[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS THE SOUTHERN COAST OF GUINEA
NEAR 9N13W TO 4N19W. THE ITCZ BEGINS AT 4N19W AND CONTINUES
ALONG 3N31W 4N42W 2N52W. SCATTERED STRONG CONVECTION IS FROM EQ-
3N BETWEEN 12W-14W. SIMILAR ACTIVITY IS FROM 3N-5N BETWEEN 16W-
19W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL TROUGH COVERS THE MAJORITY OF THE GULF OF
MEXICO WITH AXIS ALONG 87W. THE UPPER TROUGH CONTINUES TO
SUPPORT A NOW STATIONARY FRONT THAT EXTENDS FROM SOUTH FLORIDA
NEAR 25N81W TO 25N86W 22N90W 18N90W...AS OF 0300 UTC. A SWATH OF
SHOWERS/ISOLATED THUNDERSTORMS IS NORTH OF THE FRONT ACROSS
CENTRAL FLORIDA FROM 26N-28N...WHICH CONTINUES WEST OF THE
FLORIDA PENINSULA TO 87W. POSSIBLE ISOLATED SHOWERS EXTEND UP TO
300 NM NORTH AND WEST OF THE AXIS ELSEWHERE. SCATTERED
SHOWERS/THUNDERSTORMS ALSO EXTEND SOUTH OF THE AXIS THROUGH THE
STRAITS OF FLORIDA TO NW CUBA. NORTHEAST WINDS OF 15-20 KT ARE
NORTH OF THE FRONTAL BOUNDARY BECOMING EASTERLY 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 CLEAR SKIES. THE WESTERN PORTION OF THE FRONT IS EXPECTED
TO SPLIT FROM THE MAIN FRONT OVER THE NEXT 24 HOURS AND WILL
DRIFT WEST AS EITHER A SURFACE TROUGH OR POSSIBLE WEAK SURFACE
LOW. 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 CENTRAL CUBA CONTINUING INTO
THE WEST ATLC. DRY AIR ALOFT ACROSS THIS AREA IS HELPING PROVIDE
FAIR CONDITIONS AT THE SURFACE. ONLY A FEW SHOWERS HAVE POPPED
UP OVER HONDURAS AND SOUTH OF EASTERN CUBA WITH A FEW POSSIBLE
SHOWERS OVER HISPANIOLA. HOWEVER...AN UPPER LEVEL TROUGH WITH
AXIS NEAR 67W IS PROVIDING SOME UPPER LEVEL MOISTURE ACROSS THE
FAR EASTERN CARIBBEAN ALONG WITH SOME DIFFLUENCE ALOFT
SUPPORTING SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS NORTH OF 13N
EAST OF 67W. 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 EASTERN CARIBBEAN AS THE UPPER TROUGH DRIFTS SLOWLY
EAST.

ATLANTIC OCEAN...
THE STATIONARY FRONT OVER THE SE GULF OF MEXICO EXTENDS INTO THE
WEST ATLC ALONG 25N80W TO 31N75W...AS OF 0300 UTC. SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS EXTEND UP TO 100 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 CENTRAL CUBA TO NEAR 31N70W. A LARGER
SCALE UPPER RIDGE IS CENTERED NEAR 30N59W...BUT A WEAK UPPER LOW
IS TO THE SOUTH NEAR 21N66W WITH AXIS CONTINUING INTO THE
CARIBBEAN. THE UPPER LOW/TROUGH IS SUPPORTING SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS FROM 13N-18N WEST OF 57W INTO THE
EASTERN CARIBBEAN. THE UPPER RIDGE TO THE NORTH SUPPORTS SURFACE
RIDGING ACROSS THE REMAINDER OF THE WEST ATLC ANCHORED BY A 1034
MB HIGH NEAR 42N45W. FARTHER EAST...AN UPPER LEVEL LOW NEAR
30N41W SUPPORTS BROAD SURFACE TROUGHING ALONG 30N35W TO 23N42W.
A DISSIPATING COLD FRONT IS TO THE EAST ALONG 32N35W TO 25N46W.
AN EARLIER ASCAT PASS INDICATES THAT A SURFACE LOW MAY BE
FORMING NEAR THE SURFACE TROUGH. ISOLATED SHOWERS ARE FROM 26N-
30N BETWEEN 32W-36W. AN UPPER LEVEL RIDGE ALONG 17W COVERS THE
REMAINDER OF THE EAST ATLC SUPPORTING A WEAK 1015 MB HIGH NEAR
24N32W.

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

$$
WALTON


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