Rain last night into
the initially dry low-level air caused a temperature drop to 32F, with even
some freezing rain reported. The rain was heavy at times, with a total of 0.43”.
It then warmed up at the last minute this afternoon to 49F with a bit of late
afternoon sunshine, with the low-level cold air being much slower to get
scoured out than modeled, as often occurs with cold air damming. It might get a
bit warmer this evening with any downsloping flow or if the showers currently
over Kentucky move over Lynchburg and help mix warmer air aloft down to the
surface.
The robust batch
of showers could lead to some rain near the beginning tonight (Friday 06z),
though they will be weakening given the stable cold low-level air that hasn’t
been completely scoured out yet, waning instability at night, and downsloping.
Still, there may be enough left for up to a few hundredths of an inch. Tomorrow
will be very much like day 1, with cold advection but also downsloping
northwesterly winds off the Appalachians, with sunny skies. This will lead to
temperatures being well above model guidance again and the winds aloft mixing
down to the surface, perhaps up to ~15 kt or so. The models' mixed boundary layer extending only up to ~925 hPa appears to be unrealistically shallow given the full sunshine and downsloping wind. Winds turn to northeasterly
tomorrow evening and weaken with very dry air and clear skies, leading to rapid
radiational cooling until a couple of hours before the end (maybe around 04z
Saturday), when mid-level clouds will increase in advance of another
disturbance, which will stop the radiational cooling. Still, the low will
likely occur just before the clouds move in, with the colder air mass in place
there. It might still drop to or below model guidance even after warming up to
much warmer than models during the daytime tomorrow, given the good radiational
cooling tomorrow evening, like for day 1.
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| Source: PivotalWeather |
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| Source: PivotalWeather |
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