000
AXNT20 KNHC 211759
TWDAT 

TROPICAL WEATHER DISCUSSION       
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 21 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 
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...WEATHER OBSERVATIONS...RADAR... 
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W/44W SOUTH OF 22N 
MOVING WEST 10 TO 15 KT. SCATTERED MODERATE SHOWERS TO ISOLATED 
STRONG THUNDERSTORMS FROM 6N TO 12N BETWEEN 33W AND 40W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 56W/57W SOUTH OF 17N 
MOVING WEST 10 TO 15 KT. THIS WAVE IS NOT READILY APPARENT IN 
VISIBLE SATELLITE IMAGERY AT THIS THIS MOMENT. 

...THE ITCZ...
8N12W 6N20W 6N30W 6N42W 6N45W 6N55W. WIDELY SCATTERED TO 
SCATTERED MODERATE SHOWERS/ISOLATED STRONG THUNDERSTORMS
FROM 2N TO 10N BETWEEN 16W AND 30W...AND FROM 3N TO 6N
BETWEEN 30W AND 35W. ISOLATED MODERATE SHOWERS ELSEWHERE
FROM 2N TO 10N BETWEEN 40W AND 55W.

...DISCUSSION...
THE GULF OF MEXICO...
UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA. A RIDGE RUNS
FROM THE SOUTHWESTERN COAST OF FLORIDA TO THE MEXICO GULF COAST 
NEAR 22N98W. MIDDLE TO UPPER LEVEL DRY AIR COVERS MOST OF THE 
AREA EXCEPT FOR CLOUDS AND PRECIPITATION IN THE NORTH CENTRAL 
GULF WATERS AND COASTAL PLAINS. A COLD FRONT GOES FROM AN
ATLANTIC OCEAN 1012 MB LOW PRESSURE CENTER NEAR 32N77W TO 
INTERIOR FLORIDA NEAR 28N82W TO 28N85W. A WARM FRONT CONTINUES
FROM 28N85W TO 28N90W TO 28N95W TO THE TEXAS GULF COAST NEAR 
27N98W. ISOLATED SHOWERS ARE IN THE ATLANTIC OCEAN FROM 30N
TO 32N BETWEEN 75W AND 78W...AND IN THE GULF OF MEXICO WITHIN 
30 TO 45 NM ON EITHER SIDE OF 28N84W 28N87W 28N90W 30N95W
IN TEXAS.

FROM THE BAHAMAS AND PARTS OF THE ATLANTIC OCEAN NORTH
OF THE NORTHEASTERN CARIBBEAN SEA INTO THE CARIBBEAN SEA...
A DEEP LAYER TROUGH COVERS THE AREA FROM THE BAHAMAS
NEAR 24N74W ACROSS EASTERN CUBA TO A CYCLONIC CIRCULATION
CENTER NEAR 16N78W TO WESTERN PANAMA NEAR 9N82W. STRONG SHOWERS
AND THUNDERSTORMS ARE IN THE SOUTHWESTERN CORNER OF THE AREA 
FROM 10N TO 13N BETWEEN 81W AND 83W. THE GENERAL SITUATION TO 
THE WEST AND NORTHWEST OF THE TROUGH...MIDDLE TO UPPER LEVEL DRY 
AIR...AND CLUSTERS OF SCATTERED TO BROKEN LOW TO MIDDLE LEVEL 
CLOUDS AND POSSIBLE SHOWERS. THE CARIBBEAN SEA TO THE EAST OF 
THE TROUGH IS FILLED WITH CLOUDY SKIES. STRONG SHOWERS AND  
THUNDERSTORMS FROM 14N TO 17N BETWEEN 62W AND 65W. ISOLATED 
MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE WITHIN
90 TO 150 NM ON EITHER SIDE OF 13N80W 17N76W 22N72W. AN UPPER 
LEVEL RIDGE RUNS FROM EASTERN COASTAL VENEZUELA TO 16N64W TO
25N61W BEYOND 32N59W. A SURFACE TROUGH IS ALONG 24N63W 21N71W 
16N74W 12N76W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND 
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND POSSIBLE 
THUNDERSTORMS FROM 17N TO 26N BETWEEN 55W AND 68W. 

THE ATLANTIC OCEAN...
BROAD LARGE SCALE UPPER LEVEL ANTICYCLONIC FLOW IS PRESENT TO 
THE NORTH OF 30N WEST OF 30W. A MIDDLE TO UPPER LEVEL TROUGH 
PASSES THROUGH 32N25W TO 28N34W TO A CYCLONIC CIRCULATION CENTER 
NEAR 25N38W TO 19N46W TO 17N53W. BROAD LARGE SCALE UPPER LEVEL 
ANTICYCLONIC FLOW MOVES FROM THE ITCZ TOWARD THE 32N35W 28N34W 
17N53W TROUGH...AND THEN IT CURVES ANTICYCLONICALLY 
NORTHEASTWARD. THE RIDGE IS ALONG 11N59W 13N36W TO JUST SOUTH
OF THE CAPE VERDE ISLANDS. A SURFACE RIDGE RUNS FROM 33N9W TO
THE CANARY ISLANDS TO A 1020 MB HIGH PRESSURE CENTER NEAR 26N30W 
TO 26N45W TO A SECOND 1020 MB HIGH PRESSURE CENTER NEAR 29N54W
TO 31N63W.

$$
MT