000 AXPZ20 KNHC 200325 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Nov 20 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...TROPICAL WAVES... The axis of a tropical wave is along 91W N of 04N, moving W at 10 kt. A low to middle level cloud swirl remains evident in satellite imagery along about 07N in the vicinity of the wave. Small clusters of moderate convection are noted behind the wave within 90 nm of the monsoon trough between 83W and 92W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from FROM 09.5N75W TO 09.5N90W TO 09N99W TO 11.5N110W TO 11N120W. ITCZ AXIS EXTENDS FROM 11N120W TO 11N130W TO 11.5N135W TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 90 NM S OF TROUGH BETWEEN 83W AND 101W. SCATTERED MODERATE TO STRONG FROM 08N TO 15N BETWEEN 102W TO 112W, AND FROM 06.5N TO 11.5N BETWEEN 128W TO 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Southerly winds have begun to increase across the northern Gulf of California this evening, with coastal stations showing 10 to 17 kt. Winds are expected to back to the SW and increase to near gale force N of 30N tonight, ahead of a cold front approaching the area from the northwest. Seas will quickly build to 8-10 ft across this area by around sunrise. Additionally, SW gap winds are forecast to accelerate through the prominent low ridges in the mountainous terrain of Baja California Norte as well as central section, which will produce very gusty conditions downstream across the Gulf. Associated deepening low pressure across the desert SW of the U.S. will linger N of the area through Thu and help to maintain strong to near gale force SW across the northern Gulf of California through Wed night before diminishing quickly Thu afternoon. A cold front just NW of the area will sink southward of 30N tonight and into the outer offshore waters late tonight, and reach along 27N to the W of 120W by Wed night. This system will usher in new long period NW swell into the offshore waters west of the Baja California Norte, with building seas in the 8 to 12 ft range on Wed. This swell will spread southward, with seas 8 ft or greater spreading as far south as 22N by Thu evening before subsiding. Low level moisture ahead of the cold front and entrained in the SW winds forecast across Baja California and the Gulf tonight through Wed will spread across north portions of the Gulf and along the western slopes of the Sierra Madre Occidentales, leading to active convection late this evening through Wed morning, and then again Wed afternoon and evening. Moderate high pressure across the Gulf of Mexico will continue to support moderate to strong northerly gap winds across the Gulf of Tehuantepec through Wed afternoon before winds across the Bay of Campeche and the western Gulf of Mexico veer southerly and shut down the northerly flow across Tehuantepec. Light to gentle breezes and slight seas will then persist through the remainder of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE-E winds are expected across the Gulf of Papagayo Wed through Thu with seas building to around 7 ft. Elsewhere, gentle to moderate southwest monsoonal flow will continue across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador for the next several days. REMAINDER OF THE AREA... The remnant low of Tropical Depression Twenty-One-E is near 12.5N109W. Scattered moderate isolated strong convection has recently developed within 180 nm across the NW and 300 nm across the SE semicircles. These remnants are forecast to gradually merge with broad and weak low pressure just to the west of that area, and gradually shift W across the tropics for the next few days. Easterly winds to around 20 kt could persist across the N semicircle of this broad low pressure during this time. Elsewhere a ridge dominates the north waters mainly N of 16N W of 122W. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ is supporting moderate to locally fresh winds north of the ITCZ and west of 125W. Additional pulses of long period NW swell will continue to impact the west-central waters tonight through Thu with seas of 7 to 9 ft from 10N to 15N W of 135W. A new pulse of large, long period NW swell is forecast to reach the forecast waters north of 20N west of 130W Thu night, with seas peaking 12 or 13 ft by Fri. $$ Stripling