Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
701 PM EDT Monday Sep 26 2016
low pressure located north of Lake Superior will drift south across
the Great Lakes region towards Ohio through Wednesday. The low will
shift towards the mid-Atlantic coast on Thursday then retro-grade
west towards Ohio again to end the week.
Near term /until 6 am Tuesday morning/...
low pressure remains north of Lake Superior this afternoon but the
occluded cold front has now shifted east of the area. Showers lag
the front but will generally exit to the east through 6 PM with just
a chance of a few lingering showers along the northeast Lakeshore
later this evening. Nearly cloud free dry-slot is approaching across
Indiana and clouds will start to clear out of the western areas over
the next couple hours with temperatures making a run at a late day
high in Northwest Ohio. The clearing line will continue to move east
this evening as the broad dry slot moves overhead.
Dewpoints this afternoon across Illinois are already down into the
mid 30s. Although we will hold onto some wind tonight, temperatures
are forecast to drop into the lower to mid 40s.
Short term /6 am Tuesday morning through Thursday night/...
the upper level low is forecast to remain north of the area on
Tuesday. A dry airmass will be overhead with broad cyclonic flow.
Lake effect clouds will tend to shift north out over the lake with
time as low level winds back to southwesterly. Breezy conditions are
expected with a well mixed atmosphere and mostly sunny skies.
Temperatures will peak in the upper 60s after a cool morning.
The upper level low pivots southward on Tuesday night and Wednesday.
The vort Max moving east across the area on Wednesday with cold
pool aloft should kick off scattered to numerous showers with
even a few thunderstorms possible by Wednesday afternoon. At this
time the greatest coverage appears to be focused across northeast
Ohio during the afternoon, then lifts up across Lake Erie and
northwest Pennsylvania on Wednesday night. Raised pops to likely
in favored areas. With skies becoming mostly cloudy, temperatures
will only reach the lower 60s for most areas.
As the nearly vertically stacked systems drifts southeast on
Thursday, moisture begins to be pulled in from the Atlantic.
Scattered showers are expected to continue with diurnal enhancement,
even as the system starts to fill.
Long term /Friday through Monday/...
upper low will linger a while longer...beginning to pull away
Sunday. There is now some decent agreement on this scenario and
timing. Its presence will continue the cloudy weather and chances
for showers...although the chances will be diminishing each day with
the departure of the low. Temperatures will remain fairly steady
state...upper 60s for highs...reaching or topping 70 with peeks of
sun. Lows will continue to be in the lower 50s inland. All in all
Aviation /00z Tuesday through Saturday/...
the last of the lower clouds around eri should be east of the site
over the next hour. A few clouds starting to develop off of the Lake
May brush eri at times overnight/Tuesday morning. Some additional cu
will develop by midday Tue from daytime heating and the approach of
an upper low.
Gusts are settling down and most winds should stay under 12 knots
tonight then pick back up with daytime heating on Tuesday with gusts
of 25 to 30 knots.
Outlook...non-VFR possible for all terminals at times between
Wednesday and Saturday with upper low and showers lingering across
Small Craft Advisory conditions will continue on the lake through
the night and through Tuesday. Have extended the western Small Craft
Advisory until Tuesday evening with this issuance. Cold front is now
across the eastern end of the lake with cold air advecting in
overhead. The gradient remains tight and the stronger southwest flow
is expected to persist through Tuesday. The gradient relaxes
Wednesday as the low across the northern lakes drifts southward to
the Ohio Valley where it will remain nearly stationary through the
remainder of the week. This will generally provide lighter
winds...but with high pressure across the northern lakes and this
low wobbling south of the lake...the northeast wind may be strong
enough to generate small craft conditions again toward the end of
the work week.
Marine...Small Craft Advisory until 3 am EDT Wednesday for lez146>149.
Small Craft Advisory until 10 PM EDT Tuesday for lez142>145.