000 AXPZ20 KNHC 230947 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT MAY 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... BROAD CYCLONIC CIRCULATION IS ANALYZED AS A 1008 MB SURFACE LOW NEAR 09N128W. SCATTERED MODERATE ISOLATED STRONG CONVECTION REMAINS UNORGANIZED WITHIN 270 NM EITHER SIDE OF A LINE FROM 13N120W TO 07N133W. THE GRADIENT N OF THE LOW AND S OF A SUBTROPICAL RIDGE IS MAINTAINING NE-E 20-25 KT WINDS ACROSS THE WATERS FROM 11-15N BETWEEN 125-130W WITH SEAS OF 9-11 FT. THE LOW HAS THE POTENTIAL TO BECOME A TROPICAL CYCLONE AS IT REACHES NEAR 12N131W LATE TONIGHT AND NEAR 14N135W ON SUN NIGHT. THE LOW...OR POSSIBLE TROPICAL CYCLONE...IS EXPECTED TO MOVE W THROUGH MOST OF NEXT WEEK WITH THE STRONG EASTERLY WINDS OVER THE N SEMICIRCLE. A 1008 MB LOW IS ANALYZED AT 07N138W WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 05N132W TO BEYOND 04N140W. ALTHOUGH E WINDS ARE ONLY 15-20 KT OVER THE N SEMICIRCLE OF THE LOW...THERE IS SOME POTENTIAL FOR TROPICAL CYCLONE FORMATION AS THE LOW REACHES NEAR 07N140W TONIGHT AND THEN CONTINUES W OF THE AREA ON SUN. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A LOW LEVEL TROUGH EXTENDS SW FROM THE PACIFIC COAST OF COSTA RICA AT 10N TO 07N96W WHERE SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS...THEN WIGGLES WNW TO 10N122W WHERE THE ITCZ IS INTERRUPTED BY THE BROAD CYCLONIC FLOW ASSOCIATED WITH TWO SURFACE LOWS PREVIOUSLY MENTIONED. EXCEPT AS ALREADY MENTIONED IN ASSOCIATION WITH THE SURFACE LOWS...SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 300 NM EITHER SIDE OF A LINE FROM 04N87W TO 05N110W TO 10N117W. A 1009 MB SURFACE LOW IS ANALYZED OVER NORTHERN COLOMBIA AT 09N74W WITH A TROUGH EXTENDING SW FROM 05N77W TO 03N82W... WITH SCATTERED MODERATE CONVECTION FLARING WITHIN 150 NM OF THE TROUGH AXIS. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 180 NM OF THE COAST OF CENTRAL AMERICA AND MEXICO FROM 90-100W. ...DISCUSSION... AN UPPER CYCLONE OVER SOUTHERN NEVADA TRAILS AN UPPER TROUGH ACROSS THE DISCUSSION AREA FROM 32N115W TO 22N122W. AN UPPER ANTICYCLONE IS CENTERED OVER THE TROPICS NEAR 13N115W WITH AN UPPER RIDGE EXTENDING W TO BEYOND 13N140W. ADDITIONALLY A KELVIN WAVE IS SHIFTING E ACROSS THE WESTERN PORTION OF THE DISCUSSION AREA...AND COMBINES WITH THE UPPER DIFFLUENCE ALONG THE UPPER RIDGE TO ENHANCE THE CONVECTION NEAR THE TROPICAL SURFACE LOWS PREVIOUSLY DESCRIBED. SOME OF THE DEBRIS MOISTURE FROM THIS CONVECTION CONCENTRATES INTO A 660 NM WIDE TROPICAL PLUME THAT IS ADVECTED NE AHEAD OF THE PREVIOUSLY DESCRIBED UPPER TROUGH... AND ACROSS THE SOUTHERN GULF OF CALIFORNIA AND NORTHERN MEXICO...EVENTUALLY FEEDING INTO SIGNIFICANT CONVECTION OVER TEXAS. A SURFACE RIDGE EXTENDS FROM 32N133W TO 16N104W. TO THE NE OF THE RIDGE ARE NW WINDS AT 15-20 KT ALONG THE PACIFIC COAST OF THE BAJA PENINSULA WITH COMBINED SEAS OF 4-6 FT. THE GRADIENT WILL TIGHTEN SOME TONIGHT SUPPORTING 20-25 KT NW FLOW BRIEFLY ACROSS THE EPAC WATERS FROM 25-28N E OF 115W TO THE BAJA COAST. THE GRADIENT WILL ALSO INCREASE SW OF THE RIDGE...AND E OF A COLD FRONT MOVING THROUGH THE HAWAIIAN ISLANDS...WITH SE WINDS INCREASING TO 20-25 KT ACROSS THE DISCUSSION WATERS N OF 23N W OF 135W TONIGHT THROUGH SUN NIGHT...WITH SEAS BUILDING TO 7-10 FT. THE GRADIENT WILL RELAX ON MON AS THE WEAKENING FRONT MOVES INTO THE AREA ACCOMPANIED BY A SE-S-SW 15-20 KT WIND SHIFT AND MODERATE CONVECTION. LONG PERIOD SW SWELL AT 13-18 SECONDS OBSERVED ACROSS THE DISCUSSION AREA S OF 25N WILL CONTINUE N REACHING ALONG 32N TONIGHT AND CONTINUE THROUGH EARLY NEXT WEEK. GULF OF PAPAGAYO...EXPECT A BRIEF NE-E 20-25 KT SURGE EARLY TODAY THAT WILL BUILD SEAS TO 8 FT. THESE ENHANCED SEAS WILL PROPAGATE W AND MIX WITH LONG PERIOD CROSS-EQUATORIAL SW SWELL ACROSS THE PACIFIC WATERS FROM 09-12N BETWEEN 88-93W TODAY AND SUBSIDE TO 5-7 FT TONIGHT. GULF OF TEHUANTEPEC...EXPECT A BRIEF SURGE OF 20-25 KT NORTHERLY WINDS AT SUNRISE TODAY. $$ NELSON