000 AXPZ20 KNHC 091442 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1442 UTC Mon Jan 9 2017 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 1430 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong high pressure over eastern Mexico combined with low pressure to the south of the area near the monsoon trough continues to support strong gale force winds offshore across the Gulf of Tehuantepec. Seas are up to around 20 ft at this time. A large area of NE swell generated by this gap wind event will propagate far from its source region west to 120W, and south of the equator over the next couple of days. The pressure gradient will gradually loosen through Tuesday night with gale force winds diminishing by early Wednesday. Nocturnal northerly flow will then pulse to fresh to strong thereafter. Gulf of Papagayo Gale Warning: A tight pressure gradient between high pressure centered north of the area and low pressure within the monsoon trough has increased winds funneling into the Gulf of Papagayo. These gradient winds, with the added component of nocturnal drainage flow, has helped winds reach minimal gale force over the Gulf of Papagayo. Winds may diminish briefly below gale force early this evening, but are once again expected to ramp up to gale force late tonight into early Tuesday. Winds are then expected to diminish below gale force Tuesday afternoon. Seas are up to 11 to 13 ft downwind of the gulf. Gap winds will pulse to near gale force Tuesday night, and then fresh to strong thereafter, with the strongest winds expected during the overnight and early morning hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 07N76W to low pressure near 05N79W to low pressure near 04N102W. The intertropical convergence zone axis extends from 04N102W to 08N120W to low pressure near 07N137W to 07N140W. Scattered moderate and isolated strong convection is within 120 nm of the low near 05N79W, and also from 07N to 12N between 127W and 137W. Scattered moderate convection is from 06N to 08N between 110W and 112W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for more details on the Gulf of Tehuantepec gale force gap wind event. A weak pressure gradient prevails over much of the remaining forecast region. Light to gentle winds with 3 to 5 ft seas prevail off the coast of the Baja California peninsula and along the southwest coast of Mexico. Northwest swell will propagate into the waters offshore of Baja California Norte Wednesday night, building seas 7 to 10 ft by early Thursday morning through the end of the week. The pressure gradient across northwest Mexico will increase Tuesday night with winds within 60 nm of the Pacific coast of the peninsula increasing to moderate to fresh through the end of the week. Northwest flow in the far northern Gulf of California will increase to fresh to strong Friday as the gradient also tightens there. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the special features section for more details on the Gulf of Papagayo gale force gap wind event. The tight pressure gradient responsible for the Gulf of Papagayo gale force winds will support fresh to strong northeast winds southwest of Nicaragua, including the Gulf of Fonseca, through mid-week. In the Gulf of Panama and near the Azuero Peninsula, northerly winds have increased to 20 to 25 kt as strong winds have started to funnel into the area from the southwest Caribbean. Winds are expected to remain fresh to strong through mid-week before diminishing. Seas will build to 8 to 10 ft south of the peninsula by early Tuesday. The combined swell generated from the Gulf of Papagayo and Gulf of Tehuantepec gap wind events will generate a large area of 8 ft or greater seas that will extend from the Tehuantepec and Papagayo regions southward to near the equator and westward to near 120W by late Tuesday. REMAINDER OF THE AREA... A large occluded low pressure system north of the area extends a cold front through 30N124W to 18N140W. Weak high pressure is centered east of the cold front near 26N123W, while high pressure at 1022 mb has built in the wake of the cold front, centered near 27N140W. The height rises behind the front have helped loosen the pressure gradient over the northern waters and winds have diminished to gentle to moderate. The low pressure area well north of the area will continue to generate pulses of moderate to large northwest swell which will propagate into the northwest waters, with seas building above 8 ft over the northwest waters through the day today. The combination of swell generated from the Gulf of Papagayo and Gulf of Tehuantepec gap wind events has generated an east to northeasterly swell that is propagating from the area. This swell, with seas greater than 8 ft, will move across the waters roughly from 05N to 15N through the week. This swell will eventually merge with fresh northeast-east tradewind swell across the west- central waters by the end of the week. $$ LEWITSKY