000 AXNT20 KNHC 182253 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT NOV 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2215 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 57W S OF 16N MOVING W NEAR 10 KT. WEAK LOW AMPLITUDE INVERTED-V SIGNATURE IS OBSERVED ON THE VISIBLE SATELLITE IMAGERY WITH NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IS ALONG 76W/77W S OF 20N MOVING W NEAR 15 KT. WAVE IS MOVING INTO AN AREA OF SHOWERS/CONVECTION ASSOCIATED WITH A STALLED FRONTAL BOUNDARY IN THE W CARIBBEAN THUS MASKING ANY SATELLITE SIGNATURE. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 7N21W 6N31W 5N53W ACROSS SOUTH AMERICA AND PANAMA INTO THE E PACIFIC REGION. SCATTERED STRONG CONVECTION IS FROM 3N-7N BETWEEN 27W-38W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE INLAND AND WITHIN 75 NM ALONG THE COAST OF AFRICA E OF 12W ACROSS THE PRIME MERIDIAN. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-7N BETWEEN 8W-17W AND FROM 10N TO THE EQUATOR BETWEEN 34W-52W. ...DISCUSSION... GULF OF MEXICO... BROAD DEEP LAYERED TROUGH COVERS THE E HALF OF THE US AND THE GULF OF MEXICO INTO THE W ATLC WITH THE ASSOCIATED FRONTAL BOUNDARY IN THE W ATLC AND CARIBBEAN. A SECOND SURGE OF COLD AIR IS APPROACHING THE GULF CURRENTLY OVER THE SE US. DRY UPPER AIR AND STRONG SUBSIDENCE COVERS THE GULF EXCEPT THE BAY OF CAMPECHE WHERE UPPER LEVEL MOISTURE IS BEING DRAWN ACROSS MEXICO FROM A TROPICAL SYSTEM IN THE E PACIFIC REGION OFF THE COAST OF SW MEXICO. AT THE SURFACE...A RIDGE EXTENDS FROM THE CENTRAL PLAIN STATES OVER THE GULF LEAVING THE GULF SHOWER FEW THIS EVENING. CARIBBEAN SEA... AN UPPER RIDGE DOMINATES MUCH OF THE CARIBBEAN ANCHORED BY AN UPPER HIGH OFF THE COAST OF PANAMA NEAR 11N79W WITH THE RIDGE AXIS EXTENDING NORTHWARD TO OVER W CUBA. AN UPPER TROUGH IN THE CENTRAL ATLC COVERS THE E CARIBBEAN N OF 13N E OF 64W. A STATIONARY FRONT ENTERS THE CARIBBEAN FROM THE W ATLC ACROSS CENTRAL CUBA NEAR 22N79W EXTENDING S TO THE COAST OF NICARAGUA NEAR 14N83W. SCATTERED SHOWERS/THUNDERSTORMS COVER THE AREA FROM 10N-22N BETWEEN 76W-87W. ISOLATED SHOWERS ARE OVER THE NE CARIBBEAN N OF 15N TO OVER PUERTO RICO AND HISPANIOLA BETWEEN 65W-76W WITH THE SE CARIBBEAN RELATIVELY SHOWER FREE. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH THAT COVERS THE E HALF OF THE US AND GULF OF MEXICO COVERS THE W ATLC N OF 22N W OF 70W WITH THE ASSOCIATED STATIONARY FRONT ENTERS THE REGION NEAR 32N69W EXTENDING ACROSS THE CENTRAL BAHAMAS NEAR 25N76W INTO THE CARIBBEAN OVER CENTRAL CUBA. NARROW UPPER RIDGE IS TO THE E EXTENDING FROM HISPANIOLA NEAR 20N71W TO BEYOND 32N64W ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 250/275 NM E OF THE FRONTAL BOUNDARY. UPPER TROUGH IN THE CENTRAL ATLC EXTENDS FROM AN UPPER LOW NEAR 31N56W SSE TO A STRONGER UPPER LOW NEAR 25N52W INTO THE TROPICS NEAR 15N53W. THIS UPPER TROUGH ALSO EXTENDS OVER THE E CARIBBEAN. AT THE SURFACE...A 1010 MB LOW IS JUST N OF THE REGION NEAR 33N61W WITH A SURFACE TROUGH EXTEND SE TO 28N57W AND A SECOND SURFACE TROUGH...PREVIOUSLY AN EXTENSION OF THE TROPICAL WAVE...EXTENDS FROM 26N52W TO 18N55W. A SECOND NARROW UPPER RIDGE EXTENDS FROM THE TROPICS NEAR 19N42W NNW TO BEYOND 32N49W. ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 200/225 NM OF LINE FROM 20N46W TO BEYOND 32N49W. AN UPPER TROUGH COVERS THE E ATLC N OF 21N E OF 38W WITH AN UPPER LOW CENTERED NEAR 31N22W. AT THE SURFACE HOWEVER...A RIDGE COVERS THE SAME AREA WITH ONLY ISOLATED SHOWERS SURROUNDING THE UPPER LOW N OF 25N FROM 18W-28W. $$ WALLACE