Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281926

Area Forecast Discussion
National Weather Service Marquette MI
326 PM EDT Wed Sep 28 2016

.SHORT TERM...(Today and tonight)
Issued at 440 AM EDT WED SEP 28 2016

Sfc low with nearly stacked upper low is over south central Upper
Michigan this morning, moving slowly south. ENE to NE winds are
flowing across Lk Superior to the north of the low and with water
temps across most of east half of Lk Superior upper 50s to lower 60s
(14C to 17C) and temps in lowest 5kft down to 3c, are seeing lake
enhanced rain showers which are moderate to heavy at times moving
across western and north central Upper Michigan. One automated ob in
Baraga county near Keweenaw Bay/Lk Superior shore reported nearly
quarter inch of rain within 1 hour. WV loop suggests that weak
shortwave wrapping around the upper low could be enhancing these
showers as well. Just to south of these showers, skies have been
mostly clear at times early this morning. Temps in inland portions
of scntrl cwa have been as low as lower 40s. Otherwise, readings are
in the mid 40s to mid 50s, warmest near Lk Superior.

Expect the upper low to continue southward this morning. Sfc low
moves across Lk Michigan but will generally dissolve by midday as
low over northern Ill becomes main low tied into the the upper low.
NE winds on north side of the exiting low and shortwave/q-vector
convergence with deeper moisture and similar low-level moisture and
h85 temps will continue to support lake enhanced rain showers for
west and north central this morning. Even though deep moisture
diminishes by the aftn there is abundant low-level moisture blo h8
and at least weak cyclonic low-level northeast flow. Some lighter
showers to linger all day. Certainly will see mostly cloudy skies.
Some clearing should work across eastern cwa though in wake of the
shortwave moving through this morning and as higher h7-h5 RH sinks
south this aftn. Temps stay cool over the west in the low-mid 50s. A
bit warmer in the low-mid 60s east with the increasing sunshine

Kept mention of waterspouts over northern Lk Michigan/Bay of Green
Bay this morning. Water temps over northern Lk Michigan remain in
mid 60s (18c) while beneath the upper low temps at 5kft are as low
as 2c. Delta t over 15c and effective cloud depth (EL-LCL) solidly
fit into upper low portion of Szilagi waterspout nomogram). Cluster
of showers already ongoing across northern Lk Michigan shows the low-
level convergence and following the westward movement of shortwave
that is causing these showers would point to chance of waterspouts
through the morning.

Another issue today will be high waves along Marquette and Alger
county leading to high swim risk. Since weather is expected to
improve later this morning into the aftn and water temps remain in
the low 60s, have opted to issue beach hazard statement into early
this evening.

For tonight, clouds stick around into the evening but arrival of
high pressure ridge from west and northwest will eventually bring in
drier air. Forecast soundings over inland parts of west cwa indicate
low-level moisture blo 1000 ft in the form of either fog or stratus.
May be just enough blyr wind to prohibit much fog though if inland
spots decouple there could be fog. The fog risk looks too low/patchy
right now to include. Lows will be in the 40s to the mid 50s.

.LONG TERM...(Thursday night through Wednesday)
Issued at 325 PM EDT WED SEP 28 2016

Dry wx accompanying sfc hi pres wl dominate the the beginning of the
medium range period. But as the closed lo pres responsible for the
recent pcpn lifts fm the OH River Valley back over Lower MI btwn a
deepening wrn trof and a bldg rdg off the e coast, some showers may
return as early as Sat and linger thru the weekend, especially over
se Upr MI. Any weekend showers wl give way to dry wx early next week
as another hi pres rdg dominates under a bldg upr rdg to the e of
the slow moving wrn trof. Although Thu ngt could be chilly
especially over the interior w under the initial hi pres rdg, above
normal temps should dominate the medium/extended range period.

Thu ngt...Sfc hi pres rdg axis stretching fm near James Bay into the
Upr Lks and area of mid lvl dry air to the n of nearly stnry closed
lo in the OH River Valley wl bring tranquil wx to Upr MI. Expect the
lowest min temps that may dip into the 30s at the interior cold
spots over the w under axis of lowest pwat arnd 0.5 inch/light
winds. Tended aob the lo end of guidance in this area for the lo
temps. A steadier e wind under the tighter pres gradient btwn the hi
pres rdg and the lo pres to the s as well as perhaps some hi clds
closer to the closed lo wl limit the diurnal temp fall over the se,
especially near the warming influence of Lk MI.

Fri...The closed lo to the sse is progged to move slowly to the n.
Although the deep lyr forcing associated with this disturbance wl
remain to the se, expect some incrsg hi clds as h5 hgts fall slowly.
The area from Ironwood to the Keweenaw wl see the most unfiltered
sunshine. h85 temps fcst arnd 10C wl support max temps climbing at
least near 70 away fm the moderating influence of the lks in a slowly
incrsg ene wind.

Fri ngt into Sun...As an upr trof deepens over the w and an upr rdg
blds in the wrn Atlantic Ocean, the sly wind component btwn these
larger scale features is progged to lift the closed lo back nwd and
over Lower MI. The medium range guidance is in good agreement
showing incrsg mid lvl rh but hints the most sgnft deep lyr forcing
wl tend to remain to the ese of the cwa. Since the initially dry
llvls associated with the slowly retreating sfc hi pres rdg wl have
to be overcome, suspect pcpn wl have a hard time overspreading the
area, especially the nw. Plan to go with no more than chc pops, hiest
over the se cwa closer to the closed lo center. Although the clds wl
tend to hold max temps not too far fm normal, min temps on Fri ngt
and Sat ngt should run well above avg.

Sun ngt thru Wed...The closed lo is progged to exit to the e on Sun
ngt/Mon as an upr rdg blds over the Great Lks to the e of the
deepening Rockies trof. Any lingering pcpn should diminish late on
Sun as the closed lo/mid lvl mstr exit to the e and a sfc hi pres
rdg axis to the se of Hudson Bay hi pres blds over the wrn Great
Lks. Then expect dry wx on Mon into at least Wed as the sprawling
sfc hi center blds toward New England/the Cndn Maritimes. The incrsg
sly flow btwn this hi and falling mslp in the Plains ahead of the
deep wrn trof wl advect unseasonably warm air into the Upr Lks. h85
temps are progged to reach as hi as 10-12C by Tue. Showers ahead of
the sfc lo pres/cold fnt ahead of the slow moving wrn trof may
arrive by Wed.

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 142 PM EDT WED SEP 28 2016

East to northeast winds north of departing low pressure system will
keep some showers going along with lower cigs across the area into
this afternoon. Cigs may be as low as LIFR at IWD before trending
MVFR. At CMX MVFR cigs will trend to lower VFR late this aftn.
Clouds may scatter out this evening at CMX and SAW but should stay
bkn-ovc at IWD. Overall looking at MVFR conditions tonight but could
even dip to IFR or lower at IWD. Although clouds should move out
late tonight, There is some uncertainty when the cigs will give way
to VFR at IWD Thursday morning. Otherwise, VFR conditions are
expected at CMX/SAW by late evening.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 440 AM EDT WED SEP 28 2016

Weakening low pressure will result in 20-30 kt winds today
diminishing to 20 kts or less later tonight. A general weak pressure
gradient lingering into the weekend should keep east to northeast
winds at 20 kts or less.

Upper Michigan...
  Beach Hazards Statement until 8 PM EDT this evening for MIZ005-

Lake Superior...
Lake Michigan...


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