000 AXPZ20 KNHC 110849 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 849 UTC Sun Mar 11 2018 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 0830 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Light to moderate onshore winds will prevail through early Mon morning. Strong high pressure ridging will build southward along eastern Mexico and the western Gulf of Mexico behind a strong cold front through the early part of the week. Winds will become northerly and rapidly increase to fresh to strong in the Gulf of Tehuantepec by late Mon morning, continuing to increase to gale force late Mon afternoon, and peaking around 45 kt Mon night into early Tue. Gale force winds will likely diminish by midday Thu, with brief lulls below gale force also possible during the afternoon hours Tue and Wed. Seas will peak around 15 to 17 ft Mon night into Tue morning. Please see the latest Pacific Ocean High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC, for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 06N84W to 04N95W. The ITCZ axis continues from 04N95W to 03N120W to 03N140W. Scattered moderate and isolated strong convection is noted within an area bounded by 10N137W to 07N136W to 05N137W to 06N140W to 10N140W to 10N137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for information on the Gulf of Tehuantepec developing gale warning. Weakening 1016 mb high pressure centered near 28N118W ridges SE across the open waters W of the Baja California peninsula. Mainly light to moderate NW to N winds prevail beneath this ridge. Winds will increase to between 15 and 20 kt later this morning through Tue as the high gradually builds. The high will then dissipate by Wed as a decaying cold front approaches. Winds near Cabo Corrientes could become locally strong through early this afternoon. Long period NW swell will cause seas to build to between 6 and 8 ft W of 110W Wed through Thu. Gulf of California: Light to gentle winds will increase to between 10 and 15 kt across the Gulf S of 28N this afternoon through Tue in response to building high pres just NW of the offshore zones. Winds will become fresh to locally strong over the waters S of 26N tonight. The pressure gradient across the region will weaken Tue night through Thu, which will allow winds to diminish to between gentle and moderate across the Gulf of California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure ridging over the Caribbean from the SW Atlc will be just strong enough to support one more round of fresh to strong winds over the Gulf of Papagayo, through this morning. The ridging will continue to weaken but still produce pulsing moderate to fresh winds tonight through Tue, then increasing back to fresh to strong at night as the pressure gradient restrengthens Tue night through Thu night, peaking near 30 kt early Thu morning. Over the Gulf of Panama, gentle to moderate winds will prevail through Wed, increasing to moderate to fresh thereafter. Seas are expected to be 4 to 6 ft as moderate cross-equatorial SW swell continue to arrive. Elsewhere, expect gentle to moderate winds and 4 to 7 ft seas to prevail. REMAINDER OF THE AREA... A complex pattern remains across the NW portion and N central waters with one cold front extending from 1013 mb low pressure just offshore of San Diego, California near 32N119W to 27.5N127.5W, with a second cold front extending from 1011 mb low pressure near 32N134W to 30N131W to 20N138W. A plume of deep tropical moisture extends from SE of the Hawaiian Islands northeastward over the discussion waters. Scattered moderate convection is present within an area bounded by 30N131W to 30N120W to 25N127W to 24N134W to 20N140W to 23N140W to 30N131W. Associated winds with these features are mainly light to locally moderate, with seas in the 4 to 6 ft range. A stronger cold front will approach 30N140W from the NW by later this morning. An area of fresh to strong winds will precede the front, as well as follow it, finally diminishing by Mon night. Large NW swell will also accompany the boundary, reaching as high as 14 to 16 ft by Mon evening. The front will weaken as it moves across the waters N of 24N and W of 125W. A weaker cold front will introduce a round of reinforcing NW swell Wed night and Thu. Moderate to locally fresh trades combined with decaying NW swell are supporting combined seas of 7 to 8 ft across the waters from 07N to 11N between 130W and 137W. The pressure gradient will weaken on Sun and allow seas to subside to less than 8 ft in this area by Sun afternoon. $$ Lewitsky