[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI SEP 09 2011

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...
TROPICAL STORM NATE IS CENTERED NEAR 20.1N 92.9W AT 10/0000 UTC
OR ABOUT 225 MI...3600 KM ENE OF VERACRUZ MEXICO... AND 300
MI...480 KM ESE OF TUXPAN MEXICO. NATE IS STATIONARY. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 998MB. THE MAXIMUM SUSTAINED WIND
SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE THE LATEST
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER
MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADER MIATCMAT5/ WTNT25 KNHC FOR MORE DETAILS.
SCATTERED HEAVY SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 23N TO
INLAND OVER MEXICO AND THE YUCATAN PENINSULA BETWEEN 91W-97W.
ADDITIONAL STRENGTHENING TO HURRICANE STATUS IS POSSIBLE BEFORE
MAKING LANDFALL OVER MEXICO.

TROPICAL STORM MARIA IS CENTERED NEAR 15.0N 59.1W AT 10/0000 UTC
OR ABOUT 135 MI...215 KM N OF BARBADOS...OR ABOUT 185 MI...295
KM ESE OF GUADELOUPE MOVING NW AT 14 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 40
KT WITH GUSTS TO 50 KT. PLEASE SEE THE LATEST INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT4/ WTNT34 KNHC
AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER
MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO
STRONG CONVECTION IS FROM 12N-17N BETWEEN 54W-58W. ISOLATED
MODERATE CONVECTION IS ELSEWHERE FROM 10N-19N BETWEEN 50W-63W.
TROPICAL STORM WARNINGS HAVE BEEN ISSUED FOR NUMEROUS ISLANDS IN
THE LEEWARD ISLANDS.

HURRICANE KATIA IS CENTERED NEAR 40.6N 62.7W AT 09/2100 UTC OR
ABOUT 585 MI...940 KM N OF BERMUDA...OR ABOUT 280 MI...450 KM S
OF HALIFAX NOVA SCOTIA MOVING ENE AT 33 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE WAS 970 MB...WITH MAXIMUM SUSTAINED WIND SPEED
OF 70 KT WITH GUSTS TO 85 KT. PLEASE SEE THE LATEST INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND
THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/
WTNT22 KNHC FOR MORE DETAILS. KATIA IS FORECAST TO BECOME
POST-TROPICAL IN ABOUT 24 HOURS. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 39N-46N BETWEEN 56W-64W.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ANALYZED FROM
18N35W TO 6N40W MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN
AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY AND IS WELL DEFINED IN THE LOW LEVEL
CLOUD FIELD SATELLITE IMAGERY. SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE WITHIN 180 NM ON EITHER SIDE OF THE
WAVE AXIS.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ANALYZED FROM 19N75W
TO 11N77W MOVING W-NW NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN
AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY. THE SOUTHERN EXTENSION OF THE WAVE
AXIS IS INTERACTING WITH THE MONSOON TROUGH OVER THE SW
CARIBBEAN. WIDELY SCATTERED CONVECTION IS E OF THE WAVE AXIS
OVER HISPANIOLA AND THE CENTRAL CARIBBEAN FROM 13N-20N BETWEEN
68W-74W.

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

THE MONSOON TROUGH ENTERS THE TROPICAL E ATLANTIC AT THE
SOUTHERN COAST OF GUINEA-BISSAU NEAR 11N15W AND EXTENDS W TO
9N17W 11N25W. FURTHER W...A PORTION OF THE ITCZ HAS REDEVELOPED
FROM 9N43W TO 9N51W. ISOLATED MODERATE CONVECTION IS S OF THE
MONSOON TROUGH FROM 6N-9N BETWEEN 20W-26W.  SIMILAR CONVECTION
IS ASSOCIATED WITH THE ITCZ FROM 3N-12N BETWEEN 43W-52W.

...DISCUSSION...

GULF OF MEXICO...

THE PRIMARY CONCERN TONIGHT IS TROPICAL STORM NATE...SEE SPECIAL
FEATURES SECTION ABOVE. ELSEWHERE...AS OF 2100 UTC...A SURFACE
TROUGH IS OVER CENTRAL FLORIDA AND THE NE GULF OF MEXICO ALONG
29N81W 26N87W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
WITHIN 120 NM OF THE TROUGH. RADAR IMAGERY ALSO SHOWS SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OVER FLORIDA S OF 29N. FAIR
WEATHER IS NOTED OVER THE NW GULF AND TEXAS DUE TO UPPER LEVEL
DRY AIR SUBSIDENCE. IN THE NEXT 24 HOURS EXPECT NATE TO REMAIN
IN THE BAY OF CAMPECHE AND GRADUALLY INTENSIFY. ALSO EXPECT THE
TROUGH TO DRIFT N WITH SHOWERS.

CARIBBEAN SEA...
THE OUTER WIND BANDS OF MARIA IS PRODUCING CONVECTION OVER THE
EASTERN CARIBBEAN. SEE ABOVE. A TROPICAL WAVE IS ALSO OVER THE
CENTRAL CARIBBEAN. SEE ABOVE. ELSEWHERE...WIDELY SCATTERED
MODERATE CONVECTION IS NOTED INLAND OVER PORTIONS OF NW
VENEZUELA...AND N COLOMBIA. SIMILAR CONVECTION IS OVER CENTRAL
AMERICA FROM PANAMA TO S GUATEMALA. ISOLATED MODERATE CONVECTION
IS OVER THE HIGHER ELEVATIONS OF JAMAICA...AND CUBA. THE NW
CARIBBEAN IS UNDER UPPER LEVEL DRY AIR SUBSIDENCE BRINGING FAIR
WEATHER CONDITIONS N OF HONDURAS. 10-20 KT TRADEWINDS DOMINATE
THE CARIBBEAN WITH THE HIGHEST WINDS OVER THE E CARIBBEAN E OF
65W DUE TO THE APPROACH OF MARIA. EXPECT OVER THE NEXT 24 HOURS
FOR MARIA TO HAMPER THE E CARIBBEAN...AND THE TROPICAL WAVE
TO MOVE W TO THE W CARIBBEAN. ALSO EXPECT ADDITIONAL
CONVECTION TO BE OVER THE SW CARIBBEAN DUE TO THE MONSOON
TROUGH...AND OVER THE SW YUCATAN PENINSULA DUE TO NATE.

ATLANTIC OCEAN...
TROPICAL STORM MARIA...AND THE TROPICAL WAVE ARE THE
DOMINANT WEATHER PRODUCERS IN THE TROPICAL ATLANTIC. A
DISSIPATING STATIONARY FRONT IS OVER THE W ATLANTIC FROM 31N75W
TO 28N80W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE FRONT.
FURTHER E...A SURFACE TROUGH BROKE OFF FROM THE NORTHERN EXTENT
OF THE TROPICAL WAVE THAT IS PRESENTLY OVER THE CENTRAL
CARIBBEAN AND EXTENDS NEAR THE BAHAMAS FROM 27N72W TO 21N73W.
SCATTERED SHOWERS ARE WITHIN 120 NM E OF THE TROUGH AXIS. THE
TAIL END OF A COLD FRONT HAS ENTERED THE CENTRAL ATLANTIC NEAR
32N30W TO 30N49W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE
FRONT. A 1020 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC NEAR
33N52W. ANOTHER 1018 MB HIGH IS OVER THE E ATLANTIC NEAR
27N31W.

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

$$
FORMOSA




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