000 AXPZ20 KNHC 221608 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE APR 22 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 05N78W 06N90W 04N105W 04N110W 06N121W 06N130W 05N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 03N-08N BETWEEN 84W-89W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N OF THE AXIS BETWEEN 121W-124W. ...DISCUSSION... W OF 115W... A DEEP-LAYERED TROUGH MOVING EWD 25 KT ENTERS THE AREA THROUGH 32N132W...AND EXTENDS SW TO 27N136W AND TO W OF THE AREA AT 25N140W. THE TROUGH IS FOLLOWED BY MID/UPPER RIDGING BUILDING EWD INTO THE NW PORTION OF THE AREA. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE WITHIN 120 NM EITHER SIDE OF LINE 31N116W TO 28N125W TO 26N132W TO 25N140W AS A RESULT OF CONFLUENT NW FLOW INTO THE TROUGH. A VERY PRONOUNCED SUBTROPICAL JET STREAM BRANCH ENTERS THE REGION THROUGH 22N140W AND STRETCHES THROUGH 24N130W TO 27N120W AND CONTINUES NEWD TO ACROSS BAJA CALIFORNIA AND NRN MEXICO...AND AS FAR E AS THE WRN GULF OF MEXICO. THIS JET STREAM EXTENDS AS FAR W AS TO NEAR THE BIG ISLAND OF HAWAII. RIPPLES OF ENERGY IN THE FORM OF SHORT WAVE TROUGHS ARE RAPIDLY PROGRESSING EWD ALONG THE JET STREAM. SATELLITE-DERIVED WINDS ARE INDICATED TO BE IN THE RANGE OF 70-100 KT IN THE JET CORE REGION LOCATED ROUGHLY FROM 19N-24N BETWEEN 121W-128W. BROAD ANTICYCLONIC FLOW COVERS THE AREA TO THE SE OF THE ABOVE MENTIONED JET E OF ABOUT 137W WITH A MEAN CENTER NEAR 8N123W. EXTENSIVE UPPER LEVEL MOISTURE IN THE FORM OF HIGH CIRRUS CLOUDS CONTINUES TO BE ADVECTED BY THE JET STREAM NEWD TOWARDS MUCH OF BAJA CALIFORNIA AND...NRN MEXICO AND INTO THE NRN GULF OF MEXICO. AT THE SURFACE...A 1023 MB HIGH IS ANALYZED JUST W OF THE REGION NEAR 27N141W WITH A RIDGE EXTENDING SEWD THROUGH 26N129W TO NEAR 23N119W. HIGH PRES COVERS THE AREA N OF 14N W OF 115W. A SURFACE TROUGH MOVING W 15 KT IS ALONG 122W FROM 2N-9N. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM E OF THE TROUGH. GLOBAL MODELS SUGGEST THAT WEAK SURFACE LOW PRES MAY FORM ON OR NEAR THE TROUGH DURING THE NEXT 12-24 HOURS AS IT REMAINS UNDER THE INFLUENCE OF THE MID/UPPER LEVEL ANTICYCLONE NEAR 8N123W. PATCHES OF SCATTERED TO BROKEN MOSTLY STRATOCUMULUS CLOUDS MOVING SW WITH ISOLATED SHOWERS ARE NOTED NW OF A LINE FROM 12N140W TO 14N127W TO 15N115W. E OF 115W... A CUT-OFF MID TO UPPER LEVEL CYCLONIC CIRCULATION IS IDENTIFIED TO BE JUST ALONG THE EQUATOR NEAR 102W. TO ITS E...THE UPPER LEVEL FLOW BECOMES DIFFLUENT AND IS AIDING IN THE DEVELOPMENT OF ITCZ-RELATED CONVECTION WITHIN 120 NM N AND NE OF ITS CENTER. A QUIKSCAT PASS FROM 13 UTC THIS MORNING HINTED AT POSSIBLE WEAK LOW PRES IN THE VICINITY OF THE ITCZ NEAR 5N96W. A SHIP OBSERVATION WITH CALLER ID...A8IY8 NEAR 4N96W AT 12 UTC... INDICATED A W WIND OF 10 KT WITH A PRES OF 1006 MB. FIRST VISIBLE SATELLITE IMAGERY FROM THIS MORNING IS SHOWING SOME CYCLONIC TURNING TO LOW LEVEL CLOUD MOTION S OF THE ITCZ BETWEEN 93W-103W. GLOBAL MODELS ARE CONSISTENT IN HANGING ON TO LOW PRES OVER THIS SAME AREA THROUGH THE NEXT FEW DAYS. WITH THE PRES GRADIENT OVER THIS AREA BEING RATHER WEAK AND WITH VERY GOOD CONVERGENCE CONTINUING ALONG THE ITCZ...EXPECT BURSTS OF MODERATE TO STRONG CONVECTION TO BE SEEN ALONG AND NEAR THE ITCZ E OF ABOUT 96W THROUGH THE END OF THE WEEK. MODERATE SUBSIDENCE IS NOTED OVER JUST ABOUT THE ENTIRE AREA OUTSIDE THE ITCZ. A MID/UPPER LEVEL RIDGE RUNS FROM COLOMBIA NW TO ACROSS COSTA RICA. MID/UPPER LEVEL RIDGING COVERS ALL OF CENTRAL AMERICA...SE MEXICO AND NW COLOMBIA WITH ZONAL FLOW OVER JUST ABOUT THE ENTIRE COUNTRY OF MEXICO WHERE CONVECTION THERE REMAINS NON-EXISTENT AS DRY CONDITIONS PREVAIL. ONLY ISOLATED SHOWERS AND TSTMS ARE SEEN ALONG AND WITHIN 60-100 NM OF THE COASTS OF COSTA RICA AND PANAMA AT THIS TIME. A BATCH OF SCATTERED SHOWERS AND TSTMS DEVELOPED THIS MORNING OVER THE SE COAST OF GUATEMALA AHEAD OF A WEAK MID/UPPER LEVEL TROUGH MOVING E 15-20 KT OVER SE MEXICO AND THE GULF OF TEHUANTEPEC. $$ AGUIRRE