Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
626 PM EDT Monday Aug 3 2015
cold front from eastern lower Michigan into northern Indiana moving east and
is forecast to be from near Erie PA to northern Kentucky by 00z this evening.
A second cold front will drop across the area Tuesday as upper
low pressure lingers over the Great Lakes. High pressure will
briefly build back into the Ohio Valley Tuesday night into
Near term /until 6 am Tuesday morning/...
storms over Lake Erie continue to hold together and have added a
precipitation mention to northwest PA for this evening. Expect this activity to
diminish after sunset. No other changes.
Previous...front near a line from The Thumb of Michigan south-southwest to near
Fort Wayne this afternoon and can be see in dewpoints which drop
into the 50s behind the boundary. Satellite shows a good
convective cumulus field ahead of the front across Northern Ohio and northwestern PA
with mixed layer convective available potential energy across the western 2/3ds of the area now
are between 1000 and 1500 j/kg. Radar shows showers developing
offshore Erie PA as well as in Stark County and points southeast. Deeper
instability along with low level convergence has helped convective
development near kmie. Expecting further development to its south
and east with a general east-southeast motion. Will continue with
chance probability of precipitation through the balance of the afternoon roughly east of a
kmnn- kcle line. Probability of precipitation will be lowered each hour through about 04z
following diurnal trends. After midnight however models increase
moisture across far northestern Ohio and northwestern PA associated with upper
low rotating through the Great Lakes. Will need to bring a chance
of showers to northwestern PA and Ashtabula County to cover threat.
Overnight lows from 55 to near 60 look fine given the cool down in
temperatures across the area.
Short term /6 am Tuesday morning through Thursday night/...
Tuesday and Tuesday night will need to contend with high relative humidity as
well as perturbations wrapping around the closed upper low over
the Great Lakes. Enough weak high pressure and dry air to keep
skies pc west and south of roughly a klpr to kyng line but across
northestern Ohio and northwestern PA believe enough moisture gets in to go with
mostly cloudy through at least the afternoon and evening. Will
also keep chance probability of precipitation through the day and into the night far
northeast. Wednesday high pressure will affect the area through
the day as the upper low pulls east. By evening however moisture
will be increasing from the southwest. Models Show Low pressure
developing in the Central Plains. Quite a bit of difference in the
the models for Wednesday night with the GFS the furthest north
with the high relative humidity vs the NAM/ECMWF. Will follow more of a NAM/European model (ecmwf)
blend bringing the moisture/probability of precipitation into the area from the west-southwest after
midnight Wednesday night. By Thursday morning...will have low
pressure in southern Illinois with chance probability of precipitation into the western counties.
Thursday differences continue with the European model (ecmwf) favoring precipitation
mostly south of the area while the NAM is further north across
much of Northern Ohio as well as the south. Will go with chance probability of precipitation.
Instability limited so will have only a slight chance for thunder.
Long term /Friday through Monday/...
a trough aloft will maintain slightly below normal temperatures
through the weekend. The area of low pressure moving through the
Ohio Valley on Thursday will start to pull away to the east on
Friday. Will continue to carry a low chance of showers...mainly
southern and eastern areas as some moisture remains. The airmass
continues to dry out on Friday night and Saturday with high pressure
building in from the northwest. The GFS is a little cooler on
Saturday which could result in some clouds off of Lake Erie
during the morning...but expect it will clear through the day. If
cloud cover ends up being more than expected then temperatures may
need to be lowered over the weekend.
Aviation /18z Monday through Saturday/...
a weak front draped across the area will shift east through
03z. Scattered-broken clouds in the 2-3k range will affect
fdy/mfd/cak/yng/eri over the next couple hours before scattering
and lifting. A chance of thunderstorms remains...mainly at
mfd/cak/yng but chances are low enough it is not included in the
forecast. Will update as needed if convection develops but better
chances are better south of the area. Otherwise westerly wind
will be breezy at times this afternoon with gusts near 20 knots.
Winds will decrease towards 00z and back to southwesterly most
areas overnight as high pressure builds to the south. Winds will
increase to 10-15 knots again by 16z Tuesday.
Outlook...non VFR weather possible late Wednesday through Friday.
winds are starting to decrease on Lake Erie but waves will remain
high on the east end of the lake for a few more hours. Have extended
the Small Craft Advisory and beach hazards statement until 8 PM from
Geneva-On-The-Lake to Ripley. Conditions may still be a little
choppy with 2 to 4 foot waves off of Lake County but conditions
should start to improve.
Winds will remain out of the west northwest on Tuesday then shift to
northeast by Wednesday. An area of low pressure will track through
the Ohio Valley on Thursday...maintaining a northeast wind. There is
some disagreement with models on how strong this feature may be and
winds may need to be adjusted.
Ohio...beach hazards statement until 8 PM EDT this evening for ohz089.
PA...beach hazards statement until 8 PM EDT this evening for paz001.
Marine...Small Craft Advisory until 8 PM EDT this evening for lez148-