000 AXPZ20 KNHC 091605 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU APR 09 2015 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 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... ITCZ AXIS EXTENDS FROM 02N94W TO 03N111W TO 03N125W TO 03N140W. SCATTERED STRONG CONVECTION IS WITHIN 150 NM N OF ITCZ BETWEEN 133W-136W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM N OF ITCZ BETWEEN 105W-110W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N OF ITCZ BETWEEN 95W-101W...AND WITHIN 60 NM N OF ITCZ BETWEEN 104W-105W. ...DISCUSSION... ALOFT... A RATHER VIGOROUS AND LARGE SPRING TIME MID/UPPER LEVEL TROUGH EXTENDS FROM A POTENT UPPER LOW LOCATED N OF THE AREA AT 36N136W SW TO 32N136W TO WELL BEYOND THE AREA AT 27N140W. CYCLONIC FLOW IS PRESENT N OF 24N. A MID-LEVEL SHORTWAVE TROUGH LIFTING QUICKLY NEWD IS JUST N OF THE FAR NE PORTION. TO THE SE AND S OF THE OBSERVED CYCLONIC FLOW...BROAD RIDGING COVERS THE AREA WITH THE PARENT ANTICYCLONE NEAR 07N125W. A RIDGE EXTENDS FROM THE ANTICYCLONE NEWD TO 15N93W TO ACROSS CENTRAL MEXICO. A JET STREAM BETWEEN THE BROAD CYCLONIC FLOW AND RIDGING ENTERS THE REGION THROUGH 20N140W...AND CONTINUES ENE TO 23N128W TO ACROSS NORTHERN BAJA CALIFORNIA AND TO THE SW U.S. AMPLE MOISTURE IN THE FORM OF BROKEN TO OVERCAST MID/UPPER CLOUDS IS BEING ADVECTED NEWD ALONG AND WITHIN 450 NM SE OF THE JET STREAM BRANCH. SCATTERED SHOWERS ARE POSSIBLE FROM 21N-24N BETWEEN 111W -116W. THE UPPER LOW WILL CUT-OFF FROM THE TROUGH...AND MOVE INTO THE FAR NORTHERN PORTION ON FRI FROM 125W-134W. AT THE SURFACE...A WEAK 1019 MB HIGH IS NEAR 29N125W WITH A RIDGE EXTENDING SEWD TO NEAR 16N115W. HIGH PRES COVERS THE AREA N OF 18N W OF 115W. A COLD FRONT HAS ENTERED THE FAR NW WATERS...AND AT 12 UTC IS ANALYZED FROM A 1007 MB LOW N OF THE AREA AT 27N135W 1007 MB SSW TO 32N136W TO SW OF THE AREA AT 29N140W. INSTABILITY ALOFT IN COLD AIR ADVECTION IS PRODUCING SCATTERED SHOWERS AND WEAK ISOLATED TSTMS NW OF THE FRONT. SIMILAR ACTIVITY IS POSSIBLE 300 NM E OF THE FRONT N OF 28N. THE COLD FRONT IS FORECAST TO REACH FROM 32N130W TO 26N140W LATE TONIGHT...WITH SW 20-25 KT N OF 28N E OF FRONT TO 128W. N OF 29N W OF FRONT WINDS WILL BE NW AT AROUND 20 KT WITH SEAS 8-10 FT IN NW SWELL. BY EARLY ON FRI...THE COLD FRONT WILL BE ALONG A POSITION FROM 32N128W TO 27N131W 25N140W. THE SW 20-25 KT WINDS E OF THE FRONT WILL EXPAND SOME N OF 27N WITH SEAS TO 8 FT. THE PRES GRADIENT N OF THE FRONT WILL TIGHTEN AS THE ASSOCIATED DROPS SE...AND STRONG HIGH PRES IN ITS WAKE BUILDS SEWD. THE RESULTANT PRES GRADIENT WILL NW 20-25 KT WINDS N OF 29N BETWEEN 132W-136W WITH SEAS 9-12 FT IN NW SWELL. BY EARLY FRI NIGHT...THE LOW PRES WILL BE WEAKENING NEAR 32N131W AS 1011 MB WITH THE COLD FRONT FROM 30N127W TO 26N131W THEN WEAKENING STATIONARY FRONT TO 24N140W. SW WINDS OF 20-25 KT E OF THE FRONT WILL BE DIMINISHING IN COVERING...BUT NW-N 20-25 KT WINDS BEHIND IT N OF 29N WILL CONTINUE BETWEEN 132W-137W WITH SEAS 9-14 FT PRIMARILY IN NW SWELL. BY EARLY SAT...THE DISSIPATING LOW PRES IS FORECAST TO BE NEAR 29N127W WITH A PRES OF AROUND 1013 MB. THE WEAKENING COLD FRONT WILL EXTEND FROM THE LOW TO 25N125W TO 25N130W WITH SEAS SUBSIDING TO 8-10 FT PRIMARILY IN NW SWELL N OF 24N AND W OF A LINE FROM 20N125W TO 24N131W. A WEAK TROUGH ALONG 135W FROM 04N-09N IS ATTENDED BY SMALL CLUSTERS OF SCATTERED MODERATE/ISOALTED STRONG CONVECTION WITHIN 60 NM W OF AND 180 NM E OF IT. THE TROUGH SHOULD GRADUALLY DAMPEN OUT AS IT CONTINUES WESTWARD OVER THE 24-36 HOURS. GAP WINDS... GULF OF PAPAGAYO...NE 20 TO 25 KT WINDS ARE FORECAST TO DIMINISH TO 15-20 KT BY EARLY THIS EVENING...THEN START UP AGAIN AROUND DAYBREAK FRI AND DIMINISH AGAIN TO 15-20 KT BY EARLY FRI EVENING. SEAS TO 8 FT ARE FORECAST TO SUBSIDE TO LESS THAN 8 FT BY EARLY THIS EVENING...AND BUILD TO 9 FT FRI MORNING BEFORE SUBSIDING TO LESS THAN 8 FT EARLY FRI EVENING. GULF OF CALIFORNIA... NW WINDS 20 TO 25 KNOTS WITH WAVEHEIGHTS LESS THAN 8 FT WILL DEVELOP FRI NIGHT...THEN DIMINISH EARLY SAT. $$ AGUIRRE