Scientific Forecaster Discussion
fxus61 Kiln 210315
Area forecast discussion
National Weather Service Wilmington Ohio
1015 PM EST Mon Nov 20 2017
dry weather will continue tonight into the first part of Tuesday
as southerly flow increases on the back side of retreating high
pressure. A weak weather disturbance will push east across the
region Tuesday afternoon into Tuesday night bringing the chance
for a few showers. Dry conditions are then expected through
Friday before another disturbance results in a slight chance for
showers on Saturday.
Near term /through Tuesday/...
the center of a large surface ridge will continue building east
off the Carolina coast overnight. A southerly gradient will
increase overnight on the back side of this retreating high.
Initial batch of high level clouds moving east across the Ohio
Valley to thin some with more cirrus upstream to thicken back
up toward sunrise. Overnight lows generally expected in the
lower to middle 30s.
Short term /Tuesday night/...
a mid/upper level trough axis will pivot east across the Great
Lakes Tuesday into Tuesday night. Models have continued to
trend a little farther south with this feature. While the deeper
moisture will remain fairly marginal, there may be enough for
some scattered shower activity to develop through late
afternoon across mainly our northwest. A chance of showers will
then swing east across much of the rest of our area through the
evening hours, with the best chance being across our north.
Southerly flow ahead of this should help push temperatures up
into the upper 40s and 50s for highs on Tuesday. As a result,
any pcpn should remain mainly rain showers. However, as some
cooler air starts to work in behind the system, forecast
soundings are suggesting perhaps a brief mix across our north
before the pcpn ends.
Long term /Wednesday through Monday/...
period will feature a lack of strong forcing and deep moisture,
probably resulting in below normal precip.
High pressure and dry weather will be moving in on Wednesday behind
a cold front, pushed by a broad northwest flow aloft. Though the
atmosphere will be dry overall, clouds may increase Wednesday night
until the axis of an upper trough moves through on Thursday. Expect
mainly clear conditions Thursday night and Friday as the high
settles to the North Carolina coast.
For Friday night and Saturday, a rather potent surface low over
southern Canada, driven by a sharp upper trough, is forecast to push
a cold front to the Ohio Valley, bringing increasing clouds and a
chance of showers. A few snow flurries may mix in toward the end of
the event on Saturday night. High pressure and dry air are expected
to follow the cold front for Sunday and Monday.
Temperatures will vary with respect to advection patterns associated
with the cold fronts. Chilly readings in the upper 30s to lower 40s
Wednesday behind the first cold front are expected to rise through
the 40s on Thursday and Friday before reaching the lower 50s on
Saturday under gradual but persistent warm advection on a southwest
flow. After the next cold front passes Saturday night, look for
highs mainly in the 30s Sunday and Monday due to cold advection on a
Aviation /03z Tuesday through Saturday/...
airmass is dry with only high level clouds expected to stream
across the taf sites overnight. Low level jet increases
overnight ahead of mid level S/W digging southeast into the
Great Lakes. This low level jet could lead to some low level wind shear late
tonight into Tuesday morning. Otherwise, VFR conditions are
expected through the taf period with clouds thickening ahead of
an approaching surface cold front late in the day Tuesday. Have
indicated a wind shift to the northwest with clouds down to 5000
feet late int he kcvg 30 hour forecast.
Outlook...no significant weather expected.