000 AXPZ20 KNHC 190335 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU FEB 19 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 0300 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...STRONG SURFACE HIGH PRESSURE IS BUILDING ACROSS THE WESTERN GULF INTO SOUTHERN MEXICO BEHIND A COLD FRONT THAT IS CURRENTLY MOVING ACROSS THE YUCATAN PENINSULA AND NORTHERN GUATEMALA. THE TIGHT SURFACE PRESSURE GRADIENT ALONG WITH A PUSH OF DENSE DRY AND COLD AIR THROUGH THE CHIVELA PASS IN SOUTHERN MEXICO IS RESULTING IN GALE FORCE WINDS IN THE GULF OF TEHUANTEPEC. MINATITLAN...ON THE NORTHERN END OF THE ISTHMUS OF TEHUANTEPEC...IS REPORTING SUSTAINED WINDS OF NEAR 30 KT WITH HIGHER GUSTS. WINDS ARE FORECAST TO INCREASE TO 40 KT OVERNIGHT TONIGHT AND EARLY THU WITH THE AID OF THE NOCTURNAL DRAINAGE FLOW. THE SEA HEIGHTS WILL BUILD DOWNSTREAM OF THE GULF OF TEHUANTEPEC...REACHING AS HIGH AS 15 FEET BY EARLY THU MORNING. THE GALE-FORCE WINDS WILL PERSIST THROUGH EARLY FRI MORNING...AND THEN DIMINISH TO 25-30 KT AS THE HIGH PRESSURE TO THE N OF THE AREA WEAKENS AND SHIFTS EASTWARD. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE ITCZ AXIS EXTENDS FROM 06N85W TO 04N95W TO 06N110W TO TO 05N130W TO 06N140W. SCATTERED MODERATE CONVECTION IS NOTED FROM 05N TO 07N BETWEEN 86W AND 88W. SIMILAR CONVECTION IS FROM 05N TO 08N BETWEEN 124W AND 127W...AND FROM 05N TO 08N W OF 134W. ...DISCUSSION... A CUT-OFF MID TO UPPER LOW IS SPINNING NEAR 17N135W WITH A TROUGH EXTENDING SOUTH TO NEAR 05N135W. THE CUT-OFF LOW IS AT THE SOUTHERN END OF A NARROW UPPER TROUGH THAT EXTENDS ACROSS THE NW CORNER OF THE AREA FROM 30N133W TO 17N135W. A SURFACE TROUGH REFLECTION OF THIS UPPER-LEVEL FEATURE IS ANALYZED FROM 18N127W TO 07N136W. A RECENT RAPIDSCAT SHOWS VERY WELL THE WIND SHIFT ASSOCIATED WITH THIS TROUGH. SCATTERED MODERATE CONVECTION IS RELATED TO THIS TROUGH AND COVERS THE WATERS FROM 11N TO 16N BETWEEN 124W AND 127W ON THE EAST SIDE OF THE TROUGH...AND FROM 16N TO 19N BETWEEN 128W AND 131W ON THE WEST SIDE. THE SAME SCATTEROMETER PASS INDICATE GENTLE TO MODERATE WINDS NEAR THE TROUGH AXIS WITH SOME HIGHER WINDS NEAR THE CONVECTIVE ACTIVITY. AN AREA OF SEAS TO 9 FT IS OBSERVED FROM 04N TO 12N BETWEEN 128W AND 134W BASED ON AN ALTIMETER PASS AND MARINE GUIDANCE. THIS IS DUE TO LONG PERIOD SWELL FROM THE NORTHWEST. THIS IS FORECAST TO DECAY TO 8 FT AS IT PROPAGATES SE AND SHRINK IN AREAL EXTENT AFFECTING ONLY THE WATERS FROM 10N TO 13N BETWEEN 125W AND 128W BY 48 HOURS. THE UPPER FEATURES WILL GRADUALLY WEAKEN BUT REMAIN GENERALLY IN PLACE THROUGH THE NEXT 24 TO 48 HOURS. THIS WILL KEEP THE SURFACE TROUGH IN PLACE AS WELL. A 1025 MB HIGH PRES CENTERED NEAR 33N130W EXTENDS A RIDGE SE ACROSS THE FORECAST WATERS TO NEAR 17N110W. A SECOND SURFACE TROUGH...REMNANTS OF AN OLD COLD FRONT...STRETCHES FROM 31N138W TO 22N140W. THIS TROUGH WILL CONTINUE TO MOVE WESTWARD AND DISSIPATE BY LATE THU. AT THE SAME TIME...THE HIGH PRES WILL STRENGTHEN...ALLOWING FOR A SLIGHTLY TIGHTER GRADIENT BETWEEN THE FIRST TROUGH AND THE RIDGE...ENHANCING TRADE WIND FLOW SOMEWHAT FROM 10N TO 20N BETWEEN 120W AN 130W. GAP WINDS...WINDS ARE FORECAST TO INCREASE TO 20-25 KT ACROSS THE GULF OF PAPAGAYO BY THU MORNING AS HIGH PRES BUILDS ACROSS THE NW CARIBBEAN AND NORTHERN CENTRAL AMERICA IN THE WAKE OF A COLD FRONT CURRENTLY MOVING ACROSS THE NW CARIBBEAN. MARINE GUIDANCE SUGGESTS INCREASING WINDS TO 30 KT WITH BUILDING SEAS TO 9 FT ACROSS THE GULF OF PAPAGAYO BY FRI MORNING. MODERATE TO FRESH NORTHERLY WINDS ARE ALSO EXPECTED ACROSS THE GULF OF PANAMA BY FRI MORNING AS WINDS FUNNEL INTO THE GULF FROM THE SW CARIBBEAN. $$ GR