Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
205 PM EDT Sat Aug 30 2014
a series of upper level disturbances will move east across the
region through early next week...resulting in a continued chance
Near term /until 6 PM this evening/...
rain showers are edging into extreme western portions of the forecast area.
Instability is limited and there has not been a lot of lightning.
These showers and isolated storms will move into northwest portions of
the forecast area through early afternoon. Another round of showers and
storms will push into southern portions of the forecast area later today.
Expect temperatures to continue to jump quickly for the next
couple of hours however then expect the warming to slow down as
additional clouds move into the region. A few wind gusts have
already been seen around the forecast area. Expect additional wind gusts
around 20 miles per hour to develop for the afternoon and early evening hours.
Short term /6 PM this evening through Monday/...
the middle/upper level trough moving out of the middle Mississippi
Valley will weaken as it progresses east across the upper Ohio
Valley tonight through Sunday. As it does...the flow aloft will
transition into more of a zonal flow pattern with a series of upper
level short waves moving east across our area tonight through
Sunday. This will lead to an increasing chance of showers and some thunderstorms
tonight...especially across southern and southeastern portions of
our forecast area...where a developing 925-850 jet will nose in from the
south later tonight. Fairly high precipitation chances will continue into
Sunday as moist southwesterly low level flow persists. It looks
like we may get into a bit of a lull Sunday night into Monday
morning as better short wave energy pushes off to the east. As we
destabilize through the day on Monday...some isolated thunderstorm
activity will again be possible...especially during the afternoon
hours. Clouds and precipitation should help keep highs generally down in
the lower 80s for Sunday...with temperatures then warming back up
into the middle 80s for Monday.
Long term /Monday night through Friday/...
have used a blend of the 00z European model (ecmwf) and the 12z European model (ecmwf) for the long
term forecast. Each model run was similar to each other with timing
and placement of upcoming synoptic systems. Also..the GFS seem too
fast in pushing a warm front back northward middle week based on middle to
upper level flow.
For Monday night into Tuesday night...a cold front will slowly
sag southeast into the region...eventually stalling out somewhere
over the central or southern County warning forecast area by Wednesday morning. Best upper level
dynamics pass by to the north on Tuesday afternoon and evening.
However...enough heating and frontal convergence call for at least
40 to 50 probability of precipitation.
On Wednesday...frontal boundary as mentioned is expected to stall
over the area while middle level flow begins to buckle a little. Will
continue with a low chance for showers/storms...mainly central and southern
sections through Wednesday afternoon/early evening.
Looks like middle level ridge to our south will try to build northward
Thursday into Friday ahead out ahead of the next shortwave and cold front
to move into the region by the weekend. Have kept Thursday dry in
the moist return flow although there is a very small chance for a
pop up shower or storm. Have gone with 20 and 30 probability of precipitation on Friday
ahead of the approaching cold front.
Temperatures through the period will be near or above seasonal
normals for early September.
Aviation /18z Saturday through Thursday/...
an area of rain showers will move close to kday at the beginning
of the taf period. Handled these showers with a vcsh mention. Some
wind gusts around 18 to 20 knots will be possible through the
early evening hours.
Shower activity will become more widespread across the area later
this afternoon into this evening. There is a little bit better
instability during the late afternoon and into the early evening
hours and therefore have a thunderstorms in the vicinity mention in at the tafs during this
time. Although some isolated thunderstorms cannot be ruled out
believe that thunder chances will be minimal. Due to this have
left thunder out of the tafs overnight and into the morning hours
on Sunday. Rain showers will be widespread across the area taf
sites tonight however.
Ceilings and visibilities will gradually become MVFR tonight. IFR ceilings will be
possible for a time late in the overnight and into the early
daytime hours at kday and Kiln. IFR visibilities will also be briefly
possible at times with some of the heavier downpours tonight at
the taf sites.
There will be a decrease in the shower activity Sunday morning
however kept a vcsh mention in the tafs. Additional showers and
thunderstorms will be possible by the end of the taf period. Ceilings
and visibilities will gradually improve during the day on Sunday.
Outlook...thunderstorms possible through Tuesday.