000 AXPZ20 KNHC 151520 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU JAN 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...NORTHERLY FLOW BETWEEN A FRONTAL BOUNDARY STALLED ALONG 94W OVER THE SW GULF OF MEXICO AND RIDGING ALONG THE NE MEXICAN COAST IS FUNNELING THROUGH THE ISTHMUS OF TEHUANTEPEC. GALE FORCE WINDS HAVE DIMINISHED IN THE PAST FEW HOURS AS WINDS IN THE SW GULF OF MEXICO N OF THE AREA HAVE TEMPORARILY SLACKENED. A NEW AND REINFORCING SURGE OF NORTHERLY FLOW IS EXPECTED TO MOVE INTO THE GULF OF TEHUANTEPEC AROUND SUNSET TODAY WHEN WINDS WILL INCREASE BACK TO GALE FORCE. LATEST MODEL GUIDANCE INDICATES WINDS INCREASING TO 40 KT AROUND DAYBREAK FRI...WITH MINIMAL GALE FORCE WINDS PERSISTING THROUGH SUNRISE SAT...THEN DIMINISHING FOR ABOUT 18-24 HOURS BEFORE THE NEXT ROUND OF GALE FORCE WINDS START SUN EVENING. THE LATEST TAFB-NWPS MODEL GUIDANCE INDICATES SEAS OF 10-14 FT BY FRI MORNING DURING THE STRONGEST WINDS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO 05N92W. THE ITCZ AXIS EXTENDS FROM 05N92W TO 07N110W TO 05N124W TO 07N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 90 NM S OF THE AXIS E OF 80W AND WITHIN 120 NM SE OF THE AXIS BETWEEN 86W AND 92W. ...DISCUSSION... THE SUBTROPICAL RIDGE EXTENDS FROM 1026 MB HIGH PRESSURE JUST N OF THE AREA NEAR 34N125W THROUGH 29N122W TO 19N108W. A TROUGH WHICH IS THE REMNANTS OF AN OLD STATIONARY FRONT LIES JUST W OF THE RIDGE FROM 30N132W TO 22N138W. A SERIES OF SURFACE TROUGHS LIE N OF THE ITCZ ALONG 122W...133W AND 138W. THESE TROUGHS ARE ALL ASSOCIATED WITH MID-LEVEL ENERGY FOUND WITHIN A BROAD TROUGH CENTERED ALONG 124W. THIS TROUGH IS EXPECTED TO CUT OFF A DEEP LAYER LOW OVER THE NEXT 12-24 HOURS. AN ASSOCIATED SURFACE LOW IS FORECAST TO DEVELOP NEAR 15.5N120W BY FRI MORNING AND MOVE NW THROUGH THE END OF THE FORECAST PERIOD SAT MORNING. THE PRES GRADIENT BETWEEN THE LOW AND THE EXPANDING SUBTROPICAL RIDGE SHOULD BE STRONG ENOUGH TO SUPPORT FRESH TO STRONG WINDS ON THE NW SIDE OF THE LOW...POSSIBLY INCREASING TO NEAR GALE FORCE. THIS LOW WILL ALSO BE A FOCUS FOR DEEP CONVECTION. GULF OF PAPAGAYO...TRADE WINDS IN THE SW CARIBBEAN SEA CONTINUE TO FUNNEL THROUGH NORTHERN COSTA RICA INTO THE GULF OF PAPAGAYO. THESE WINDS WILL DIMINISH LATER THIS MORNING WITH ANOTHER ROUND OF FRESH TO STRONG NE-E WINDS EXPECTED TONIGHT INTO EARLY FRI... AND AGAIN FRI NIGHT INTO EARLY SAT DURING THE PERIOD OF MAXIMUM NOCTURNAL DRAINAGE FLOW. SEAS WILL BUILD UP TO 8-9 FT DURING THE STRONGEST WINDS. GULF OF PANAMA...FRESH NORTHERLY WINDS ARE EXPECTED IN THE WESTERN GULF OF PANAMA AND JUST SE-S OF THE AZUERO PENINSULA DUE TO A TIGHT PRESSURE GRADIENT ACROSS THE AREA. SEAS WILL BE UP TO 4-6 FT NEAR THE STRONGEST WINDS. GULF OF CALIFORNIA... A SLOW MOVING POSITIVELY TILTED UPPER TROUGH WILL MOVE EASTWARD THROUGH THE SW UNITED STATES OVER THE NEXT FEW DAYS. AT THE SURFACE...THE PRESSURE GRADIENT WILL BUILD BETWEEN LEE SIDE TROUGHING ALONG THE W SLOPES OF THE SIERRA MADRE OCCIDENTAL AND INCREASED RIDGING OVER THE GREAT BASIN IN THE WAKE OF THE UPPER TROUGH. THE LATEST RAP AND NAM MODEL GUIDANCE INDICATES NW-N WINDS INCREASING TO 20-25 KT IN THE NORTHERN GULF OF CALIFORNIA N OF 29.5N W OF 113.5W THIS EVENING...DIMINISHING FRI MORNING AS THE PRESSURE GRADIENT WEAKENS. $$ LEWITSKY