Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 221949
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
349 PM EDT Wed Mar 22 2017

.SHORT TERM...(This evening through Thursday)
Issued at 348 PM EDT WED MAR 22 2017

As high pressure continued to push east across the area today, lake
effect snow showers east of Marquette diminished rapidly throughout
the late morning and early afternoon. Afternoon water vapor imagery
shows a fairly amplified pattern with a longwave trough across the
western CONUS, a ridge extending northward towards the Canadian
border and spanning much of the central CONUS, and another longwave
trough across the east. As the westernmost longwave trough slowly
continues to move east across the Rockies, a lee cyclone has begun
to develop across the northern Plains with a swath of mid-level
moisture returning northward into the northern Plains and upper
Mississippi River Valley.

As we remain under the influence of surface high pressure, expect
the pleasant weather to continue through the rest of the evening!
Late tonight into Thursday morning, as warm air advection begins to
lift across the area, expect skies to become cloudy from west to
east across the area. Overnight temperatures will be highly
dependent on how fast/thick the mid and upper level clouds come
in/will be. Confidence is highest in temperatures across the east
where cloud cover will be last to arrive and ample radiational
cooling will allow temperatures to drop into the lower teens.

As the leading edge of the warm air advection/isentropic accent
approach area from the southwest Thursday morning, expect the a band
of snow showers to develop across the western U.P. and gradually
move across the central and east through mid/late morning and
afternoon hours, respectively. Forecast soundings show ample dry low-
level air, so the initial timing for precipitation onset across the
west looks like it will occur after midnight tonight into the early
morning hours. With temperature profiles being between -10 and 0C,
do not expect the SLRs to be terribly impressive, but upwards of
half an inch of wet, slushy snow will be possible across the west
through the morning and into the central and eastern U.P. later in
the morning/afternoon. Expect the snow to transition over to rain in
locations that see temperatures climb above freezing through the
afternoon, and possibly even a break in precipitation during the day
across the west.

.LONG TERM...(Thursday through Tuesday)
Issued at 427 AM EDT WED MAR 22 2017

Nam shows a 500 mb trough in the desert sw and a ridge across the
central U.S. and a trough in New England 12z Thu. The trough moves
into the central and southern plains 12z Fri as the ridge moves into
the eastern U.S. The trough remains over the central plains through
12z Sat. Pcpn types get to be a mess this forecast period on Thu
night into Fri morning. Warm air aloft over low level temperatures
around freezing spell a problem for weather types. Cannot rule out a
sleet, freezing rain, snow and rain combo for the cwa Thu night into
Fri morning still and will continue to mention this in the hwo
product. Otherwise, did not make too many changes to the going
forecast.

In the extended, GFS and ECMWF a closed 500 mb low over the southern
plains 12z Sat with a trough in the western U.S. The closed low
heads northeast to the corn belt 12z Sun with the trough moving into
the Rockies. This trough moves out into the central plains 12z Mon.
A shortwave moves into the upper Great Lakes 12z Tue with upper
ridging moving into the area for Wed as another trough moves into
the Rockies. Temperatures look to be above normal for this forecast
period. With temperatures at night and in the early morning hours
near freezing, mixed pcpn continues to look possible and have that
in the forecast. Looks pretty active with systems moving through the
area and to the south for this forecast period.
&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 140 PM EDT WED MAR 22 2017

VFR ceilings and visibilities will prevail for the rest of the
afternoon and evening. Mid and high clouds will spread from west to
east overnight with winds becoming southerly at all terminals.
KIWD/KCMX have the potential to see a brief band of snow showers
move across the terminal Thursday morning, so have included mentions
of -SHSN along with MVFR ceilings/visibilities. Further to the east,
have opted to leave mentions of show showers out of KSAW for now as
it looks to occur towards the very end of this TAF period.
Therefore, will let subsident TAF issuance fine tune the potential
at KSAW. Otherwise, expect southerly winds to increase and become
gusty on Thursday.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 348 PM EDT WED MAR 22 2017

As high pressure continues to drop southeast of the area tonight,
winds will become southerly and increase to 15 to 25 knots by
Thursday morning. Expect the winds to increase through the afternoon
to around 25 to 30 knots. Expect s winds as hi as 30 kts, with a
few gale force gusts to 35 kts possible, on Thu evening over the
east half of Lake Superior to diminish on Thu night thru Fri as a
flatter pres gradient dominates. Expect ne veering e winds to
increase up to 25 to perhaps 30 kts on Fri night into Sun under
the tightening pres gradient between hi pres passing from Ontario
into Quebec and lo pres in the lower Great Lakes. The strongest
winds are most likely over western Lake Superior, where the lake
topography will enhance the ene flow. As these features weaken and
exit to the e, winds by Mon will diminish.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...Ritzman
LONG TERM...07
AVIATION...Ritzman
MARINE...Ritzman


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