Area Forecast Discussion
Issued by NWS Marquette, MI
FXUS63 KMQT 301127
Area Forecast Discussion
National Weather Service Marquette MI
727 AM EDT MON MAY 30 2016
.SHORT TERM...(Today and tonight)
Issued at 406 AM EDT MON MAY 30 2016
00Z raobs/latest wv imagery and RAP analysis show a weak shrtwv rdg
axis moving thru MN and toward Lk Sup in a zonal flow alf along the
Cndn border. Lingering clds in the wake of departing shrtwv
responsible for ydays showers/TS are just present over the ern CWA.
The 00Z INL raob is still rather moist blo mid lvl subsidence invrn
arnd h7, and there are some patchy SC/AC streaming into the wrn CWA
in the steady, slightly acyc llvl WNW flow ahead of a sfc rdg axis
in MN. The 00Z Bismarck raob shows much drier llvl air. Some patchy
fog has formed at some sheltered locations over the interior W where
winds are lighter in the presence of the lingering llvl mstr.
Looking upstream, there is another shrtwv moving E near Lk Winnipeg.
Farther to the W, a stronger shrtwv is moving E thru the nrn Rockies.
Main fcst concerns in the short term are cld trends early today and
then potential for some pcpn later tngt in advance of shrtwv moving
thru the nrn Rockies.
Today...Shrtwv rdg/Sfc hi pres/drier llvl air represented by the 00z
Bismarck raob are fcst to drift into the Upr Lks this Memorial Day.
Expect any lingering clds over the E and over the wrn CWA associated
with the moister INL raob to give way to just some diurnal cu inland
fm lk breezes. Some of the models also indicate a few showers that
form over nrn MN/adjoining Ontario on a fnt stalling acrs nrn Lk Sup
that is associated with shrtwv now near Lk Winnipeg may impact Isle
Royale later this aftn into early evng, but the llvls wl become too
dry for any pcpn over the rest of the CWA. With h85 temps fcst to
peak arnd 12C, expect hi temps to reach the mid/upr 70s away fm lk
Tonight...The 00Z NAM indicates the showers that form along stalling
fnt/axis of mid lvl fgen over nrn Lk Sup wl drift over wrn Upr MI
this evng, but prefer the pcpn-free models that hint at just some
mid clds given dryness of the llvls. Except for the NAM, the bulk of
the guidance is dry until very late, when the shrtwv now in the nrn
Rockies is progged to move into the nrn Plains. WAA/isentropic
ascent best shown on the 305K sfc /near h7/ is fcst to dvlp over the
wrn CWA late, and many of the models generate some pcpn in this area
in the 09z-12z Tue timeframe. So bumped up pops ove the wrn CWA fm
the previous fcst, which was completely dry except for far wrn Lk
Sup. With a faster incrs in cld cover, opted to raise fcst min temps
a bit, except over the E and SCentral, where skies wl be moclr
.LONG TERM...(Tuesday through Sunday)
Issued at 437 AM EDT MON MAY 30 2016
A wet mid-week is expected, with cooler conditions to follow through
the upcoming weekend.
Tuesday: A weak mid-level shortwave will eject NE across the Upper
MS Valley from a large trough drifting across the northern Plains.
This trough and an area of low-level WAA/isentropic lift across the
western CWA will produce an initial area of showers. A somewhat dry
air mass in place from today will likely limit the initial eastward
extent of this precip through a good portion of the day, with
locations east of M-95 likely remaining dry for most of the day.
Tuesday night through Wednesday night: A brief lull in precip may
occur Tuesday evening as WAA weakens and appreciable synoptic
forcing departs. Precip then increases in coverage as the main
trough axis swings NE across the area late Tuesday night into
Wednesday. Upper-level support also arrives during the day by way of
the right entrance of an upper jet streak. The trough and jet will
interact with decent low-level moisture transport to potentially
produce a couple bands of heavy rain through this period.
Thursday and Thursday night: Precip will be limited to the chance
for a few showers east on Thursday as cyclonic flow and low-level
moisture linger. Low inversions heights favor more of a widespread
strato-cumulus cloud deck than abundant shower activity, so kept
PoPs fairly low for most of the CWA. Skies clear and winds weaken as
a sfc ridge crosses the CWA Thursday night, setting the stage for
good radiational cooling as PWATs fall to around 0.5". Widespread
40s are expected, with some mid to upper 30s along with patchy frost
not out of the question for the typically coldest locations.
Friday through Sunday: Guidance has shown a dramatic shift in
solutions over the past couple days. After looking dry and quite
chilly a few model cycles ago, Friday night now looks wet as a
clipper systems dives SE into the Upper Great Lakes. The clipper
will then be absorbed into a larger trough over Quebec, setting the
stage for broad eastern Canadian troughing to develop during the
weekend. This will bring a chance or two of showers for the weekend
as weak pieces of energy rotate around the developing trough.
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 727 AM EDT MON MAY 30 2016
A steady W wind, that will be gusty at the more exposed CMX
location, will advect drier llvl air into the Upr Lks today. VFR
conditions wl thus predominate this fcst period even though mid clds
wl be on the incrs tngt at the wrn CMX/IWD sites well in advance of
a lo pres system moving thru the nrn plains. Some showers ahead of
this lo may arrive at IWD toward the end of the fcst period.
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 406 AM EDT MON MAY 30 2016
As steady W winds push drier air over Lake Superior today, expect
lingering fog to dissipate. Winds will become light this evening
with the arrival of a hi pres ridge, but as the pres gradient
tightens in advance of an approaching lo pres, ENE winds into Tue
will increase up to 25 kts over the far W, where terrain influences
accentuate this flow. As the approaching lo moves NE into Ontario on
Wed, winds will veer to the S but diminish as the pres gradient
tightens in the presence of hier stability. More widespread fog will
redevelop as the deeper S wind transports moister air over the still
chilly lake waters. After the low moves farther E and into Quebec on
Thu, winds will shift to the WNW and draw drier air back into the
area, dissipating the fog by late Thu. Lighter winds will return as
hi pres moves over the area on Fri.