000 AXPZ20 KNHC 192225 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC TUE DEC 19 2006 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 4N78W 6N100W 7N100W 5N107W 8N112W 5N128W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS WEST OF 128W...AND ALSO WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN 119W-122W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN 78W-80W. ...DISCUSSION... N OF 20N... A VERY PRONOUNCED FAST-MOVING SHORTWAVE TROUGH COVERS THE AREA EAST OF 118W WITH ITS AXIS EXTENDING FROM A LARGE MID TO UPPER LEVEL CYCLONIC CIRCULATION OVER NEVADA SOUTH-SOUTHWESTWARD THROUGH 28N111W TO 22N112W.127.5W. DIFFLUENT FLOW PATTERN EXISTS TO THE SOUTHEAST OF THE TROUGH TO OVER WESTERN MEXICO. UPPER LEVEL DEBRIS MOISTURE IN THE FORM OF MOSTLY BROKEN MID AND HIGH LEVEL CLOUDINESS FROM THE DEEP TROPICS CONTINUES TO BE CHANNELED NORTHEASTWARD TOWARDS MEXICO AHEAD OF THE TROUGH. MOST RECENT SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE AND DRY AIR OVER THE AREA EAST OF 133W TO BAJA CALIFORNIA AND MEXICO. WEAK MID/UPPER LEVEL RIDGING WEST OF THE TROUGH IS ALONG 125W AND STRETCHES NORTH OF THE REGION TO A CREST NOW APPROACHING CALIFORNIA. THIS RIDGE IS FORECAST TO MOVE QUICKLY EAST OF THE AREA OVER THE NEXT 24-30 HOURS AS IT FLATTENS OUT IN ADVANCE OF ANOTHER STRONG AND FAST MOVING SHORTWAVE TROUGH WHICH HAS ALREADY ENTERED THE NORTHWEST PORTION OF THE REGION FROM ABOUT 32N1133W SOUTHWESTWARD TO 25N140W AND CONTINUES WELL SOUTHWEST OF THE REGION TO SOUTH OF THE HAWAIIAN ISLAND CHAIN NEAR 17N158W. THIS TROUGH IS FORECAST TO REACH CENTRAL AND SOUTHERN CALIFORNIA WED INTO THU. TO THE EAST OF THIS RIDGING...MID/UPPER LEVEL TROUGHING EXTENDS SOUTHWESTWARD TO WELL SOUTH OF 20N. S OF 20N... THE TROPICS CONTINUES TO BE DOMINATED BY MID TO UPPER LEVEL RIDGING ALONG 9N WEST OF 100W WITH A SMALL UPPER LEVEL ANTICYCLONIC CIRCULATION EVIDENT NEAR 9N117W. CONVECTION ALONG THE ITCZ IS ENHANCE UNDER THIS RIDGE MAINLY WEST OF 123W. BROAD ANTICYCLONIC FLOW COVERS JUST ABOUT THE ENTIRE AREA...EXCEPT FOR THE FAR EASTERN PORTION WHERE THE TROUGH MENTIONED ABOVE DIGS WELL SOUTHWARD INTO THE TROPICS FROM CENTRAL AMERICA TO NEAR 2N98W. A SMALL UPPER LEVEL ANTICYCLONIC CENTER MOVING WESTWARD AT 15-20 KT IS NEAR 2N90W. MOSTLY STRONG SUBSIDENCE AND ASSOCIATED DRY AIR COVERS THE EASTERN PART EAST OF 102W. ONLY SCATTERED TO LOCALLY BROKEN LOW CLOUDS WITH ISOLATED SHOWERS AND THUNDERSTORMS MOVING WESTWARD ABOUT 10-15 KT ARE NOTED SOUTH OF 8N NEAR THE ITCZ EAST OF 100W. LOW LEVELS FOR THE ENTIRE DISCUSSION REGION...HIGH PRESSURE OF 1027 MB IS ANALYZED NEAR 30.5N130W WITH A RIDGE EXTENDING SOUTHEASTWARD THROUGH 26N122W TO 23N114W. HIGH PRESSURE COVERS THE AREA NORTH OF 15N WEST OF 110W. SURFACE COLD FRONT ASSOCIATED WITH THE MID/UPPER LEVEL THAT HAS RECENTLY ENTERED THE NORTHWEST PART OF THE AREA EXTENDS FROM 32N140W TO WELL WEST OF THE AREA WHERE IT IS BECOMING DIFFUSED. THIS FRONT WILL INTO THE NORTHWEST CORNER OF THE WED AND WILL LIKELY BE PRECEDED BY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS...ALTHOUGH STRONGEST OF THE ACTIVITY AND WINDS ASSOCIATED WITH THIS FRONTAL SYSTEM SHOULD REMAIN NORTH OF THE REGION. SCATTERED TO BROKEN COLD AIR STRATOCUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE NOTED NORTH OF 20N AND WEST OF 119W. CLOUDS EAST OF 133W ARE MOVING SOUTH-SOUTHWEST AND THOSE WEST OF 133W ARE MOVING GENERALLY WESTWARD EXCEPT NORTHWEST NORTH OF 27N WEST OF 137W IN RESPONSE TO SOUTH-EASTERLY FLOW AHEAD OF THE APPROACHING COLD FRONT. GAP WINDS...N-NE WINDS TO 20 KT PRESENTLY IN GULF OF TEHUANTEPEC EXPECTED TO LAST FOR ABOUT 24 HOURS. NE WINDS TO 20 KT SEAS TO 8 FT IN THE GULF OF PAPAGAYO EXPECTED TO CONTINUE FOR 48 HOURS AS JUST ENOUGH OF A TIGHT PRESSURE GRADIENT OVER CENTRAL AMERICA AND THE WESTERN CARIBBEAN HOLDS. NW WINDS TO 20 KT ACROSS THE SEA OF CORTEZ ARE EXPECTED TO INCREASE TO 20-25 KT IN 48 HOURS SOUTH OF 26N. $$ AGUIRRE