000 AXPZ20 KNHC 042204 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON MAY 04 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2130 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N84W 7N90W 7N100W 8N107W 5N120W 7N129W 4N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM N OF THE AXIS BETWEEN 127W-133W AND WITHIN 120 NM S OF THE AXIS BETWEEN 90W-03W. SCATTERED MODERATE CONVECTION EXISTS FROM 4N-8N W OF 136W...AND ALSO S OF THE AXIS WITHIN 30 NM OF 4N98.5W. ...DISCUSSION... A DEEP LAYER AND NEARLY STATIONARY WELL ANCHORED ANTICYCLONE IS NEAR 12N120W WITH A RIDGE EXTENDING NNW TO 17N121W TO 24N125W. A MORE SUBTLE RIDGE EXTENDS FROM THE ANTICYCLONE E TO NEAR 114W. TO THE NW OF THE ANTICYCLONE...AN UPPER LEVEL SMALL CYCLONIC CIRCULATION MOVING W ABOUT 15 KT IS NEAR 17N135W WITH A TROUGH SW TO 15N140W. A JET STREAM BRANCH WITH MAXIMUM WINDS 55 KT ROUNDS THE BASE OF THE TROUGH AND ENTERS THE REGION THROUGH 10N140W...AND SHARPLY TURNS NE TO 15N133W TO 21N127W BEFORE DIVING SE TO 18N116W AND TURNING ENE ROUNDING THE BASE OF A MID/UPPER TROUGH OVER THE FAR ERN PORTION STRETCHING FROM THE NW GULF OF MEXICO SW TO CENTRAL MEXICO AND SW TO A CUT-OFF CYCLONIC CIRCULATION SITUATED NEAR 16N107W. THE TROUGH THEN CONTINUES S FROM THERE TO 10N107W TO 06N107W AND SE TO NEAR THE EQUATOR AT 106W. MODERATE SUBSIDENCE IS PRESENT W OF THE TROUGH TO THE ANTICYCLONE. A DEEP LAYER MOISTURE PLUME CONSISTING OF BROKEN MID AND HIGH CLOUDS ORIGINATES FROM ITCZ-RELATED CENTRAL PACIFIC CONVECTION AND IS BEING CHANNELED NEWD INTO THE AREA VIA THE JET STREAM BETWEEN THE CYCLONIC CIRCULATION NEAR 17N135W AND THE ANTICYCLONE. THE MOSITURE PLUME RIDGES UP AND OVER THE RIDGE CREST TO NEAR 17N124W WHERE THE CLOUDS BECOME SCATTERED AS THE PLUME THINS OUT AND THEN SPILLS SE TO NEAR 13N118W. TO THE NW OF THIS MOSITURE...AND W OF THE CYCLONIC CIRCULATION THE ATMOSPHERE REMAINS PRETTY STABLE AS OBSERVED ON SATELLITE WATER VAPOR IMAGERY WHERE MODERATE TO STRONG SUBSIDENCE IS NOTED. EVEN THE TROPICAL MARINE LAYER CONSISTING OF STRATOCUMULUS CLOUDS HAS SHRUNK...AND IS DEPICTED AS MAINLY BROKEN FROM 15N TO 26N W OF 128W...OR S OF THE SURFACE HIGH CENTERED NEAR 26N133W AND ALSO E OF THE HIGH BETWEEN 118W AND 128W. SCATTERED TO BROKEN DEBRIS CIRRUS CLOUDS EMANATING FROM ITCZ CONVECTION ARE BEING CHANNELED NWD TOWARDS SE MEXICO...GUATEMALA AND WRN GUATEMALA DRIVEN BY A JET STREAM BRANCH LOCATED TO THE E OF THE FAR ERN TROUGH MENTIONED ABOVE NEWD TO ACROSS SE MEXICO AND WRN GUATEMALA. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS SE OF THE TROUGH AXIS TO THE ITCZ ARE ENHANCED MAINLY BY DIFFLUENCE OCCURRING E OF THE TROUGH. SCATTERED SHOWERS AND TSTMS ARE QUICKLY DEVELOPING OVER THE MUCH OF THE INTERIOR PORTIONS OF CENTRAL AMERICA SUPPORTED BY BROAD/MID UPPER LEVEL RIDGING LOCATED TO THE E OF THE TROUGH WITH A MEAN RIDGE AXIS NW TO SE ALONG THE SPINE OF CENTRAL AMERICA SE TO A SMALL ANTICYCLONE OVER NW COAST OF COLOMBIA. DIFFLUENCE NOTED SW OF THE RIDGE IS ALSO HELPING TO SUSTAIN ITCZ CONVECTION BETWEEN 89W-95W. THE CYCLONIC CIRCULATION NEAR 17N135W WILL MOVE NW THROUGH THE NEXT 48 HRS IN A RELATIVELY WEAK UPPER FLOW ENVIRONMENT AS IT GRADUALLY NEARS A DEEP LAYER TROUGH APPROACHING THE NW CORNER OF THE AREA. A WEAK MID/UPPER LEVEL TROUGH EXTENDS FROM JUST S OF THE JET STREAM NEAR 9N132W SE TO 5N125W THEN BECOMES VERY NARROW TO NEAR 1N121W. MID/UPPER LEVEL RIDGING IS TO THE SW OF THE TROUGH. ITCZ CONVECTION IS RATHER CLUSTERED ALONG AND SE OF THE TROUGH FROM 6N TO 10N BETWEEN 125W AND 132W. SPURTS OF SCATTERED THIN HIGH CIRRUS CLOUDS MOVING EWD ARE ALONG 32N DUE TO A SERIES OF UPPER LEVEL DISTURBANCES N OF THE AREA IN FAST ZONAL FLOW CONTINUING TO SPIN OFF A LARGE CYCLONIC VORTEX OVER THE GULF OF ALASKA. AT THE SURFACE...A 1022 MB HIGH CENTER IS ANALYZED NEAR 25N133W WITH A RIDGE SE TO NEAR 18N116W. THE HIGH IS FORECAST TO REMAIN STATIONARY THROUGH THE NEXT 24-48 HRS KEEPING STRONG FRONTAL SYSTEMS WITH ASSOCIATED MODERATE TO STRONG SW WINDS TO THE N OF THE DISCUSSION AREA. A TIGHT PRES GRADIENT OVER THE FAR NE PART OF THE AREA BETWEEN THE HIGH AND LOW PRES OVER THE WRN U.S. WILL SUPPORT NW 20-25 KT WINDS ALONG THE BAJA CALIFORNIA COAST W TO NEAR 122W THROUGH THE NEXT 48 HRS. S OF THE HIGH CENTER NEAR 25N133W...THE PRES GRADIENT WILL MAINTAIN NE-E WINDS OF 20 KT THROUGH THE NEXT 48W W OF ABOUT 122W. A LATE SEASON LARGE NW SWELL TRAIN CONSISTING OF SEA HEIGHTS IN THE 8-13 FT RANGE WITH WAVE PERIODS OF 12-13 SECONDS IS FORECAST TO MOVE INTO THE FAR NW WATERS LATE MON PER LATEST WAVE MODEL GUIDANCE. $$ AGUIRRE