228 
FXUS61 KCLE 230007
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
707 PM EST Sun Jan 22 2023

.SYNOPSIS...
Low pressure over the southern Appalachians moves off the Mid- 
Atlantic Coast tonight. A surface trough lingers over the area 
late tonight through Monday afternoon. High pressure briefly builds
over the region late Monday into Tuesday. The next area of low 
pressure develops over the Southern Plains by mid-week then 
tracks northeastward to the Ohio River Valley Wednesday. 

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
Finally seeing a defined back edge to the accumulating snow 
that was located from near Cleveland southward to Mount Vernon
as of 7 pm. We have dropped portions of the Mid Ohio Region 
from the winter weather advisory. Will keep headlines for areas 
east of I-71 into NW PA. The main thing we will need to monitor
is how much lake enhanced snow redevelops in the wake of low 
pressure that moves off the Mid-Atlantic Coast overnight. 
Current thinking is that we do see some development but 
temperatures are not all that cold. Since the dendritic growth 
zone is above the best of the low level lift the snowflakes
should become much smaller. This makes it difficult to get 
significant accumulations. So after the main area of snow moves 
east of the CWA near or after midnight any additional amounts 
will struggle to be more than an inch. Locally higher amounts
near 2 inches are possible where the northerly upslope flow is 
maximized.


So expect us to gradually remove the remaining winter weather
advisories through the overnight. 


Previous Discussion...
Widespread snowfall continues this afternoon as a positively 
tilted upper level trough supports a surface low tracking 
northeast towards the Mid-Atlantic Coast. This has left northern
OH and northwest PA in an ideal location for heavy snowfall 
development, especially along and east of I71. Models have begun
to suggest that the 700mb frontogensis is weakening, however 
strong upper-level synoptic support is pushing over the area, 
essentially replacing one strong forcing with another. In 
addition, the DGZ remains saturated with a cross hair signature 
observed on model soundings. Due to these continuing conditions,
portions of NE OH and NW PA may continue to periods of 1"/hr 
snowfall rates through this evening. This will result in an 
addition 1-3 inches of snow accumulation, with locally higher 
amounts. SPC has also highlighted this potential in a MCD 
concerning heavy snowfall. To highlight this potential, a Winter
Weather Advisory remains in effect through this evening with 
the exception of the snowbelt, which will remain in effect 
through Monday afternoon. Further west, conditions have slightly
improved with light snow reported at many of the observation 
sites. This will allow for slightly improved visibilities, 
however there could be some patchy areas of fog due to lingering
moisture in the lower levels, which could quickly reduce 
visibilities again. 

As the parent low pressure deepens and pushes off the Mid-Atlantic 
Coast tonight, snowfall will continue to diminish from west to east. 
There is expected to be a brief lull in snowfall for areas extending 
from Cleveland to Erie, PA before lake enhanced snowfall kicks in on 
the backside of the system. Exact timing of onset will be highly 
dependent on how quickly the column cools, but general thinking is 
between 6-9Z Monday. With a northerly wind, there is a potential of 
a Lake Huron connection, however right now models are not suggesting 
a strong connection developing. Areas across the snowbelt may see an 
additional 1-3 inches with this. The LES will persist into the early 
afternoon hours on Monday, before winds become southwesterly and WAA 
begins to push back over the area. High pressure will build over the 
area late Monday, finally cutting off the snow potential as drier 
air pushes in and persists through Monday night. The main story with 
the high pressure will be winds of 10-15 knots, gusting up to 20 
knots across the area.

Temperatures tonight and Monday night will be in the upper 20s to 
low 30s, with highs on Monday in the mid 30s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Low levels begin to warm advect Tuesday and should shut off any 
remaining lake effect snow in NW PA down for the time being. Next 
low pressure system begins to track towards Ohio from the lower 
Mississippi Valley with the leading edge of precipitation in the 
moist isentropic ascent ahead of the warm front expected to reach 
the southern CWA border before 12Z Wednesday. As of right now, this 
looks to be an efficient snow set up on the front end of this system 
with added deformation in the low/mid levels coupled with Q Vector 
convergence aloft over central Ohio Wednesday morning. The main 
issue right now in the forecast is the exact path of the surface 
low, and the positioning of it will have significant differences in 
the forecast output with shifts mere miles west or east. A further 
west track like the current GFS and NAM runs puts the CWA in a more 
prone area for warm air advection and a transition to rain, while 
others further east would favor more sustained snow, at least for 
the western portions of the CWA. With this warm air advection would 
also come a transition to mixed precipitation as well prior to turning 
to all rain. Currently have Wednesday high temperatures in the upper 
30s for much of the area. A lot of details to be worked out here, 
but the low should be northeast of the area allowing for cold air 
advection on the back side of the low, and a transition to likely 
lake effect snow.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
West northwest lake effect setup heading into Thursday in -13C 850mb 
temperatures and should expect accumulations for the snow belt 
regions from Wednesday night through early Thursday night. Should 
shut off with winds coming around to the southwest by Friday morning 
with the development and deepening of a low pressure clipper system 
tracking into the northern Great Lakes. Not much snow from this, but 
a reinforcing cold front expected around early Saturday followed 
quickly by high pressure that will be short lived. Temperatures near 
normal for late January.

&&

.AVIATION /00Z Monday THROUGH Friday/...
Steady light accumulating snow continues across NE OH into NW PA
this evening. The back edge of the this area of snow was 
located from near KCLE to K4I3 as of 00z and is expected to
continue a slow move to the east. Likely clearing NW PA around
06Z. We will then monitor for some lake enhanced snow from the
Mid Ohio region to NW PA. It doesnt look all that heavy but will
reduce conditions to IFR, especially from 07Z to 13Z. 

So expect to see a continuation of IFR conditions across the 
east then slowly rising ceilings from west to east through the 
overnight. Ceilings and visibilities will be reduced back down 
to IFR levels late tonight through at least sunrise from the Mid
Ohio Region to NW PA. 

Winds remain light but will be from a northerly direction
through sunrise. Winds continue to shift to the west and
southwest through Monday afternoon. Speeds also increase to 
greater than 10 knots, likely becoming gusty across the western 
half of the region. Gusts around 20 knots are possible. 

Outlook...Non-VFR returns Tuesday night into Wednesday in 
rain/snow.

&&

.MARINE...
Southwest winds increase 15-25kts heading into Monday due to a low 
pressure system tracking to the east of Lake Erie with wave heights 
3-6 feet from Vermilion east to Dunkirk NY. Have hoisted a Small 
Craft Advisory beginning 21Z Monday for these conditions which will 
run for 24hrs to 4pm Tuesday. Winds ease into Tuesday night and turn 
easterly 15-20kts Wednesday ahead of the next low pressure system 
moving into the region from the southwest. Wednesday night, the 
surface low pushes northeastward across the lake, and winds turn 
northwesterly behind it 15-20kts Thursday with wave heights on the 
increase again.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Winter Weather Advisory until 10 PM EST this evening for 
     OHZ010-020>023-030>033-038-047.
     Winter Weather Advisory until 1 PM EST Monday for OHZ011>014-
     089.
PA...Winter Weather Advisory until 1 PM EST Monday for PAZ001>003.
MARINE...Small Craft Advisory from 4 PM Monday to 4 PM EST Tuesday for 
     LEZ145>149.

&&

$$
SYNOPSIS...Campbell/MM
NEAR TERM...Campbell/MM
SHORT TERM...26
LONG TERM...26
AVIATION...MM
MARINE...26