Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 202019
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
319 PM EST Mon Feb 20 2017

.SYNOPSIS...
A warm and well above normal temperature pattern will continue
through Friday.  A weak frontal boundary will approach on
Tuesday and wash out over the region Tuesday night. An unsettled
pattern will be present Thursday through Friday night. A strong
cold front will move through Friday night.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure will be situated east of the area overnight
allowing for southerly flow to continue through the overnight
hours. In addition cloud cover will be on the increase as a weak
frontal boundary approaches. The southerly flow and increase in
clouds will allow for continued above normal temperatures.
Precipitation is expected to hold off through the night. The
increase in cloud cover overnight should help limit fog
development.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
Well above normal temperatures will continue through the short
term. A weak frontal boundary will approach the region Tuesday
and wash out over the area Tuesday night. Models continue to
disagree on precipitation coverage for the short term.

The pattern indicates that there will be two light areas of
precipitation one that moves into northwestern portions of the
forecast area and another that moves across the south and into
central portions of the forecast area.

Due to the expected precipitation coverage limited
precipitation chances to the chance or likely categories. As the
front washes out Tuesday night some patchy fog will be
possible. Added patchy fog mention to the forecast.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
An upper level low will break off from the main flow and head
towards Florida on Wednesday with 850 mb temperatures around 10
degrees C. By Thursday the inversion around 800 mb will start to
erode with a slight cooling in 850 temperatures. As the inversion
begins to weaken surface based instability will grow. Both the ECMWF
and GFS also show weak PVA moving over the area Thursday afternoon
into evening. Forecast soundings on the GFS show MU CAPE values
averaging ~600 J/kg while ML CAPE values are around 300 J/kg. There
is some dry air in forecast soundings which could help to limit
updraft growth but still think thunderstorms will be possible in the
afternoon. Previous model runs also had a stalled front across the
area Thursday afternoon but the latest GFS and ECMWF have the front
closer to the Ohio/ Michigan border.

Friday an upper level low will eject out of the midwest and head
east. ILN will be in the warm sector Friday with southwesterly flow
firmly established in the low levels. GFS forecast soundings have a
CAP forming around 800 mb Friday morning and holding firm until
Friday evening. Friday afternoon into evening the cold front will be
pushing into Indiana and approach the CWA border Friday night. As
the front approaches the CAP will erode with forecast soundings
completely saturating briefly. ML CAPE is forecasted to be around
700 J/kg with SFC- 1 km shear values around 35 kts. The LLJ will
also be strong with 50 kts forecasted at 850 mb. Due to the
mentioned above SPC has the area outlooked for Day 5. Looking at the
mean flow orientation (relative to the boundary) and magnitude a
linear feature looks to form along the front and push east.

Saturday morning the cold front will clear the CWA by 8 am with the
upper level low over northern Michigan. As the low deepens the
pressure gradient will continue to tighten. This mean winds could be
gusty Saturday with GFS forecast soundings showing gusts of 30 to 35
kts possible (via momentum transfer). Sunday surface high pressure
will move south of the region with 850 mb temperatures forecasted to
be around 6 degrees C below zero. This will help push high
temperatures for Saturday and Sunday back down into the 40s or near
normal for this time of year. Monday the upper level trough
amplitude will begin to modulate with another upper level system
approaching the western United States. The GFS and ECMWF differ here
with the GFS holding a baroclinic zone across the CWA while the
ECMWF lifts a warm front through the CWA.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
Visibilities continue to improve across the TAF sites and will
become VFR this afternoon. An increase in mid and high clouds
overnight should limit fog development tonight. Cannot rule out
some fog at the more favorable fog location KLUK earlier in the
night before more clouds move in. Rain showers are expected to
hold off until after the end of the TAF period, except for the
longer KCVG TAF.

OUTLOOK...MVFR ceilings are possible Tuesday night and
Wednesday.  Thunderstorms are possible Thursday and Friday.

&&

.CLIMATE...
Record High Temperatures
Date     CVG           CMH                DAY
Mon 2/20 72(1891/2016) 68(1891/2016)      69(2016)
Tue 2/21 70(1930)      71(1997)           68(1930)
Wed 2/22 71(1922)      70(1930)           69(1922)
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...Novak
NEAR TERM...Novak
SHORT TERM...Novak
LONG TERM...Haines
AVIATION...Novak
CLIMATE...


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