[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231103
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 23 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.

...SPECIAL FEATURES...

A 1011 MB NON-TROPICAL LOW CONTINUES TO SPIN ABOUT 500 NM S OF
BERMUDA NEAR 24N65W MOVING S NEAR 10 KT. THIS IS A DEEP LAYERED
LOW WITH THE UPPER LEVEL LOW NEAR 26N62W. WATER VAPOR SATELLITE
IMAGERY SHOWS DRY AIR ALOFT NEARLY SURROUNDS THE UPPER LOW
EXCEPT TO THE NE. A SURFACE TROUGH EXTENDS FROM THE SURFACE LOW
E TO 24N57W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE FROM 22N-25N BETWEEN 61W-65W. UPPER LEVEL
WINDS ARE INCREASINGLY LESS CONDUCIVE FOR DEVELOPMENT AND ARE
FORECAST TO BECOME HIGHLY UNFAVORABLE FOR DEVELOPMENT DURING THE
NEXT 48 HOURS. THE DRY AIR ALOFT ALONG WITH UNFAVORABLE UPPER
LEVEL WINDS ARE EXPECTED TO HINDER FURTHER DEVELOPMENT.

...ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 7N11W 3N19W CROSSING THE EQUATOR
NEAR 35N CONTINUING S OF THE EQUATOR TO INLAND OVER SOUTH
AMERICA. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE
FROM 6N TO S OF THE EQUATOR BETWEEN 5W-14W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N TO S
OF THE EQUATOR BETWEEN 19W-29W AND FROM 2N TO S OF THE EQUATOR
BETWEEN 35W-44W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH REMAINS OVER THE CENTRAL PLAIN STATES MOVING
ACROSS THE UPPER MISSISSIPPI VALLEY WITH A SURFACE TROUGH AND
DRY LINE INLAND OVER CENTRAL TEXAS AND MEXICO. A DRY AND STABLE
AIRMASS REMAINS ACROSS THE GULF WITH AN UPPER HIGH OVER THE
FLORIDA PENINSULA. THIS DRY AIRMASS IS LIMITING SHOWER ACTIVITY
OVER THE GULF WATERS THIS MORNING WITH SOME PATCHES OF HAZE
OVER THE NW GULF N OF 27N W OF 89W. A SURFACE RIDGE CONTINUES TO
BUILD FROM THE NE GULF TO THE CENTRAL GULF GIVING THE AREA E TO
SE SURFACE FLOW WHICH WILL CONTINUE THROUGH TUE AHEAD OF THE
NEXT COLD FRONT THAT WILL MOVE OFF THE TEXAS COAST WED MORNING.
THIS COLD FRONT WILL RACE E AND EXTEND FROM THE FLORIDA BIG BEND
TO THE BAY OF CAMPECHE LATE WED NIGHT.

CARIBBEAN SEA...
BROAD UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED IN THE W
TROPICAL ATLC DRAWING UPPER LEVEL MOISTURE ACROSS THE E
CARIBBEAN. STRONG HIGH PRESSURE OVER THE FAR W ATLC WILL PRODUCE
AN AREA OF FRESH NE WINDS OVER THE N CARIBBEAN INCLUDING THE
WINDWARD AND MONA PASSAGES THROUGH SUN BRINGING A PATCHES OF LOW
LEVEL CLOUDS AND SCATTERED SHOWERS TO THE AREA FROM 16N-20N
BETWEEN 70W-82W. BROAD PRESSURE GRADIENT ACROSS THE REMAINDER OF
THE CARIBBEAN IS PRODUCING LIGHT TO MODERATE NE TO E TRADE WINDS
ACROSS THE REMAINDER OF THE AREA. THESE TRADE WINDS ARE BRINGING
PATCHES OF LOW LEVEL CLOUDS OVER THE SE CARIBBEAN AND COUPLED
WITH THE UPPER LEVEL MOISTURE ARE GENERATING SCATTERED SHOWERS
OVER THE SE CARIBBEAN S OF A LINE FROM GUADELOUPE IN THE LEEWARD
ISLANDS TO LA GUAJIRA PENINSULA OF COLOMBIA LEAVING THE
REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES THIS MORNING.

ATLANTIC OCEAN...
SEE SPECIAL FEATURES ABOVE FOR THE 1011 MB LOW/TROUGH IN THE
W/CENTRAL ATLC. AN UPPER TROUGH IS OVER THE NW ATLC DIPPING INTO
THE DISCUSSION AREA N OF 28N BETWEEN 60W-75W SUPPORTING A
STATIONARY FRONT THAT ENTERS THE W ATLC NEAR 32N57W TO 29N64W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 28N-30N
BETWEEN 59W-62W. AN ELONGATED N/S UPPER LOW IS OVER THE
E/CENTRAL ATLC NEAR 31N40W WITH AN UPPER RIDGE BETWEEN THIS
UPPER LOW AND THE UPPER LOW ASSOCIATED WITH THE SPECIAL
FEATURES. THIS UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO
GENERATE AN AREA OF SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS N OF 22N BETWEEN 47W-58W. THE REMAINDER OF THE
CENTRAL AND E ATLC ARE DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED BY A 1031 MB HIGH SE OF THE AZORES PROVIDING FAIR
WEATHER E OF 47W. BROAD UPPER RIDGE DOMINATES THE TROPICAL ATLC.

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

$$
PAW



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