Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 300851

Area Forecast Discussion
National Weather Service Marquette MI
451 AM EDT Thu Mar 30 2017

.SHORT TERM...(Today and tonight)
Issued at 450 AM EDT THU MAR 30 2017

Despite very dry air blo h7 on 00z GRB/APX raobs, some light
rain/trace amounts have made it into Menominee county early this
morning. Light precip is on north edge of much more organized area
of rain and even tsra running from much of IL to southern two thrids
of WI in warm/moist advection regime ahead of h5-h3 trough over
middle conus and sfc low over central MO. Upper low expected to
track to near St. Louis MO by this evening while the sfc low reaches
vcnty of Chicago IL. Light precip, mostly driven by h7 warm/moist
advection and right entrance region jet forcing, should continue to
ease into scntrl cwa this morning. ESE winds btwn the low and
exiting sfc high may also result in small chances of precip over
higher terrain of cntrl cwa. Dry air flowing in out of the high will
limit coverage and instensity of precip over all cwa. Ptype mainly
snow based on forecast soundings but a mix of rain/snow is possible
due to near sfc warm layer pushing temps into the middle or upper
30s. With plenty of cloud cover and light precip, temps should stay
in the 30s, expect over the far west with downslope flow, no precip
and potential for some thinning of mid level overcast.

Into tonight, upper low somewhat negative tilted slides to
Indianapolis IN to Louisville KY by 12z Fri while occluding sfc low
will be somewhere vcnty of Chicago IL to Detroit MI. Light precip
may try to hang on good part of night and soundings indicate that as
deeper moisture above h8 diminishes, there could be drizzle or even
freezing drizzle late over the scntrl. Otherwise, should be enough
deep moisture to keep mostly snow chances going for the east. Precip
chances for all areas will be low with the overall weak system and
since low-levels will continue to be affected by lingering dry air
tied to departing Hudson Bay sfc high pressure. Overall expected
snow totals today and tonight should be less than an inch, a bit
under latest WPC probabilties which indicated solid 1 to 2 inches
near Lk Michigan shore with potential for 4 inches over far southern
Menominee county. If most of the snow occurred during the night,
totals would be boosted slightly but daytime heating/insolation and
overall light precip intensity as offered up by latest round of
model guidance justifies keeping snowfall on the lower side of
those numbers.

.LONG TERM...(Thursday night through Wednesday)
Issued at 256 PM EDT WED MAR 29 2017

The extended looks to be fairly quiet overall with the main focus on
low pressure sliding to the south of the U.P. Thursday night and
another low pressure trough/disturbance sliding across the area
Saturday into Saturday night. Another scattered precipitation event
is possible for early next week, Tuesday into Wednesday. Otherwise,
expect above normal temperatures through the extended with highs in
the 40s to around 50 and overnight lows in the mid to upper 20s.

Thursday night: An area of low pressure sliding across the mid
Mississippi Valley is progged to lift slowly through the Ohio River
Valley through this time period. At the same time, a Hudson Bay high
pressure system will remain nearly stationary or slide very slowly
off to the east. The northern fringes of the moisture associated
with the low will try to work into the U.P.; however, the northward
extent is expected to be limited as the flow around the high
pressure system will be very dry. The easterly winds will steadily
pump dry air in to offset the approaching moisture. At this point,
will continue pushing the pops down across the south central U.P.
and east along Lake Michigan. If precipitation does occur, it will
mostly likely be in the form of light snow or rain/snow mix. Most of
the sounding looks to be below freezing with some ice crystals in
the layer; however, the lower levels are fairly dry at least through
Thursday evening. The rest of the area is only expected to see an
increase in cloud cover through this time period.

Friday through Saturday night: Drier air and a weak ridge will slide
through the area Friday into Friday night allowing for mostly clear
skies across the U.P. The next chance of maybe a few sprinkles will
be Saturday through Saturday night as a quick moving upper-level
shortwave trough slides through the area. At this point, not
expecting much in the way of precip as moisture will be limited. The
best chance of seeing the sprinles will be over the north half and
over Lake Superior.

Monday night through Wednesday: Several disturbances are progged to
slide near or through the Upper Great Lake region, giving a period
of unsettled weather. This would bring at least intermittent chances
of precipitation to the area and/or increased cloud cover through
this time period. There has been a lot of variance in the models for
this time period, as expected with it being toward the end of the
forecast period. The latest EC/Canadian have most of the area dry
through this time period, while the GFS, as the outlier, tries to
bring a system northward along with scattered rain showers. At this
point, will continue to stick with a blend of the models, painting
only marginal chance of precipitation across the area, mainly for
Tuesday into Wednesday. Stay tuned as there is still plenty of
variability in the models.

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 140 AM EDT THU MAR 30 2017

This fcst period wl be dominated by a good deal of high clds that wl
tend to thicken with time at SAW and likely lower Thu afternoon to
low end VFR and then MVFR by Thu evening. Since the low pressure
system responsible for the clds wl remain well to the s of Upr MI,
pcpn and thus lower vsbys wl tend to remain s of the TAF sites as
well. Maybe some sprinkles could be possible at SAW late Thu

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 450 AM EDT THU MAR 30 2017

Ene winds up to 20 to 25 kts are expected into Fri under the sharper
pres gradient between slowly deparing Hudson Bay hi pres and a slow
moving lo pres that will be drifting from the southern Plains toward
the Lower Great Lakes. Winds for later Fri thru Mon will be under 20
kts as a weaker pres gradient becomes established across the western
Great Lakes.

Upper Michigan...
Lake Superior...
Lake Michigan...


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