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    Eastern North Pacific Tropical Weather Discussion

    AXPZ20 KNHC 062120
    Tropical Weather Discussion
    NWS National Hurricane Center Miami FL
    2120 UTC Fri Dec 6 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.
    Gulf of Tehuantepec Gale Warning: A cold front that currently
    extends across the NW Gulf of Mexico will continue moving SE 
    through Sat, and high pressure will build over eastern Mexico 
    behind the front. The enhanced pressure gradient will support 
    gale force gap winds over the Gulf of Tehuantepec from late 
    tonight through Sat night. Seas will peak between 12-14 ft 
    downstream of the Gulf on Sat night, then subside on Sun as the 
    pressure gradient weakens and wind speeds diminish to fresh to 
    strong speeds. Looking ahead, another gale force gap wind event 
    could affect the Gulf of Tehuantepec Wed and Wed night as a 
    stronger cold front crosses the Gulf of Mexico.
    See latest NWS High Seas Forecast issued by National Hurricane
    Center under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or at website for more details.
    The monsoon trough extends from 06N77W to 07N90W to 06N108W to
    08N114W. The ITCZ continues from 08N114W to 10N130W to beyond 
    09N140W. Scattered moderate isolated strong convection is noted
    within 180 nm of the monsoon trough east of 86W. Scattered
    moderate convection is occurring from 03N to 07N between 104W 
    and 108W. 
    Please see the Special Features section above for more details on
    the Gulf of Tehuantepec Gale Warning.
    Earlier scatterometer data showed fresh to locally strong NW 
    winds across the central and southern Gulf of California between
    a low pressure trough over western Mexico and a high pressure 
    ridge over the Baja California offshore waters. These winds will 
    persist through Sat, then diminish to moderate speeds on Sun.
    Elsewhere, light to gentle winds prevail across most of the 
    offshore waters, except for moderate northerly winds over the 
    Gulf of Tehuantepec. 
    Large NW swell will enter the Baja California Norte waters Sat, 
    with offshore seas building to 8-11 ft by Sat night. This swell 
    will continue spreading SE across the region Sat night through 
    Sun night, then decay Mon into Mon night. The pressure gradient 
    over Baja California will strengthen early next week, resulting 
    in fresh northerly winds offshore and over the Gulf of California.
    The latest GOES-16 satellite imagery and available lightning data
    reveals scattered moderate to strong thunderstorms near the 
    monsoon trough over the offshore waters of Costa Rica, Panama, 
    and Colombia. Locally stronger winds and higher seas can be
    expected in and near thunderstorms. 
    Strong NE to E winds will pulse across and downstream of the 
    Gulf of Papagayo through Wed, with seas peaking between 8-9 ft 
    downstream of the Gulf each morning. Fresh SW winds off the coast
    of Colombia will diminish by Sat night. Otherwise, gentle to 
    moderate S to SW monsoon flow will persist across the offshore 
    waters of Costa Rica, Panama, Colombia, and Ecuador during the 
    next several days.
    A cold front extends across the NW waters from 30N128W to 27N131W
    to 23N140W. Recent scatterometer data indicates moderate to fresh
    W winds prevail from 28N to 30N west of the front, with stronger
    winds noted north of the forecast area. An 18 UTC altimeter pass
    highlights seas of 20-21 ft near 30N134W, with 8-12 ft seas in 
    NW swell extending SE to 26N133W. This front will continue moving
    eastward across the northern waters tonight, then stall and 
    weaken west of 120W Sat into Sat night. Very large NW swell 
    associated with this system will continue propagating SE through 
    the weekend. Seas will remain greater than 12 ft over the 
    northern waters through Sat, then subside Sat night through Sun.
    Looking ahead, another cold front will approach the NW portion of
    the discussion area on Mon, introducing another set of NW swell 
    into the NW waters through the middle of next week.