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303
FXUS61 KILN 220207
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
1007 PM EDT Wed Jun 21 2017

.SYNOPSIS...
A weak front will remain stretched across the region today and
then lift north tonight. Tropical moisture will spread into the
area from the south on Thursday with a cold front dropping in
from the northwest Friday afternoon and night. Below normal
temperatures will ensue over the weekend into early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Isolated showers and thunderstorms are persisting into the late
evening along a boundary extending into Ohio. Expect chances to
continue through much of the overnight hours as the boundary
lifts slowly northeast.

Under cloud cover, warm advection, and winds above calm, low
temperatures will only fall into the upper 60s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
During the day Thursday Tropical Storm Cindy will head north
through LA/ TX. A shortwave will also push north up ahead of the
tropical storm and around the subtropical ridge. Thursday
morning into early Thursday afternoon will probably remain dry
out ahead of the shortwave. Later Thursday afternoon forecast
soundings start to destabilize with PWATs slowly ticking up. By
Thursday evening ML CAPE values on the GFS approach ~500 J/kg
with PWATs almost up to 2.00" (near or at the daily PWAT max).

The main concern will be the late Thursday through Friday
morning period as a frontogenetic band moves out ahead of Cindy
and interacting with high PWATs. Overall the pattern looks to
have similarities to a predecessor rainfall event (PRE). As
Friday morning evolves a potent upper level longwave trough axis
approaches from the west with the ILN forecast area moving into
a RRQ. The shortwave trough axis also extends from the
Minnesota/ Canada border towards the Gulf Coast with ILN being
east of the axis. A cold front will extend from northern
Michigan southwest towards northern Illinois. The CMC has an
axis of heavy rainfall extending from southern Illinois towards
our northwestern zones. The ECMWF has this axis across our
central zones. The GFS and NAM have this heavy rain axis across
our southern zones. Given the signals above have added the
mention of heavy rain into the forecast. Also have extended the
heavy rain mention to all zones of the HWO given the
uncertainty. This uncertainty is also highlighted in SREF plume
runs which shows a wide range of possible solutions of eventual
rainfall totals (or placement of the eventual band).

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Tropical moisture advects northeast ahead of the remnants of T.S.
Cindy with precipitable water values increasing to 2.3 inches over
the Ohio Valley. This tropical moisture will interact with a
southward advancing frontal boundary to produce widespread showers
and thunderstorms and the potential for heavy rain over ILN/s
southern counties. Due to this moisture rich environment with
favorable frontogenetic forcing will mention heavy rain in the
weather grids. Fridays temperatures will be a little below normal
with highs around 80s.

Model solutions in a little better agreement with main remnants of
T.S. Cindy staying south of ILN/s area and pcpn ending early
Saturday. Will diminish pops from northwest to south late Friday
night into Saturday. Temperatures to remain a little below normal
with Fridays highs ranging from the upper 70s northwest to the lower
80s southeast.

Mid level trof to develop over the Great Lakes with westerly flow
over the Ohio Valley. ECMWF solution sharper with this trof and
therefore offers a wetter solution. Will follow a blend of GFS and
Canadian, limiting any mention of pcpn to a slight chance of a
shower or thunderstorm to the far north Sunday afternoon. Cool
temperatures to continue with Sundays highs in the mid/upper 70s.

With the mid level trof lagging across the Great Lakes can not rule
out an afternoon shower mainly across the north Monday. Will limit
these pops to slight chance. Temperatures look to be about 10
degrees below normal with highs on Monday in the lower and middle
70s.

Surface high pressure to build across the Ohio Valley keeping the
region dry and cool Tuesday. Expect Tuesdays highs in the mid/upper
70s.

Return moisture on the back side of surface high pressure will lead
to a chance of thunderstorms Wednesday afternoon across the north.
Expect Wednesdays highs to be around 80.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Conditions are likely to remain VFR tonight as a frontal
boundary lifts northeast across the region. Isolated showers
that have developed in the vicinity of TAF sites should
dissipate this evening with loss of daytime heating. This will
leave SCT to BKN mid and high clouds through the overnight
hours.

Expect VFR to continue through the day Thursday in a humid but
weakly forced environment. Showers may occur in the vicinity of
all sites late in the forecast ahead of a massive system
approaching from the southwest.

At CVG near the end of their 30 hour TAF, forcing and moisture
will increase significantly as a cold front from the west begins
to interact with remnants of TS Cindy. Look for showers with
VCTS and MVFR ceilings to come into the picture after 00Z
Friday.

OUTLOOK...Thunderstorms possible Thursday night into Saturday
morning. MVFR ceilings possible Thursday night into Friday
night. Low level wind shear will also be possible early Friday
morning.

&&

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

&&

$$
SYNOPSIS...Haines
NEAR TERM...Coniglio/Haines
SHORT TERM...Haines
LONG TERM...AR
AVIATION...Coniglio