000 AXNT20 KNHC 171018 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU APR 17 2008 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. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 4N4W 3N10W 4N24W 2N35W 4N44W 2N52W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-9N BETWEEN 12W-15W AND 45 NM OF LINE FROM 3N11W TO 2N16W. CLUSTERS SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N TO S OF THE EQUATOR W OF 30W TO INLAND OVER SOUTH AMERICA. ...DISCUSSION... GULF OF MEXICO... UPPER RIDGE ANCHORED OFF THE W COAST OF CENTRAL AMERICA IN THE E PACIFIC REGION COVERS THE W GULF WITH THE AXIS EXTENDING FROM THE BAY OF CAMPECHE TO THE COAST OF TEXAS NEAR CORPUS CHRISTI. BROAD DEEP LAYERED TROUGH COVERS THE REMAINDER OF THE GULF E OF 90W INTO THE W ATLC AND DIPPING S INTO THE NW CARIBBEAN. ALL OF THIS IS PROVIDING STRONG SUBSIDENCE AND DRY AIR TO THE GULF. A SURFACE RIDGE EXTENDS FROM NEW ENGLAND OVER THE SE US INTO THE GULF WITH A 1024 MB HIGH OVER SE GEORGIA. RETURN SOUTHERLY FLOW AROUND THE SURFACE RIDGE IS BANKING COLD AIR STRATOCUMULUS CLOUDS ACROSS THE CENTRAL GULF MOSTLY WITHIN 120 NM OF LINE FROM 23N86W TO 28N92W. SOME ISOLATED SHOWERS ARE MOVING FROM THE W ATLC THROUGH THE FLORIDA STRAITS S OF THE FLORIDA KEYS TO CUBA E OF 84W. OTHERWISE THE GULF REMAINS RELATIVELY CLEAR THIS MORNING. THE NEXT COLD FRONT IS EXPECTED TO ENTER THE NW GULF FRI...BUT WILL NOT BE AS STRONG AS THE PREVIOUS FRONT AND WILL BRING THE CHANCE OF SHOWERS TO THE W GULF EARLY ON FRI. CARIBBEAN SEA... THE DEEP LAYERED TROUGH FROM THE W ATLC EXTENDS OVER THE NW CARIBBEAN TO JUST S OF THE CAYMAN ISLANDS FROM HISPANIOLA TO THE YUCATAN CHANNEL. THE ASSOCIATED STATIONARY FRONT CROSSES HISPANIOLA EXTENDING A SURFACE TROUGH S OF THE SOUTHERN PENINSULA OF HAITI TO 17N79W GENERATING SCATTERED SHOWERS WITHIN 120 N OF THE FRONT/TROUGH. UPPER WESTERLY FLOW DOMINATES THE REMAINDER OF THE CARIBBEAN. MODERATE/STRONG NE TO E TRADE WINDS ARE ACROSS THE CARIBBEAN WITH THE HIGHEST WINDS AGAIN THIS MORNING OVER THE E CARIBBEAN...ALONG THE COAST OF COLOMBIA...AND IN THE WINDWARD PASSAGE. THESE TRADE WINDS COUPLED WITH THE FRONTAL BOUNDARY ARE BANKING LOW CLOUDS WITH ISOLATED SHOWERS WITHIN 120 NM OF LINE FROM E CUBA NEAR 20N76W W OF JAMAICA TO THE TIP OF HONDURAS/NICARAGUA. CONVERGENCE OF THE UPPER LEVEL WINDS AND SURFACE FLOW OVER THE SW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM ALONG THE COAST OF CENTRAL AMERICA S OF 11N W OF 80W. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH COVERS THE W ATLC W OF 60W WITH THE MAIN UPPER LOW N OF THE REGION AND A SECOND UPPER LOW NEAR 31N72W. AT THE SURFACE...A COLD FRONT ENTERS THE REGION E OF BERMUDA NEAR 32N63W S ALONG 23N66W THEN SW ACROSS HISPANIOLA NEAR 18N71W CONTINUING INTO THE CARIBBEAN AS A SURFACE TROUGH. HEAVY SHOWERS WITH CLUSTERS OF ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM E OF THE FRONT N OF 22N WITH SCATTERED SHOWERS S OF 23N WITHIN 150 NM W OF THE FRONT AND 90 NM E OF THE FRONT. A SURFACE TROUGH EXTENDS FROM THE 1001 MB LOW N OF THE REGION SW ALONG 29N69W THEN OVER THE CENTRAL BAHAMA ISLANDS TO NEAR 23N77W. ISOLATED SHOWERS DOT THE REMAINDER OF THE AREA W OF THE FRONT TO 81W AND THE COAST OF FLORIDA. BROAD DEEP LAYERED RIDGE COVERS THE REMAINDER OF THE ATLC WITH THE UPPER RIDGE ANCHORED BY AN UPPER HIGH NEAR 28N32W AND THE SURFACE 1030 MB HIGH ANCHORED NEAR 33N43W. THE TYPICAL E/W UPPER RIDGE ACROSS THE TROPICS HAS BEEN SUPPRESSED TO THE S BY THIS STRONG UPPER RIDGE TO THE N AND GENERATING A SHEAR AXIS EXTENDING FROM W AFRICA NEAR 20N16W ALONG 15N30W TO 21N42W. THUS GIVING THE ATLC E OF 60W FAIR WEATHER THIS MORNING. $$ WALLACE