000 AXNT20 KNHC 051746 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON OCT 05 2009 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 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 45W S OF 17N MOVING NW 15 KT. LOW AMPLITUDE WAVE MOSTLY EMBEDDED WITHIN THE ITCZ AND EMBEDDED WITHIN A DEEP LAYER MOISTURE MAXIMUM PEAK AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD MID LEVEL CYCLONIC TURNING CAN BE OBSERVED IN THE VISIBLE SATELLITE IMAGERY. ASSOCIATED CONVECTION IS BEING ENHANCED BY A BROAD E/W UPPER RIDGE THAT IS ANCHORED TO THE E OF THE WAVE AXIS. LARGE CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN 45W-49W. TROPICAL WAVE IS ALONG 58W S OF 14N MOVING W NEAR 15 KT. WAVE IS NOT AS WELL DEFINED AS 24 HOURS AGO BUT REMAINS LOW AMPLITUDE WAVE. WAVE ALSO COINCIDES WITH A LOW AMPLITUDE DEEP LAYER MOISTURE MAXIMUM AS INDICATED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-11N BETWEEN 56W-59W. TROPICAL WAVE IS ALONG 82W S OF 17N MOVING W 10-15 KT. WAVE IS BEGINNING TO LOSE DEFINITION AS IT APPROACHES CENTRAL AMERICA. WAVE REMAINS IS NOW EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE MAXIMUM AS INDICATED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 12N-15N W OF 80W TO INLAND OVER NICARAGUA AND WITHIN 75 NM ALONG THE COAST OF THE REMAINDER OF THE NICARAGUA AND ALL OF COSTA RICA BEING ENHANCED BY AN UPPER LEVEL FEATURE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 6N30W 13N46W 10N62W. NUMEROUS STRONG CONVECTION IS INLAND AND ALONG THE IMMEDIATE COAST OF GUINEA W AFRICA. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE WITHIN 90 NM EITHER SIDE OF THE ITCZ FROM 28W-37W. SCATTERED MODERATE CONVECTION IS N OF THE ITCZ FROM 13N-15N BETWEEN 49W-55W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE ANCHORED ALONG THE COAST OF CENTRAL MEXICO NEAR TUXPAN EXTENDING ACROSS THE GULF TO THE STRAITS OF FLORIDA. AN UPPER TROUGH IS OVER THE NE US EXTENDING S TO THE N PORTION OF THE GULF COAST STATES AND DRAPING A COLD FRONT INTO THE REGION FROM A 1011 MB LOW N OF NEW ORLEANS LOUISIANA ALONG THE COAST FROM CAMERON LOUISIANA TO GALVESTON TEXAS THEN CONTINUING INLAND OVER CENTRAL TEXAS. THE UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO ENHANCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 27N W OF 89W AND ISOLATED SHOWERS ACROSS THE REMAINDER OF THE N GULF S OF THE FRONT N OF 28N BETWEEN 89W-95W. THE REMAINDER OF THE GULF IS ENJOYING RATHER TRANQUIL WEATHER THIS AFTERNOON WITH RELATIVELY CLEAR SKIES. CARIBBEAN SEA... BROAD UPPER RIDGE THAT COVERS THE GULF EXTENDS OVER THE NW CARIBBEAN FROM THE WINDWARD PASSAGE TO NE HONDURAS WITH A SECOND UPPER RIDGE COVERING THE E CARIBBEAN ANCHORED OVER NE VENZUELA. THIS SCENARIO IS CREATING A SHARP INVERTED TROUGH FROM W PANAMA/COSTA RICA TO HISPANIOLA BETWEEN HAITI AND THE DOMINICAN REPUBLIC. THE UPPER RIDGE OVER W CARIBBEAN IS USHERING IN DRY STABLE AIR W OF UPPER TROUGH GIVING THAT AREA MOSTLY CLEAR SKIES. THE INVERTED UPPER TROUGH IS ENHANCING THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 82W AND GENERATING ISOLATED SHOWERS WITHIN 150 NM OF LINE FROM HISPANIOLA TO CENTRAL PANAMA. A WEAKENING SURFACE TROUGH IS OVER E PUERTO RICO ALONG 65W FROM 16N-20N. FRESH TO STRONG EASTERLY TRADE WINDS COVER MOST OF THE CARIBBEAN AND ARE USHERING IN ISOLATED LOW LEVEL FAST MOVING SHOWERS ACROSS THE THE AREA E OF 76W. ATLANTIC OCEAN... THE BROAD UPPER RIDGE THAT COVERS THE GULF OF MEXICO NARROWS AS IT EXTENDS OVER THE W ATLC THROUGH THE STRAITS OF FLORIDA ALONG 27N73W TO BEYOND 32N65W ENHANCING ISOLATED SHOWERS N OF 30N W OF 60W. THE NARROW UPPER TROUGH ENTERING THE AREA JUST TO THE E ALONG 32N58W TO THE TURKS AND CAICOS NEAR 21N72W SUPPORTING A COLD FRONT THAT REMAINS N OF THE REGION AND A WEAK SURFACE TROUGH THAT EXTENDS FROM NEAR BERMUDA TO 27N70W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM SE OF THE TROUGH N OF 27N. AN UPPER LOW IS IN THE CENTRAL ATLC NEAR 29N50W COVERING THE AREA N OF 23N BETWEEN 43W-56W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 26N-29N BETWEEN 41W-47W. THE E/W UPPER RIDGE THAT HAS DOMINATED MUCH OF THE TROPICS IS NOW ANCHORED NEAR 15N35W ENHANCING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALONG 45W. WEAK SURFACE RIDGE CUTS A SWATH ACROSS THE REGION BETWEEN 20N-30N WITH A 1020 MB HIGH NEAR 23N37W AND A 1018 MB HIGH IN THE W ATLC NEAR 28N72W. $$ WALLACE