Aviation Forecast Discussions Data
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    VFR SKC across most of the area as of 0330Z. The
    exception is an area of IFR to LIFR in the central and south
    Willamette Valley. This has has been slowly expanding north and
    will likely impact KSLE by 05Z. Expect increasing IFR or lower
    conditions north of KSLE overnight. Meanwhile, mid and high level
    clouds associated with the leading edge of an approaching
    frontal system had reached the Washington coast near KHQM. There
    is a mass of stratus beneath these mid and high clouds and expect
    MVFR flight conditions to develop along the south Washington and
    north Oregon Coast by 06Z.
    A predominant mix of IFR and MVFR will cover the northwest half
    of the forecast area from 10Z through about 19Z Fri. IFR to LIFR
    will persist in the Willamette Valley south of KS12 through 10Z.
    Gradual improvement occurs after 10Z as a south surface wind
    helps to mix out the fog. The southern half of the area west of
    the Cascades will be in mainly MVFR conditions late tonight
    through Friday morning. The Central Cascades should hold on to
    VFR at least til 14Z Fri and then endure a 4-5 hour period of
    sub-VFR conditions.
    For detailed regional Pac NW weather information, go online to:
    KPDX AND APPROACHES...VFR SKC as of 0330Z, but am expecting IFR
    to develop around 07Z. The Tualatin River Valley will likely see
    LIFR a little earlier. A mix of IFR to MVFR holds through 10Z and
    then mainly MVFR until 19Z. Improvement to VFR after 19Z in the
    post-frontal air mass. Weishaar