Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 241743
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
1243 PM EST Fri Feb 24 2017

.SYNOPSIS...
A low pressure system will track from the mid Mississippi
Valley this morning into the Great Lakes tonight with an
associated cold front pushing quickly east across the Ohio
Valley overnight. Warm southerly flow ahead of the front will
lead to unseasonably warm conditions today. Widespread showers
and thunderstorms are expected tonight as the cold front moves
through. More seasonable temperatures will spread into the area
for the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
No real change to the forecast today. Region will be warm
sectored today. Mid level cap should keep convection from
developing this afternoon. Will wait for the line of convection
to work in from the west.

Strong southerly in the warm sector will produce 25 to 35 mph
gusts. Highs in the low to mid 70s still look good.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
The cold front will push east across our area this evening and
into the overnight hours. As the front approaches, the cap will
continue to weaken and with better mid and upper level forcing
moving in from the west, expect fairly rapid shower and
thunderstorm development across our west early this evening,
then spreading east through late evening into the early morning
hours. Some of the higher res CAM models are indicating two
lines of pcpn developing across our west, one along a pre
frontal trough and then another along the cold front, before
eventually congealing into more of a single line across our
east through late evening and into the early morning hours.

Impressive deep layer shear values will spread in from the west
through the evening hours and this will be coupled with an
increase in both the 0-1 km and 0-3 km shear values as the front
approaches. This will support a primarily damaging wind threat
but with cooler air moving in aloft and increasing mid level
lapse rates, some hail will also be possible. Several of the
higher res models are also hinting at the possibility of a few
quasi-discrete cells early in the period across the west. This
coincides with a bit of an uptick in updraft speed/helicities
across western portions of our fa in the 23z-02z. This will
result in an isolated tornado threat through the early evening
hours. As the storms transform into more of a QLCS through late
evening, the severe threat will transition more to just a
damaging wind threat, although an isolated tornado will still
be possible with any stronger rotations within the line.

Temperatures will remain up ahead of the front but then begin to
drop off fairly quickly from the west later tonight as CAA
developing in the wake of the front. Lows tonight will range
from the mid 30s west to the mid 40s east. Some wrap around
moisture will work back into the area through the day on
Saturday as the mid level trough axis pivots east across the
region. This will result in the possibility of a few rain/snow
showers through the day. In addition, a fairly tight pressure
gradient combined with some continued low level CAA will lead
to gusty winds in the 25 to 35 mph range on Saturday.
Temperatures will also struggle to rise much, with readings
ranging from the upper 30s west to the upper 40s east.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Surface high pressure will be centered over Tennessee and
Kentucky Sunday morning allowing for temperatures in the mid to
low 20s. During the afternoon Sunday surface high pressure will
push east with clear skies slowly giving way to some cirrus in
the afternoon. This is thanks to a broad upper level trough
centered over Canada with pieces of energy rotating east through
the base of the trough. By Monday morning the next piece of
energy will approach the area from the west. The ECMWF and GFS
are slightly different here on a piece of energy that starts out
in Southern California on Sunday and eventually pushes east
across our area Monday. The ECMWF and GFS both weaken the energy
but the GFS holds the energy together slightly longer than the
ECMWF. This allows light precip to push into the area Monday
morning. The ECMWF solution just doesn`t have enough energy left
with the system to produce QPF. Looking at the soundings from
the GFS it looks like rain/ snow will be the likely p- type
starting off Monday before changing over to all rain Monday
afternoon. The ECMWF solution produces quite a different
solution though and have kept PoPs chance at best for now.

Monday night into Tuesday morning the GFS and ECMWF continue to
diverge on solutions with timing between the models moving out of
phase. Both models show an upper level disturbance across the
Western United States which amplifies and heads east across the
forecast area through the middle of the work week. The ECMWF is
slower and slightly weaker with the system compared to the GFS. The
ECMWF pushes a wedge of PV ahead of the system though and allows
rain to start Monday night while the GFS is now slightly more
delayed with the onset of precipitation. A warm front will then lift
across the area Tuesday allowing temperatures to climb close to 60
degrees again. A surface low will then form Tuesday into Wednesday
and push northeast towards Michigan with a cold front extending from
the low down to the Gulf Coast. The GFS being much quicker with the
energy has the cold front clearing the CWA Wednesday morning while
the ECMWF has the cold front clearing the area Wednesday evening.
The Canadian is a good compromise between the two and have trended
the forecast this direction.

For the end of the work week northwest flow will develop on the back
side of the trough axis only to have an upper level disturbance push
southeast towards the forecast area. As of now both the ECMWF and
GFS have the system more across our northeastern zones and therefore
have trended the chance of precipitation higher across the
aforementioned area.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
The forecast area will be firmly in the warm sector ahead of
deepening low pressure and a cold front to our west this
afternoon. Scattered cumulus with increasing mid/high clouds can
be expected. Winds will be gusty from the south in the upper 20s
to lower 30s knots.

For tonight, focus turns to the low pressure system and an
attendant cold front that is expected to sweep east across the
terminals. Widespread showers and the likelihood of
thunderstorms remains decent. Have included an MVFR conditional
TEMPO group for the best time frame to expect convection. As is
typical with thunderstorms, local IFR visibilities may occur
within the strongest thunderstorm cores. Region will eventually
become "dry slotted" late tonight behind frontal passage.
Ceilings should remain in the VFR range in the dry slot until
Saturday morning.

On Saturday, parent upper level trough will move east across the
Great Lakes and Ohio Valley. MVFR post frontal stratocumulus can
be expected. Ceilings will lower to MVFR at first before rising
back above VFR late in the day. A few rain and/or snow showers
will be possible, mainly near the northern terminals as some
post frontal instability will be in place.

OUTLOOK...MVFR ceilings and visibilities possible Monday,
Tuesday night, and Wednesday.

&&

.CLIMATE...
Record High Temperatures
Date     CVG           CMH                DAY
Fri 2/24 72(1930)      72(1961)           67(1930/1961)

February Record Highs

CVG 76 set 2/10/1932
CMH 75 set 2/26/2000
DAY 73 set 2/11/1999 and 2/25/2000

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...JGL
NEAR TERM...JGL/Sites
SHORT TERM...JGL
LONG TERM...Haines
AVIATION...Hickman
CLIMATE...



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