Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
1012 PM EDT sun Jul 27 2014
a low near Detroit will move into New England through Monday then
drift north into eastern Canada by the middle of the week. High
pressure over the plains will spread up the Ohio Valley Thursday
then remain over the area into the weekend while upper level low
pressure is stalled over the region.
Near term /through Monday/...
the watch is gone. Had some glitches with the earlier extension but
hopefully thing are better now. Thanks for your patience. The
remaining warnings will expire shortly. Still expecting some
showers and a few storms overnight. Guidance coming in still
showing a fair amount of rain overnight and Monday along the east
Lakeshore. Elsewhere precipitation chances will finally to diminish after
midnight. Will make other changes as needed.
Short term /Monday night through Wednesday night/...
wrap rain showers are shown to affect the snowbelt area in the morning
becoming less numerous during the day as the short wave moves off to the
east taking the deeper moisture out of the area. A little thunder is
possible Monday but most places should just see rain showers so will
continue to not mention thunderstorms and rain. Temperatures will be noticeably cooler Monday
with highs mostly from the upper 60s to lower 70s.
Marginal lake effect conditions may allow a few rain showers to hang around
in the snowbelt Monday night into Tuesday morning. Later Tuesday...another
upper short wave drops into the area sharpening the main trough while
inducing a surface trough. There should be an overall pickup in scattered
rain showers later Tuesday into Tuesday night. Will make the threat for rain showers more
widespread across the County Warning Area and continue this through Wednesday as another of a
series of S/w's will dive into the main trough to keep it over the
area. Temperatures Tuesday and Wednesday will stay below normal
Long term /Thursday through Sunday/...
hard to get too specific in the long term portion of the forecast.
The trough aloft is prognosticated to deepen middle week and then linger. The
GFS has backed away from the previous solution of a long lasting
closed low but all of the models maintains an unseasonably deep
trough over the Great Lakes through next weekend and beyond. It will
be difficult to pick out a day with no chance of showers...perhaps
at night when convective processes diminish. Not going to go with
anything more than a "chance" of showers at this point given the
lack of details although at some point a trough or short wave will
rotate through and there will likely be more organized activity.
Temperatures will depend a lot on the amount of clouds and
showers but the pattern should bring temperatures at least a few
degrees below normal and perhaps as much as 5 or 6 degrees below
normal. Dewpoints will likely begin to creep up just a bit so the
air mass will loose its crisp and cool feeling and probably start to
get a damp and cool feeling.
Aviation /00z Monday through Friday/...
strongest storms near low/triple point now over Lake Erie...with
cold front now across Northwest Ohio. Low forecast to track east into
more unstable air in PA and New York state. As it does will drag the
cold front across the forecast area tonight. Behind the front
expect widespread MVFR with areas of IFR ceilings.
Outlook...non VFR in showers Tuesday through Friday.
the cold front should slide across Lake Erie tonight along with a
surface low. In the mean time we will have outflow boundaries from
thunderstorms over the western and Central Basin of the lake so the
wind will be variable and perhaps gusty at times this evening. Still
not sure exactly where the surface low will track...probably across
Eastern Lake Erie... so the wind shift may take until early Monday
on the east end of the Lake. Small craft advisories will be needed
Monday as the cold advection increases behind the cold front and it
will not be a good day for recreational boating. Waterspouts are
also possible Monday...perhaps into Tuesday... as the air aloft will
be unseasonably cool.
A large area of high pressure over the central portion of the
country will take all week to move east as the trough aloft deepens.
The end result will be a surface flow varying from southwest to
northwest much of the week. Each trough of low pressure that crosses
the lake can result in a period of higher winds and waves.
Ohio...Flash Flood Watch through Monday afternoon for ohz011>014-023-
PA...Flash Flood Watch through Monday afternoon for paz001>003.