[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN APR 21 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF SIERRA LEONE NEAR
8N13W TO 5N16W 3N21W. THE ITCZ BEGINS FROM 2N22W AND CONTINUES
ALONG EQ30W 1N40W EQ50W. SCATTERED MODERATE CONVECTION IS FROM
1S-5N BETWEEN 10W-30W. SIMILAR CONVECTION IS FROM 1S-6N BETWEEN
45W-53W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...THE PORTION OF THE FORMER STATIONARY FRONT OVER
THE SE GULF HAS DETACHED FROM THE REMAINDER FRONT AND DRIFTED
WESTWARD TOWARDS THE CENTRAL GULF AS A SURFACE TROUGH. THE
SURFACE TROUGH EXTENDS ALONG 27N89W 23N91W 18N91W.
RAINSHOWERS/ISOLATED THUNDERSTORMS ASSOCIATED TO THIS SURFACE
TROUGH ARE S OF 29N E OF 90W BEING ENHANCED BY MIDDLE-UPPER
LEVEL MOISTURE BEING ADVECTED BY W-NW WIND FLOW FROM THE E
PACIFIC. A PORTION OF THE REMAINDER STATIONARY FRONT EXTENDS
OVER THE FLORIDA KEYS ALONG 25N80W 24N82W GENERATING ISOLATED
SHOWERS AND THUNDERSTORMS. THE STATIONARY FRONT IS BEING
SUPPORTED BY A SHORT-WAVE TROUGH EXTENDING FROM S GEORGIA TO
FREEPORT IN THE BAHAMAS. WINDS RANGING FROM 5-15 KT SPREAD OVER
THE GULF S OF 27N...NE-E FLOW UP TO 20 KT ASSOCIATED TO SURFACE
RIDGING COVERS THE REMAINDER GULF N OF 27N. OVER THE COURSE OF
24 HOURS...THE SURFACE TROUGH IS EXPECTED TO STALL OVER THE
CENTRAL GULF WHICH WILL CONTINUE GENERATING RAINSHOWERS OVER THE
CENTRAL AND EASTERN GULF.

CARIBBEAN SEA...
AN UPPER LEVEL HIGH ANCHORED S OF MEXICO NEAR 15N100W EXTENDS TO
THE WESTERN CARIBBEAN AND A PORTION OF THE W ATLC. EXCEPT FOR
THE YUCATAN CHANNEL WHERE RAINSHOWERS ARE OCCURRING IN ASSOCIATION
TO THE SURFACE TROUGH OVER THE GULF...DRY AIR ALOFT EMBEDDED IN
THE RIDGE IS PROVIDING FOR THE MOST PART FAIR WEATHER CONDITIONS
ACROSS THE WESTERN...CENTRAL AND SOUTHERN CARIBBEAN. PATCHES OF
LOW LEVEL HUMIDITY IS PRODUCING RAINSHOWERS S OF CUBA BETWEEN
76W AND 81W AS WELL AS S OF LA HISPANIOLA BETWEEN 69W AND 72W.
OVER THE E CARIBBEAN...AN UPPER LEVEL TROUGH WITH AXIS NEAR 62W
IS PROVIDING SOME UPPER LEVEL MOISTURE THAT IS ENHANCING
RAINSHOWERS OVER THE LESSER ANTILLES. IN TERMS OF WIND...
TRADEWIND FLOW OF 5-15 KT SPREADS ACROSS MUCH OF THE BASIN
EXCEPT FOR THE EASTERN CARIBBEAN THAT WINDS CAN BE UP TO 20
KT. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
IN THE W ATLC...A STATIONARY FRONT EXTENDING ALONG 30N75W 28N78W
OVER THE FLORIDA KEYS TO 24N82W IS BEING SUPPORTED BY A SHORT-
WAVE TROUGH EXTENDING FROM S GEORGIA TO FREEPORT IN THE BAHAMAS.
STRONG ISOLATED SHOWERS AND THUNDERSTORMS ASSOCIATED TO THIS
FRONTAL BOUNDARY ARE FROM 24N-30N W OF 70W. SURFACE RIDGING FROM
A 1033 MB HIGH NEAR 42N39W SPREAD OVER THE ATLC W OF 50W. OVER
THE CENTRAL ATLC...AN UPPER LOW POSITIONED NEAR 28N40W IS
SUPPORTING A WEAK 1011 MB BROAD SURFACE LOW CENTERED NEAR
25N38W. A SURFACE TROUGH EXTENDS TOWARDS THE SW FROM THE LOW
CENTER TO NEAR 19N41W. SCATTERED SHOWERS ASSOCIATED TO THIS LOW
ARE FROM 26N-30N BETWEEN 35W-45W. AN UPPER LEVEL RIDGE ALONG 17W
COVERS THE REMAINDER OF THE EAST ATLC SUPPORTING A WEAK 1015 MB
HIGH NEAR 23N26W. OVER THE COURSE OF 24 HOURS...THE FRONT OVER
THE W ATLC IS EXPECTED TO STALL AND THEN LIFT BACK N OF THE
AREA.

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

$$
NR


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