000 AXNT20 KNHC 231106 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU OCT 23 2008 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 26W/27W S OF 14N MOVING W 5-10 KT. CIMSS WAVETRAK PRODUCT DEPICTS A DISORGANIZED AREA OF LOW LEVEL COUNTERCLOCKWISE CIRCULATION PRESENT NEAR WAVE AXIS. DEEP LAYER DRY AIR IS GENERALLY SUPPRESSING CONVECTION NEAR THE WAVE. HOWEVER...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS OCCURRING WITHIN 150 NM EITHER SIDE OF WAVE AXIS S OF 8N... LIKELY BEING ENHANCED BY LOW LEVEL CONVERGENCE NEAR THE ITCZ. A TROPICAL WAVE IS ALONG 53W/54W S OF 20N MOVING W 5-10 KT. CIMSS WAVETRAK PRODUCT SHOWS THAT WAVE COINCIDES WITH A MAXIMUM IN LOW LEVEL CIRCULATION. WAVE ALSO COINCIDES WITH DEEP LAYER MOISTURE THAT IS BEING DRAWN NORTHWARD BY UPPER LEVEL NORTHERLY FLOW ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE CENTRAL ATLC. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-14N BETWEEN 47W-56W...LIKELY BEING ENHANCED BY LOW LEVEL CONVERGENCE NEAR THE ITCZ. A TROPICAL WAVE IS ALONG 83W S OF 18N MOVING W 10-15 KT. THIS WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE...AS WELL AS A MAXIMUM IN LOW LEVEL COUNTERCLOCKWISE CIRCULATION BASED ON CIMSS WAVETRAK PRODUCT. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 12N-20N BETWEEN 79W-84W. ALSO...ISOLATED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF WAVE AXIS S OF 11N. THIS CONVECTION IS LIKELY BEING ENHANCED BY STRONG UPPER LEVEL DIFFLUENCE TO THE W OF AN UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 17N78W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 8N23W 8N36W 10N50W 9N61W. IN ADDITION TO CONVECTION ASSOCIATED WITH TROPICAL WAVES...ISOLATED MODERATE CONVECTION IS FROM 3N-10N BETWEEN 13W-24W. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF AXIS BETWEEN 29W-47W. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM N OF AXIS BETWEEN 56W-61W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT IS INCREASING OVER THE GULF...AS A VIGOROUS UPPER TROUGH OVER THE S CONUS CONTINUES TO APPROACH THE GULF. AT THE SAME TIME...DEEP MOISTURE IS ROTATING NORTHEASTWARD INTO THE SE GULF AROUND AN UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 17N78W. UPPER LEVEL DIFFLUENCE TO THE N OF THIS UPPER HIGH IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE E GULF S OF 26N E OF 87W...AFFECTING THE FLORIDA PENINSULA AND W CUBA. THIS ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH THAT EXTENDS FROM A 1010 MB SURFACE LOW OVER THE YUCATAN PENINSULA NEAR 19N89W TO 23N88W TO 27N86W. COMPUTER MODEL GUIDANCE INDICATES THAT STRONG UPPER LEVEL DIVERGENCE SE OF A MID/UPPER-LEVEL WIND SPEED MAXIMUM ASSOCIATED WITH THE AFOREMENTIONED VIGOROUS UPPER TROUGH WILL HELP TO CONCENTRATE THE SURFACE TROUGH AND SURFACE LOW OVER THE NE GULF...WITH DEVELOPMENT OF A LOW IN THE NE GULF EXPECTED OVER THE NEXT DAY. ALSO...A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH IS MOVING TO THE SE OVER THE NW GULF. THIS FRONT EXTENDS FROM SW LOUISIANA NEAR 30N93W TO 28N94W TO FAR S TEXAS NEAR 27N97W...WITH ISOLATED SHOWERS AND THUNDERSTORMS WITHIN 120 NM AHEAD OF THE FRONT...AND INCREASED NORTHERLY SURFACE WINDS IN THE WAKE OF THE FRONT. ADDITIONALLY...A SURFACE TROUGH OVER THE W GULF EXTENDS FROM 26N95W TO 23N95W TO 20N93W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. THE 1011 MB SURFACE LOW PREVIOUSLY ANALYZED ALONG THIS SURFACE TROUGH AT 23N94W FOR THE 0000 UTC THURSDAY 23 OCT 2008 MAP IS NO LONGER PRESENT...BECAUSE SATELLITE IMAGERY INDICATES THE CLOSED SURFACE CIRCULATION HAS SINCE GIVEN WAY TO AN OPEN SURFACE TROUGH. ADDITIONALLY...STRONG NORTHERLY WINDS BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC WILL BEGIN TO RESULT IN GALE FORCE WINDS IN THE EASTERN PACIFIC REGION AT 0000 UTC FRIDAY. CARIBBEAN SEA... A SURFACE TROUGH EXTENDS FROM A 1010 MB SURFACE LOW OVER THE YUCATAN PENINSULA NEAR 19N89W INTO THE SE GULF NEAR 23N88W TO 27N86W. BROAD LOW LEVEL CONVERGENCE AROUND THIS TROUGH... COMBINED WITH AMPLE DEEP LAYER MOISTURE AND UPPER LEVEL DIVERGENCE TO THE W OF THE UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 17N78W...IS RESULTING IN ISOLATED MODERATE CONVECTION IN THE NW CARIBBEAN FROM 18N-22N BETWEEN 85W-89W. ALSO...NUMEROUS MODERATE/SCATTERED STRONG CONVECTION FROM 12N-20N BETWEEN 79W-84W IS LIKELY RESULTING FROM THE INTERACTION OF UPPER LEVEL DIFFLUENCE W OF THE UPPER HIGH AND THE TROPICAL WAVE ALONG 83W S OF 18N. TO THE E OF THE AFOREMENTIONED UPPER HIGH...DEEP LAYER DRY AIR AND STABLE ATMOSPHERIC CONDITIONS ARE INHIBITING DEEP CONVECTION OVER THE E CARIBBEAN. ATLANTIC OCEAN... THE FLOW AROUND THE UPPER HIGH IN THE CENTRAL CARIBBEAN NEAR 17N78W IS BRINGING DEEP MOISTURE INTO THE SW ATLC. ADDITIONALLY...A SURFACE COLD FRONT EXTENDS FROM 31N70W TO 30N76W TO E OF NE FLORIDA NEAR 31N81W. THE INTERACTION OF THE FRONT AND INCREASING MOISTURE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 30N W OF 72W...AFFECTING THE FLORIDA PENINSULA AND E CUBA. FARTHER TO THE E...A DEEP LAYER TROUGH IS OVER THE CENTRAL ATLC FROM 17N-30N BETWEEN 47W-61W...AND IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 29N51W TO 27N53W TO 24N53W. DEEP LAYER MOISTURE OVER E PORTIONS OF THE DEEP LAYER TROUGH IS ENHANCING SCATTERED MODERATE CONVECTION FROM 20N-24N BETWEEN 49W-52W. FARTHER TO THE E...AN UPPER RIDGE AXIS EXTENDS FROM 32N38W TO 25N43W TO 14N45W...AND AN UPPER TROUGH IS IN THE E ATLC N OF 11N E OF 37W. GENERALLY DEEP LAYER DRY AIR IS PREVENTING DEEP CONVECTION NEAR THESE FEATURES. ADDITIONALLY...A 1028 MB SURFACE HIGH IS CENTERED NEAR 37N24W...AND A SURFACE RIDGE EXTENDS FROM THIS SURFACE HIGH TO THE SW NEAR 15N38W...WITH SUBSIDENCE AND STABLE CONDITIONS AROUND THESE FEATURES RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE E ATLC. $$ COHEN