772 
FXUS61 KCLE 092119
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
419 PM EST Sat Nov 9 2019

.SYNOPSIS...
Stemming from low pressure moving east across southern Canada a
cold front will cross the Great Lakes tonight and Sunday and
reach the local area Sunday night. The front will stall
southeast of the area on Monday as low pressure moves along the
front. Tuesday and Wednesday high pressure will overspread the
western Great Lakes and Ohio Valley with unseasonably cold air 
while a trough lingers across the eastern Great Lakes.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
Uneventful tonight and early Sunday as we benefit from return
flow on the backside of high pressure that made its way to the
mid-Atlantic coast. Some temporary thinning of the cloud decks 
is expected for a time tonight, but thicken again for Sunday. 
Lows tonight will be 5 to 10 degrees warmer than last night and 
likely be coldest earlier in the night before the clouds thicken
back up before daybreak.

A warm front will lift north across the area Sunday.
Temperatures will warm close to 50. The cold front will be
nearing northwest OH and Erie, PA by late afternoon and with it
arrives the rain chances. Kept everyone else dry during the
afternoon, but could get a few sprinkles prior to sunset just
about anywhere. 

Precipitation develops overhead Sunday night as the upper trough
approaches and a surface wave begins to develop along the cold
front across southeast OH/southwest PA. With cold air on its
way and the H8 front just to our northwest, have snow or a mix 
mentioned "at the corners" (northwest Oh/northwest PA) before 
sunrise and temperatures down to the lower/mid 30s. Snow 
accumulation at this point would only be a coating for the 
Toledo area.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A deep and large upper level trough currently over the northern
parts of Canada is expected to swing down into the CONUS, with 
the trough axis over the Midwest by Monday afternoon and the 
central Great Lakes by Tuesday morning. A surface cold front 
extending from weak low pressure over southern Quebec with move 
southeast across the area on Sunday night and stall out across 
southern Ohio and into the New England coast. Low pressure is 
expected to develop along this front over the Ohio Valley on 
Monday and move east to the New England coast by Tuesday 
morning. Moisture originating from the northern Atlantic will 
accompany the upper level trough. Favorable jet dynamics along 
with the upper level trough will provide synoptic forcing for 
ascent across the area. These key environmental variables will 
result in widespread precipitation beginning as rain early 
Monday morning and transitioning to all snow by Monday evening. 
While there is fair amount of agreement in the large-scale 
details, there are some differences with QPF amount, timing, and
temperature. The most likely scenarios is more widespread 
snowfall of around one to two inches with locally higher amounts
through about 12Z Tuesday (not including lake effect snow). The
aforementioned model variability could result in some 
adjustments to these numbers.

The event quickly transitions to lake effect snow late Monday night 
as the trough crosses the Great Lakes. With lake surface 
temperatures around 10 deg C, 850 mb temperatures cooling down to as 
low as -16 deg C, and 700 mb temperatures down to -27 deg C, extreme 
instability is expected over Lake Erie, with lake induced CAPE as 
high as 1000 J/kg on Tuesday. Additionally, cloud depths in excess 
of 10,000 feet can be expected as well. With plenty of residual 
environmental moisture and this kind of instability, we can expect 
several intense lake effect bands to set up with the possibility for 
thundersnow on Tuesday and Tuesday night. North to northwest flow 
will result in multibands across the primary and secondary 
snowbelts. Winds will be continuously transitioning from north to 
northwest with many models hinting at several perturbations in the 
flow on Tuesday and Tuesday night. These perturbations could result 
in disruptions in the organization of bands that do setup on 
Tuesday. Regardless, widespread snowfall is expected on Tuesday and 
Tuesday night with significant snowfall possible in some areas. It 
will be important to monitor the forecast in the coming days as this 
could be the first significant snowfall for many.

In addition to accumulating snowfall, very cold temperatures are 
expected, with potentially record-breaking lows on Tuesday and 
Wednesday. High temperatures are expected to stay below freezing on 
Tuesday.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Lake effect snow showers will gradually end Wednesday morning 
as the 850 mb ridge axis crosses Lake Erie. The center of the 
arctic high is expected to translate from the central Great 
Plains to the Ohio Valley by Wednesday morning, which is when we
expect the coldest temperatures of the week to occur. Low 
temperatures Wednesday morning are expected to generally be in 
the teens, with our current low forecast near record levels for 
all six of our climate sites. High temperatures continue to 
remain below freezing all day Wednesday. Warming trend begins 
Thursday and Friday as high pressure moves to the east. A 
clipper system may bring light snow or rain on Thursday. High 
pressure approaches from the west on Friday and Friday night.

&&

.AVIATION /18Z Saturday THROUGH Thursday/...
VFR conditions to continue with mid/high clouds across the
terminals. South-southwest winds will have minor gusts to 20
knots this afternoon. Winds begin to shift to the west-southwest
starting in TOL/FDY near 18Z Sunday with the approach of a cold
front. This front will bring the MVFR ceilings. Much of the
precip will hold off until after 18Z Sunday although some light
rain/drizzle will be just north of TOL/ERI and across the lake. 

.OUTLOOK...Non-VFR likely Sunday night through Monday night 
with widespread precipitation. Non-VFR expected Tuesday and 
Wednesday with lake effect snow showers.

&&

.MARINE...
Southwest winds to continue to be around 15 to 20 knots through
Sunday morning. As mentioned on the previous shift, decided not
to go with a Small Craft Advisory due to marginal wind strength
with a large offshore component. A cold front moves southeast 
across Lake Erie on Sunday night and stalls out southeast of the
lake on Monday morning. Low pressure develops over the Ohio 
Valley and moves northeast along this boundary on Monday and to 
the New England Coast on Tuesday. As a result of this developing
low pressure, northeast wind of 15 to 25 knots will develop 
starting Monday. Northwest winds of 15 to 25 knots will develop 
on Tuesday as a result of the low pressure moving off to the 
northeast. This will result in Small Craft Advisory conditions 
across much of Lake Erie until winds diminish by Wednesday 
afternoon. 

&&

.CLIMATE...
Arctic air will move southeast into the local area Monday night
into Tuesday and then begin to shift east Tuesday night. The
unseasonably cold air will cause temperatures to plummet to some
of the coldest readings so far this season.  

Below are the coldest temperatures on record for selected dates
at our six climate sites:

Tuesday, November 12:

					Coldest high (year) 	Coldest low (year)

Akron-Canton Area: 	28 (1920) 				16 (1950)
Cleveland Area: 	31 (1920)				18 (1911)
Erie Area:			34 (1996)				18 (1911)
Mansfield Area:		29 (1996)				16 (1976)
Toledo Area:		30 (1995)				15 (1976)
Youngstown Area: 	30 (1996)				19 (1950)


Wednesday, November 13:

 					Coldest high (year) 	Coldest low (year)

Akron-Canton Area:	25 (1911)				12 (1911)
Cleveland Area: 	22 (1911) 				15 (1911)
Erie Area: 			23 (1911)				16 (1911)
Mansfield Area:		27 (1986)				13 (1986)
Toledo Area:		22 (1986)				13 (1911)
Youngstown Area:	29 (1996)				17 (1986)

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...Oudeman
NEAR TERM...Oudeman
SHORT TERM...Saunders
LONG TERM...Saunders
AVIATION...Oudeman
MARINE...Saunders
CLIMATE...