539 
FXUS63 KMQT 040926
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
526 AM EDT Sun Apr 4 2021

.SHORT TERM...(Today and tonight)
Issued at 505 AM EDT SUN APR 4 2021

Water vapor imagery and RAP analysis show a broad mid-level ridge 
covering much of the west and central Lower 48. As a result, wnw 
flow currently prevails across Upper MI. WAA/isentropic ascent 
regime in response to a weak shortwave over ND is leading to high 
and mid cloudiness spreading ese into Upper MI early this morning. 
There have been a few weak radar returns noted within the cloud 
deck, but very dry air blo 700mb as sampled on the 00z KINL sounding 
indicates no pcpn will reach the ground. With the dry air mass and 
little no wind under sfc high pres ridge, temps have fallen into the 
upper 20s/lwr 30s F across much of the fcst area. A few spots have 
settled into the mid 20s across the eastern fcst area. 

Fire wx will again be the concern today. Although waa/isentropic 
ascent spreading across the area will lead to quite a bit of mid and 
high cloudiness thru the day, fcst soundings still indicate very dry 
air lingering in the lower levels. Building of the mixed layer won't 
lead to sharply lowering dwpts during the day like it did yesterday 
over western Upper MI since the dry air aloft today is not nearly as 
substantial as yesterday. Nonetheless, it will either help maintain 
low dwpts thru the day or lead to some modest lowering of dwpts. 
Despite the mid/high clouds, temps in general should top out from 
the mid 50s e to mid 60s F w. E to se winds will lead to cooler 
conditions close the Great Lakes where these winds have an onshore 
component. With the expected high temperatures and dwpts generally 
ranging thru the 20s F, RH should bottom out roughly from 17 to 27 
percent w half to 28 to 38 percent e half. Increasing pres gradient 
btwn high pres shifting e of the area and low pres trof approaching 
the Upper Mississippi Valley will lead to se wind gusts of 15-20mph 
today across generally the w half of Upper MI. Thus, for the 3rd day 
in a row, will be issuing a special weather statement for roughly 
the w half of Upper MI to highlight elevated wildfire potential.
On a final note for today, sporadically thru the day, fcst soundings 
reveal a little bit of cape for parcels lifted from the mid cloud 
deck. So, while there may be some radar returns from the mid clouds 
at times today, the abundance of dry air blo the cloud deck will 
prevent any sprinkles from reaching the ground.  

Tonight, waa/isentropic ascent continues as a weak shortwave trof 
moves to the Upper Great Lakes. An 850mb trof also moves to Upper 
MI. Expect considerable mid/high clouds from the waa/isentropic 
ascent, and fcst soundings certainly show that. The soundings also 
reveal a little more instability aloft tonight. NAM suggests maybe 
100j/kg or so of CAPE for parcels lifted from somewhere in the 5-
7kft layer. If this instability does in fact materialize, the weak 
shortwave/850mb trof/isentropic ascent could yield some isold -shra 
tonight. Given little model consensus for shra tonight, varying 
locations of shra for those that do show some pcpn, and lingering 
dry air at the low-levels, opted to hold onto a dry fcst tonight. 
Expect low temps generally in the upper 30s and lower 40s.

.LONG TERM...(Monday through Saturday)
Issued at 525 AM EDT SUN APR 4 2021

A shortwave should move east out of our area Monday. Behind it, a 
cold front is expected to push through the area Monday night into 
Tuesday. Rain rates could be moderate at times as the cold front 
passes. Also, there is a slight chance for thunderstorms over the 
west late Monday afternoon and into early Monday evening. 
Afterwards, a low in the Central Plains should bring some light 
rainfall across the area during the midweek. This rainfall may 
continue until next weekend. 

A shortwave over the U.P. Monday morning is expected to prog 
eastward throughout the day, which should reduce cloud cover in the 
west. This reduction in cloud cover will allow for radiational 
heating from the Sun, which in turn will increase the instability of 
the air. No rain is expected with the shortwave, as NAM model 
soundings show a significant dry layer in the lower levels. Only in 
southern Menominee county does it look like the dry layer might be 
weak enough to allow some light rainfall Monday morning. 

Behind the shortwave, a cold front is expected to move through the 
area from Monday evening to Tuesday. Because of the instability 
caused by radiational heating in the west, we could see a few 
thunderstorms pop-up in that vicinity late Monday and early Monday 
night; MUCAPEs look to reach close to 1000J/kg at places and 
frontogenesis should provide enough lift to get parcels high enough 
to where ice formation can occur. The NAM3km and NAM show a line of 
showers/storms moving across the area Monday night and Tuesday. 
Therefore, I believe that we should expect a line of showers/storms 
to move across the CWA Monday night and Tuesday, with any storms 
cutting out by the later parts of the night. This front should also 
provide us with a soaking rain across the U.P., with some spots 
along the front seeing moderate rain rates (this is backed up by 
PWaTs being in at least the 90th percentile in the ensembles Monday 
night and Tuesday). 

Behind this front, we should expect a little bit of clearing Tuesday 
afternoon in the west before some light rainfall returns Wednesday 
as a low develops over the Central Plains. Models seem to indicate 
that the low should lift across northern IL and move N/NE later in 
the week as it weakens. The Euro and GFS models show the low 
spinning around our CWA and weakening until the end of the extended 
period. Therefore, we may receive rainfall for multiple days on end 
as this closed low approaches, and slowly leaves, our area as it 
weakens. The chances of rain should diminish throughout the late 
week into next weekend, as we should receive less and less moisture 
from the Gulf of Mexico as time goes by.
&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 112 AM EDT SUN APR 4 2021

VFR conditions are expected through the forecast period with only 
periods of mid and high clouds. South to southeast winds will 
increase today and become gusty at times to near 20 knots in the 
afternoon.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 505 AM EDT SUN APR 4 2021

As high pres over the Upper Great Lakes shifts e and ne today and a 
low pres trof approaches the Upper Mississippi Valley, expect 
increasing easterly winds. By late aftn, gusts up to 20-25kt will be 
possible over portions of western and central Lake Superior. While 
the winds may subside a bit over the w late tonight, winds will 
increase further over central and eastern Lake Superior with gusts 
up to 30kt possible. Little overall change in winds is expected on 
Mon, though some gale force gusts to 35kt will become possible 
toward the U.S./Canada border late. A weakening trof will move 
across Lake Superior Mon night and Tue. As this trof arrives over 
western Lake Superior, winds will diminish to blo 20kt Mon night, 
then remain under 20kt Tue. SE winds of 20-30kt will continue over 
the e half of Lake Superior Mon night with a few gale force gusts 
possible. Winds will then diminish to blo 20kt Tue. E to NE winds 
will be on the increase Wed/Thu as low pres organizing over the 
central Plains on Wed lifts toward the Upper Mississippi Valley on 
Thu. Probably looking at winds increasing back into the 20-30kt 
range over much of Lake Superior, beginning first over western Lake 
Superior.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...Rolfson
LONG TERM...TAP
AVIATION...JLB
MARINE...Rolfson