Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 201957

Area Forecast Discussion
National Weather Service Marquette MI
357 PM EDT SAT AUG 20 2016

.SHORT TERM...(Today and tonight)
Issued at 646 AM EDT SAT AUG 20 2016

The 5H trough continues to dig into the northern plains this morning
per the latest satellite WV imagery. Additional energy moving into
the backside of this feature will help enhance the surface low
currently over the central Mississippi Valley, with this low
deepening as it moves into northeast WI and eastern Upper Michigan
during the day. The low will then shift northeast out of the region
overnight while high pressure builds into the central plains.

Multiple forecast challenges exist in the short term due to the
track and strength of the surface low. There will be plenty of rain
associated with this system especially across the central and east
as those areas showing 1.5-2 inches PW per latest Bufkit soundings.
And while instability is rather low, a weak vort max lifting through
the area along with the right entrance region of the 3H jet passing
by should be enough to help bring some of the thunderstorm activity
over WI into central and eastern Upper Michigan this afternoon,
especially if there is a break in the cloud cover there due to some
slight mid-level drying as shown on satellite. Winds will be quite
gusty once the low passes through the area but the main impacts will
be over the marine zones. Still, exposed areas along the Superior
lakeshore east of Marquette and along the higher terrain of the
Keweenaw may see occasional gusts up to 40 mph. temperatures for
today will also be slightly challenging as if there is a brief break
in the sky cover over the east, temperatures there could rise a
little higher than currently expected. Weak cold air advection over
the west along with plenty of sky cover to help keep lows there
below seasonal averages.

.LONG TERM...(Sunday night through Saturday)
Issued at 356 PM EDT SAT AUG 20 2016

Sunday Night: Expect a more settled pattern as we start next week as
WNW flow takes hold across the north-central CONUS. Better moisture
will depart and the pressure gradient will lax heading into Sunday
night, allowing for a good radiational cooling set-up across much of
the CWA. Other than a few lingering light showers or strato-cumulus
across the NE in the evening, expect mostly clear skies through the
night. Continued to favor the lower end of guidance for min temps,
with low 40s expected across portions of the interior.

Monday and Tuesday: Increasing WAA on Monday will support isolated
showers/storms to the north of the CWA. Capping will prevent precip
initiation away from Lake Superior and possibly the Keweenaw
Peninsula during the day. However, the nose of a strengthening LLJ
ahead of an approaching sfc low over the northern Plains may induce
some elevated convection Monday night. Dry and warm conditions are
then expected for Sunday, with highs pushing well into the 80s
amidst gusty SW winds.

Wednesday through Saturday: Phasing of a cluster of troughs will
occur across the region Wednesday into Thursday while the a pair of
upper jet axes cross the area. Forcing becomes a bit muddled given
the interactions between all of these synoptic features, but best
chances for showers and possibly some thunderstorms will be Wednesday
afternoon as a sfc trough traverses the CWA. With several convective
parameters far from ideal Wednesday afternoon, no strong to severe
storms are expected at this time.

Surface high pressure and upper ridging will then bring dry and
mostly clear conditions Friday into early Saturday before a rather
open mid-level wave induces mainly showers to close out the weekend.

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 136 PM EDT SAT AUG 20 2016

With deepening low pres over ne WI crossing eastern Lake Superior
tonight, shra will continue. To the w of the low track, upslope
winds off Lake Superior should result in prevailing LIFR conditions
at KSAW into the evening hrs. KCMX should drop to IFR in the next
few hrs, but confidence is not especially high as northerly winds
will not be the ideal upslope direction for that terminal. KIWD
should see prevailing IFR conditions under a better upslope wind
direction. Overnight into Sun morning, expect gradual improvement
from w to e. KIWD/KCMX should break out to VFR around 12Z. At KSAW,
expect MVFR conditions to develop late tonight, but VFR may not
develop until near or just beyond this fcst period. Finally, closer
to the low pres track, gusty winds will impact KCMX/KSAW for much of
this fcst period with gusts as high as 30kt at times tonight.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 411 AM EDT SAT AUG 20 2016

A low pressure system, rapidly developing along the cold front
stretching across the central U.P. into Wisconsin, will track from SW
WI this morning, to near Green Bay this evening. The low will the
shift east of Sault Ste. Marie by Sunday morning. In response, NE
winds will increase to 25 knots through this afternoon. After the low
passes this evening, N to NNW gales to 40 knots are expected to
develop across the east half of Lake Superior. There could also be
some storm force gusts as high as 50 knots over south central and
eastern Lake Superior late tonight into early Sunday morning. As high
pressure then slowly builds in from the west through Monday, NW winds
will gradually diminish from around 30 knots Sunday morning to less
than 15 knots by Monday morning. A period of southerly winds of 10 to
20 knots is then expected Tuesday into Wednesday as the high pressure
drifts to the SE and low pressure develops over south-central Canada.

Upper Michigan...
  Beach Hazards Statement until 10 PM EDT this evening for MIZ005-

Lake Superior...
  Gale Warning from 3 AM to 2 PM EDT Sunday for LSZ251-267.

  Gale Warning from 8 PM this evening to 2 PM EDT Sunday for

  Gale Warning from 8 PM this evening to 8 AM EDT Sunday for

  Gale Warning from 2 AM to noon EDT Sunday for LSZ250.

Lake Michigan...
  Gale Warning from 11 PM this evening to 11 AM EDT Sunday for



LONG TERM...Kluber
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