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Information is from the NWS Wilmington, OH Office


ILN Area Forecast Discussion/SKEW-T

FXUS61 KILN 112025
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
325 PM EST Mon Nov 11 2019

.SYNOPSIS...
Rain will change to snow this evening as a low pressure system
continues to influence the area before moving northeast toward
southern New England. Scattered flurries or isolated snow showers
will be possible on Tuesday as a strong mid level trough moves
across the Great Lakes. It will be very cold for early November.
Arctic high pressure will build into the region Tuesday night,
moving east of the area on Wednesday. It will remain very cold.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A large scale mid level trough will dig southeast into the Great
Lakes tonight while an associated low pressure and a cold front
move through the region. Large scale ascent with the mid level
trough will combine with low to mid level frontogenetic forcing,
resulting in widespread pcpn this evening. Pcpn will change
from rain to snow as much colder air moves in from the
northwest. There could be a brief period of sleet or freezing
rain as warmer air aloft lags a tad slower from the colder air
undercutting it at the surface. Winds will be gusty from the
north then northwest. Snowfall amounts of 2 to 4 inches still
look good for west central Ohio, with 1 to 3 inches elsewhere.
Most of the snow will fall on grassy and elevated surfaces as
road temperatures will take some time to cool below freezing. A
Winter Weather Advisory remains in effect until 8 am Tuesday
morning. Pcpn will taper off from northwest to southeast
overnight as the frontogenetic forcing moves off to the east.
Thus, pcpn will eventually taper off to a few snow showers or
flurries. Lows will range from the mid teens across east central
Indiana to the upper teens to the lower 20s elsewhere.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Large scale mid level trough will traverse east across the Great
Lakes on Tuesday. CAA and lingering low level moisture in the
form of stratocumulus will keep skies partly to mostly cloudy.
With the cloud layer intersecting the favored dendritic growth
zone, can not rule out an isolated snow shower or a few
flurries in the shallow unstable cloud layer. It will be very
cold for early November. In fact, high temperatures may occur
at midnight. Highs will range from 25 to 30 degrees. These may
end up setting record low Max values for November 12. Please see
climate section below.

For Tuesday night, Arctic high pressure will build into the
region. Stratocumulus clouds will scatter, being replaced by
some mid and high level clouds from the northwest late. The high
will build right on top of the area. Thus, where snow cover
remains decent enough, good radiational cooling will occur.
Currently have lows ranging from the single digits north to the
mid teens south. These could go colder if skies stay clear
enough overnight. Record lows will likely be tied or broken for
November 13. Please see climate section below.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
On Wednesday morning, surface high pressure will be departing
the Ohio Valley to the northeast, moving into the mid-Atlantic
and northeastern states by evening. A very dry air mass will be
in place across the southeastern states and lower Ohio Valley,
but much greater deep-layer moisture will be moving southeast
from the upper Midwest. The primary forecast concern late
Wednesday night into Thursday is with a shortwave moving across
the Great Lakes, associated with this area of moisture, and also
associated with a weak cold front that will be essentially
washing out as it approaches the Ohio Valley. From a modeling
perspective, the situation with this system has been a contrast
between weaker/northerly ECMWF solutions and wetter/southerly
GFS solutions. Recent GFS runs have trended toward the ECMWF,
and upper jet positioning seems to support that precipitation
will be more likely further north as well. Thus, the dry
forecast has been kept -- with precipitation generally expected
to remain no further south than northern IN/OH.

The forecast for the remainder of the extended forecast period
will also remain dry. After the shortwave passes on Thursday,
the Ohio Valley will be in sort of a weakness of the 700mb flow,
transitioning to broad/weak ridging over the weekend. By
Sunday, more active weather appears to be setting up along the
coast (with low development southeast of the Carolinas) and over
the upper Mississippi Valley (as a trough develops east of the
mountains). The Ohio Valley looks to remain comfortably in
between any of this activity through at least Sunday, and
possibly into the week depending on how exactly the broad-scale
flow evolves.

Following the very cold period Tuesday and Tuesday night, a
gradual rebound in temperatures is expected through the rest of
the forecast period. Still under some influence from the surface
high on Wednesday, max temperatures will remain about 20
degrees below normal -- ranging from upper 20s to mid 30s. It
will not be until the Sunday/Monday time frame that temperatures
are expected to return to normal.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Low pressure was located between KDAY and KCMH early this
afternoon along a frontal boundary. A large scale mid level
trough will continue to dig into the Great Lakes this afternoon
and evening. Meanwhile, an embedded disturbance across the
region will continue to lift northeast through the same period.
The low will deepen some as it moves toward western Pennsylvania
by 00Z. Large scale ascent with the digging mid level trough and
low level forcing developing on the back side of the low will
allow precipitation to rapidly develop from west to east across
the region. Meanwhile, CAA will filter into the region from the
northwest. This will allow for rain at the onset. The rain will
then mix with snow (perhaps a brief period of sleet or freezing
rain) before changing to all snow as temperatures fall below
freezing during the evening. There should be a decent period of
accumulating snow. The described weather scenario will result
in rapidly deteriorating conditions with all locations
eventually experiencing IFR/LIFR conditions. Winds will shift to
the north between 10 and 15 knots with gusts between 20 and 25
knots.

For the overnight period, snow will move east and taper off to
a few snow showers in the strong CAA behind the departing low.
Visibilities outside of snow showers will return to VFR with
MVFR ceilings remaining (stratocumulus deck between 1000 and
2000 feet). Gusty northwest winds will continue to around 20
knots.

On Tuesday, very cold Arctic air will be in place across the
region. Low level CAA stratocumulus and some influence from Lake
Michigan will keep isolated snow showers or scattered flurries
in the forecast for most of the day. Winds will remain gusty
from the northwest. Ceilings should gradually become VFR during
the afternoon hours.

By Tuesday night, high pressure will build into the region.
Stratocumulus should scatter as well as the end of isolated snow
showers or flurries.

OUTLOOK...No significant weather expected.

&&

.CLIMATE...
Tuesday and Wednesday temperatures will exceed or
be close to exceeding record values.

Tuesday Record Low Max Temperatures
Cincinnati 30 in 1932
Columbus 30 in 1920
Dayton 30 in 1920

Tuesday Max Temperatures
Cincinnati 29
Columbus 29
Dayton 26

Wednesday Record Low Temperatures
Cincinnati 14 in 1976
Columbus 14 in 1911
Dayton 13 in 1986

Wednesday Forecast Low Temperatures
Cincinnati 13
Columbus 13
Dayton 10

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Winter Weather Advisory until 8 AM EST Tuesday for OHZ045-046-
     051>056-060>065-070>074-077>082-088.
     Winter Weather Advisory until 8 AM EST Tuesday for OHZ026-034-
     035-042>044.
KY...Winter Weather Advisory until 8 AM EST Tuesday for KYZ089>100.
IN...Winter Weather Advisory until 8 AM EST Tuesday for INZ050-058-
     059-066-073>075-080.

&&

$$
SYNOPSIS...Hickman
NEAR TERM...Hickman
SHORT TERM...Hickman
LONG TERM...Hatzos
AVIATION...Hickman
CLIMATE...


Skew-T

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