Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 250913

Area Forecast Discussion
National Weather Service Marquette MI
513 AM EDT WED MAY 25 2016

.SHORT TERM...(Today and tonight)
Issued at 358 AM EDT WED MAY 25 2016

Convection continues to pose a challenge in the short term. Pretty
quiet early this morning with fog over much of the area and some
drizzle near Lake Superior. That fog/drizzle will dissipate this
morning, allowing temps to max out in the mid to upper 70s way from
the shores of the Great Lakes.

Real challenge is with convection tonight as a shortwave moves
through the western CWA. The shortwave is currently co-located with
strong convection over Nebraska, and currently looking to move into
the west around or after 00Z tonight. Exactly how the
shortwave/convection progresses through the day will determine the
forecast for this evening and tonight. Mesoscale models are pointing
to potential for a convective complex/mesolow to move into the
western CWA, which would have potential for primarily strong to
severe winds. While highly uncertain right now, there is reasonable
potential for this to occur. MLCAPE will be 500-1000 with steep low-
mid level lapse rates. Strong moisture advection will pump PWATs of
1.5"+ into the area, which will also support heavy rain with
convection. Timing/coverage/severity will be highly dependent on
shortwave/convection progression through the day.

.LONG TERM...(Thursday through Tuesday)
Issued at 512 AM EDT WED MAY 25 2016

Southwest mid/upper level flow from the plains into the western
Great Lakes will prevail through this weekend between a mid/upper
level trough over the western CONUS and a ridge over the east.
Shortwave troughs emerging from the plains will bring rounds of
shra/tsra into the cwa. However, confidence in the the timing,
intensity and position of each of the shrtwvs is low as is typical
with patterns dominated by warm season convection. By early next
week, a more zonal but still active pattern is expected.
Temperatures will remain above normal through the period.

Thursday, Some showers and a few tsra may still linger over the
eastern cwa in the morning as a shrtwv moves away from the area. mid
level ridging and weak qvector div during the rest of the day will
be less favorable for additional tsra during the afternoon even
though temps in the lower 80s will push MLCAPE values into the 1k-2k
J/Kg range. However, some isold shra/tsra may still develop along
lake breeze boundaries.

Friday through Sunday, Higher shra/tsra chances are expected by
Friday night into Saturday as a warm front provides a focus for pcpn
along with the likelihood of shrtwvs emerging a deepening trough
over the plains. Although confidence is limited with the timing, the
models suggest that a stronger shortwave and associated surface low
will finally lift through the upper MS valley toward the northern
Great Lakes Saturday night into Sunday bringing additional shra/tsra
with slightly drier air moving in by late Sunday.

Monday and Tuesday, The models are trending toward a period of mid
level ridging may bring a respite from the pcpn with shra/tsra
chances moving back in by late Tuesday. However confidence in these
details is still marginal.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 138 AM EDT WED MAY 25 2016

The arrival of drier air aloft abv lingering llvl mstr wl result in
fog over Upr MI early this mrng, with conditions at the TAF sites
trending toward LIFR thru the ngt. There may be VLIFR conditions at
times as well especially at SAW where some heavy ra fell on Tue and
wl contribute to more llvl moistening. With daytime heating, the
fog/stratus wl grdly burn off during the mrng, bringing back a
return of VFR conditions by the aftn. More showers wl return in the
aftn ahead of an aprchg lo pres system, but VFR conditions wl
continue at the TAF sites thru the evng. Lower vsby/cigs are likely
after 06z early Thu mrng.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 358 AM EDT WED MAY 25 2016

A period of NE winds up to 25 knots is expected over the western
lake today into early tonight as low pressure develops over the
plains and moves to the Upper MS valley. There is potential for a
line of strong to severe thunderstorms to moves into the western
lake this evening or early tonight, but this is highly uncertain at
this time. Monitor thunderstorm potential closely late today into
tonight. Otherwise, expect winds at or below 20 knots through the
forecast period.

Upper Michigan...
Lake Superior...
  Dense Fog Advisory until noon EDT today for LSZ243>251-264>267.

  Dense Fog Advisory until 6 PM EDT /5 PM CDT/ this evening for

Lake Michigan...


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