000 AXPZ20 KNHC 152208 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...STRONG NORTHERLY FLOW BETWEEN A FRONTAL BOUNDARY STALLED ACROSS THE E CENTRAL BAY OF CAMPECHE AND RIDGING ALONG THE NE MEXICAN COAST CONTINUES TO FUNNEL THROUGH THE ISTHMUS OF TEHUANTEPEC AND ACROSS THE GULF OF TEHUANTEPEC. WINDS ACROSS TEHUANTEPEC HAVE DIMINISHED BELOW GALE FORCE IN THE PAST SEVERAL HOURS AS WINDS ACROSS 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 OVERNIGHT THROUGH FRI EVENING...THEN MINIMAL GALE FORCE WINDS PERSISTING FRI NIGHT THROUGH SUNRISE SAT...THEN DIMINISHING FOR ABOUT 18-24 HOURS BEFORE THE NEXT ROUND OF GALE FORCE WINDS START SUN EVENING. LATEST WAVE MODEL GUIDANCE INDICATES SEAS OF 10-15 FT BY FRI MORNING DURING THE STRONGEST WINDS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO 06N79W TO 08N84W TO 07N90W...THEN ITCZ AXIS FROM 07N90W TO 07N108W...THEN CONTINUES FROM 08N112W TO 07N140W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 60 NM N AND 180 NM S OF TROUGH BETWEEN 86W AND 92W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 500 NM E OF TROUGH FROM 10N120W TO 18N121W. ...DISCUSSION... THE SUBTROPICAL RIDGE EXTENDS FROM 1026 MB HIGH PRESSURE JUST N OF THE AREA NEAR 34N125W THROUGH 29N122W TO 19N107W. A SERIES OF SURFACE TROUGHS LIE N OF THE ITCZ ALONG 120-121W...132-133W AND 137-138W. THESE TROUGHS ARE ALL ASSOCIATED WITH MID-LEVEL ENERGY FOUND WITHIN A BROAD TROUGH CENTERED ALONG 124-125W. THIS TROUGH IS EXPECTED TO CUT OFF A DEEP LAYER LOW NEAR 13N123W OVER THE NEXT 24-48 HOURS. AN ASSOCIATED SURFACE LOW IS FORECAST TO DEVELOP NEAR 15.5N120W BY FRI MORNING AND MOVE NW THROUGH 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 AND CONVERGING TRADEWINDS TO ITS N WILL ALSO BE A FOCUS FOR DEEP CONVECTION. GULF OF PAPAGAYO...TRADE WINDS IN THE SW CARIBBEAN SEA CONTINUE TO FUNNEL THROUGH THE HIGHER ELEVATIONS OF NORTHERN COSTA RICA INTO THE GULF OF PAPAGAYO. THESE WINDS HAVE DIMINISHED LATE THIS MORNING AND AFTERNOON TO 15-20 KT...BUT ANOTHER ROUND OF FRESH TO STRONG NE-E WINDS IS EXPECTED TONIGHT INTO EARLY FRI...AND AGAIN FRI NIGHT INTO EARLY SAT DURING THE PERIOD OF MAXIMUM NOCTURNAL DRAINAGE FLOW. WINDS WITHIN 90 NM OF THE COAST ARE EXPECTED TO PEAK AT 25-30 KT EACH NIGHT...WITH SEAS BUILDING UP TO 8-9 FT. 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...AND WILL INCREASE TO 20-25 KT N OF 06N TONIGHT AND AGAIN FRI NIGHT. SEAS OF 4-6 FT WILL INCREASE TO 6-8 FT DURING THE PERIODS OF 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 LATE THIS AFTERNOON AND EVENING...DIMINISHING LATE FRI MORNING AS THE PRESSURE GRADIENT WEAKENS. $$ STRIPLING