000 AXPZ20 KNHC 091519 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI JAN 09 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 06N77W 05N100W 08N122W 07N140W. NUMEROUS MODERATE SCATTERED STRONG CONVECTION IS WITHIN 60 NM S AND 180 NM N OF THE AXIS BETWEEN 116W AND 126W. ...DISCUSSION... A LARGE SCALE MID-UPPER TROUGH...WITH A SERIES OF EMBEDDED SHORTWAVES...COVERS MUCH OF THE EPAC W OF 120W. A W TO SW JET AT THE BASE OF THE TROUGH IS GENERATING AND SPREADING TROPICAL MOISTURE OVER MAINLAND MEXICO AND BAJA CALIFORNIA. INSTABILITY NEAR THE JET IS PRODUCING SCATTERED MODERATE CONVECTION FROM 13N-15N BETWEEN 126W-131W. STRONGER CONVECTION EXISTS FARTHER E IN AN UPPER DIFFLUENT ZONE AIDED BY LOW-LEVEL DIRECTIONAL AND SPEED CONVERGENCE WITHIN THE ITCZ (OUTLINED ABOVE). A SLIGHT UPPER DIFFLUENT PATTERN OVER THE FAR E PORTION IS AIDING IN THE DEVELOPMENT OF ISOLATED CONVECTION ALONG AND N OF THE ITCZ AXIS...SHEARED BY STRONG UPPER SLYS...S OF THE COASTS OF PANAMA AND COSTA RICA. NW SWELL WITH PERIODS OF 14-16 SECONDS IS SPREADING ACROSS MUCH OF THE EPAC WATERS. THIS SWELL COMPONENT WILL CONTINUE TO BE ENHANCED BY SET OF STORM SYSTEMS TRACKING WELL NW OF THE AREA. GAP WINDS... WITH A 1036 MB HIGH BUILDING E TOWARD THE PACIFIC NW AND RELATIVELY LOW PRES OVER MAINLAND MEXICO...STRONG NLY FLOW IS EXPECTED TO SET UP OVER THE GULF OF CALIFORNIA. NLY WINDS ARE FORECAST TO INCREASE TO 20 KT LATER TODAY AS THE HIGH SHIFTS INLAND AND TO GALE FORCE TONIGHT AS THE HIGH STRENGTHENS OVER THE GREAT BASIN AND A BACK-DOOR COLD FRONT SLIPS THROUGH N MEXICO. GALE/NEAR GALE CONDITIONS ARE LIKELY TO CONTINUE THROUGH THE WEEKEND AS THE HIGH ONLY SLOWLY BREAKS DOWN. THE GULF OF TEHUANTEPEC BECOMES A CONCERN AS THE NEXT COLD FRONT MOVES INTO THE GULF OF MEXICO. MODELS ARE NOT INDICATING THIS FRONT TO BE VERY STRONG...BUT AS CLIMATOLOGY SUGGEST FRONTS TYPICALLY SURGE S OVER THE BAY OF CAMPECHE AND THIS MAY BE ENOUGH TO PRODUCE A NEAR MINIMAL GALE LATE SUN OR MON. A MUCH STRONGER FRONT LOOKS TO BE MOVING INTO THE GULF OF MEXICO BY MID-LATE WEEK NEXT WEEK...WE WILL CONTINUE TO MONITOR. AS STRONG TRADES CONTINUE OVER THE SOUTHERN HALF OF THE CARIBBEAN SEA...TOPOGRAPHIC EFFECTS WILL ENHANCE 20-25 KT NE FLOW THROUGH THE GULF OF PAPAGAYO OVER THE NEXT FEW DAYS. $$ CANGIALOSI