[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 28 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 ENTERING THE E
TROPICAL ATLC NEAR 8N16W TO 6N15W WHERE THE ITCZ AXIS CONTINUES
ALONG 4N21W 3N27W 3N35W THEN S OF THE EQUATOR NEAR 48W. CLUSTERS
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-6N
BETWEEN 2W-42W.

...DISCUSSION...

GULF OF MEXICO...
A VERY NARROW UPPER TROUGH EXTENDS FROM NE FLORIDA S ACROSS THE
E GULF INTO THE CARIBBEAN THROUGH THE YUCATAN CHANNEL. A SURFACE
TROUGH IS ALONG THE E SIDE OF THE UPPER TROUGH EXTENDING AT
28/0900 UTC ACROSS S FLORIDA INTO THE FAR SE GULF NEAR 25N81W
ACROSS THE LOWER FLORIDA KEYS THEN TO ACROSS CUBA INTO THE NW
CARIBBEAN NEAR 23N89W. SCATTERED TO HEAVY SHOWERS/ISOLATED
THUNDERSTORMS ARE E OF THE SURFACE TROUGH OUT OF THE GULF AND
WITHIN 60 NM W OF THE TROUGH. A BROAD UPPER RIDGE DOMINATES THE
REMAINDER OF THE GULF WITH A RIDGE AXIS EXTENDING FROM THE E
PACIFIC REGION ACROSS MEXICO NEAR TUXPAN TO THE N GULF COAST
NEAR PENSACOLA FLORIDA. A SURFACE RIDGE EXTENDS FROM W ATLC
ACROSS FLORIDA TO OVER THE GULF TO 91W WITH A 1019 MB HIGH OFF
THE FLORIDA COAST JUST NEAR TAMPA. THIS SURFACE RIDGE CONTINUES
TO PRODUCE SOUTHERLY RETURN FLOW ACROSS MOST OF THE N GULF N OF
26N W OF 86W. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR
COVERS MOST OF THE GULF GIVING WAY TO THE SURFACE TROUGH OVER
THE FAR SE GULF BUT LEAVING THE REMAINDER OF THE GULF UNDER
CLEAR SKIES AGAIN THIS MORNING. THE SURFACE RIDGE EXTENDING FROM
THE W ATLC WILL SHIFT N ACROSS THE N GULF COAST TONIGHT THEN
SHIFT N OF AREA ON SUN. THE SURFACE TROUGH WILL MOVE NW INTO THE
E GULF THROUGH TONIGHT BEFORE DISSIPATING. A SECOND BROADER
SURFACE TROUGH WILL MOVE W THROUGH THE STRAITS OF FLORIDA SUN
CONTINUE W TO THE S CENTRAL GULF ON TUE BEFORE WEAKENING OVER
THE W GULF ON WED.

CARIBBEAN SEA...
THE VERY NARROW UPPER TROUGH EXTENDS OVER THE FAR W CARIBBEAN
FROM THE E GULF OF MEXICO THROUGH THE YUCATAN CHANNEL TO OVER
HONDURAS. A SURFACE TROUGH IS ALONG THE E SIDE OF THE UPPER
TROUGH EXTENDING AT 28/0900 UTC FROM 20N84W ACROSS CUBA NEAR
23N89W INTO THE GULF OF MEXICO. SCATTERED TO HEAVY SHOWERS/
ISOLATED THUNDERSTORMS ARE N OF 18N E OF THE SURFACE TROUGH TO
79W AND WITHIN 60 NM W OF THE TROUGH. SCATTERED SHOWERS ARE N OF
16N BETWEEN 73W-79W. A BROAD UPPER RIDGE DOMINATES THE REMAINDER
OF THE CARIBBEAN BASIN E OF 82W ANCHORED JUST W OF THE WINDWARD
ISLANDS. A WEAK SURFACE TROUGH IS BENEATH THIS UPPER RIDGE
EXTENDING FROM 16N78W TO 12N80W AND IS EMBEDDED WITHIN DENSE
CLOUD COVER WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED SHOWERS
WITHIN 250 NM W OF THE TROUGH. FRESH EASTERLY TRADE WINDS COVER
THE E INTO THE CENTRAL CARIBBEAN THROUGH MON THEN WILL DIMINISH
SLIGHTLY TUE AND WED.

ATLANTIC OCEAN...
THE BROAD UPPER RIDGE OVER THE CARIBBEAN EXTENDS TO OVER THE W
AND CENTRAL ATLC S OF 32N W OF 47W. A SURFACE TROUGH IS ALONG
THE W SIDE OF THE UPPER RIDGE EXTENDING AT 28/0900 UTC ACROSS S
FLORIDA FROM JUST OFFSHORE NEAR WEST PALM BEACH INTO THE FAR SE
GULF THEN INTO THE NW CARIBBEAN. SCATTERED TO HEAVY SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 250 NM W AND WITHIN 60 NM E OF
THE SURFACE TROUGH. SCATTERED SHOWERS ARE S OF 26N BETWEEN
70W-77W. A SURFACE RIDGE EXTENDS FROM THE CENTRAL ATLC ALONG 30N
TO 70W THEN ACROSS CENTRAL FLORIDA INTO THE GULF OF MEXICO WITH
A WEAKNESS IN THE IMMEDIATE VICINITY OF A SURFACE TROUGH THAT
EXTENDS FROM 28N64W TO 24N70W. AN UPPER TROUGH OVER THE E ATLC
EXTENDS S TO 10N E OF 46W SUPPORTING A DISSIPATING COLD FRONT
THAT ENTERS THE REGION OFF WESTERN SAHARA AFRICA NEAR 26N14W S
OF THE CANARY ISLANDS TO 24N19W WITH A SURFACE TROUGH FURTHER SW
EXTENDING FROM 19N40W TO 12N47W. ANY SHOWER ACTIVITY IS INLAND
OVER AFRICA. THE SURFACE TROUGH MOVING ACROSS S FLORIDA WILL
EXIT THE STRAITS OF FLORIDA THIS MORNING. THE SURFACE RIDGE
EXTENDING ACROSS THE W ATLC WILL SHIFT N TO ALONG 31N TONIGHT
THEN WEAKEN AND SHIFT E SUN AHEAD OF A COLD FRONT THAT WILL PASS
THROUGH BERMUDA ON SUN NIGHT AND MOVE INTO THE CENTRAL ATLC MON.
A BROAD SURFACE TROUGH S OF 25N ALONG 78W WILL AMPLIFY N ACROSS
THE NW BAHAMAS ON SUN AND DRIFT W THROUGH THE FLORIDA STRAITS
THROUGH MON NIGHT THEN INTO THE GULF OF MEXICO.

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

$$
PAW





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