Area Forecast Discussion
Issued by NWS Marquette, MI

Home | Current Version | Previous Version | Text Only | 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 180703

Area Forecast Discussion
National Weather Service Marquette MI
303 AM EDT Mon Sep 18 2017

.SHORT TERM...(This evening through Monday)
Issued at 350 PM EDT SUN SEP 17 2017

...High swim risk along Lk Superior in Alger county this evening and
patchy frost late tonight interior west...

Main shortwave trough remains well to the north along with stronger
sfc low. Cold front that moved through this morning and brought the
rain and some thunderstorms late last night reaches the lower Great
Lakes on Monday while high pressure over the plains builds across
the Upper Great Lakes. Gusty northwest winds this aftn (leading to a
high swim risk on Lk Superior beaches of Alger county) will diminish
as the high moves closer tonight and with pwats down to 0.35 inches
reflecting a very dry airmass, expect strong radiational cooling for
interior areas overnight. Lows in the favored cold spots could drop
to or just above freezing so those with any sensitive plants should
cover those or bring those in if possible. High clouds increase late
tonight so that should keep far west from seeing temps drop off that

On Monday, southwest flow aloft will bring a shortwave across the
western Great Lakes region by Monday aftn. Should see a few showers
spread into the western half of the forecast area in the aftn but no
thunder is expected. After the stretch of recent late summer
weather, temps on Monday will be back down to around normal with mid
60s most areas.

.LONG TERM...(Tuesday through Sunday)
Issued at 303 AM EDT MON SEP 18 2017

Overall we will see a warming trend, with temperatures expected to
climb back up into the 80s by Friday. There will be periodic chances
for showers and thunderstorms, but confidence is highest Wednesday
night into Thursday as a cold front slowly pushes across the area.

Tuesday looks like it will be the coolest day in the extended with
near-normal temperatures as afternoon highs climb into the 60s
across the area. Cloud cover will be on the increase from the west
ahead of an approaching cold front, but expect Tuesday to remain dry
as surface ridging slowly exits the area. The warming trend will
continue Wednesday and Thursday, with high temperatures expected to
climb into the 70s. Precipitation chances will increase late on
Wednesday through Thursday as a cold front slides southeast across
Upper Michigan. Certainly looks like the instability and deep-layer
shear will be favorable for strong to possibly severe thunderstorms
later in the day on Wednesday. During the day on Thursday, the cold
front will slow its southward progress and retreat back northward as
strong warm air advection quickly returns to the area. As the front
pushes back north, a few showers and thunderstorms will be possible
through the early part of the day on Thursday.

Friday and Saturday look to be the warmest days of the week. As the
above mentioned warm air advection continues to stream northeast
across Upper Michigan, 925-850mb temperatures soar into the teens
and possible near 20 C. These warm temperatures aloft coupled with
ample downslope south-southwest winds should easily allow
temperatures to climb 10 to 20 degrees above normal for this time of
year. As we will be firmly within the warm sector, expect the
humidity to increase as well. Precipitation wise, cannot rule out a
few showers and thunderstorms associated with the return of warm air
advection and subtle shortwave activity.

Towards the end of the weekend and early next week, precipitation
chances will increase as a cold front to our west finally begins to
push eastward. Given the upper-air pattern and the general trend of
slowing the arrival of this front, wouldn`t be surprised if the
timing continues to get pushed back even further. Therefore, the
primary area of focus for precipitation is expected to be across the

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 140 AM EDT MON SEP 18 2017

Mainly VFR conditions are expected through the TAF period with high
pressure and dry air building into the region. However, a period of
shallow fog is expected that should occasionally drop vsby into the
IFR range at KSAW and KIWD overnight. A disturbance moving into
the area this evening could bring a few light showers into Upper
Michigan with mainly mid clouds.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 350 PM EDT SUN SEP 17 2017

Winds of 20-30 kts will diminish to under 20kt from w to e tonight
as sfc high pres builds into the Upper Great Lakes. With high pres
lingering on Mon, winds should be mostly under 15kt. Winds should be
under 20kt on Tue, then stronger southerly winds of 20-25kt, even up
to 30kt over eastern Lake Superior, are possible on Wed as sfc trof
moves toward the Upper Lakes. Winds will drop off to under 20kt on

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


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