[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210623
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU 21 OCT 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLC 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 0545 UTC.

...TROPICAL WAVES...
CENTRAL ATLANTIC TROPICAL WAVE 53W/54W SOUTH OF 20N MOVING WEST
10 KT. WAVE IS MOVING UNDER THE AREA OF A MIDDLE TO UPPER LEVEL
CYCLONIC CIRCULATION CENTER NEAR 16N55W. ISOLATED MODERATE TO
LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 16N TO 20N BETWEEN
50W AND 60W. UPPER-LEVEL WINDS ARE NOT FAVORABLE FOR TROPICAL
CYCLONE FORMATION.

WESTERN CARIBBEAN SEA TROPICAL WAVE 76W/77W SOUTH OF 20N MOVING
WEST 10 KT. THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH REACHES
TO 15N80W IN THE WEST CENTRAL CARIBBEAN SEA AS THE WAVE MOVES
TOWARD THAT SPOT. THERE IS NOT ANY ONE AREA OF SHOWERS AND/OR
THUNDERSTORMS WHICH IS DIRECTLY ATTRIBUTABLE TO THIS WAVE.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM
5N TO 9N BETWEEN 74W AND 76W IN COLOMBIA...AND FROM 6N TO 8N
BETWEEN 78W AND 79W IN THE EASTERN PACIFIC OCEAN...PROBABLY
MORE RELATED TO THE ITCZ THAN ANYTHING ELSE.

...ITCZ...
ITCZ 10N13W 8N20W 10N38W 12N47W 12N52W 12N55W 11N70W 10N75W
10N78W 9N85W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG
SHOWERS AND THUNDERSTORMS FROM 4N TO 10N BETWEEN 27W AND 40W.
WIDELY SCATTERED TO SCATTERED MODERATE/ISOLATED STRONG SHOWERS
AND THUNDERSTORMS FROM 10N TO 20N BETWEEN 35W AND 50W...UNDER
AN UPPER LEVEL RIDGE AND TO THE EAST OF AN AREA OF UPPER LEVEL
DIFFLUENT FLOW.

...DISCUSSION...
THE GULF OF MEXICO...
BROAD UPPER LEVEL ANTICYCLONIC FLOW FROM A RIDGE IN CENTRAL
MEXICO COVERS THE AREA NORTH OF 13N BETWEEN 87W AND 110W.
MIDDLE TO UPPER LEVEL DRY AIR COVERS THIS SAME AREA...WITH
NO DEEP THUNDERSTORMS. A MIDDLE TO UPPER LEVEL TROUGH HAS BEEN
MOVING THROUGH FLORIDA DURING THE LAST 12 HOURS OR SO...WITH
THE BASE NOW NEAR 80W IN THE STRAITS OF FLORIDA. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS ARE ON
THE EASTERN SIDE OF THE TROUGH...NORTH OF 23N BETWEEN 73W AND
79W. 1016 MB SURFACE HIGH PRESSURE CENTER NEAR 27N88W. WEAK
SURFACE PRESSURE GRADIENT IN THE GULF OF MEXICO.

THE CARIBBEAN SEA...
UPPER LEVEL ANTICYCLONIC FLOW FROM THE MEXICO RIDGE COVERS THE
AREA WEST OF 80W. THE BASE OF AN ATLANTIC OCEAN-TO-WESTERN
CARIBBEAN SEA TROUGH REACHES 15N80W...FROM 27N67W IN THE
ATLANTIC WATERS. MIDDLE TO UPPER LEVEL DRY AIR IS WEST AND
NORTHWEST OF 19N69W 15N76W 12N84W...MIDDLE TO UPPER LEVEL
MOISTURE IS EAST OF THIS SAME LINE UNDER UPPER LEVEL
SOUTHWESTERLY FLOW.

THE SUBTROPICAL ATLANTIC...
THE MOIST MIDDLE TO UPPER LEVEL SOUTHWESTERLY FLOW FROM THE
CARIBBEAN SEA IS BEING TRANSPORTED TO THE NORTHEAST...INTO THE
ATLANTIC OCEAN TO 27N58W...AND THEN PUSHED EASTWARD BY THE UPPER
LEVEL WESTERLIES. SURFACE RIDGE 25N73W 27N65W TO 1020 MB HIGH
PRESSURE CENTER NEAR 32N48W. UPPER LEVEL WESTERLIES EVERYWHERE
IN THE REST OF THE SUBTROPICAL ATLANTIC OCEAN EAST OF 50W.
THE MIDDLE TO UPPER LEVEL FLOW IS MUCH MORE CYCLONIC NORTH OF
30N EAST OF 30W DUE TO A TROUGH SWEEPING TOWARD WESTERN EUROPE
AND NORTHWESTERN AFRICA.

THE TROPICAL ATLANTIC...
THE 53W/54W TROPICAL WAVE IS MOVING UNDER THE AREA OF A MIDDLE
TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 16N55W. ISOLATED
MODERATE TO LOCALLY STRONG SHOWERS AND THUNDERSTORMS FROM 16N TO
20N BETWEEN 50W AND 60W. UPPER-LEVEL WINDS ARE NOT FAVORABLE FOR
TROPICAL CYCLONE FORMATION. UPPER LEVEL ANTICYCLONIC FLOW IN THE
REST OF THE TROPICAL ATLANTIC EAST OF 50W.

$$
MT


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