Area Forecast Discussion
Issued by NWS Wilmington, OH-- Remove Highlighting --
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FXUS61 KILN 220540
Area Forecast Discussion
National Weather Service Wilmington OH
140 AM EDT FRI JUL 22 2016
A large ridge of high pressure over the central portion of the
United States will bring hot and humid conditions to the Ohio Valley
through the weekend. A weak front will bring scattered showers and
storms as it lays across the region. A strong cold front will
bring more showers and storms for Monday with slightly cooler air
for the first half of next week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A few lingering light showers will completely dissipate over the
next hour, but expansive cirrus from earlier convection will
likely keep skies mostly cloudy for the rest of tonight. Another
MCS currently over southern WI will also add to our cloud cover
later tonight. Models continue to struggle with ongoing convective
activity across the region, though the HRRR has handled the short
term fairly well today. Recent HRRR runs show the WI MCS diving
south overnight and staying west of the ILN forecast area, which
lines up well with current radar loop and upper level winds.
However, the shortwave that triggered this activity will be riding
the mid level ridge into Indiana and western Ohio by Friday
morning and may generate some additional showers and storms
further east. This activity could impact the northern CWA by
daybreak, as suggested by the HRRR, RAP, ARW, and NMM. Synoptic
models are of course more muddled, but they do also support the
chance for showers and storms across our north late tonight.
Have increased cloud cover overnight and introduced chance POPs
across our north late. Also nudged up dewpoints a tad based on
latest trends, which will make for muggy overnight lows in the
upper 60s to lower 70s.
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
Heat and humidity will be the main focus through Friday and the
weekend, but a challenging forecast for potential convection is
also a part of the situation.
Temps and dewpoints on the rise and fairly confident that at
least most of fcst area will see heat indices reaching the 100
degree mark in the afternoon both Friday and Saturday. With 2
consecutive days of 100 have issued heat warnings for Hamilton
and Montgomery counties and advisory for rest of fcst area.
Biggest question mark is convection coverage and timing. Difficult
to pinpoint timing and coverage through fcst period. Have opted to
keep pops in the chance category for now but a bit higher than
previous fcst. SPC has marginal outlook which looks reasonable as
any widespread significant outbreak would not be expected in this
pattern. Any storms would be slow moving with mainly strong wind
gusts and heavy rain. Temps generally close to guidance through
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Sunday morning the long term will open up with mid-level ridging
stretching across the entire center of the central United States
from the west coast to the east coast. Over the next couple of days
several shortwaves will traverse the region bringing on and off
chances of showers and thunderstorms. This pattern will continue
through most of the extended with a slightly lower heights and
temperatures possible by the end of next week.
The main story for the beginning of the extended will be the heat
and humidity. 850 mb temperatures will again be around 20 degrees C
with high temperatures in the lower 90s forecasted. This working in
combination with dewpoints in the lower to mid 70s will put heat
index values in the lower 100s. During the day Sunday a weak
shortwave will move overhead bringing a chance of rain to the area
with the GFS and ECMWF being pretty similar with the strength and
position of the wave. During the day Sunday PWATs are forecasted to
rise above 2.00" at times and given widespread instability have
nudged PoPs upwards slightly. On Monday an upper level low will
swing east across the Hudson Bay bringing a weak front across the
area. Surface convergence is weak along the front and timing between
the GFS and ECMWF is slightly out of phase. The ECMWF is slightly
faster than the GFS with the GFS bringing the front through Tuesday
morning. The ECMWF bring the front through Monday evening. Have
leaned towards the ECMWF here.
Behind the front much drier air will filter in with PWATs less than
1.00". This will help to bring a temporary end in the precip until
Thursday. At the end of extended Thursday another shortwave will
approach the area bringing the chance of rain back to the area.
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --Expect VFR to continue for the most part. BR reducing visibility
at LUK is the exception. Otherwise, skies are mainly clear to
start. Thunderstorms to the northwest may reach DAY around 10z
while weakening. Thunderstorms may also occur near ILN around
12z, and near CVG and LUK around 14z. Will monitor radar trends
compared to models and amend TAFs to pinpoint time of arrival and
duration if necessary. Convection may also develop during
afternoon peak heating so have included VCTS at DAY ILN CMH and
LCK. Winds will generally be out of the west to southwest, with
speeds 12 knots or less.
OUTLOOK...Thunderstorms possible Saturday through Monday.
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-- Changed Discussion --OH...Heat Advisory from 10 AM this morning to 8 PM EDT Saturday for
Excessive Heat Warning from 10 AM this morning to 8 PM EDT
Saturday for OHZ061-077.
KY...Heat Advisory from 10 AM this morning to 8 PM EDT Saturday for
IN...Heat Advisory from 10 AM this morning to 8 PM EDT Saturday for
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