[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 08 2008

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...
NONE.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W SOUTH OF 13N
MOVING WEST 10 KT TO 15 KT. ANY PRECIPITATION ANYWHERE CLOSE
TO THIS WAVE IS MIXED WITH ITCZ CLOUDS AND PRECIPITATION.

AN ATLANTIC OCEAN TROPICAL WAVE WAS PUT ON THE MAP AT
08/0000 UTC ALONG 36W/37W. WHAT WE ARE CALLING A TROPICAL
WAVE NOW STILL APPEARS TO BE ALONG 37W OR SO WITHOUT HAVING
MOVED MUCH OR ANY DURING THE LAST 12 HOURS. A SURFACE TROUGH
WAS INCLUDED IN THE MAP ANALYSIS 24 HOURS AGO ROUGHLY ALONG
36W/37W. A SEPARATE AND INDEPENDENT SMALL SURFACE 1012 MB
LOW PRESSURE CENTER IS NEAR 14N34W. STRONG SHOWERS AND
THUNDERSTORMS ARE WITHIN A 15 NM RADIUS OF 15N33.5W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 55W SOUTH OF 16N
MOVING WEST 10 TO 15 KT. WEAK CYCLONIC SWIRLS ARE ALONG THIS
WAVE. ONE WEAK CYCLONIC SWIRL IN VISIBLE IMAGERY APPEARS NEAR
17N58W. THE COMBINATION OF THE MIDDLE TO UPPER LEVEL CYCLONIC
FLOW AROUND A 21N38W CYCLONIC CIRCULATION CENTER...A DEEP LAYER
TROUGH FROM THE NORTHWEST...AND UPPER LEVEL ANTICYCLONIC FLOW
ON TOP OF NORTHEASTERN SOUTH AMERICA PUTS CONVECTIVE
PRECIPITATION IN THE AREA CLOSE TO THE 55W TROPICAL WAVE.
MY FIRST GUESS IS THAT MOST OF THE PRECIPITATION IS RELATED
TO THE MIDDLE TO UPPER LEVEL FEATURES...AND NOT RELATED
TO THE TROPICAL WAVE AS MUCH.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 74W SOUTH OF 18N AND
SOUTH OF SOUTHWESTERN HAITI. THIS WAVE IS MOVING TOWARD THE AREA
OF AN UPPER LEVEL RIDGE THAT RUNS FROM NORTHWESTERN COLOMBIA
TO 20N80W. SHOWERS AND THUNDERSTORMS ARE IN NEAR THIS WAVE...
BUT THEY MAY BE MORE RELATED TO THE DIFFLUENT FLOW RELEVANT
TO THE PREVAILING MIDDLE TO UPPER LEVEL WEATHER PATTERN.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 83W SOUTH OF 20N MOVING
WEST 10 TO 15 KT. THIS WAVE IS MOVING THROUGH THE EASTERN PART
OF THE MIDDLE TO UPPER LEVEL FLOW THAT IS MOVING AROUND
A 16N86W WESTERN CARIBBEAN SEA CYCLONIC CIRCULATION CENTER.
UPPER LEVEL DIFFLUENT FLOW IS IN THE COASTAL WATERS FROM COSTA
RICA TO EASTERN HONDURAS. SCATTERED MODERATE SHOWERS TO ISOLATED
STRONG THUNDERSTORMS ARE IN THE AREA OF THIS DIFFLUENT FLOW.

...THE ITCZ...
6N12W 7N36W 9N53W 10N61W. WIDELY SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS ARE FROM 2N TO 11N BETWEEN
10W AND 47W...AND SOUTH OF 11N BETWEEN 52W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...AND THE ATLANTIC OCEAN WEST OF 50W
WITH A COLD FRONT...
A DEEP LAYER TROUGH IN THE WESTERN ATLANTIC OCEAN IS DRIVING
AN ATLANTIC OCEAN COLD FRONT THROUGH 32N51W 27N60W 25N70W
28N80W...BECOMING A DEVELOPING WARM FRONT CROSSING FLORIDA
BEYOND 31N86W IN THE FLORIDA PANHANDLE. ISOLATED MODERATE
SHOWERS ARE WITHIN 30 NM ON EITHER SIDE OF THE FRONT IN THE
ATLANTIC OCEAN...AND IN THE FLORIDA PANHANDLE. A DEEP LAYER
TROUGH MOVING THROUGH THE U.S.A. JUST TO THE EAST OF THE
MISSISSIPPI RIVER IS PUSHING A COLD FRONT AND A PRE-FRONTAL
TROUGH THAT PASS THROUGH SOUTHERN MISSISSIPPI AND SOUTHEASTERN
LOUISIANA INTO THE NORTH CENTRAL GULF OF MEXICO...TO THE MEXICO
COAST NEAR 24N91W. ISOLATED MODERATE SHOWERS ARE WITHIN 60 NM ON
EITHER SIDE OF 30N86W 28N87W 24N94W. WIDELY SCATTERED MODERATE
SHOWERS ARE FROM 19N TO 24N BETWEEN 96W AND THE MEXICO COAST.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL 16N86W CYCLONIC CIRCULATION CENTER IS
SPREADING CYCLONIC FLOW FROM PANAMA AND NICARAGUA TO THE YUCATAN
CHANNEL. MIDDLE TO  UPPER LEVEL CYCLONIC FLOW CUTS INTO THE
NORTHEASTERN AND EASTERN CARIBBEAN SEA FROM AN ATLANTIC OCEAN
FROM A 24N57W 18N62W TROUGH. DRY AIR IS NORTH OF 18.5N TO THE
FROM HISPANIOLA EASTWARD TO 62W. STRONG SHOWERS AND
THUNDERSTORMS IN CLUSTERS ARE FROM 11N TO 16N BETWEEN 62W AND
72W IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW. UPPER LEVEL
ANTICYCLONIC FLOW THAT COVERS COLOMBIA AND VENEZUELA.

THE REST OF THE ATLANTIC OCEAN...
THE 22N62W MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER
FROM 24 HOURS AGO HAS DISSIPATED. A TROUGH REMAINS ALONG 24N57W
18N62W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE ON THE EASTERN SIDE OF THE TROUGH...FROM 18N
TO 22N BETWEEN 52W AND 56W.

A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
21N38W. CYCLONIC FLOW AROUND THIS CENTER COVERS THE AREA FROM
12N TO 33N BETWEEN 30W AND 55W. STRONG SHOWERS AND THUNDERSTORMS
ARE WITHIN 30 NM TO 60 NM ON EITHER SIDE OF BEYOND 26N53W 29N51W
32N48W.

$$
MT



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