000 AXPZ20 KNHC 292116 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2116 UTC Tue Jan 29 2019 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 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Light and variable winds with seas less than 4 ft prevail across the Tehuantepec region. However, minimal gale force northerly winds are expected to develop across the Gulf of Tehuantepec late this evening through early Wed morning as a new high pressure ridge builds southward along the eastern slopes of the Sierra Madre mountains behind a cold front moving across the western Gulf of Mexico. This will be a short-lived Tehuantepec gap wind event as the the pressure gradient over southeast Mexico weakens once again on Wed. This will allow winds to diminish back to fresh to strong force by Wed morning, and to 20 kt or less by Wed evening. Maximum seas during the gale force winds will build to 10 ft by early Wed morning. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from a 1009 mb low pressure located over northwest Colombia near 08N74W to 04N95W. The ITCZ continues from 04N95W to beyond 08N140W. Scattered moderate convection is from 03N to 05N between 89W and 92W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak ridging extends from 1022 mb high pressure centered near 29N130W through the Revillagigedo Islands. This is maintaining light to gentle breezes across the region. Wave heights are 3 to 5 ft in open waters and 1 to 3 ft in the Gulf of California. The pattern will change by Thu as a vigorous mid/upper level disturbance moves south along the coast of southern California, supporting 1011 mb low pressure and accompanying cold front into the mouth of Colorado River and northern Gulf of California. This will result in fresh to strong S to SW winds across the far northern Gulf of California by Thu night. This will be short- lived however as the disturbance pivots through the region. Looking ahead, a another disturbance moves into California with a slightly stronger cold front moving across Baja California Norte and the northern Gulf of California by late Sat into early Sun. This will bring another pulse of strong S to SW winds to the northern Gulf of California late Sat. The front will also be accompanied by longer period NW swell of 8 to 12 ft reaching Guadalupe Island and the northern portion of Baja California Norte by Sat night. The swell will decay as it moves south, but seas of 8 to 10 ft will cover the waters off Baja California through late Sun. Elsewhere off Mexico, gentle breezes and 4 to 6 ft seas will persist through Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong northeast winds are expected during the overnight and early morning hours most of the forecast period. These winds may reach around 30 kt tonight and each night through Thu night. Gulf of Panama: Expect fresh to strong N to NE winds at night through Thu night. Seas are forecast to reach 6 to 8 ft with these winds Wed through Fri. REMAINDER OF THE AREA... A tight pressure gradient persists between broad deep layered low pressure west of the area and a ridge north of 20N. This pattern is resulting in fresh E to SE winds from 09N to 20N W of 135W. These marine conditions are expected to generally persist on Wed, with seas building to 9 to 12 ft, then diminish Thu as the supporting upper low weakens and lifts northward. A weak cold front is expected to move into the northern waters north of 28N Thu then lift northward. A slightly stronger cold front will follow Thu night, and reach from Baja California Norte to 22N140W by late Sun. Strong winds will accompany the front north of 27N Fri and Sat. High pressure building in the wake of the front will support fresh to strong trade winds from 20N to 25N west of 135W Fri night through Sun. $$ Christensen