[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261032
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU APR 26 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 12N16W TO 7N18W WHERE THE ITCZ CONTINUES ALONG 4N24W
3N30W TO 1N37W THEN S OF THE EQUATOR NEAR 43W. CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION ARE FROM 5N TO THE EQUATOR
E OF 15W TO THE PRIME MERIDIAN AND FROM 2N-7N BETWEEN 16W-32W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM NE FLORIDA SW ACROSS THE GULF TO
THE E BAY OF CAMPECHE AMPLIFYING AN UPPER RIDGE THAT IS INLAND
OVER MEXICO TO THE CENTRAL PLAIN STATES AND E TO THE MISSISSIPPI
VALLEY. A SURFACE RIDGE DOMINATES THE GULF ANCHORED BY A 1020 MB
HIGH OFF THE FLORIDA COAST NEAR 27N84W. THIS SURFACE RIDGE IS
PRODUCING MODERATE TO FRESH SOUTHERLY RETURN FLOW ACROSS MOST OF
THE N GULF. STRONG SUBSIDENCE AND DRY STABLE AIR ARE DOMINATING
THE GULF GIVING THE AREA CLEAR SKIES AGAIN THIS MORNING. A
SHORTWAVE UPPER TROUGH IS MOVING ACROSS THE SE CONUS FROM NE
TENNESSEE TO SW ALABAMA PRODUCING SCATTERED SHOWERS WITHIN 180
NM E OF UPPER TROUGH WHICH ARE MOVING TO OVER THE W FLORIDA
PANHANDLE. SURFACE RIDGE WILL WILL LIFT N TO THE N GULF COAST BY
LATE FRI BEFORE BUILDING OVER THE SE UNITED STATES SAT THROUGH
MON.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE GULF OF MEXICO CUTS ACROSS THE FAR NW
CARIBBEAN. A SURFACE TROUGH EXTENDS FROM THE CENTRAL CARIBBEAN
NEAR 16N78W TO THE COAST OF COLOMBIA NEAR 9N76W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150 NM
EITHER SIDE OF THE TROUGH AXIS. THE REMNANTS OF THE DISSIPATING
STATIONARY FRONT ARE NOW ANALYZED AS A SURFACE TROUGH EXTENDING
FROM THE W/CENTRAL ATLC ACROSS HISPANIOLA NEAR 19N71W TO 15N75W
AND CONTINUES TO GENERATE SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS WITHIN 120 NM OF THE TROUGH INCLUDING ALL
OVER HISPANIOLA AND PORTIONS OF E CUBA. OTHERWISE A BROAD UPPER
RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN BASIN ANCHORED
OVER VENEZUELA WITH A RIDGE AXIS EXTENDING N ACROSS THE LEEWARD
ISLANDS INTO THE CENTRAL ATLC FURTHER ENHANCING THE ACTIVITY
OVER HISPANIOLA. THE FRESH TO STRONG TRADE WINDS COVER MUCH OF
THE CENTRAL AND E CARIBBEAN AND WILL CONTINUE INTO SAT. THE
WESTERN TROUGH WILL TRACK WNW TO THE GULF OF HONDURAS LATE FRI
AND TO INLAND THE YUCATAN PENINSULA SAT.

ATLANTIC OCEAN...
THE BROAD UPPER TROUGH IS OVER THE W ATLC N OF 30N AND CONTINUES
TO SUPPORT A COLD FRONT THAT ENTERS THE W/CENTRAL ATLC NEAR
32N58W EXTENDING TO 28N60W WHERE IT BECOMES STATIONARY TO 23N65W
THEN BECOMES A SURFACE TROUGH ANALYZED TO ACROSS HISPANIOLA INTO
THE CARIBBEAN NEAR 19N71W. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE WITHIN 180/200 NM EITHER SIDE OF THE
FRONT/TROUGH. A SURFACE RIDGE BEHIND THE FRONT COVERS THE W ATLC
INTO THE GULF OF MEXICO AND IS ANCHORED BY A 1022 MB HIGH NEAR
29N71W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF THE
FRONTAL ACTIVITY AND COUPLED WITH THE SURFACE RIDGE IS GIVING
THE W ATLC CLEAR SKIES THIS MORNING. THE UPPER RIDGE OVER THE
CARIBBEAN EXTENDS A RIDGE AXIS ACROSS THE LEEWARD ISLANDS TO
BEYOND 32N50W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE
FRONT/TROUGH. THE UPPER TROUGH OVER THE E ATLC EXTENDS THROUGH
32N25W TO 19N42W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM
26N43W TO 18N39W AND CONTINUES TO GENERATE SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS FROM 18N-23N BETWEEN 30W-39W. A BROAD
SURFACE RIDGE DOMINATES THE ATLC W OF 65W WITH A WEAKNESS IN THE
IMMEDIATE VICINITY OF THE ABOVE SURFACE TROUGH AND IS ANCHORED
WELL N OF THE DISCUSSION AREA. FRONTAL BOUNDARY WILL BECOME A
SURFACE TROUGH TONIGHT AS THE SURFACE RIDGE OVER THE W ATLC
SHIFTS NE TOWARD BERMUDA. TRAILING RIDGE AXIS ALONG 27N WILL
LIFT N TO 30N BY LATE SAT AS A TROUGH MOVES BACK W ACROSS THE SE
AND CENTRAL BAHAMAS...REACHING THE NW BAHAMAS MON. THE SURFACE
RIDGE WILL THEN RETREAT E SUN AND MON IN RESPONSE TO A COLD
FRONT THAT WILL DROP S INTO THE W ATLC BETWEEN N FLORIDA AND
BERMUDA.

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

$$
PAW






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