[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201150
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF SIERRA LEONE NEAR
8N13W AND CONTINUES TO 4N18W. THE ITCZ BEGINS AT 4N18W AND
CONTINUES ALONG 3N36W 2N53W. SCATTERED STRONG CONVECTION IS FROM
3N-6N BETWEEN 11W-20W...AND FROM 2N-4N BETWEEN 22W-26W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-5N
BETWEEN 40W-42W...AND FROM 3N-5N BETWEEN 46W-52W.



...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH COVERING MUCH OF THE
EASTERN CONUS AND THE NORTHERN GULF OF MEXICO SUPPORTS A COLD
FRONT THAT CONTINUES TO SWEEP ACROSS THE BASIN. IT CURRENTLY
EXTENDS FROM CENTRAL FLORIDA NEAR 29N80W TO JUST WEST OF THE
YUCATAN PENINSULA ALONG 24N88W 18N91W...AS OF 0900 UTC.
SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS EXTEND UP TO 200 NM
WEST OF THE AXIS. A FEW WIDELY ISOLATED SHOWERS ARE ALSO AHEAD
OF THE FRONT ACROSS PORTIONS OF FLORIDA WITH MORE OFF THE EAST
COAST OF FLORIDA. STRONG NORTHERLY WINDS ARE WEST OF THE AXIS
REACHING UP TO 25 KT. THE GALE FORCE WINDS PREVIOUSLY IN THE SW
GULF HAVE NOW DROPPED BELOW GALE FORCE. A FEW 30 KT WINDS MAY
STILL BE PRESENT IN THE SW PORTION WEST OF THE FRONT. A SURFACE
TROUGH IS ALSO ALONG THE YUCATAN PENINSULA OUT AHEAD OF THE
FRONT SUPPORTING HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE
PENINSULA AND GUATEMALA. AN UPPER LEVEL RIDGE COVERS THE
REMAINDER OF THE SOUTHERN GULF OF MEXICO EXTENDING FROM A CENTER
SOUTH OF MEXICO WITH AXIS CONTINUING ACROSS THE YUCATAN
PENINSULA TOWARDS THE NW BAHAMAS. SURFACE RIDGING IS ALSO
BUILDING IN BEHIND THE FRONT CURRENTLY CENTERED OVER TEXAS AND
MEXICO. CLEAR SKIES ARE ALREADY BEING NOTED OVER THE FAR NW
CORNER OF THE AREA. THE FRONT IS EXPECTED TO CONTINUE MOVING SE
OVER THE NEXT 24 HOURS BEFORE STALLING OVER SOUTH FLORIDA.

CARIBBEAN SEA...
THE UPPER LEVEL RIDGE COVERING THE SOUTHERN
GULF ALSO SPREADS OVER THE NW CARIBBEAN ACCOMPANIED BY DRY AIR
ALOFT...WHICH IS PROVIDING FAIR SURFACE CONDITIONS ACROSS MUCH
OF THE AREA. AN UPPER LEVEL TROUGH COVERS THE REMAINDER OF THE
CARIBBEAN WITH AXIS EXTENDING FROM HISPANIOLA TO NICARAGUA.
MOIST SOUTHWESTERLY FLOW ALOFT COVERS THE EASTERN PORTIONS OF
THE BASIN. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE OVER THE
NE CARIBBEAN FROM 17N-18N BETWEEN 63W-72W. TRADEWIND FLOW OF
MAINLY 20 KT IS ACROSS THE CENTRAL AND EASTERN CARIBBEAN. EXPECT
LITTLE CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING OVER THE SE GULF OF MEXICO
CONTINUES IN THE FAR WESTERN ATLC PROVIDING MOSTLY FAIR
CONDITIONS ACROSS THIS AREA. HOWEVER...THE COLD FRONT OVER THE
GULF OF MEXICO IS BEGINNING TO EMERGE INTO THE WEST ATLC
CURRENTLY ALONG 32N78W TO 29N81W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS EXTEND UP TO 90 NM EAST OF THE FRONT...AND
CONTINUE OVER FLORIDA. THE REMAINDER OF BOTH THE WEST AND
CENTRAL ATLC ARE DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY
A 1034 MB HIGH NEAR 41N47W. THE RIDGE IS SUPPORTED BY AN UPPER
LEVEL RIDGE CENTERED NEAR 32N58W. A WEAK UPPER LEVEL TROUGH IS
CENTERED TO THE SOUTH OF THE UPPER RIDGE FROM NEAR 21N68W TO
EASTERN HISPANIOLA AND INTO THE CARIBBEAN. FARTHER EAST...A
NARROW UPPER TROUGH IS ALONG 30N37W TO 21N49W. THE UPPER TROUGH
SUPPORTS A SURFACE TROUGH THAT EXTENDS ALONG 31N36W TO 25N41W.
ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE AXIS. A
SECOND SURFACE TROUGH EXTENDS FROM JUST SOUTH OF THE CANARY
ISLANDS INTO NW AFRICA ALONG 30N20W TO 22N13W. NO SHOWERS ARE
NEAR THIS AXIS. THE REMAINDER OF THE BASIN IS COVERED BY A BROAD
UPPER RIDGE WITH AXIS ALONG 14W.

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

$$
WALTON

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