FOR TROPICAL
CYCLONE FORMATION... AND ADDITIONAL DEVELOPMENT IS UNLIKELY
DURING THE NEXT DAY OR TWO. THE NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS FROM 21N TO 23N BETWEEN 48W AND 51W ARE DETACHED
FROM THE SURFACE LOW PRESSURE CENTER.

WESTERN CARIBBEAN SEA TROPICAL WAVE WAS ALONG 88W SOUTH OF
19N...FROM THE NORTHWESTERN CARIBBEAN SEA SOUTHWARD ACROSS
HONDURAS INTO EL SALVADOR AND EVENTUALLY THE EASTERN PACIFIC
OCEAN...MOVING WEST 15 KT. SCATTERED MODERATE TO STRONG
SHOWERS AND THUNDERSTORMS IN THE EASTERN PACIFIC OCEAN FROM
11N TO 13N BETWEEN 88W AND 91W. THE CLOUD TOPS IN THIS AREA
MAY BE SHEARED BY THE UPPER LEVEL EASTERLY WIND FLOW.

...ITCZ...

ITCZ AXIS IS ALONG 16N17W 14N26W 12N36W...11N41W 14N47W...WEAK
WEST OF 47W. ONE AREA OF NUMEROUS STRONG THUNDERSTORMS REMAINS
FROM THE LARGER AREA OF SIX HOURS AGO...NOW UP AGAINST THE
GUINEA COAST WEST OF SIERRA LEONE FROM 8N TO 10N BETWEEN 13W AND
15W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ALSO ARE FOUND
FROM 10N TO 12N BETWEEN 36W AND 39W. ISOLATED MODERATE SHOWERS
ELSEWHERE FROM THE EQUATOR TO 10N BETWEEN 30W AND 49W.

...DISCUSSION...

THE GULF OF MEXICO...
HURRICANE KATRINA IS GRABBING ALL THE HEADLINES AT THIS MOMENT.
THE CIRCULATION OF KATRINA DOMINATES THE ENTIRE GULF AS
NORTHEASTERLY SURFACE WINDS ARE OBSERVED PRACTICALLY EVERYWHERE
WEST OF THE LONGITUDE FOR KATRINA. NUMEROUS STRONG CONVECTIVE
ACTIVITY IS CONFINED TO THE SOUTHEASTERN CORNER OF THE AREA
SOUTH OF 26N EAST OF 87W. ISOLATED MODERATE SHOWERS ARE
OCCURRING JUST OFFSHORE THE NORTHERN YUCATAN PENINSULA COAST AT
THE TAIL END OF THE PRECIPITATION WHICH STARTS IN WESTERN CUBA
AND WHICH MAKES ITS WAY ACROSS THE YUCATAN CHANNEL. UPPER LEVEL
ANTICYCLONIC FLOW COVERS THE U.S.A. GULF COAST STATES IN THE
NORTH CENTRAL GULF OF MEXICO. MOISTURE FROM KATRINA SHOULD
SPREAD ACROSS THE GULF COAST ON SATURDAY FROM EAST TO WEST...
IMPACTING SOUTHEASTERN LOUISIANA BY SUNDAY.

THE CARIBBEAN SEA...
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS IN WESTERN CUBA FROM
THE RAIN BAND TO THE SOUTH OF HURRICANE KATRINA. LARGE-SCALE
UPPER HIGH PRESSURE CONTROLS THE REGION WITH GENERAL NE TO E
WINDS THROUGHOUT THE CARIBBEAN. A MIDDLE TO UPPER LEVEL TROUGH
RUNS FROM THE ATLANTIC OCEAN NEAR 31N63W...ACROSS PUERTO RICO...
INTO THE EAST CENTRAL CARIBBEAN SEA. ISOLATED TO WIDELY
SCATTERED  MODERATE SHOWERS AND THUNDERSTORMS EXTEND FROM THE
EAST CENTRAL CARIBBEAN SEA NORTHWARD TO 20N BETWEEN 64W AND 70W.

THE ATLANTIC OCEAN...
UPPER LEVEL ANTICYCLONIC FLOW WITH A RIDGE...SEPARATE FROM THE
ONE ON TOP OF HURRICANE KATRINA...EXTENDS FROM THE SOUTHEASTERN
U.S.A. CURVING INTO THE ATLANTIC OCEAN SOUTHEASTWARD AS IT
COMBINES WITH THE FLOW FROM THE MIDDLE TO UPPER LEVEL 31N63W-
TO-EAST CENTRAL CARIBBEAN SEA TROUGH. A SURFACE STATIONARY FRONT
PASSES THROUGH 33N60W TO 32N70W TO 33N78W. WIDELY SCATTERED
MODERATE SHOWERS AND THUNDERSTORMS ARE FOUND FROM 26N TO 33N
BETWEEN 69W AND 80W. A COUPLE OF LARGE-SCALE MODELS ARE
SHOWING THE POTENTIAL FOR A SURFACE LOW PRESSURE CENTER TO
GENERATE NEAR THE FRONT AND MOVE SLOWLY EASTWARD...PERHAPS
ACQUIRING SOME TROPICAL CHARACTERISTICS WITH TIME. THIS GENESIS
SEEMS LIKE IT WOULD BE SLOW TO OCCUR WITH STRONG SHEAR FORECAST.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS ARE IN THE AREA OF THE CYCLONIC FLOW OF THE TROUGH
FROM 21N TO 32N BETWEEN 48W AND 70W. UPPER LEVEL ANTICYCLONIC
FLOW WITH A RIDGE IS SURROUNDED BY MIDDLE TO UPPER LEVEL DRY
AIR...NORTH OF 29N BETWEEN 32W AND 48W. MIDDLE TO UPPER LEVEL
CYCLONIC CIRCULATION CENTER IS NEAR 33N22W WITH NO SURFACE
REFLECTION. MIDDLE TO UPPER LEVEL CYCLONIC FLOW COVERS THE
ATLANTIC WATERS NORTH OF 27N BETWEEN 10W AND 32W. SURFACE HIGH
PRESSURE AND ANTICYCLONIC WIND FLOW COVER THE ATLANTIC WATERS
NORTH OF 23N BETWEEN AFRICA AND 50W.

$$
MT


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