Tropical Weather Discussion

axpz20 knhc 092152

Tropical weather discussion
NWS National Hurricane Center Miami FL
2021 UTC Mon Dec 9 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
2100 UTC.

...Special features...

The next gale force gap wind event is expected to affect the 
Gulf of Tehuantepec Wed morning through around midday Thu as a 
strong cold front crosses the Gulf of Mexico. Winds over 
Tehuantepec will abruptly increase to gale force during the 
morning and could peak near 45 kt Wed afternoon or evening. 
Strong winds Thu evening will taper to fresh by Fri evening.

...Intertropical convergence zone/monsoon trough...

The monsoon trough extends from low pres 1010 mb near 10n73w to 
06n80w to 07n90w. The ITCZ continues from 07n90w to 07n120w to 
08n130w to 09n135w. Scattered moderate convection is from 06n to
12n between 101w and 140w.

Offshore waters within 250 nm of Mexico...

Light to gentle NW to N winds prevail across most of the 
offshore waters of Baja California this morning. High pressure 
centered NW of the area near 32n129w is building gradually into 
the northern waters, and should cause winds to slowly increase 
across the area. Seas across the baja waters remain 5-8 ft in NW 
swell, except 9 ft across the far outer waters. Seas are expected
to slowly subside through Tue night.

Inside the Gulf of California, satellite-derived wind data 
indicated light and variable winds across most of the basin, 
with seas 3 ft or less. Winds are expected to become NW to N and 
slowly increase through Tue evening. Fresh NW to N flow is then 
expected to prevail across central and southern sections of the 
Gulf through Wed morning with seas building to between 4 and 7 
ft. Winds could be locally strong across the central Gulf Tue 

Elsewhere across the Mexican offshore waters, recent 
scatterometer data showed NW to W winds around 10 kt from Cabo 
Corrientes to Puerto Angel, becoming light and variable well 
offshore. The high pressure building across the baja offshore 
waters tonight will build very weakly across the waters south of 
Cabo Corrientes tonight through Tue and generate generally NW to 
N winds of 10 to 15 kt across most of the remaining Mexican 
waters through Wed.

Offshore waters within 250 nm of Central America, Colombia, and 
within 750 nm of Ecuador... 

Fresh NE to E winds will pulse to strong tonight across and 
downstream of the Gulf of papagayo, then generally remain fresh 
Tue and Wed before increasing again Thu. Seas will peak between 8
and 9 ft downstream of the Gulf this morning. Elsewhere, gentle 
to moderate S to SW monsoon flow will persist across the offshore
waters of Costa Rica, Panama, Colombia, and Ecuador through Fri 

Remainder of the area...

A 1025 mb high pressure center is located near 32n128w is slowly
building SSE into the subtropics. Recent scatterometer data 
generally showed NE to E tradewinds of 10 to 20 kt across the 
waters S of 25n and W of 120w. This high pressure will shift 
slightly S through Tue and induce a freshening trade wind flow 
across the region S of 22n to the ITCZ and W of 110w. NW swell 
propagating across the baja offshore waters will also move into 
this area tonight to produce seas of 9-11 ft. The NW swell will 
continue to gradually decay through Tue night. However, 
increasing trade winds on the S side of the building high will 
compensate and keep seas around 8 ft in this area through mid 

A cold front is approaching the discussion area but is expected 
to stall just NW of 30n140w by tonight, then slowly weaken and 
lift N Tue. However, this front will introduce a new round of NW 
swell into the NW waters through the middle of next week. This 
swell will combine with wind waves generated by the fresh to 
strong trade winds S of 20n Wed night through Thu night to cause 
seas to build to between 10 and 13 ft by Fri night.



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