Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KILN 201459
Area Forecast Discussion
National Weather Service Wilmington OH
1059 AM EDT FRI MAY 20 2016
A low pressure system will lift out the Tennessee Valley and into
the Upper Ohio Valley through tonight. This will bring widespread
showers to the region later this afternoon and overnight.
Scattered showers will linger into Saturday as the low pressure
system moves off to the east.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Previous forecast appears to have the situation well in hand, so
only a few minor tweaks. Mesoscale models continue to show an area
of convection will lift up out of western and central KY, into ne
KY and srn OH late this afternoon into this evening. Models are
bringing some heavy QPF with this convection. While some heavy
rains are expected, will hold off on a FFA, but will monitor the
situation and see if one is needed later.
Bumped temperatures down a degree or so with the pcpn coming in.
-- End Changed Discussion --
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
The surface low will be located somewhere across southern Ohio
Saturday morning and is forecast to weaken as it drifts slowly off
to the east southeast through the day. This will result in
scattered lingering rain showers through the morning, before
beginning to taper off from the west through the afternoon as
some drier air tries to work in. Expect mainly dry conditions
Saturday night, but a mid level short wave will drop quickly down
across eastern Ohio on Sunday, resulting in the possibility of a
few showers across our east. Expect highs on Saturday mainly in
the upper 60s, warming into the lower 70s for Sunday.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Sharp ridging over the Mississippi Valley region will move east
and envelop the Ohio Valley by Monday morning, providing a period
of dry weather and warming temperatures. Going into the new week,
the pattern appears more typical of late spring -- with warmer
southerly flow at the surface, and chances for precipitation as
occasional waves move along the generally-westerly mid-level flow.
Recent model runs have been slightly faster with the onset of the
pattern change, and now suggest that precipitation chances could
begin as early as Tuesday evening (in a regime of strong
southwesterly 925mb-850mb theta-e advection). Pseudo-zonal flow
beyond this time range will likely support occasional chances for
showers and storms during the rest of the week, but timing the
small-scale features out will be critical for specifics on this
part of the forecast as it gets closer to the current time.
Temperatures are expected to rise above normal through the long term
forecast period, especially beginning on Tuesday, when the southerly
near-surface flow becomes established. The occasional chances for
precipitation during the middle of the week will keep these forecast
numbers on the conservative side (upper 70s to around 80) for now,
but these could need to be increased slightly on any given day if a
brief dry / sunny period eventually becomes more certain to occur.
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
All taf sites vfr this morning as widespread cirrus has moved into
the area ahead of the next system. There are some light returns
on the radar off to the southwest, but the atmosphere is
currently relatively dry though (PWATs around 0.6") so these
returns are likely evaporating before hitting the ground.
By later this afternoon the atmosphere will quickly saturate as
the upper level low approaches (PWATs on the GFS and NAM around
1.4"). The high res ARW, NMM, and RAP are in good agreement
bringing rain into CVG/LUK between 18 and 21 Z while the latest
run of the HRRR is about 3 hrs faster. Have followed the ARW,
NMM, and RAP solutions when constructing the TAFs. The latest run
of the NAM is now showing more instability than the previous run,
but looks to ambitious in destabilizing the atmosphere. The GFS
shows very little instability. Have kept the mention of thunder
out of the TAFs as the GFS appears the more likely solution.
For the most part this afternoon cigs will stay VFR until the
surface low arrives later this evening. As the surface low moves
overhead cigs will fall very quickly to IFR and then LIFR. GFS and
NAM forecast soundings are in very good agreement with this along
with SREF prob cig heights. Cigs will the likely stay down into
Saturday morning as TAF sites remain in close proximity to the
OUTLOOK...Thunderstorms possible Saturday.