[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN APR 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE SOUTHERN COAST OF LIBERIA
NEAR 5N8W WESTWARD ALONG 1S20W EQ30W 2S40W INTO BRAZIL NEAR
4S47W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
WITHIN 170 NM EITHER SIDE OF THE ITCZ W OF 17W. CLUSTERS OF
SIMILAR CONVECTION ARE DOTTING THE AREA S OF THE ITCZ FROM
4S-10S BETWEEN 5W-30W.

...DISCUSSION...

GULF OF MEXICO...
THE MAJORITY OF THE GULF OF MEXICO IS EXPERIENCING FAIR WEATHER
CONDITIONS UNDER THE INFLUENCE OF DRY AIR ALOFT WITH A FEW HIGH
LEVEL CLODS MOVING ACROSS THE AREA. A DEEP LAYER TROUGH MOVES
ACROSS THE FAR EASTERN CONUS SUPPORTING A COLD FRONT THAT ENTERS
THE AREA THROUGH THE FLORIDA PENINSULA NEAR CAPE CORAL AND
EXTENDS SW TO 24N86W AS IT TRANSITIONS TO A WEAK STATIONARY
FRONT. ONLY A WEAK CLOUD BAND ALONG WITH A WIND SHIFT AND LOWER
DEW POINTS DEFINE THIS FRONTAL SYSTEM. MARINE OBS INDICATE 5-15
KT ANTI-CYCLONIC FLOW BEHIND THE FRONT. THE FRONT WILL CONTINUE
TO WEAKEN AS IT LOOSES MOMENTUM ACROSS THE SE GULF IN THE
MORNING HOURS. SURFACE RIDGE BEHIND THE FRONT WILL CONTINUE TO
BUILD ACROSS THE GULF...ALLOWING FRESH SE FLOW OVER THE W GULF
LATER TODAY. SE WINDS WILL INCREASE ACROSS THE ENTIRE GULF
EARLY NEXT WEEK AHEAD OF AN APPROACHING TROUGH MOVING THROUGH
THE SOUTHERN PLAINS.

CARIBBEAN SEA...
MAINLY DRY AIR ALOFT AND STRONG SUBSIDENCE IS ACROSS THE
CARIBBEAN SEA THIS MORNING...PROVIDING MOSTLY FAIR WEATHER
CONDITIONS ACROSS THE BASIN. AN UPPER RIDGE EXTENDS FROM THE E
PACIFIC REGION ACROSS THE W CARIBBEAN FROM NICARAGUA TO ACROSS
CENTRAL CUBA INTO THE W ATLC. STRONG SUBSIDENCE ASSOCIATED WITH
AN UPPER TROUGH DIPS S OVER THE NE CARIBBEAN ACROSS HISPANIOLA
AND PUERTO RICO TO THE LEEWARD ISLANDS. HIGH LEVEL CLOUDS ARE
BEING DRAWN ACROSS THE S CARIBBEAN DUE TO UPPER ANTI-CYCLONIC
FLOW AROUND AN UPPER RIDGE CENTERED IN NORTHERN S AMERICA . AT
SURFACE...MARINE OBS INDICATE MODERATE TO FRESH ENE WIND FLOW
ACROSS THE AREA. STRONGER TRADES ARE TURNING ACROSS THE COAST OF
COLOMBIA...GENERATING SCATTERED SHOWERS ALONG THE COAST OF
COLOMBIA BETWEEN 72W-77W. FAIR WEATHER IS EXPECTED TO REMAIN
ACROSS THE REST OF THE BASIN OVER THE NEXT 24 HOURS. LIGHT TO
MODERATE TRADE WINDS WILL 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...
A DEEP LAYER TROUGH MOVES OFF THE EASTERN CONUS SUPPORTING A
VIGOROUS COLD FRONT EXTENDING ACROSS THE WESTERN ATLC ALONG
32N75W TO THE FLORIDA COAST NEAR 27N80W. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE IN THE VICINITY OF THE FRONT N OF
29N. THIS FRONT WILL CONTINUE TO MOVE EASTWARD WITH CONVECTION
OVER TH NEXT 24 HOURS. FARTHER E INTO THE CENTRAL ATLC...AN
UPPER LEVEL TROUGH EXTENDS S TO OVER THE NE CARIBBEAN SUPPORTING
A BROAD AREA OF SCATTERED WEAK TO ISOLATED MODERATE CONVECTION
FROM 21N-30N BETWEEN 47W-58W. COMPUTER MODELS SUGGEST THIS AREA
OF CONVECTION WILL LINGER FOR AT LEAST THE NEXT 24 HOURS. THE
UPPER LEVEL TROUGH ALSO SUPPORTS TWO SURFACE TROUGHS ANALYZED W
AND SSW FROM THE AREA OF CONVECTION. THE FIRST ONE IS ANALYZED
FROM 29N62W TO 25N60W. THE SECOND ONE IS ANALYZED FROM 23N53W TO
14N54W. A DEEP LAYERED LOW IS OVER THE FAR E ATLC WITH THE UPPER
LOW CENTERED NEAR 32N22W AND A 1003 MB SURFACE LOW NEAR 30N23W.
A DISSIPATING COLD FRONT IS E OF THE LOW FROM 33N17W TO 25N19W.
A RE-ENFORCING SURFACE TROUGH EXTENDS ALONG 31N21W 26N21W
23N24W. THESE TWO BOUNDARIES ALONG WITH THE LOW LEVEL CENTER ARE
GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 27N
BETWEEN 15W-26W. THIS LOW PRESSURE SYSTEM IS EXPECTED TO
CONTINUE TO DRIFT E AND WEAKEN OVER THE NEXT 24 HOURS.

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

$$

GARCIA




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