[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 211838 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
235 PM EDT THU OCT 21 2010

*** AREA OF CONVECTION CORRECTED ON TROPICAL WAVE SECTION ***

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1745 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION NINETEEN BECAME TROPICAL STORM RICHARD AT
21/1500 UTC LOCATED NEAR 16.2N 80.4W. THIS LOCATION IS ABOUT 220
MI...355 KM SSE OF GRAND CAYMAN AND 205 MI...330 KM ENE OF CABO
GRACIAS A DIOS ON THE NICARAGUA AND HONDURAS BORDER. RICHARD IS
MOVING SE AT 5 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS
1006 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS
TO 45 KT. PLEASE READ THE FORECAST/ADVISORY LISTED UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC...AND THE INTERMEDIATE
PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC
FOR MORE DETAILS. SCATTERED MODERATE TO STRONG CONVECTION IS
FROM 13N-20N BETWEEN 77W-81W.

...TROPICAL WAVE...

A VIGOROUS TROPICAL WAVE IS OVER THE FAR EAST TROPICAL ATLANTIC
EMBEDDED IN THE ITCZ. WAVE AXIS IS ANALYZED FROM 16N20W TO 5N22W
MOVING W AT ABOUT 15 KT. THIS SYSTEM IS EMBEDDED IN A SURGE OF
DEEP LAYER MOISTURE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY.
BROAD CYCLONIC CURVATURE IS OBSERVED ALONG THE AXIS. SCATTERED
MODERATE TO ISOLATE STRONG CONVECTION IS FROM 5N-15N BETWEEN
18W-28W. EVEN THOUGH THIS IS HISTORICALLY NOT A FAVORABLE AREA
FOR TROPICAL CYCLONE FORMATION IN LATE OCTOBER...THIS SYSTEM IS
SHOWING SOME SIGNS OF ORGANIZATION...AND ENVIRONMENTAL
CONDITIONS ARE MARGINALLY CONDUCIVE FOR SOME ADDITIONAL
DEVELOPMENT TO OCCUR. LOCALLY HEAVY RAINFALL IS POSSIBLE OVER
THE SOUTHERN CAPE VERDE ISLANDS TODAY AND TONIGHT.

...THE ITCZ...

ITCZ AXIS IS ANALYZED WEST OF THE TROPICAL WAVE ALONG 8N23W
7N30W 10N38W...RESUMING NEAR 9N45W 6N51W TO THE COAST OF GUYANA
NEAR 7N58W. A SURFACE TROUGH IS N OF THE ITCZ EXTENDING FROM
18N40W THROUGH A 1012 MB LOW NEAR 13N42W TO 10N43W PRODUCING
CLUSTERS OF SCATTERED MODERATE CONVECTION FROM 14N-17N BETWEEN
35W-41W. ANOTHER BUT RATHER WEAK SURFACE TROUGH IS EMBEDDED IN
THE ITCZ EXTENDING FROM 10N30W TO 5N31W. CLUSTERS OF SCATTERED
WEAK CONVECTION ARE WITHIN 60 NM ON EITHER SIDE OF THE ITCZ AXIS
BETWEEN 27W AND 38W.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD MID-UPPER RIDGE CENTERED OVER THE FAR WESTERN GULF
CONTINUES TO DOMINATE THE AREA OF DISCUSSION...GIVING MOSTLY
CLEAR SKIES WITH FEW AREAS OF SCATTER LOW LEVEL STRATOCUMULUS
CLOUDS EMBEDDED IN THE LIGHT ANTICYCLONIC SFC FLOW. THIS FLOW IS
CENTERED AROUND A 1019 MB HIGH NEAR 27N93W. STRONG SUBSIDENCE
AND DRY AIR ALOFT WILL CONTINUE OVER THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
TROPICAL STORM RICHARD IS OVER THE WESTERN CARIBBEAN PRODUCING
MODERATE TO STRONG CONVECTION FROM 13N-20N BETWEEN 77W-81W. SEE
SPECIAL FEATURES ABOVE FOR MORE DETAILS. ELSEWHERE OUTSIDE THE
CONVECTION ASSOCIATED WITH RICHARD...DRY AND STABLE AIR ALOFT
COVERS MOST OF THE AREA OF DISCUSSION PROVIDING RELATIVELY FAIR
WEATHER CONDITIONS WITH A FEW AREAS OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS EMBEDDED IN THE TRADE WINDS. SE FLOW
ALOFT IS OBSERVED OVER THE EASTERN CARIBBEAN DRAWING SOME
LIMITED MID-UPPER LEVEL MOISTURE FROM NORTHERN S AMERICA. THIS
SCENARIO WILL CONTINUE OVER THE NEXT FEW DAYS ENHANCING AREAS OF
SCATTERED WEAK TO MODERATE CONVECTION ACROSS THE CENTRAL AND
EASTERN CARIBBEAN.

THE ATLANTIC OCEAN...
A BROAD MID-UPPER LEVEL TROUGH MOVES OFF THE NORTH AMERICA
SEABOARD...WHILE A BROAD UPPER LEVEL RIDGE IS IN THE CENTRAL
ATLC. THIS WEATHER SCENARIO IS DRAWING DEEP MOISTURE FROM THE SW
CARIBBEAN TO THE WESTERN ATLC...GENERATING AN AREA OF DEEP LAYER
CONFLUENCE ZONE MARKED BY A SURFACE TROUGH ANALYZED ALONG 32N65W
27N71W 25N76W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
WITHIN 160 NM EAST OF THE TROUGH AXIS. A WEAK UPPER LEVEL TROUGH
OVER THE EASTERN ATLC SUPPORTS A DISSIPATING COLD FRONT THAT
ENTERS THE DISCUSSION AREA NEAR 32N18W...EXTENDING TO 25N28W.
POSSIBLE ISOLATED CONVECTION IS WITHIN 30 NM ON EITHER SIDE OF
THE FRONT. THE REST OF THE AREA OF DISCUSSION N OF 18N REMAINS
UNDER FAIR WEATHER CONDITIONS SUPPORTED BY A DRY AND STABLE
UPPER ATMOSPHERE SEEN ON WATER VAPOR IMAGERY.

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

$$

GARCIA





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