Area Forecast Discussion
Issued by NWS Wilmington, OH

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238
FXUS61 KILN 230559
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
1259 AM EST Thu Feb 23 2017

.SYNOPSIS...
A mild airmass will be over the region tonight. Showers will be
possible late tonight and Thursday when a warm front is
forecast to develop across northern Ohio. A strong cold front
will push through late Friday, bringing widespread showers and
thunderstorms.

&&

.NEAR TERM /THROUGH TODAY/...
Southerly flow will keep a good amount of low level moisture in
the region this evening and overnight ahead of an approaching
cold front. Some breaks may be found along and south of the Ohio
River this evening, but a general cloudy sky cover is expected
overnight and into Thursday.

Temperatures will see about a 5 degree or so drop from current
readings in the upper 50s and low 60s into the mid and upper
50s tonight.

Low clouds are expected to expand back southward overnight as
temperatures cool towards the dewpoints. With the abundant low
level moisture, fog is expected to develop again tonight.

A cdfnt will approach from the nw overnight and provide some
lift and an increased chance of scattered light showers.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
The cdfnt will reach the nw counties Thursday morning, before
stalling. Scattered showers will be possible on Thursday with
the low level convergence in the area, but there will be a
transition of better PoPs towards the northern counties by late
afternoon.

Morning clouds are expected to break during the afternoon
allowing temperatures to jump into the mid to upper 60s. A 70 is
possible in nrn KY. Records are possible at Columbus and Dayton.

The stalled front will begin to transition northward as a warm
front Thursday Night. A low chance of showers will remain
across the north, but the front will be drifting north taking
the better convergence with it, so left the mention of thunder
out.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Main focus in the immediate long term will be the potential for
severe storms Friday evening into early Saturday morning.

Upper level low will pivot northeast from the central Plains to
the western Great Lakes and western Ohio Valley Friday into
Friday night. As this occurs, heights will fall with the upper
level low while surface low pressure deepens as it travels
northeast from Iowa to northern lower Michigan. We will be in
the warm sector ahead of this system for most of daylight hours
on Friday. This will allow for unseasonably warm temperatures
and breezy conditions, along with a weak capping inversion.
Highs in the lower to mid 70s will threaten or break records at
the big three climate stations of KDAY, KCVG, and KCMH. Then,
the focus will shift to our west late in the day and during the
evening as strong upper level dynamic lift combines with low
level convergence with either the cold front front or a prefrontal
trof/low level convergent region to produce showers and
thunderstorms. Bulk shear, whether 0-3 km or 0-6 km, will be
sufficient for organized storms. The question almost always
lies with how much instability will be realized. At this time,
MLCAPES could approach or exceed 1000 J/KG MLCAPE across our
western zones during the evening, which will be plenty within a
strong wind regime. As such, SPC SWODY3 has our region in an
enhanced/slight risk for severe storms Friday night. Main threat
will be damaging winds, especially if a quasi-liner mesoscale
feature(s) form (QLCS?) to produce bowing segments. Will also
have to add the threat for large hail as mid level lapse rates
approach 8.0 to 8.5 C/km (steep), wet bulb zeros remain in the
favorable 7-8 kft range, and if some storms rotate, it will add
extra vertical motion due to a vertical pressure gradient
differential. Finally, can not rule out an isolated tornado,
especially if a renegade supercell should form ahead of the main
convective line, or with some embedded misocyclones possible
within the mesoscale convective line. Convection is expected to
clear our eastern zones between 06Z and 12Z Saturday. In the
wake of the cold front, low will drop to the upper 30s west to
the lower 50s east.

For Saturday into Saturday night, upper level low will rotate
across the Great Lakes. As pcpn ends across the east, CAA along
with some upper level lift will bring some instability showers
to the area, with the best chance expected across our northwest
zones during the afternoon/early evening. Showers will mix with
snow later in the day and evening as colder air continues to
filter into our area. The threat for pcpn will end Saturday
night as the upper level low moves east and surface ridging
builds in from the west. It will be windy on Saturday as a
decent pressure gradient teams up with CAA/momentum transfer to
bring wind gusts in the 30 mph to 40 mph range. Temperatures
will exhibit a slow fall during the day. Lows will bottom out in
the mid to upper 20s by Sunday morning.

Long range operational models are in fairly good agreement for
the remainder of the extended, with some timing and strength
issues to hash out.

Sunday will see a reprieve in terms of a pcpn threat with high
pressure moving east. Highs in the lower to mid 40s will be
seasonal for late February.

The next weather system is then poised to affect the region
Sunday night into Monday night. Rain, or a chance of rain/snow
north will occur Sunday night into Monday with just rain
expected all locations by Monday night.

A stronger system is then expected during the Tuesday/Wednesday
time frame. Warmer, moist air will eventually bring the
likelihood of showers with embedded thunderstorms. Highs will
push to above normal readings in the 50s and 60s.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
TAFs to be affected by a cold front approaching from the
northwest. Low level moisture increasing on a southerly flow is
forecast to converge ahead of the front this morning, producing
MVFR conditions and isolated rain showers. Observations close to
TAF sites are beginning to show MVFR which lends some confidence
to the early part of the forecast. MVFR is expected to persist
into the afternoon before ceilings lift above 3000 ft. A return
to MVFR could occur late in the forecast, aided by additional
moisture advection to the south of the strengthening front which
will be lifting north to Lake Erie as a warm front. Winds are
forecast to stay under 10 knots out of the south to southwest.

OUTLOOK...Thunderstorms are possible Friday and Friday night.
MVFR ceilings and vsbys are possible Saturday and Monday.

&&

.CLIMATE...
Record High Temperatures
Date     CVG           CMH                DAY
Thu 2/23 72(1985/1996) 66(1906/1985) 68(1985)
Fri 2/24 72(1930)      72(1961)      67(1930/1961)

&&

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

&&

$$
SYNOPSIS...Coniglio/Sites
NEAR TERM...Franks/Sites
SHORT TERM...Sites
LONG TERM...Hickman
AVIATION...Coniglio
CLIMATE...



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