FXUS63 KMQT 202314

Area Forecast Discussion
National Weather Service Marquette MI
714 PM EDT Mon May 20 2019

.SHORT TERM...(This evening through Tuesday)
Issued at 325 PM EDT MON MAY 20 2019

Remnant cold air aloft between high pressure to the west and low
pressure continuing to depart the region led to diurnal cumulus as
day-time heating increases this afternoon. Compared to yesterday,
temperatures are quite a bit warmer with early-afternoon
temperatures in the 50s inland from Lake Superior, and slightly
cooler temperatures along the shoreline.

Tonight, high pressure west of the area will track over the Upper
Peninsula, leading to a cloud-free night. Light winds and a lack of
cloud cover will allow for ample radiational cooling. Temperatures
across the interior west and central will have the potential to see
overnight lows to drop into the mid to upper 20s, elsewhere
temperatures inland from the Great Lakes are expected to be in the
low to mid 30s. Closer to Lake Superior, maritime influences will
keep temperatures in the mid to upper 30s. There is the potential we
could see fog develop across the interior west; however, with drier
air moving in confidence isn't high.

Tuesday will be a dry day as we find ourselves between high pressure
shifting east of the region and deeper-moisture advecting northward
ahead of low pressure gradually exiting the central Plains. Warmer
air aloft and diurnal heating will allow temperatures to climb into
the 60s inland from the Great Lakes, mid to upper 50s near the Great
Lakes. Over the east and central, winds will be primarily lake-
driven as the pressure gradient will be fairly relaxed. Across the
west, expect easterly winds, which may gust upwards of 12 to 18 mph
at times in the afternoon. Diurnal cumulus are expected to increase
in coverage in the afternoon, with cloud cover gradually thickening
ahead of the deeper-moisture advecting towards the region late in
the day/evening. With widespread 1-2'' of rain, locally closer to 3-
4''+ over parts of the Upper Peninsula, over the last two days and
based on partner coordination this afternoon, the fire weather
concerns have been dampened a bit, even though it will be warmer and
dry on Tuesday. Thankfully, winds also do not look terribly
impressive as the strongest gusts should be realized off to our
southwest during the day.

.LONG TERM...(Tuesday night through Monday)
Issued at 505 PM EDT MON MAY 20 2019

The upper-level pattern continues to be defined by long wave
troughing over the western CONUS through much of the extended. Ahead
of this trough models indicate a series of shortwaves lifting ne
through the Plains into the western Great Lakes region from the
middle of this week into the early part of next week bringing
periodic episodes of showers.

The first of the shortwaves to affect the Upper Great Lakes will
move through late Tue night and Wednesday as a potent closed upper
low will be pivoting through the broad western trough and lifting
northward through the the Central Plains. Strong WAA out ahead of
the shortwave and the passage of the associated sfc-850 mb warm
front will result in a period of showers from late Tue night into
Wed. The strongest 850-700 mb moisture transport will stay just
south of Upper Mi but models do indicate PWATs rising to around 1.00
inch. With marginal elevated instability of 100-200 j/kg there maybe
could be a few isolated rumbles of thunder but with showers moving
through fairly quickly not expecting the heavy rain like we saw this
past weekend. Lows Tue night around 40F will be followed by highs
Wednesday in the 50s.

The closed low from Tue night into Wed will weaken/shear
out over northern MN on Wed night and then ride across Upper Mi as
an open wave on Thursday morning/early afternoon. This could bring
more isolated to scattered showers across the area late Wed night
into Thu. This shortwave will then be followed by an amplified ridge
late Thu into Thu night and associated drier conditions. Late
Thursday sunshine should allow high temps to rise pretty close to
normal with readings in the 60s most areas, except lower 70s south
central and mid-upper 50s for Lake Superior shoreline locations in
onshore nw flow.

The pleasant weather will be short-lived, however, as another upper-
level short wave is progged to lift northeastward from the Southern
Rockies into the Northern Plains and Canadian Prairies. This system
will be tracking farther north than any of the recent systems
impacting Upper Mi which means our area will likely be well into the
synoptic scale warm sector of the low.

Models also indicate the potential for some heavy rain as ahead of
this system layer PWATs are as high as 1-1.3 inches and MUCAPE
values range from 500-1000 j/kg (highest far south central).
Initially there will be convection with the warm frontal passage and
at nose of the 45-50 kt LLJ. In addition, if the warm sector clears
enough there could be more thunderstorms developing Friday evening
and continuing Fri night along the cold frontal passage. Also, if
the GFS is correct dew points by late Friday could rise well into
the 50s and perhaps low 60s resulting in uncomfortably humid

Ridging building back in behind Friday's system should result in
fairly pleasant weather for the first couple days of the Memorial
day weekend. Inland highs both Saturday and Sunday will be in 60s
for much of the interior of Upper Mi with maybe even some low 70s
readings south central. Slightly cooler readings in the mid to upper
50s can be expected along the Lake Superior shoreline.

Looking beyond Sunday, another system approaching from the Plains
looks like it will bring another round of showers/t-storms possibly
as early as Memorial Day and continuing into Tuesday.

Many area rivers and streams are running high from record to near
record heavy rainfall over the weekend with a few bankfull or
over bankfull, warranting flood advisories or flood warnings.
Given the wet soils over the area, rivers and streams will
continue to be closely monitored through much of the week into
early next week with the threat of more rainfall.

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 714 PM EDT MON MAY 20 2019

Dry air mass associated with high pres settling over the area
tonight will allow VFR conditions to prevail thru this fcst period

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 325 PM EDT MON MAY 20 2019

Winds will continue to relax to less than 15 knots tonight as high
pressure tracks eastward over the lake. As the surface ridge vacates
the region and low pressure approaches from the southwest, east-
northeasterly winds will funnel towards Duluth across the west-half
of the lake, with wind upwards of 20 to 30 knots on Tuesday evening
into Wednesday morning. Throughout the day Wednesday, northeast
winds across the west half and southeast winds across the east half
will increase to speeds between 20 and 30 knots. Wednesday night
through Thursday, the aforementioned low pressure system will track
east across the lake, leading to varying wind directions and speeds.
Depending on the track of the system, wind speeds may change as we
get closer. Thursday night, high pressure briefly tracks east across
the Upper Great Lakes, but another low pressure system expected to
impact the region Friday into the weekend will bring another round
of elevated wind speeds from the southeast on Friday, and then from
the southwest on Saturday. Wind speeds look to range between 20 and
25 knots during this time period.

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


SHORT TERM...Ritzman
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