000 AXPZ20 KNHC 211018 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT FEB 21 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 0900 UTC. ...SPECIAL FEATURES... GALE WARNING...A DEVELOPING STORM SYSTEM LOCATED NW OF THE HAWAIIAN ISLANDS AND CENTERED NEAR 35N167W EARLY THIS MORNING WILL INTENSIFY RAPIDLY OVER THE NEXT 24 HOURS TO PRODUCE HURRICANE FORCE WINDS...AS IT MOVES EASTWARD...AND THEN BEGIN TO SHIFT NORTHEASTWARD AND CROSS 150W MON AFTERNOON THROUGH NIGHT AS IT WEAKENS VERY GRADUALLY. THIS VERY LARGE AND COMPLEX SYSTEM WILL DRAG A COLD FRONT INTO THE FAR NW CORNER OF THE DISCUSSION AREA OVERNIGHT MONDAY...WITH STRONG SOUTHERLY WINDS AHEAD OF THE FRONT EXPECTED TO INCREASE TO GALE FORCE ACROSS THE WATERS N OF 28N W OF 138W MONDAY EVENING. THIS GALE EVENT WILL BE SHORT LIVED AS THESE STRONG TO GALE FORCE WINDS LIFT OUT OF THE AREA TO THE N OVERNIGHT MONDAY. ADDITIONALLY...THIS POWERFUL SYSTEM WILL GENERATE EXTREMELY LARGE NW SWELL BEHIND THE COLD FRONT THAT WILL MOVE INTO THE NW WATERS MON NIGHT AND REACH ALONG 135W BY TUE MORNING. SEAS ARE EXPECTED TO BUILD IN EXCESS OF 20 FT ACROSS THE NW WATERS BY TUE MORNING AND PROPAGATE E AND SE ACROSS THE DISCUSSION AREA THROUGHOUT THE ENTIRE WORK WORK. VERY LARGE NW SWELL WILL STRONGLY IMPACT THE WEST COAST OF THE U.S. AND BAJA CALIFORNIA EARLY WED THROUGH THU. ...INTERTROPICAL CONVERGENCE ZONE... THE ITCZ EXTENDS FROM 04.5N90W TO 02.5N100W TO 01N120W TO 01.5N130WTO BEYOND 01.5N140W. ISOLATED TO WIDELY SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 150 NM N OF AXIS W OF 94W. ...DISCUSSION... THE UPPER LEVEL PATTERN OVER THE EASTERN AND CENTRAL NORTH PACIFIC IS BECOMING MORE AMPLIFIED. A 1025 MB HIGH PRES CENTER IS LOCATED JUST N OF THE AREA NEAR 31N127W. A RIDGE AXIS EXTENDS SW FROM THE HIGH TO THE SOUTHERN HAWAIIAN ISLANDS. TRADE WINDS HAVE INCREASED TO A FRESH TO STRONG BREEZE BETWEEN THE RIDGE AXIS AND THE ITCZ FROM 05N-11N W OF 120W. THIS HIGH IS EXPECTED TO BUILD OVER THE N WATERS TODAY AS THE RIDGE AXIS IS SHIFTED SOUTHEASTWARD BY DEEP TROUGHING BUILDING N OF HAWAII. THIS DEVELOPMENT WILL SHIFT AND EXPAND THE AREA OF TRADE WINDS NORTHEASTWARD INTO S CENTRAL WATERS TODAY. AT THE SAME TIME...THE PRES GRADIENT WILL BUILD OVER NW WATERS BETWEEN THE RIDGE AND A COLD FRONT W OF THE AREA...WITH A FRESH TO STRONG S- SE BREEZE EXPECTED OVER FAR NW WATERS BY THIS AFTERNOON. THE FRONT WILL SQUEEZE THE SUBTROPICAL HIGH NORTHWARD BY MON...WITH TRADE WINDS DIMINISHING AND WINDS INCREASING TO GALE FORCE OVER NW WATERS AS DESCRIBED ABOVE. SEAS ACROSS THE NW WATERS WILL BUILD TO 8-12 FT IN NW SWELL SUN NIGHT AND THEN INCREASE FURTHER ON MONDAY AS A NEW COLD FRONT APPROACHES FROM THE NW. GAP WINDS... GULF OF CALIFORNIA...N-NW WINDS WILL REACH A FRESH TO STRONG BREEZE FROM 23N-29N THIS EVENING AS HIGH PRES BUILDS OVER THE GREAT BASIN AND SURFACE PRESSURES FALL OVER CENTRAL MEXICO. THE TIGHTEST PRES GRADIENT WILL GRADUALLY SHIFT NORTHWARD IN THE GULF BY MON AFTERNOON...AND PERSIST THROUGH LATE MON. SEAS SHOULD BUILD TO 8 FT LATE MON IN THE SOUTH-CENTRAL PORTION OF THE GULF UNDER PERSISTENT LONG FETCH OF STRONG NW WINDS. GULF OF TEHUANTEPEC...THE PRES GRADIENT BETWEEN STRONG HIGH PRES TO THE NORTH AND RELATIVE LOW PRES FARTHER SOUTH IN THE DEEP TROPICS IS CONTINUING TO SUPPORT MAXIMUM SUSTAINED WINDS TO 30 KT IN THE GULF OF TEHUANTEPEC EARLY THIS MORNING. MAXIMUM SEAS OF 9-10 FT ARE EXPECTED THROUGH SUNRISE. THE PRES GRADIENT WILL WEAKEN THIS MORNING...AND WINDS WILL DROP OFF QUICKLY AFTER SUNRISE...DIMINISHING TO 20-25 KT BY NOON AND BELOW 20 KT BY SUNSET. THE NEXT STRONG GAP WIND EVENT HERE IS EXPECTED TO DEVELOP VERY QUICKLY WED AFTERNOON AND EVENING AS A STRONG COLD FRONT SWEEPS ACROSS THE GULF OF MEXICO. WINDS WILL REACH STRONG GALES WED NIGHT...WITH GLOBAL MODELS SUGGESTING THE POTENTIAL FOR STORM FORCE WINDS. GULF OF PAPAGAYO...A STRONG PRES GRADIENT BETWEEN HIGH PRES OVER THE NW CARIBBEAN AND LOWER PRES TO THE SW WILL CONTINUE TO DRIVE FUNNELING WINDS ACROSS NICARAGUA AND NORTHERN COSTA RICA INCLUDING INTO THE GULF OF PAPAGAYO. WINDS OF 20-30 KT CURRENTLY PREVAIL ACROSS THE REGION...AND WILL FOLLOW THE NORMAL DIURNAL TREND...AND DIMINISH TO A FRESH TO STRONG BREEZE LATE THIS AFTERNOON AND EVENING BEFORE NOCTURNAL DRAINAGE EFFECTS ENHANCE WINDS BACK TO AROUND 30 KT IN THE EARLY MORNING HOURS SUN. WINDS WILL DIMINISH TO A FRESH TO STRONG BREEZE MIDDAY SUN THROUGH SUN EVENING...INCREASE AGAIN TO 30 KT EARLY MON MORNING AND THEN DIMINISH TO AROUND 20 KT BY MIDDAY MON AS THE PRES GRADIENT ACROSS CENTRAL AMERICA SLACKENS. NORTHERLY SWELL FROM THE GULF OF TEHUANTEPEC HAS MIXED WITH THAT FROM THE GULF OF PAPAGAYO TO CREATE A LARGE SWATH OF SEAS IN THE 8-10 FT RANGE GENERALLY FROM 03N-11N BETWEEN 90W-110W. THESE MIXING SWELL CONDITIONS WILL PERSIST THROUGH EARLY MON AS NW SWELL CONTRIBUTES TO THE COMBINED SEAS HERE. THIS AREA WILL SHRINK WESTWARD MON AND SUBSIDE BELOW 8 FT BY MON EVENING. GULF OF PANAMA...STRONG RIDGING N OF THE AREA CONTINUES TO PRODUCE A TIGHT PRES GRADIENT ACROSS THE GULF OF PANAMA EARLY THIS MORNING...PRODUCING FRESH TO STRONG N-NE WINDS BLOWING ACROSS THE GULF AND DOWNWIND TO 05N81W...WITH SEAS 6 TO 9 FT. WINDS WILL DIMINISH DURING THIS AFTERNOON AND EVENING AS THE PRES GRADIENT WEAKENS ACROSS CENTRAL AMERICA. WINDS WILL BRIEFLY PULSE TO A BROAD AREA OF 25 KT IN THE AREA S-SW OF THE GULF OF PANAMA TO 05N81W OVERNIGHT TONIGHT BEFORE DIMINISHING TO 20 KT OR LESS DURING THE DAY MON. $$ STRIPLING