Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 211939

Area Forecast Discussion
National Weather Service Marquette MI
239 PM EST Wed Feb 21 2018

.SHORT TERM...(This evening through Thursday)
Issued at 239 PM EST WED FEB 21 2018

Overall, quiet weather has begun to settled in for the
next 24 hours across Upper Michigan. Lingering light lake effect
snow showers across the west to northwest wind snow belts has
gradually diminished this afternoon as surface ridging began to lift
northeast. Ample sunshine was observed across much of western and
central Upper Michigan, where temperatures quickly rebounded into
the upper teens and 20s through the afternoon hours.

The main forecast concern over the next 24 hours are temperatures.
Tonight, surface ridging will continue to track northeast across
Upper Michigan. The resulting drier air mass, clear skies, and light
winds will give way to ample radiational cooling across the area.
Not terribly impressed with how guidance seems to be handling the
potential for colder temperatures tonight, so did make manual
adjustments to lower temperatures down below zero across
the interior west and central. Elsewhere, temperatures should easily
drop into the single digits. Thankfully, winds will be
light tonight so there will be no wind chill concerns. Thursday,
warm air advection will begin to gradually lift northward with
thickening cloud cover during the afternoon. Temperatures will warm a
few more degrees compared to today as a result, with highs climbing
into the upper 20s to lower 30s. Snow chances will hold off until
Thursday night, when the next system is progged to track across the
region - see the latest long term discussion for further details.

.LONG TERM...(Thursday through Tuesday)
Issued at 244 AM EST WED FEB 21 2018

Nam shows a 500 mb trough in the western U.S. with a ridge in the
sern U.S. 12z Thu. A shortwave ejects out of this trough and heads
northeast towards the upper Great Lakes 12z Fri. The trough moves
moves into the Rockies and northern plains 12z Sat. Nam brings in
some deeper moisture and 850-500 mb q-vector convergence late Thu
night and both move out late Fri morning. Still looks like there
could be a wintry mix of pcpn on Fri morning with the highest pops
then. Overall, did not make too many changes to the going forecast.

In the extended, GFS and ECMWF show a 500 mb trough in the Rockies
and northern plains 12z Sat. This trough heads northeast into the
upper Great Lakes 12z Sun. 18z GFS has a 971 mb low near the U.P.
while the 00z GFS run has a 976 mb low 12z Sun. The 12z ECMWF has a
weaker low of 1004 mb 12z Sun. More upper troughing moves in for 12z
Mon. Troughing moves into the western U.S. on Tue and Wed and pushes
up a ridge into the ern U.S. Temperatures stay above normal for this
forecast period. System for Sat night into Sun continues to bear
watching with the differences in strength between models.

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1222 PM EST WED FEB 21 2018

Once lingering MVFR ceilings and lake effect snow showers dissipate
early this afternoon, VFR ceilings and visibilities are expected
through the rest of this TAF period. Tonight, winds will become
light as high pressure tracks across Upper Michigan.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 239 PM EST WED FEB 21 2018

20 to 30 knot winds over Lake Superior will relax to less than 20
knots by Thursday morning as high pressure lifts across the region.
Expect winds to remain below 20 knots through much of Saturday. A
strengthening low pressure system is progged to track across the
Upper Great Lakes later this weekend; therefore, expect winds to
ramp up to between 20 to 30 knots.

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


SHORT TERM...Ritzman
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