[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 23 2010

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 1750 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM RICHARD AT 23/1800 UTC IS NEAR
16.0N 83.8W. RICHARD IS MOVING WESTWARD 7 KT. THE ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND
SPEEDS ARE 50 KT WITH GUSTS TO 60 KT. THE STORM IS ABOUT 80
MI...130 KM NNW OF CABO GRACIAS A DIOS ON THE NICARAGUA AND
HONDURAS BORDER...AND ABOUT 185 MI...295 KM E OF ISLA ROATAN
HONDURAS.  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. MODERATE TO STRONG CONVECTION FROM 14N-22N
BETWEEN 75W-86W. ANOTHER AREA OF MODERATE TO STRONG CONVECTION
IS OVER THE FAR SOUTHWEST BASIN S OF 14N WEST OF 75W...
ASSOCIATED WITH THE LARGE CYCLONIC FLOW FROM RICHARD DRAWING
DEEP MOISTURE FORM THE FAR EAST TROPICAL PACIFIC ITCZ TO THE
SOUTHWEST CARIBBEAN. ENVIRONMENTAL CONDITIONS ARE BECOMING MORE
CONDUCTIVE TO STRENGTHENING OVER THE NEXT 24 HOURS.

...TROPICAL WAVE...

TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS. THE WAVE AXIS
IS ANALYZED ALONG 19N26W TO A SURFACE LOW NEAR 17N27W TO 12N29W
MOVING NW AT ABOUT 8-13 KT. THIS SYSTEM IS EMBEDDED IN AN AREA
OF DEEP LAYER MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. A BROAD AREA OF WEAK CYCLONIC CURVATURE IS OBSERVED
ALONG THE AXIS. SCATTERED MODERATE TO ISOLATE STRONG CONVECTION
IS FROM 16N-21N BETWEEN 21W-28W. THE POSSIBILITY THAT THIS
FEATURE MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 24 HOURS
IS SIGNIFICANTLY REDUCED AS UPPER LEVEL WINDS ARE BECOMING LESS
CONDUCIVE TO SUPPORT DEVELOPMENT. HOWEVER...LOCALLY HEAVY
RAINFALL AND STRONG GUSTY WINDS WILL STILL BE POSSIBLE OVER THE
CAPE VERDE ISLANDS THROUGH LATER THIS EVENING.

...THE ITCZ...

THE CONVENTIONAL CONFLUENCE OF WINDS ASSOCIATED WITH THE ITCZ IS
BEING DISRUPTED BY THE LARGE SCALE SFC CYCLONIC FLOW GENERATED
BY THE TROPICAL WAVE CURRENTLY WEST OF THE CAPE VERDE ISLANDS
AND A WEAK SURFACE TROUGH LOCATED OVER THE TROPICAL CENTRAL ATLC
FROM 12N42W TO 8N48W. THIS SCENARIO ONLY ALLOWS FOR A SMALL PART
OF THE ITCZ TO DEVELOP...ANALYZED ALONG 9N32W 7N36W 9N41W.
SCATTERED WEAK TO MODERATE CONVECTION IS FROM 8N-12N BETWEEN
39W-48W. THIS AREA OF CONVECTION IS MOSTLY RELATED TO THE
SURFACE TROUGH. MODERATE TO STRONG CONVECTION IS MOVING OFF THE
COAST OF AFRICA FROM 2N TO 11N E OF 21W.

...DISCUSSION...

THE GULF OF MEXICO...
A BROAD MID-UPPER RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
CENTRAL GULF CONTINUES TO DOMINATE MOST OF THE AREA OF
DISCUSSION THIS AFTERNOON...GIVING MOSTLY CLEAR SKIES WITH FEW
AREAS OF SCATTER LOW LEVEL STRATOCUMULUS CLOUDS EMBEDDED IN THE
LIGHT ESE SFC FLOW...EXCEPT THE FAR NW BASIN...WHERE 15 KT TO 20
KT RETURN FLOW IS OBSERVED FROM THE COASTAL WATERS NEAR
MATAMOROS MEXICO TO THE BORDER BETWEEN THE LOUISIANA/TEXAS
COAST. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE
OVER THE FAR SE BASIN INCLUDING THE FLORIDA STRAITS S OF 25N E
OF 85W...ASSOCIATED WITH THE LARGE SCALE CYCLONIC FLOW FROM
TROPICAL STORM RICHARD AND AN AREA OF DEEP CONFLUENCE OF WINDS
OVER THE WESTERN ATLC. OTHERWISE...STRONG SUBSIDENCE AND DRY AIR
ALOFT WILL CONTINUE OVER THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
TROPICAL STORM RICHARD IS OVER THE NW CARIBBEAN NEAR THE EASTERN
COAST OF HONDURAS PRODUCING SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION W OF 76W. SEE SPECIAL FEATURES ABOVE FOR MORE
DETAILS. ELSEWHERE OUTSIDE THIS AREA OF CONVECTION...SOUTHEAST
CONFLUENT FLOW ALOFT IS OVER THE CENTRAL BASIN BETWEEN 67W AND
76W DRAWING SOME DEEP MOISTURE FROM NW SOUTH AMERICA...ENHANCING
AN AREA OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
BETWEEN 68W AND 73W. STRONG SUBSIDENCE IS ENTERING THE EASTERN
CARIBBEAN E OF 67W. HOWEVER...SCATTERED WEAK CONVECTION IS
MOVING OVER THE LESSER ANTILLES. SHORT RANGE COMPUTER MODELS
CONTINUE THIS TREND FOR AT LEAST THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A BROAD MID-UPPER LEVEL TROUGH IS OVER THE NW ATLC BASIN AND
SUPPORTS A SET OF TWO FRONTAL SYSTEMS THAT ENTER OUR AREA OF
DISCUSSION AS A SURFACE TROUGH NEAR 32N54W TO 25N67W. AN AREA OF
BROAD UPPER LEVEL ANTI-CYCLONIC CIRCULATION IS CENTERED NE OF
THE LESSER ANTILLES NEAR 21N61W. THIS FEATURE COMBINED WITH THE
UPPER TROUGH IN THE WESTERN ATLC IS DRAWING DEEP MOISTURE FROM
THE WESTERN CARIBBEAN ACROSS THE WESTERN ATLC...INTO THE NORTH
CENTRAL ATLC...GENERATING AN AREA OF DEEP LAYER CONFLUENCE ZONE
MARKED BY THE FRONTAL SYSTEM MENTIONED ABOVE. SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ARE WITHIN 80 NM ON EITHER SIDE OF
THE SFC TROUGH AXIS. A COLD FRONT STARS TO DEVELOP WEST OF THE
SURFACE TROUGH AND IS ANALYZED ALONG 32N60W TO 30N73W. WEAK
ISOLATED SHOWERS ARE WITHIN 20 NM EAST OF THE FRONT. AN UPPER
LEVEL LOW IS OVER THE CENTRAL/EAST ATLC SPINNING NEAR 18N42W.
THIS UPPER FEATURE IS PRODUCING AN AREA OF ISOLATED CONVECTION
FROM 18N-27N BETWEEN 32W-41W. THE REST OF THE AREA OF DISCUSSION
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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