[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211144
TWDAT

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

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE COAST OF GUINEA NEAR
10N14W TO 2N23W. THE ITCZ BEGINS FROM 2N23W AND CONTINUES ALONG
EQ39W 1S46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 1N-6N BETWEEN 11W-23W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH COVERS THE MAJORITY OF THE GULF OF
MEXICO WITH AXIS SHIFTING EAST AND CURRENTLY EXTENDING ALONG
83W. THE UPPER TROUGH CONTINUES TO SUPPORT A STATIONARY FRONT
THAT EXTENDS FROM SOUTH FLORIDA NEAR 26N80W TO 24N89W
19N91W...AS OF 0900 UTC. MOST OF THE SHOWER ACTIVITY OVER
FLORIDA HAS MOVED EAST OF THE BASIN EXCEPT FOR SOME STRONG
SHOWERS NEAR CAPE CANAVERAL. STRONG SHOWERS/ISOLATED
THUNDERSTORMS ARE ALSO SOUTH OF THE AXIS IN THE STRAITS OF
FLORIDA. ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS EXTEND UP
TO 250 NM NORTH AND WEST OF THE AXIS ELSEWHERE. NORTHEAST TO
EAST WINDS OF 15-20 KT ARE NORTH OF THE FRONTAL BOUNDARY
BECOMING SOUTHEASTERLY ACROSS THE WESTERN GULF AS THEY WRAP
AROUND THE SOUTHERN EDGE OF A SURFACE RIDGE COVERING MUCH OF THE
EASTERN CONUS. DRY AIR ALOFT AROUND THE WEST SIDE OF THE UPPER
TROUGH IS KEEPING THE FAR NW GULF UNDER FAIR CONDITIONS. THE
WESTERN PORTION OF THE FRONT IS EXPECTED TO SPLIT FROM THE MAIN
FRONT OVER THE NEXT 24 HOURS AND WILL DRIFT WEST AS A SURFACE
TROUGH. SURFACE RIDGING WILL DOMINATE THE REMAINDER OF THE BASIN
FOR THE NEXT SEVERAL DAYS. SHOWERS AND THUNDERSTORMS WILL LIKELY
REMAIN ACROSS THE EASTERN GULF AND FLORIDA THROUGH AT LEAST
MONDAY.

CARIBBEAN SEA...
UPPER LEVEL RIDGING COVERS THE WESTERN CARIBBEAN EXTENDING FROM
SOUTH OF MEXICO ACROSS GUATEMALA TO EASTERN CUBA CONTINUING INTO
THE WEST ATLC. DRY AIR ALOFT ACROSS THIS AREA IS HELPING PROVIDE
FAIR CONDITIONS AT THE SURFACE. ONLY A FEW SHOWERS CONTINUE OVER
HONDURAS AND SOUTH OF CUBA. HOWEVER...AN UPPER LEVEL TROUGH WITH
AXIS NEAR 65W IS PROVIDING SOME UPPER LEVEL MOISTURE ACROSS THE
FAR EASTERN CARIBBEAN ALONG WITH SOME DIFFLUENCE ALOFT
SUPPORTING SCATTERED SHOWERS FROM 14N-17N EAST OF 71W. TRADEWIND
FLOW OF 15-20 KT SPREADS ACROSS MUCH OF THE CENTRAL AND EASTERN
CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS.
MOISTURE AND LIKELY SHOWERS WILL REMAIN OVER THE NORTHEAST
CARIBBEAN.

ATLANTIC OCEAN...
THE STATIONARY FRONT OVER THE SE GULF OF MEXICO EXTENDS INTO THE
WEST ATLC ALONG 26N80W TO 32N74W...AS OF 0900 UTC. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS EXTEND UP TO 120 NM EITHER SIDE
OF THE AXIS. THE SYSTEM IS SUPPORTED BY A BROAD UPPER TROUGH
COVERING MUCH OF THE EASTERN CONUS. AN UPPER LEVEL RIDGE IS TO
THE EAST EXTENDING FROM EASTERN CUBA TO NEAR 31N68W. A LARGER
SCALE UPPER RIDGE IS CENTERED NEAR 30N58W SUPPORTING A SURFACE
RIDGE ANCHORED NEAR 43N42W. A WEAK UPPER LOW IS TO THE SOUTH OF
THE UPPER RIDGE NEAR 21N65W WITH AXIS CONTINUING INTO THE
CARIBBEAN. THE UPPER LOW/TROUGH IS SUPPORTING SCATTERED SHOWERS
FROM 13N-17N WEST OF 56W INTO THE EASTERN CARIBBEAN. FARTHER
EAST...AN UPPER LEVEL LOW NEAR 29N42W SUPPORTS A WEAK 1011 MB
BROAD SURFACE LOW CENTERED NEAR 27N37W. A SURFACE TROUGH EXTENDS
TOWARDS THE SW FROM THE LOW CENTER TO NEAR 20N42W. ISOLATED
SHOWERS ARE TO THE NE FROM 28N-30N BETWEEN 31W-37W...AND TO THE
WEST FROM 23N-30N BETWEEN 39W-42W. AN UPPER LEVEL RIDGE ALONG
16W COVERS THE REMAINDER OF THE EAST ATLC SUPPORTING A WEAK 1015
MB HIGH NEAR 20N31W.

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

$$
WALTON


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