000 AXPZ20 KNHC 231001 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT JAN 23 2016 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... GULF OF TEHUANTEPEC STORM WARNING...STRONG HIGH PRES IS SURGING SOUTHWARD ALONG THE SIERRA MADRE ORIENTAL MOUNTAINS OF MEXICO IN THE WAKE OF A GULF OF MEXICO COLD FRONT. A COLD AND DENSE AIR MASS ASSOCIATED WITH THE HIGH PRES IS SPILLING SOUTHWARD ACROSS SOUTHEASTERN MEXICO...AND THROUGH THE ISTHMUS OF TEHUANTEPEC TO OUT OVER THE VERY WARM SEA SURFACE TEMPERATURES (NEAR 28.0-29.0 DEG CELSIUS) OF THE GULF AS A VERY TIGHT PRES GRADIENT IS ANALYZED ACROSS THE ISTHMUS OF TEHUANTEPEC. N-NE WINDS OF 40-50 KT HAVE MATERIALIZED ACROSS THE GULF OF TEHUANTEPEC...AND SO A STORM WARNING REMAINS HOISTED. AS THE GRADIENT BEGINS TO LOOSEN UP SOME...THESE WINDS WILL BE FORECASTED TO DIMINISH TO STRONG GALE FORCE BY EARLY THIS AFTERNOON...TO MINIMAL GALE FORCE TONIGHT...AND TO BELOW GALE FORCE BY EARLY SUN AFTERNOON. AN ALTIMETER SATELLITE PASS FROM LAST NIGHT REVEALED A MAXIMUM SEA HEIGHT OF 18 FT JUST DOWNSTREAM OF THE GULF. SEAS IN THE RANGE OF 14-20 FT ARE FORECAST WITHIN 45 NM OF A LINE FROM 16N95W TO 14N96W THROUGH EARLY THIS EVENING. SEAS ARE FORECAST TO SLOWLY SUBSIDE TO AROUND 15 OR 16 FT BY TONIGHT...TO 8-10 FT SUN AFTERNOON FURTHER TO LESS THAN 8 FT BY MON AS WINDS QUICKLY DROP OFF TO 10-15 KT BY THAT TIME. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... ITCZ AXIS EXTENDS FROM 04N86W TO 05N100W TO 05N112W TO 05N123W...THEN RESUMES AT 02N130W TO 01N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM N OF AXIS BETWEEN 113W-119W...AND BETWEEN 135W-139W. SIMILAR CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 98W-107W...WITHIN 120 NM N OF THE AXIS BETWEEN 120W-123W...AND WITHIN 60 NM OF THE AXIS BETWEEN 110W-113W. ...DISCUSSION... A DISSIPATING COLD FRONT EXTENDS FROM 32N124W SW TO 26N130W TO 21N140W. THE FRONT SEPARATES TWO HIGH CENTERS...ONE OF 1024 MB AT 31N138W...THE OTHER OF 1021 MB NEAR THE FRONT AT 24N127.5W. ASSOCIATED HIGH PRES RIDGING IS PRESENT N OF 18N W OF 122W. A POST-FRONT TROUGH EXTENDS FROM 32N128W TO 27N137W. THE FRONT IS FORECAST TO SLOW DOWN ITS FORWARD MOTION AND DISSIPATE BY THIS EVENING. LARGE LONG PERIOD NW SWELL GENERATED BY THIS FRONT IS SWEEPING S-SE ACROSS THE NW PORTION OF THE DISCUSSION AREA. RESULTANT SEAS ARE IN THE 8-12 FT RANGE W OF A LINE FROM 32N115W TO 21N140W WITH THE EXCEPTION OF HIGHER SEAS IN THE RANGE OF 10-13 FT N OF 28N BETWEEN 128W-136W. THE SWELL WILL DISPERSE TO THE FAR EASTERN AND SOUTHERN PORTIONS OF THE AREA BY LATE SUN WHILE DIMINISHING IN COVERAGE WITH SEAS IN THE EXPECTED RANGE OF 8-10 FT BY THEN. THE 1024 MB HIGH CENTER IS FORECAST TO INTENSIFY SOME AS IT MOVES ENE TO NEAR 32N130W BY LATE TONIGHT...WHILE THE 1021 MB HIGH IS FORECAST TO DISSIPATE. A TIGHTENING GRADIENT BETWEEN THE 1024 MB HIGH AND LOWER PRES OVER THE SW U.S. SHOULD LEAD TO NW WINDS INCREASING TO THE STRONG RANGE JUST NE OF THE AREA TONIGHT INTO SUN MORNING. SEAS UP TO 12 FT IN NW SWELL WILL ARRIVE TO NEAR 31N118W BY EARLY ON SUN BEFORE SUBSIDING TO 8-10 FT SUN AFTERNOON. A SURFACE TROUGH IS ANALYZED AT 06Z ALONG A POSITION FROM 07N124W TO 02N129W. SATELLITE IMAGERY SHOWS SCATTERED MODERATE/ ISOLATED STRONG CONVECTION BETWEEN THE TROUGH AND 123W FROM 05N TO 07N. THE TROUGH IS FORECAST TO SHIFT WESTWARD THROUGH SUN NIGHT WHILE REMAINING WEAK. UPPER LEVEL TROUGHING IS FORECAST BY THE NWP MODELS TO QUICKLY PASS OVER THE CENTRAL PORTION OF THE AREA SUN AND MON...AND GENERATE A SURFACE TROUGH NEAR 111W BY SUN NIGHT. THIS TROUGH WILL ALSO GRADUALLY SHIFT WESTWARD THROUGH MON WITH ONLY SOME INCREASE IN THE TRADES TO ITS NW AND N POSSIBLE AS THE AFOREMENTIONED HIGH PRES TO THE N INTENSIFIES SOME. GAP WINDS... GULF OF PAPAGAYO...A STRONG PRES GRADIENT BETWEEN BUILDING HIGH PRES OVER THE YUCATAN PENINSULA AND NORTHERN CENTRAL AMERICA WITH LOWER PRES PRESENT S OF 11N WILL MAINTAIN FRESH NE WINDS THROUGH THE GULF INTO EARLY NEXT WEEK. THESE WINDS WILL INCREASE TO THE STRONG RANGE IN THE GULF TONIGHT...AND INTO EARLY ON SUN BEFORE WEAKENING SOME SUN AFTERNOON. GFS GUIDANCE SUGGESTS THAT THESE WINDS WILL REACH STRONG TO NEAR GALE FORCE INTENSITY LATE SUN NIGHT INTO EARLY MON MORNING WITH SEAS EXPECTED TO BUILD TO AROUND 10 FT. GULF OF PANAMA...WITH STRONG HIGH PRES FROM THE GULF OF MEXICO BUILDING S INTO THE WESTERN CARIBBEAN AND LOWER PRES PRESENT OVER NW COLOMBIA...THE INDUCED PRES GRADIENT IS EXPECTED TO DEVELOP FRESH TO STRONG NE WINDS ACROSS THE GULF BEGINNING NEAR 12Z THIS MORNING. THESE WINDS WILL SEEP S FROM THE GULF TO NEAR 03N BY SUN MORNING AND CONTINUE INTO MON WITH SEAS 6-8 FT TONIGHT...FORECAST TO BUILD TO 8-10 FT BY SUN EVENING. SEAS OF 8 FT IN NE SWELL ARE FORECAST TO SPREAD S TO NEAR 02N BY LATE SUN NIGHT BETWEEN 80W-83W. $$ AGUIRRE