NWS Marquette, MI wrote its last area forecast discussion before the first event at Feb 7, 4:32 AM EST, 28 minutes earlier.
Area forecast discussion, Feb 7, 4:32 AM EST, 28 minutes before
Area Forecast Discussion
National Weather Service Marquette MI
432 AM EST Thu Feb 7 2019
.SHORT TERM...(Today and tonight)
Issued at 431 AM EST THU FEB 7 2019
...High impact winter storm lifts north across Upper Michigan
beginning late this morning and early afternoon...
Early this morning, the weaker, lead shortwave and the onset of warm
air advection allowed for an initial push of precipitation across
the Upper Peninsula, with mostly snow being observed. Behind this
initial surge, down across Wisconsin and Minnesota light winds and
increasing moisture along a warm air advection induced surface
trough lead to areas of fog and mixed precipitation in spots.
Further downstream of the Upper Great Lakes, shortwave and low
pressure system that will bring a winter storm to the area later
today was observed currently lifting northeast across the southern
and central Plains.
After this initial round of light snow tracks across the area early
this morning, expect light snow/flurries perhaps at times mixed with
freezing drizzle ahead of the deeper moisture expected to arrive
late morning/early afternoon, with the onset of the winter storm.
Due to the light wintry precipitation expected through mid-morning,
it is possible there could be a few slick spots this morning.
Conditions will rapidly deteriorate from south to north across the
Upper Peninsula once the deeper moisture and very impressive
synoptic-scale lift arrives. What this means is the conditions that
we encounter this morning will be drastically different compared to
later today and tonight.
Now...onto the details for today/tonights winter storm. The changes
made to the forecast were to shift the main axis of heavier snow
eastward, increase the SLRs a bit out west to account for prolonged
lift through the DGZ this afternoon, and to issue a blizzard warning
tonight into Friday for Alger, N. Schoolcraft, and Luce counties (
upon collaboration with the Gaylord forecast office and long-term
forecaster). Elsewhere, the forecast still looks on track with
widespread heavy snow rapidly developing as the synoptic-scale lift
lines up over the Upper Peninsula as a potential shortwave takes on
a negative tilt as it lifts northeast this afternoon. The main
timing of the headlines look to be a bit early compared to the
latest model guidance, but given the rapid deterioration of
conditions expected late morning/early afternoon, opted to leave
start times as is. As mentioned above, out west the snow is expected
to be a bit fluffier due to the colder air wrapping around the
backside of the system, progressing eastward the SLRs will lower to
around 15:1 across the central to around 8-10:1 across the east,
with sleet likely at times out east. Storm total snowfall amounts
will range generally from 8-10'' U.P. wide, with locally higher
amounts closer to a 12''+ across the higher terrain in the Keweenaw,
north central, and portions of eastern Upper Michigan by the time
the heavier snow moves off tonight. Lesser amounts are expected near
Menominee, where 3-5'' will be possible, as the residence time of
the heavier snow will be less. As for the potential for icing or
freezing rain, it appears the main threat this afternoon will remain
south of the area as the warm nose doesn't make it this far north
with the 850mb low tracking over far south central and eastern Upper
Michigan. However, as mentioned it does look like we will see a 2-3
hour period where sleet will be possible across the south central
and east later this morning/afternoon before switching over to snow.
As the main system starts to exit the region tonight, strong and
gusty northwest winds are expected to overspread the region. Given
the steepening low-level lapse rates and winds spanning the nocturnal
boundary layer pushing 35-45kt, wind gusts upwards of 30 to 40 mph
aren't out of the question, especially east of Marquette where
northwest winds off of Lake Superior may gust even higher. Due to
this potential, blow snow with significant reductions in visibilities
will be possible, especially as we start to transition over to
smaller snowflakes with lake effect snow kicking in under the arctic
airmass moving in. Even though snow will initially be on the wetter
side, given these strong winds the top layer of the snowpack should
easily dry out. Thus, creating conditions where blowing snow as a
result of snow on the ground and falling lake effect snow will
result in whiteout conditions.
Now...onto the impacts from the winter storm. Given the strong lift,
and in some spots locally enhanced lift due to lake/terrain effects,
snowfall rates will likely approach 1-2''/hour, even locally closer
to 3''/hour in some spots. These high snowfall rates will allow
roads to quickly become snow covered, with wetter snow having a more
significant impact on travel, and visibilities to become sharply
reduced. Therefore, later today travel will become extremely
difficult, if not impossible in spots. On top of the travel impacts,
the significant snow accumulations on trees/power lines that remain
coated in ice from Monday's ice storm will lead to the enhanced
potential for tree damage and power outages this afternoon. Tonight
as the winds become northwest and gusty, the threat for power
outages and tree damage across these areas will only increase. As
mentioned above, travel will become increasingly difficult if not
impossible east of Marquette due to the strong, gusty northwest
winds tonight into Friday morning, resulting in whiteout conditions.
See the long-term forecast for details pertaining to the lingering
impacts from this winter storm.
.LONG TERM...(Friday through Wednesday)
Issued at 421 AM EST THU FEB 7 2019
With the passage of the robust low (discussed above), gusty NW winds
return and lake-effect snow showers pick back up across the northern
portions of Upper Michigan on Friday. Winds across Lake Superior
will remain blustery, ranging from 20 to 30 knots sustained, which
will likely allow for a fairly long fetch from the lake, overcoming
some of the ice buildup occurring closer to the lakeshore.
Additionally, lingering atmospheric moisture from the departing low
will help keep QPF amounts elevated with the LES, yielding around 3
to 6 inches of snow on Friday in those favored NW wind snow belt
regions, with another inch or two overnight before the winds die
down.
Stout high pressure of around 1050mb will be marching across the
Northern Plains and into the Upper Great Lakes by Saturday, which
will give the U.P. a bit of a break in the active weather pattern.
There are some indications that Upper Michigan could see a brief
round of snow traversing through Saturday night into Sunday, thanks
to mid-level convergence and a shortwave clipping by. Currently, not
too much is expected to occur as a result of this disturbance.
High pressure moves back in on Monday, with the next system to watch
arriving Tuesday. However, models are struggling to come into decent
agreement, with the 00Z GFS and ECMWF in better agreement with each
other as opposed to the Canadian. Both of the former models depict
an upper trough swinging across the Rockies, becoming negatively-
tilted, triggering cyclogenesis in the Southern Plains, and tracking
into the Great Lakes while undergoing rapid deepening (sound
familiar?). The GFS is slower and much more vigorous as compared to
its ECMWF counterpart, which means that there are quite a few
details that still need to be worked out before higher confidence
can be put into this portion of the forecast. That said, it's
concerning nonetheless as this next system could have the potential
to dump quite a bit of snow in a relatively short period of time yet
again across much of Upper Michigan. Stay tuned.
Temperatures will generally remain below normal for early February,
with highs on Friday struggling to rise above the single digits
for a large portion of the U.P. Bitterly cold temps will make an
appearance Friday night into early Saturday, bottoming out in the
negative single digits to negative teens nearly everywhere except
for the far east. If clouds are able to clear out somewhat
overnight Friday, don't be surprised if lows perhaps dip to as low
as the negative 20s in typically-cool locations. Teens and 20s
will otherwise dominate throughout the remainder of this forecast
period with lows responding accordingly.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1129 PM EST WED FEB 6 2019
With a winter system approaching from the southwest, expect VSBYs
and CIGs to quickly diminish throughout the morning peaking in the
afternoon. Expect MVFR/IFR conds thru daybreak. LIFR conditions are
expected to develop after 17Z Thur. Winds will also be on the
increase in the final hours of the TAFs with gusts approaching 20-
25kts. Slow improvement will occur at IWD and SAW Thu evening as the
heavy snow moves out.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 421 AM EST THU FEB 7 2019
Heavy Freezing Spray Warnings continue into the weekend. Gale-
force winds will impact the lake later today through tomorrow as a
deepening low pressure system tracks across the region.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Storm Warning from 10 AM EST /9 AM CST/ this morning to 7
PM EST /6 PM CST/ Friday for MIZ001>003-009-014-084.
Winter Storm Warning from 10 AM this morning to 10 PM EST this
evening for MIZ006-007-085.
Blizzard Warning from 10 PM this evening to 7 PM EST Friday for
MIZ006-007-085.
Winter Storm Warning from 10 AM this morning to 7 AM EST Friday
for MIZ004-005.
Winter Storm Warning from 10 AM EST /9 AM CST/ this morning to 1
AM EST /midnight CST/ Friday for MIZ010>013.
Lake Superior...
Heavy Freezing Spray Warning until 7 PM EST /6 PM CST/ Saturday
for LSZ162-240>244-249>251-263-264-266-267.
Gale Warning from 7 PM this evening to 1 AM EST Saturday for
LSZ245>251-265>267.
Gale Warning from 1 PM this afternoon to 1 PM EST Friday for
LSZ243-244-264.
Gale Warning from 1 PM EST /noon CST/ this afternoon to 7 AM EST
/6 AM CST/ Friday for LSZ240>242-263.
Lake Michigan...
None.
&&
SHORT TERM...Ritzman
LONG TERM...lg
AVIATION...07
MARINE...lg