000 AXNT20 KNHC 090005 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 08 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... SUBTROPICAL STORM GABRIELLE HAS BEEN DESIGNATED AS A TROPICAL STORM AT 08/2100 UTC...BASED ON AMSU DATA AND AIRCRAFT DATA... THAT SUGGEST THAT A WEAK WARM CORE IS PRESENT. GABRIELLE ALSO HAS TAKEN ON MORE OF THE APPEARANCE OF A SHEARED TROPICAL CYCLONE. THE CENTER OF TROPICAL STORM GABRIELLE AT 09/0000 UTC IS NEAR 32.7N 75.2W...ABOUT 130 NM/240 KM SOUTHEAST OF CAPE LOOKOUT NORTH CAROLINA. GABRIELLE IS MOVING NORTHWEST 7 KT. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. PLEASE REFER TO THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/ WTNT22 KNHC AND/OR THE PUBLIC ADVISORY MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. THE OFFICIAL FORECAST TRACK SHOWS GABRIELLE PASSING NEAR OR OVER THE OUTER BANKS OF NORTH CAROLINA DURING THE NEXT 24 TO 36 HOURS. THE NEW FORECAST ALSO CALLS FOR GABRIELLE TO BE ABSORBED BY A LARGER SYSTEM OVER THE NORTH ATLANTIC BY 120 HOURS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 32N TO 34N BETWEEN 75W AND 76W ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 28W/29W SOUTH OF 16N MOVING WEST 15 KT. NUMEROUS STRONG THUNDERSTORMS IN CELLS FROM 10N TO 11N BETWEEN 31.5W AND 32.5W. WARMING CLOUD TOP TEMPERATURES IN CELLS FROM 13N TO 14N BETWEEN 25W AND 26W. ISOLATED MODERATE SHOWERS ELSEWHERE FROM 7N TO 15N BETWEEN 25W AND 34W. THIS SYSTEM HAS THE POTENTIAL FOR SOME DEVELOPMENT DURING THE NEXT FEW DAYS AS IT MOVES WESTWARD AT ABOUT 15 MPH. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 53W SOUTH OF 21N MOVING WEST 15 KT. ISOLATED MODERATE SHOWERS FROM 12N TO 20N BETWEEN 50W AND 58W. A WEAK TROUGH IS ALONG 49W FROM 10N TO 14N. A LOW PRESSURE CENTER WEAKENED FROM 24 HOURS AGO...LEAVING THE TROUGH. MOISTURE FROM THIS WAVE SHOULD AFFECT THE LEEWARD ISLANDS SUNDAY EVENING AND THE UK/US VIRGIN ISLANDS AND PUERTO RICO ON MONDAY. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 86W/87W SOUTH OF 22N MOVING WEST 15 KT. THE AXIS OF THE WAVE CROSSES HONDURAS AND NORTHWESTERN NICARAGUA. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 12N TO 14N BETWEEN 87W AND 88W FROM NORTHWESTERN NICARAGUA INTO SOUTHERN HONDURAS. OTHER CELLS OF NUMEROUS STRONG THUNDERSTORMS ARE IN NORTH CENTRAL COASTAL HONDURAS...WEST CENTRAL HONDURAS...AND ALONG THE HONDURAS/EL SALVADOR BORDER WITHIN A 30 NM RADIUS OF 14N89W. WARMING CLOUD TOP TEMPERATURES AND DISSIPATING PRECIPITATION IN EXTREME EASTERN HONDURAS. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ALSO ARE WITHIN 15 TO 30 NM ON EITHER SIDE OF 19N89W 21N87W IN THE EASTERN YUCATAN PENINSULA OF MEXICO. ...THE ITCZ... 15N17W 11N27W 6N39W 8N51W 9N55W 8N62W. ISOLATED MODERATE SHOWERS WITHIN 250 NM ON EITHER SIDE OF THE AXIS EAST OF 30W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 4N TO 11N BETWEEN 30W AND 43W. NUMEROUS STRONG THUNDERSTORMS ARE IN CELLS SPECIFICALLY FROM 10N TO 11N BETWEEN 42W AND 43.5W. ISOLATED MODERATE SHOWERS FROM 5N TO 8N BETWEEN 45W AND 54W. DISCUSSION... THE GULF OF MEXICO...THE CARIBBEAN SEA NORTH OF 17N WEST OF THE WINDWARD PASSAGE...AND THE ATLANTIC OCEAN WEST OF 60W... A DEEP LAYER TROUGH RUNS FROM A 28N79W MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER TO A 25N88W GULF OF MEXICO MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER. A SURFACE TROUGH FROM 30N74W TO THE BAHAMAS NEAR 26N77W TO THE STRAITS OF FLORIDA NEAR 25N80W...INTO THE GULF OF MEXICO NEAR 26N85W...TO 25N90W. WIDELY SCATTERED TO SCATTERED MODERATE SHOWERS/ISOLATED STRONG THUNDERSTORMS COVER THE CARIBBEAN SEA/THE GULF OF MEXICO/THE ATLANTIC OCEAN FROM 18N TO 28N BETWEEN 70W AND 90W...INCLUDING ACROSS THE BAHAMAS/CUBA/FLORIDA. WARMING CLOUD TOP TEMPERATURES AND DISSIPATING PRECIPITATION FROM 22N TO 23N BETWEEN 89W AND 92W. UPPER LEVEL ANTICYCLONIC FLOW COVERS THE REST OF THE GULF OF MEXICO WEST OF THE 25N88W CYCLONIC CENTER. ISOLATED MODERATE SHOWERS FROM 22N TO 24N BETWEEN 92W AND 97W...AND FROM 25N TO 30N BETWEEN 96W AND 99W...MOVING FROM THE GULF WATERS ONSHORE AND INLAND INTO MOSTLY TEXAS...AND A SMALL BIT OF EXTREME NORTHEASTERN MEXICO. THE CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 16N63W. A TROUGH EXTENDS FROM THIS CYCLONIC CENTER TO 22N62W TO THE NORTH...AND TO 13N63W TO THE SOUTH. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS FROM 17N TO 20N BETWEEN 60W AND 70W HAVE BEEN DURING THE LAST 3 TO 4 HOURS. SOME SHOWERS STILL EXIST ACROSS THIS AREA. THE 86W/87W WESTERN CARIBBEAN SEA TROPICAL WAVE...WITH THE ITCZ...AND BROAD SURFACE LOW PRESSURE HAVE HELPED TO MAINTAIN DEEP LAYER MOISTURE SOUTH OF 13N WEST OF 76W. UPPER LEVEL WESTERLY WINDS ARE CUTTING ACROSS THIS AREA ALSO SHEARING SOME OF THE CONVECTIVE CLOUD CLUSTERS. WARMING CLOUD TOP TEMPERATURES AND WEAKENING PRECIPITATION ARE IN THIS AREA NOW. THE REST OF THE ATLANTIC OCEAN... A DEEP LAYER TROUGH PASSES THROUGH 32N50W TO 26N56W TO 25N64W. THIS FEATURE SUPPORTS A COLD FRONT NORTH OF 31N...AND A STATIONARY FRONT SOUTH OF 31N ALONG 31N40W 27N50W 26N60W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF 28N44W 27N47W 26N50W. ISOLATED MODERATE SHOWERS ARE FROM 23N TO 27N BETWEEN 50W AND 60W...AND FROM 20N TO 32N BETWEEN 60W AND 70W. A SURFACE RIDGE PASSES THROUGH 32N23W TO A 1020 MB HIGH PRESSURE CENTER NEAR 27N30W...TO 25N50W. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N13W TO 29N16W. AN UPPER LEVEL RIDGE IS ALONG 8N19W BEYOND 32N28W. UPPER LEVEL ANTICYCLONIC LARGELY COVERS THE ATLANTIC OCEAN EAST OF 40W. $$ MT