Area Forecast Discussion
Issued by NWS Cleveland, OH

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641
FXUS61 KCLE 230519
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
119 AM EDT Wed Aug 23 2017

.SYNOPSIS...
A cold front will move across the area this evening bringing in
a cooler airmass that will stick around for several days. A
couple of troughs will sink south across the area, one on
Wednesday night and the other Thursday night. High pressure
from south- central Canada will overspread the Great Lakes
region Friday and through the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
Update...The cold front has made its way across the area with a
secondary, weak boundary located along the Lake Erie shoreline.
Aside from a couple lingering showers across northwest
Pennsylvania over the next couple hours, dry conditions are
expected through the night. No changes made to the previous
update.

Relevant Previous Discussion...
Dewpoints under 60 degrees will not arrive until after
midnight. Secondary boundary upstream across central lower MI
with a narrow line of showers marks the more dramatic drop in
dewpoints. After the cold front skies will clear. Lows will make
it into the 50s for most locations.

There will be enough moisture available Wednesday to get cumulus
development and partly cloudy skies. Trough will be nearing by
late in the afternoon so have a few showers in the forecast
across the snowbelt, expanding those across more of north-
central Ohio Wednesday evening. These will be lake enhanced as
by 06Z Thursday will be around +8C. Lower/mid 70s for highs
Wednesday and 50s Wednesday night.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
The short term begins Thursday with the models showing upper low
over eastern Canada with a rather sharp upper trough dropping
southeast across the central lakes toward the area. This trough will
swing southeast across the area during the day with high pressure
and drier air building in for Friday and then continuing through
Saturday. For Thursday main concern will be development of showers
with the cool air aloft across the region.  Best chance will
be over and southeast of the lake where water temps remain in the
low to mid 70s. Bufkit forecast soundings show moderate instability
to the lake and an updraft depth of over 20kft. At this time will
have low chance pops east of a MFD to CLE line but if synoptic
moisture is better than forecast pops may need to be raised. Will
continue with slight chance pops closer to the lakeshore Thursday
night from CLE east. Otherwise dry. Temps on the cool side.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure will remain the dominant weather feature as we head
into the extended portion of the forecast. Surface high pressure
over Ontario and Quebec will drift to the New England states by
Tuesday. The airmass will be dry during this time until moisture
starts to sneak back north on the back side of the high during the
Monday/Tuesday time frame. Best chance for a shower on Monday or
Tuesday is focused towards NW Ohio ahead of an upper trough dropping
into the Midwest but will limit pops to 20 percent for now. The
Canadian is an outlier early next week and is much more aggressive
in lifting a wave up from the Gulf Coast that would bring higher
chances of rain. Will keep an eye on this potential but not
incorporate into the forecast for now. Temperatures will be just a
couple degrees below normal for late August.

&&

.AVIATION /06Z Wednesday THROUGH Sunday/...
Drier air continues to work into the area. With that said still
seeing some strato cu developing over the lake from about LPR
east. These clouds should scatter out by daybreak. A fair amount
of sunshine is likely this morning before we cu back up toward
midday. Some of the guidance is hinting at some instability
showers later this afternoon. Coverage will be under 20 percent
so confidence is too low to justify even a vicinity mention at
this time.  W to NW flow will pick this morning.

OUTLOOK...MVFR possible in morning fog Thursday through
Saturday.

&&

.MARINE...
Will continue with the small craft headline as it is and extend the
beach hazards through Wednesday east of Avon point. Southwest winds
roughly 15 to 25 knots on the lake with deepening low pressure in
Quebec. The trailing cold front just northwest of the lake will
cross the lake late this afternoon through the evening hours.
Behind the boundary winds will turn northwest and should drop
off to 15 to 20 knots through the night and into Wednesday ahead
of another surface trough before diminishing in the west during
the afternoon. Wednesday night and Thursday the coldest air of
the system should be across the lake so added waterspouts to the
forecast. Friday and Saturday high pressure will dominate.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement through this evening for OHZ011-012-
     089.
     Beach Hazards Statement until 4 AM EDT early this morning for
     OHZ010.
PA...Beach Hazards Statement through this evening for PAZ001.
MARINE...Small Craft Advisory until 10 PM EDT this evening for
     LEZ146>149.
     Small Craft Advisory until 4 AM EDT early this morning for
     LEZ142>145.

&&

$$
SYNOPSIS...Oudeman
NEAR TERM...Mottice/Oudeman
SHORT TERM...TK
LONG TERM...KEC/TK
AVIATION...Kubina
MARINE...TK



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