Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Wilmington Ohio
201 am EDT Friday Apr 18 2014

Synopsis...
milder temperatures expected tonight with a southerly flow observed
between retreating high pressure and an approaching weak front. A
few showers will be possible Friday as a weak front with limited
moisture pushes through the Ohio Valley. High pressure will settle
back in for the weekend offering dry conditions and mild
temperatures.

&&

Near term /until 6 am this morning/...
with temperatures right on the track of the previous
forecast...and with no other changes apparent in the expected
weather setup through sunrise...grid updates tonight were limited
to adjustments for current trends. Although some locations are
still in the upper 50s...light winds will combine with a dry
boundary layer to support strong cooling tonight.

Previous discussion >
middle/upper level flow to sharpen up with a trough developing across the
western Great Lakes by morning. Initial shortwave and associated
surface low to track through the Great Lakes and into southern Canada tonight
with southward trailing cold front slipping into Northwest Ohio by 12z
Friday. Forcing is weak and moisture is limited...so will limit
probability of precipitation to slight chance in far northwest around sunrise. Skies to start out
mainly clear and then will allow for an increase in clouds
overnight. Clouds will keep temperatures milder tonight with lows
from the middle 40s northwest to near 40 southeast.

&&

Short term /6 am this morning through Saturday night/...
split flow with northern stream trough passing through the Great Lakes
and upper low staying well south of our area over the Gulf states.
Weak surface cold front to pass through iln/S forecast area Friday. Upper level
support to our north...moisture is limited and low level
convergences is weak to start out and further weakens as the front
passes through and undergoes frontolysis. Will limit probability of precipitation to low chance
pop north and only slight chance south. Temperatures close to
normal Friday with highs ranging from the lower 60s northwest to the
upper 60s southeast.

Surface high pressure to build across the Great Lakes Friday night.
Clouds will decrease in the wake of weak front. Lows Friday night to
range from the upper 30s northwest to the middle/upper 40s southeast.

This surface high to control our weather on Saturday...providing dry
conditions and temperatures near normal. Highs to range from near 60
north to near 70 far south. Surface high to slide off to the east with
middle level ridging beginning to build in Saturday night. Skies will
be mainly clear with only some high level clouds spilling in.
Saturday nights lows to range from upper 30s NE to the middle/upper 40s
southwest.

&&

Long term /Sunday through Thursday/...
Sunday will be dry behind departing high pressure. Cold front
will approach from the west on Monday and then cross the area on
Tuesday. Models have become slower with the progression of the
front...and more instability is shown to develop. Therefore have
backed off a bit on timing of showers while adding a chance of
thunder.

For Wednesday and Thursday...generally dry weather is in store as
high pressure builds over the Great Lakes. A few showers may develop
on Thursday in isentropic lift on the back side of the high...but
probability of precipitation are below threshold to appear in the forecast.

Temperatures will vary in relation to the cold front. A southerly
flow ahead of the front and behind the initial high will combine
with solar radiation to bring temperatures into the low 70s most
locations on Sunday and Monday. Highs will slide mainly into the 60s
on Tuesday...then into the 50s and 60s Wednesday as cold advection
and clouds behind the front have their effect. Warm advection will
bring highs back to the 70s on Thursday.

&&

Aviation /06z Friday through Tuesday/...
VFR conditions are expected through the taf period. A weak cold
front will move through the taf sites on Friday. Moisture is
limited with this feature and therefore left precipitation mention
out of the tafs. The best chance for a shower would be middle day to
early afternoon at kday however due to the low probability have
left mention out of the taf at this time. Clouds will increase
across the taf sites on Friday however ceilings will remain VFR.

Outlook...MVFR ceilings and visibilities possible Monday into
Tuesday.

&&

Iln watches/warnings/advisories...
Ohio...none.
Kentucky...none.
In...none.

&&

$$
Synopsis...Arkansas
near term...hatzos/AR
short term...Arkansas
long term...coniglio
aviation...Novak