000 AXNT20 KNHC 261756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE SEP 26 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURE... A 1010 MB SURFACE LOW PRESSURE CENTER IS NEAR 20.5N48.6W. THIS LOW CENTER HAS BEEN DRIFTING NORTHWEST DURING THE LAST FEW DAYS. CLOUDINESS AND SHOWERS ASSOCIATED WITH IT HAVE NOT BECOME ANY BETTER ORGANIZED THIS MORNING. HOWEVER...THIS SYSTEM STILL HAS SOME POTENTIAL FOR TROPICAL CYCLONE FORMATION DURING THE NEXT DAY OR TWO AS IT CONTINUES TO MOVE TO THE NORTHWEST AROUND 10 MPH. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS NE OF THE LOW PRES CENTER FROM 21N-14N BETWEEN 45W-48W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 34W SOUTH OF 16N MOVING WEST 15 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE MAINLY BEHIND THE WAVE AXIS FROM 9N-12N BETWEEN 25W-35W. A DIFLUENT PATTERN ALOFT IS SUPPORTING THIS CONVECTIVE ACTIVITY. TROPICAL WAVE IS ALONG 52W SOUTH OF 16N DRIFTING WEST. THIS WAVE HAS BEEN MOVING IN TANDEM WITH A 1010 MB SURFACE LOW PRESSURE MENTIONED IN THE SPECIAL FEATURE SECTION. ISOLATED SHOWERS ARE RELATED TO THE WAVE. A TROPICAL WAVE EXTENDS FROM THE SOUTHERN BAHAMAS ACROSS HISPANIOLA TO NEAR LAKE MARACAIBO IN VENEZUELA. THE NORTHERN PORTION OF THE WAVE IS GENERATING SCATTERED SHOWERS OVER THE SOUTHERN BAHAMAS AND IS INTERACTING WITH AN UPPER LOW OVER THIS AREA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N16W 9N30W 8N40W 10N50W 10N60W. OUTSIDE FROM THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-14N EAST OF 21W TO INLAND IN WEST AFRICA PROBABLY ASSOCIATED WITH THE NEXT TROPICAL. A 1013 MB LOW PRES IS NEAR 15N16W. THE GFS MODEL DEVELOPS THIS LOW AND MOVES MAINLY NORTH OVER THE E ATLC. SCATTERED MODERATE CONVECTION IS WITHIN 40-50 NM ON EITHER SIDE OF THE AXIS FROM 38W-44W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 1500 UTC...A FRONTAL SYSTEM EXTENDS FROM CENTRAL FLORIDA TO THE BAY OF CAMPECHE. A 1012 MB SURFACE LOW PRES HAS FORMED ALONG THE FRONTAL BOUNDARY NEAR 31N79W. THE WESTERN PORTION OF THE FRONT...OVER THE BAY OF CAMPECHE HAS BECOME NEARLY STATIONARY. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY...MAINLY S OF 24N AND WEST OF 94W. THE FRONT IS EXPECTED TO EXTEND FROM TAMPA BAY TO THE BAY OF CAMPECHE THIS AFTERNOON AND WILL GRADUALLY WEAKEN ON WED. A BROAD UPPER TROUGH THAT EXTENDS OVER THE EASTERN U.S. IS SUPPORTING THIS FRONT. AN UPPER HIGH IS CENTERED OVER WESTERN MEXICO NEAR 22N106W. A RIDGE EXTENDS FROM THIS UPPER HIGH ACROSS THE ENTIRE GULF INTO FLORIDA AND THE W ATLC. SE OF THE RIDGE LIES AN UPPER TROUGH WHICH IS OVER THE SOUTHERN BAHAMAS AND EASTERN CUBA. DRY AIR COVERS THE NORTHERN GULF WATERS AND THE SE PORTION OF THE GULF...WESTERN CUBA AND THE YUCATAN PENINSULA. IN BETWEEN...THERE IS A BAND OF UPPER LEVEL MOISTURE RELATED TO THE FRONTAL SYSTEM. ABUNDANT UPPER LEVEL MOISTURE ALSO COVERS THE MAJORITY OF MEXICO. HIGH PRES IS BUILDING IN BEHIND THE FRONT. A 1025 MB SURFACE HIGH IS CURRENTLY INLAND OVER NE MEXICO NEAR 28N100W. THE CARIBBEAN SEA... A MID/UPPER TROUGH IS EXTENDING ACROSS THE SOUTHERN BAHAMAS AND EASTERN CUBA INTO THE NW CARIBBEAN. AN UPPER ANTICYCLONE SITUATED NEAR 12N78W DOMINATES THE CENTRAL CARIBBEAN AND CENTRAL AMERICA. THIS FEATURE IS ENHANCING THE DEVELOPMENT OF AN AREA OF CLOUDINESS WITH EMBEDDED MODERATE TO STRONG CONVECTION BETWEEN JAMAICA AND CABO GRACIAS A DIOS IN NICARAGUA. THIS ACTIVITY IS MOVING MAINLY TO THE NORTH AND AROUND THE NORTHERN PERIPHERY OF THE UPPER HIGH. THE UPPER ANTICYCLONE ALSO EXTENDS A RIDGE OVER THE EASTERN CARIBBEAN. THE COMBINATION OF THE ATLC RIDGE AND THE COLOMBIAN LOW IS PRODUCING MODERATE/STRONG TRADES OVER THE S/CENTRAL CARIBBEAN. EARLIER QUIKSCAT PASS SHOWED AROUND 20 KT WINDS IN THE AREA...WITH THE STRONGEST WINDS MAINLY JUST OFF THE COAST OF COLOMBIA. SCATTERED MODERATE SHOWERS IN THE SURFACE ELY TRADE WINDS ARE AFFECTING THE EASTERN CARIBBEAN...PARTICULARLY EAST OF 68W. THE ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE W ATLC. AN UPPER LOW IS JUST EAST OF THE RIDGE NEAR 26N68W. AN UPPER TROUGH EXTENDS FROM THIS LOW ACROSS THE SOUTHERN BAHAMAS AND EASTERN CUBA INTO THE NW CARIBBEAN. ANOTHER UPPER LOW IS OVER THE CENTRAL ATLC NEAR 24N56W. THIS LOW IS GENERATING SOME SWLY SHEAR OVER THE AFOREMENTIONED SURFACE LOW PRES CENTER. BROAD UPPER HIGH LOCATED NW OF THE CAPE VERDE ISLANDS NEAR 18N35W DOMINATES THE REMAINDER OF THE E ATLC. AT THE SURFACE...A 1023 MB SURFACE HIGH IS NEAR 32N45W. THIS SYSTEM EXTENDS A RIDGE OVER THE W ATLC... INCLUDING THE BAHAMAS...CUBA AND SOUTH FLORIDA AS WELL AS ACROSS PART OF THE CENTRAL AND E ATLC. APART FROM THE SHOWER ACTIVITY ASSOCIATED WITH THE SFC LOW PRES...ONLY PATCHES OF LOW/MID CLOUDS ARE SEEN OVER THE ATLANTIC OCEAN EAST OF 40W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE E OF THE BAHAMAS AND W OF 70W DUE TO A FRONTAL BOUNDARY OVER THE NW CORNER OF THE AREA AND AN UPPER LOW OVER THE SOUTHERN BAHAMAS. $$ GR