Lucas and Wood Counties
fxus61 kcle 181823
area forecast discussion
national weather service cleveland oh
123 pm est mon jan 18 2021
a trough will linger over the great lakes region today and
tonight. a faster moving trough will move southeast across the
great lakes tuesday night. high pressure will build through the
area wednesday and will remain in control over the region
through thursday. another trough will move southeast through the
great lakes during the friday into saturday timeframe.
.near term /through tuesday/...
lake effect snow continues into erie county pa this afternoon,
although with a bit less intensity than earlier this morning.
will maintain the lake effect snow warnings as additional
amounts of 2 to 4 inches are possible through the end of the
warning at 1 am. totals across the region are already at 6 to 10
inches so some locations getting one foot of snow is now
expected once this round of snow is all said and done tonight.
elsewhere, snow remains fairly isolated/scattered but new
accumulations are light. another inch or two in the ne oh and nw
pa snow belts are possible through tonight. temperatures will
remain very stagnant near 30 degrees.
focus for the near term will be lake effect/enhanced snow
primarily impacting erie pa. a fairly potent snow band is
materializing offshore of ashtabula/erie counties this morning,
which right now is primarily impacting western ny. guidance
suggests this band will focus more over the northeastern part of
erie county through mid morning. although the thermodynamic
setup is marginal/fair, frictional low level convergence along
the lake/land interface will increase steadily over the next
several hours, with snowfall rates up to an inch per hour at
times. this may drop a quick 3 to 6 inches by this afternoon,
and will need to be closely monitored for locally higher amount
if the band becomes stationary for a period of time. have opted
to increase snowfall amounts and hold with the advisory, with
the higher accumulations expected to be concentrated to a small
area in the northeast part of the county. if higher amounts
become more widespread or increase in general, an upgrade to a
warning may be necessary. the convergence/forcing should weaken
a bit towards midday/early afternoon as the background flow
backs slightly, disrupting the organization of the bands with
more showery activity expected. hi-res guidance shows a strong
signal for reorganization of the bands this afternoon and
evening as the flow becomes better aligned, although some
uncertainty as to the location of the band has led to a bit more
conservative snowfall forecast for the afternoon/early evening.
have opted to extend the advisory through 1 am to cover this
potential. the bands should push into mainly western ny
overnight as the flow backs a bit further, but will be really
close to the erie shoreline overnight into tuesday, but should
disrupt and focus more into the buffalo area during the
elsewhere across the area, light snow along and northeast of a
cleveland to youngstown line will persist for a few more hours,
although any accumulations will be mainly a dusting to a few
tenths outside of the stronger lake effect band. additional snow
showers may develop this afternoon as a pv anomaly tracks east
across the area, with fairly steep low level lapse rates
developing east of the i-71 corridor. this could result in some
brief moderate snow showers, but in general snow accumulation
with this activity should be a half inch or less. mainly dry
conditions are expected outside of the lake band tonight into
tuesday, although another pv anomaly tracking across central oh
overnight into tuesday morning could bring some light snow to
the far southern portion of the forecast area. highs today will
again be in the low to mid 30s, and perhaps 1 or 2 degrees
colder on tuesday. lows tonight will be in the 20s.
.short term /tuesday night through thursday night/...
westerly flow aloft becomes northwesterly tuesday night as a
shortwave trough moves eastward over the great lakes region and the
mid to upper oh valley, and a longwave ridge begins building behind
the shortwave disturbance. at the surface, a lake-aggregate trough
begins to be replaced by a surface ridge building from the west.
steady lake effect snow (i.e. les) should settle southward across
the snowbelt as the mean low-level flow veers from westerly to west-
northwesterly and synoptic-scale low-level moisture remains abundant
in the cold air mass. periods of heavy les are possible since model
soundings indicate strong ascent may be maximized in a cloudy dgz at
times. in general, les accumulations of 1 to 4 inches are expected
in the snowbelt, but slightly greater amounts are possible in
localized areas. additional winter weather headlines may be needed.
outside the les, isolated snow showers may accompany the
aforementioned shortwave trough and amount to less than one inch.
low temperatures should reach the upper teens to mid 20`s.
on wednesday, the high pressure ridge at the surface and aloft
continues building eastward, resulting in fair weather in most of
our cwa. lingering les should shift northward across the snowbelt
and exit the snowbelt by sunset as the low-level mean flow backs
from wnw toward sw. simultaneously, the les weakens as lake-induced
cape wanes via a lowering subsidence inversion and dry air advection
in the low-levels. any additional les accumulations should be an
inch or less. daytime highs should mainly reach the mid 20`s to
fair weather is likely in our cwa wednesday night as the ridge at
the surface and aloft exits to the east and a trough at the surface
and aloft approaches from the northwest. low temperatures should
reach the upper teens to upper 20`s, with the coldest readings in
interior northwest pa. on thursday, the trough will continue
settling over the great lakes and vicinity. at the surface, a cold
front should sweep eastward across our cwa as a low moves eastward
across northern on. models continue to suggest this cold frontal
passage will primarily be dry. however, a marginally-cold air mass
and westerly mean low-level flow may allow light lake-enhanced snow
and rain showers to impact the snowbelt. little or no snow
accumulation is expected as daytime highs reach the mid 30`s to
cyclonic westerly to northwesterly flow aloft and embedded shortwave
disturbances affect our cwa thursday night as the longwave trough
persists over the great lakes and vicinity. cold air advection
allows a lake-aggregate surface trough to develop over and near the
relatively-warm lakes, including our region. lake-enhanced snow
should evolve into pure les and continue affecting the snowbelt as
mean low-level flow veers from westerly toward west-northwesterly.
snow accumulations of several inches should occur as lows reach the
mid to upper 20`s. fair weather is expected outside the lake-
.long term /friday through sunday/...
aloft, cyclonic westerly to northwesterly flow and embedded
shortwave disturbances on friday should be followed by a high
pressure ridge building from the west friday night through sunday.
at the surface, the lake-aggregate trough should persist on friday
before a building ridge begins overspreading our cwa from the west
through the rest of the long-term period. les bands should continue
downwind of lake erie friday through saturday as the mean low-level
flow of cold air veers from wnw to nnw. this les should finally end
saturday night as a lowering subsidence inversion contributes to
waning lake-induced cape. at least several inches of fresh les
accumulation are possible. odds favor fair weather outside the les
through saturday night. on sunday, widespread light snow showers are
possible as broad isentropic lift aloft may begin overspreading our
cwa ahead of an evolving low pressure system over the western and
central u.s. temperatures should be near or slightly below-normal
through the period.
.aviation /18z monday through saturday/...
widespread non-vfr continues across the region this afternoon as
a surface trough lingers near lake erie and ample low-level
moisture remains in the region behind an upper level trough.
expect mvfr to continue for most with intermittent light snow
showers as a weak shortwave aloft ripples through the region
this afternoon. in ne oh and nw pa, ifr or lower expected at
terminals where lake effect snow will continue through tuesday,
especially keri where lake effect snow has lashed the terminal
over the last 10 hours. lake snow will diminish on tuesday and
become more scattered and have improving conditions for keri for
now. winds will remain a variance of west to southwest across
the region, although some stronger gusts are possible on
tuesday, especially keri and kcle.
outlook...non-vfr possible through wednesday morning and then
again wednesday night into thursday morning. non-vfr possible
a small craft advisory is in effect from 1 pm today to 7 pm est
wednesday from willowick to ripley. in addition, a small craft
advisory is in effect from 4 pm tuesday to 7 pm est wednesday from
vermilion to willowick.
marine conditions will tend to be unsettled on lake erie through
friday as a series of troughs affect the lake. these unsettled
conditions include the expectation of westerly winds as strong as 15
to 25 knots and waves as large as 3 to 8 feet in the central and
eastern basins today through at least wednesday morning. a brief and
relative lull in winds and waves may affect the lake wednesday
afternoon and early evening in association with a high pressure
ridge. conditions should then deteriorate once again later wednesday
pa...lake effect snow warning until 1 am est tuesday for paz001-002.
marine...small craft advisory until 7 pm est wednesday for lez147>149.
small craft advisory from 4 pm tuesday to 7 pm est wednesday
Fulton and Henry Counties
fxus63 kiwx 181941
area forecast discussion
national weather service northern indiana
241 pm est mon jan 18 2021
issued at 308 am est mon jan 18 2021
sputtering snow showers by the lake may continue into the night
with a few flurries around in the early evening elsewhere, but
most areas remain dry. a cool night is in store as well as
temperatures drop into the low 20s. another round of light snow
moves in for tuesday night.
.short term...(this evening through tuesday)
issued at 233 pm est mon jan 18 2021
plenty of vorticity to work with over this period. on these westerly
trajectories, some lake enhancement continues to be indicated mainly
for our mi counties in the short range models. with a fairly large
dgz thickness and some rh to work with in there, though really only
bottom part of the dgz is moist, expect mostly snow to fall as a
result tonight into tuesday. periodic upticks in lake enhanced cape
should allow for times of sputters and starts to this lake effect
especially for a couple of hours after 00z tonight and then again
during the afternoon tuesday as a cold front slides south from mi
into the area. some riming is indicated in the dgz cross-hairs
through the period so that would keep the ratios lower. all told,
expect another 1 inch in berrien and cass counties mi and there
could be some flurries for areas away from the lake effect zones as
the sheared area of mid level vorticity works east from il. with
temperatures not expected to get above freezing until thursday,
watch out for slippery spots where snow has fallen and black ice has
formed especially during tuesday morning and up by the lake where it
has been precipitating the most. tonight`s lows fall into the 20s,
but if we do get any clearing they could edge closer to 20 degrees
instead of low to mid 20s.
.long term...(tuesday night through monday)
issued at 233 pm est mon jan 18 2021
with the upper low in eastern canada, a lobe of vorticity rounds the
base of its trough and passes by overhead tuesday night after 00z.
at the surface, a weak moisture-starved clipper-like low pressure
system is expected to pass by with coupled jets to add support and
trailing high pressure indicating cold air following the system.
this would indicate higher end slrs with 15-20:1 being most likely
for this event. sometimes these systems can pack a sneaky wintry
punch as long as there is a moisture to work with. models do show
some sort of moisture advection coming into it, but it doesn`t
really have any connection to the southern stream to work with. this
is also a pretty quick moving system and that should help to keep
snow totals on the lower end. downstream of the lake in beh, some
lake response may occur with west or slightly west northwest
trajectories, but with shallow inversion heights and some riming
indicated in the location of the omega cross-hairs, snow totals are
expected to be on the lower end. as such have some chance snow pops
in there to account for it up to 12z wed morning and another 1 inch
or so snow is not out of the question closer to the lake. have also
increased wind gusts towards 20 kts for tuesday night with some t/p
gradients to work with and mixing up to 900 mb evident on forecast
following tuesday night, more pronounced ridging moves into the
region shutting off the active period through end of the work week.
fairly strong flow across the united states will keep any low
pressure systems to our north or south and on the weaker side. our
next chance for sunshine occurs on thursday and if we can realize
that, we may be able to get temperatures into the 30s to perhaps
near 40 degrees, but again cloud cover may not allow that especially
if we can`t bring in southerly trajectories to get rid of the lake
enhanced cloud cover. we`ll have to watch the period between sunday
and early next week as a trough ejects out of the southwestern us
and enters into the airmass left behind by a cold departing 1030mb
high pressure system.
.aviation...(for the 18z tafs through 18z tuesday afternoon)
issued at 1215 pm est mon jan 18 2021
mvfr cigs to persist this period beneath low level thermal
inversion and background moist boundary layer. light snow will
taper off this afternoon. wsw winds peak around 10-15kts.
lm...small craft advisory from 9 pm this evening to 11 am est
wednesday for lmz043-046.
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Monroe and Lenawee Counties
fxus63 kdtx 182028
area forecast discussion
national weather service detroit/pontiac mi
328 pm est mon jan 18 2021
seasonably cold, moist west-northwest flow will continue to govern
conditions through tonight. a diurnal increase in lapse rates under
weak cold air advection yielding a broadening region of light snow
showers within the background of larger scale cyclonic flow.
shortwave energy noted exiting lake michigan will effectively
supplement this ascent while temporarily reinvigorating the
downstream moisture flux off lake michigan under a secondary period
of cold air advection tonight. the net effect will be a tendency for
some degree of light snow shower production to occur over roughly
the next 12 hours. if recent observational trends locally and just
upstream are any indication, then meaningful snowfall rates will
remain transient/brief thereby limiting accumulation potential
/less than an inch/.
slightly colder thermal profile in residence tuesday - 850 mb
temperatures down around -13c. brief period of mid level dry/warm
air advection will temporarily undercut the magnitude of ongoing
lake moisture flux and reduce the downstream moisture depth. this
points to dry conditions, at least early in the day. additional
shortwave energy will traverse the area during the afternoon period.
this could offer a brief synoptic increase in moisture depth,
affording a window for some inconsequential very light snow showers
or flurries to emerge within the underlying cold westerly flow. a
firm gradient and modest diurnal mixing yields a gusty afternoon
condition - in excess of 25 mph at times. highs arrive right at
seasonable levels - upper 20s to lower 30s.
stronger height falls commence tuesday night as an upper wave of
arctic origin dives into the mean trough. standard increase in
forced ascent via a combination of dcva and cold air advection will
support an increase in snow shower coverage during this time. the
general brevity of deeper layer ascent again contains accumulation
prospects - less than an inch this period. lake modified arctic air
then entrenched through the wednesday period. the existing cold west-
northwest flow again lends to some light snow shower/flurry
production, but a warming/drying profile upstream steadily
deteriorates the lake response with time.
building upper heights with an ensuing increase in warm air
advection within low level southwest flow nets a solid, albeit brief
moderating trend wed night-thursday. dry conditions maintained this
period, as greater moist isentropic resides well north.
lake enhanced moisture will continue to bring flurries to the
central great lakes this evening while snow hangs on overnight for
northern huron given the proximity to weak low pressure. winds turn
more south of west tonight with speeds increasing late. surface
pressure gradient contraction early tuesday morning will lead to an
increase in speeds throughout the day. discrepancies in modeled
upper level winds yield low-confidence for gusts to exceed 30 knots,
but there is enough support for steady 20-25 knot winds along the
thumb shoreline to produce small craft advisory waves until late
tuesday evening. a ridge of high pressure then approaches from the
midwest working to maintain higher gradient winds producing moderate
northwesterly flow across the local waters with occasional gusts in
the 25 knot range. the offshore component of the wind is expected to
keep nearshore waves below small craft criteria.
issued at 1239 pm est mon jan 18 2021
broad low pressure and moist cyclonic flow keep a healthy coverage
of lower clouds over southeast michigan this afternoon with mvfr
ceilings remaining predominant heading into this evening. a midlevel
disturbance tracks across the region this afternoon, helping to
steepen lapse rates and generate enough surface convergence to result
in an expanding coverage of snow showers for the early taf period.
the showers will be light to moderate in intensity with pockets of
ifr visibilities in any more robust activity. the passing of the
midlevel wave will lead to decreasing snow shower coverage after 00z,
but plenty of low-level moisture will remain in place with continued
mvfr conditions likely. model soundings show a deep enough layer of
saturation that light snow showers or just flurries may continue into
the overnight period, especially for locations along and north of
m-59. surface winds remain on the order of 10 kt from the wsw this
afternoon and evening.
for dtw... window for best snow shower activity remains focused on
19z to 22z with brief periods of ifr possible in any higher
intensity showers. with temps near or just above freezing,
accumulations will be limited but any more robust showers may bring
a quick dusting to a tenth of an inch. snow showers generally taper
off this evening with the brunt of any lingering showers/flurries
tracking north of dtw tonight.
dtw threshold probabilities...
* high in ceilings below 5000 feet through tonight.
* high in precip type as all snow today.
lake huron...small craft advisory from 7 am tuesday to midnight est tuesday
night for lhz421-441.
lake st clair...none.
michigan waters of lake erie...none.
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The three regional National Weather Service offices that cover the Toledo area include Cleveland, Detroit/Pontiac, and Northern Indiana.