Area Forecast Discussion
Issued by NWS Cleveland, OH

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000
FXUS61 KCLE 240155
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
955 PM EDT Mon Oct 23 2017

.SYNOPSIS...
Low pressure will undergo rapid deepening as it moves from northern
Indiana to eastern upper Michigan overnight, pulling a cold front
east across the area. The low will linger over the Central Great
Lakes through Tuesday before tracking northeast into Canada on
Wednesday. A ridge will build over the Appalachians on Thursday with
another cold front approaching from the west on Friday.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
Have lowered PoPs through the overnight hours, especially across
central and eastern portions of the area. A large dry slot is
working its way into the region, so not much more than isolated
to scattered showers are expected after the back edge of the
rain moves through. The wind advisory has been allowed to
expire for northwest Pennsylvania. Winds may pick up for a few
hours tonight, but gusts should stay between 30 to 40 mph.

Previous discussion...
A 1001mb surface low located over NE Indiana will deepen to
980mb as it tracks to near the Mackinac Straits by 12Z Tuesday.
Meanwhile the closed upper low curling northeast through the
Ohio Valley will get absorbed into the stronger trough digging
southeast out of Canada. Favorable dynamics continue this
evening and occasional rain will continue before a dryslot wraps
in from the southwest and showers become much more scattered
after midnight. Rain has been more intermittent than expected
but several areas will still see a half inch or more.

A strengthening low level jet with 50 knots near 925mb will
develop across NE OH/NW PA in response to the deepening system
through 00Z. Winds outside of rain showers have been gusty but
it is unclear how effective the rain will be at stabilizing the
boundary layer. The gradient will be strongest in northeast Ohio
and may occasionally see winds gusting to 30-35 mph through the
evening. The strongest wind gusts remain possible in Erie
County PA where a Wind Advisory is in effect until 10 PM. It is
possible that winds peak closer to 40 mph as the rain is already
spreading in, but the downsloping component may still win out
with a few stronger gusts of 45 to 50mph so will leave the
Advisory as is. Will also have to keep an eye on the fine line
of showers moving north late this afternoon which could bring
down a few stronger gusts if it intensifies. Otherwise the cold
front swinging through this evening will also bring southwest
wind gusts of 30-35 mph.

Deep upper level trough settles over the eastern United States on
Tuesday with a closed 535dm low over Michigan. Another band of
showers will wrap in from the west on Tuesday morning ahead of the
approaching trough. Showers will be enhanced by a -28C cold pool
aloft through early afternoon before shifting north. Highs on
Tuesday will only recover by 5-7 degrees with highs in the mid 50s
expected. Cold advection continues into Tuesday night with 850mb
temps dropping to -2 to -3C. Tuesday night will be brisk with lows
near 40 and breezy conditions.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The upper trough will be over the area Wed with a surface trough
initially that weakens by evening as a ridge starts to develop north
into the region. These factors along with lake effect potential will
combine for numerous shra Wed that should shift into just the
northeast for Wed night then taper off Thu morning as lake effect
conditions become unfavorable.

The ridging will rapidly shift off to the east Thu night with
another lobe of the upper trough digging into the midwest which will
induce a surface low to move northeast thru the lakes and pull a
cold front east across the area Fri. Most models show band of sct
shra developing with the front by afternoon so will increase
Superblend guidance to show chc for a good part of the cwa.

Wed will be a chilly day with highs at least 10 degrees below
normal. Moderation of temps will take place for Thu and Fri but not
sure if Fri will be warmer than Thu in the west due to the cold
front timing.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Cold front looks to be moving across the region late Friday night
into Saturday with at least scattered showers along and ahead of it.
An upper level trough will linger across the central Great Lakes
into Monday so periods of showers will remain possible. Another
surge of cold air looks like it will arrive Sunday night into
Monday. Models are beginning to hint that a few locations could see
some snow. Something for us to monitor over the next week.

Temperatures will be below average through the long term period.
Highs will generally be in the mid 40 to lower 50s. Lows
Saturday and Sunday nights will be in the 30s.

&&

.AVIATION /00Z Tuesday THROUGH Saturday/...
All sites could see MVFR conditions at times in moderate rain,
though it is mostly just VFR showers out there. Showers will
decrease in coverage tonight as a dry slot wraps overhead but a
few showers remain possible. SE winds will shift to the
southwest winds the passage of a cold front. Wind gusts to 30
knots possible with the frontal passage except at ERI where
gusts could approach 40 knots both ahead of and with the front.
MVFR to VFR conditions with scattered showers continue into
Tuesday as the upper trough moves into NW Ohio.

OUTLOOK...Areas of Non-VFR in rain showers through Wednesday.

&&

.MARINE...
With the wx pattern change, expect the more normal SCA or near SCA
conditions to run much of the time tonight through Saturday. Winds
will waver back and forth from south to west or northwest as a
series of cold fronts push east thru the lake over the next 5 days.
There may be periods of low or near low water conditions in the
western basin when the SW to west winds are running 20 to 30
knots.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT Thursday for LEZ146>149.
     Small Craft Advisory until 4 PM EDT Wednesday for LEZ142>145.

&&

$$
SYNOPSIS...KEC
NEAR TERM...KEC/Mottice
SHORT TERM...Adams
LONG TERM...Mullen
AVIATION...Mottice
MARINE...Adams


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