Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
956 PM EST Sat Nov 22 2014
mainly cloudy skies with embedded showers from time to time
are in store for tonight in a relatively moist and mild southwesterly
flow. For Sunday and Sunday night...deepening low pressure will
pull a large swath of moisture northward...resulting in widespread
rain showers. More showers and windy conditions will accompany a
cold front on Monday.
Near term /until 6 am Sunday morning/...
latest 00z NAM-WRF...hrrr and rap indicate that area of showers
over east central Illinois/west central Indiana will expand and
pivot northeast overnight. This precipitation is in response to an
embedded shortwave and low level jet within a moist southwest plume.
Have increased probability of precipitation to likely for northwestern zones after
midnight with probability of precipitation rapidly decreasing as one GOES toward the Ohio
River. Skies will be mainly cloudy for most locations.
Temperatures have already fallen off considerably in south central
Ohio and northeast Kentucky while it remains mild elsewhere. We
should see a gradual decrease in temperatures northern/western
zones overnight with some recovery expected southeast as clouds
thicken and perhaps a little wind picks up.
Short term /6 am Sunday morning through Monday night/...
an elongated area of low pressure will be strengthening to the
west on Sunday. Moisture arriving on an increasing southerly flow
will overspread the area...bringing rain showers to all locations
by Sunday evening. The showers are likely to continue Sunday night
and Monday as the low moves north and deepens over the Great
Lakes...while dragging a strong cold front from the west. Looks
like the area could receive around an inch of rainfall on average
by Monday afternoon. Showers should end Monday night as the system
Another problem will involve strong winds...especially on Monday in
the vicinity of the cold front. Current indications are that
numerous gusts of 35 to 45 miles per hour are probable. If conditions are
as suggested by the windier mav guidance...then a Wind Advisory
may be needed.
Warm advection will bring highs into the middle 50s to around 60 on
Sunday. Highs on Monday should stay in the 50s with colder air
filtering in from the west Monday afternoon.
Long term /Tuesday through Saturday/...
below normal heights with mean trough over the nations middle section to
start the long term forecast period. Precipitation should stay north
of iln/S forecast area with surface high pressure building into the Ohio Valley
Tuesday. Temperatures will be close to 15 degrees below normal...
with highs from the lower 30s north to the lower 40s southeast.
Iln/S forecast area between systems on Wednesday as surface high pressure shifts east on
Wednesday. Below normal temperatures to continue with highs ranging from
the middle 30s north to the lower 40s south.
Clipper type system to drop southeast through the Great Lakes with associated
cold front sweeping east through iln/S forecast area early Thursday. Will bring
snow in Wednesday night and continue into Thursday. Some precipitation mix with be
possible across the south. Have leaned toward the colder European model (ecmwf) solution
and have limited any mix to the southeast. Best probability of precipitation across the north closer
to the surface wave. Early highs on Thursday to range from the lower 30s
northwest to near 40 southeast.
In northwest flow and cold air advection some lingering snow showers possible Thursday
night. Surface high pressure to build in on Friday providing continued cold
temperatures and dry conditions. Highs on Friday to range from the
lower 30s northwest to the upper 30s southeast.
Surface high pressure to build across the region as middle level flow backs
westerly. A quick return low level flow to develop on the back side
of the retreating high. Will hold off on any warm air advection precipitation until Saturday
Aviation /03z Sunday through Thursday/...
an embedded disturbance within a moist southwest flow aloft...along
with a low level jet...will team up to bring some more showers to
the taf sites overnight with the highest probability occurring at
the northern taf sites of kday...kcmh...and klck. Ceilings should
remain VFR with perhaps some brief MVFR visibilities with showers.
On Sunday...a decent upper level disturbance will rotate northward
from the lower Gulf coasts states to the Ohio Valley by Sunday
night. This feature will eventually become absorbed by stronger
upper level energy to the west by Monday morning. Increasing moist
ascent with a substantial low level jet along with increasing
divergence aloft will spread widespread showers into the area from
south to north between 18z and 00z. MVFR conditions can be
expected at the onset...followed by deteriorating ceilings and
visibilities into the IFR category due to locally moderate/heavy
showers. Winds will increase as well and will back with time from
a southerly direction to a southeast direction as low pressure
deepens over the middle Mississippi Valley and a warm front approaches
from the south. Showery weather...but not as heavy...will continue
later into Sunday night ahead of a strong cold front. Ceilings
should remain in the IFR category.
Outlook...MVFR/IFR ceilings and MVFR visibilities to continue into
Monday as a strong cold front moves through the region. Gusty
southwest winds around 35 knots likely Monday into Monday night.
MVFR ceilings possible Monday night into Tuesday. MVFR/IFR
conditions possible Thursday.