Area Forecast Discussion
Issued by NWS Cleveland, OH

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000
FXUS61 KCLE 221759
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
159 PM EDT Tue Aug 22 2017

.SYNOPSIS...
A strong cold front will move east across the area late
this afternoon. A trough of low pressure will move southeast across
the area Wednesday. A large area of high pressure will build
southeast into the central Great Lakes for the latter half of the
work week and persist into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Adjustments made with this mid morning update was to put more
detail into the PoP/precip chance grids and to temperatures. Detail
does not really come out in the text of the forecast, one would
have to look toward an hourly forecast. Other minor changes were
made to the forecast for Wednesday.

Have accounted for new development out ahead of last nights
diminishing convection. Brought high temperatures down as most
of the area will be mostly cloudy and those that started out
clearer are rapidly clouding up. Severe potential especially for
east half focused more on a pre-frontal trough rather than the
cold front itself back the Chicago area. Threat will be before
7PM with a few isolated/scattered showers possible back with the
front later this evening. Areas within SPC enhanced risk area
has the mention of severe in the forecast now. Front moves
across this evening.

A trough of low pressure will move southeast toward the area
Wednesday. This will set up a lake enhanced threat of rain
showers in the northeast so will mention a chance of showers
across north-central and northeast OH/nw PA starting Wednesday
afternoon. Otherwise, the rest of the forecast area should see
fair weather through the day Wednesday.

Overnight lows will definitely be cooler after the frontal
passage. Same goes for tomorrow with cold air advection taking
place from the west and northwest.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A series of short waves is progged to drop through the unseasonably
deep trough aloft over the Great Lakes and eastern Canada the second
half of the week. The first short wave, combined with cooler air
aloft, could produce a shower or two in the snowbelt Wednesday
night. A more impressive looking short wave is progged to drop
across the eastern Great Lakes late Thursday. The air mass at the
surface will be relatively dry and stable but with steepening lapse
rates and the August sun we should be able to generate some showers
on Thursday, mainly over northeast OH and northwest PA. A few of the
showers could linger into Thursday night in the snowbelt. Cannot
rule out thunder but will keep it simple for now and just mention
showers.

Temperatures will be unseasonably cool with highs generally in the
upper 60s and lower 70s Thursday and Friday and lows in the
lower/mid 50s except warmer at the lakeshore. Lows Friday night will
tickle the 40s in many inland areas.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
The upper air pattern looks blocked by the weekend into early next
week with the trough locked over the northeast and ridging out west
and off the mid Atlantic Coast. Surface high pressure will be very
slow to move east and remain over eastern Canada. This will provide
an extended period of fair weather with temperatures only slowly
moderating and remaining below normal. Forecast highs in the 70s and
lows mostly in the 50s. There could be some high clouds from the
plains states by Sunday and especially Monday. Continuity has a
mention of showers/storms by Monday and will step that down to a
slight chance for now.

&&

.AVIATION /18Z Tuesday THROUGH Sunday/...
Convective activity will be confined to the remainder of the
afternoon hours and maybe a stray shower this evening. IFR
within the thunderstorms and MVFR within the heavier showers.
Southwest intermittent gusts to 25 knots possible through
evening. Wind shift to the west will take place when the cold
front crosses the terminals, between 23Z TUE and 04Z WED. VFR
conditions expected overnight and into Wednesday morning,
but there is an outside chance of MVFR vsby early Wednesday
morning if winds end up being lighter.

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

&&

.MARINE...
A strong cold front will push across Lake Erie this afternoon and
evening and mariners will have to be alert for potentially multiple
rounds of gusty showers and thunderstorms. The southwest wind will
be enhanced ahead of the front as a nice low level jet spreads
across the eastern Great Lakes today. The flow will become west to
northwest late this afternoon and tonight behind the front. Small
craft advisories will remain in effect.

The weather pattern will suddenly become fall-like the second half
of the week. High pressure will build in from the west on Wednesday
but the WNW flow will remain brisk on the east half of the lake and
will extend the small craft advisory through the day Wednesday from
Avon Point east.

A weak secondary front/trough will drop across the lake on Thursday.
It will be cold enough aloft for a few showers and perhaps a
waterspout. High pressure will build across eastern Canada this
weekend and an extended period of northeast to east flow will
develop. Wind speeds may be just strong enough for the west half of
the lake to get choppy by early next week.

&&

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

&&

$$
SYNOPSIS...Lombardy
NEAR TERM...Lombardy/Oudeman
SHORT TERM...Kosarik
LONG TERM...Kosarik
AVIATION...Oudeman
MARINE...Kosarik



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