000 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