Aviation Forecast Discussions Data
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(EXTRACTED FROM FXUS64 KEWX 031402 AAA)


     /12TAFs/
    A weak line of SHRA will move east over KSAT/KSSF in the next few
    hours and have TEMPO SHRA at those sites 12Z-15Z. Otherwise, at the
    I-35 sites, LIFR/IFR persists much of the morning before rapidly
    mixing out to VFR around midday. LIFR/IFR redevelop late this
    evening into overnight. Southerly winds of less than 10 KTs prevail.
    
    At KDRT, VFR and east to southeast winds of 5 to 10 KTs prevail today
    through tonight.
    
    PREV DISCUSSION... /ISSUED 211 AM CST Fri Dec 3 2021/
    
    SHORT TERM (Today through Saturday)...
    
    Areas of fog with patchy dense fog have developed along and east of
    US 281. Have maintained the Dense Fog Advisory through 9 AM when it
    mostly dissipates. Only patchy fog is expected elsewhere. An upper
    level shortwave trough currently over Far West Texas into the Big
    Bend moves over Central Texas today. Forcing by this trough of an
    unseasonably moist and weakly unstable airmass will generate showers
    and thunderstorms. However, capping lingers keeping coverage very
    isolated. Area radars confirms this by currently showing showers
    from the Edwards Plateau to along the Rio Grande. The unseasonably
    moist airmass remains as the trough moves east of our area. Expect
    another round of fog overnight into Saturday morning. A weak cold
    front stalls just north of the Hill Country and our Central Texas
    counties while a dryline briefly moves into Val Verde county
    Saturday afternoon. While the low level jet, front, and dryline
    could generate showers, they will be quite isolated. For now, will
    keep POPs out of the forecast for tonight into Saturday. A southerly
    lower level flow prevails keeping temperatures well above normal in
    the short-term.
    
    LONG TERM (Saturday Night through Thursday)...
    
    Semi-zonal flow aloft will be in place across much of the southern
    CONUS on Saturday evening, although a shortwave is forecast to
    impact portions of TX overnight. Models have generally backed off on
    the strength of this wave over the past couple of runs, though
    there's still a very low chance for isolated showers with a rumble of
    thunder or two across the Hill Country. Will continue to leave
    mention out of the forecast given model trends, particularly in the
    NAM. The overnight hours will otherwise feature continued warm, humid
    conditions with fog and stratus development similar to what we've
    been experiencing the past several nights. During the day Sunday,
    mostly cloudy skies are likely to prevail as model soundings depict a
    relatively thick high cloud layer embedded in moist SW flow off the
    Pacific. Nonetheless, highs will still reach the 70s to low 80s.
    
    A relatively strong trough will push into the north-central CONUS
    Sunday evening, with sfc cyclogenesis progged across the Great
    Lakes. A separate cutoff low is likely to remain well to our west
    near Baja California, although the latest ECMWF indicates a weaker
    trough, not closed off and located in closer proximity to south-
    central TX. This feature will be more important for our forecast on
    Tuesday. For Monday, expect a relatively strong cold front to push
    through quickly in the morning hours, with a few showers and
    potentially a thunderstorm possible prior to about noontime, mainly
    along and east of I-35 where deeper moisture will reside. A tenth of
    an inch of rainfall accumulation is probably about the best we can
    expect. Breezy north winds and cooler daytime highs mainly in the
    60s appear likely behind the front.
    
    On Tuesday, the aforementioned closed low looks to open up and
    traverse TX ahead of a much deeper trough digging south along the
    west coast. Could see some showers and a thunderstorm or two during
    the day with this, but again we're not expecting a big rainmaker at
    this time and any rain at all is no guarantee. Temperatures may warm
    a few degrees compared to Monday, although temperature uncertainty
    increases significantly. We may well see highs remain in the 60s
    through Wednesday as another northerly wind shift returns for
    midweek as the next trough axis moves in. Most signs point towards
    better rain chances staying well off to our east with each of these
    systems. Another warm-up looks poised to begin next Thursday. With
    no rain forecast over our western areas that need it most, continued
    gradual expansion and degradation of drought status is likely.