000 AXPZ20 KNHC 200911 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN MAR 20 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 0630 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 05N89W TO 1010 MB LOW PRES NEAR 01N98W TO 04N110W TO 05N127W TO 03N140W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM N OF THE ITCZ AXIS BETWEEN 90W AND 97W. ...DISCUSSION... A VIGOROUS DEEP LAYERED LOW NORTH OF THE AREA NEAR 38N125W EXTENDS A BROAD UPPER TROUGH INTO THE FORECAST AREA NEAR 32N124W THROUGH 19N134W AND EXITS THE AREA AT 19N140W. A 70-90 KT SOUTHWESTERLY UPPER JET LIES ON THE EASTERN SIDE OF THE TROUGH N OF 20N. THE COINCIDENT DEEP LAYER WEST-SOUTHWESTERLY JET IS PUMPING ABUNDANT MOISTURE INTO CALIFORNIA AT THE MOMENT...WITH MODERATE RAIN OVER MUCH OF THE STATE NORTH OF LONG BEACH AND WEST OF THE SIERRA NEVADA. THE SURFACE COLD FRONT ASSOCIATED WITH THE DEEP LAYER TROUGH HAS MOVED INTO FAR NORTHERN WATERS FROM 30N130W TO 29N135W TO 30N140W. STRONG COLD AIR ADVECTION BEHIND THE FRONT IS IMPLIED BY THE CUMULUS FIELD SEEN THERE IN INFRARED IMAGERY. THE ASCAT PASS AT 0506 UTC SHOWED WINDS JUST BELOW GALE FORCE N OF 29N BETWEEN 126W AND 129W. WINDS SHOULD HAVE INTENSIFIED SLIGHTLY SINCE THEN...SO A GALE WARNING HAS BEEN ISSUED AND IS IN EFFECT FOR THE SW TO W WINDS AHEAD OF THE FRONT UNTIL THIS EVENING. THE NW SWELL USHERED IN BY THIS FRONT WILL SLOWLY BUILD TO AS HIGH AS 18 FT BY MON MORNING. HIGH PRES PREVAILS S OF THE FRONT TO 12N AND W OF 113W. FRESH TO STRONG TRADE WINDS LIE S OF THE RIDGE AXIS FROM 08N TO 16N W OF 125W ACCORDING TO THE 0642 AND 0502 UTC ASCAT PASSES. THE RIDGE WILL SHIFT SOUTHWARD AND WEAKEN CONSIDERABLY AS THE COLD FRONT MOVES THROUGH N WATERS TODAY AND MON. THIS WILL ALLOW THE TRADES TO DIMINISH A NOTCH AND SHRINK IN AREA. BY TUE MORNING...THE RIDGE WILL REBUILD OVER NW WATERS IN THE WAKE OF THE DISSIPATED FRONT AND TRADES OVER WESTERN WATERS WILL EXPAND NORTHWARD IN RESPONSE. AN UPPER RIDGE AXIS EXTENDS FROM A BROAD ANTICYCLONE LOCATED NEAR 19N100W TO 10N126W. WATER VAPOR IMAGERY SHOWS DRY AIR ALOFT OVER MUCH OF THE AREA S OF 20N BETWEEN 85W AND 105W IN THE VICINITY OF THE ANTICYCLONE. MOST OF THIS AREA IS VOID OF DEEP CONVECTION WITH THE EXCEPTION OF IMMEDIATELY N OF THE ITCZ FROM 90W-97W WHERE LOW TO MID LEVEL MOISTURE IS POOLED AND DIFFLUENCE ALOFT BETWEEN THE SOUTHERN EDGE OF THE ANTICYCLONIC CIRCULATION AND A 25 KT-45 KT SOUTHWESTERLY UPPER JET FROM 04N92W TO 12N84W IS ENHANCING VERTICAL MOTION. SEE THE ITCZ SECTION FOR DETAILS. FARTHER SE...A 1009 MB SURFACE LOW ALONG THE COAST OF COLOMBIA NEAR 04N78W IS EXPECTED TO MOVE LITTLE OVER THE NEXT 48 HOURS. NUMEROUS MODERATE TO STRONG CONVECTION LIES WITHIN 90 NM OF THE COAST OF COLOMBIA FROM 03N TO 07N NEAR THE LOW. THIS AREA COINCIDES WITH THE HIGHEST PRECIPITABLE WATER VALUES OVER THE FORECAST AREA AND BROAD DIFFLUENCE BETWEEN RIDGE AXES N AND S OF THE EQUATOR. GAP WINDS... GULF OF CALIFORNIA...SW WINDS IN THE NORTHERN GULF OF CALIFORNIA ARE EXPECTED TO INCREASE ABOVE ADVISORY CRITERIA THIS EVENING AHEAD OF THE PREVIOUSLY MENTIONED STRONG COLD FRONT. THE FRONT WILL MOVE INTO THE AREA LATE MON AND QUICKLY DISSIPATE...BUT 20 KT SW WINDS ARE EXPECTED TO LINGER THERE UNTIL TUE MORNING. GULF OF TEHUANTEPEC...FRESH TO STRONG N TO NE WINDS ARE EXPECTED TO CONTINUE OVER THE NEXT TWO DAYS WITH A DIURNAL MAXIMUM COINCIDING WITH MORNING DRAINAGE FLOW THROUGH THE PASS. THE 0320 UTC ASCAT PASS CONFIRMED THESE CONDITIONS. GULF OF PAPAGAYO...A STRONG PRES GRADIENT BETWEEN HIGH PRES OVER CENTRAL AMERICA TO THE N AND LOW PRES ALONG THE W COAST OF COLOMBIA IS EXPECTED TO CONTINUE WITH LITTLE CHANGE OVER THE NEXT FEW DAYS. FRESH TO STRONG NE TO E WINDS WILL CONTINUE TO FUNNEL FROM THE CARIBBEAN THROUGH CENTRAL AMERICA THROUGH TUE MORNING. GULF OF PANAMA...PERSISTENT PRES GRADIENT BETWEEN THE LOW/TROUGH NEAR THE COAST OF COLOMBIA AND HIGH PRES OVER CENTRAL AMERICA WILL SUSTAIN N WINDS OF 20 KT WITH LITTLE CHANGE EXPECTED IN WINDS AND SEAS OVER THE NEXT TWO DAYS. $$ SCHAUER