CLE issues Area Forecast Discussion (AFD) at Dec 27, 9:12 PM EST828
FXUS61 KCLE 280212
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
912 PM EST Fri Dec 27 2024
.SYNOPSIS...
Low pressure will lift from the mid Mississippi Valley this
evening through the northern Great Lakes by late Saturday. This
will pull a warm front across the region tonight. The trailing
cold front will stall near western Ohio Saturday as a stronger
low pressure system develops over the Mississippi Valley and
lifts through the Ohio Valley and eastern Great Lakes Saturday
night and Sunday. This will pull the cold front east of the
region by Sunday night.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
9:12 PM EST Update...
Most of our forecast remains valid per latest trends in obs and
model guidance. Only change was to increase POP's to the likely
range across far-NE OH, NW PA, and much of central and eastern
Lake Erie to account for a swath of steadier light to
occasionally moderate rain that will sweep NE'ward through the
wee hours of Saturday morning. This swath of steadier rain is
likely associated with enhanced moist isentropic ascent amidst a
developing low-level jet (LLJ) and convergence/associated ascent
along the nose of the LLJ. Please see discussion below for
further details.
Previous Discussion...
A period of active weather will begin tonight as a warm front
lifts across the region, followed by a strengthening area of low
pressure approaching from the south Saturday night.
Regional radar and infrared satellite loops this afternoon show
a large band of showers moving into NW and north central Ohio.
This is being driven by mid-level moisture advection and
isentropic ascent in response to a 100-110 knot H3 jet streak
lifting toward the southern Great Lakes on the eastern periphery
of a compact mid/upper shortwave trough. This shortwave will
continue lifting through the southern Great Lakes tonight, with
the associated synoptic support allowing the band of showers to
progress east and northeastward through the region this evening
and tonight as the warm front lifts through. The showers will
reach the OH/PA border by 22-23Z, and once the rain begins,
there will be a roughly 3-6 hour window of showers before a dry
slot advects in behind the warm front. Far eastern Ohio and NW
PA will likely see less rainfall this evening into tonight
compared to farther west since they will be east of the greatest
synoptic support, and SE low-level winds will lead to downslope
drying. Even so, QPF will be light in the entire CWA from this
phase of the event, with no one receiving more than a few
hundredths to up to 0.10 inches.
Late tonight and much of Saturday, a dry slot will persist
across the region as we get into the warm sector as the weak
surface low lifts from Wisconsin across Lake Superior. Trended
PoPs lower from about 08Z tonight through 20Z Saturday since
there should be very little in the way of showers in the warm
sector. However, this will take us into the second phase of the
event for Saturday night and Sunday. The cold front will stall
near the IN/OH border Saturday in response to new cyclogenesis
taking place over the Lower Mississippi Valley as a stronger,
much more potent mid/upper shortwave swings out of the southern
Plains. As this shortwave trough axis crosses the Mississippi
Valley and tilts negative Saturday night, the surface low will
rapidly deepen and lift toward southern Indiana. Strengthening
dynamics from a nearly coupled upper jet structure will lead to
strong warm/moist advection and isentropic ascent as a 40-50
knot low-level jet develops from a wide open Gulf, so expect
widespread rain to move in from south to north Saturday evening
through Saturday night. The rain will be moderate to heavy at
times given the moisture advection and dynamics, with embedded thunder
possible as well due to elevated instability creeping northward
toward Sunday morning. Have steadily increasing PoPs Saturday
evening through Saturday night.
Lows tonight will reach the low/upper 40s before rising after
Midnight. This will lead to a very warm Saturday with highs in
the mid/upper 50s. Lows Saturday night will range from the
low/mid 40s.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
An upper level trough will continue to deepen across the mid-
Mississippi and move north-northeastward across the Great Lakes
region through Sunday night. The associated surface low pressure
will move into the region late Sunday and cross the western portion
of Lake Erie by Monday morning. Early Sunday the warm front will
push northward across the region bringing with it widespread
precipitation that will stay around through most of the day. Some
models, particularly the NAM, are introducing a dry slot on the
eastern portion of the low before the cold front sweeps through,
which will mostly impact QPF across the southern area of the CWA.
The aforementioned cold front will traverse the area and move east
by Monday morning, rain chances will diminish fairly quickly behind
the front, though there could be some lingering showers across NE OH
and NW PA. All in all, total QPF through the end of the event will
be around 0.60-1 inch with locally higher amounts. Flooding concerns
are minimal at this point, though there could be some minor standing
water in low lying areas. There is some chance for some low-topped
convection with this system as it moves through the region. Models
are bringing in a small amount of CAPE (~300 J/kg) in the southern-
southeastern counties during the day Sunday, so not ruling out the
chance of a rumble of thunder. In addition, there is also strong low-
level winds at 850mb between 40-50 knots. SPC continued their
Marginal Day 3 severe outlook in the southeastern counties of the
CWA, and any severe we could see associated with the thunderstorms
would be in the way of strong, gusty winds.
The surface low and associated upper level trough will continue to
push into Canada and high pressure will build into the Tennessee
River Valley through late Monday. There will be a shot at a
rain/snow mix across the higher elevations in NW PA, for a short
period of time Monday morning. Temperatures will cool slightly
Monday behind the cold front with most of the area being in the mid
40s for highs.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The next surface low will enter the region Tuesday morning as it
pushes northeast from the Ohio River Valley. This will be more
potent system in terms of impacts and changing the pattern. The
system will start as rain as it moves northeast, then change over to
a rain-snow mix for most of the area by the turn of the New Year and
then finally over to primarily snow. Strong west-northwesterly flow
will develop behind the surface low setting up for lake effect snow
across the snowbelt into the weekend. There are a few challenges
with the system; with it being nearly a week out, models are fairly
inconsistent on placement and the coverage of precipitation. There
is fairly good confidence in temperatures dropping down around
normal for early January, with highs in the low 30s and upper
20s.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
At the surface, a low moves NE'ward from southeastern IA to
central ON this evening through 00Z/Sun. This will allow a warm
front to sweep N'ward through our region between ~04Z/Sat and
~14Z/Sat. Behind the front, a ridge will nose into our area from
the Mid-Atlantic states and Carolinas. Regional surface winds
around 5 to 15 knots veer from SE'erly ahead of the warm front
to S'erly to SW'erly behind the front. Winds will gust up to 20
to 25 knots at times, especially ahead of the front and at/near
KERI.
Widespread VFR ceilings will lower to the MVFR range ahead of
the surface warm front. Behind the warm front, widespread MVFR
ceilings are expected to persist through 00Z/Sun. Scattered to
widespread rain showers are expected along and ahead of the
surface warm front. Visibility will mainly be in the VFR range,
but brief MVFR visibility is expected in steadier rain. Current
odds favor dry weather behind the surface warm front.
Outlook...Non-VFR expected with periods of rain and/or snow
Saturday night through this Wednesday.
&&
.MARINE...
Southeast winds continues through today at 10-15 knots until a warm
front lifts across the lake tonight veering the winds out of the
south. Low pressure will move northwest of Lake Erie early Saturday
and high pressure will build in to the south with lighter winds
across the lake at 5-10 knots out of the east. Sunday, another low
pressure system approaches the region and winds will strengthen to
15-20 knots across the lake out of the west, bringing high
confidence in the need for a Small Craft Advisory from late Sunday
night through Monday night from the Islands eastward. High pressure
will build in briefly and winds will weaken back down to 5-10 knots
out of the south. The next low pressure system will enter the region
on Tuesday bringing northeasterly flow across the lake. The low will
traverse the lake lake Tuesday into Wednesday and shift winds to be
west-northwesterly building to 20 knots or greater and will be the
next chance for a Small Craft Advisory.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Jaszka
SHORT TERM...Kennedy
LONG TERM...Kennedy
AVIATION...Jaszka
MARINE...Kennedy
Source:
CLE issues Area Forecast Discussion (AFD) at Dec 27, 9:12 PM EST---------------
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