624
fxus61 kcle 050537
afdcle
area forecast discussion
national weather service cleveland oh
1237 am est wed feb 5 2025
.synopsis...
high pressure will build into the great lakes tonight and early
wednesday before low pressure crosses the ohio valley wednesday
night into thursday. this low will lift a warm front through the
region thursday morning before the trailing cold front crosses
thursday evening. high pressure will return friday before
another low moves into the great lakes saturday into sunday.
&&
.near term /through today/...
900 pm est update...
still some very light/non-accumulating snow showers/flurries in
the southeastern part of the cwa, but otherwise dry weather is
anticipated for the remainder of the evening. no changes needed
with this update.
previous discussion...
a busy midweek period is still expected as a weak low pressure
system crosses the ohio valley and brings a quick shot of snow,
sleet, and freezing rain. the bulk of the impacts will occur
wednesday evening through the pre-dawn hours of thursday.
starting off this afternoon, a lingering mid/upper longwave trough
over the eastern great lakes and northeast u.s. is starting to lift
out in response to a fairly potent southern stream mid/upper
shortwave trough crossing the rockies. as the northern stream
eastern great lakes trough lifts out, one final shortwave is
dropping through the nw flow. this shortwave and associated surface
trough are crossing northern ohio and nw pa as of late afternoon,
with the associated pva and slight increase in low and mid-level
moisture supporting light lake-effect snow showers in the nw flow.
these snow showers and flurries will not amount to much more than a
trace to couple tenths in the highest elevation of nw pa. any
lingering flurries and snow showers will dissipate by mid evening as
broad surface high pressure drops into the central great lakes. this
will set up a dry and cold night with lows in the upper teens to low
20s.
the more noteworthy weather will come late wednesday into early
thursday as the aforementioned shortwave over the rockies this
afternoon crosses the mid mississippi valley wednesday afternoon and
the lower ohio valley wednesday night. this wave looks to largely
remain disconnected from the northern stream, but a 110+ knot h3 jet
streak traversing the central plains late wednesday will support a
slightly deepening surface low moving along a baroclinic zone from
the mid mississippi valley through southern ohio. this is a
favorable track for a shield of isentropic lift generated precip to
the north of the 850 mb low track, and that will be the case here as
a 30-35 knot low-level jet in the 850-925 mb layer develops
wednesday afternoon into wednesday night ahead of the wave. the lack
of phasing will keep the system moving fast, and the low-level jet
response is looking a little weaker than previous runs off the
latest nam and rap, leading to weaker mid-level moisture advection.
the isentropic ascent will generate precip starting wednesday
afternoon through wednesday night, but most signs now point to
mainly light precip.
in terms of timing and impacts, the latest href, nam, and rap
guidance suggests an initial band of light snow developing after 17z
wednesday afternoon, then gradually progressing northeastward. this
band looks to be most organized over the northern tier of counties
near lake erie through ne ohio and nw pa in the 20-23z timeframe. a
quick coating to 0.5 inches of snow is possible with this band,
slowing the afternoon commute in some areas. after 00z,
forecast soundings suggest a deepening warm nose as the low-
level jet strengthens. this will cause a larger area of
isentropic ascent precip to develop and move into the region
wednesday evening through wednesday night, and the deepening
warm nose will result in this falling as sleet and freezing
rain. the fast movement and light overall precip will keep ice
accretion from getting out of hand, but much of the area could
see 0.05 to 0.15 inches of ice, with localized amounts up to
0.20 inches. the latest href probabilities for greater than 0.10
inches of ice accretion between 12z wednesday and 12z thursday
are around 20% in most areas, with 30-40% probabilities in the
higher elevations of the central highlands and in interior ne
ohio. this gives confidence in a glaze of ice everywhere,
leading to very slick roads, walkways, bridges, and other
untreated surfaces, but most of the ice will be below the
damaging threshold. the other positive news is that warmer temps
at the surface should win out by 12z thursday, with precip
gradually changing to regular rain, so the worst of the impacts
will likely be before the morning commute.
even though this system is trending lighter, freezing rain is not
nearly as common as snow in northern ohio and nw pa, so plan a lot
of extra time to reach your destination wednesday night and thursday
morning, and exercise caution while walking outside since a layer of
black ice will be present on untreated surfaces. the ice will also
accumulate on vehicles left outside, further slowing the commute
process thursday morning. the latest ice amounts will continue
to be tweaked over the next 24 hours as the system moves in.
&&
.short term /tonight through friday night/...
the low pressure system bringing the wednesday night icing event
will depart to the east thursday afternoon taking the milder air in
the brief residence time of the warm sector with it. expecting a
decent spike in the temperatures in the far southern zones prior to
the flow turning westerly on the back side of the area of surface
low pressure, with 50f possible in these areas. at the beginning of
the short term forecast period around 12z thursday, only a small
portion of nw pa will be still prone to ice as the above freezing
air finally scours out the colder air in place, and should largely
be all rain by 15z. pressure rises commence with high pressure
building in form the northern plains region. temperatures will be
about 15 degrees cooler for friday with most areas below freezing
with the exception, again, of the far southern zones of the cwa.
meanwhile, as we head into friday night, upper level trough axis
will push through the northern rockies with an associated developing
colorado surface low that will become the main weather feature in
the long term/weekend time frame.
&&
.long term /saturday through tuesday/...
upper trough will quickly track across the northern plains and into
the great lakes with the surface low out of the colorado high plains
pushing towards lake erie/our cwa. this is going to be another
system similar to the wednesday night system from the near term
period, with overrunning of subfreezing air, transitioning
precipitation types, and another potential for ice in the forecast.
temperatures start well below freezing friday night, with the
isentropic ascent commencing after 15z saturday, an onset of
precipitation where snow/sleet/freezing rain is certainly a
potential once again, before transitioning to rain in the
southern zones with the arrival of the surface warm sector.
details will need to unfold to see if the northwester portions
of the cwa will get into the above freezing air and when, and
how long the freezing rain threat will last. the low pressure
system will move fairly quickly towards and out of the region,
so that bodes well for keeping things moving along. back around
freezing for high temperatures again for sunday and monday under
building high pressure heading into next week.
&&
.aviation /06z wednesday through sunday/...
generally vfr across the taf sites early this morning with
primarily vfr to persist through the taf period. a few pockets
of mvfr will remain possible across the eastern taf sites
through the next several hours as the lower ceilings continue to
slowly lift northwards. otherwise, main concern will be towards
the end of the taf period as a wintry mix of mainly freezing
rain and sleet arrive from the southwest. onset of precipitation
appears to be around 4 to 6z, so only going with light 6sm fzra
at this time. a brief period of heavier fzra will likely arrive
between 6 and 9z and will be reflected in the next taf update.
winds are generally out of the northeast early this morning, 5
to 10 knots. winds will gradually become out of the east today,
holding steady around 10 knots.
outlook...non-vfr expected in rain and low ceilings on thursday.
non- vfr will return in widespread rain and/or snow on saturday.
&&
.marine...
the bulk of lake erie remains ice covered, with the only significant
partially open areas being east of the islands to cleveland and then
along the immediate shoreline just past erie pa. with that said,
variable winds under 10kts tonight through early wednesday, becoming
easterly around 10-15kts wednesday night. winds then become
southwesterly 15-20kts thursday into thursday night, turning
northwesterly friday 15-20kts. could get just enough fetch east of
the islands for 2-4ft waves to avon point in the southwesterlies.
small craft advisory issuance remains suspended until further notice
due to extensive ice cover.
&&
.cle watches/warnings/advisories...
oh...none.
pa...none.
marine...none.
&&
$$
synopsis...garuckas
near term...garuckas/15
short term...26
long term...26
aviation...kahn
marine...26