000 AXPZ20 KNHC 070325 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sat Mar 07 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 0000 UTC surface analysis and satellite imagery through 0315 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: The very tight tight pressure gradient between strong high pressure ridging southward across eastern and central Mexico and relatively lower pressure south of Mexico has now allowed for the strong gale force north to northeast winds to reach storm strength as they surge southward over the Gulf of Tehuantepec. Last visible satellite imagery reveals low-level cloud streamers shooting off to the southwest and west on both the east and west ends of the Gulf, with clear skies in between indicative of subsidence suppressing moisture within the zone of these ongoing winds. These winds are forecast to continue into Sat morning at those speeds. The culprit high pressure is forecast to slowly weaken as it slides eastward through Mon allowing for these diminish back to strong gale force on Sat and continuing at strong gale force on Sun before diminishing to minimal gale force early on Mon. Peak wave heights will reach about 21 ft tonight into Sat, then gradually subside into early Mon. The wave heights generated by this ongoing storm force wind event will combine with those originating from the Papagayo region, and propagate far downstream from the individual source regions. Please read 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N78W to 04N86W to 04N95W, where scatterometer data indicates it transitions to an ITCZ, which then continues to 05N110W and to 09N125W, where it is bisected by a trough that stretches from 13N126W to 08N128W and to 06N131W. The ITCZ resumes at 06N131W and to beyond the area at 04N140W. Scattered moderate convection is within 180 nm north of the ITCZ between 131W and 135W, and also within 30 nm of the ITCZ between 85W and 88W. Scattered moderate convection is within either side of trough that bisects the ITCZ from 06N to 09N, and also within 120 nm east of trough from 11N to 13N. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section above for details on an ongoing Gulf of Tehunatepec storm wind event. A weak pressure pattern is supporting light to moderate winds across Mexico offshore waters, with the notable exception of a Gulf of Tehuantepec gale wind event. Strong southwest winds will affect the Gulf of California north of 30N Sat night and Sun as a weakening cold front moves onshore. Large long-period northwest swell should impact the waters west of Baja California from Sun through at least Tue night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A north to south pressure gradient across Central America is resulting in strong northeast winds across and offshore the Papagayo region. These winds are expected to reach near gale force Sun night into Mon, with some potential for them to acquire gale force speeds. Wave heights with these winds are expected to be in the range of 8-11 ft. Gulf of Panama: The same pressure pattern affecting the Gulf of Papagayo region will also force fresh to strong north to northeast winds over the Gulf of Panama for the next several days. Wave heights with these winds are expected to reach about 9 or 10 ft. The present Gulf of Tehuantepec gap wind event will bring large west to northwest swell to propagate through the waters west of Guatemala and El Salvador for the next several days. REMAINDER OF THE AREA... A ridge of high pressure extends from a 1021 mb high centered at 29N156W southeastward to near 15N104W. The rather weak equatorward pressure gradient is presently allowing for only gentle to moderate northeast trades north of the ITCZ. Long- period north swell combined with weak wind waves are producing seas 8 to 10 ft between 07N and 11N west of 125W. Large swell propagating downstream from gap winds over the Gulfs of Tehuantepec and Papagayo will expand and merge, to encompass most of the waters south of 13N between 90W and 110W by late Sun. A weakening cold front over the far northwest corner of the area is followed by strong north to northeast winds and waveheights of 8-10 ft. This front will weaken to a trough on Sat and moves westward north of 25N and dissipate late Sat. A stronger cold front will also reach the northwest corner of the area on Sun with both strong southwest winds and strong to near gale force northwest winds behind the front. A rather large extra-tropical low associated to the front is expected to drop southeastward from well north of the area on Sun night and reach to near 31N130W by early Mon. Strong winds along with wave heights expected to build to the range of 12-18 ft could impact the waters north of about 24N and west of 130W on Mon as the attendant cold front pushes well southeastward over the central waters. There is some potential for the winds behind the front to reach gale force late Sun into Mon. Please keep abreast on the latest high seas forecast that will provide wind and wave height details with regards to this system. $$ Aguirre