[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 250019 RRA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED AUG 24 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 1800 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 2315 UTC.

...SPECIAL FEATURES...
THE CENTER OF TROPICAL STORM KATRINA IS LOCATED NEAR LATITUDE
26.0 NORTH...LONGITUDE 77.6 WEST OR ABOUT 65 MILES...105
KM...NORTH OF NASSAU AND ABOUT 165 MILES... 270 KM...EAST OF THE
SOUTHEAST COAST OF FLORIDA.  IT IS MOVING NORTHWEST 8 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. THE MAXIMUM
SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER HEADERS
MIATCPAT1/WTNT32 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS OVER THE BAHAMAS FROM 23N-28N
BETWEEN 73W-80W.  A FEEDER BAND IS OVER CUBA FROM 21N-23N
BETWEEN 78W-85W.

AN ATLANTIC 1009 MB LOW PRESSURE CENTER IS NEAR 17N42W MOVING
WEST ABOUT 10 KT. IT IS POSSIBLE THAT THIS FEATURE MAY BECOME A
TROPICAL CYCLONE DURING THE NEXT 24 HOURS. THE LOW IS ON A
TROPICAL WAVE AXIS ALONG 42W.  THE LOW HAS CONSIDERABLE UPPER
LEVEL SHEAR PRODUCING CONVECTION WELL E OF THE CENTER.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 17N-20N
BETWEEN 38W-41W.

...TROPICAL WAVES...
ATLANTIC OCEAN TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS
ALONG 27W SOUTH OF 16N MOVING WEST 10-15 KT. WEAK CYCLONIC FLOW
APPEARS TO BE PRESENT IN THE LOW TO MID LEVEL CLOUD FIELD.
CONVECTION IS CONFINED TO THE ITCZ.

CARIBBEAN SEA TROPICAL WAVE IS ALONG 72W S OF 21N MOVING WEST
15-20 KT.  THIS WAVE IS PRODUCING CONVECTION OVER PUERTO
RICO...HISPANIOLA...AND JAMAICA.  SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS FROM 16N-20N BETWEEN 65W-78W.

SOUTHWESTERN GULF OF MEXICO TROPICAL WAVE IS ALONG 94W SOUTH OF
21N MOVING WEST 10 KT.  CONVECTION IS INLAND OVER S MEXICO FROM
14N-18N BETWEEN 91W-97W.

...THE ITCZ...
ITCZ IS CENTERED ALONG 14N17W 7N27W 16N42W 10N50W 10N63W.
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER
W AFRICA FROM 7N-14N BETWEEN 8W-15W.  WIDELY SCATTERED MODERATE
CONVECTION IS FROM 10N-14N BETWEEN 39W-44W.  ISOLATED MODERATE
CONVECTION IS FROM 6N-9N BETWEEN 44W-47W...AND FROM 14N-17N
BETWEEN 54W-57W.

...DISCUSSION...
THE GULF OF MEXICO...
A WEAK SURFACE PRESSURE GRADIENT IS OVER THE GULF OF MEXICO
PRODUCING LIGHT WINDS MOSTLY FROM THE NE.  ALL THIS IS IN
ADVANCE OF THE ARRIVAL OF TROPICAL STORM KATRINA...STILL OVER
THE BAHAMAS ISLANDS MOVING NW AT 8KT.  THE NORTHERN PORTION OF A
TROPICAL WAVE IS ALSO OVER THE BAY OF CAMPECHE PRODUCING
CONVECTION INLAND OVER S MEXICO.  SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS ALONG THE W COAST OF FLORIDA FROM 25N-30N
BETWEEN 82W-84W.  ISOLATED MODERATE CONVECTION IS OVER THE N
GULF COAST BETWEEN LOUISIANA AND THE FLORIDA PANHANDLE FROM
29N-31N BETWEEN 86W-92W.  IN THE UPPER LEVELS... A SMALL
CYCLONIC CIRCULATION IS OVER THE FLORIDA KEYS NEAR 24N83W.  THIS
SYSTEM IS PRODUCING SOME UPPER LEVEL SHEAR TO THE W SIDE OF
TROPICAL STORM KATRINA...BUT IS MOVING W AND MAY DISTANCE ITSELF
FROM KATRINA...AND ALLOW FOR SLOW INTENSIFICATION OF THE STORM.
A STRONG ANTICYCLONIC CIRCULATION IS CENTERED OVER S LOUISIANA
NEAR 31N90W.  ANTICYCLONIC FLOW IS W OF 87W AND N OF 23N.
ANOTHER SMALL CYCLONIC CIRCULATION IS OVER THE BAY OF CAMPECHE
NEAR 21N96W PRODUCING CYCLONIC FLOW S OF 23N AND W OF 90W.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN SEA. SEE ABOVE.
WESTERN CUBA ALSO HAS CONVECTION DUE TO A T.S. KATRINA FEEDER
BAND...SEE ABOVE.  A 1008 MB LOW IS OVER N COLOMBIA NEAR
11N72W.  SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
FROM 10N-12N BETWEEN 74W-76W.  SIMILAR CONVECTION IS ALONG THE
COAST OF PANAMA FROM 7N-12N BETWEEN 78W-84W.  CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER
CENTRAL AMERICA FROM NICARAGUA TO THE YUCATAN PENINSULA N OF
11N.  IN THE UPPER LEVELS...A CYCLONIC CIRCULATION IS CENTERED
OVER NICARAGUA NEAR 12N86W ENHANCING CONVECTION OVER NICARAGUA
AND HONDURAS.  MOSTLY EASTERLY UPPER LEVEL WINDS COVERS THE
REMAINDER OF THE CARIBBEAN SEA.  EXPECT CUBA TO HAVE LIGHT
WESTERLY SURFACE WINDS AND CONVECTION DUE TO T.S. KATRINA DURING
THE NEXT 24 HOURS.  ALSO EXPECT THE REMAINDER OF THE CARIBBEAN
TO HAVE EASTERLY TRADEWINDS WITH CONVECTION FROM THE TROPICAL
WAVE MOVING W.

THE ATLANTIC OCEAN...
BESIDES T.S. KATRINA THE SUBTROPICAL ATLANTIC HAS EASTERLY
SURFACE WINDS DUE TO A LARGE 1031 MB HIGH CENTERED W OF THE
AZORES NEAR 40N36W.  IN THE UPPER LEVELS... A CYCLONIC
CIRCULATION IS OVER THE W ATLANTIC NEAR 27N61W.  CYCLONIC FLOW
IS N OF 23N BETWEEN 55W-70W.  ANOTHER CYCLONIC CIRCULATION IS
OVER THE CENTRAL ATLANTIC NEAR 19N43W.  THIS CIRCULATION IS
PRODUCING UPPER LEVEL SHEAR OVER THE W SIDE OF THE SURFACE LOW
AT 17N42W.  AN ANTICYCLONIC CIRCULATION IS OVER W AFRICA NEAR
20N15W.

$$
FORMOSA


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