000 AXPZ20 KNHC 121000 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 901 UTC Sun Jan 12 2020 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front has moved across the much of the Gulf of Mexico Sat and tonight, and across the western Bay of Campeche during the the past several hours, allowing northerly winds to spill through the Isthmus of Tehuantepec, and blast gale force winds across the Gulf of Tehuantepec during the past few hours. Recent scatterometer data between 0300 and 0400 UTC showed these gale force winds to 37 kt across Tehuantepec to the north of 15.5N. Winds there are expected to increase to around 40 kt overnight, with seas building to 13 ft downstream by around sunrise. A tight pressure gradient behind the cold front will support gale force northerly winds funneling across the Gulf of Tehuantepec through around midnight Sun night before winds begin to diminish slightly to around 30 kt. Strong winds to near 30 kt are then expected to persist across Tehuantepec late Sun night through Mon night before increasing again to minimal gale force briefly from around midnight Mon night to Tue morning. Then, strong to near gale force northerly winds are forecast to persist across the Tehuantepec region most of the forecast period, with gale conditions possible again by Thu night. 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 further details on this gale warning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from near 10N75W to 05N79W to 06.5N86W to 04.5N93W. The ITCZ continues from 04.5N93W to 06.5N132W to beyond 05.5N140W. Scattered moderate isolated strong convection is noted from 05.5N to 10N between 127W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad surface ridge extends SE across the offshore forecast waters W of Baja California to SE of the Revillagigedo Islands near 16N106W. The pressure gradient between this ridge and a trough over the Gulf of California will support moderate to fresh northerly winds W of Baja California through the forecast period. New NW swell will propagate through the waters off Baja California Norte today and raise wave heights off of Baja California Norte presently from 5-8 ft, to 8-13 ft by late Sun afternoon, then subside very slowly through Tue. This swell will spread southward, with seas greater than 8 ft prevailing W of the entire Baja California peninsula by Tue. The pressure gradient is also supporting fresh to strong northerly winds across the southern Gulf of California, and also across the waters between Cabo Corrientes and Los Cabos. These winds have begun to diminish tonight and will become moderate to fresh by late Sun morning. Seas across the southern Gulf of California and waters just south of Cabo San Lucas are in the 5-8 ft range, and will gradually subside through tonight as winds diminish. Elsewhere, variable winds at 10 kt or less generally prevail across the near and offshore waters from Manzanillo to Puerto Angel, where seas are running 4-6 ft in NW swell. Northerly winds will gradually increase to around 15 kt across the Manzanillo area by Mon morning, but otherwise, little significant change is expected in marine conditions across the area for the next few days. Gale force winds have begun to spread southward across the Gulf of Tehuantepec tonight. Please see above for more informations on this gale force gap wind event in the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Strong to near gale force winds will continue to blow across and well offshore of the Papagayo region for the next few days, as a strong wind flow in the SW Caribbean blows across Central America and funnels through the various mountain gaps. Winds will peak just below gale force during the overnight and early morning hours. Seas will build to 8-10 ft and possibly to 11 ft well offshore each late night following the pulses of peak winds. This pattern will continue through Wed and also support strong offshore gap winds across the waters of northern Nicaragua and downwind of Lake Managua, as well as the Gulf of Fonseca. Swell generated in the gap wind areas from Tehuantepec and Papagayo will propagate into the Guatemala and El Salvador offshore waters over the next several days to build seas to 6-8 ft. REMAINDER OF THE AREA... A surface ridge extends across the northern forecast waters extends from a 1040 mb high pressure located near 40N150W. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ to the south of the ridge is producing a large area of fresh to strong trade winds that roughly covers the waters N of the ITCZ to about 28N W of 118W. Seas are running in the 9 to 12 ft range within this area of winds. These marine conditions are forecast to persist through the remainder of the weekend as the strong high pressure prevails NW of the forecast region. The aerial extent and strength of the trades will begin to decrease Mon through Wed. New long-period NW swell currently reaching the NE waters will spread SE across the forecast area through early next week. Seas are forecast to peak at 14 or 15 ft roughly N of 27N between 118W and 130W by Sun evening. $$ Stripling