Winter Storm in Michigan, January 28, 2019

Area Forecast Discussion
National Weather Service Grand Rapids MI
1101 PM EST Sun Jan 27 2019

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 316 PM EST Sun Jan 27 2019

- Moderate to heavy snow will develop late tonight and continue
  Monday. Total accumulations in the 8 to 12 inch range north
  of I-96 and 4 to 8 inch range south of I-96 are expected.

- Dangerously cold air will move over the state Tuesday and air
  temperatures will struggle to reach 0 Wednesday.

- Apparent temperatures (wind chills) will fall to -25 to -35
  Tuesday night through Wednesday night.

&&

.UPDATE...
Issued at 947 PM EST Sun Jan 27 2019

Based on radar...observations and latest model data we delayed the
onset of the heavier snow tonight and lower the overnight
accumulations with this update. We did bump up the amounts for
Monday so the overall storm total amounts did not change much. We
are still looking at an impactful storm rolling in later tonight
and more so on Monday. The combination of inch per hour
rates...wind and very low wind chills will all combine to lead to
the hazard. There is even some weakness in the stability showing
up in the guidance which will help support the higher snow rates.
Guidance is somewhat variable on the strength of the winds later
tonight and on Monday...but confident is rather high on gusts
topping 30 mph. I does look like the direction will be shifting
considerably since the storm tracks eastward right through the
CWA Monday into Tuesday.

&&

.DISCUSSION...(This evening through next Sunday)
Issued at 316 PM EST Sun Jan 27 2019

The forecast of heavy snow and brutally cold air is largely on
track. 12z models continue to show 8 to 12 inches of snow north of I-
96 and 4 to 8 inches south of I-96 Tuesday. One of the potential
problems with this forecast though is that the 3km NAM has been
slowing down the onset of snowfall an hour or two per model run and
now doesn't show snow developing until closer to 10z at the lake
shore. If that's actually the case, snow won't begin in Lansing
until 7am or so. We're still leaning on an earlier start time mainly
because the GEM, ECMWF, and GFS continue to show snow developing at
the lake shore by 08z or so. As such, we'll continue with our going
accumulation forecast and time line.

From a travel impact standpoint, the key to this is knowing that
even if the snow starts a little later, it's still going to get here
during the day and accumulate as noted above and travel will be
seriously degraded as the day progresses.

East wind gusting to 20-25 mph will result in blowing snow/drifting
too especially on north/south roads such as US-131 and US-27.
Visibilities will fall well below a mile at times.

Arctic air will begin to flow in behind the low Monday night and
highs Tuesday will only be in the teens. By Tuesday night, h8
temperatures fall to -34c over the southern cwa. Apparent
temperatures will plummet to -30 to -35 by Wednesday morning and
Thursday morning and highs Wednesday will be in the 0 to 5 below
range. Lows Tuesday night and Wednesday night will be in the -8 to -
15 range.

A warm up will then begin and temperatures will rise to the teens
Friday and 30s by Saturday and near 40 by Sunday. The next system
may actually produce some rain late in the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1100 PM EST Sun Jan 27 2019

A high impact winter storm will impact all TAF sites during the
forecast period. The main forecast elements relevant to the TAF
sites are as follows:

- Confidence is high that all TAF sites will experience visibility
  at or below 1/2SM from roughly sunrise through mid- morning due
  to moderate to heavy and blowing snow. Visibility may drop below
  1/4SM at times in heavier snow bands, but will defer to
  amendments to introduce such low visibilities when locations of
  bands become apparent. Snow intensity is expected to gradually
  decrease during the afternoon hours, first at AZO/BTL/JXN and
  then at MKG/LAN/GRR. However, blowing snow may remain an issue
  through the entire TAF period.

- Winds will start easterly at all TAF sites and gust upwards of
  25-30 kts. Winds will veer southeasterly and eventually
  southwesterly at AZO/BTL/JXN by early afternoon as a warm front
  lifts through Lower Michigan. At GRR/LAN, winds will also likely
  veer southerly to southwesterly toward 21Z/4PM, though it is
  possible that winds remain easterly through daylight hours.
  Winds will then turn northwesterly at all TAF sites after dark,
  all the while gusting in the 20-30 kts through the entire TAF
  period. Higher gusts are possible at MKG, especially after dark.

- Lake effect snow and blowing snow may impact MKG/AZO/BTL toward
  the very end of the TAF period. For now, we will carry 3SM
  visibility though lower values are likely to be introduced in
  later TAF packages.

&&

.HYDROLOGY...
Issued at 316 PM EST Sun Jan 27 2019

An ice jam has formed on the Muskegon River downriver from Bridgeton
in Newaygo County. Only minor flooding is occurring. Ice growth is
up on our rivers and most should be covered over by next weekend.
With the thickening ice, many streams and rivers will remain covered
through any future short-lived warmups. The threat of ice jams
continues into next week, primarily along any sections of river that
are still in the process of freezing up. Ice jams can cause rapid
changes in water levels, so anyone living or recreating near one of
our rivers should pay extra attention to conditions over the next
week.

&&

.CLIMATE...
Issued at 316 PM EST Sun Jan 27 2019

Here are the record low maximum and minimum temperatures for next
week starting Tuesday and ending Saturday.

Grand Rapids

1/29...7 in 1934, -16 in 1966
1/30...4 in 1899, -22 in 1951
1/31...4 in 1971, -20 in 1899
2/1....5 in 1971, -20 in 1899
2/2....2 in 1996, -11 in 1971

Lansing

1/29...6 in 1965, -28 in 1867
1/30...5 in 1899, -22 in 1867
1/31...5 in 1971, -14 in 1899
2/1....5 in 1966, -16 in 1918
2/2....4 in 1996, -37 in 1868

Muskegon

1/29...2 in 1899, -12 in 1966
1/30...6 in 1966,  -6 in 1994
1/31...3 in 1971, -11 in 1918
2/1....3 in 1971, -22 in 1918
2/2....0 in 1996, -10 in 1985

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 7 PM EST Monday for MIZ064>067-
071>074.

Winter Storm Warning until 7 PM EST Monday for MIZ037>040-
043>046-050>052-056>059.

&&

UPDATE...MJS
SYNOPSIS...04
DISCUSSION...04
AVIATION...Borchardt
HYDROLOGY...63
CLIMATE...04

Hazardous Weather Outlook
National Weather Service Grand Rapids MI
330 PM EST Sun Jan 27 2019

LMZ844>849-MIZ037>040-043>046-050>052-056>059-064>067-071>074-
280830-
St Joseph to South Haven MI-South Haven to Holland MI-
Holland to Grand Haven MI-Grand Haven to Whitehall MI-
Whitehall to Pentwater MI-Pentwater to Manistee MI-Mason-Lake-
Osceola-Clare-Oceana-Newaygo-Mecosta-Isabella-Muskegon-Montcalm-
Gratiot-Ottawa-Kent-Ionia-Clinton-Allegan-Barry-Eaton-Ingham-
Van Buren-Kalamazoo-Calhoun-Jackson-
330 PM EST Sun Jan 27 2019

This hazardous weather outlook is for portions of southwest Lower
Michigan.

.DAY ONE...Tonight

Snow will develop along the lake shore by 3 am and spready east.
Several inches accumulation is expected by sunrise.

Apparent temperatures of 10 to 20 below zero are expected tonight
mainly across northern interior sections of Lower Michigan.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Multi-day delays, cancellations, or closures are likely this week
due to high-impact winter weather.

- A snowstorm will deliver 4-8" (8-12") south (north) of I-96 Monday
  with significant impacts to travel. Blowing snow and decreasing
  temperatures will make snow removal and recovery efforts
  difficult, especially north of I-96.

- A dangerous cold outbreak and additional lake effect snow
  showers will lead to dangerous to life threatening conditions
  Tuesday night through early Thursday morning. Apparent
  temperatures as low as 25 to 35 below zero are possible
  Tuesday night through Wednesday night. The lake effect snow
  will lead to low visibility, especially along the lake shore.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed; however, spotters are
encouraged to relay snowfall reports to the National Weather
Service office in Grand Rapids over the coming days.