Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 260806

Area Forecast Discussion
National Weather Service Marquette MI
406 AM EDT Wed Apr 26 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 400 PM EDT TUE APR 25 2017

WV imagery and RAP analysis indicated sw mid/upper level flow from
the srn plains to the nrn Great Lakes ahead of a trough from the
cntrl into the srn Rockies. The first of several shortwave troughs
lifting to the northeast supported a band of showers over srn MN
into sw WI. another upstream shrtwv was moving through KS. At the
surface, se winds prevailed across the cwa ahead of the a
trough/front from wrn Lake superior to the sw to low pressure ove

Tonight, expect sct shra to move into mainly the wrn half of Upper
Michigan this evening, per satellite/radar trends and short range
models. However, rain will become more widespread and heavier
overnight over the west as the KS shrtwv moves toward the area and
moisture transport and 300k-305k isentropic lift increases. 850 mb
dewpoints to around 10C and PWAT values to near 1.4 inches will
support moderate to locally heavy rain with QPF into the 0.50-0.75
inch range.

Wednesday, heavier rain will linger into the morning with additional
moderate to heavy amounts until mid level drying moves in during the
afternoon as the sfc low lifts into the area. Although the pcpn
coverage/intensity may diminish, higher POPs will continue with
sct/nmrs showers. There may be enough elevated instability over the
s and se in the afternoon for potential over isold tsra. Otherwise,
temps will climb into the upper 50s and lower 60s over the se 2/3
but remain around 40 over the west behind the slowly advancing front.

.LONG TERM...(Thursday through Tuesday)
Issued at 406 AM EDT WED APR 26 2017

Nam shows a negative tilted 500 mb trough and closed low over the
upper Mississippi River Valley 12z Thu. The closed low and 500 mb
trough slowly move northeast to James Bay by 00z Sat with more
troughing in the upper Great Lakes Fri night. Nam shows some deeper
moisture and 850-500 mb q-vector convergence on Thu. For this
forecast, used a blend of the NAM and ECMWF along with a bit of the
Canadian for Thu. This will mean a wintry mix of pcpn for Thu
morning over the western 1/3 of the cwa and will continue the
advisory through 16Z for that area with ice accumulations being the
main threat. The pcpn will pull out Thu afternoon and temperatures
will also warm enough that fzra should not be a threat. Overall, did
not make too many changes to the going forecast.

In the extended, the GFS and ECMWF show a deep 500 mb trough across
the Rockies with a closed 500 mb low near the 4 corners region 12z
Sat. The trough and upper low move into the southern plains 12z Sun
and then bring both up to the upper Great Lakes 12z Mon. ECMWF is
slower with the progression of the trough over the Great Lakes
region 12z Tue while GFS has it further northeast to the lower Great
Lakes and western Quebec area then. Upper troughing remains over the
area into Wed. Sun night into Mon could be a mix of rain and snow
with this next system and will still have to watch it as there could
some accumulating snow with this one depending on the track of it
and also the cold air.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 133 AM EDT WED APR 26 2017

A sfc trof drifting se and then stalling over Upper MI will result
in poor conditions at KIWD/KCMX/KSAW thru this fcst period under
periods of showers and considerable low-level moisture in the vcnty
of the trof. All terminals will be down to LIFR before daybreak.
While there may be some periods of IFR, expect LIFR conditions to
prevail thru this evening. Enough shallow cold air may filter into
far western Upper MI for a change to -fzra at KIWD very early this
morning and once again this evening.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 400 PM EDT TUE APR 25 2017

Northeast gales will being over west and central Lake Superior this
evening and continue through Wed evening. By late Wednesday night
into Thursday morning winds will begin to subside to 20 to 30 knots
as winds become northerly. Late Thursday through Friday, winds will
further decrease to 10 to 20 knots as winds become westerly. Winds
of 10 to 20 knots are expected through the weekend and into early
next week.

Upper Michigan...
Lake Superior...
  Gale Warning until 11 PM EDT /10 PM CDT/ this evening for LSZ162.

  Gale Warning until 3 AM EDT Thursday for LSZ264.

  Gale Warning until 2 AM EDT Thursday for LSZ263.

Lake Michigan...


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