[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162347
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT APR 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM SW AFRICA ALONG 5N7W 2N17W 3N30W
1N36W 1N51W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE
ITCZ TO JUST S OF THE EQUATOR BETWEEN 17W-21W WITH CLUSTERS
DOTTING THE AREA FROM 2N TO S OF THE EQUATOR BETWEEN 1W-15W.
SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF ISOLATED STRONG
CONVECTION ARE FROM 6N TO S OF THE EQUATOR BETWEEN 30W-37W.

...DISCUSSION...

GULF OF MEXICO...
THE PRIMARY FOCUS TONIGHT IS THE COLD FRONT OVER THE E CONUS
PRODUCING SEVERE WEATHER FROM SOUTH CAROLINA NORTHWARD. THE COLD
FRONT EXTENDS INTO THE E GULF AT 16/2100 UTC ACROSS NE FLORIDA
NEAR CEDAR KEY ALONG 26N86W TO 24N91W WHERE IT BECOMES
STATIONARY TO 22N94W. ISOLATED SHOWERS ARE OVER THE E GULF
WITHIN 30 NM E OF THE COLD FRONT. THE UPPER TROUGH SUPPORTING
THIS FRONT IS MOVING RAPIDLY OVER THE E CONUS E OF THE
MISSISSIPPI VALLEY INTO THE NE GULF N OF 27N E OF 90W. THE
REMAINDER OF THE GULF IS DOMINATED BY AN UPPER RIDGE AXIS THAT
ACTUALLY EXTENDS ACROSS THE CARIBBEAN INTO THE W ATLC. WEAK
SURFACE RIDGE IS NW OF THE FRONT WITH A 1021 MB HIGH ALONG THE
TEXAS COAST JUST S OF GALVESTON. THE SE PORTION OF THE COLD
FRONT WILL STALL AND BECOME DIFFUSE AS IT MOVES ACROSS THE SE
GULF THROUGH SUN WHILE THE N PORTION WILL MOVE INTO THE W ATLC
LATER THIS EVENING. SURFACE RIDGE BEHIND THE FRONT WILL BUILD
ACROSS THE NE GULF ALLOWING FRESH SE FLOW OVER THE W GULF BY
SUN. SE WINDS WILL INCREASE ACROSS THE ENTIRE GULF EARLY NEXT
WEEK AHEAD OF AN APPROACHING TROUGH MOVING THROUGH THE SOUTHERN
PLAINS.

CARIBBEAN SEA...
AN UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS THE W
CARIBBEAN FROM NICARAGUA TO ACROSS CENTRAL CUBA INTO THE W ATLC.
AN UPPER TROUGH DIPS S OVER THE NE CARIBBEAN FROM HISPANIOLA TO
THE LEEWARD ISLANDS N OF 15N. A SECOND UPPER RIDGE IS OVER THE
SE CARIBBEAN COVERING THE S CARIBBEAN S OF 15N E OF 80W.
TROPICAL MOISTURE IS BEING DRAWN ACROSS THE SE CARIBBEAN DUE TO
THIS UPPER FLOW GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS WITHIN 90 NM OF LINE FROM THE PANAMA
CANAL ALONG 13N71W ACROSS THE WINDWARD ISLANDS NEAR SAINT
VINCENT. LIGHT TO MODERATE TRADE WINDS PREVAIL ACROSS THE BASIN
DUE TO THE BROAD PRESSURE GRADIENT. THESE TRADE WINDS WILL
CONTINUE OVER MOST OF THE CARIBBEAN THROUGH NEXT WEEK.

ATLANTIC OCEAN...
AN UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CENTRAL CUBA TO
BEYOND 32N74W. AFTERNOON SHOWERS/THUNDERSTORMS THAT DEVELOPED
OVER S FLORIDA ARE DIMINISHING BUT STILL PRODUCING ISOLATED
SHOWERS OFF THE E FLORIDA COAST. AN UPPER LEVEL TROUGH IS TO THE
E EXTENDING S TO OVER THE NE CARIBBEAN SUPPORTING A SURFACE
TROUGH THAT EXTENDS FROM 30N63W TO 25N61W AND IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM E AND 30
NM W OF THE SURFACE TROUGH AXIS. A BROAD UPPER RIDGE AXIS IS
OVER THE CENTRAL ATLC AND EXTENDS FROM 20N43W TO BEYOND 32N54W
GENERATING BROKEN/OVERCAST MULTILAYERED CLOUDS WITH ISOLATED
SHOWERS COVERING A BROAD AREA FROM 15N-30N BETWEEN 40W-58W. A
DEEP LAYERED LOW IS OVER THE E ATLC WITH THE UPPER LOW CENTERED
NEAR 30N26W AND A 1000 MB SURFACE LOW NEAR 28N28W. A DISSIPATING
OCCLUDED FRONT EXTENDS N OF THE LOW WITH A DISSIPATING COLD
FRONT ENTERING THE REGION NEAR 32N22W ALONG 23N22W TO 16N31W. A
RE-ENFORCING SURFACE TROUGH EXTENDS FROM 30N27W ALONG 27N25W
24N31W TO 27N39W. ISOLATED SHOWERS ARE N OF 28N BETWEEN 18W-30W.
A SURFACE TROUGH IS IN THE W TROPICAL ATLC JUST E OF THE LEEWARD
ISLANDS EXTENDING FROM 19N59W TO 14N57W WITH ISOLATED SHOWERS
WITHIN 120 NM E OF THE TROUGH AXIS. FRESH S FLOW WILL INCREASE
THIS EVENING OFF NE FLORIDA AHEAD OF COLD FRONT CURRENTLY IN THE
GULF OF MEXICO. THE FRONT WILL STALL FROM 31N69W TO THE FLORIDA
KEYS BY LATE SUN THEN BECOME DIFFUSE THROUGH SUN NIGHT. THE
SURFACE TROUGH WILL LINGER IN THE W TROPICAL ATLC THROUGH MON
THEN SHIFT TO THE N OF THE LEEWARD ISLANDS BY MIDWEEK.

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

$$
PAW






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