[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202350
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 06N10W 01N16W CROSSING THE EQUATOR
NEAR 20W THEN ALONG 02S29W 04S39W. WIDELY SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN
12W-27W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY THIS EVENING INDICATES RELATIVELY DRY AIR
ALOFT WITHIN WESTERLY FLOW. THIS UPPER LEVEL PATTERN IS
PROVIDING FOR RATHER BENIGN WEATHER AT THE SURFACE AS A 1023 MB
HIGH IS CENTERED OVER THE FLORIDA PANHANDLE NEAR 30N84W. E-SE
SURFACE WINDS IN THE RANGE OF 10 TO 20 KT ARE ACROSS MUCH OF THE
GULF ON THE SOUTHWESTERN PERIPHERY OF THE SURFACE HIGH. WHILE
MOST OF THE GULF REMAINS UNDER RELATIVELY CLEAR SKIES...THE LAST
FEW VISIBLE SATELLITE IMAGES OF THE DAY SHOW THE ADVECTION OF
SMOKE ORIGINATING IN SOUTHERN MEXICO...THE YUCATAN PENINSULA...
AND CENTRAL AMERICA FROM SEVERAL WILDFIRES. LAND-BASED
OBSERVATIONS ACROSS THE YUCATAN PENINSULA AND ALONG THE TEXAS
AND LOUISIANA GULF COASTS AS WELL AS A FEW OFFSHORE OIL RIGS IN
THE NW GULF SHOW REDUCED VISIBILITIES IN SMOKE AND HAZE. THE
S-SE WINDS ARE EXPECTED TO PERSIST THROUGH THE WEEKEND.

CARIBBEAN SEA...
WEST-SOUTHWESTERLY UPPER LEVEL FLOW IS ACROSS A MAJORITY OF THE
CARIBBEAN SEA ON THE NORTHERN PERIPHERY OF AN UPPER LEVEL RIDGE
WITH AXIS EXTENDING FROM EASTERN VENEZUELA NEAR 07N62W TO
NORTHERN COSTA RICA NEAR 10N84W. MOSTLY DRY AIR AND AN OVERALL
SUBSIDENT ATMOSPHERE IS NOTED ON WATER VAPOR IMAGERY AND IS
FURTHER SUPPORTED IN VISIBLE IMAGERY AS THE BASIN LACKS ANY
SIGNIFICANT AREAS OF DEEP CONVECTION OR ORGANIZED SHOWER
ACTIVITY THIS EVENING. LIGHT TO MODERATE NE TO E TRADES ARE
EXPECTED TO PERSIST AS SURFACE TROUGHING MEANDERS NORTH OF THE
LEEWARD ISLANDS THROUGH LATE SATURDAY.

ATLANTIC OCEAN...
ACROSS THE W ATLC...A 1010 MB LOW IS CENTERED NEAR 23N61W WITH A
SURFACE TROUGH EXTENDING NE FROM THE LOW TO 26N56W. SATELLITE
IMAGERY CONTINUES TO INDICATE THAT UPPER LEVEL SHEAR IS
AFFECTING THE ABILITY OF THE LOW TO GATHER ANY CONVECTIVE
ORGANIZATION THIS EVENING. THIS IS PRIMARILY DUE TO AN UPPER
LEVEL LOW CENTERED TO THE NW OF THE SURFACE LOW NEAR 28N66W
WHICH IS PROVIDING FOR A RATHER LARGE AREA OF MIDDLE TO UPPER
LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL LOW. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING FROM 22N-29N BETWEEN 50W-64W.
THIS SYSTEM CONTINUES TO CREATE AN INCREASED PRESSURE GRADIENT
ACROSS THE W ATLC BETWEEN 50W-70W AS THE SUBTROPICAL RIDGE AXIS
EXTENDS FROM A STRONG 1030 MB HIGH CENTERED NEAR 36N45W TO
BERMUDA NEAR 32N65W TO THE NORTHERN FLORIDA PENINSULA COAST NEAR
JACKSONVILLE AT 30N81W. A GALE WARNING REMAINS IN EFFECT WITHIN
300 NM OF THE LOW IN THE NORTHERN QUADRANT. AN EARLIER ASCAT
PASS FROM 20/1326 UTC DEPICTED THIS WIND FIELD SHOWING E-NE
WINDS IN THE 25 TO 35 KT RANGE. ELSEWHERE...THE REMAINDER OF THE
ATLC E OF 50W IS UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE
ANCHORED BY THE 1030 MB HIGH NORTH OF THE AREA PREVIOUSLY
MENTIONED. A COLD FRONT IS ANALYZED INTO THE FAR NE CORNER OF
ATLC FROM 32N10W TO 27N17W. IT IS EXPECTED TO CONTINUE MOVING
EASTWARD WITH POSSIBLE SHOWERS ACROSS COASTAL MOROCCO AND NW
WESTERN SAHARA.

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

$$
HUFFMAN



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