[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 160003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU SEP 15 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
2345 UTC.

...SPECIAL FEATURES...

TROPICAL STORM MARIA WAS UPGRADED TO HURRICANE STATUS AT 15/2100
UTC. MARIA IS CENTERED NEAR 36.8N 65.0W AT 16/0000 UTC OR ABOUT
915 MI...1475 KM SW OF CAPE RACE NEWFOUNDLAND MOVING N-NE AT 35
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. MAXIMUM
SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 34N-40N BETWEEN
61W-68W. THE HURRICANE IS EXPECTED TO TURN TO THE NORTHEAST AND
MOVE 45 KT OR FASTER ON FRIDAY AS IT GET CAUGHT IN VERY STRONG
SOUTHWESTERLY FLOW AHEAD OF A LARGE TROUGH OVER THE NORTHEASTERN
UNITED STATES. THE GLOBAL MODEL GUIDANCE CONTINUES TO SHIFT TO
THE NORTHWEST CLOSE TO NEWFOUNDLAND IN 24 HOURS.SEE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/
WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF MAURITANIA
NEAR 16N17W ALONG 12N21W TO A WEAK 1011 MB LOW NEAR 11N28W TO
ANOTHER 1011 MB LOW NEAR 9N35W TO NEAR 7N45W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 7N45W TO 8N56W. WHILE THE
ITCZ REMAINS INACTIVE...THE LARGE AND STRETCHED OUT MONSOON GYRE
IS PRODUCING WIDELY SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION FROM 3N-12N E OF 40W.

...DISCUSSION...

GULF OF MEXICO...
SATELLITE VISIBLE IMAGERY SHOWS MOSTLY CLEAR SKIES WITH A FEW
ISOLATED WEAK SHOWERS...MOVING WITH THE LIGHT ANTICYCLONIC FLOW
PRESENT ACROSS THE BASIN. WATER VAPOR IMAGERY SHOWS A LARGE
RIDGE OF HIGH PRESSURE CENTERED OVER EAST-CENTRAL MEXICO REGION
...PROVIDING MUCH OF THE GULF WITH MIDDLE TO UPPER LEVEL DRY AIR
AND SUBSIDENCE. AN COLD FRONT CURRENTLY ANALYZED INLAND ACROSS
THE GULF COASTAL PLAINS WILL INTRODUCE LIMITED CONVECTION AND A
MILDER AIRMASS TO THE NORTH-CENTRAL AND NE GULF WATERS THROUGH
EARLY SATURDAY.

CARIBBEAN SEA...
BROAD SURFACE CYCLONIC FLOW BETWEEN 72W-84W IS GENERATING
ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THIS AREA. WITHIN THIS
AREA OF WEAK SCATTERED CONVECTION...MOST OF THE ACTIVITY IS
FOCUSED S OF 15N WHERE THE MONSOON TROUGH IS ANALYZED OVER THE
FAR SW BASIN EXTENDING INLAND ACROSS COSTA RICO...PANAMA...AND
NORTHERN COLOMBIA. WATER VAPOR IMAGERY SHOWS A BROAD UPPER LEVEL
CYCLONIC CIRCULATION NE OF THE LESSER ANTILLES. THIS FEATURE IS
ENHANCING AN AREA OF SCATTERED MODERATE TO STRONG CONVECTION
ENTERING THE SE CARIBBEAN S OF 15N E OF 64W. AS THE SYSTEM
CONTINUES TO MOVE WESTWARD...A SURFACE TROUGH MAY DEVELOP OVER
THE SE AND S CENTRAL CARIBBEAN WATERS DURING THE NEXT 12-24
HOURS. THE REMAINDER OF  THE BASIN REMAINS UNDER FAIR WEATHER
CONDITIONS. COMPUTER MODELS SUGGEST THE MONSOON TROUGH OVER THE
SW BASIN WILL LIFT N OVER THE NEXT 24-36...HOURS WITH INCREASING
CONVECTION OVER THIS REGION AND INLAND PORTIONS OF CENTRAL
AMERICA.

ATLANTIC OCEAN...
HURRICANE MARIA IS TRACKING QUICKLY N-NE ACROSS THE HIGH SEAS
WATERS OF THE WESTERN ATLC THIS EVENING...INFLUENCED BY AN UPPER
LEVEL TROUGH TO ITS WEST. WATER VAPOR AND TOTAL PRECIPITABLE
WATER IMAGERY INDICATE A DEEP LAYER OF DRY AIR AND SUBSIDENCE W
OF 74W...MAINTAINING FAIR WEATHER CONDITIONS W OF MAINTAINING
MOSTLY FAIR SKIES W OF THIS LONGITUDE INCLUDING THE WATERS NEAR
THE BAHAMAS AND THE FLORIDA PENINSULA. AN OUTER BAND ASSOCIATED
TO MARIA EXTENDS WELL S INTO THE DISCUSSION AREA. THIS BAND IS
ANALYZED AS A LOW-LEVEL CONVERGENCE BOUNDARY/SURFACE TROUGH
ALONG 31N70W TO 25N73W GENERATING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITHIN 70 NM ON EITHER SIDE OF THE AXIS. FARTHER
SE...A BROAD UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED NEAR
20N57W. THIS FEATURE IS PROVIDING DIVERGENCE FLOW ALOFT TO THE
SE ENHANCING AN AREA OF SCATTERED MODERATE TO STRONG CONVECTION
FROM 10N-15N BETWEEN 50W-64W. THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE N
OF THE AREA.

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

$$

GARCIA




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