[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241037
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE APR 24 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 ALONG 7N16W TO 4N17W WHERE THE ITCZ CONTINUES S
OF THE EQUATOR NEAR 23W. SMALL CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 2N-4N E OF 1W ACROSS THE
PRIME MERIDIAN AND FROM 4N TO THE EQUATOR BETWEEN 16W-27W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH CONTINUES TO MOVE FURTHER INTO THE W ATLC
WITH A SURFACE TROUGH AT 24/0900 UTC EXTENDING FROM THE ATLC
ACROSS THE NW CARIBBEAN AND THE N YUCATAN PENINSULA NEAR 21N89W
TO 22 93W IN THE GULF. STRONG SUBSIDENCE A DRY STABLE AIR
DOMINATE THE GULF. A WEAK SURFACE RIDGE REMAINS OVER THE W GULF
ANCHORED BY A 1019 MB HIGH NEAR ALONG THE COAST OF LOUISIANA
NEAR 30N93W. COLD AIR STRATOCUMULUS CLOUDS COVER THE SE GULF S
OF 28N E OF 90W LEAVING THE REMAINDER OF THE GULF WITH CLEAR
SKIES AGAIN THIS MORNING. THE SURFACE HIGH WILL SHIFT SE OVER
THE NW GULF THROUGH TONIGHT THEN MOVE E TO NEAR TAMPA BAY WED
NIGHT AND OUT OF THE GULF THU WITH A RIDGE EXTENDING W TO THE
TEXAS COAST THROUGH SAT. THE COMBINATION OF THE RIDGE AND
DEEPENING LOW PRESSURE IN THE SOUTHERN PLAINS WILL ALLOW FOR
SOUTHERLY RETURN FLOW TO DEVELOP OVER THE FAR W GULF BEGINNING
TONIGHT AND SPREAD E ACROSS MUCH OF THE AREA BY FRI WITH LITTLE
CHANGE INTO SAT.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE GULF OF MEXICO AND W ATLC DIPS S OVER
THE FAR NW CARIBBEAN. A SURFACE TROUGH AT 24/0900 UTC EXTENDS
FROM THE W ATLC ACROSS CUBA NEAR SANTA CLARA OVER THE CAYMAN
ISLANDS TO OVER THE N YUCATAN PENINSULA NEAR 21N88W THEN INTO
THE GULF OF MEXICO WITH ISOLATED SHOWERS WITHIN 45 NM S OF THE
TROUGH. A SECOND SURFACE TROUGH IS TO THE E EXTENDING FROM THE
W/CENTRAL ATLC ACROSS HISPANIOLA ALONG 19N71W 16N73W TO 12N75W
GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
ACROSS THE CENTRAL CARIBBEAN BETWEEN 70W-78W. A BROAD UPPER
RIDGE DOMINATES THE REMAINDER OF THE CARIBBEAN BASIN ANCHORED
OVER SE VENEZUELA. THE CONVERGENCE OF UPPER AND LOWER LEVEL FLOW
IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND
AND WITHIN 90 NM OF THE COAST OF COLOMBIA AND PANAMA BETWEEN
75W-80W WITH SCATTERED SHOWERS WITHIN 90 NM ALONG THE COAST OF
COSTA RICA. THE SURFACE TROUGH WILL DRIFT W REACHING A POSITION
FROM HAITI TO THE CENTRAL CARIBBEAN BY WED EVENING AND FROM E
CUBA TO THE CENTRAL CARIBBEAN THU BEFORE IT BECOMES DIFFUSE.
FRESH NORTHERLY WINDS WILL PREVAIL W OF THE TROUGH WITH MODERATE
TRADE WINDS ELSEWHERE. A W ATLC SURFACE RIDGE BUILDS E WED
AFTERNOON THROUGH FRI.

ATLANTIC OCEAN...
THE BROAD UPPER TROUGH OVER THE GULF OF MEXICO IS MOVING FURTHER
OVER THE W ATLC STILL SUPPORTING A COLD FRONT THAT ENTERS THE
W ATLC NEAR 32N67W EXTENDING TO 27N69W WHERE IT BECOMES
STATIONARY ALONG 24N71W THROUGH THE BAHAMA ISLANDS TO OVER CUBA
NEAR 20N77W. STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF THE
FRONT THUS LIMITING ANY SHOWER ACTIVITY. A SURFACE TROUGH IS
TRAILING THE FRONT EXTENDING FROM 27N75W ACROSS THE BAHAMA
ISLANDS TO OVER CUBA NEAR SANTA CLARA WITH ISOLATED SHOWERS
WITHIN 45 NM EITHER SIDE OF THE TROUGH. A SECOND SURFACE TROUGH
IS TO THE E OF THE FRONT EXTENDING FROM 27N63W ALONG 23N66W
ACROSS HISPANIOLA INTO THE CARIBBEAN NEAR 19N71W WITH SCATTERED
SHOWERS/THUNDERSTORMS WITHIN 75 NM EITHER SIDE OF THE TROUGH
AXIS BETWEEN 21N-25N AND WITH SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS WITHIN 150 NM E AND WITHIN 60 NM W OF THE
REMINDER OF THE TROUGH. THE UPPER RIDGE OVER THE CARIBBEAN
EXTENDS A RIDGE AXIS ACROSS THE PUERTO RICO/VIRGIN ISLANDS TO
BEYOND 32N58W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE
SURFACE TROUGH. AN ELONGATED UPPER LOW IS IN THE CENTRAL ATLC
EXTENDING FROM BEYOND 33N47W TO 25N42W SUPPORTING A SURFACE
TROUGH THAT EXTENDS FROM 34N45W ALONG 30N46W TO 26N42W WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS E OF THE TROUGH AXIS TO
42W. A BROAD SURFACE RIDGE DOMINATES THE ATLC W OF 60W WITH A
WEAKNESS IN THE IMMEDIATE VICINITY OF THE ABOVE SURFACE TROUGH
AND ANCHORED BY A 1029 MB HIGH JUST S OF THE AZORES. THIS IS
GIVING THE REMAINDER OF THE ATLC FAIR WEATHER THIS MORNING. THE
COLD FRONT WILL GRADUALLY WEAKEN AS IT REACHES A POSITION FROM
NEAR BERMUDA TO HISPANIOLA WED. A SURFACE TROUGH WILL EXTEND
FROM W OF BERMUDA TO E CUBA BY EARLY TONIGHT THEN MERGE WITH THE
COLD FRONT WED EVENING FROM JUST S OF BERMUDA TO BETWEEN PUERTO
RICO AND BERMUDA WHERE IT WILL BECOME STATIONARY TO HISPANIOLA.
THE S PORTION OF THE FRONT WILL THEN MOVE BACK W ACROSS THE S
WATERS AS A TROUGH WED NIGHT. IT WILL REACH E CUBA THU THEN
BECOME DIFFUSE NEAR CENTRAL CUBA FRI. HIGH PRESSURE WILL SHIFT E
FROM FLORIDA ACROSS THE W ATLC WED AND THU AND TO OVER THE
N/CENTRAL ATLC FRI.

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

$$
PAW






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