[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON OCT 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION EIGHTEEN WAS UPGRADED TO TROPICAL STORM RINA
AT 24/0600 UTC AND IS CENTERED NEAR 16.5N 82.2W OR ABOUT 90 NM
NE OF CABO GRACIAS A DIOS ON NICARAGUA/HONDURAS BORDER AND ABOUT
180 NM S-SW OF GRAND CAYMAN MOVING N-NW AT 6 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND
SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE 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.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN A 60/75 NM RADIUS
OF 18N82W WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION COVERING THE REMAINDER OF THE AREA 15N-22N BETWEEN
77W-85W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 12N16W CONTINUING ALONG 11N20W 12N29W TO 11N36W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-9N BETWEEN
40W-45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND
AND WITHIN 60 NM ALONG THE COAST OF SOUTH AMERICA BETWEEN
53W-58W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION COVERS THE REMAINDER OF THE AREA FROM 7N-12N BETWEEN
31W-48W WITH SMALL CLUSTERS OF SIMILAR CONVECTION FROM 2N-7N
BETWEEN 10W-18W. A 1011 MB LOW IS IN THE CENTRAL TROPICAL ATLC
NEAR 14N42W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION
FROM 12N-15N BETWEEN 42W-44W. A 1010 MB LOW IS E OF THE WINDWARD
ISLANDS NEAR 12N56W WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION FROM 8N-11N BETWEEN 52W-55W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH CONTINUES TO DIG FURTHER S OVER THE GULF TO 23N
SUPPORTING A FRONTAL BOUNDARY THAT REMAINS INLAND STRETCHING
FROM MISSISSIPPI TO TEXAS AND NEAR ZONAL WESTERLY FLOW ALOFT
ACROSS THE S GULF. STRONG SUBSIDENCE AND DRY STABLE AIR
CONTINUES TO DOMINATE THE GULF LIMITING ANY SHOWER ACTIVITY.
HOWEVER...SOME LOW LEVEL CLOUDS AND ISOLATED SHOWERS ARE OVER S
LOUISIANA MOVING INTO THE GULF WATERS WITHIN 45 NM ALONG THE
COAST. OUTFLOW FROM THE UPPER HIGH ASSOCIATED WITH TROPICAL
STORM RINA IS MOVING OVER THE FAR SE GULF AND THE STRAITS OF
FLORIDA WITH SCATTERED SHOWERS S OF 26N E OF 84W LEAVING THE
REMAINDER OF THE GULF UNDER CLEAR SKIES AGAIN TONIGHT. WEAK
SURFACE RIDGE IS OVER THE N GULF THAT WILL REMAIN THROUGH WED
NIGHT THEN WEAKEN THU IN ADVANCE OF A COLD FRONT MOVING OFF THE
TEXAS COAST AND EXTENDING FROM FLORIDA BIG BEND TO BAY OF
CAMPECHE FRI AND MOVE OUT OF THE GULF BY SAT.

CARIBBEAN SEA...
THE PRIMARY CONCERN TONIGHT IS TROPICAL STORM RINA IN THE NW
CARIBBEAN. SEE SPECIAL FEATURES SECTION ABOVE. THE UPPER HIGH
ASSOCIATED WITH RINA COVERS THE NW CARIBBEAN AND HAS GOOD
OUTFLOW IN ALL BUT THE S QUADRANT. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE INLAND AND WITHIN 75 NM ALONG THE COAST OF
COLOMBIA BETWEEN 72W-75W...FROM PANAMA TO S NICARAGUA S OF 12N W
OF 80W...AND HAITI INTO THE GULF OF GONAVE. A BROAD LOW/MID
LEVEL TROUGH IS IN THE W TROPICAL ATLC INTO THE E CARIBBEAN
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 17N E
OF 65W ACROSS THE LESSER ANTILLES. THIS IS LEAVING THE REMAINDER
OF THE CARIBBEAN UNDER CLEAR SKIES TONIGHT. TROPICAL STORM RINA
IS EXPECTED TO REMAIN IN THE NW CARIBBEAN REACHING THE YUCATAN
COAST EARLY THIS WEEKEND. THE BROAD TROUGH OVER THE W TROPICAL
ATLC/E CARIBBEAN WILL CONTINUE MOVING W TO THE S CENTRAL
CARIBBEAN WED AND MERGE INTO THE MONSOON TROUGH IN THE SW
CARIBBEAN THU AND FRI.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE GULF OF MEXICO IS MOVING INTO THE W
ATLC WHILE A SURFACE TROUGH REMAINS ACROSS THE AREA EXTENDING
FROM A STATIONARY BOUNDARY THROUGH 32N69W ALONG 29N76W ACROSS
THE GRAND BAHAMA ISLAND TO 25N79W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE FROM 28N-31N BETWEEN 73W-78W. OUTFLOW FROM THE
UPPER HIGH ASSOCIATED WITH TROPICAL STORM RINA IS MOVING OVER
THE STRAITS OF FLORIDA AND SW ATLC GENERATING SCATTERED SHOWERS
S OF 27N W OF 77W TO OVER S FLORIDA AND THROUGH THE STRAITS OF
FLORIDA. A BROAD LOW/MID LEVEL TROUGH IS OVER THE W TROPICAL
ATLC INTO THE E CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 10N-17N W OF 51W ACROSS THE LESSER ANTILLES.
A BROAD SURFACE RIDGE DOMINATES THE ATLC N OF 20N E OF 65W
ANCHORED BY A 1026 MB HIGH NEAR 34N43W. THE E/W UPPER RIDGE OVER
THE TROPICAL ATLC IS S OF 20N E OF 38W GENERATING SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 10N-17N BETWEEN
23W-40W. A COLD FRONT WILL MOVE INTO THE W ATLC EARLY MON AND
WILL ABSORB THE SURFACE TROUGH. THE COLD FRONT WILL REACH FROM
BERMUDA TO THE SE BAHAMAS EARLY TUE AND MOVE INTO THE CENTRAL
ATLC WED. AN E/W RIDGE WILL BUILD ALONG THE N PERIPHERY WED
NIGHT AND THU THEN WEAKEN FRI ALLOWING A SECOND COLD FRONT TO
MOVE OFF THE GEORGIA COAST FRI NIGHT.

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

$$
PAW





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