Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 290940
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
440 AM EST Tue Nov 29 2016

.UPDATE...
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
inch/hour.

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
Michigan.
&&

.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
mid 40s.

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...(Wednesday through Monday)
Issued at 440 AM EST TUE NOV 29 2016

Wednesday into Wednesday night: The next shot of energy is progged
to slide near the eastern U.P. early Wednesday morning through
Wednesday evening. The added deep moisture along with increased
forcing, will allow for another chance of showers moving through
mainly the easter half of the U.P. Additionally, the occluded low
will begin to slide across the western U.P. by Wednesday afternoon
and directly over the U.P. Wednesday night, which will begin to
introduce precip chances over the far west in the eveing and the
rest of the U.P again overnight. By that time, cooler air will begin
to move in aloft which may allow some snow to mix in with the rain
at times over the far west late Wednesday afternoon and especially
Wednesday night.

Thursday through the Saturday: The closed low will slowly meander
east of the U.P Thursday through Friday morning before sliding out
of the area by Saturday morning and into the weekend. As this
happens, colder air will continue to filter into the region, at the
surface and aloft, allowing the rain to transition to snow.
Currently it looks like the north to northwest wind favored
snowbelts would be most likely to see the best chances for
precipitation. It does look like temperatures overall will trend
colder during this time period and 850mb temperatures are progged to
cool to the -5C to -8C range for the Thursday through Saturday
morning time period. The temps aloft may cool even more Friday night
into Saturday as a shortwave is progged to slide across the U.P.
This may act to increase the snowfall potential for the area once
again. Snow will be the primary precip type through this time period
during the overnight hours, but a mix of rain is possible along the
shoreline and east during the day.

The rest of the extended: Model solutions begin to take on large
difference, which is not atypical for looking that far out. The EC
brings a fairly strong system up across lower MI, which could have
the potential to bring stronger winds a heavy snow to portions of
the Upper Great Lakes; however, the GFS has no hint of this at all
and actually has high pressure building across the same area. With
all of the major differences will stick with a model consensus for
this time period.
&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 106 AM EST TUE NOV 29 2016

Low level moisture streaming into the region ahead of a deep low
pressure and frontal system will maintain the low clouds into early
Tue. 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 by daybreak on Tue. Could be patchy fog as
well 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 to VFR cigs with no vsby reduction at all the sites into
Tue evening.
&&

.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
Quebec.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 10 AM EST this morning for LSZ249>251-266-267.

Lake Michigan...
None.
&&

$$

UPDATE...JLA
SHORT TERM...JLB
LONG TERM...KEC
AVIATION...JLA
MARINE...JLB



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