Area Forecast Discussion
Issued by NWS Wilmington, OH
FXUS61 KILN 241754
Area Forecast Discussion
National Weather Service Wilmington OH
1254 PM EST Tue Jan 24 2017
Precipitation will move east out of the area by this afternoon
as low pressure pulls east. Weak high pressure will then build
into the area this afternoon. Rain chances return for Wednesday
as another low pressure system approaches the region.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Patchy light drizzle/light rain is lingering a little longer
across our eastern zones this morning. Thus, have kept a slight
chance of this going until noon.
Otherwise, by afternoon, a surface ridge will begin to build
into the region from the west. Low level moisture in NAM and
GFS forecast soundings remains though with some hints of partial
clearing shown. With 850 mb temperatures and 1000/850 mb
thicknesses slowly climbing expect high temperatures in the mid
to upper 40s.
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
Tonight surface low pressure will move into Iowa with WAA
commencing in the low levels. It looks like that most of Wednesday
morning before sunrise will remain dry as the best isentropic
upglide will be in Michigan. Forecast soundings also indicate a
good amount of dry air remaining across the area. Wednesday
afternoon a warm front will wash north across the area allowing
dewpoints to rise into the middle 40s. At the same time a LLJ will
begin to move overhead. Looking at the GFS/ ECMWF/ NAM low level
convergence doesn`t look overtly impressive. Still though the GFS
and ECMWF have some light precip forming. For now have left a low
chance of precipitation in the forecast for Wednesday afternoon
as forecast soundings on the NAM and GFS don`t fully saturate
(dry air intrusion ~800 mb).
The surface low will then head east across central Michigan
dragging a cold front across the area Wednesday evening. Global
models are in fairly good agreement with having the front
approaching the IN/ OH border around 0z Thursday. The cold front
is then forecasted to push through the entire area by 6z Thursday.
Rain chances with the frontal passage itself look only slightly
better as western zones again have dry air present in forecast
soundings. Further east forecast soundings do saturate up to
around 600 mb or so so have kept higher chances of precipitation
Thursday morning behind the cold front, temperatures will begin
to fall with 850 mb temperatures collapsing to around 6 degrees
below zero (GFS has warm air lagging slightly further behind
compared to NAM/ ECMWF). The net result of this will be steepening
low level lapse rates. Also low level moisture will be on the
increase meaning the chance of snow showers will return to the
area. Thursday afternoon surface temperatures will likely be above
freezing but given 850 mb temperatures approaching 8 degrees below
zero have kept the p-type mostly snow (possible a rain/ snow mix
across the far southeast).
Thursday night into Friday morning the upper level low that
brought the surface cold front through the area will pull
northeast with heights rising out across the western United
States. This will allow a couple of pieces of energy to continue
to pull south while also keeping temperatures near normal Friday
morning. Snow showers should diminish in coverage Thursday night
into Friday morning but with lapse rates remaining steep have kept
the chance of precipitation in the forecast.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A broad upper level trough will be in place across the eastern
United States through the weekend. Several weak embedded short waves
within the broader trough will drop down across the Great Lakes
region Friday into Saturday. The combination of these and continued
cold cyclonic low level flow will result in the threat of at least a
few snow showers Friday and Saturday so will allow for some slight
chance pops at times both days. A stronger short wave will help
sharpen up the trough heading into Sunday which will likely lead to
some better chances of snow showers through the end of the weekend.
Expect dry conditions for Monday as mid level short wave ridging
briefly builds across the area. With the upper level trough and a
cooler airmass in place, temperatures will remain a few degrees
below normal trough the end of the period with highs mainly in the
low to mid 30s.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A surface ridge will build into the region from the west by
this evening, and then it will exit to the east overnight.
Persistent stratocumulus deck is forecast to erode by this
evening into early morning as WAA begins ahead of the next
weather system. Mainly MVFR ceilings are expected to rise to VFR
for a period.
For Wednesday, low pressure and its attendent cold front will
push east into the western Great Lakes and Ohio Valley. Low
level moist, WAA will bring MVFR ceilings back to the region
during Wednesday morning. A few showers may develop late in the
day ahead of the front. Winds will also increase from the south
and will become gusty up to 25 knots.
OUTLOOK...MVFR ceilings possible Wednesday night through