Area Forecast Discussion
Issued by NWS Marquette, MI
FXUS63 KMQT 290308 AAA
Area Forecast Discussion...UPDATED
National Weather Service Marquette MI
1008 PM EST Mon Nov 28 2016
Issued at 1006 PM EST MON NOV 28 2016
No big changes to going forecast. Widespread rain, falling moderate
to even heavy at times, will continue to lift across all of Upper
Michigan through the overnight hours. Already have seen hourly
rainfall rates at some spots over scntrl and eastern cwa up near 0.40
Does appear that there will be a rather abrupt end to the rain per
the latest high res guidance which matches upstream radar decently.
Expect the rain to end along WI border 10z (5 am ET) and around 12-
13z (7-8 am ET) near Lk Superior and over eastern cwa. Back edge of
rain has carried along with it isold tsra much of this evening.
Since edge of steeper mid level lapse rates 6.5c/km clips
southeast/east cwa as the rain ends it is possible there could be
isold tsra or at least rumble of thunder at ISQ and ERY late
tonight. Way too low of coverage to put in forecast, but it will be
interesting to see if it does occur. Approaching occluded front
extending from strong low pressure over Dakotas this evening will
sweep south to north across Upper Michigan late tonight switching
winds to more sw instead of current se direction. Could be brief
duration when dense fog could occur late tonight as rain ends, but
soundings show sharp drying all the way down to sfc. Drying along
with less favorable upslope flow should mitigate the dense fog, or
at least keep lid on long duration of dense fog.
Based on limited new model guidance and satellite and upstream obs,
brought clouds and chance of rain quickly back over west half of cwa
on Tue. Much lighter precip compared to tonight, but based on
NAM/GFS wet bulb zero heights, could see rain/snow mix over higher
terrain of west as early as late morning as the cooler air currently
over the eastern Dakotas begins to filter over WI and southwest Upper
.SHORT TERM...(This evening through Tuesday)
Issued at 413 PM EST MON NOV 28 2016
WV imagery and RAP analysis indicated a broad mid/upper level trough
over the plains with a low centered over ern North Dakota. At the
surface, a 975 mb low was located over se ND with an occluded front
looping through ern MN into cntrl IA. The combination of a shortwave
trough and strong moisture advection supported a large area of rain
over WI that was quickly spreading to the north.
Tonight, the area of strong 700-300 mb qvector supporting the
upstream pcpn over WI is expected to lift to the nne through Upper
Michigan this evening and diminish across the cwa from sw to ne
between 06z-12z. So, the area of drizzle will give way to a steadier
moderate rain. With pwat values from 0.75-0.90 inch, QPF amounts in
the 0.50-1.00 inch will be common, especially over the southeast
half. Signficant drying will then move in late over the west and
south. Temps will remain well above normal with lows in the low to
Tuesday, with the occluded front lifting to the north of the area
and qvector div and subsidence taking over, expect mainly dry
weather. Some wrap-around pcpn may sneak into the far west from nw
WI late. Otherwise, expect breezy southwest winds with temps slowly
falling into the upper 30s west. However, some sunshine over the
east half will help boost readings into the upper 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 343 PM EST MON NOV 28 2016
The low pressure system currently W of the region will weaken and
slowly meander across the area through Thu, with a couple other
waves possible coming down the back side of the system later in the
week. Colder air moves in late this week into Sat as an upper trough
moves out of NE Canada and into northern Ontario and Quebec. Early
next week is quite uncertain as models show differing solutions with
a system moving through the region.
Ptype will be driven largely by wet-bulb zero height, meaning more
snow during the night and over the higher terrain, and snow chances
will increase through the end of the week as the airmass gradually
cools. Best QPF through Sat looks to be on Thu when a shortwave
moves around the back side of the departing system and the SFC
trough swings through. However, mild SFC temps will keep precip
mixed or at least limit snowfall amounts with snow melting some as
it falls. Still some uncertainty there, but not a big concern at
Looking way out there, deterministic models are suggesting a much
colder trend beyond 10 days out, which is backed up with the CFS.
CFS also builds a large mass of very cold air across AK and the NW
Territories toward the end of Dec, which would signal a significant
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 649 PM EST MON NOV 28 2016
Low level moisture streaming into the region ahead of a deep low
pressure and frontal system will maintain the low clouds into early
Tuesday. The downslope component with the se to s flow will keep
cigs mainly in the MVFR range at IWD. However, IFR/LIFR cigs are
expected at CMX and especially SAW. Light rain will be overhead much
of the night before diminishing late tonight or around daybreak on
Tue. Fog through the night should be not as dense as the rain is
around, but if there is a break in the rain, may see a brief period
of dense fog, especially at SAW and CMX. Drier air moving into the
area behind the occluded front as winds veer sw will bring improving
conditions by mid Tue morning into early Tue aftn. For the most part
expect MVFR cigs with no vsby reduction but cigs could even
reach VFR levels at SAW.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 413 PM EST MON NOV 28 2016
Southeast gales in the tight pres gradient ahead of the deep ND low
will gradually shift off to the northeast tonight into early Tuesday.
The low pressure system will linger over the Upper Midwest Tuesday
into Wednesday. However the pressure gradient is not expected to be
as tight and should allow winds to diminish below 25kt by Tuesday
afternoon. Northerly winds to around 25 knots may develop Thursday
as the slow moving low moves to the east of Lake Superior into
Gale Warning until 10 AM EST Tuesday for LSZ249>251-266-267.
Gale Warning until 4 AM EST Tuesday for LSZ243-244-264-265.
Gale Warning until midnight EST tonight for LSZ245>248-263.
Gale Warning until 4 AM EST Tuesday for LMZ248-250.