Area Forecast Discussion

FXUS63 KMQT 270908

Area Forecast Discussion
National Weather Service Marquette MI
508 AM EDT Tue Jul 27 2021

.SHORT TERM...(Today and tonight)
Issued at 220 AM EDT TUE JUL 27 2021

Upper air pattern consists of a 500 mb ridge in the Rockies and 
plains with a trough over the ern U.S. this morning. There is a 
shortwave over the upper Great Lakes as well. This shortwave will 
quickly move out of the area today with the ridge building into the 
northern plains. There could still be some lake breeze convergence 
showers early this afternoon where the Lake Michigan and Lake 
Superior breezes meet up and will keep in some slight chance pops 
into that area to account for this as several models are hinting at 
this possibility. There could also be some old outflow boundaries 
from the overnight convection that combined with lake breeze 
convergence could be enough to set off some isolated showers and 
thunderstorms as well. Once this is done by evening, then quiet 
weather will set in. Did not make too many changes to the going 
forecast overall.

.LONG TERM...(Wednesday through Monday)
Issued at 507 AM EDT TUE JUL 27 2021

Models suggest the pattern will amplify as the mid/upper level ridge 
builds through western Canada and a trough deepens across the 
eastern CONUS. As a result, above normal temps Wednesday will drop 
to near or below average from Thursday through Monday along with 
relatively dry air.

Wednesday into Wednesday night, the next significant mid level 
shortwave and sfc trough is expected to move southeast through the 
region. Similar to Mon evening and early today, another batch of 
thunderstorms is expected to develop and move quickly to the 
southeast affecting portions of Upper Michigan. With forecast MLCAPE 
values into the 1000-2000 J/Kg just west of Upper Michigan and the 
CAPE boundary and mid level winds aligned more to the northwest 
to southeast, expect the strongest storms to mainly brush the far 
west and then drop southeast into Wisconsin. 0-6 Km bulk shear 
values to 50-60 knots, clusters of storms or an MCS would again 
pose a threat for damaging winds. However, some lighter shra/tsra 
could still move through much of Upper Michigan. Although the 
heavier/stronger showers/storms should move out by late evening, 
some lighter pcpn may linger overnight.

Thursday, sunshine and mild conditions are expected with high 
pressure building into the area from northwest Ontario. highs will 
climb into the low 70s north and upper 70s south. 

Fri-Sat, another clipper shortwave will dive through the region with 
additional pcpn. The GFS/GEFS/CMC was slightly faster with this 
feature compared to the ECMWF bringing the showers into the area 
late Friday night into early Saturday.

Sun-Mon, High pressure with dry weather will build into the region 
for the rest of the weekend into early next week.

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 114 AM EDT TUE JUL 27 2021

VFR conditions are expected through the period. Showers and 
thunderstorms will continue to move out early this morning.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 220 AM EDT TUE JUL 27 2021

Winds are expected to be 20 kts or less through much of the fcst 
period. A seasonably strong cold frontal passage on Thu could 
generate northwest gusts up to 20-25 knots behind the front on 
Thursday, highest over the east half.

Upper Michigan...
Lake Superior...
Lake Michigan...