Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
943 am EDT Friday Aug 22 2014
disturbances in northwest flow aloft will interact with a very
warm and moist airmass to produce showers and thunderstorms at
times over the next few days.
Near term /until 6 PM this evening/...
mesoscale convective system continues in its weakening phase. Echoes are slowly weakening
with little in the way of lightning left. In addition southward
progress has halted. At this point expect it to continue to decay
in place. Appears that additional rainfall will not be excessive.
But with a good deal of rain from earlier will continue to monitor
east central Indiana and west central Ohio.
Question then becomes what will evolve through the afternoon.
Expect that recovery of the atmosphere will be limited where mesoscale convective system
impacted this morning. There is an outflow boundary moving into
the far southern counties and where this sets up could be a prime
focus for afternoon convection. At this point will keep higher
chance probability of precipitation where precipitation did not fall and there is a better
chance of destabilization this afternoon. So expect northern
Kentucky and far southern Ohio along with central Ohio to have a
higher chance of afternoon storms. Will continue Flash Flood
Watch for now and further evaluate the threat for heavy rainfall
in that area as the day progresses.
Opted to bump down highs except across far southern counties where
modification from mesoscale convective system will be limited at most.
Short term /6 PM this evening through Sunday/...
storms expected to be ongoing this evening as complex of thunderstorms
drops southeast through ilns forecast area around the NE periphery of middle/upper level
ridge over the MS valley. The models are in general agreement in
sharpening up the ridge. This should allow the precipitation to push south
of ilns forecast area tonight. In muggy airmass low temperatures to range
from the upper 60s NE to the lower 70s SW.
The upper level ridge continue to build a little east Saturday.
Additional convective development will be possible again Saturday
under the upper ridge. Southwestern portions of the forecast area will have the
better chances. Any convection that develops Saturday is expected
to diminish Saturday evening with the loss of heating.
Highs in the upper 80s to lower 90s with heat indices again in the
southwest near 100 on Saturday.
Upper level flow continues to amplify Sunday with the ridge
building northeast into the Great Lakes region. With iln/S area
still on the periphery of this high...a low probability of precipitation for thunderstorms
will continue Sunday. Will allow for a slight chance of
thunderstorms on Sunday...mainly during afternoon/early evening
hours. Highs in the upper 80s to around 90 with heat indices
approaching 100 again in the SW. Therefore...will continue to mention
heat for Sunday in severe weather potential statement.
Long term /Sunday night through Thursday/...
as the upper level ridge builds across our area Monday...better
instabilities will work more east northeastward across our area
too. However...with warming in the middle levels and a continued lack
of forcing...think any thunderstorm activity will remain isolated
enough to leave mention out of the forecast. The upper level ridge
will slowly begin to flatten out through middle to late in the week
as short wave energy pushes across the Great Lakes. This will
eventually help drive a cold front down toward our area late in
the work week. This will lead to an increasing chance of showers
and thunderstorms from the northwest Wednesday into Thursday.
Temperatures will remain on the warm side through middle week...with
highs generally in the upper 80s to near 90...before a possible cool
down with the approach of the front on Thursday.
Aviation /14z Friday through Tuesday/...
short wave energy on a northwest flow aloft carrying plentiful
moisture along a surface boundary is producing widespread
convection. Numerous showers and a few thunderstorms will
continue into late morning. After a lull during early
afternoon behind the initial short wave...more convection is
likely to develop later this afternoon and this evening.
Conditions may improve tonight when models show surface boundary
moving south of the Ohio River.
MVFR conditions will be typical with showers and thunderstorms in
this humid and unsettled regime. Could see some strong wind gusts
late in the period if intense convection impacts taf sites.
Outlook...thunderstorms possible through Saturday.
Ohio...Flash Flood Watch through this evening for ohz026-034-035-
In...Flash Flood Watch through this evening for inz050-058-059-066.