Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 291120

Area Forecast Discussion
National Weather Service Marquette MI
720 AM EDT SUN MAY 29 2016

.SHORT TERM...(Today and tonight)
Issued at 412 AM EDT SUN MAY 29 2016

00Z raobs/latest wv imagery and rap analysis show shrtwv lifting
NEwd thru the Upr MS river valley. Lift associated with this
disturbance...pwats arnd 1.25 inch /150-200 pct of normal/ and axis
of a bit hier h7-5 lapse rates have triggered some showers/a few TS
over mainly wrn Upr MI closer to deeper moist air and away fm
relatively drier air shown on the 00z GRB raob. Overall though, weak
h85 theta-e advctn during period of nocturnal cooling and the
relatively dry 00z GRB raob have held down the coverage of the
showers. More isold-sct showers are present upstream fm SE MN into
NW WI in the area of DPVA ahead of shrtwv lifting to the NE. Looking
farther to the W, moist llvl air extends upstream into scentral
Canada/MN, but some drier air is present over NDakota.

Main fcst concerns this in the short term focus on expected
convection today/potential for some heavy ra.

Today...Shrtwv to the SW is progged to lift NE acrs the Western
Great Lks...reaching Ern Lk Sup by 00z Mon. Expect sct showers/a few
TS this mrng over mainly the wrn CWA to move to the E and become
more nmrs with the shrtwv forcing/accompanying sfc lo pres trof/axis
of deeper h85-5 mstr/daytime heating. Overall destabilization today
wl be limited by rather extensive cld cover and some morning fog...
with max temps topping out in the mid 70s away fm lk moderation. 00z
NAM fcst MUCape is about 1500 j/kg, but severe threat wl be limited
by 0-6km shear arnd 25 kts and deep moist lyr. The relatively weak
winds aloft/deep shear and hi pwats sug heavy ra wl be the main
threat from the stronger storms that dvlp.

Tngt...Any lingering showers/TS over mainly the ern CWA this evng wl
diminish with arrival of DNVA/Deep lyr qvector dvgc/mid lvl drying/
nocturnal cooling. The llvls are slower to dry out, but eventually
the steady WNW flow--with the 00z NAM showing h95-9 winds up to
30kts--is fcst to tap the drier air now moving E thru NDakota. The
arrival of this drier air should bring clrg to the W, but the ern
CWA wl probably remain mocldy thru 12z as the drier air is fcst to
remain to the W thru that time.

.LONG TERM...(Monday through Saturday)
Issued at 433 AM EDT SUN MAY 29 2016

A quiet end to the holiday weekend before widespread showers mid-
week and cooler weather late week.

Memorial Day: Zonal mid-level flow and surface ridging over the
Upper Great Lakes will produce mostly sunny conditions, though some
afternoon shallow and high-based cumulus will develop inland east
half in the afternoon.

Tuesday through Wednesday night: WAA ahead of troughing drifting
across the northern Plains will gradually spread clouds and precip
from west to east across the CWA. Given a somewhat dry antecedent
air mass and little additional synoptic support, have opted to
follow a slower solution for PoPs. Other than the far west, precip
should hold off until the afternoon, and possibly later for much of
the east. As the northern Plains trough moves eastward Tuesday
night, a shield of precip should spread across mainly the west half
of the CWA as a weak trough ejects out ahead of the main trough.

Expect precip to expand in coverage Wednesday afternoon and evening
as the right entrance of an upper jet lines up with the approaching
trough axis to enhance large scale forcing. 1.5 inch PWATs advecting
into the region support moderate rain for much of the CWA during
this time.

Thursday through Saturday: Continued cyclonic flow may allow for
some diurnally enhanced showers on Thursday, though inversion
heights under 5kft will likely suppress activity to nothing more than
some isolated showers or a widespread strato-cumulus deck.

Drier air and ridging will clear out the clouds by Friday. H8 temps
of 3-6C will yield afternoon highs in the 60s inland. With light
winds expected and PWATs of 0.3-0.5 inches, the cooler afternoon and
clear skies will make way for a decent night of radiational cooling
Friday night. Trended down several degrees for lows, with widespread
low to mid 40s. Some bias-corrected data shows temps falling into
the upper 30s for the interior central and east. Do not doubt that
this can occur if conditions pan out as they are currently progged
by forecast models, but did not have enough confidence to lower temps
that much five days out. Will need to keep a close eye on this as
frost may be possible inland if the aforementioned conditions pan

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 718 AM EDT SUN MAY 29 2016

With humid airmass dominating today in sly flow ahead of aprchg cold
fnt, expect lo clds to dominate the TAF sites. The poorest
LIFR/VLIFR conditions wl be at CMX, where cooling/moistening marine
influence is most pronounced. Conditions wl slowly improve with
impact of daytime heating. Aprch of a cold fnt fm the W wl bring the
threat of some showers/TS, especially at SAW where the later arrival
time of the fnt wl coincide better with the peak heating cycle. W
winds behind the fropa wl be strongest at the more exposed CMX
location, where gusts wl exceed 20 kts into this evng. The more
pronounced upslope wind component at CMX wl also result in a longer
period of MVFR cigs with only weak llvl drying not enuf to
compensate for that influence. With a weaker upslope wind at IWD and
downsloping at SAW, expect a quicker return to VFR cigs with this

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 412 AM EDT SUN MAY 29 2016

A relatively weak pres gradient/hi stability will dominate the Upper
Great Lakes most of this forecast period, so expect winds at or
below 20kts over most of the Lake. The one exception will be over
far western Lake Superior late Mon night into Tue, when the pres
gradient will tighten ahead of an approaching lo pres and terrain
funneling of the expected NE wind will cause winds up to 25 kts.
With moist air lingering over the chilly lake waters, dense fog will
persist most of today before the arrival of drier air from the W
begins to diminish gradually the intensity of the fog this afternoon
into tonight. Continued going Dense Fog Advisorys.

Upper Michigan...
Lake Superior...
  Dense Fog Advisory until 6 PM EDT this evening for LSZ243>246-

  Dense Fog Advisory until 2 PM EDT /1 PM CDT/ this afternoon for

Lake Michigan...


LONG TERM...Kluber
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