[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 230011
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU NOV 22 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W/51W SOUTH OF 18N
MOVING WEST 10 KT. ALL THE PRECIPITATION FROM 10N TO 20N BETWEEN
40W AND 50W REALLY MOST PROBABLY IS RELATED TO THE DEEP LAYER
CENTRAL ATLANTIC TROUGH AND DISSIPATING COLD FRONT...NOT RELATED
TO THIS TROPICAL WAVE. THIS WAVE WAS MORE READILY APPARENT IN
VISIBLE SATELLITE IMAGERY 24 HOURS AGO...AND NOT AS EASILY
APPARENT IN CURRENT SATELLITE IMAGERY.

A WESTERN CARIBBEAN SEA TROPICAL WAVE ALONG 88W/89W...FROM THE
SOUTHEASTERN YUCATAN PENINSULA TO WESTERN HONDURAS AND EASTERN
EL SALVADOR INTO THE EASTERN PACIFIC OCEAN. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND ISOLATED MODERATE SHOWERS/POSSIBLE
THUNDERSTORMS IN BROAD SURFACE LOW PRESSURE AND SURFACE ONSHORE
FLOW...WEST OF 11N75W 16N80W 22N84W. SHOWERS/THUNDERSTORMS IN
SOUTHERN COSTA RICA PROBABLY ARE RELATED TO THE ITCZ.

...THE ITCZ...
10N14W 6N20W 4N30W 4N43W 2N51W. ISOLATED MODERATE SHOWERS WITHIN
30 TO 60 NM ON EITHER SIDE OF 6N10W 4N20W 5N30W 5N40W...8N50W
8N59W. IT IS EASILY POSSIBLE THAT THE CLOUDS AND POSSIBLE
PRECIPITATION FROM 4N TO 10N BETWEEN 40W AND 50W ARE RELATED
TO THE UPPER LEVEL DIFFLUENT FLOW EAST OF THE CENTRAL ATLANTIC
OCEAN TROUGH.

DISCUSSION...

THE GULF OF MEXICO...
THE 500 MB FLOW IS MOSTLY FROM THE SOUTHWEST OVER THE OPEN GULF
WATERS...AND FROM THE SOUTHWEST TO WEST ACROSS THE U.S.A. GULF
COAST STATES AND IN THE NORTHERN HALF OF TEXAS. THE BASE OF THE
DEEP LAYER TROUGH FROM 24 HOURS AGO ONLY MAKES IT TO OKLAHOMA
AND ARKANSAS. A COLD FRONT STILL CUTS ACROSS THE AREA...FROM
THE FLORIDA PANHANDLE THROUGH 31N85W TO THE CENTRAL GULF OF
MEXICO NEAR 26N90W TO THE MEXICO COAST NEAR 21N98W. THE COLD
FRONT CURVES NORTHWESTWARD OVER INTERIOR MEXICO FROM THE COAST
THROUGH 25N102W TO 30N104W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS ARE NORTHWEST OF 28N83W 24N90W 18N94W. ISOLATED MODERATE
SHOWERS FROM 18N TO 21N BETWEEN 95W AND 103W INLAND...AND FROM
23N TO 24N BETWEEN 93W AND 94W. DISSIPATING CONVECTIVE
PRECIPITATION ELSEWHERE FROM 23N TO 26N BETWEEN 92W AND 95W.
BROKEN LOW TO MIDDLE LEVEL CLOUDS WITHIN 60 NM ON EITHER SIDE
OF 24N88W 26N84W 29N83W WITH A SURFACE TROUGH.

THE CARIBBEAN SEA...
AN UPPER LEVEL RIDGE EXTENDS FROM THE SOUTHWESTERN CORNER OF THE
AREA NORTHWESTWARD...STAYING OVER THE COASTAL WATERS OF CENTRAL
AMERICA FROM PANAMA TO HONDURAS/NICARAGUA...AND THEN CURVING
NORTHWARD TO WESTERN CUBA. MIDDLE TO UPPER LEVEL CYCLONIC FLOW
COVERS THE REST OF THE CARIBBEAN SEA...RELATED TO THE DEEP LAYER
TROUGH THAT STRETCHES FROM THE CENTRAL ATLANTIC OCEAN AND
EVENTUALLY REACHES THE EAST-CENTRAL SECTOR OF THE EASTERN
CARIBBEAN ISLANDS NEAR SAINT LUCIA AND MARTINIQUE. MIDDLE TO
UPPER LEVEL DRY AIR IS NORTH OF 13N60W 15N70W 19N76W. A WESTERN
CARIBBEAN SEA TROPICAL WAVE ALONG 88W/89W...FROM THE SOUTHEASTERN
YUCATAN PENINSULA TO WESTERN HONDURAS AND EASTERN EL SALVADOR
INTO THE EASTERN PACIFIC OCEAN. BROKEN TO OVERCAST MULTILAYERED
CLOUDS AND ISOLATED MODERATE SHOWERS/POSSIBLE THUNDERSTORMS IN
BROAD SURFACE LOW PRESSURE AND SURFACE ONSHORE FLOW...WEST OF
11N75W 16N80W 22N84W. SHOWERS/THUNDERSTORMS IN SOUTHERN COSTA
RICA PROBABLY ARE RELATED TO THE ITCZ.

THE ATLANTIC OCEAN...
A DEEP LAYER CENTRAL ATLANTIC OCEAN TROUGH IS THE MAIN FEATURE.
THE TROUGH PASSES THROUGH 32N51W TO 22N51W TO THE CENTRAL
SECTIONS OF THE EASTERN CARIBBEAN SEA ISLANDS NEAR SAINT LUCIA
AND MARTINIQUE. A DISSIPATING COLD FRONT PASSES THROUGH 32N39W
TO 27N40W TO 19N50W. MIDDLE TO UPPER LEVEL DRY AIR IS 800 NM
WEST/NORTHWEST OF 26N44W 18N50W 12N60W. AN UPPER LEVEL RIDGE
STARTS IN THE NORTHWESTERN CARIBBEAN SEA...NEAR WESTERN CUBA...
CROSSES THE NORTHERN BAHAMAS...AND PASSES BEYOND 32N74W.
AN UPPER LEVEL RIDGE IS EAST OF THE CENTRAL ATLANTIC OCEAN
TROUGH...FROM 8N49W TO 20N41W BEYOND 32N35W. SCATTERED MODERATE
TO STRONG SHOWERS/THUNDERSTORMS FROM 14N TO 17N BETWEEN 43W AND
48W...AND FROM 21N TO 22N BETWEEN 44W AND 45W. OTHER BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND ISOLATED TO WIDELY SCATTERED
MODERATE SHOWERS ARE BETWEEN THE LINE THROUGH 32N29W 20N30W
10N37W AND THE EASTERN EDGE OF THE DRY AIR. A SURFACE RIDGE IS
ALONG THE LINE FROM 1022 MB HIGH PRESSURE NEAR 29N70W TO 19N59W.
BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW IS EAST OF 30W.

$$
MT


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