Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 221057

Area Forecast Discussion
National Weather Service Marquette MI
657 AM EDT Sat Oct 22 2016

.SHORT TERM...(Today and tonight)
Issued at 431 AM EDT SAT OCT 22 2016

08Z Water vapor imagery shows a shortwave lobe tracking through
Ontario and the western Great Lakes region early this morning.
Although models show the deeper moisture and best dynamics (q-vector
convergence) associated with this shortwave staying generally nw of
Western Great Lakes, there is apparently enough moisture and lift to
squeeze out an isolated shower or sprinkle over Ashland WI in past

Today, Included a mention of an isolated shower over the western
counties this morning as shortwave lobe moves through the area.
Otherwise, expect dry conditions as area of warm advection mid-level
clouds spreads east across the forecast area this morning into early
afternoon and then dissipates later in the afternoon as ridging and
associated subsidence provides clearing skies from the west. Warm
advection will allow h85 temps to climb to 1C east and 4c west which
under increasing afternoon sunshine should allow for highs ranging
from the upper 40s east to upper 50s west, especially for downsloping
areas along Lake Superior.

Tonight, Weak ridging in place over the area through much of the
night will ensure mainly dry conditions. However, increasing
moisture in advance of an another shortwave/surface low approaching
from the Northern Plains will allow cloud cover to steadily increase
through the overnight hours. Temperatures will be warmer than than
Friday night due to the aforementioned increased cloud cover/WAA.
Expect lows in the mid 30s over the interior and the upper 30s to
lower 40s for locations along the Great Lakes.

.LONG TERM...(Sunday through Friday)
Issued at 342 AM EDT SAT OCT 22 2016

Upper level trough over New England and Quebec stays near stationary
into early this week while ridging aloft slowly moves from the
western Conus to the central Conus. Result will be northwest flow
aloft with seasonably cool airmass across the Great Lakes Sun-Tue.
Stronger upper level disturbance is expected to slide out of mean
trough over far western Conus early next week and this will reach the
Great Lakes by midweek as the downstream ridge lifts across Northern
Ontario to Hudson Bay. Weak shortwave moving through in the nw flow
aloft crosses on Sun. The upper level support along with associated
sfc low could bring some light rain showers across Upper Michigan on
Sun, especially from late morning into the aftn.

Behind this system a push of cooler air arrives Sun night into Mon
with h85 to h8 temps dropping to as low as -6c across eastern Lk
Superior and the eastern cwa. With Lk Superior water temps 10-13c,
resulting delta t/s 16-19c will be sufficient for lake effect
precipitation. Wbzero heights aoa 1kft should keep ptype rain.
Limited low-level convergence forecast and lack of larger scale lift
aloft should keep coverage and instensity of any lake effect on the
lower side. Best chance of measureable precip will be late Sun night
into Mon to the east of Munising. Despite nw flow across Lk Superior
appears chances for lake effect over west and north central will be
minimal due to warmer temps aloft (h85 temps only down to -2c) and
with as those areas are closer to sfc ridge/drier low-levels.

Since that sfc ridge eventually becomes main feature in low-levels
on into Tue and Wed, low pressure system crossing the central Plains
will probably experience difficulty in bringing rain farther north
into Upper Michigan by midweek but the southern portions of cwa could
see some rain on Wed into Wed night. Does not appear to be as high of
a chance as it looked previously, though model consistency here is
lacking. Only main change to forecast was to lower min temps on Tue
night over east half into the upper 20s as clouds/precip likely stay
west through daybreak on Wed.

Pretty big differences from the models by late next week and into
next weekend mainly dealing with whether upper level ridging or
troughing will be dominant and the associated warmth that makes it
to the sfc. Left the consensus alone attm with the big differences.

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 655 AM EDT SAT OCT 22 2016

VFR conditions will prevail at KIWD/KCMX/KSAW thru the forecast
period under surface high pressure.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 431 AM EDT SAT OCT 22 2016

No significant low pressure systems are expected to move through the
Upper Great Lakes in the next several days. Winds will remain below
gales through the period. A tightening gradient between a deep low
pressure system moving through Quebec and a high pressure ridge
building into the Plains could lead to a period of NW winds to 30
knots over eastern Lake Superior Sunday night into Monday.

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


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