000 AXPZ20 KNHC 191914 AAA TWDEP TROPICAL WEATHER DISCUSSION...UPDATED NWS NATIONAL HURRICANE CENTER MIAMI FL 1914 UTC THU FEB 19 2015 UPDATED ITZC SECTION 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1900 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...A VERY TIGHT PRES GRADIENT BETWEEN HIGH PRES ACROSS THE EASTERN U.S. EXTENDING SW INTO THE WESTERN AND SOUTHEASTERN MEXICO..AND RELATIVELY LOW PRES FARTHER S IN THE DEEP TROPICS IS SUPPORTING PERSISTENT GALE FORCE WINDS ACROSS THE GULF OF TEHUANTEPEC. MAXIMUM SUSTAINED WINDS OF 40 KT SHOULD CONTINUE UNTIL LATE THIS MORNING OR EARLY THIS AFTERNOON AS THE PRES GRADIENT STARTS TO RELAX AFTER PAST THE PERIOD OF PEAK NOCTURNAL DRAINAGE FLOW. MAXIMUM SEAS OF AROUND 14 FT WILL LOWER SLIGHTLY EARLY THIS AFTERNOON. AFTER DIMINISHING TO MINIMAL GALE FORCE THIS AFTERNOON...THE WINDS WILL PULSE AGAIN TO 40 KT WITH THE NOCTURNAL DRAINAGE FLOW LATE TONIGHT THROUGH EARLY SAT BEFORE DIMINISHING BELOW GALE FORCE BY MIDDAY ON SAT. SEAS WILL SUBSIDE TO A MAXIMUM OF AROUND 10 FT IN THE GULF OF TEHUANTEPEC BY THE END OF THE FORECAST PERIOD ON SUN MORNING. AT THAT TIME ...AN AREA OF FRESH NE TO E WINDS IS FORECAST FROM 04N-08N BETWEEN 99W AND 125W WITH SEAS OF 8-10 FT. WINDS ARE EXPECTED TO BE 20 KT OR LESS ELSEWHERE FROM 04N-12N BETWEEN 94W AND 107W WITH SEAS OF 8-10 FT IN MIXED NE AND NW SWELL. GULF OF PAPAGAYO GALE WARNING...THE SAME STRONG RIDGE AFFECTING THE GULF OF MEXICO IS ALSO PRODUCING A TIGHT PRES GRADIENT ACROSS CENTRAL AMERICA...AND INITIATED STRONG TO GALE FORCE NE WINDS ACROSS THE GULF OF PAPAGAYO LAST NIGHT AIDED BY THE NOCTURNAL MAXIMUM OF DRAINAGE FLOW OFF THE COAST. THESE WINDS WILL DIMINISH TO 25-30 KT BY EARLY THIS AFTERNOON WITH SEAS OF 9-12 FT. WINDS WILL THEN PULSE TONIGHT...WITH MAXIMUM SUSTAINED WINDS REACHING GALE FORCE STARTING AT AROUND 03Z...AND CONTINUE THROUGH MIDDAY SAT BEFORE DIMINISHING TO 20-30 KT WITH SEAS OF 8- 11 FT. A LONG FETCH OF FRESH TO STRONG NE WINDS WILL EXTEND SW OF PAPAGAYO TO NEAR 94W THROUGH SAT AFTERNOON. RESULTANT SWELL FROM THE THIS EVENT WILL MERGE WITH SWELL PRODUCED FROM THE GULF OF TEHUANTEPEC EVENT AS DESCRIBED ABOVE. ...INTERTROPICAL CONVERGENCE ZONE...UPDATED THE ITCZ EXTENDS FROM 04N88W TO 01N104W TO 01N113W TO 04N125W. IT RESUMES AT 04N130W TO BEYOND 04N140W. NO SIGNIFICANT CONVECTION NOTED. ...DISCUSSION... A WEAKENING COLD FRONT STRETCHES FROM NW MEXICO SW TO BAJA CALIFORNIA AT LORETO...THEN BECOMES ILL-DEFINED SW TO 26N114W. WITH THE UPPER LEVEL SUPPORT NO LONGER FAVORABLE TO SUPPORT FURTHER SOUTHWARD PROGRESSION OF THE FRONT...THE FRONT WILL BECOME DIFFUSE THIS AFTERNOON. NW SWELL GENERATED BEHIND THIS FRONT WILL BRING SEAS OVER 8 FT TO MUCH OF THE NW HALF OF THE AREA...INCLUDING ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA THROUGH SAT EVENING. SEAS JUST OFF THE BAJA CALIFORNIA NORTE COAST WILL BE AS HIGH AS 11 FT IN THE WATERS JUST OFFSHORE THIS AFTERNOON AND TONIGHT AND EARLY SAT BEFORE BEGINNING TO SUBSIDE. WEAK HIGH PRES IS BUILDING SE ACROSS THE NW AND CENTRAL WATERS ...EXCEPT IN THE FAR NW CORNER WHERE A COLD FRONT HAS ENTERED THE REGION ALONG A POSITION FROM 32N134W TO 29N140W. AN ASCAT PASS FROM 0528 UTC SHOWED STRONG TO GALE FORCE WINDS NW OF THE DISCUSSION RELATED TO THE FRONT WITH GENTLE TO MODERATE NW-N WINDS BEHIND THE FRONT S OF 32N...AND MOSTLY GENTLE W-SW WINDS AHEAD OF IT TO NEAR 130W. THIS FRONT IS FORECAST TO WEAKEN RATHER QUICKLY THROUGH TONIGHT AS STRONGER HIGH PRES MATERIALIZES OVER THE N CENTRAL PORTION OF THE AREA. ANOTHER COLD FRONT WILL APPROACH THE FAR NW WATERS LATE SAT AFTERNOON...THEN STALL SAT NIGHT AND LIFT BACK N AS A WARM FRONT ON SUN IN RESPONSE TO DEEPENING LOW PRES NW OF THE REGION THAT TRACKS TO THE NE. SCATTEROMETER DATA FROM LATE LAST NIGHT REVEALED WEAKER TRADE WINDS...IN THE 15-20 KT RANGE S OF 14N. THESE TRADES ARE FORECAST TO INCREASE TO SAT AND SUN REACHING THE FRESH RANGE WHILE EXPANDING TO THE N AND E AS HIGH PRES CENTERED JUST N OF THE AREA BUILDS S WHILE INTENSIFYING. SEAS WITHIN THESE TRADES ARE FORECAST TO BUILD TO AROUND 9 FT SAT. GAP WINDS... GULF OF PANAMA... STRONG RIDGING OVER THE WESTERN CARIBBEAN HAS INITIATED FRESH TO STRONG N-NE WINDS THROUGH THE GULF OF PANAMA WITH SEAS OF 8-10 FT. THESE WINDS WILL CHANGE LITTLE INTO EARLY SAT...THEN DIMINISH TO 20-25 KT EARLY SAT AFTERNOON AND CONTINUE THROUGH EARLY SUN. $$ AGUIRRE