CLE issues Area Forecast Discussion (AFD) at Oct 15, 8:06 PM EDT864
FXUS61 KCLE 160006
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
806 PM EDT Tue Oct 15 2024
.SYNOPSIS...
A trough lingers over the Lake Erie region and Upper Ohio Valley
through Wednesday morning. Our area will be impacted by a ridge
later Wednesday through this upcoming weekend as the parent
high pressure center moves from the Upper Midwest toward the
central Appalachians.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
630 PM Update...
Temperatures have begun to cool quicker across the south central
counties, with temperatures in Millersburg already dropping into
the upper 30s. With scattered clouds expected across this area
through the night, expecting those temperatures to continue to
cool a bit overnight. As a result, opted to issue a Frost
Advisory for Richland, Ashland, and Holmes Counties with this
update, which is just east of the ongoing Freeze Warning. Will
have to continue to monitor trends in temperatures to see any
enhanced cooling even further east of this, but given cloud
cover is expected to become more widespread, not expecting to
have to further extend the advisory. Aside from this, not
further changes were needed with this update.
Previous Discussion...
Troughing at the surface and aloft exits slowly SE'ward from
the Lake Erie region and Upper OH Valley, including our CWA,
through tonight as a ridge attempts to build from the north-
central United States and vicinity. A sufficiently- cold/moist
mean low- level flow varying between NW'erly and N'erly over and
downwind of ~18C Lake Erie persists through tonight and will
maintain at least moderate lake-induced CAPE (LICAPE) over the
lake. Lake- effect rain showers, heavy at times, will continue
to impact locations generally south and southeast of the lake,
especially across north-central OH to NW PA. The heaviest/moist-
persistent rain showers through tonight will be focused across
the Cleveland metro area and then shift E'ward toward the
primary snowbelt of NE OH and vicinity as mean low-level flow
backs slightly and an upstream moisture connection to Lake Huron
persists. The unusually-cold air mass and LICAPE of at least
100 J/kg within the hail growth zone will allow periodic graupel
and pea-size hail to occur. Isolated instances of lake-effect
lightning are expected through the wee hours of Wednesday
morning as LICAPE remains at least 200 J/kg within the primary
electrical charge separation zone and lake- induced equilibrium
levels (LIEL's) remain colder than -20C. However, LICAPE will
begin to decrease and LIEL's will warm/lower toward daybreak in
response to a lowering subsidence inversion accompanying the
aforementioned ridge, which will bring an end to the potential
for lake-effect lightning.
Widespread lake-effect cloud cover will contribute to limited
nocturnal cooling this evening through daybreak Wednesday
morning across much of north-central OH, NE OH, and NW PA, where
lows are expected to reach mainly the 35F to 45F range around
daybreak. The mildest lows are expected along and immediately
downwind of ~64F Lake Erie as NW'erly surface winds result in
onshore flow. A Freeze Warning remains in effect from 2 AM to 9
AM EDT Wednesday from roughly Lucas County to Knox County and
points to the southwest. This is where considerable clearing and
easing of surface winds are expected to result in greater
nocturnal cooling this evening through daybreak Wednesday, when
widespread lows of 30F to 35F and widespread frost formation
are expected.
The aforementioned ridge aloft continues to build from the
north-central United States and vicinity Wednesday through
Wednesday night. The surface portion of the ridge will also
build into the eastern Great Lakes and Upper OH Valley from the
western Great Lakes and vicinity. Primarily fair weather is
expected due to stabilizing subsidence accompanying the ridge.
Lingering lake-effect rain showers and perhaps graupel across NE
OH and NW PA, amidst sufficiently-cold/moist NNW'erly to
NW'erly mean low-level flow over and downwind of Lake Erie are
expected to begin to taper by daybreak Wednesday morning and
then end by late evening as LICAPE wanes via low-level dry air
advection and continued lowering of the subsidence inversion.
The steadiest to heaviest and most-persistent lake-effect rain
showers are expected in a corridor just east of Cleveland and
just west of Youngstown due to an upstream moisture connection
to Lake Huron and resulting corridor of greater LICAPE over Lake
Erie. Note: Additional rainfall amounts of 0.50" to 0.75" are
expected in the heaviest/most-persistent lake-effect rain late
this afternoon through Wednesday evening.
Highs are expected to reach only the mid 40's to lower 50's in
NW PA and the upper 40's to upper 50's in northern OH Wednesday
afternoon as an unusually-cold air mass persists in the eastern
Great Lakes and Upper OH Valley. Considerable clearing generally
from west to east Wednesday evening through daybreak Thursday
morning, surface winds becoming light or calm, and limited
humidity at/near the surface will promote greater nocturnal
cooling. Widespread lows in the upper 20's to lower 30's are
expected inland from Lake Erie and another Freeze Warning or at
least Frost Advisory is anticipated. "Warmer" lows in the mid
30's to lower 40's are expected along and closer to Lake Erie.
As a result, less or no frost formation is forecast closer to
and especially along the lake.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
High pressure will be firmly in control to end the work-week. Fair
weather with mainly clear skies and light or calm winds can be
expected. There will be a bit of a lingering chill to the airmass
though gradual recovery will be starting. Highs on Thursday will
range from the mid to upper 50s in far northeast OH and northwest
PA, with low 60s more common from Cleveland on west. We'll gain
several more degrees for Friday, with low to mid 60s most common,
possibly pushing upper 60s in Findlay and Marion. Conditions will be
favorable for radiational cooling both Thursday and Friday nights,
especially across the southeastern half or so of our forecast area
closest to the center of the high where winds should have an easier
time decoupling. The coldest lows will be in valleys and lower-lying
areas. For Thursday night, have lows generally in the low to mid
30s. Northwest Ohio and the immediate lakeshore will be on the
milder side. Some colder spots from portions of interior northeast
OH into inland northwest PA may sneak into the upper 20s. It will
trend a few degrees milder Friday night, though some frost is still
likely in portions of interior eastern OH and PA with a few colder
spots east potentially dipping below freezing for one more
night.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Retreating high pressure will lead to continued fair and quiet
weather with gradually moderating temperatures. Highs are forecast
to return to the 70s by Sunday or Monday. A cold front may approach
by Tuesday night, though we have no precip chances in the forecast
for the entire extended period through the day Tuesday.
&&
.AVIATION /00Z Wednesday THROUGH Sunday/...
Predominately VFR conditions are being observed across the area,
with the exception of areas receiving lake effect rain showers.
When impacted by these scattered showers, visibilities have
dropped to as low as 4SM and ceilings have diminished to 2-3kft.
This will continue to be the trend from terminals along and east
of I-71 throughout tonight and into the first half of Wednesday.
The tricky part with the forecast for all of these terminals is
that any precipitation will be lake effect driven, making it
very scattered in nature. To account for this, opted to begin
the TAF with a TEMPO for rainfall and MVFR conditions, switching
near 06Z to PROB30 for the same conditions with confidence in
persistent showers not high. By Wednesday morning, opted to
handle precipitation with VCSH as confidence is low at where the
most persistent bands will occur. The good news is that by the
end of the period, showers should end and conditions should
improve to widespread VFR. For the far western terminals, VFR
conditions will persist through the entire period.
Winds through the period will persist from the north-northwest
at 5-10 knots. The exception will be at KERI and KCLE where a
strong flow off of Lake Erie will enhance winds to be sustained
overnight at 10-15 knots, gusting up to 20 knots at times. Winds
will become light and variable near 00Z Thursday,
Outlook...Scattered lake-effect rain showers will bring the
potential for non-VFR conditions across NE OH and NW PA through
Wednesday evening. VFR conditions return Wednesday night into
this weekend.
&&
.MARINE...
Active marine conditions will continue for another day or so. North-
northwest winds will increase to 15-25 knots into this evening,
perhaps briefly slightly over 25 knots over parts of the central
basin. Winds will gradually diminish Wednesday into Wednesday night,
forecast to drop below 15 knots lake-wide Wednesday evening. Winds
are then forecast to remain below 15 knots through the weekend over
the lake. Small Craft Advisories will kick in for the entire lake by
early this evening. Waves will be largest between the Islands and
Geneva-on-the-Lake at 4 to 7 feet. Small Craft Advisories start
coming down east of Geneva and west of The Islands Wednesday
morning, and run into the afternoon in between where waves will take
longer to subside below 4 feet. After these headlines expire none
are expected for at least the next several days.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Freeze Warning from 2 AM to 9 AM EDT Wednesday for OHZ003-
006>008-017-018-027-028-036-037-047.
Frost Advisory from 2 AM to 9 AM EDT Wednesday for OHZ029-030-
038.
PA...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for LEZ142-143-
148-149.
Small Craft Advisory until 5 PM EDT Wednesday for LEZ144>147.
&&
$$
SYNOPSIS...Jaszka
NEAR TERM...Campbell/Jaszka
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Campbell
MARINE...Sullivan
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 15, 8:06 PM EDT---------------
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