425 
FXUS61 KCLE 130714
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
314 AM EDT Mon Sep 13 2021

.SYNOPSIS...
A frontal boundary will stall this evening near the southern 
shores of Lake Erie. This front will lift north as a warm front 
Monday into Tuesday ahead of another cold front expected to move 
east across the area on Wednesday. High pressure will build across 
the area behind the front.

Stationary front lifts back northeastward later today as a warm
front. Cold front arrives and passes Tuesday night/early
Wednesday. Weak high pressure moves from the northern plains
through the Great Lakes and into eastern Canada by Thursday
night.

&&

.NEAR TERM /THROUGH TUESDAY/...
Developing trough axis over the northern plains moving into the 
Great Lakes will foster cyclogenesis which will serve to lift the 
stationary boundary along the southern shore of Lake Erie back to 
the northeast as a warm front. Convective activity will thus be 
relegated north of the region where the better low/mid level f-gen 
resides and a weak wave aloft will pass west to east, with the 
exception of far NE OH/NW PA. By 12 Z Sunday, the entire CWA should 
be back into an atmosphere with a deep warm layer over several 
thousand feet above the boundary layer. Cold front approaches NW OH 
Tuesday as vertical profiles become more conducive to convective 
activity with lowering LFCs and ultimately increased CAPE. Still 
will have to work around a shallower warm layer now relegated to the 
mid levels as well as some dry air in the column. A prefrontal line 
of convection is possible, but overall, POPs run low prior to the 
arrival of the cold front, right around the break point with the 
short term period. Low level winds increase with 25-35kts and 0-6m 
bulk shear. Will be watching some organized convection moving 
through MI/IN/IL Tuesday afternoon.

Temperatures above normal again in the warm sector, with the 
exception of NW PA where low stratus development today should hold 
off some of the heating, and 70s are likely as opposed to mid to 
upper 80s elsewhere.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
On Tuesday evening, a cold front associated with a low pressure 
centered over Quebec will be located near the far northwest 
counties. This boundary is expected to move east-southeast across 
the area overnight Tuesday into Wednesday, bringing widespread 
showers and thunderstorms. As the broad upper level trough continues 
to move the low pressure further east, the cold front is expected to 
become an east/west oriented stationary front across the area on 
Wednesday. This boundary will likely become the focus of additional 
shower and thunderstorm development, with convective instability and 
high deep layer shear values supporting the potential for severe 
storms. Current models suggest the primary threat would be centered 
across the southeastern portion of the area where the best 
instability will develop, with strong winds remaining the primary 
threat. The chance of flooding across the area will also need to be 
monitored as the boundary because near parallel to the upper level 
flow, which will be conducive to training convection. Current models 
forecast PWAT values of 1.5-1.8 inches and warm cloud layers over 11 
kft. An Day 2 Marginal ERO has been issued for far NW OH as the 
front approaches, however an updated ERO for Day 3 has not been 
issued at the time of this discussion. Would anticipate this 
marginal risk for excessive rainfall to shift further east on 
Wednesday due to current storm total rainfall values of 0.5-1.25 
inches. 

Overnight on Wednesday, the aforementioned stalled boundary will 
begin to lift north as a warm front, again placing the area in the 
warm sector of a low pressure centered north of Ontario. This will 
allow for the rain to move out of the area and winds to become light 
and variable. There is a chance for scattered diurnally driven 
convection across the area Thursday afternoon, but these showers 
should quickly subside after sunset leaving the area dry Thursday 
night. High temperatures on Wednesday will be in the mid 70s to low 
80s with the coolest temperatures north of the stalled boundary. 
Temperatures will warm again to the upper 70s to mid 80s across the 
area on Thursday. Overnight lows will be in the 60s.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
There remains quite a bit of uncertainty through the long term 
period as the aforementioned low north of Ontario continues to move 
east with a broad upper level trough. A cold front is expected to 
extend south in the Midwest, however the exact timing of the 
progression of this boundary is not handled consistently amongst 
models, along with any consistency in the upper air pattern. As a 
result of the uncertainty in forcing, have opted to keep isolated 
chance of diurnally driven PoPs through Sunday. High temperatures 
are expected to remain above average in the low to mid 80s with 
overnight lows above average in the mid to upper 60s.

&&

.AVIATION /06Z Monday THROUGH Friday/...
Convection tracking over NW PA should be waning over the next
few hours, but underneath an inversion in this area, low stratus
in the MVFR range is expected to form overnight/early Monday
morning, and also over at TOL. Carry hints of the low stratus 
at CLE/CAK/YNG as well, but do not think the coverage will be 
enough for a ceiling and leave it at SCT. The frontal boundary 
responsible for the convection and the low stratus should lift 
back north as a warm front today. Otherwise, VFR with winds
generally under 12kts. Depending on how far south the front
drifts, winds along the lake shore terminals may need to go to a
NE direction with the winds after 16Z or so.
 
Outlook...Non-VFR possible with showers/thunderstorms through 
Tuesday. Non-VFR likely Wednesday in showers and thunderstorms 
associated with a cold front.

&&

.MARINE...
A stationary boundary currently located near the southern shore of 
Lake Erie has allowed winds weaken across the much of the area to 5-
10 knots from the northeast. These conditions are expected to 
persist through Monday evening before the aforementioned boundary 
becomes a warm front and lifts north across the lake tonight into 
Tuesday. This will result in a brief increase in northeasterly winds 
to 10-15 knots, gusting to 20 knots ahead of the front, 
transitioning to southwesterly winds near 10 knots by Tuesday 
morning. Winds are expected to increase throughout the day on 
Tuesday with winds across the western and central basins of 15-20 
knots from the southwest. This will keep the largest waves north 
along the northern shore of Lake Erie. Winds will weaken behind 
another cold front that will move east across the lake Wednesday, 
eventually stalling over central Ohio. Winds of 5-10 knots will 
persist into the beginning of the weekend. No marine headlines are 
anticipated at this time, however will need to monitor the strong 
winds on Tuesday. 

&&

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

&&

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