Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190935
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
435 AM EST Fri Jan 19 2018

.SHORT TERM...(This evening through Friday)
Issued at 152 PM EST THU JAN 18 2018

Upper air pattern consists of a 500 mb shortwave moving through the
upper Great Lakes today and is replaced by shortwave ridging tonight
into Fri. Moisture is limited for this forecast period and will be
mostly sprinkles or flurries at best if they occur. Best chance for
this would be in the Keweenaw and there could be some freezing
drizzle mixed in with it. Overall, no real big changes to the going
forecast.

.LONG TERM...(Saturday through Thursday)
Issued at 435 AM EST FRI JAN 19 2018

...Impacts from potential winter storm may be delayed until later
Sun night into Tuesday...

Saturday into Sunday: The early portion of the extended forecast,
Saturday into much of Sunday looks fairly dry with models trending
slower with advance of system from the Central Plains. Actually, it
looks like high temperatures On Saturday will warm above normal with
mid to upper 30s most locations, except some lower 40s readings
possible south central. Sunday won`t be quite as warm (generally
lower to mid 30s) as winds shift northeast and clouds thicken ahead
of incoming Plains system.

Attention turns to the potential winter storm for Sunday night into
Tuesday. 00Z GFS and GEM model runs trending east and a bit slower
than 12z runs. They are now more in line with the 12z ECMWF
solution, which would track developing storm system from the Central
Plains late Sunday across northern Lower Mi Monday night. Latest 00z
ECMWF indicates even slower solution yet with dry easterly flow
around Ontario sfc high delaying pcpn arrival until at least late
Sun night. With model trend toward more eastward track across
northern Lower Mi/Mackinac Straits, this would favor snow as
predominant ptype with maybe some fzra/fzdz mixing in initially Sun
night/Mon morning until dry mid-levels moisten enough to reintroduce
ice back into cloud layer. Model suggest system would likely have
plenty of moisture to work with as southerly flow ahead of the
system wide open to tapping Gulf of Mexico moisture. Models are
still indicating upwards of an inch of qpf through the event into
Tue morning, especially over higher terrain areas favored by lake
enhancement in northeast upslope flow. With SLRs expected of 12-14/1
seems likely snowfall totals will exceed a foot over the higher
terrain of the far west (Gogebic and Ontonagon) and Baraga and
western Marquette counties of north central U.P. Model uncertainty
with this system will likely continue for the next 24 hours until
main shortwave associated with this system moves onshore of southern
CA late tonight/early Sat and can be better sampled by RAOB and sfc
observing networks. At this point, will continue to mention the
potential for widespread heavy snow late Sunday night into Tuesday
morning.

As system departs east late Tue and ridging moves behind it Tue
night into Wed, lake effect snow should taper off and become
confined to the Keweenaw and far eastern shoreline areas of cwa.
After a period of quieter wx on Thu, models suggest another system
developing over the Plains and moving into the Upper Great Lakes for
next weekend with the potential for more significant snowfall over
portions of Upper Mi.
&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1237 AM EST FRI JAN 19 2018

MVFR conditions are expected to lift to VFR at KCMX and KSAW as
drier air moves into the region. However, westerly upslope flow off
of Lake Superior may delay improvement at KCMX until later tonight.
Some fog may also be possible at KCMX but confidence is limited in
its coverage and whether it will be any lower than MVFR. LLWS is
also expected to develop from west to east Friday at KIWD and KSAW
as wrly flow increases above a strengthening inversion.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 152 PM EST THU JAN 18 2018

Gales look likely late Sun night across western Lake Superior with
northeast gales expected. North to northeast gales across Lake
Superior Mon through Tue are expected as well.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...07
LONG TERM...Voss
AVIATION...JLB
MARINE...07



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