Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KILN 180625
Area Forecast Discussion
National Weather Service Wilmington OH
225 AM EDT WED MAY 18 2016
Surface low pressure south of the Ohio Valley will interact with
upper low pressure in the lower Great Lakes, bringing rain
showers tonight. High pressure and a dry airmass will travel
across the Great Lakes and Ohio Valley on Wednesday and Thursday.
Another area of low pressure is forecast to bring more showers for
Friday and Saturday.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Broad area of showers associated with mid level shortwave energy
will continue to progress ENE across the forecast area over the
next several hours. Will see this band eventually exit the eastern
portion of forecast area shortly after daybreak Wednesday. Meanwhile
an axis of weak low level convergence over northern Ohio and
Indiana this evening continues to trigger a few showers
progressing ESE. This activity seems to have started waning, as
recent HRRR runs have suggested. Tweaked temperatures downward a
couple degrees mainly across the far north where clouds will
decrease the earliest as drier air encroaches by morning.
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
The H7 low will exit east of the region in the morning and
significantly dry air will overcome any mid-level forcing
associated with the H5 vort maxima moving through as the shortwave
trough at this level crosses northern ohio and Lake Erie early on
Wednesday. Some lingering low level moisture could eke out a
sprinkle with peak daytime heating in the afternoon, but the only
concession made on this forecast was to have the non-zero pops of
14% and not clear out the sky cover until late in the day.
Clearing and a better warming period is in the forecast beyond
Wednesday night but will still be below climatological normals in
the lower 70s. Expect nighttime lows to drop into the 40s with the
dry and clear airmass in store for Wed and Thurs nights. Abundant
sunshine may necessitate an increase in high temperatures on
Thursday that will also be combating with cold advection on
The next system approaching from the southwest may impact our far
southern CWA in northern Kentucky by daybreak Friday with some
shower activity on the increase.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Friday morning high pressure over the Great Lakes will slowly be
pulling east with upper level low pressure over Maine and the
Pacific Northwest. At the same time an upper level disturbance
over the midwest will be pulling east towards Ohio. Both the GFS
and Euro are in pretty good agreement bringing the system over the
area Friday afternoon. This is a tad slower in timing than
previous model runs so have made minor adjustments to PoPs to
account for this. PWATS quickly rise ahead of the shortwave to
just above 1.00" but low level dry air remains. Not until Friday
evening does the entire sounding eventually saturate. Lift from
the shortwave should be more than sufficient with pockets of PVA
moving overhead (further supported by GFS omega values). For now
have kept PoPs at likely due to timing uncertainty, but given lift
and eventual saturation of forecast soundings categorical PoPs
will probably be needed.
On Saturday a stronger shortwave will dive south out of Wisconsin
merging with the weaker more southern shortwave. This will allow a
surface low to form near the Carolinas and track northeast. PWATs do
slowly fall on Saturday but the proximity of the low and some
remaining instability will keep the chance of precipitation around.
Finally on Sunday the area will begin to dry out as the shortwave
deepens just east of the area helping to bring in dry air (PWATS
falling to just above 0.5") across area.
For Monday through Wednesday the Euro and GFS diverge slightly with
the GFS not being as progressive with an upper level low that forms
just east of the forecast area. The Euro is slightly more
progressive. Either way the chance of rain looks low through the
remainder of the long term period (Tuesday) as ridging and dry air
remain in place.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --A shortwave will track thru the region overnight as an upper
level low pivoting thru the great lakes. VFR conditions with these
showers will drop down temporarily to MVFR for a period toward
Favorable forcing will end with the shortwave moving thru and the
rain will end from west to east late tonight. MVFR cigs will
linger into the early morning and then improve as surface high
pressure begins to build in from the northwest today. Cigs will
improve to VFR by aftn and then scattering out by evening.
Winds will generally be light out of the northeast tonight and
then from the ne around 10 kts durg the daylight hours.
OUTLOOK...MVFR ceilings and visibilities possible Friday and Saturday.
-- End Changed Discussion --