Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KMQT 251923

Area Forecast Discussion
National Weather Service Marquette MI
323 PM EDT Sat Mar 25 2017

.SHORT TERM...(Today and tonight)
Issued at 514 AM EDT SAT MAR 25 2017

Generally quiet this morning. Upper low over central plains and
associated sfc low slowly will move toward western Illinois late
tonight. Could see some clearing in low clouds today as east low-
level winds pull in drier air with high over northern Ontario to
Quebec. Best chance of significant clearing will be over eastern
cwa closer to sfc high and due to downslope flow off Ontario. Max
temps today in the mid to upper 30s most areas. Lowest dwpnts
bottoming out around 20F over east cwa which will come into play
for ptype tonight.

Scattered rain on the northern edge of the Central Plains low will
slowly lift toward Upper Great Lakes late this aftn and more so into
this evening. Expect rain to increase in coverage and intensity as
h85 moisture transport increases/southerly h85 flow strengthens.
Upper lakes also resides within right entrance region of jet streak
over northern Ontario late tonight which will enhance the precip.
Models in decent agreement with this overall scenario. Some
difference on western extent of moderate qpf, but prefer the GEM,
GFS and EC showing heaviest qpf late tonight focusing over far east
cwa on nose of strongest moisture advection. Even though flow at h85
is strong southerly tonight allowing max wet bulb temps +4c or
higher (leading to liquid for pytpe), low level flow remains east-
northeast on flank of large high over Ontario and Quebec. Therefore,
low-levels will be dry/cold with warm air streaming in aloft.
Pattern looks favorable for freezing rain, especially over interior
east cwa closer to departing high (greater chance of lower wet bulb
temps with lower dwpnts today) and over higher terrain of ncntrl
where east wind will enhance upslope lift/cooling. Latest WPC winter
weather probabilities (consensus of various model and ensemble data)
fit this idea well with very high probabilities over 80 pct of most
cwa seeing ice accums up to 0.10 inch tonight into early Sun
morning. Highest chances of seeing 0.10 to 0.25 inch of ice (50-60
pct probabilities at this time) are focused over interior central
and east cwa. Primary freezing rain/icing hazard begins later this
evening and continues through the overnight hours.

Still a bit of time for dayshift to assess sfc temp trends today and
where heaviest rain sets up tonight as both factors will dictate
where most significant icing occurs. Thus, after coordinating with
WFOs DLH, GRB and APX, decided to let dayshift make final call on
headlines for tonight. For now, continued to mention in morning
hazardous weather outlook.

.LONG TERM...(Sunday night through Saturday)
Issued at 322 PM EDT SAT MAR 25 2017

Split flow pattern will continue across the U.S. and southern Canada
through much of the upcoming week. Once the upper level low moves
east of the Great Lakes early in the extended the weather looks
pretty seasonable and tranquil for much of the upcoming week. With
upper ridging building across the area by midweek persisting into
the later part of the work week any cold air will remain well north
of the Upper Lakes in Canada.

Any remaining precipitation should move east of the U.P. by Monday
morning as upper level system departs to the east. With low level
moisture lingering and light winds...there could be some patchy fog
through the overnight hours Sunday night.

Temperatures for upcoming week will remain around to a few degrees
above normal...upper 30s to upper 40s during the day and 20s to
lower 30s at night.  Ideal conditions for controlled snowmelt where
any snow pack remains.

Significant model differences remain for late in the week (Friday
into Saturday). ECMWF and Canadian models show a little bit more
phasing with northern and southern stream energy moving an upper low
into the Great Lakes by Friday night suggesting a rainy period from
Friday night into Saturday. The GFS maintains separate streams and
keeps a southern stream upper low over the Mid South with upper
ridging holding on across the area through Saturday yielding nice
spring weather for the area. No real confidence in either solution
and will maintain a blended approach in the forecast.

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 145 PM EDT SAT MAR 25 2017

Dry conditions and MVFR cigs expected at all sites into this
evening, through KCMX may see clouds scatter out from time to time.
A shield of precip will shift northward across Upper MI late this
evening into Sunday morning, bringing IFR cigs to all sites. FZRA is
expected at KCMX and KSAW, with ice accumulations of 0.1-0.2 inch.
Would not be surprised to see cigs reach landing mins at KSAW toward
daybreak Sunday. KIWD may remain just above freezing, so ice
accumulation will be limited. IFR clouds and MVFR vis will then
persist through Sunday morning under a stagnant air mass.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 514 AM EDT SAT MAR 25 2017

No gales expected through the period as the shipping season gets
underway on Lake Superior. East to northeast winds up to 30
knots are expected today, strongest over far western portion of
the lake as winds will funnel parallel to the shoreline into
northern Wisconsin and Minnesota. Winds become east to southeast
tonight into Sun, with the strongest winds over north central to
eastern sections. Winds for the upcoming week look to remain at 20
kts or less as high pressure settles across the region.

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


MARINE...JLA is the U.S. government's official web portal to all federal, state and local government web resources and services.