000 AXPZ20 KNHC 021003 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT APR 02 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...ITCZ... AXIS CENTERED ALONG 2N100W 5N115W 6N122W 2N132W 2N140W. TROUGH IS ALONG 6N90W TO 2N99W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 100W-106W...WITHIN 120 NM S OF THE TROUGH AND ALSO WITHIN 60 NM N OF THE ITCZ BETWEEN 122W-124W. ...DISCUSSION... AN UPPER LEVEL CYCLONIC CIRCULATION EMBEDDED IN A DEEP LAYER TROUGH IS NEAR 30N131W MOVING ENE 25 KT. A TROUGH EXTENDS FROM THE CIRCULATION SW TO W OF THE AREA AT 21N140W. A HIGHLY AMPLIFIED RIDGE IS OVER THE EASTERN PORTION OF THE AREA WITH A LARGE CREST COVERING THE NW CONUS. LATEST SATELLITE IMAGERY ALONG WITH THE 0600 UTC PRES ANALYSIS REVEALS THE ASSOCIATED SURFACE FEATURE RELATED TO THE UPPER LEVEL CYCLONIC CIRCULATION EXTENDING FROM 30N127W SW TO 26N139W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 45-60 NM OF THE TROUGH. THE PRES DIFFERENCE BETWEEN THE TROUGH AND STRONG HIGH CENTERED WELL N OF THE AREA IS CREATING A TIGHT ENOUGH PRES GRADIENT TO THE NW OF TROUGH TO ALLOW FOR NE 20 KT TO MATERIALIZE TO THE NW OF A LINE FROM 30N128W TO 23N140W. SEAS THERE ARE 8-12 FT IN A NW SWELL. THESE WINDS WILL BE FURTHER ENHANCED BY ANOTHER EPISODE OF N-NE 20 KT WINDS THAT WILL BEGIN TO IMPACT THE N CENTRAL WATERS DURING TODAY AS THE PRES GRADIENT BETWEEN THE HIGH TO THE N AND BROAD LOW PRES OVER THE WESTERN U.S. LEADS TO A VERY TIGHT PRES GRADIENT ALONG AND W OF THE WESTERN U.S. ALONG WITH THESE WINDS...YET ANOTHER BATCH OF LONG PERIOD N SWELLS WILL BEGIN TO INVADE THE FAR NORTHERN WATERS WITH SEAS UP TO 12 FT...AND BUILD UP TO POSSIBLY 13 OR 14 FT ALONG 30N SUN. THE UPPER FLOW PATTERN DUE TO A DIFFLUENCE ALOFT E OF THE UPPER LEVEL CYCLONIC CIRCULATION IS CONTINUING TO ADVECT BROKEN HIGH CIRRUS CLOUDS NORTHWARD AND NORTHEASTWARD AWAY FROM THE CIRCULATION AND MAINLY TOWARDS NORTHERN BAJA CALIFORNIA AND THE U.S. WEST COAST. THIS SAME MOISTURE IS ERODING IN DRY STABLE AIR AS IT ENCOUNTERS MODERATE SUBSIDENCE E OF 114W FROM 23N-27N. THE THE UPPER LEVEL CYCLONIC CIRCULATION WILL ACCELERATE TO THE NE AS THE TROUGH IT IS EMBEDDED WITHIN SHIFTS EASTWARD TO INLAND THE WESTERN U.S. TONIGHT...AND THE VERY LARGE BEHIND ALSO SHIFTS EASTWARD. AS THIS HAPPENS THE TROUGH EXTENDING ALONG THE UPPER LEVEL CYCLONIC CIRCULATION WILL THEN DEVELOP ANOTHER UPPER LEVEL CYCLONIC CIRCULATION WHICH BECOMES CUT-OFF SIMILAR TO THE INITIAL ONE OVER THE NW PORTION NEAR 22.5N131W ON SUN. THIS CIRCULATION WILL THEN BECOME LARGER AND DEEPEN THROUGH MON AS IT ALSO BEGINS TO LIFT NORTHEASTWARD TOWARDS FAR NORTHERN BAJA CALIFORNIA AND SOUTHERN CALIFORNIA EARLY NEXT WEEK. A MID/UPPER LEVEL TROUGH OVER THE THE EASTERN PORTION OF THE AREA EXTENDS FROM 16N117W NORTHEASTWARD TO ACROSS NORTHERN MEXICO. TO ITS SE...A WEAK UPPER TROUGH EXTENDS FROM A SMALL MID/UPPER LEVEL CYCLONIC CIRCULATION NOW INLAND OVER CENTRAL MEXICO SW TO 16N106W AND S TO 11N106W TO 5N106W. ONLY SLIGHT ENHANCEMENT TO ITCZ CONVECTION BY THE TROUGH IS NOTED. TO ITS SE...THE MID/UPPER FLOW IS SLY AROUND THE WESTERN PERIPHERY OF A MID/UPPER RIDGE THAT STRETCHES FROM AN UPPER LEVEL ANTICYCLONE NEAR 12N66W NW TO THE YUCATAN PENINSULA. THIS FLOW...CONSISTING OF S TO SW WINDS...CONTINUES TO PUMP UPPER LEVEL MOISTURE IN THE FORM OF BLOW OFF BROKEN TO SCATTERED CIRRUS CLOUDS FROM ITCZ ITCZ CONVECTION N AND NE TO ACROSS MUCH OF CENTRAL AMERICA... AND INTO THE FAR WESTERN CARIBBEAN SEA. OVERALL CONVECTIVE ACTIVITY REMAINS MINIMAL ACROSS THE REGION... WITH MOST OF THE LOW LEVEL CONVERGENCE BEING CROSS-EQUATORIAL ROUGHLY BETWEEN 118W-128W. A WEAK SURFACE TROUGH MOVING W AT 10-15 KT IS EMBEDDED ALONG THE ITCZ...AND WAS ENHANCING ITCZ CONVECTION JUST DURING THE PAST SEVERAL HOURS. THE TROUGH WILL CONTINUE ON WESTWARD OVER THE NEXT 48 HOURS. THE WAVEWATCH WAVE MODEL GUIDANCE SUGGESTS THAT ELSEWHERE W OF A LINE FROM 30N118W TO 18N126W TO 10N133W A SURGE OF LONG PERIOD 15-18 SEC NW SWELLS WITH MAX SEAS OF 8-11 FT WILL SLOWLY SUBSIDE OVER THE NEXT 48 HOURS. $$ AGUIRRE