000 AXPZ20 KNHC 130336 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Feb 13 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front moving southeastward across the Gulf of Mexico this evening has reached the western Bay of Campeche and southern Mexico. Strong high pressure building southward over eastern Mexico in the wake of this front is producing strong northerly gap winds just beginning to spill across the Gulf of Tehuantepec. Gale force northerly winds are expected to begin within the next few hours, and reach to 40 kt by early Wed morning, then continue through Wed night before diminishing below gale force. Winds will further diminish to 20 kt or less on Thu. Associated seas with this event are expected to peak near 18 or 19 ft by midday Wed. Eastern North Pacific Gale Warning: A broad ridge anchored by strong high over the Great Basin covers the northern forecast waters to the north of 20N and east of about 125W. The very tight pressure gradient between this area of high pressure and the remnants of the strong storm system exiting the Hawaiian Islands region and moving across the far NW portion of the discussion area is supporting strong to gale force southerly winds over much of the forecast waters N of 20N and W of 125W. An associated cold front extends from 30N138W TO 29N140W with northwest gales entering the waters behind it. As this complex system shifts NE over the next 36-48 hours, gale force southerly winds will shift slowly eastward through tonight to near 125W, and then NE and out of the area Wed morning. The associated cold front will produce a brief period of gale force winds on either side of the front overnight. The high pressure ridge will gradually weaken over the next 24 hours, allowing for winds to diminish below gale force by Wed morning. The cold front will usher in a fresh set of long-period northwest swell, with seas peaking near 18 ft late tonight through Wed before they begin to slowly subside. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03/HSFEP2, or at the website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details on both of these gale warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 10N74W TO 05N87W. The ITCZ begins from 05N87W TO 02N109W TO 08N140W. Scattered moderate isolated strong convection is noted within 45 nm either side of the ITCZ between 87W and 101W, and north of the ITCZ and the gale system entering the NW waters from 04N TO 25N between 131W AND 140W and from 19N TO 27N between 127W AND 132W ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the upcoming gale force gap wind event in the Gulf of Tehuantepec. Gulf of California: Fresh NW winds continue this evening across much of the Gulf south of the Tiburon Basin, and will gradually diminish by early Wed as the strong high pressure over the Great Basin weakens. Afternoon altimeter data showed seas of 6-8 ft across southern portions of the Gulf, which will slowly diminish tonight through Wed morning. The pressure gradient associated with high pressure over these waters is producing variable light to moderate winds across the offshore waters of Baja California, with seas of 5 to 7 ft in northwest swell. These Winds will persist overnight as a high pressure center develops offshore of Baja California Sur. Elsewhere, light to gentle breezes and seas in the 4 to 6 ft range will prevail between the Gulf of Tehuantepec and Cabo Corrientes through the forecast period. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh northeast to east winds prevail across the Gulf of Papagayo and reach west to near 88W, with little change in conditions expected through late Wed. These gap winds will strengthen to 20-25 kt late Wed night and continue through Fri. Winds will be greatest during the overnight and early morning hours with the assistance of the nocturnal drainage flow. Gulf of Panama: Gentle to moderate north winds will continue over the Gulf of Panama through the end of the week. Light to gentle breezes will persist elsewhere through Fri. REMAINDER OF THE AREA... Please see above for more on the upcoming gale force winds over portions of the discussion waters N of 22N and W of 125W. Elsewhere, long-period northwest swell continues across the forecast waters, mixing with long-period cross equatorial southwest well. Seas of 8 ft or greater will dominate most of the waters W of 112W, with another area of 8 to 9 ft seas covering much of the waters S of 12N between 108W and 125W tonight before areal coverage of seas greater than 8 ft decreases. Satellite imagery shows ample deep layer moisture in the form of mostly mid and upper-level clouds north of about 20N streaming northeastward in strong southwest mid and upper-level flow. This flow is located ahead of a large cyclonic vortex located west of 140W near 28N153W, that supports the complex low pressure system mentioned above under the Special Features section. Areas of rain along with embedded showers and isolated thunderstorms embedded within these clouds, and are expected to last through the end of the week, and gradually shift into California. $$ Stripling