000 AXPZ20 KNHC 061624 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI APR 6 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 8N78W 7N90W 7N100W 6N110W 5N120W 4N130W 6N140W. SCATTERED MODERATE TO STRONG CONVECTION EXISTS FROM 4N-7.5N BETWEEN 80-84W...WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 99W-102W...AND ALSO BETWEEN 125W-128W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 104.5W-106W...AND WITHIN 30 NM EITHER SIDE OF AXIS BETWEEN 86W-89W. ...DISCUSSION... A PROGRESSIVE PATTERN DOMINATES THE AREA WITH MID/UPPER LEVEL RIDGING EARLIER EXTENDING NORTH TO SOUTH ACROSS BAJA NOW SHIFTED TO OVER CENTRAL MEXICO...AND A CUT-OFF MID/UPPER LOW EARLIER JUST NORTH OF THE NORTHEAST CORNER NOW PULLING NEWD ACROSS SOUTHERN CALIFORNIA IN ADVANCE OF A RATHER VIGOROUS MID/UPPER LEVEL TROUGH JUST CROSSING INTO THE NORTHWEST CORNER OF THE DISCUSSION AREA. A MID/UPPER LEVEL TROUGH TRAILS SOUTH FROM THE LOW THROUGH NORTHERN BAJA THEN SOUTHWEST TO 16N117W TO 22N122W. CONFLUENT FLOW TO THE WEST OF THE TROUGH IS RESULTING DRY STABLE AIR BEHIND THE TROUGH TO A LINE FROM 32N130W TO 15N136W TO 23N140W AS EVIDENT IN THE MODERATE TO SUBSIDENCE DISPLAYED ON WATER VAPOR IMAGERY. A SUBTROPICAL JET STREAM BRANCH ENTERS THE WESTERN PART OF THE DISCUSSION AREA THROUGH 16N140W...AND EXTENDS NORTHEAST ROUNDING THE SOUTHERN PERIMETER OF THE TROUGH ALONG 19N130W 22.5N120.5W TO ACROSS CENTRAL BAJA CALIFORNIA AND TO NORTHERN MEXICO. AMPLE DEEP TROPICAL MOISTURE SEEN IN THE FORM OF BROKEN CIRRUS CLOUDS WITHIN 450 NM SOUTHEAST OF THE JET STREAM ARE SUGGESTING TRANSVERSE BANDING BETWEEN 114W-123W. RIPPLES OF ENERGY ALONG THE JET STREAM ARE PROPAGATING QUICKLY TO THE NORTHEAST MAINLY EAST OF 132W WHERE SATELLITE DERIVED UPPER AIR DATA INDICATED MAXIMUM JET CORE WINDS IN THE RANGE OF 70-95 KT. THE NEXT COLD FRONT TO MOVE INTO THE REGION WILL BE ASSOCIATED WITH THE AFOREMENTIONED TROUGH MENTIONED ABOVE...AND IS EXPECTED IN THE NORTHWEST CORNER LATE THIS AFTERNOON AND THIS EVENING...ALTHOUGH IT STILL APPEARS THAT IT WILL BE WEAKENING AT THAT TIME. SOUTHWEST WINDS OVER THE NW PART WILL INCREASE TO 20 KT TODAY WITH LARGE NW SWELL SPREADING INTO THE AREA. WINDS THEN DIMINISH IN ABOUT 24 HRS...HOWEVER THE SWELLS REMAIN. OVERCAST MOSTLY MID AND UPPER LEVEL CLOUDS ASSOCIATED WITH THE MID/UPPER TROUGH ARE ALREADY IMPACTING THE AREA NORTH OF 25N WEST OF 128W. BROKEN LOW CLOUDS WITH WIDELY SCATTERED SHOWERS ARE JUST NORTHWEST OF THE AREA ALONG AND NEAR THE FRONT...AND ARE EXPECTED TO MOVE INTO THE NORTHWEST PART THIS AFTERNOON WITH THE FRONT. THE MID/UPPER LEVEL FLOW JUST WEST OF THE AREA BECOMES SHARPLY NORTHWEST TO NORTH DUE TO LARGE MID/UPPER ANTICYCLONIC HIGH WEST SITUATED WELL TO THE WEST OF 140W. A MID/UPPER LEVEL TROUGH AXIS IS SEEN ON WATER VAPOR IMAGERY EXTENDING FROM ROUGHLY 11N106W SOUTHWEST TO BEYOND THE EQUATOR AT 110W. THIS TROUGH IS ENHANCING ITCZ CONVECTION EAST OF TROUGH FROM 4N-7N EAST TO 98W. MID/UPPER LEVEL RIDGING EXTENDS ALONG 6N TO THE EAST OF THE TROUGH SUPPORTING CONVECTION ELSEWHERE ALONG THE ITCZ EAST OF 98W. THE TROUGH IS FORECAST TO MOVE EAST THROUGH SAT THEN DISSIPATE LATE SAT INTO SUN. BROAD MID/UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA SOUTH OF 10N WEST OF THE TROUGH. CONVECTION IS ALSO ACTIVE ALONG THE ITCZ FROM 4N-6N BETWEEN 125W-128W. GAP WINDS...NO UPDATED QUIKSCAT DATA WAS AVAILABLE THIS MORNING FOR THE DISCUSSION AREA...HOWEVER THE MINIMAL GALE ACROSS THE GULF OF TEHUANTEPEC SHOULD LAST ANOTHER 6 HOURS...DIMINISHING TO LESS THAN 20 KT IN ABOUT 36 HOURS. PAPAGAYO WINDS MAY BRIEFLY INCREASE TO 20 KT SAT MORNING AND AGAIN SUN MORNING DUE TO THE WIND REGIME ACROSS COSTA RICA ENHANCED BY SLIGHT TIGHTENING OF THE GRADIENT AND INTERACTING UPON THE LOCAL GEOGRAPHY FOUND THERE. $$ AGUIRRE