000 AXNT20 KNHC 221028 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT SEP 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 30W S OF 20N MOVING W 15 KT. NARROW LOW LEVEL INVERTED-V CURVATURE WITH ASSOCIATED CONVECTION EMBEDDED WITHIN THE ITCZ. TROPICAL WAVE IS ALONG 41W/42W S OF 16N MOVING W 10-15 KT. MUCH OF THE WAVE ENERGY IS WITHIN THE ITCZ WITH A VERY BROAD FAINT INVERTED-V CURVATURE. WAVE IS BENEATH A BROAD UPPER HIGH ALSO MASKING THE SIGNATURE WITH ANY CONVECTION TO THE W OF THE WAVE AXIS. TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 74W/75W S OF 18N MOVING W 15 KT. THE N PORTION OF THE WAVE LIES BENEATH AN UPPER LOW AND IS ENHANCING ACTIVITY ASSOCIATED WITH THAT UPPER LOW. THIS SHALLOW WAVE IS ONLY SEEN ON THE MIMIC TPW ANIMATION WHICH DEPICTS A NARROW MODEST MOISTURE SURGE MOVING PAST THE ABC ISLANDS WITH NO ASSOCIATED CONVECTION. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N14W 6N22W 10M40W 7N59W. A 1011 MB LOW IS CENTERED NEAR 6N19W...EMBEDDED WITHIN THE ITCZ...MOVING W NEAR 15 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-12N BETWEEN 18W-24W AND FROM 8N-14N BETWEEN 42W-53W. DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS CENTERED ALONG THE ALABAMA COAST AND IS ASSOCIATED WITH THE REMNANTS OF T.D. TEN THAT WENT INLAND LATE ON FRI AND IS CENTERED NEAR MOBILE ALABAMA. SCATTERED SHOWERS/ THUNDERSTORMS CONTINUE OVER THE N GULF COAST N OF 28N TO OVER FLORIDA FROM PENSACOLA TO THE MISSISSIPPI/LOUISIANA BORDER. BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CENTRAL CUBA INTO THE W ATLC GENERATING DIFFLUENCE AND ADVECTING AN ABUNDANCE OF TROPICAL MOISTURE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-26N BETWEEN 83W-86W AND SCATTERED SHOWERS ACROSS THE FLORIDA PENINSULA AND THE IMMEDIATE COASTAL WATERS. AN UPPER TROUGH COVERS THE REMAINDER OF THE GULF ADVECTING DRY CONTINENTAL AIR ACROSS THE W GULF W OF 90W THUS LIMITING ANY ACTIVITY ACROSS THAT AREA. CARIBBEAN SEA... BROAD UPPER RIDGE COVERS THE W CARIBBEAN W OF 75W EXTENDING FROM CENTRAL AMERICA ACROSS CENTRAL CUBA INTO THE W ATLC WITH A SURFACE TROUGH ANALYZED BENEATH THIS UPPER RIDGE FROM NE YUCATAN NEAR 22N87W ALONG 17N87W OVER HONDURAS/NICARAGUA TO NEAR 13N85W. THIS UPPER RIDGE IS GENERATING DIFFLUENCE AND ADVECTING AN ABUNDANCE OF TROPICAL MOISTURE TO PRODUCE SCATTERED MODERATE/ STRONG CONVECTION WITHIN 100 NM OF LINE FROM 12N80W ALONG 16N83W TO 20N85W AND CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE REMAINDER OF THE AREA W OF 78W. A SMALL UPPER LOW IS OVER HISPANIOLA BUT IS ONLY PRODUCING WIDELY ISOLATED SHOWERS OVER THE ISLAND. UPPER RIDGE FROM THE TROPICAL ATLC COVERS THE REMAINDER OF THE CARIBBEAN WITH DRY SOMEWHAT STABLE AIR E OF 68W. ATLANTIC OCEAN... BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN OVER THE FAR W ATLC W OF 72W ACROSS THE FLORIDA STRAITS GENERATING DIFFLUENCE AND ADVECTING AN ABUNDANCE OF TROPICAL MOISTURE TO SCATTERED SHOWERS/THUNDERSTORMS WITHIN 200 NM ALONG THE E COAST OF THE US N OF 27N TO THE CAROLINAS. THE MAIN FEATURE IN THE CENTRAL ATLC IS A LONG DRAWN OUT SURFACE TROUGH WHICH EXTENDS THROUGH 32N41W ALONG 28N44W 24N53W TO 14N58W. SCATTERED SHOWER/ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE SURFACE TROUGH N OF 26N AND WITHIN 150 NM E OF THE SURFACE TROUGH FROM 17N-26N. THIS SURFACE TROUGH LIES ON THE BOUNDARY BETWEEN AN UPPER TROUGH TO THE NW AND A BROAD UPPER RIDGE COVERING THE TROPICAL ATLC CENTERED NEAR 12N40W. A SECOND UPPER TROUGH IS OVER THE FAR E ATLC EXTENDING FROM THE CANARY TO OVER THE CAPE VERDE ISLANDS BUT IS NOT PRODUCING ANY SIGNIFICANT ACTIVITY. A BROAD SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A 1026 MB HIGH E OF THE AZORES. $$ WALLACE