[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 29 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC...

...THE ITCZ...

THE ITCZ IS CENTERED FROM FROM THE NORTHERN LIBERIA COAST NEAR
6N11W WESTWARD ALONG 5N20W 4N30W 3N40W INTO THE NORTHEASTERN
COAST OF BRAZIL NEAR 1.5N50W. SCATTERED MODERATE TO STRONG
CONVECTION IS IN THE COASTAL WATERS OF AFRICA NEAR COTE
D'VOIRE...LIBERIA...AND SIERRA LEONE. MODERATE TO STRONG
CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE AXIS BETWEEN 16W
AND 25W. ELSEWHERE WEST OF 33W...MODERATE TO STRONG CONVECTION
IS WITHIN 160 NM ON EITHER SIDE OF THE AXIS.

...DISCUSSION...

GULF OF MEXICO...
MARINE OBSERVATIONS ACROSS THE BASIN SHOW A MODERATE
SOUTHEASTERLY COMPONENT ACROSS THE BASIN. AN UPPER LEVEL RIDGE
OF HIGH PRESSURE IS BUILDING OVER THE REGION...SUPPRESSING ANY
DEEP CONVECTION NORTH OF 25N. HOWEVER...A BROAD UPPER LEVEL
LONGWAVE IS MOVING ACROSS THE GULF...NOTED BY STRONG SUBSIDENCE
OF DRY AIR NORTH OF 24N WEST OF 90W...MOVING SOUTHEASTWARD.
MOIST UNSTABLE AIR FROM CENTRAL AMERICA IS MOVING OVER THE
SOUTHEAST CORNER OF THE BASIN. THIS SHARP CONTRAST BETWEEN DRY
SUBSIDENT AIR AND MOIST UNSTABLE AIR IS LEADING TO AN AREA OF
WEAK TO MODERATE CONVECTION EAST OF 90W SOUTH OF 24N. DOPPLER
RADAR IMAGERY INDICATES SHOWERS IN THIS REGION MOVING INTO
SOUTHERN FLORIDA AND THE FLORIDA STRAIGHTS. OVER THE NEXT 24
HOURS...COMPUTER MODELS CONTINUE TO BRING SHOWERY WEATHER OVER
THE SOUTHEAST CORNER OF THE BASIN INCLUDING THE SOUTHERN FLORIDA
PENINSULA.

THE CARIBBEAN SEA...
ABUNDANT MID TO UPPER LEVEL MOISTURE FROM CENTRAL AMERICA AND
EASTERN TROPICAL PACIFIC CONTINUES TO MOVE OVER THE FAR
NORTHWEST BASIN...FUELING A LINGERING SURFACE TROUGH THAT
CROSSES CENTRAL CUBA AND CONTINUES WEST-SOUTHWESTWARD INTO FAR
WESTERN BASIN...ENTERING CENTRAL AMERICA THROUGH BELIZE TO
CENTRAL GUATEMALA. MODERATE TO STRONG CONVECTION IS WITHIN 120
NM ON EITHER SIDE OF THE BOUNDARY WEST OF 84W...AND WITHIN 60 NM
EITHER SIDE OF THE BOUNDARY EAST OF 84W. THIS FRONTAL BOUNDARY
IS EXPECTED TO START WEAKENING OVER THE NEXT 24 HOURS. ONLY A
FEW SHOWERS MAY REMAIN OVER THE AREA...ESPECIALLY OVER CUBA.
PART OF THE ITCZ IS OVER NORTHERN COLOMBIA...PANAMA...COSTA
RICA...AND SOUTHERN NICARAGUA...AFFECTING THE WATERS NEAR THE
COAST OF THESE COUNTRIES. COMPUTER MODELS CONTINUE TO SHOW
CONVECTION IN THIS REGION THE REST OF THE WORK WEEK. ELSEWHERE
ACROSS THE CARIBBEAN SEA EAST OF 75W...FAIR WEATHER IS OBSERVED
ACROSS THIS REGION WITH A SURFACE PRESSURE GRADIENT
COMPARATIVELY WEAK...AND LIGHT TO MODERATE TRADE WINDS.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OF HIGH PRESSURE IS SLOWLY ENTERING THE FAR
WESTERN ATLANTIC. THE SURFACE HIGH PRESSURE SYSTEM IS NEAR
29N75W. THEREFORE...FAIR WEATHER IS OBSERVED NORTH OF 24N WEST
OF 60W. A COLD FRONT ENTERS THE CENTRAL ATLANTIC AREA OF
DISCUSSION EXTENDING WEST-SOUTHWEST ALONG 32N50W 25N60W 22N70W
BECOMING A SURFACE TROUGH THAT CROSSES THE SOUTHERN BAHAMAS AND
CONTINUES OVER CENTRAL CUBA. MODERATE CONVECTION IS WITHIN 90 NM
ON EITHER SIDE OF THE COLD FRONT AND 60 NM ON EITHER SIDE OF THE
SURFACE TROUGH. THIS FRONTAL SYSTEM IS SUPPORTED BY A BRAD UPPER
LEVEL SHORTWAVE TROUGH THAT PASSES THROUGH THE WESTERN ATLANTIC.
AN UPPER LEVEL RIDGE OF HIGH PRESSURE COVERS MOST OF THE EASTERN
BASIN SUPPRESSING DEEP CONVECTION EAST OF 45W. THE STRONGEST
AREA OF SURFACE HIGH PRESSURE IS NEAR 36N30W. COMPUTER MODELS
INDICATE THE COLD FRONT WILL SLOWLY DETACH FROM THE SURFACE
TROUGH AND CONTINUE TO MOVE EASTWARD WITH CONVECTION AHEAD OF
IT. THE SURFACE TROUGH WILL REMAIN NEAR THE SAME AREA AND WEAKEN
WITH LESS ACTIVITY EMBEDDED IN IT.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$

GARCIA


WWWW
This weather bulletin was brought to you by:
www.nashvilleweather.net