CLE issues Area Forecast Discussion (AFD) at Oct 7, 1:54 AM EDT609
FXUS61 KCLE 070554
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
154 AM EDT Mon Oct 7 2024
.SYNOPSIS...
Strong cold front continues to sweep east across the area
through this evening. Canadian high pressure builds overhead
behind the cold front Monday and will persist through the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
910 pm update...
The only minor adjustment made with this late evening forecast
update was with the hourly POPs from late tonight through early
Monday afternoon. We knocked down the POPs just a tad regarding
a few scattered lake effect rain showers possible in far NEOH
and NWPA on Monday. We left the POPs between 20 and 30 percent.
715 pm update...
As of this mini forecast update, we have cancelled the rest of
the severe T'storm watch for NEOH and NWPA. We have also
tweaked the hourly POPs for the rest of the evening as the
convection and rain chances have exited east of the CWA. The
rest of the forecast is on track through tomorrow.
Previous discussion...
Broad upper level trough will continue to drag a cold front eastward
across Northern Ohio and Northwest Pennsylvania before exiting early
this evening. Behind the front, lingering upper level energy sags
south which will supply a brief window for lake effect clouds
and rain showers before Canadian high pressure builds overhead.
Already seeing much drier air upstream behind the front in Northern
Indiana with dew points in the 30s and RH values between
15-25%. Expect for this dry air to work itself into Northwest
Ohio this afternoon and evening. The combination of wind gusts
between 25 and 35 MPH, low RH values, and dry vegetation has led
to an elevated risk of fire spread through early this evening
across Northwest Ohio. 10 hour fuels remain a bit too high for
Red Flag criteria, so kept the Special Weather Statement in
effect through this evening.
At his point we are beginning to see a cu field develop along
the I-71 corridor as the cold front surges eastward into an
unstable environment. Sufficient daytime heating has allowed
for MLCAPE values to rise into the 1000-1500 J/kg range with
deep layer shear of 30-40 knots. Still anticipating for
thunderstorms to initiate fairly quickly over the next few
hours with initiation generally occurring along a line from
Ashtabula to Canton and points east. Strong to severe
thunderstorms with all hazards (damaging winds, large hail, and
a few tornadoes) remain on the table in an unstable environment
with plentiful deep layer shear. Primary hazards continue to be
damaging wind gusts and large hail, but can't rule out rotating
updrafts and/or few tornadoes given ample deep layer shear and
low LCLs. As such, portions of Northwest Pennsylvania and
eastern Ohio remain in a Slight Risk (Level 2/5) for severe
weather this afternoon and early evening.
The cold front quickly exits to the east tonight ushering in a
much cooler airmass. Overnight lows tonight dip into the mid
40s inland with low 50s in place along the lakeshore. Upper
trough and shortwave aloft dip south tonight into tomorrow which
will allow for lake effect clouds and rain showers to develop
downwind of Lake Erie. Northerly flow will keep cooler
temperatures in place with highs on Monday ranging between the
mid/upper 50s in Northwest Pennsylvania to the low to mid 60s
across Northern Ohio. Canadian high pressure builds overhead
through Monday which will lead to improving conditions but
another chilly night with lows dipping into the lower 40s.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Low impact weather will continue through mid-week, along with
traditionally cool Fall temperatures as deep mid/upper troughing
persists across the Great Lakes and eastern Canada.
The mid/upper longwave trough axis will be located across the Great
Lakes Tuesday, gradually shifting into New England Wednesday and
Wednesday night as the associated closed low drifts from northern
Ontario to the Canadian Maritimes. This will allow a large area of
cool Canadian high pressure at the surface to shift from the heart
of the Midwest Tuesday to over the Great Lakes and Ohio Valley by
late Wednesday and Wednesday night. This pattern all points to
seasonably cool fall temperatures, with generally low to mid 60s for
highs both Tuesday and Wednesday. Far NE Ohio and NW PA will stay in
the upper 50s, while NW Ohio sees upper 60s. Lows will generally be
in the 40s both nights, with upper 30s along the US 30 corridor and
in interior NE Ohio and NW PA. Wednesday night has the better chance
for 30s as the high builds in to set up better radiational cooling,
so frost is possible in interior NE Ohio and NW PA.
Before the high builds in, NW boundary layer flow across Lakes Huron
and Erie combined with moderate to strong lake induced instability
will generate some lake-effect rain showers Tuesday into Wednesday
in far NE Ohio and NW PA. This entire window will likely see some
showers, but late Tuesday and Wednesday morning will have the
greatest coverage as a final shortwave drops through the mean
mid/upper trough with 850 mb temps dropping to just below 0 C over
the eastern basin of the lake and equilibrium levels rising to 15-16
thousand feet. This will yield extreme instability of 650-900 J/Kg,
so have solid chance PoPs. Also added thunder given the instability.
Shear at times seen in NAM BUFKIT forecast soundings and pretty dry
air overall will limit the organization of this activity.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
The aforementioned large Canadian high will gradually settle from
the Great Lakes and Ohio Valley Thursday to the Tennessee Valley
Friday as a strong mid/upper shortwave trough drops through the
Great Lakes and NE CONUS Saturday into Sunday. An associated deep
surface low moving through northern Ontario will drag a strong cold
front across the region Saturday night or Sunday which will bring
the next potential for rain showers. Timing of the front is
uncertain 7 days out, but at this point, limited moisture advection
ahead of the front will limit QPF despite what looks to be strong
synoptic forcing. This will unfortunately keep drought conditions
status quo.
Highs will remain cool in the low to mid 60s Thursday, with upper
50s continuing in far NE Ohio and NW PA and upper 60s in NW Ohio.
Warm air advection ahead of the front will boost highs into the low
to mid 70s Friday and possibly mid 70s to near 80 Saturday.
Temperatures should cool into the upper 60s to low 70s Sunday.
&&
.AVIATION /06Z Monday THROUGH Friday/...
Cyclonic northwesterly flow will allow for some strato-cumulus
at times through the TAF period. The greatest potential for them
to be BKN-OVC is at CLE, CAK, YNG and ERI due to flow off of
Lake Erie, though TOL and MFD may briefly go BKN for a few
hours early this morning too. These are mainly VFR, though
suspect there will be a few hours of MVFR from CLE and CAK
points east this morning. A few light lake effect showers are
possible at ERI and perhaps YNG, mainly between about 10-16z
this morning, though restrictions are unlikely. High pressure
and drier air will allow skies to clear out even downwind of the
lake towards this evening.
Northwesterly winds of 5 to 12 knots are generally expected
through this afternoon, with a few gusts up to 20 knots through
this morning at CLE and ERI. Winds will turn more west-southwest
and decrease to less than 7 knots across the board this evening.
Outlook...Generally VFR conditions expected this week.
&&
.MARINE...
W to SW winds of 15-25 knots across Lake Erie will continue until a
strong cold front crosses the lake this evening. This will veer
winds to NW at 20-30 knots early tonight before NW winds decrease to
15-25 knots. NW winds will gradually decrease to 10-15 knots Monday.
These winds will build 4 to 8 foot waves late this evening and
tonight, especially in the central and eastern basins, so Small
Craft Advisories will continue on the entire lake through 20Z
Monday. NW winds will then average 10-20 knots through Wednesday
before turning light and variable by late Thursday, then SW at 10-20
knots Friday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT early this morning for
LEZ142-143.
Small Craft Advisory until 4 PM EDT this afternoon for
LEZ144>149.
&&
$$
SYNOPSIS...Iverson
NEAR TERM...Griffin/Iverson
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Sullivan
MARINE...Garuckas
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 7, 1:54 AM EDT---------------
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