[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121058
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE APR 12 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 06N10W 02N22W CROSSING THE EQUATOR
NEAR 26W THEN TO 04S30W AND INTO NE BRAZIL NEAR 05S38W. WIDELY
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM
01N-05N BETWEEN 14W-29W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH CONTINUES TO PROGRESS ACROSS THE
SE CONUS THIS MORNING SUPPORTING A COLD FRONT THAT AT 12/0900
UTC ENTERS THE GULF OF MEXICO NEAR 30N87W THEN SW ALONG 28N90W
TO 25N95W THEN INLAND ACROSS THE SOUTHERN MEXICO GULF COAST NEAR
20N96W. WATER VAPOR IMAGERY INDICATES FAIRLY DRY CONDITIONS AND
OVERALL STRONG SUBSIDENCE ALOFT OVER MUCH OF THE GULF SO
CONVECTION WITH THE FRONT IS LIMITED TO A PRE-FRONTAL SURFACE
TROUGH EXTENDING FROM THE FLORIDA PANHANDLE NEAR 30N85W TO
28N89W IMPACTING THE COASTAL WATERS WITH ISOLATED SHOWERS N OF
28N BETWEEN 83W-88W. ISOLATED LOW-TOPPED SHOWERS ARE ALSO
POSSIBLE WITHIN 45 NM EITHER SIDE OF THE COLD FRONT. STRONGER NE
WINDS TO 20 KT ON RECENT SHIP AND BUOY OBSERVATIONS ARE NOTED NW
OF THE FRONT DUE TO AN INCREASED PRESSURE GRADIENT BETWEEN THE
FRONTAL TROUGH AND A 1021 MB HIGH CENTERED OVER CENTRAL TEXAS
NEAR ABILENE. THE HIGH IS FORECAST TO SHIFT EASTWARD THROUGH
EARLY WEDNESDAY WITH AXIS ALONG 90W PROVIDING THE GULF WITH
LIGHT ANTICYCLONIC WINDS AND GENERALLY FAIR CONDITIONS.

CARIBBEAN SEA...
DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY
ACROSS MUCH OF THE WESTERN CARIBBEAN IN ASSOCIATION WITH BROAD
MIDDLE TO UPPER LEVEL TROUGHING EXTENDING FROM THE SW NORTH ATLC
REGION. THE UPPER LEVEL TROUGH AXIS EXTENDS FROM NORTH OF
HISPANIOLA NEAR 20N70W TO PANAMA NEAR 08N78W. THIS VERY DRY AIR
ALOFT IS SUPPORTIVE OF CLEAR SKIES W OF 70W AND IS EXPECTED TO
REMAIN IN PLACE THROUGH THURSDAY AS THE UPPER LEVEL TROUGH MOVES
LITTLE. THE HIGHER POTENTIAL CONVECTIVE WEATHER REMAINS EAST OF
THE TROUGH AXIS ALONG 70W. E OF 70W...E-NE TRADES CONTINUE WITH
A SURFACE TROUGH ANALYZED FROM 12N65W TO 18N63W N OF ANGUILLA.
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING E OF A
LINE FROM EASTERN PUERTO RICO NEAR 18N66W TO ARUBA NEAR 12N70W.
THIS AREA IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH EARLY
WEDNESDAY AS A FRONTAL TROUGH TO THE NORTH OVER THE SW NORTH
ATLC SHIFTS E-NE OVER THE NEXT 24 TO 36 HOURS. HIGH VALUES OF
TOTAL PRECIPITABLE WATER ARE NOTED OVER THE SE CARIBBEAN
COINCIDING WITH THE SURFACE TROUGH AND THIS ADDED LOW-LEVEL
MOISTURE WILL CONTINUE TO SUPPORT SCATTERED SHOWER ACTIVITY E OF
70W OVER THE NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC THAT
SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N44W
EXTENDING SW AS A DISSIPATING STATIONARY FRONT TO 25N62W. A
PRE-FRONTAL TROUGH IS ANALYZED FROM THE FRONT NEAR 29N50W TO
22N56W. WHILE MOST OF THE LOW-LEVEL CONVERGENCE IN THE VICINITY
OF THE BOUNDARIES W OF 50W REMAINS WEAK...THE STRONGEST UPPER
LEVEL DYNAMICS EVIDENT ON WATER VAPOR IMAGERY N OF 26N E OF 50W
CONTINUE TO SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS FROM
27N TO BEYOND 32N BETWEEN 41W-48W. SW OF THE FRONT...A WEAK 1015
MB LOW IS CENTERED NEAR 22N62W WITH VERY LITTLE ASSOCIATED
SHOWER ACTIVITY. MOST CLOUDINESS AND POSSIBLE ISOLATED SHOWERS
FROM 10N-23N BETWEEN 52W-63W ARE ADVECTING NORTHEASTWARD FROM
THE EASTERN CARIBBEAN SEA DUE TO A STRONG UPPER LEVEL TROUGH
ALONG 70W S OF 24N. THE REMAINDER OF THE ATLC E OF 42W IS UNDER
THE INFLUENCE OF A SURFACE RIDGE WITH AXIS EXTENDING FROM THE
AZORES NEAR 38N27W TO 25N42W.

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

$$
HUFFMAN




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