NWS Marquette, MI wrote its last area forecast discussion before the first event at Feb 5, 12:00 PM CST, 2 hours earlier.
Area forecast discussion, Feb 5, 12:00 PM CST, 2 hours before
Area Forecast Discussion
National Weather Service Marquette MI
100 PM EST Tue Feb 5 2019
.SHORT TERM...(Today and tonight)
Issued at 301 AM EST TUE FEB 5 2019
Today:
Ongoing lake-effect snow will continue through midday, but will
shift as the winds over Lake Superior shift. Currently, the NW
wind snow belt regions are favored, but as the morning progresses,
winds across the west half of the lake will become more
northeasterly, with the east half becoming more northerly.
Therefore, look for the snow showers to follow suit, although the
snow will lighten up after sunrise, with total additional accums
(again, after sunrise) topping out at about an inch in Alger
County, and lesser amounts elsewhere within these regions. Expect
highs to top out in the teens everywhere within the U.P.
Tonight:
Weak open wave tracking from the Central Plains into the Great
Lakes later today into tonight will usher in a quick-hitting round
of snow. Upper-level jet streak traversing through will put
southern Upper Michigan in its right entrance region by later this
evening, and coupled with a vort max marching through, will be the
sources needed to provide the development of precip. Moisture will
once again be abundant, flowing in from the Gulf of California,
with an additional feed from a trough that came onshore into the
PacNW overnight. Although QPF won't be nearly as impressive as
what Upper Michigan just experienced courtesy of the ice storm,
this weak disturbance will still allow for 2-3" of snow to fall
within a 6 hour window (or less), yielding storm totals of about
3-4" this evening into the overnight hours. SLRs look to average
right around 15:1 or so, with slightly lower SLRs looking
reasonable for southern Menominee County where warmer air aloft
will be digging in from the south. Not forgetting the weight of
the ice on the trees and other structures, as well as whatever ice
remains on the ground, adding even more snow on top does not bode
well in terms of impacts. Therefore, an advisory has been issued
for the counties favored to receive the most snow with the primary
concern being travel, and the secondary concern of the
aforementioned added weight to trees, powers lines, etc. Lows
overnight will range from the single digits to lower teens area-
wide.
.LONG TERM...(Wednesday through Monday)
Issued at 343 AM EST TUE FEB 5 2019
...Potential for accumulating system snow Thursday into Friday...
The active, busy stretch of winter weather will continue through the
end of this week with a winter storm looking more likely for
Thursday/Thursday night, then lingering lake effect snow and blowing
snow to follow on Friday. Much colder air will trail behind the
exiting system, with well-below normal temperatures expected and
bitterly cold wind chills at times. However, temperatures will
return to near-normal into early next week.
Lingering snow out east will dissipate through the mid-morning
Wednesday, with the majority of any lingering snow elsewhere pushing
offshore over Lake Superior. Could see a few light snow showers
across far western Upper Michigan, but elsewhere conditions should
remain mostly dry on Wednesday.
Attention then turns to the approaching low pressure system progged
to lift northeast across the Upper Great Lakes as a potent shortwave
takes on a negative tilt lifting across the Upper Peninsula late
Wednesday night through Friday morning. Here's what we're looking at
time line wise, things appear to be slowing down a bit with multiple
rounds of light snow Wednesday night through Thursday morning
associated with broad warm air advection begins to lift across the
area. Up next, the potential for accumulating system snow Thursday
afternoon into early Friday morning across much of Upper Michigan.
There is still the potential for freezing rain across the east
Thursday afternoon into Friday morning, which is something to keep a
close eye on. Trends across the deterministic model suite, and GEFS,
have quasi-consistently taken a slower, more northerly track with
the main surface low and 850mb low, and thus warmer air aloft. Just
recently tonight, the ECMWF took quite a jog to the north with the
main surface low compared to yesterdays 00Z model guidance. Given
these trends, it certainly is not out of the question that freezing
rain may become a concern across eastern portions of Upper Michigan.
Currently, across western and central Upper Michigan, things are a
bit more complicated during this time period based on the
uncertainly in the exact track of the 850mb low and where any lake
enhancements and/or upslope flow may augment snowfall amounts.
Therefore, right now will not get into exact snowfall amounts
expected, but rather will talk impacts. With temperatures not
expected to warm above freezing ahead of this event, if the system
snow does take on wet, dense characteristics, which is very
possible, this may cause issues in spots that have lingering ice on
trees and powerlines. Travel will certainly be impacted as well;
however, as of right now the potential for heavier snow looks like
it will remain during the overnight hours Thursday into Friday. This
is certainly a time period to keep a close eye on as the details
become refined!
On Friday, a bitterly cold airmass with temperatures approaching -20
to -25C aloft will overspread the Upper Great Lakes ushering in the
return of blowing snow and lake effect snow showers, mainly across
the northwest wind snow belts. Snow accumulations should be on the
lower side as lift is displaced well above the DGZ, but expect
sharply reduced visibilities due to blowing snow and smaller
snowflakes will be likely. As for the cold, the combination of the
breezy winds and incoming cold air will make wind chill values
Friday morning feel around 20 below, and then only improving to
around 10 below during the day.
Lingering lake effect snow showers across the northwest wind snow
belts Friday night through Saturday will gradually weaken and push
offshore, expect for the Keweenaw Peninsula which may hold onto
light showers. Saturday morning will certainly be bitterly cold,
especially along the Wisconsin/Michigan border where clearing skies
are more likely and radiational cooling will allow morning
temperatures to plummet to 10 to 15 below zero. Wind chill values
Saturday morning may approach 20 to 25 below zero. Sunday into early
next week, temperatures will moderate with chances for snow near
Lake Superior, and then at times spreading across the entire Upper
Peninsula early next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 100 PM EST TUE FEB 5 2019
CMX and SAW are seeing light lake-effect snow showers this afternoon
with visbys in the IFR range for SAW. IWD is starting to see some
scattered snow showers ahead of a system that will impact all sites
later this afternoon. As this system progresses towards Upper
Michigan, expect snow at all terminals with cigs in the low-MVFR
range and visbys in IFR during the heavier snow times. A LIFR visby
at SAW is not out of the question, but confidence on where the
heaviest band of snow will set up is low. After this system pushes
through, cigs will look to improve to mid to high-end MVFR, with
visbys improving after snowfall ends.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 423 AM EST TUE FEB 5 2019
Heavy Freezing Spray Warnings continue through at least tonight
with winds generally ranging 15-20 knots sustained. Sustained
winds of 10-20 knots will prevail into Wednesday night, with winds
on the increase for the latter portion of the week. Gusts
potentially approaching gale strength may be possible on Friday as
a strong low pressure system moves across the region. Look for
winds to slacken over the weekend, generally remaining less than
15 knots sustained.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory from 4 PM EST /3 PM CST/ this afternoon
to 1 AM EST /midnight CST/ Wednesday for MIZ002-004-009-084.
Winter Weather Advisory from 7 PM this evening to 6 AM EST
Wednesday for MIZ005>007-014-085.
Winter Storm Warning from 3 PM this afternoon to 2 AM CST
Wednesday for MIZ010-011.
Winter Storm Warning from 7 PM EST /6 PM CST/ this evening to 6
AM EST /5 AM CST/ Wednesday for MIZ012-013.
Lake Superior...
Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ Wednesday
for LSZ162-240>244-249>251-263-264-266-267.
Lake Michigan...
None.
&&
SHORT TERM...lg
LONG TERM...Ritzman
AVIATION...JAW
MARINE...lg