[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282339
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED APR 28 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC...

...THE ITCZ...
THE ITCZ IS CENTERED FROM N LIBERIA NEAR 7N12W ALONG 5N20W 4N30W
3N40W AND INTO NE BRAZIL NEAR EQ50W. ISOLATED MODERATE/STRONG
CONVECTION IS WITHIN 100 NM N OF THE AXIS 22W-39W. SIMILAR
ACTIVITY IS ALSO FROM 4N-6N BETWEEN 41W-47W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO BUILD ACROSS THE GULF OF MEXICO
ANCHORED BY A 1019 MB HIGH S OF PANAMA CITY FLORIDA...AND A 1018
MB HIGH OVER W MISSISSIPPI KEEPING MUCH OF THE GULF COAST UNDER
FAIR CONDITIONS. WATER VAPOR IMAGERY INDICATES MID TO UPPER
LEVEL MOISTURE IS BEING DRAWN FROM THE E PACIFIC ACROSS THE
YUCATAN AND INTO THE GULF OF MEXICO AROUND AN UPPER LEVEL RIDGE
CENTERED N OF VENEZUELA SUPPORTING HIGH CLOUDS ACROSS MUCH OF
THE AREA. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES
ENHANCED MOISTURE ACROSS THE SW GULF WHERE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS RANGE FROM 20W-24W E OF 94W.
EXPECT THE SURFACE RIDGE TO GRADUALLY SHIFT EWD ALLOWING SLY
RETURN FLOW TO INCREASE ACROSS THE W GULF. MOISTURE ACROSS THE
SW GULF SHOULD REMAIN IN PLACE SUPPORTING ISOLATED SHOWERS
ACROSS THAT PORTION OF THE BASIN.

THE CARIBBEAN SEA...
A DISSIPATING STATIONARY FRONT CONTINUES TO LINE THE NW
CARIBBEAN FROM ERN CUBA NEAR 21N77W TO THE YUCATAN PENINSULA AT
20N87W. SCATTERED SHOWERS ARE WITHIN 75 NM N OF THE AXIS. A
CLUSTER OF THUNDERSTORMS ARE ALSO S OF THE FRONT ACROSS E CUBA.
THE FRONT IS SUPPORTED BY AN UPPER LEVEL LONGWAVE TROUGH ACROSS
THE W ATLC. HOWEVER...AN UPPER LEVEL RIDGE COVERS THE CARIBBEAN
CENTERED N OF VENEZUELA. WATER VAPOR IMAGERY INDICATES UPPER
LEVEL DRY AIR ACROSS THE MAJORITY OF THE BASIN E OF THE FRONT
SUPPORTING GENERALLY FAIR WEATHER OVER THE REMAINDER OF THE
AREA. SCATTERED SHOWERS/THUNDERSTORMS REMAIN OVER MUCH OF
CENTRAL AMERICA...AND NRN COLOMBIA DUE TO SURFACE CONVERGENCE
NEAR THE E PACIFIC ITCZ WHICH CROSSES SRN COSTA RICA AND LINES
THE PANAMA COAST. EXPECT THE FRONT TO CONTINUE TO DISSIPATE
WHILE MOISTURE REMAINS ACROSS CENTRAL AMERICA AND THE NW
CARIBBEAN.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH CONTINUES TO IMPACT THE WRN ATLC THIS
EVENING WITH A DISSIPATING COLD FRONT EXTENDING FROM 31N61W
ALONG 26N67W TO 23N71W WHERE IT BECOMES STATIONARY TO ERN CUBA
NEAR 21N77W AND INTO THE NW CARIBBEAN. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 250 NM E OF THE FRONT
N OF 25N...AND WITHIN 75 NM EITHER SIDE OF THE AXIS S OF 25N. A
REINFORCING COLD FRONT IS W OF THE DISSIPATING FRONT ENTERING
THE DISCUSSION NEAR 32N65W ALONG 27N70W 24N76W. THIS IS A FAST
MOVING FRONT THAT WILL EVENTUALLY TAKE OVER THE DISSIPATING
FRONT AND MERGE INTO ONE BOUNDARY. AN UPPER LEVEL LONGWAVE
TROUGH COVERS THE W ATLC SUPPORTING THE FRONTAL SYSTEM. UPPER
LEVEL DIFFLUENCE TO THE E OF THE UPPER TROUGH IS ALSO ENHANCING
SHOWER/THUNDERSTORM ACTIVITY ALONG THE DISSIPATING SURFACE
BOUNDARY. FARTHER E...A SURFACE RIDGE DOMINATES ANCHORED BY A
1030 MB HIGH NEAR 34N34W PROVIDING GENERALLY FAIR WEATHER ACROSS
MUCH OF THE REMAINDER OF THE BASIN. HOWEVER...A SURFACE
TROUGH...REMNANTS OF A FRONTAL BOUNDARY...PROTRUDES INTO THE
RIDGE ALONG 29N22W 23N32W 20N44W. POSSIBLE ISOLATED SHOWERS ARE
WITHIN 75 NM EITHER SIDE OF THE TROUGH. ALOFT...AN UPPER LEVEL
RIDGE EXTENDS FROM THE CARIBBEAN TO THE NE ACROSS THE AZORES
ISLANDS SUPPORTING THE SURFACE RIDGE ACROSS THE CENTRAL/E ATLC.
A NARROW UPPER LEVEL TROUGH EXTENDS FROM THE CANARY ISLANDS TO
THE NE BRAZIL COAST SUPPORTING THE SURFACE TROUGH. THIS UPPER
LEVEL TROUGH IS MOST LIKELY ENHANCING CONVECTION ALONG THE ERN
PORTION OF THE ATLC ITCZ.

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

$$
WALTON





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