Pacific Discussion

  • NHC East Pacific Tropical Weather Discussion
    by (nhcwebmaster) on October 22, 2018 at 9:00 AM

    000 AXPZ20 KNHC 220900 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Oct 22 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 0900 UTC. ...SPECIAL FEATURES... Hurricane Willa centered near 18.2N 107.1W at 22/0900 UTC moving N at 6 kt. Estimated minimum central pressure is 931 mb. Maximum sustained wind speed is 135 kt with gusts to 165 kt. Numerous strong convection is currently observed within 75 nm of the center, surrounded by scattered moderate to strong convection in bands within 300 nm of the center. Some of these rain bands will bring very heavy rainfall along the Pacific coast of mainland Mexico from 103W to 107W through Tue evening as Willa tracks N, and later turns NE across the central Mexican offshore waters. Large swells generated by Willa will continue to reach the mainland Mexican coast between 102W and 108W through Tue night, and are likely to cause life-threatening surf and rip current conditions. Please refer to local forecasts from the Meteorological Service of Mexico for specific information on heavy rainfall and flash flood potential from Willa. Refer to the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 KNHC for additional details. Tropical Storm Vicente centered near 14.1N 99.7W at 22/0900 UTC moving W at 9 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate to strong convection along a band within 180 nm over the W semicircle of the center. Vicente will continue on a general westward track through the southern Mexican offshore waters this morning then turn N and gradually weaken through Tue dissipating by late Wed. Refer to the latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 KNHC for additional details. ...TROPICAL WAVE... A tropical wave is analyzed N of 06N along 90W with scattered moderate isolated strong convection flaring within 60 nm of 07N90.5W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Caribbean coast of Colombia at 10N76W to the Pacific coast of Costa Rica at 09N83W and through a tropical wave at 09N90W then turns NW to 12N95W where it loses identity in the cyclonic circulation associated with Tropical Cyclone Vicente. The monsoon trough resumes SW of Hurricane Willa at 13N112W, and continues SW through an embedded 1008 mb surface low at 11N117W to 09N128W to 11N140W. Scattered moderate isolated strong convection is observed within 120 nm either side of a line from 05N78W to 09N87W, and within 150 nm of 09N94W and 11N110W and 07N132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features paragraph for details on Tropical Cyclones Vicente and Willa. W of the Baja california Peninsula...Gentle to locally moderate NW to N flow is expected through this evening when the pressure gradient will tighten, supporting moderate to locally fresh northerly flow W of the Baja California Peninsula on Tue into early Wed as Willa passes to the S. Large southerly swell from Tropical Cyclone Willa will propagate N through the waters W of Baja beginning this evening, and reaching as far N as 26N early Wed, before beginning to subside from the N. Gulf of California: Light, mostly northerly flow is expected through this afternoon when large southerly swell from Tropical Cyclone Willa will propagate into the southern gulf waters, and then persist through late Tue night. Fresh to locally strong northerly winds are also expected across the gulf waters S of 24.5N on Tue night into Wed as Willa passes S of the gulf entrance. Gulf of Tehuantepec...Fresh to locally strong northerly flow is expected through late this morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Pulses of fresh NE flow are forecast through this morning. Light northerly winds and 4 to 7 ft seas are forecast elsewhere N of the monsoon trough, while moderate to locally fresh southwesterly monsoonal flow, with 5 to 8 ft seas forecast through this afternoon, then mostly moderate SW flow and 4 to 6 ft seas are forecast through the middle of the week. REMAINDER OF THE AREA... Refer to the Special Features paragraph above for details on Tropical Cyclone Willa. A 1008 mb low near 11N117W will drift W for the next several days with fresh southerly flow, and 6 to 8 ft seas forecast within 300 nm SE of the low. This low has a low chance of becoming a tropical cyclone during the 5 days. A surface high will meander near 27N136W with moderate to locally fresh anticyclonic flow forecast across the tropical waters N of the monsoon trough and ITCZ, and W of 122W through the middle of the week. An area of 7 to 9 ft seas is observed across the tropical waters from 12N to 22N W of 134W. These conditions will shift W of the area tonight. $$ Nelson […]