000 AXPZ20 KNHC 190905 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE FEB 19 2013 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0930 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH NOT DISCERNIBLE FOR 0600 UTC ANALYSIS. THE ITCZ EXTENDS FROM 04N95W TO 09N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 120 NM N OF THE ITCZ W OF 135W. ...DISCUSSION... THE MID TO UPPER LEVEL PATTERN N OF 20N REMAINS HIGHLY AMPLIFIED OVER THE NE PACIFIC. AN UPPER TROUGH EXTENDS FROM NORTHERN CALIFORNIA TO 30N130W...WEST OF REX BLOCK PATTERN ALONG 155W CONSISTING OF AN DEEP LAYER RIDGE N OF STATIONARY UPPER LOW CENTERED NE OF THE BIG ISLAND OF HAWAII NEAR 23N153W. A VIGOROUS UPPER DISTURBANCE N OF THE AREA NEAR 45N129W IS MOVING SE INTO THE BASE OF THE UPPER TROUGH...AND WILL MOVE ACROSS SOUTHERN CALIFORNIA BY TUE NIGHT SUPPORTING THE PUSH OF A COLD FRONT THROUGH NORTHERN BAJA AND THE NORTHERN GULF OF CALIFORNIA THROUGH MID WEEK. THE GFS REMAINS CONSISTENT SHOWING A SOMEWHAT DEEPER PRES WITH THIS FEATURE THAN DOES THE ECMWF...ALTHOUGH DIFFERENCES IN POSITION AND TIMING REMAIN MINIMAL. THE COLD FRONT WILL REACH FROM SOUTHERN CALIFORNIA ACROSS NORTHERN BAJA TO NEAR 25N125W BY EARLY WED...FOLLOWED BY FRESH TO STRONG NW TO N WINDS AND SEAS OF 9 TO 14 FT. FRESH TO STRONG WESTERLY FLOW WILL ALSO FOLLOW THE FRONT ACROSS THE NORTHERN PORTIONS OF THE GULF OF CALIFORNIA N OF 29N WED. A 1035 MB SURFACE HIGH CENTERED NEAR 35N150W UNDER THE MID TO UPPER RIDGE N OF HAWAII WILL SHIFT E...BROADENING AN AREA OF FRESH TO STRONG TRADE WINDS LOCATED GENERALLY N OF 08N AND W OF 125W BY MID WEEK. DIVERGENT FLOW ALOFT IS ALLOWING MODEST CONVECTION TO PERSIST WITHIN 120 NM N OF THE ITCZ W OF 135W. LOOKING AHEAD TO LATE IN THE WEEK...THERE IS GOOD AGREEMENT AMONG VARIOUS MODELS INDICATING THE REX BLOCK PATTERN WILL WEAKEN TUE INTO WED AS ANOTHER MID/UPPER LEVEL SHORT WAVE TROUGH MIGRATES N OF THE RIDGE THEN DIGS SE INTO THE MAIN TROUGH OVER THE WEST COAST WED INTO THU...BRINGING ANOTHER ROUND OF NW WINDS N OF 20N E OF 130W. THE GFS AGAIN REMAINS STRONGER THAN THE ECMWF AND UKMET...BUT MODEL TIMING AND POSITION ARE CLOSE. GAP WINDS... A 0300 UTC ASCAT PASS INDICATED FRESH TO STRONG GAP WINDS THROUGH THE GULF OF PAPAGAYO...ALTHOUGH NOT SO MUCH THROUGH THE GULF OF FONSECA. OTHER SCATTEROMETER DATA INDICATED ONLY MODERATE TO FRESH WINDS THROUGH THE GULF OF PANAMA AND TEHUANTEPEC. FRESH TO STRONG WINDS WILL CONTINUE TO PULSE ACROSS THE GULF OF PAPAGAYO THROUGH THE REMAINDER OF THE WEEK...WITH STRONGEST WINDS DURING THE OVERNIGHT AND EARLY MORNING HOURS. A LONG PLUME OF FRESH E WINDS ALONG WITH SEAS OF UP TO 9 FT IN E SWELL WILL PERSIST DOWNWIND OF PAPAGAYO TO AROUND 110W THROUGH TUE. PRES OVER THE EASTERN PACIFIC WILL LOWER SLIGHTLY TUE...ENOUGH TO PRODUCE A PRES GRADIENT ACROSS THE ISTHMUS OF TEHUANTEPEC TO SUPPORT A BRIEF PULSE OF 20 TO 25 KT GAP WINDS EARLY WED. $$ CHRISTENSEN