Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
419 am EDT sun Jul 31 2016
a broad area of low pressure in place across Northern Ohio will
slowly shift east into Pennsylvania tonight. High pressure will
build over the Great Lakes region on Monday and shift east to New
England by Wednesday.
Near term /until 6 PM this evening/...
broad upper level trough is located over the central Great Lakes
with a weak area of low pressure at the surface across Northern Ohio
and Lake Erie. Showers and thunderstorms have been forming over the
lake for the last several hours with low level convergence focused
over the lake and shortwave energy aloft. These will likely continue
into the morning before starting to weaken. Otherwise, a stratus
deck has been expanding across Northwest Ohio where skies have
cleared out. Expect this deck to expand further east, especially
into areas that received a lot of rain yesterday from Bellevue
southeast towards Ashland and Wooster. Diurnal heating will cause
clouds to bubble up before gradually starting to break up.
One more piece of shortwave energy is expected to slide northeast
across the area this afternoon and scattered showers and
thunderstorms will develop once again. The better coverage of storms
should be focused in northeast Ohio where southerly flow will remain
ahead of the low before winds eventually come around to the
northwest on the back side in the evening. Storm motion will be
slow for another day and thunderstorms will produce locally heavy
rainfall. Localized flooding will be possible, especially if
thunderstorms train over areas that received heavy rain yesterday.
Much drier mid-level air starts to spread into western areas this
afternoon, limiting the coverage of thunderstorms across Northwest
Ohio. Nudged temperatures up a degree or so with highs ranging
from the upper 70s in PA to lower 80s in Ohio.
Short term /6 PM this evening through Wednesday night/...
convection will dwindle this evening although storms could fire
across the eastern half of Lake Erie again overnight. Will carry a
low chance pop in northeast Ohio/northwest PA with a few storms
possibly moving in off the Lake.
A drying trend gets underway on Monday as high pressure builds
overhead. Aside from a slight chance of showers in the extreme east
early Monday, dry conditions will return and persist through
Tuesday. The trough aloft will shift to New England and eventually
offshore with heights rebounding aloft. Temperatures will warm
again with highs in the mid and possibly upper 80s by mid- week.
Models have been hinting for several days that a cluster of
thunderstorms will develop across the upper Midwest on Tuesday and
slide southeast across Lake Michigan into Wednesday. A lot of
uncertainty with timing or track of this feature but did add some
clouds and even a low pop to the forecast on Wednesday as this
feature has maintained some run to run continuity.
Long term /Thursday through Saturday/...
warming temperatures on the way as upper level ridge builds east
into the forecast area. The surface high pressure that is expected
to move east across the area over the next couple days will move
east of the region and develop a return southerly flow once again.
The warm air advection will force moisture north out of the Gulf of
Mexico region into the local area. This will prime the atmosphere
with moisture and instability by Friday. A cold front is progged to
move east across the region and will provide the lifting mechanism
for the development for thunderstorms. The potential for severe
thunderstorms hinges on the timing of the cold front.
As mentioned, warm air advection will take place ahead of the cold
front and we should see temperatures gradually increasing with time
each day. Mid level temperatures do not support highs climbing into
the 90s at this time. Plus, with all of the moisture expected,
potential exists for more clouds that in the past really warm days.
So will keep 80s for highs for now and lows around 70 or upper 60s.
Aviation /06z Sunday through Thursday/...
big question is when and where will the showers and thunderstorms
develop? Activity is widely scattered and when it develops it
pretty much collapses where it began or moves very little. Winds
aloft are extremely light. Expecting possibility for low clouds
and some lower visibilities to develop over the next few hours
across the forecast area. Some improvement will take place across
the area during the day but still expecting VFR ceilings to hang
around. Gradual clearing will take place later in the evening as
storm system pulls out to the east. Generally light winds through
Outlook...non-VFR possible Monday morning.
no headlines expected over the next 5 days on the lake. Winds are
expected to be pretty light on the water keeping waves under 2 feet
through the period. Showers and thunderstorms as a result of
convergence down The Spine of the lake will continue this morning
but will become more scattered through the day.