Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
925 am EDT Tuesday Sep 1 2015
high pressure will remain over the Ohio Valley through late
Wednesday. A backdoor cold front will move across the area early
Thursday. High pressure will build back over the region from the
northeast for the end of the week.
Near term /until 6 PM this evening/...
it remains pretty quiet this morning. Early morning is improving.
An upper low over Indiana will begin to move east toward southern
Ohio later today. This feature was active on Monday with showers
and thunderstorms underneath it. Expect some isolated showers and
storms to develop this afternoon...especially across the southern
end of the area. A lake breeze is expected to develop this
afternoon and then move inland. A few more storms could pop along
this boundary. Will go with a small 20 pop most of the area
although coverage will be more in the 5 to 10 percent range. 850
mb temperatures this afternoon will be similar to yesterday and see no
reason why high temperatures will be more than a degree or two from what
they were Monday. Only tweaks to sky coverage with this middle
morning update. Everything else right on track.
Short term /6 PM this evening through Friday night/...
a warm and humid airmass will remain over the region the entire
period. Expect any lingering precipitation to die out after sunset. The
new 00z models show the upper low passing just to the south of the
area tomorrow morning. Although more precipitation could develop as this
feature moves through...better chances will likely occur later in
the afternoon with the heating of the day. There will be no good
lifting mechanism at the surface so trying to figure where the
precipitation will be is a challenge again today. Do think the coverage
will be a little greater than today with best chances again across
inland areas. Slightly better chances for precipitation will occur on
Thursday as a back door cold front moves across the area. This
feature should provide just enough lift to initiate some scattered
storms. Will go with a 30 pop for now which should be more than
enough. Given the weak shear environment and moist atmosphere...any
storms that do develop could be slow movers and heavy rainer's.
By Friday a surface ridge from the high centered over New England
will be back in control. Slightly lower dewpoints are expected and
this should limit the precipitation threat.
Little change in temperatures aloft is expected this week so
persistence will be the way to go for temperatures. Expect most locations
to top out in the upper 80s for highs each day.
Long term /Saturday through Monday/...
Summer has finally arrived in the temperature department even though
we are into the month of September. The month of September begins
what is known as the meteorological fall.
Latest upper air forecasts indicate large amplified ridge will remain
persistent through the forecast period as a digging trough sets up
over the western United States. The strong upper level ridge in the
eastern half of the United States will keep the forecast area under
warm and muggy conditions for the foreseeable future.
Surface high pressure shifts to the East Coast through the period
and eventually sets up a conveyor belt of warm tropical air into the
forecast area by Monday and Tuesday. This will gradually increase
the threat for showers and thunderstorms by early next week. The
warm tropical air in place will help to destabilize the atmosphere
and I can expect some scattered showers and thunderstorms to develop
in the latter half of the forecast period. Otherwise...dominating
high pressure should keep things dry through much of the early part
of the extended periods.
Upper level ridge and surface high will produce some subsidence and
produce some warm to quite warm temperatures through the period.
With high dew points in place...expecting muggy conditions as well.
Bumped maximum and min temperatures up a few degrees due to the warm air
mass expected. Lake Shore areas will be a tad cooler than inland as
lake breezes develop.
Aviation /12z Tuesday through Saturday/...
scattered fog will dissipate this morning. Mainly high clouds
will spread into the area later this afternoon from widely
scattered convection well west of the area. Lake breeze will
develop this afternoon at Erie and Cleveland and dissipate at
sunset. Expecting more MVFR fog to develop later tonight again
Outlook...areas of non VFR in early morning fog. Isolated
thunderstorms may be around each afternoon/evening.
the influence of high pressure at the surface through much of the
forecast period will keep winds on the light side. There is the
possibility that winds could increase to around 10 to 15 knots over
the lake on Friday but will quickly diminish by Saturday morning and
return to light northeast. I am not expecting any small craft
advisories through the period.