000 AXPZ20 KNHC 180952 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE APR 18 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 0915 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N78W 7N86W 5N100W 5N110W 6N120W 6N130W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE AXIS BETWEEN 84W-89W AND 97W-101W. SIMILAR CONVECTION IS NORTH OF THE ITCZ WITHIN 30 NM RADIUS OF 8.5N123W. ...DISCUSSION... BROAD AND WEAKENING MID/UPPER LEVEL TROUGH IS OVER THE NORTHEAST PART OF THE AREA NORTH OF 21N EAST OF 120W. THE TROUGH IS FORECAST TO DAMPEN OUT AS IT MOVES EAST-NORTHEAST THROUGH THE NEXT 12-18 HOURS. WESTERLY FLOW WILL COVER ALL OF THE NORTHEAST PART OF THE AREA BY 24 HOURS. DRY AIR AND ASSOCIATED MODERATE TO STRONG SUBSIDENCE IS NOTED NORTH OF 23N AND EAST OF 137W. JET STREAM BRANCH ENTERS THE REGION THROUGH 20N140W AND CONTINUES THROUGH 19N125W 23N116W AND NORTHEASTWARD ACROSS SOUTHERN BAJA CALIFORNIA. SATELLITE UPPER AIR DATA INDICATES MAXIMUM WINDS OF UP TO 110 KT WITHIN THE JET STREAM CORE WEST OF 135W. MID/UPPER LEVEL MOISTURE IS BEING CHANNELED EAST-NORTHEAST TOWARDS SOUTHERN BAJA CALIFORNIA AND NORTHERN MEXICO WITHIN 150 NM EITHER SIDE OF THE JET STREAM WEST OF 128W AND ELSEWHERE WITHIN 75 NM EITHER SIDE OF THE JET STREAM. MOSTLY MODERATE SUBSIDENCE IS PRESENT ELSEWHERE SOUTH OF THE JET STREAM TO 12N BETWEEN 110W-130W. AT THE SURFACE...HIGH PRESSURE OF 1030 MB CENTERED NORTH OF THE REGION NEAR 35N132W EXETNDS A RIDGE INTO THE DISCUSSION AREA THROUGH 32N130W 24N120W TO 18N112W. HIGH PRESSURE COVERS THE AREA NORTH OF 15N WEST OF 110W. THE COLD FRONT PREVIOUSLY ANALYZED OVER THE AREA HAS BECOME DIFFUSED AS HIGH PRESSURE DOMINATES. TIGHT PRESSURE GRADIENT EAST AND SOUTH OF THE HIGH IS RESULTING NW 20-25 KT WINDS ALONG THE BAJA COAST AND 20-25 KT NE TRADES NORTH OF OF THE ITCZ TO ABOUT 21N AND WEST OF 123W. WINDS ALONG THE BAJA COAST ARE EXPECTED TO DECREASE WITHIN THE NEXT 18-24 HOURS...AND THE TRADES SHOULD GRADUALLY DECREASE THROUGH THE NEXT 48 HOURS. MODELS INDICATE THAT THE NEXT COLD FRONT WILL ENTER THE NORTHWEST CORNER OF THE AREA BY EARLY THURSDAY MORNING FOLLOWED BY STRONGER HIGH PRESSURE RIDGING BUILDING EASTWARD ALONG THE NORTHERN PORTION THROUGH THE WEEKEND. WEAK UPPER LEVEL ANTICYCLONIC CIRCULATION IS NEAR 5N115W WITH RIDGE EXTENDING WEST-SOUTHWEST THROUGH 3N122W 2N130W TO 4N140W. WEAK/MID UPPER LEVEL TROUGH EXTENDS FROM 13N122W TO 10N124.5W TO NEAR 6N127W. ELSEWHERE ANTICYCLONIC FLOW IS OCCURRING SOUTH OF 21N WEST OF THE TROUGH. THE TROUGH WILL REACH THE FAR EASTERN PART OF THE AREA THIS WEEKEND. ANTICYCLONIC FLOW IS SEEN SOUTH OF 18N WEST OF ABOUT 125W. MODELS FORECAST A RIDGE DEVELOPING 126W/127W SOUTH BY THU...AND MOVING EAST OF AREA INTO MEXICO BY FRI AFTERNOON. UPPER LEVEL TROUGH ASSOCIATED WITH NEXT COLD FRONT WILL SWING INTO THE EXTREME NORTHWEST CORNER OF THE AREA WEDNESDAY NIGHT...AND QUICKLY MOVE EAST REACHING THE EASTERN PORTION FRIDAY AND PULL AWAY FROM THE AREA DURING THE WEEKEND. VERY STRONG WESTERLY WINDS WILL SPREAD INTO THE AREA BEHIND THIS TROUGH NORTH OF ABOUT 20N TO A SIGNIFICANT JET STREAM BRANCH. DIFLUENT FLOW NUDGED BETWEEN THE MID/UPPER LEVEL TROUGH AND THE ANTICYCLONIC CIRCULATION NEAR 5N115W IS HELPING TO SUSTAIN ISOLATED STRONG CONVECTION NORTH OF THE ITCZ BETWEEN FROM 7N-9N BETWEEN 120W-123W AND WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ALONG AND NEAR THE ITCZ WEST OF 123W. FARTHER EAST...MID/UPPER LEVEL TROUGH EXTENDS FROM AN ELONGATED LOW NOW OVER THE WESTERN GULF OF MEXICO NEAR 23N97W SOUTHWEST TO NEAR ACAPULCO AND TO 12N109W. THIS TROUGH IS FORECAST TO MOVE LITTLE THROUGH THE NEXT 24 HOURS THEN BE ABSORBED BY THE THE NEXT TROUGH...WHICH CURRENTLY EXTENDS FROM 13N122W TO 6N127W AS STATED IN EARLIER IN DISCUSSION. EAST OF THE TROUGH...MID/UPPER FLOW PATTERN CONTINUES TO BE ANTICYCLONIC DUE TO A PERSISTENT LARGE MID AND UPPER LEVEL HIGH LOCATED ON SATELLITE WATER VAPOR IMAGERY OVER THE SOUTHWEST CARIBBEAN SEA WITH RIDGE EXTENDING SOUTHWEST ACROSS COSTA RICA TO THE EASTERN PACIFIC NEAR 8N102W. STRONG SUBSIDENCE AND VERY PRONOUNCED DRY AIR COVER THE EASTERN PACIFIC SOUTH OF 12N EAST OF 110W. ONLY A SMALL AREA OF HIGH LEVEL MOISTURE ADVECTING NORTH-NORTHEAST IS SEEN FROM 5N-12N BETWEEN 95W-100W AND EAST OF 90W TO ACROSS MUCH OF SOUTH AMERICA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FIRING UP ALONG THE ITCZ AXIS EAST OF 90W TO ACROSS SOUTH AMERICA. THIN CIRRUS CLOUDS ARE WITHIN 130 NM EITHER SIDE OF LINE FROM JUST NORTH OF THE ITCZ BETWEEN 88W-90W NORTH TO ACROSS HONDURAS AND NORTHERN NICARAGUA. $$ AGUIRRE