000 AXPZ20 KNHC 122222 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Feb 12 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 2130 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front moving southeastward across the NW Gulf of Mexico this afternoon is moving south of 20N late this afternoon and will reach the Bay of Campeche by early this evening. Strong high pressure will build southward over eastern Mexico in the wake of this front, with the resulting tight pressure gradient over southeastern Mexico leading to a surge of northerly winds that will funnel through the Chivela pass and out across the Gulf of Tehuantepec. This will induce the next gap wind event across the Tehuantepec region. Gale conditions are expected to begin tonight, and reach to 40 kt by early Wed morning, then continue through Wed night before diminishing below gale force, as high pressure over the Gulf of Mexico weakens as it shifts eastward. 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 is supporting strong to gale force southerly winds over much of the forecast waters N of 20N and W of 127W. The remnants of the low pressure are moving NE across the far NW corner of the discussion area this afternoon, with northerly gales occurring to the NW of the low pressure to move into that area this evening and tonight. As this complex system shifts NE over the next 36-48 hours, gale force southerly winds will shift slowly eastward through this evening 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 06N77W and to 05N87W. The ITCZ begins from 05N90W TO 02.5N103W TO 06N130W TO 08.5N140W. Scattered moderate convection is noted within 30 nm either side of the ITCZ between 93W and 98W and within 210 nm N of the ITCZ between 129W and 138W. ...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 afternoon across much of the Gulf south of the Tiburon Basin, and will gradually diminish 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 bringing gentle to moderate NE to E winds across the offshore waters of Baja California, with seas of 6 to 8 ft in northwest swell. Winds will diminish to light and variable this evening and tonight 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 early Wed. These gap winds will strengthen to 20-25 kt from 10N to 11N between 86W and 88W by late Wed night and continue through early Thu afternoon. 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 108W, with another area of 8 to 9 ft seas covering much of the waters S of 12N between 100W and 115W today 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 18N 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 28N152W, that supports the complex low pressure system mentioned above under the Special Features section. Areas of rain along with embedded showers are possible underneath these clouds, and are expected to last through the end of the week. $$ Stripling