Scientific Forecaster Discussion
fxus61 Kiln 151938
Area forecast discussion
National Weather Service Wilmington Ohio
238 PM EST Fri Nov 15 2019
a backdoor cold front will slip south into the region tonight,
bringing another round of clouds. Temperatures will remain
below normal through the weekend as cold air is reinforced a
little behind the front. Dry weather is anticipated through the
weekend, although clouds will likely remain plentiful.
Near term /until 6 PM this evening/...
a narrow, southwest to northeast oriented axis of stratus is
pushing slowly southeast across central portions of our area
this morning. Expect this to gradually dissipate as we progress
through late morning/early afternoon as surface high pressure
continues to build into the region. Temperatures will remain
below normal today with highs ranging from the mid 30s in the
northwest to the mid 40s across the southeast.
Short term /6 PM this evening through 6 PM Saturday/...
the weak cold front will drop into the area tonight and wash
out. Models are inconsistent with how much the clouds will hold
together tonight. Went with a middle of the Road forecast and
went partly cloudy. Temperatures are forecast to drop down into
the lower to mid 20s tonight.
On Saturday, there will be surface high pressure centered over
the St. Lawrence River valley, with an extended ridge axis back
across the eastern Great Lakes into nrn Indiana. This will
continue the dry weather for the region, but also the below
normal temperatures. Highs Saturday might be a degree to two
warmer, ranging from the upper 30s to mid 40s.
Long term /Saturday night through Thursday/...
on Saturday evening, surface high pressure will be centered in
southern Quebec, extending southeast through the Ohio Valley and
even as far as the lower Mississippi Valley region. The Ohio Valley
will be in somewhat of a weakness in the mid-level flow, in a
section of the weather pattern that will be somewhat stagnant to
start, before upstream troughing begins to move into the area late
in the weekend. The coldest temperatures through the entire forecast
period are expected to occur on Sunday morning, with min temps in
the upper teens to mid 20s. With clear skies and light winds,
radiational cooling conditions should be quite favorable, so the
going forecast will remain slightly below the model consensus.
From late Sunday through about Wednesday, there is high confidence
in a general pattern of broad-scale troughing across the eastern
half of the conus, including the Ohio Valley region. Where the
forecast remains much lower in confidence is in any specifics
regarding shortwave propagation through the large trough, including
concerns with both timing and placement of the waves. As was
included in the previous forecast, a blended model / ensemble
approach suggests that Tuesday may have the greatest overall
probability of precipitation through this period, though the reality
is that it would be impossible to fully declare any part of the
period from early Monday morning (with the initial wave) through
Tuesday night (as the trough begins to move away) as certain to be
dry. Until the models can find some consistency with the shortwaves,
pops will be kept in just for Tuesday, and held at 20 percent.
A brief period of ridging is expected on Wednesday and early
Thursday, in advance of what both GFS/European model (ecmwf) solutions are
advertising as a fairly well-defined trough and associated cold
front later on Thursday. Regarding this feature, pops remain in the
30-40 percent range, given the strong model agreement (but also
factoring in the distance out in time).
Temperatures are forecast to remain below normal through the
extended period -- generally around 4-8 degrees below normal (lower
to upper 40s) in the sun-Mon-Tue time frame. As the mid-week ridging
builds in, some additional warming is expected on Wednesday and
Thursday, which may bring temperatures to the upper 40s / lower 50s
(close, if just below normal).
Aviation /18z Friday through Wednesday/... low clouds have
finally pushed away from the terminals and mostly burned off.
Latest satellite loop shows VFR conditions will continue through
the rest of the day.
However, there is currently another area of stratus heading
south behind a back door cold front near the Northern Ohio
border with lower Michigan. These low clouds will head south
through the afternoon and evening, bringing MVFR ceilings to all
terminals overnight on the heels of a wind shift out of the
northeast direction. Cannot rule out an brief dip into IFR
thresholds by early morning; though confidence is low, so stayed
with lower MVFR for now.
Dry air and slow heating should erode low clouds from northeast
to southwest late Saturday morning. Based on persistence of
moisture in most guidance, along with unfavorable wind direction
for eroding low clouds, have lower confidence on bringing
return of VFR conditions late Saturday morning.
Otherwise, VFR conditions should continue through end of taf
period at cvg.
Outlook...nothing significant expected at this time.