Scientific Forecaster Discussion
fxus61 Kiln 151120
Area forecast discussion
National Weather Service Wilmington Ohio
620 am 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/...
area of stratus continues to creep eastward across the
northwest counties early this morning. Latest satellite loop is
suggesting that it will affect mainly areas along and north of
I-70 early this morning before it begins to mix out during the
mid morning hours. At the other end of the fa, high clouds
associated with an area of pva in the confluence of the northern
and southern streams is continuing to pull eastward and
shouldn't really be a factor in the forecast for later today.
Surface high pressure will ridge into the region today. As
mentioned above, the stratus in the north is expected to
scatter out during the morning hours. Across the south mostly
sunny skies are expected. A backdoor cold front will drop across
Lake Erie later today. It might a spread some clouds late in
the period into central Ohio.
High temperatures today are forecast to range from the mid 30s
in west central Ohio to lower to mid 40s in the northern
Kentucky and the lower Scioto valley.
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 /11z Friday through Tuesday/...
area of stratus that has been slowly drifting east-southeast
from nrn in/Ohio has worked into kday. Latest satellite loop has
been showing some erosion on the leading edge. So kday should
experience the MVFR ceilings through about 15z, when the clouds
are forecast to scatter out. At kcmh, they could see a tempo
MVFR ceiling in the next hour or two. Klck looks too far
southeast to get a ceiling before the stratus mixes out. Kiln
could also see a tempo MVFR ceiling as a rouge area of clouds
slides to the east.
After the stratus mixes out, could see scattered cu throughout
Backdoor cold front is forecast to drop through Lake Erie this
afternoon. This should bring some broken clouds to the tafs
after 00z. The best chance will be at the northern tafs.
Outlook...MVFR/IFR cigs will be possible early Saturday morning.