Area Forecast Discussion
Issued by NWS Wilmington, OH-- Remove Highlighting --
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FXUS61 KILN 200523
Area Forecast Discussion
National Weather Service Wilmington OH
123 AM EDT WED JUL 20 2016
Surface high pressure will allow for dry conditions through
Thursday night. Thunderstorm chances return to the forecast for
Friday with an unstable airmass. Heat and humidity will build
through the week with the warmest temperatures expected from
Friday through the weekend.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Surface high pressure centered over the Great Lakes will continue
drifting east across the forecast area overnight, resulting in
calm or very light veering winds. An MCS currently over central
Illinois will likely stay west of our area overnight, with
current trajectories taking it south/southeast towards the
Paducah/Evansville area. However, the 19.18Z and 20.00Z NAM runs
have it brushing the far western edge of our forecast area just
after daybreak Wednesday. Recent HRRR runs also show some
convective activity breaking off the eastern edge of the main MCS
along a boundary of some sort, then weakening as it marches
eastward, reaching eastern Indiana around 14-15Z Wednesday. Not
sold on this scenario and have kept the forecast dry, but it is
within the realm of possibility. If this would happen to occur,
activity would be weakening and would just expect some showers
affecting our Indiana counties. Otherwise have bumped up dewpoints
a tad overnight as well as cloud cover across our southwest owing
to cirrus blowoff from the MCS. Low will range from around 60 east
of Columbus to upper 60s in our southwest.
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
Surface high pressure across the area on Wednesday will push to
the east on Thursday. There is northwest flow aloft, however any
disturbances are weak and generally east or west of the area. With
no clear preciptiation signal, decided to go with a dry forecast
at this time.
Wednesday will be the cooler of the two days. As the high shifts
to the east southerly flow will increase on Thursday and warmer
air will move into the area. Heat index values will approach 100
across southwest portions of the forecast area on Thursday,
however have values just under the 100 degree mark (heat advisory
.LONG TERM /FRIDAY THROUGH TUESDAY/...
With an upper ridge established across the CONUS, a hot and mainly
dry period is expected.
For Friday, a few afternoon thunderstorms may be triggered in an
unstable airmass by a short wave rounding the crest of the upper
ridge. Isolated thunderstorms may still occur Saturday under weaker
forcing but persistent instability.
On Sunday, greater short wave energy entering the northern plains is
forecast to develop a surface low that will drag cold front toward
the ILN area. A better chance for thunderstorms will exist in
increasing moisture and forcing ahead of the front. The chance for
convection will continue Monday as the front makes its way across
the area. Look for drier conditions Tuesday under weak high pressure
behind the front.
Temperatures will be hot. Highs in the 90s are forecast Friday
through Sunday, with heat indices reaching heat headline criteria
over 100. Somewhat cooler readings in the mid and upper 80s are
expected Monday and Tuesday due to modest cold advection.
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --Surface high pressure centered over the eastern Great Lakes this
morning will continue to extended southwest into the mid and upper
Ohio Valley through tonight. Some cirrus can be expected from time
to time in the northwest flow aloft along with some scattered
diurnal cumulus clouds. Winds will be calm or light easterly this
morning, light and variable this afternoon, then back to a light
east or southeast wind tonight.
OUTLOOK...Thunderstorms possible Sunday.
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