[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI APR 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...THE ITCZ...

FROM THE NORTHERN LIBERIAN COAST NEAR 7N11W TO 3N20W TO THE
EQUATOR AT 27W TO 2N33W...BECOMING INDISTINCT AT THE EQUATOR
AND 38W. SCATTERED MODERATE TO STRONG THUNDERSTORMS WERE NOTED
WITHIN 60-90 NM N OF THE AXIS BETWEEN 31W AND 36W. SCATTERED
MODERATE ISOLATED STRONG THUNDERSTORMS WERE NOTED WITHIN 120 NM
N OF THE AXIS BETWEEN 14W AND 17W...AND FROM 3N TO 6N BETWEEN
24W AND 30W. SCATTERED TO NUMEROUS STRONG THUNDERSTORMS WERE
NOTED WITHIN 90 NM OF THE COAST OF SOUTHERN LIBERIA.

...DISCUSSION...

THE GULF OF MEXICO...

STRONG SUBSIDENCE PREVAILED AT THE UPPER LEVELS OVER THE GULF OF
MEXICO IN AN AREA OF MODERATE UPPER LEVEL WESTERLY WINDS IN THE
WAKE OF A DEPARTING TROUGH MOVING OFF THE SE U.S. COAST. A
AS OF 1500 UTC A COLD FRONT EXTENDED FROM JUST N OF FORT
PIERCE TO PORT CHARLOTTE IN THE STATE OF FLORIDA...THEN BECOMES
A DISSIPATING STATIONARY FRONT NEAR 25N85W AND CONTINUES TO
22N94W. VISIBLE SATELLITE IMAGERY STILL DEPICTS A WELL DEFINED
ROPE CLOUD WITH ISOLATED SHOWERS ASSOCIATED WITH THE FRONT INTO
THE GULF. PATCHES OF LOW CLOUDS COVER THE SOUTHWEST GULF OF BAY
OF CAMPECHE FROM 20N TO 25N WEST OF 90W TO THE EAST COAST OF
MEXICO. THE LOW CLOUDS WERE STREAMING NORTHWARD AS SURFACE AND
LOW LEVEL WINDS INCREASE OVER THE WESTERN GULF. VISIBLE
SATELLITE IMAGERY ALSO INDICATED AREAS OF SMOKE AND HAZE OVER
THE BAY OF CAMPECHE ORIGINATING FROM FIRES OVER THE YUCATAN
PENINSULA. SURFACE OBSERVATIONS INDICATED VISIBILITIES OF 3 NM
IN SMOKE AND HAZE. SKIES OVER THE NORTHERN THIRD OF THE GULF OF
MEXICO WERE CLEAR WITH LIGHT TO MODERATE EASTERLY WINDS ALONG
THE SOUTHERN PERIPHERY OF HIGH PRESSURE LOCATED OVER LOUISIANA.

THE CARIBBEAN SEA...

A BROAD BELT OF UPPER LEVEL WESTERLY WINDS IS SWEEPING ACROSS
THE CARIBBEAN WITH THE FLOW BECOMING MORE CYCLONIC OVER
HISPANIOLA AND ALONG 70W IN ASSOCIATION WITH THE SOUTHWESTERN
END OF AN UPPER LEVEL TROUGH OVER THE SOUTHWEST NORTH ATLANTIC.
AT THE SURFACE...BRISK EASTERLY TRADES CONTINUE OVER MOST OF THE
BASIN WITH A 1342 UTC ASCAT PASS INDICATING STEADY 20 KT WINDS
OVER THE EASTERN CARIBBEAN N OF 14N. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WERE OCCURRING OVER THE WINDWARD ISLANDS
BETWEEN ST. LUCIA AND GUADELOUPE AND EXTENDED WESTWARD WITHIN
45 NM EITHER SIDE OF A LINE THROUGH 15N64W TO 16N70W. SCATTERED
SHOWERS AND THUNDERSTORMS WERE ALSO OCCURRING IN THE GULF OF
HONDURAS JUST WEST OF ROATAN AND EXTENDING OVER HONDURAS.
SCATTERED TRADE WIND CUMULUS WERE INDICATED ELSEWHERE ACROSS THE
CARIBBEAN SEA.

THE ATLANTIC OCEAN...

A COMPLEX UPPER LEVEL CYCLONIC CIRCULATION CENTER WITH A MEAN
CENTER NEAR 27N58W IS DRIFTING WESTWARD WITH THE ASSOCIATED
CYCLONIC FLOW COVERING THE AREA TO THE NORTH OF 20N BETWEEN 45W
AND 70W. A SHORTWAVE TROUGH WAS ROTATING AROUND THE SOUTHWEST
PORTION OF THE LARGER CYCLONIC CIRCULATION SWEEPING ACROSS
HISPANIOLA INTO THE CARIBBEAN. A SHORTWAVE RIDGE-TROUGH
COUPLET COVERS THE ATLANTIC W OF 70W WITH THE TROUGH EXTENDING
NORTHWARD ALONG THE EASTERN SEABOARD OF THE U.S. A BROAD FLAT
UPPER LEVEL RIDGE EXTENDED ACROSS THE DEEP TROPICS ALONG 7N
WITH A BROAD AREA OF CONFLUENT WESTERLY FLOW ALOFT DOMINATING
THE REMAINDER OF THE TROPICAL AND SUBTROPICAL ATLANTIC FROM 10N
TO 30N EAST OF 40W. AT THE SURFACE A COLD FRONT EXTENDED FROM
31N78W TO THE FLORIDA EAST COAST NEAR FORT PIERCE. SCATTERED
SHOWERS AND THUNDERSTORMS WERE NOTED WITHIN 90 NM E OF THE FRONT
N OF 27N MAINLY OVER THE ATLANTIC OCEAN WITH AN ISOLATED
THUNDERSTORM NEAR PALM BEACH FLORIDA. ADDITIONAL SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS EXTENDED OFF THE WINDWARD
ISLANDS INTO THE ADJACENT ATLANTIC OCEAN WEST OF 55W.
GENERALLY FAIR SKIES PREVAILED ELSEWHERE OVER THE  ATLANTIC.

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

$$
COBB



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