009 
FXUS63 KMQT 041926
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
326 PM 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 night through Sunday)
Issued at 321 PM EDT SUN APR 4 2021

Models now appear to be trending toward a more active weather 
pattern through much of the extended with opportunities for much 
needed rainfall across the area.  

Beginning Mon night into early Tue, a shortwave moving from northern 
Manitoba towards Hudson Bay will propel a cold front into Upper Mi 
late Mon night into Tue morning. Model soundings show some increase 
in elevated instability into the western and perhaps south central 
fcst area to around 1000 j/kg which could support some thunderstorm 
activity in these areas into the evening hours ahead of the 
approaching frontal boundary and at nose of 30 kt LLJ. Most models 
(with the exception of the NAM) have instability waning and thus the 
threat of t-storms diminishing overnight Mon night into early Tue 
for the rest of cwa ahead of the advancing frontal boundary. While 
soundings show nice veering profiles and curved hodographs into this 
area, effective shear is somewhat weak, generally 25-30 knots, so 
not really expecting any stronger storms to support large hail into 
the west. PWATs rising to around 1.00 inch and modest 850 mb 
transport should support some rainfall across the rest of the cwa 
late Mon night into early Tue with the passage of the cold front, 
but the question is how much? Best dynamics/forcing along the front 
is well north of Lake Superior into far northern Ontario. GFS 
ensembles and SREF plumes indicate qpf of maybe .25 to .5 inch west 
tapering to .1 to .25 of an inch central and east.   

Behind this front, expect some clearing Tuesday afternoon west and 
central before some light rainfall returns Wednesday to mainly the 
west half as a low begins to emerge from the Central Plains. Models 
indicate that the low should lift ne into the Upper MS Valley and 
Upper Great Lakes region by the end of the work week as it weakens. 
The GFS and the ECMWF models then show the low continuing to persist 
over the Upper Great Lakes through next weekend. Gulf moisture being 
drawn northward ahead of the low with PWAT values rising to 1.00-
1.25 inches by late Wed into Thu will result in increasing chances 
of much needed soaking rainfall across the area. Rain showers will 
gradually diminish in coverage by late week (Fri into the weekend) 
as the low continues to weaken over the area and the best tap of 
Gulf of Mexico moisture gets shunted east.
&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 130 PM EDT SUN APR 4 2021

Mid level cloud cover with dry air at the lower levels will maintain 
VFR conditions at KIWD/KCMX/KSAW through this TAF period. South to 
southeasterly winds are expected at KIWD and KSAW with some gusty 
winds near 20kts through this 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...Voss
AVIATION...JP
MARINE...Rolfson