[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251817
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON 25 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 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1745 UTC.

...SPECIAL FEATURE...
A LARGE 993 MB EXTRATROPICAL LOW PRESSURE CENTER NEAR 33N57W...
ABOUT 500 MILES EAST-NORTHEAST OF BERMUDA...MOVING
EAST-NORTHEAST 20 MPH. THIS SYSTEM IS BEING MONITORED FOR
SIGNS OF POSSIBLE SUBTROPICAL CYCLONE FORMATION. ADDITIONAL
INFORMATION CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY
THE OCEAN PREDICTION CENTER...UNDER AWIPS HEADER NFDHSFAT1
AND WMO HEADER FZNT01 KWBC. SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS FROM 34N TO 35N BETWEEN 66W
AND 69W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
ELSEWHERE FROM 30N TO 36N BETWEEN 60W AND 70W.

...TROPICAL WAVES...
TROPICAL WAVE 59W/61W SOUTH OF 15N MOVING WEST 10 TO 15 KT.
THIS WAVE IS APPARENT IN VISIBLE SATELLITE IMAGERY. SCATTERED
MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 13N
BETWEEN 59W AND 63W. ISOLATED MODERATE SHOWERS ELSEWHERE FROM
7N TO 13N BETWEEN 54W AND 60W...INCLUDING POSSIBLE PRECIPITATION
WITH THE ITCZ.

...ITCZ...
ITCZ 10N13W 9N30W 7N40W 7N50W 8N59W 11N62W 9N74W 11N86W.
SCATTERED TO NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM
6N TO 10N BETWEEN 20W AND 27W...AND FROM 11N TO 13N BETWEEN
26W AND 30W. ISOLATED MODERATE SHOWERS FROM 6N TO 10N BETWEEN
77W AND 86W.

...DISCUSSION...

THE GULF OF MEXICO...
MIDDLE TO UPPER LEVEL DRY AIR AND BROAD ANTICYCLONIC FLOW
EVERYWHERE IN THE GULF. MIDDLE TO UPPER LEVEL CYCLONIC
CIRCULATION CENTER NEAR 15N94W IN THE GULF OF TEHUANTEPEC
ON THE EASTERN PACIFIC OCEAN SIDE OF MEXICO. CYCLONIC FLOW
FROM THIS CIRCULATION FROM 12N TO 20N BETWEEN 91W AND 99W.
WEAK SURFACE PRESSURE GRADIENT IN THE GULF OF MEXICO.
1018 MB HIGH PRESSURE CENTER IN NORTHEAST FLORIDA NEAR 29N82W.

THE CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL DRY AIR EVERYWHERE EXCEPT FOR THE
SOUTHEASTERN CORNER...SOUTH OF 14N EAST OF 67W...AND IN
THE SHOWERS WITHIN 25 TO 40 NM ON EITHER SIDE OF 18N60W
16N64W...WITH THE 17N59W 14N66W SURFACE TROUGH. THE DRY AIR
IS COMPARATIVELY DRIER NORTH AND NORTHWEST OF 20N60W 18N70W
16N80W 16N85W. UPPER LEVEL RIDGE FROM THE ATLANTIC OCEAN NEAR
32N32W TO 23N42W TO 15N52W INTO THE CARIBBEAN SEA NEAR 13N66W.
SOME OF THE UPPER LEVEL ANTICYCLONIC FLOW FROM THE GULF OF
MEXICO IS IN THE NORTHWESTERN CORNER OF THE AREA. MIDDLE TO
UPPER LEVEL EASTERLY FLOW ELSEWHERE. WEAK SURFACE PRESSURE
GRADIENT IN THE CARIBBEAN SEA.

THE SUBTROPICAL ATLANTIC OCEAN...
CYCLONIC FLOW FROM DEEP LAYER TROUGH NORTH OF 20N BETWEEN
32N43W 20N58W AND 80W. THE MIDDLE TO UPPER LEVEL TROUGH RUNS
FROM THE CYCLONIC CIRCULATION CENTER NEAR 31N67W TO 22N70W
TO 20N74W. MIDDLE TO UPPER LEVEL DRY AIR NORTH AND NORTHWEST
OF 30N44W 24N50W 20N60W. DISSIPATING SURFACE COLD FRONT 31N43W
24N50W 17N59W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND WIDELY
SCATTERED MODERATE TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS
WITHIN 120 TO 180 NM ON EITHER SIDE OF 20N51W 25N44W BEYOND
32N38W...AND WITHIN 15 NM ON EITHER SIDE OF 21N53W 19N57W.
SURFACE RIDGE 15N51W 16N44W 19N39W 23N35W TO 1021 MB HIGH
PRESSURE CENTER NEAR 33N18W AT THE WESTERN EDGE OF THE MADEIRA
ISLANDS. UPPER LEVEL RIDGE FROM THE ATLANTIC OCEAN NEAR 32N32W
TO 23N42W TO 15N52W INTO THE CARIBBEAN SEA NEAR 13N66W. A MIDDLE
TO UPPER LEVEL TROUGH HAS DUG INTO NORTHERN MOROCCO. BROAD
MIDDLE TO UPPER LEVEL CYCLONIC FLOW FROM 10N TO 28N BETWEEN
AFRICA COAST AND 40W. A CYCLONIC CENTER APPEARS TO BE NEAR
18N27W. A SHIELD OF OVERCAST HIGH CLOUDS IS MOVING NORTHWARD
ACROSS THE CAPE VERDE ISLANDS...BLOCKING SOME OF THE CHANCE
TO SEE BETTER THE CYCLONIC CENTER. MIDDLE TO UPPER LEVEL DRY
AIR FROM 10N TO 24N BETWEEN 27W AND 40W...AND FROM 27N TO 30N
BETWEEN THE AFRICA COAST AND 30W.

THE TROPICAL ATLANTIC OCEAN...
UPPER LEVEL ANTICYCLONIC FLOW WEST OF 40W...WITH THE ATLANTIC-
TO CARIBBEAN SEA 32N32W 23N42W 15N52W 13N66W RIDGE. A CYCLONIC
CENTER APPEARS TO BE NEAR 18N27W. A SHIELD OF OVERCAST HIGH
CLOUDS IS MOVING NORTHWARD ACROSS THE CAPE VERDE ISLANDS...
BLOCKING SOME OF THE CHANCE TO SEE BETTER THE CYCLONIC CENTER.
MIDDLE TO UPPER LEVEL DRY AIR FROM 10N TO 24N BETWEEN 27W AND
40W...AND FROM 27N TO 30N BETWEEN THE AFRICA COAST AND 30W.
UPPER LEVEL ANTICYCLONIC FLOW IN THE TROPICS IS LIMITED
TO AFRICA.

$$
MT


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