Area forecast discussion
National Weather Service Wilmington Ohio
315 PM EDT Sat may 18 2013
Synopsis...
a warm front lifting north of our area will leave US in a warm and
moist airmass through the start of the week. A weak upper level
disturbance will bring a chance for showers and thunderstorms
through the weekend. Weak ridging will build across the region on
Monday...bringing to the area a brief break from precipitation.
&&
Near term /through tonight/...
dewpoint boundary in observation Colorado-located with weak echoes on radar are
indicating that a frontal boundary that had been across our area
for the past couple of days is now beginning to lift northward.
This boundary will likely be north of our area entirely later this
evening. A weak upper level disturbance crossing northwestward
across the Ohio Valley will provide sufficient lift to allow for
showers and thunderstorms develop mainly across the south where
more sunshine...and therefore more instability is located.
Once diurnal heating is lost this evening...activity will quickly
diminish into lighter showers before completely dissipating late
tonight. Expecting mostly cloudy skies tonight. However some breaks
should occur. If enough breaks do develop where precipitation
occurs today...cannot rule out fog development. Kept the forecast
for fog out of the grids for now to to the uncertainty with
regards to cloud cover. Went about a degree cooler than a
consensus blend for tonight's lows as there appears to have been a
slight warm bias in the model forecasts for the past couple of days.
&&
Short term /Sunday through Monday/...
a warm front lifting north of our area will leave US in a warm and
moist airmass through the start of the week. A weak upper level
disturbance will bring a chance for showers and thunderstorms
through the weekend. Weak ridging will build across the region on
Monday...bringing to the area a brief break from precipitation.
&&
Near term /through tonight/...
dewpoint boundary in observation Colorado-located with weak echoes on radar are
indicating that a frontal boundary that had been across our area
for the past couple of days is now beginning to lift northward.
This boundary will likely be north of our area entirely later this
evening. A weak upper level disturbance crossing northwestward
across the Ohio Valley will provide sufficient lift to allow for
showers and thunderstorms develop mainly across the south where
more sunshine...and therefore more instability is located.
Once diurnal heating is lost this evening...activity will quickly
diminish into lighter showers before completely dissipating late
tonight. Expecting mostly cloudy skies tonight. However some breaks
should occur. If enough breaks do develop where precipitation
occurs today...cannot rule out fog development. Kept the forecast
for fog out of the grids for now to to the uncertainty with
regards to cloud cover. Went about a degree cooler than a
consensus blend for tonight's lows as there appears to have been a
slight warm bias in the model forecasts for the past couple of days.
&&
Short term /Sunday through Monday/...
favored a blend of the 12z GFS and Canadian global model for the
short term. The weak upper level disturbance will slide east of
our area on Sunday as middle level ridging builds east across our
area. Lingering lift provided by the upper low and increasing
instability Sunday afternoon is expected to produce scattered
showers and thunderstorms...mainly across the eastern zones.
Across the west...a building cap associated with the middle level
ridge and warming temperatures aloft will limit convection from
occurring.
Temperatures on Sunday will likely be lowest...in the upper
70s/lowers 80s...in the east where greater cloud cover will be
located and precipitation chances are higher. In the west...partly
cloudy skies with increasing temperatures aloft should help
temperatures rise into the middle 80s.
Temperatures aloft will continue to rise Monday night as middle level
ridging continues to amplify across the Ohio Valley in response to
a storm system developing on the Lee side of The Rockies.
Subsidence and capping under this ridge should prevent any
precipitation from occurring from late Sunday night through Monday.
Currently forecasting partly cloudy skies with well above normal
temperatures both Sunday night and Monday. On Monday...if skies do
remain mostly clear...with 850 hpa temperatures expected to rise
into the upper teens under southwesterly flow...temperatures could
reach the upper 80s in most locations. Cannot rule out a few spots
reaching the 90 degree mark if the 12z CMC/GFS scenario does play
out.
&&
Long term /Monday night through Saturday/...
middle level ridging across the eastern United States will begin to
break down through middle week. This will allow a series of short waves
riding up the back side of the ridge to have an increasing affect on
our area Tuesday into Wednesday. This will lead to an increasing
chance of thunderstorms through middle week...with the highest probability of precipitation
across our northwest...closer to the upper level forcing. 850 temperatures
on Tuesday will still be in the 16 to 18 degree celsius range so
expect highs generally in the middle 80s...although will go a little
cooler across the northwest where there will be a better chance of
precipitation. Heights will begin to fall Tuesday night into Wednesday
leading to highs on Wednesday in the upper 70s to lower 80s.
A middle/upper level trough will progress slowly east across the region
through the end of the week. An associated cold front will slowly
drop down through our area on Thursday. This will keep a chance
of thunderstorms going through the day on Thursday...tapering off to
showers behind the front Thursday night. A few showers could linger
into Friday before the upper level through axis pivots east. This
will also usher in a cooler airmass heading into the weekend with
highs in the upper 60s to lower 70s for Friday and Saturday.
&&
Aviation /18z Saturday through Thursday/...
area is under a moist easterly low level flow...supported by a weak
upper trough and cold pool crossing the area this afternoon. This
pattern will result in scattered showers... especially at
southern sites this afternoon as instability increases due to
daytime heating. Kept thunderstorms out of the forecast because
of their isolated nature. Above average humidity will allow br
with MVFR visibilities to form today with some of the
showers...and again tonight after showers and clouds decrease in a
regime of calm winds and moist conditions near the ground. Since
showers may develop again Sunday afternoon...included vcsh near
the end of the 30 hour cvg taf.
&&
Iln watches/warnings/advisories...
Ohio...none.
Kentucky...none.
In...none.
&&
$$
Synopsis...latto
near term...latto
short term...latto
long term...jgl
aviation...coniglio
