[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 271817
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 27 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...SPECIAL FEATURE...

HURRICANE RINA HAS BEEN DOWNGRADED TO A TROPICAL STORM AT
27/1500 UTC. THE CENTER OF TROPICAL STORM RINA AT 27/1800 UTC
IS NEAR 19.5N 87.1W. RINA IS MOVING NORTHWARD/350 DEGREES
5 KT. RINA IS ABOUT 115 KM/70 MILES TO THE SOUTH OF COZUMEL IN
MEXICO...AND ABOUT 170 KM/105 MILES TO THE NORTHEAST OF CHETUMAL
IN QUINTANA ROO OF THE YUCATAN PENINSULA OF MEXICO. THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS ARE 60 KT WITH GUSTS TO 75 KT. PLEASE
READ THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/
WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.
UPPER LEVEL SOUTHERLY VERTICAL WIND SHEAR AND ENTRAINMENT OF
MIDDLE LEVEL TO UPPER LEVEL DRIER AIR HAVE COMBINED TO BEGIN
TO WEAKEN RINA A BIT. THE LOW LEVEL CENTER NOW IS EXPOSED
AT THE SOUTHERN EDGE OF A BURST OF DEEP CONVECTIVE PRECIPITATION.
NUMEROUS STRONG RAINSHOWERS ARE FROM 19N TO 20.5N BETWEEN 86W
AND 88W ALONG THE NORTHEASTERN COAST OF THE YUCATAN PENINSULA.
OTHER RAINSHOWERS COVER THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA/THE YUCATAN CHANNEL...AND THE SOUTHEASTERN GULF OF MEXICO
TO THE SOUTH OF 25N TO THE EAST OF 88W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REACHES THE AFRICA COAST NEAR 13N16W NEAR
SENEGAL AND GAMBIA. ISOLATED AND DISORGANIZED MODERATE
RAINSHOWERS COVER THE ATLANTIC OCEAN TO THE SOUTH OF 10N
TO THE EAST OF 35W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS MOVING THROUGH
EASTERN NEW MEXICO TOWARD THE TEXAS PANHANDLE. THIS CYCLONIC
CENTER SUPPORTS A COLD FRONT THAT IS MOVING THROUGH TEXAS TOWARD
THE GULF OF MEXICO. THE COLD FRONT IS FORECAST TO MOVE CLOSE TO
TROPICAL STORM RINA...WHEN BOTH FEATURES ARE IN THE SOUTHEASTERN
GULF OF MEXICO/THE YUCATAN CHANNEL AROUND 48 HOURS INTO THE
FUTURE. UPPER LEVEL SOUTHERLY WIND FLOW AND COMPARATIVELY DRIER
AIR IN THE WATER VAPOR IMAGERY COVER THE AREA TO THE WEST OF
90W...AND TO THE NORTH OF 28N TO THE EAST OF 90W. UPPER LEVEL
ANTICYCLONIC OUTFLOW FROM TROPICAL STORM RINA COVER THE AREA TO
THE EAST OF 90W. UPPER LEVEL MOISTURE IS TO THE SOUTH OF 28N TO
THE EAST OF 90W. A SURFACE RIDGE PASSES THROUGH 30N78W IN THE
ATLANTIC OCEAN TO 29N94W IN THE NORTHWESTERN CORNER OF THE AREA.

THE CARIBBEAN SEA...
TROPICAL STORM RINA AND ITS WEATHER AND CIRCULATION COVER THE
EXTREME NORTHWESTERN CORNER/THE YUCATAN CHANNEL. A SURFACE
TROUGH IS ALONG 80W FROM 13N TO 18N. SCATTERED TO NUMEROUS
STRONG RAINSHOWERS COVER THE WATERS FROM 14N TO 18N BETWEEN
77W AND 81W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG
RAINSHOWERS ARE ELSEWHERE FROM 10N TO 18N BETWEEN 72W AND
EASTERN NICARAGUA/EASTERN HONDURAS. THE MONSOON TROUGH PASSES
THROUGH 12N74W 11N80W BEYOND 10N IN COSTA RICA.
UPPER LEVEL CYCLONIC WIND FLOW COVERS THE EASTERN CARIBBEAN SEA
TO THE EAST OF 66W. THIS FLOW IS RELATED TO A TROUGH THAT
ORIGINATES IN THE ATLANTIC OCEAN NEAR 15N57W. ISOLATED MODERATE
RAINSHOWERS ARE FROM 8N TO 11N BETWEEN 54W AND 64W IN
NORTHEASTERN VENEZUELA. THE 24-HOUR RAINFALL TOTAL IN TRINIDAD
FOR THE TIME PERIOD ENDING AT 27/1200 UTC WAS 0.37 INCHES.

THE ATLANTIC OCEAN...
THE UPPER LEVEL ANTICYCLONIC OUTFLOW FROM TROPICAL STORM RINA
COVERS THE AREA TO THE WEST OF 75W. THE BROAD LARGE-SCALE WIND
FLOW BECOMES CYCLONIC TO THE EAST OF 75W...AND IT SPANS THE
ATLANTIC OCEAN TO THE NORTH OF 20N BETWEEN 40W AND 75W.
COMPARATIVELY DRIER AIR IN WATER VAPOR IMAGERY IS IN THIS AREA
ALSO. THE CYCLONIC FLOW WITH THE TROUGH SUPPORTS A COLD FRONT
THAT PASSES THROUGH 32N40W 26N50W TO 24N60W. A SURFACE TROUGH
CONTINUES FROM 24N60W TO 23N68W. RAINSHOWERS ARE POSSIBLE WITHIN
90 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N39W
26N50W 23N60W 23N70W. A SURFACE RIDGE PASSES THROUGH A 1019 MB
HIGH PRESSURE CENTER THAT IS NEAR 32N60W BEYOND 30N78W...INTO
THE GULF OF MEXICO. AN UPPER LEVEL TROUGH EXTENDS FROM A
CYCLONIC CIRCULATION CENTER THAT IS NEAR 20N38W...TO 15N42W...
TOWARD TRINIDAD AND NORTHEASTERN VENEZUELA. SCATTERED MODERATE
TO ISOLATED STRONG RAINSHOWERS ARE FROM 20N TO 21N BETWEEN 37W
AND 39W AROUND THE 20N38W CYCLONIC CENTER. RAINSHOWERS ARE
POSSIBLE ELSEWHERE FROM 16N TO 21N BETWEEN 28W AND 33W...FROM
10N TO 17N BETWEEN 36W AND 43W...AND FROM 8N TO 10N BETWEEN 43W
AND 48W. AN UPPER LEVEL TROUGH IS IN AFRICA PASSING THROUGH
MOROCCO. THE TROUGH SUPPORTS A DISSIPATING COLD FRONT THAT
REACHES THE CANARY ISLANDS. BROKEN TO OVERCAST CLOUDS COVER
THE CANARY ISLANDS.

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

$$
MT




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