Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 201931

Area Forecast Discussion
National Weather Service Marquette MI
331 PM EDT Sat Jul 20 2019

.SHORT TERM...(This evening through Sunday)
Issued at 146 PM EDT SAT JUL 20 2019

Subtle shortwave riding along and north of frontal boundary situated
south of our area has sustaining convective complexes and some severe
storms from southern MN into central WI today. Storms are firing along
instability gradient along and north of front where MLCAPE values
are 2000-4000 j/kg. Some of these storms evolved into a bow
echo which moved through central Wisconsin and caused
extensive wind damage across the central part of the state from Eau
Claire and La Crosse east to Appleton and Manitowoc this morning
into early afternoon. Fortunately, these damaging severe storms
have stayed south of the U.P. this afternoon.

Some lingering convection north of the main complexes and better
instability worked its way into west and south central Upper Mi
early this afternoon. CAM model trends, especially based
off the better performing ESRL HRR and NMM models, indicate some of
the light shower activity over western Upper Mi could maybe hold
together and work its way east across the rest of the cwa
this afternoon before dissipating. Have introduced slight chance
shower PoPs for this possibility. Any isolated t-storms
this afternoon should remain confined to southern portions of
Menominee County or closer to the better instability gradient but
should not be strong.

All models show any lingering showers should push off to the
se later this afternoon/early evening as sfc high pressure builds in
from the w-nw and pushes frontal boundary and associated
moisture/instability over central WI farther to the se. Sfc high
pressure in place and a push of drier, cooler air from the north
with the passage of a weak trough/cold front will result in clear
skies and a much more comfortable night tonight with min temps
expected in the 50s for most areas and perhaps even a few upper 40s
readings over the western interior.

Pleasant weather will continue into Sunday under a sfc high
pressure ridge and a light northerly flow off Lake Superior.
Under mostly sunny skies, expect highs ranging generally from the
lower to mid 70s north to upper 70s to around 80F south. Cooler mid
60s readings can be expected right along the Lake Superior shore
from Marquette eastward.

.LONG TERM...(Sunday night through Saturday)
Issued at 331 PM EDT SAT JUL 20 2019

Current upper air analysis shows a quasi-zonal flow and slight
ridging over the Great Lakes region as the jet has remained in the
same orientation over the past few days along the Dakotas through
Lake Superior into Ontario. Latest guidance continues to show this
pattern evolving as an area of high pressure builds across the
desert SW. This high will remain stationary, slowing all progression
downstream through the rest of the CONUS, and will allow a ridge to
build across the western CONUS. As the ridge builds in the west, NW
flow and trough build across the Great Lakes and east. This pattern
will hold on through Thursday this week, keeping Upper Michigan in
an extended period of dry weather, but also cooler and much more
comfortable than the last few days.

Monday, dry weather continues as an area of high pressure continues
with NW flow prevailing, perhaps a bit gusty at times. Otherwise
sunny skies and comfortable conditions with temps in the low to mid
70s and dewpoints near 50. By Tuesday, the high pressure dips down
across the Central Plains.  Temperatures will remain in the mid 70s
to perhaps 80.

On Wednesday, as the high pressure slides to the south and east,
westerly return flow will provide a little bit more punch as
temperatures climb into the low to mid 80s in the west to near 80 in
the east. Looking to the Pacific NW, our next precipitation chance
comes on shore as a shortwave begins to cross the Cascades before
reaching the Dakotas on Thursday. This shortwave begins to kick the
high pressure to the east, breaking up the pseudo-block across the
central CONUS.

Friday into Saturday, model solutions begin to converge on the
shortwave pushing across Upper Michigan. As surface temperatures
begin to reach the mid 80s again, a cold front will knock
temperatures back down for the weekend with showers and
thunderstorm chances increasing...even if it is 7 days out.

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 147 PM EDT SAT JUL 20 2019

VFR conditions are expected through the period, although KSAW and
possibly KIWD could see some isolated showers through late
afternoon. Expect light winds and clearing skies tonight under sfc
high pressure. Light lake breezes will develop at the terminals
during the day on Sunday along with potentially some diurnal cu.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 146 PM EDT SAT JUL 20 2019

Southwest to northwest winds 15 to 20 knots will veer northerly
tonight and remain so through the end of the weekend at
speeds below 20 knots. Early next week, cooler air dropping south
over Canada will allow for north-northwesterly winds between 15 and
20 knots.

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


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