000
AXNT20 KNHC 061127
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU APR 06 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1115 UTC.

...THE ITCZ...

ITCZ 8N12W 4N20W 3N30W 1N40W...THE EQUATOR AT 42W...2S49W.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 2N 
TO 5N BETWEEN 8W AND 13W...AND WITHIN 30 NM TO 45 NM ON EITHER
SIDE OF 4N24W 3N29W 2N33W. WIDELY SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS FROM 3S TO 3N BETWEEN 32W AND 
48W. ISOLATED MODERATE SHOWERS TO POSSIBLE THUNDERSTORMS FROM
3N TO 7N BETWEEN 16W AND 23W...AND FROM 1S TO 3S BETWEEN 18W AND 
26W.

...DISCUSSION...

THE GULF OF MEXICO AND THE ATLANTIC OCEAN WEST OF 55W...
A 1016 MB SURFACE HIGH PRESSURE CENTER IS IN THE NORTHEASTERN
GULF WATERS NEAR 28N87W. HIGH PRESSURE IS MOVING INTO THE AREA 
TO THE NORTHWEST OF A TROUGH...WHICH IS THE REMNANT OF ALREADY 
DISSIPATED COLD FRONT. AN ACTIVE ATLANTIC OCEAN COLD FRONT 
PASSES THROUGH 32N64W TO 28N70W TO THE 26N79W LOW PRESSURE 
CENTER. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE 
FOUND FROM 27N TO 28N BETWEEN 70W AND 74W. ISOLATED MODERATE
SHOWERS ARE WITHIN 60 NM ON EITHER SIDE OF 27N68W 29N64W.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE WITHIN
60 NM ON EITHER SIDE OF 29N64W BEYOND 32N62W. THE TROUGH RUNS 
FROM THE LOW CENTER TO THE STRAITS OF FLORIDA NEAR 24N80W TO 
NORTHWESTERN CUBA COAST TO 24N88W. A TROUGH IS TO THE EAST OF 
THE FRONT ALONG 32N62W 25N65W 20N69W. SCATTERED MODERATE SHOWERS 
AND POSSIBLE THUNDERSTORMS ARE WITHIN 120 NM ON EITHER SIDE OF
19N69W 23N63W 26N60W 29N55W. AN UPPER LEVEL RIDGE RUNS FROM THE 
EAST TEXAS/WESTERN LOUISIANA BORDER NORTHWARD TO ARKANSAS AND 
BEYOND. UPPER LEVEL NORTHWESTERLY WIND FLOW ENTERS THE GULF 
WATERS. THE 06/0600 UTC CIMSS SATELLITE DERIVED WIND DATA ALSO 
SHOW MIDDLE LEVEL NORTHWESTERLY WIND FLOW IN THE OPEN GULF 
WATERS. ONE MAIN DEEP LAYER TROUGH RUNS FROM EASTERN CUBA/
THE WINDWARD PASSAGE TO 25N70W BEYOND 32N65W. AT LEAST ONE OTHER 
SHORTWAVE TROUGH IS MOVING THROUGH THIS LARGER SCALE TROUGH AT 
THIS TIME...WITH ANOTHER FRONT TO THE NORTH OF THE AREA. THE 
MAIN DEEP LAYER TROUGH HAS BEEN SUPPORTING THE SURFACE COLD 
FRONT WHICH EVENTUALLY CONNECTS TO THE 26N79W LOW PRESSURE 
CENTER. 

THE CARIBBEAN SEA...
UPPER TROUGH ORIGINATING FROM A BROAD CYCLONIC CIRCULATION OVER 
THE NORTHEASTERN U.S.A. DIGS TO THE WINDWARD PASSAGE AND 
NORTHWARD. A SEPARATE WIND MAXIMA/BAND OR AREA OF FASTER 
WINDS...CONTINUES TO PASS FROM THE EASTERN PACIFIC OCEAN...
CROSSES COSTA RICA AND PANAMA...AND EVENTUALLY ENDS UP 
SMOTHERING THE CARIBBEAN SEA EAST OF 80W. THE WIND SPEEDS RANGE 
FROM 55 KT TO 90 KT BETWEEN 60W AND 70W...AND FROM 60 KT TO
85 KT BETWEEN 70W AND 80W. MIDDLE TO UPPER LEVEL DRY AIR IS 
NORTHWEST OF THE LINE 20N71W 13N78W 10N83W. MIDDLE TO UPPER 
LEVEL CLOUDS ARE STREAMING NORTHEASTWARD...FOLLOWING THE UPPER 
LEVEL FLOW. BROAD LOW PRESSURE IS IMPLIED IN THE CYCLONIC 
CURVATURE OF THE CARIBBEAN SEA ISOBARS.

THE REST OF THE ATLANTIC OCEAN EAST OF 55W...
LARGE SURFACE HIGH PRESSURE COVERS THE ENTIRE REGION WITH
A 1022 MB HIGH CENTERED NEAR 30N50W...AND A 1021 MB HIGH CENTER
NEAR 25N35W. FAIR WEATHER IS IN THIS PART OF THE ATLANTIC OCEAN.
UPPER RIDGING EXTENDS FROM NORTHERN SOUTH AMERICA NEAR 6N57W
NORTH-NORTHEASTWARD BEYOND 31N48W COVERING A GOOD PART OF THE 
AREA WITH MODERATE/STRONG SUBSIDENCE. AN UPPER TROUGH RUNS FROM
14N32W TO 26N30W BEYOND 33N30W. THE SOUTHERN END OF A COLD FRONT 
REACHES 32N36W. 

$$
MT