000 AXPZ20 KNHC 172145 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN NOV 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 09N84W TO 06N108W THEN ITCZ TO 11N125W TO BEYOND 07N140W. SCATTERED MODERATE CONVECTION WITHIN 60 NM N OF ITCZ AXIS W OF 128W. ...DISCUSSION... UPPER LEVEL CYCLONE AT 31N116W HAS TROUGH EXTEND SW TO 07N140W. VERY DRY AIR MASS W OF TROUGH AXIS PRECLUDE ANY SIGNIFICANT CONVECTION. STRONG SHORTWAVE SLIDING ON W SIDE OF TROUGH BRINGS MORE ENERGY INTO SCENE WITH NEW CUTOFF CYCLONE EXPECTED TO FORM OFF BAJA CALIFORNIA W COAST. STILL...DUE TO EXTREME DRYNESS OF THE AIR MASS LIKELIHOOD OF SEVERE OR COPIOUS CONVECTION IS LIMITED. SE OF UPPER LEVEL TROUGH...55 KT SW JET CORE ADVECTS SIGNIFICANT AMOUNTS OF TROPICAL MOISTURE ...MAINLY ITCZ CONVECTIVE DEBRIS... NORTHEASTWARD TOWARDS BAJA CALIFORNIA AND NORTHWESTERN MEXICO. EXCEPT FOR REGION N OF 04N E OF 86W...REMAINDER OF BASIN REMAINS QUITE DRY AND STABLE. ...ELSEWHERE AT THE LOWER LEVELS... WEAKENING HIGH PRES 1021 MB AT 32N135W HAS FLATTENED PRES GRADIENT AND DIMINISHED NE TRADES TO A MODERATE BREEZE WITH SEAS BELOW 8 FT. IN SE CORNER OF E PAC...STRONG SURFACE WIND CONVERGENCE HAS PROMPTED SCATTERED MODERATE TO STRONG CONVECTION N OF 04N E OF 82W BUT LACK OF SIGNIFICANT VORTICITY DOES NOT SUPPORT ANY LONG LASTING EFFECTS OF THE THUNDERSTORM BURST. $$ ...LOOKING AHEAD... COLD FRONT APPROACHES NW CORNER OF BASIN WITH ABUNDANT MOISTURE AVAILABLE FOR WESTERN SIDE OF ITCZ TO PRODUCE SOME CONVECTION. HIGH PRES BEHIND COLD FRONT LIKELY TO BRING FRESH TO STRONG NE TRADES BACK TO WESTERN HALF OF BASIN WITH SEAS BUILDING TO 9-11 FT BY MID-TO-LATE IN THE WEEK. $$ WALLY BARNES