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Tropical Center

Tropical Weather Discussion...corrected


Issued Active alert

Start Time

Wed 01/16/2019 05:05 PM EST

End Time

Wed 01/30/2019 05:05 PM EST



Full Alert Message

Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 2205 UTC Wed Jan 16 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 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from low pres over central Colombia to the coast at 04N77W and continues to 03N82W, where latest scatterometer data indicates the ITCZ begins. The ITCZ continues to 02N100W and northwestward to 06N107W, where it is briefly interrupted by low near 06N109W. The ITCZ resumes at 06N112W to 06N121W to 07N130W and to beyond the area at 06N140W. Scattered moderate convection is within 120 nm north of the ITCZ between 100W and 107W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: The pressure gradient is gradually relaxing over southeastern Mexico. North to northeast winds funneling out from the Chivela pass and out across the Gulf have diminished to strong to near gale force, with seas up to 12 ft reaching southward from the Gulf to near 13N. Winds will diminish to fresh speeds by early Fri evening and become light and variable on Sat. In the long term, the global models depict that a powerful cold front will move across the western Gulf of Mexico, across southern Mexico and over the Gulf of Tehuantepec by Sat night. Strong high pressure will ridge southward over the western Gulf of Mexico and eastern Mexico. The resultant tight pressure gradient is expected to bring a surge of northerly storm force winds across the Gulf of Tehuantepec as well as downstream from the Gulf beginning on Sun. Very large seas reaching the lower 20s in values are expected with these winds. This upcoming significant event will most probably be similar to a recent significant one that occurred in December. The model guidance suggests that the storm force winds will continue through Sun night, before diminish slightly to strong gale force through Mon. Marine interests transiting through the Gulf of Tehuantepec Sun into early next week should be aware of this upcoming gap wind event, and take necessary action to avoid hazardous marine conditions over the affected waters. Light to gentle breezes prevail off Baja California and across the Gulf of California. Moderate north winds persist off Cabo Corrientes, and light breezes elsewhere off the Mexican coast outside of Tehuantepec. Northwest swell producing seas of 8-10 ft are present in the offshore waters of Baja California and the Revillagigedo Islands. Little change is expected until late Thu with the arrival of a weakening cold front into northern Baja California Norte. While the front will dissipate as it moves across Baja California and the Gulf of California through Fri, it will be accompanied by a new round of long-period northwest swell composed of 12-17 ft seas across the waters off Baja California. This swell will start to impact the waters off Baja California Norte starting Thu night, bringing dangerous surf and large breaking waves across Baja California Norte through Fri. Over the Gulf of California, high pressure building over the Great Basin north of the area will support fresh to strong NW winds extending the length of the Gulf from Fri night through Sat. The strength, fetch and duration of the winds will support wave heights to 8 ft in the southern Gulf of California by Sat night. Winds and seas will diminish by Sun as the high pressure weakens and shifts east. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between high pressure north of the area and the equatorial trough will maintain strong gap winds across Papagayo and Panama through early Sat. Over Papagayo, fresh to strong gap winds persist as far as 300 nm to the W-SW of the Gulf, with winds pulsing to near-gale force during the overnight and early morning hours. Seas will build to 8 to 10 ft. Winds will diminish to 20 kt or less Sat and much of Sun before once again strengthening on Sun night. Over Panama, fresh to strong northerly gap winds will impact mainly the western Gulf of Panama extending into the waters south of the Azuero peninsula through the end of the week. Winds will diminish Sat, and once again strengthen Sun night. REMAINDER OF THE AREA... A cold front has moved over the northwest part of the area, and as of 18Z it extends from near 32N134W to 28N140W. The front marks the leading edge of a rather extensive set of long period, northwest swell that is producing seas in the 12 to 19 ft range. As the front continues eastward tonight, the swell train will propagate through the rest of the northwest and north-central waters, with seas building to 19 to 23 ft north of 27N between 131W and 135W. The front is forecast to reach from near 32N127W to 28N132W by early Thu afternoon as it weakens and dissipate from northern Baja California to 28N122W by early Fri. The northwest swell is forecast to propagate through the remainder of the northwest section of the area through Fri, while it gradually loses energy allowing for the resultant maximum seas to lower to around 15 ft by then. Elsewhere, seas of 8 ft and higher will exist over much of the forecast waters west of 95W. Low pressure of 1009 mb is centered near 06N109W. Fresh to strong winds are noted within 180 nm north and northeast of the low pressure, with seas of 10-12 ft. Latest satellite imagery shows scattered moderate isolated strong convection within 150 nm of the low in the northeast quadrant and within 90 nm of the low in the southeast quadrant. A ridge will build cross the waters north of 25N in the wake of the front. This will support a broad area of fresh to strong trade winds developing over the tradewind belt north of the ITCZ by Fri along with seas of 9-12 ft.