000 AXPZ20 KNHC 141640 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT APR 14 2007 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1600 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N78W 5N90W 6N100W 6N110W 4N118W 4N130W 4N140W. SCATTERED MODERATE WITHIN 60 NM EITHER SIDE OF THE AXIS W OF 138.5W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 5N-9N E OF 87W...AND WITHIN 30 NM EITHER SIDE OF LINE 11N89W 13N89W. ...DISCUSSION... THE UPPER LEVEL PATTERN REMAINS FAIRLY AMPLIFIED AND PROGRESSIVE ACROSS THE DISCUSSION AREA. MID/UPPER LEVEL RIDGING IS OVERS THE SW U.S. WHILE A FAST MOVING UPPER LEVEL TROUGH DIGS SWD INTO THE AREA THROUGH 126W AND EXTENDS SW ALONG 27N128W 25N131W SW TO W OF THE AREA AT 20N140W. STRONG NW UPPER LEVEL N FLOW IS NOTED TO THE N OF THIS TROUGH. THE TROUGH IS SUPPORTING A SURFACE COLD FRONT THAT IS WEAKENING COLD FRONT ALONG 30N W OF 130W. SCATTERED TO BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 45 NM EITHER SIDE OF THE FRONT. BROAD ANTICYCLONIC FLOW IS NOTED ON SATELLITE WATER VAPOR IMAGERY S OF 13N W OF 127W. A MID/UPPER LEVEL RIDGE EXTENDS FROM 6N107W SW TO EQ122W. A MID/UPPER LEVEL CYCLONIC CIRCULATION IS NEAR 2N100W. IT IS FORECAST TO BECOME DIFFUSE IN ABOUT 24 HOURS. A SUBTROPICAL JET STREAM BRANCH EXTENDS FROM 14N111W NE THROUGH 18N108W TO ACROSS MEXICO NEAR CABO CORRIENTES WITH MAXIMUM SATELLITE-DERIVED JET CORE WINDS OF 75-90 KT. BROAD MID/UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA SE OF THE JET STREAM. WEAK UPPER LEVEL DIFFLUENCE SEEN BETWEEN 108W-117W IS IN ADVANCE OF A WEAK MID/UPPER LEVEL TROUGH MOVING E 15-20 KT ALONG 124W/125W FROM 10N-19N. CONVECTION IS SPORADIC E OF THE TROUGH ALONG AND WITHIN 300 NM N OF THE ITCZ BETWEEN 100W AND 110W DUE TO THE DIFFLUENCE AND WEAK SFC TROUGH EMBEDDED IN THE ITCZ. A WEAK UPPER LEVEL CYCLONIC CIRCULATION ALSO MOVING E 15-20 KT IS VISIBLE ON WATER VAPOR IMAGERY NEAR 18N124W. UPPER LEVEL DEBRIS CLOUDINESS IS BEING ADVECTED N/NE FROM THE CONVECTION DESCRIBED ABOVE TOWARDS CENTRAL AND SE MEXICO. MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR IS MOVING WWD FROM THE SW CARIBBEAN TO ACROSS CENTRAL AMERICA KEEPING CONVECTION CONFINED TO ALONG THE W COAST OF CENTRAL AMERICA...AND ALSO THE OFFSHORE WATERS OF EL SALVADOR SE TO THE GULF OF PANAMA. NWP MODELS SUGGEST THAT THE UPPER LEVEL FLOW REGIME IS FORECAST TO CHANGE LITTLE THROUGH EARLY NEXT WEEK ALLOWING FOR UPPER MOISTURE TO CONTINUE ACROSS THE SAME AREAS. AT THE SURFACE...A 1032 MB HIGH CENTER MOVING NE 15 KT IS N OF AREA NEAR 32N141W WITH A RIDGE EXTENDING THROUGH 32N145W 27N126W 22.5N118W TO 18N115W. HIGH PRES COVERS THE AREA N OF 14N W OF 116W. THE HIGH IS FORECAST TO BUILD ESE THROUGH EARLY NEXT WEEK INCREASING THE TRADE WIND FLOW OVER THE WRN PORTION OF THE AREA AS WELL...AND THE NW FLOW OVER THE NE PART NEAR THE COAST OF BAJA CALIFORNIA ON SUN. NWW3 WAVEWATCH GUIDANCE INDICATES THAT SEAS MAY BUILD UP TO 13 FT OVER THE NE PART MON AND MON NIGHT...THEN SUBSIDE A LITTLE TUE BEFORE BUILDING ONCE AGAIN WED AND THROUGH THE END OF WEEK AS NW FLOW INCREASES OVER THE NE PART ONCE AGAIN AS RESULT OF A TIGHTENING PRES GRADIENT. GAP WINDS...GALE WARNING IS IN EFFECT FOR THE GULF OF TEHUANTEPEC BEGINNING 12Z SUN AND LASTING FOR ABOUT 24-30 HRS PER 10M WIND GUIDANCE FROM THE NAM MODEL AND 30M WIND GUIDANCE FROM THE GFS MODEL DUE TO A STRONG SPRING COLD FRONT NOW OVER THE NW GULF OF MEXICO FORECAST TO QUICKLY SWEEP EWD ACROSS THE GULF OF MEXICO THROUGH SUN EVENING. $$ AGUIRRE