000 AXPZ20 KNHC 190435 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0415 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N77W 5N86W 6N100W 9N110W 8N122W 6N130W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 118W-127W...FROM 5N-9N BETWEEN 130W-138W...AND ALSO OCCURRING WITHIN 30 NM EITHER SIDE OF THE AXIS BETWEEN 106W-110W. ...DISCUSSION... W OF 110W... A FAST MOVING VERY PRONOUNCED SHORTWAVE TROUGH COVERS THE AREA NORTH OF 15N BETWEEN 113W-128W WITH ITS AXIS EXTENDING FROM A LARGE MID TO UPPER LEVEL CYCLONIC CIRCULATION OVER THE SOUTHEAST PORTION OF SOUTHERN CALIFORNIA SOUTHWESTWARD THROUGH 25N121W TO 15N127.5W. DIFFLUENT FLOW PATTERN SOUTHEAST OF THE TROUGH IS RESULTING IN AN AREA OF ENHANCED DEEP THUNDERSTORM ACTIVITY ...MORE THAN TYPICALLY SEEN FOR THIS TIME OF YEAR...NORTH OF THE ITCZ FROM 10.5N-13N BETWEEN 111W-112W. THIS CONVECTION IS ALSO ASSOCIATED WITH A SURFACE TROUGH LOCATED ALONG 110W/111W AND MOVING WESTWARD 10-15 KT. SOME OF THIS ACTIVITY...ESPECIALLY THE LOW TOP CONVECTION...WILL TRANSLATE WESTWARD OVER THE NEXT 3-4 DAYS. UPPER LEVEL DEBRIS MOISTURE FROM THE DEEP TROPICS IS BEING 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 NORTH OF 19N EAST OF 133W TO BAJA CALIFORNIA. WEAK MID/UPPER LEVEL RIDGING EXTENDS WEST OF THE TROUGH FROM 22N135W NORTHEASTWARD THROUGH 26N132W TO A CREST WELL NORTH OF THE AREA NEAR 33N128W. THIS RIDGE IS FORECAST TO MOVE QUICKLY EASTWARD OVER THE NEXT 24-30 HOURS AND FLATTEN OUT IN ADVANCE OF ANOTHER STRONG AND FAST MOVING SHORTWAVE TROUGH CURRENTLY WEST OF THE AREA EXTENDING FROM ABOUT 32N142W SOUTHWESTWARD TO SOUTHEAST ISLANDS OF THE HAWAIIAN ISLAND CHAIN. THIS TROUGH IS FORECAST TO REACH CENTRAL AND SOUTHERN CALIFORNIA WED INTO THU. THE TROPICS CONTINUES TO BE DOMINATED BY MID TO UPPER LEVEL RIDGING ALONG 8N WEST OF 110W WITH A SMALL UPPER LEVEL ANTICYCLONIC CIRCULATION EVIDENT NEAR 8N125W. CONVECTION ALONG THE ITCZ IS ENHANCE UNDER THIS RIDGE MAINLY BETWEEN 118W-127W AND ALSO WEST OF 130W. E OF 110W... TO THE EAST OF THIS RIDGING...A MID/UPPER LEVEL TROUGH DIGS WELL SOUTHWARD INTO THE TROPICS FROM SOUTHEASTERN MEXICO...WHERE IT IS RATHER SUBTLE...SOUTH ALONG 97W TO THE EQUATOR. THE UPPER LEVEL FLOW IS SOUTHWESTERLY EAST OF THE TROUGH...BECOMING SHARPLY ANTICYCLONIC EAST OF 90W IN RESPONSE TO A NEARLY STATIONARY MID/UPPER LEVEL ANTICYCLONE SEEN ON WATER VAPOR IMAGERY NEAR 7N88W. MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR COVERS THIS AREA EXCEPT FOR THE FAR NORTHWEST SECTOR. ONLY SCATTERED TO LOCALLY BROKEN LOW WITH ISOLATED SHOWERS AND THUNDERSTORMS MOVING WESTWARD ABOUT 10-15 KT ARE NOTED SOUTH OF 8N NEAR THE ITCZ EAST OF 94W. LOW LEVELS FOR THE ENTIRE DISCUSSION REGION...HIGH PRESSURE OF 1029 MB IS ANALYZED NORTH OF THE AREA NEAR 33N131W 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 NEXT MID/UPPER LEVEL TROUGH AS MENTIONED EARLIER IN DISCUSSION IS NEARING THE DISCUSSION AREA FROM 32N143W TO WELL WEST OF THE AREA NEAR 26N156W. THIS FRONT WILL BEGIN TO MOVE INTO THE NORTHWEST CORNER OF THE REGION BY ABOUT LATE WED INTO THU MORNING...AND WILL LIKELY BE PRECEDED BY A BAND OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS...ALTHOUGH STRONGEST OF THE ACTIVITY AND WINDS ASSOCIATED WITH THIS FRONTAL SYSTEM SHOULD REMAIN NORTH OF THE REGION. A 120 NM WIDE BAND...RESIDUAL CLOUDS/SHOWERS FROM AN OLD FRONTAL BOUNDARY EXTENDS FROM 18N125W WESTWARD ALONG 17N131W TO 17N140W. SCATTERED TO BROKEN COLD AIR STRATOCUMULUS CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE NOTED NORTH OF 20N AND WEST OF 119W. CLOUDS EAST OF 131W ARE MOVING SOUTH-SOUTHWEST AND THOSE WEST OF 131W ARE MOVING GENERALLY WESTWARD EXCEPT NORTHWEST NORTH OF 27N AND 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 36 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. SEA OF CORTEZ NW WINDS ARE EXPECTED TO BEGIN IN ABOUT 36 HOURS TO 20 KT THEN INCREASE TO 20-25 KT IN 48 HOURS. $$ AGUIRRE