[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 022336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 02 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURES...

POST-TROPICAL CYCLONE KIRK IS CENTERED NEAR 49.7N 32.6W AT
02/2100 UTC OR ABOUT 840 NM ENE OF CAPE RACE NEWFOUNDLAND...AND
ABOUT 740 NM NNW OF THE AZORES MOVING NE AT 41 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND
SPEED IS 45 KT WITH GUSTS TO 55 KT. NO DEEP CONVECTION IS
ASSOCIATED WITH THE SYSTEM. SEE LATEST NHC FORECAST/ ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

TROPICAL STORM LESLIE IS CENTERED NEAR 22.2N 61.4W AT 02/2100
UTC OR ABOUT 320 NM N OF THE LEEWARD ISLANDS MOVING NW AT 9 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED
WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. NUMEROUS STRONG
CONVECTION IS FROM 19N-23N BETWEEN 58W-63W. SCATTERED MODERATE
CONVECTION IS ELSEWHERE FROM 17N-23N BETWEEN 57W-64W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 20N29W TO 13N32W MOVING W NEAR 12 KT. THE
WAVE LIES ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. AN EXTREMELY DRY
AIR MASS TO THE N AND W OF THE WAVE IS LIMITING ANY DEEP
CONVECTION NEAR THE AXIS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
MAURITANIA AT 18N16W CONTINUING TO SOUTH OF THE TROPICAL WAVE IN
THE E ATLC AT 13N32W AND ENDING NEAR 9N47W. THE ITCZ BEGINS AT
9N47W AND CONTINUES TO 10N60W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 11N-14N BETWEEN 17W-23W. SIMILAR
ACTIVITY IS FROM 6N-8N BETWEEN 43W-52W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO
EXTENDING FROM A 1020 MB HIGH CENTER SOUTH OF MISSISSIPPI AT
28N88W. THIS PATTERN IS PROVIDING MAINLY LIGHT E-SE FLOW ACROSS
THE BASIN. THE SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL
RIDGE COVERING MUCH OF THE SOUTHERN CONUS AND PROVIDING DRY AIR
ALOFT IN MAINLY NE FLOW. THIS COMBINATION OF DRY AIR ALOFT AND
SURFACE RIDGING IS GENERATING MOSTLY FAIR CONDITIONS ACROSS THE
BASIN. A FEW ISOLATED SHOWERS/THUNDERSTORMS DOT THE NORTHERN
GULF COAST...FLORIDA...AND THE YUCATAN PENINSULA. SURFACE
RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN FOR THE NEXT
COUPLE OF DAYS.

THE CARIBBEAN SEA...
MOSTLY FAIR WEATHER COVERS THE CARIBBEAN TONIGHT DUE TO
WIDESPREAD DRY AIR ALOFT MOVING OVER THE BASIN AROUND AN UPPER
LEVEL TROUGH OVER THE WESTERN CARIBBEAN...AND AN UPPER LEVEL
RIDGE OVER THE EASTERN CARIBBEAN. AFTERNOON CONVECTION OVER CUBA
IS BEGINNING TO DIE DOWN WITH SOME SHOWERS/THUNDERSTORMS STILL
REMAINING OVER THE ISLAND. SHOWERS/THUNDERSTORMS ARE ALSO ACROSS
PORTIONS OF NICARAGUA AND THE MAJORITY OF COSTA RICA AND PANAMA
ASSOCIATED WITH THE E PAC MONSOON TROUGH THAT EXTENDS THROUGH
BOTH COUNTRIES TO A 1009 MB LOW OVER NORTHERN COLOMBIA. SOME
POSSIBLE ISOLATED SHOWERS ARE ALSO OVER THE NORTHERN LEEWARD
ISLANDS DUE TO T.S. LESLIE TO THE NORTH. TRADEWIND FLOW OF 10-15
KT IS ACROSS THE MAJORITY OF THE BASIN REACHING 20 KTS NEAR THE
COAST OF COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
AN UPPER LEVEL LOW IS SPINNING OVER THE NW BAHAMAS NEAR 25N77W
WITH AXIS EXTENDING INTO THE THE WESTERN CARIBBEAN. WHILE MOSTLY
DRY AIR ACCOMPANIES THE UPPER LOW...A FEW ISOLATED
SHOWERS/THUNDERSTORMS HAVE STILL POPPED UP FROM 24N-26N BETWEEN
75W-79W. TROPICAL STORM LESLIE IS PRODUCING A LARGE AREA OF
STRONG SHOWERS/THUNDERSTORMS IN THE CENTRAL ATLC N OF THE
LEEWARD ISLANDS. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. AN
UPPER LEVEL RIDGE IS CENTERED JUST W OF THE STORM CENTER...AND
SUPPORTS A WEAK 1021 MB SURFACE HIGH NEAR 27N50W. HOWEVER...AN
UPPER LEVEL SHORTWAVE TROUGH MOVING THROUGH A LONGWAVE TROUGH TO
THE NORTH IS HELPING SUPPORT SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 23N-26N BETWEEN 50W-52W...AND FROM 25N-29N
BETWEEN 52W-57W. AN UPPER LEVEL LOW TO THE E CENTERED NEAR
27N39W SUPPORTS A 1015 MB SURFACE LOW AT 26N40W. A SURFACE
TROUGH EXTENDS THROUGH THE LOW CENTER FROM 32N40W TO 22N38W.
ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS
N OF 25N. THE REMAINDER OF THE E ATLC IS DOMINATED BY SURFACE
RIDGING EXTENDING FROM A 1027 MB AZORES HIGH. THE HIGH IS
SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED BOTH N OF THE AZORES
NEAR 46N23W...AND SOUTH OF THE AZORES CENTERED NEAR 21N24W. THE
LAST VISIBLE SATELLITE IMAGES OF THE DAY ALONG WITH GOES-R
ENHANCEMENT IMAGERY INDICATE A LARGE ARE OF DUST EXTENDS FROM
THE COAST OF AFRICA AROUND THE WAVE AND MONSOON TROUGH IN THE E
ATLC TO NEAR 50W. THIS DRY AIR MASS IS HELPING SUPPORT FAIR
WEATHER IN THE AREA.

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

$$
WALTON




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