Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190723

Area Forecast Discussion
National Weather Service Marquette MI
323 AM EDT Wed Oct 19 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 349 PM EDT TUE OCT 18 2016

Water vapor imagery and RAP analysis show wsw flow extending from
the Great Basin to western Quebec. Pair of strong shortwaves that
brought the shra/tsra and heavy rainfall to parts of Upper Michigan
last night are over Quebec, powered ene by 120kt upper jet. Shallow
moisture behind these systems and the low sun angle at this time of
year allowed low clouds to persist over much of the area this
morning. Even this aftn, it`s been a slow process clearing the
clouds with only the sw portion of the area now seeing mostly sunny
skies. A few -shra have even developed recently in Delta and sw
Schoolcraft counties where some sunshine has resulted in a little

During the short term, broad shortwave trof moving across the
western CONUS will begin to sharpen up as it moves out over the
western Plains on Wed. Meanwhile, a separate trof over Manitoba will
shift over northern Ontario on Wed as well. As these changes occur
at the mid levels, very gradual caa will drop 850mb temps that are
currently 6-7C down to around 0C over the Keweenaw to 4C over the se
fcst area by 00z Thu. With western Lake Superior water temps roughly
down to around 10c, lake effect pcpn won`t be a concern during the
short term. Couple of weak shortwaves and an associated sfc trof may
generate a few -shra or sprinkles. Given the overall weak forcing
and lack of deep moisture will leave pcpn out of the fcst. However,
there are some -shra in ND this aftn, so it`s certainly not out of
the question that there could be some -shra/sprinkles late tonight
and Wed. Temps on Wed will still be above normal over the e half of
the fcst area with highs in the upper 50s/lwr 60s. Over the far w,
highs will be around 50F into the lwr 50s.

.LONG TERM...(Thursday through Tuesday)
Issued at 323 AM EDT WED OCT 19 2016

Nam shows a 500 mb trough over the upper Great lakes 12z Thu that
digs into the ern U.S. Fri night. GFS and ECMWF show about the same
thing as well. 850 mb temperatures off the GFS and NAM over Lake
Superior drop to around -4C at 12z Thu and then fall to -4C to -6C
over Lake Superior Thu night and Fri. With lake temperatures from 9C
to 12C, this is still enough for lake effect pcpn and had to put in
some slight chance to low chance pops in to cover this into Fri
night. Overall, did not make too many changes to the going forecast
for temperatures or weather except to bump up pops a bit for lake
effect pcpn.

In the extended, GFS and ECMWF show a 500 mb ridge over the southern
plains 12z Sat with a deep 500 mb trough in the ern U.S. 850 mb
temperatures 12z Sat over Lake Superior are from -4C to -6C with
lake temperatures from 9C to 12C. This is still enough for lake
effect pcpn. A shortwave moves into the upper Great Lakes 12z Sun.
the 500 mb ridge builds into the northern plains 12z Mon and this
ridge builds into the upper Great Lakes on Tue. Temperatures will
remain near normal for this forecast period.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 121 AM EDT WED OCT 19 2016

With dry air moving into the region, expect VFR conditions through
the foreast period. There may be period of mid clouds and a few
sprinkles Wednesday as a weak cold front moves through. Winds will
also veer from w to nw with the frontal passage.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 343 PM EDT TUE OCT 18 2016

Expect winds to remain 20-25 kts or less through the rest of the
week and into the weekend as a relatively weak pressure gradient

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


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