Tropical Weather Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
066 AXPZ20 KNHC 190318 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Sep 19 2024 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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... A western Caribbean tropical wave is along 82W-83W, extending southward across the Costa Rica/Panamanian border to the eastern Pacific waters north of 05N. It is moving westward at 10 kt. Scattered moderate to strong convection described below covers the Pacific waters N of 05N and E of 83W. A tropical wave is along 97W-98W, extending from southeastern Mexico southward over the eastern Pacific waters to near 04N, moving westward at about 10 kt. Scattered moderate to strong convection described below is N of 07.5N to coastal Mexico between 93W and 101W. A tropical wave is along 114W from from 05N to 19N, moving westward at 10 kt. Scattered moderate isolated strong convection described below is from 07.5N to 15.5N between 111W and 118W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11.5N72W to 09.5N82W to 11N88W to 11N116W to 09N128W to 10N140W. Scattered moderate to strong convection is noted from 05N to 10N E of 90W, within 90 nm of the coasts from Costa Rica along 85W to Cabo Corrientes along 107W, from 07.5N to 15.5N between 97W and 120W, and from 07.5N to 13.5N between 120W and 140W. Scattered to locally numerous moderate to strong convection is noted from 07.5N to 11N between 90W and 97W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad surface ridge extends southeastward into the region through 30N129W to offshore of Cabo Corrientes near 17N108W. Over the near and offshore waters of the Baja California peninsula, gentle to moderate NW winds prevail, except for fresh winds near the coast between Punta Eugenia and Cabo San Lazaro. South of 20N through the Revillagigedo Islands similar winds gradually become N. Seas are generally 4 to 5 ft in moderate period swell except 6 ft in the areas of fresh winds. Moderate NW to W winds are across the near shore waters from Cabo Corrientes to Manzanillo. Light to gentle W to SW winds cover the remaining waters eastward to Tehuantepec. Seas south of 20N are to 4 to 5 ft in long period SW swell E of 105W and in NW swell W of 105W. Scattered showers and thunderstorms continue to shift SW off the coast and over the nearshore waters within 75 nm of the Mexican coast between Chiapas and Cabo Corrientes. Light to gentle S to SW winds are over the north and central portions of the Gulf of California while light and variable winds prevail over the southern part of the Gulf. Seas are 1 to 2 ft over the Gulf of California, except 3 to 4 ft in SW swell over the entrance to the Gulf. For the forecast, the current Pacific ridge will remain in place and fluctuate throughout the rest of the week. This pattern will maintain moderate NW to N winds over the offshore waters of Baja California tonight, gradually weakening through Thu afternoon. Expect fresh winds near the coast each evening through Sat. High pressure will strengthen modestly Fri and Sat to bring a return to moderate to fresh winds. Variable winds less than 15 kt are expected across the Gulf of California, except for pulses of moderate W gap winds across southern portions and fresh SW gap winds N of 30N each evening and night through Thu. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate SW to W winds prevail south of the monsoon trough, along about 10N. North of the monsoon trough, moderate or weaker winds are observed. Seas are 4 to 5 ft in SW swell except to 6 ft south through west of the Galapagos Islands. Scattered to locally numerous showers and thunderstorms are within 60 nm of the coasts E of 89W, and offshore from 05N to 09.5N from Colombia westward to beyond 90W. For the forecast, gentle to moderate SW to W winds will continue south of the monsoon trough near 10N, through Thu afternoon, then begin to freshen offshore through Sat. Seas will build to 5 to 7 ft during this time in a mix of SW swell and westerly wind swell. Active weather is expected south of 10N Fri into the weekend. North of 10N, moderate or weaker winds are expected through Thu evening before the monsoon trough begins to lift northward, and winds shift to westerly and gradually increase to gentle to moderate by Sat. Seas will build slightly over the area waters Thu through Sat as a long fetch of westerly winds sets up from offshore to 110W, and generates increasing wind waves moving into the area waters. ...REMAINDER OF THE AREA... Surface ridging extending from a 1029 mb high centered near 41N154W extends east-southeastward to 30N129W to offshore of Cabo Corrientes near 17N108W. The pressure gradient between the ridge and the monsoon trough to the south is forcing moderate NE trades south of about 24N and west of 120W. Seas are 5 to 7 ft in mixed NE and SE swell south of 17N west of 133W, and 4 to 6 ft elsewhere. For the forecast, little overall change is expected over the open Pacific waters for the next several days as the aforementioned ridge dominates the region. A weak cold front that is presently crossing 33N130W will sink southward across 30N east of 130W tonight into early Thu, then push southeastward before dissipating by Fri morning. This will induce a slight decrease in winds during that time period, with winds then increasing slightly Fri through Sun. SW to W monsoonal winds are expected to become well established south of 10N and east of 120W starting Thu through Sun, becoming moderate to fresh. Seas will build to 6 to 8 ft from 03N to 11N east of 120W during that time. $$ Stripling