000 AXPZ20 KNHC 170347 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT JAN 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0230 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...STRONG NORTHERLY FLOW BETWEEN A COLD FRONT ACROSS THE N COAST OF YUCATAN PENINSULA... AND STRONG RIDGING ALONG THE EASTERN MEXICAN COAST CONTINUES TO FUNNEL THROUGH THE ISTHMUS OF TEHUANTEPEC AND ACROSS THE GULF OF TEHUANTEPEC. EARLY AFTERNOON ASCAT PASSES SHOWED WINDS CONTINUING IN 30 TO 40 KT RANGE ACROSS THE GULF OF TEHUANTEPEC...BUT WILL DIMINISH TO 30-35 KT EARLY OVERNIGHT... THEN FALL BELOW GALE FORCE SATURDAY MORNING AS THE RIDGING ACROSS THE WESTERN GULF OF MEXICO BEGINS TO WEAKEN. A SMALL POCKET OF FRESH TO STRONG NORTHERLY WINDS WILL PERSIST IN THE IMMEDIATE GULF OF TEHUANTEPEC THROUGH SUN MORNING. THE LATEST WAVE MODEL GUIDANCE INDICATES MAXIMUM SEAS AROUND 15 FT THIS EVENING THEN SUBSIDING TO 8-12 FT LATE TONIGHT INTO EARLY SAT...THEN TO 8-10 FT OVERNIGHT SAT INTO EARLY SUN. THE NEXT ROUND OF GALE FORCE WINDS IS EXPECTED TO START SUN AFTERNOON INTO MON MORNING. A GALE WARNING HAS JUST BEEN DISCONTINUED FOR A 1007 MB LOW PRESSURE CENTER NEAR 17.5N118.5W. EARLY AFTERNOON ASCAT PASSES SHOWED MINIMAL GALE FORCE WINDS OCCURRING WITHIN 120 NM ACROSS THE NE SEMICIRCLE...WHERE SEAS WERE 10 TO 13 FT...WHILE STRONG TRADEWINDS OCCURRING BETWEEN HIGH PRES TO THE N AND THE LOW WERE LOCATED WITHIN 150 NM SE QUADRANT AND 240 NM NW SEMICIRCLE. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 180 NM ACROSS THE N SEMICIRCLE OF THE LOW THIS EVENING...AND A DECREASING TREND IN CONVECTION HAS CONTINUED THROUGHOUT THE AFTERNOON AND EARLY EVENING HOURS. THIS LOW CENTER IS ASSOCIATED WITH MIDDLE TO UPPER LEVEL ENERGY NOTED ON WATER VAPOR IMAGERY WITHIN A BROAD DEEP LAYERED TROUGH BETWEEN 110W AND 130W. THIS TROUGHING ALOFT HAS CUT OFF A DEEP LAYER LOW NEAR 15N125W WHICH WILL DRIFT E-SE THROUGH EARLY NEXT WEEK. SATELLITE IMAGERY SUGGESTS THE LOW HAS ALREADY REACHED ITS PEAK INTENSITY...AND IS CURRENTLY BECOMING ELONGATED N-NW TO S-SE...AND GALE FORCE WINDS ASSOCIATED WITH THE LOW HAVE ENDED. HOWEVER...THE PRESSURE GRADIENT BETWEEN THE LOW AND THE FAIRLY STATIONARY SUBTROPICAL RIDGE TO THE N WILL BE STRONG ENOUGH TO SUPPORT 20-25 KT WINDS ON THE NORTHERN PERIPHERY OF THE LOW CENTER THROUGH SUN AS IT SHIFTS NW THEN W...MAINTAINING SEAS UP TO 12 FT TONIGHT AND TO 10 FT ON SAT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH AXIS EXTENDS FROM 06N75W TO 03.5N85W TO 06N90W...THEN TRANSITIONS TO ITCZ...CONTINUING ON TO 06N100W TO 11N117W...WHERE IT BREAKS...THEN RESUMES FROM 09.5N121W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED FROM 02.5N TO 08.5N BETWEEN 80W AND 86W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 150 NM N OF ITCZ BETWEEN 103W AND 113W. SCATTERED TO NUMEROUS MODERATE ISOLATED STRONG CONVECTION NOTED FROM 11N TO 16N BETWEEN 114W AND 117.5W. ...DISCUSSION... THE SUBTROPICAL RIDGE EXTENDS FROM A 1025 MB HIGH NEAR 32N128W SE TO 24N113W AND ALSO SW FROM THE HIGH TO NEAR 26N140W. THE PRES GRADIENT BETWEEN THE LOW CENTER ABOVE AND THE RIDGE IS PRODUCING A BROAD ZONE OF FRESH NE TO E TRADEWINDS S OF 24N EXTENDING W OF 120W TO 140W...WITH ASSOCIATED WIND WAVES MERGING WITH FADING NW SWELL TO PRODUCE SEAS OF 8-10 FT ACROSS THIS AREA. THIS WAVE FIELD WILL DECAY SLIGHTLY AND BECOME CONFINED TO THE WATERS W OF 125W BY SUN MORNING. GULF OF PAPAGAYO...SHARP AND STRONG RIDGING ACROSS CENTRAL AMERICA IS SUPPORTING FRESH TO STRONG NE-E WINDS IN AND DOWNWIND OF PAPAGAYO. WINDS WILL CONTINUE TO PULSE TO 20-25 KT DURING THE NIGHT AND EARLY MORNING HOURS THROUGH 48 HOURS...BRIEFLY INCREASING TO 30 KT DURING THE PERIOD OF MAXIMUM NOCTURNAL DRAINAGE FLOW JUST BEFORE SUNRISE...WITH A BRIEF LULL OF WINDS DIMINISHING TO 20 KT OR LESS DURING THE AFTERNOON HOURS. SEAS WILL BUILD DURING THESE PERIODS OF INCREASING WINDS...REACHING 8- 9 FT DOWNWIND OF THE GULF EACH MORNING. GULF OF PANAMA...FRESH TO LOCALLY STRONG NORTHERLY WINDS ARE PRESENT IN THE WESTERN GULF OF PANAMA PENINSULA DUE TO THE PRESSURE GRADIENT ACROSS THE AREA. WINDS WILL INCREASE THIS EVENING INTO SAT AFTERNOON BEFORE DIMINISHING AGAIN. SEAS OF 4-6 FT WILL BUILD TO 5-8 FT TONIGHT THROUGH SAT. $$ STRIPLING