887 
FXUS63 KMQT 110901
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
501 AM EDT Fri Oct 11 2019

.SHORT TERM...(Today and tonight)
Issued at 415 AM EDT FRI OCT 11 2019

Early this morning, low pressure continued to develop over 
northern Minnesota. Out ahead of the surface low, warm air 
advection continued to stream northward, with a gradually increase
in deeper moisture and some scattered showers. Gusty winds also 
persisted, with gusts ranging between 15 and 25 knots across the 
area. With pre- dawn temperatures in the mid/upper 50s and 60s 
already this morning, expect a warm start to the day with highs 
today in the mid to upper 60s. Out west, high temperatures will 
occur early in the day, with falling temperatures this 
afternoon/evening, as colder air starts to work into the region. 

Today we will also see breezy conditions develop, especially 
across parts of central and much of eastern Upper Michigan. With 
the low deepening throughout the day, and a 50 knot LLJ lifting 
across the east half, this certainly will support wind gusts of 25
to 30 knots this afternoon. Elsewhere, across the west half, 
breezy conditions are expected, but will switch around and become 
southwesterly as an occluded front lifts north later today. Breezy
winds will also bring high waves and the potential for minor 
beach erosion today, over the Tip of the Keweenaw Peninsula and 
then along the Lake Michigan shoreline. 

As for precipitation today, rain showers are expected to increase
in coverage as the main axis of 1-1.5'' PWATs axis shifts east 
across the area and coincides with strong large-scale lift. Model 
fields do not show too much in the way of instability, but there 
are hints that skinny CAPE may develop, this coupled with ample 
upper-level divergence, it certainly isn't out of the question 
that we could hear a rumble or two of thunder. While much of the 
Upper Peninsula will see rain showers today, the main concern for 
heavier rain looks to be along and north of Lake Michigan. This is
where there will be the longest stretch of training 
precipitation, deeper moisture and lift throughout the day today. 
On top of that, with Lake Michigan still sitting around 60 
degrees, that should help serve as a local moisture source as 
well. It is not out of the question that there could be a few 
hydro issues that develop, but expect those mostly to be confined 
to areas with poor drainage. As the occluded front lifts northeast
into the west this afternoon, the deeper moisture and lift will 
starts to weaken as the system's dry slot starts to move in. While
this dry slot does look to put an end to precipitation out west 
this afternoon, it is possible there could be a few scattered 
showers late in the day after the main widespread showers have 
moved out. 

Tonight, cold air continues to wrap north and east across the 
Upper Peninsula as the dry slot continues to move in. This will 
gradually favor heavier precipitation shifting east of the area 
into Canada and a drying trend overnight. The one area that looks 
to be an exception is northeast of Lake Michigan, where southwest 
flow and colder air moving up the lake will favor destabilization 
and increased chance for lake effect rain showers. Given the lake 
influences with temperatures expected to remain above freezing 
tonight, precipitation is expected to remain all rain. This colder
air will also favor a cold night across the region, with the 
potential for sub-freezing temperatures across the west and 
central. With this cold air advection coming from the southwest, 
not a traditional track, there will be little in the way of 
downwind lake influences/moderation to help keep temperatures 
warmer inland. The only thing that could locally keep temperature 
a bit warmer would be lingering cloud cover and periodically gusty
winds.

.LONG TERM...(Saturday through Thursday)
Issued at 459 AM EDT FRI OCT 11 2019

Cool, unsettled weather will dominate the long term portion of the 
fcst (high temps each day will mostly be in the 40s). Developing mid-
level low currently over SD/Nebraska will deepen today and tonight 
as it moves to far nw MN, reaching an impressive negative height 
anomaly of 370m at 500mb. Ridging, positive height anomaly moving 
across western Canada will then link up with a strong positive 
height anomaly over eastern Canada, resulting in the MN mid-level 
low only drifting very slowly eastward over the next few days, 
passing over or in the vcnty of far northern Lake Superior Sun 
night. The system will then get a kick to the ne Mon/Tue as a 
shortwave trof dropping se across BC on Sun reaches the Dakotas Mon 
night. Under the influence of the mid-level low, cool and at times 
showery weather will prevail Sat thru Mon. Shower coverage will be 
modulated by several shortwaves pivoting around the mid-level low. 
It won't be until later Sun/Mon that s to sw low-level flow veers w 
to nw. So, lake enhancement off Lake Superior won't be an issue 
until then. Before the winds veer, flow will probably have enough of 
a southerly component for lake effect rain off Lake MI to affect the 
eastern fcst area. Boundary layer temps thru Mon will be cool enough 
to support some snow at times, mainly over the high terrain of the w 
half of Upper MI. Nothing of note is anticipated thru Sun. Once the 
winds veer w to nw, air mass will have moderated slightly, so still 
not expecting any snow of note. Shortwave trof reaching the Dakotas 
Mon night will go on to spin up a sfc low somewhere over the Great 
Lakes region on Tue. Depending on where the low develops, widespread 
pcpn may develop across the fcst area, probably just rain, but some 
snow could occur. Following this shortwave, cool nw flow and some 
light lake effect pcpn will linger Wed. Late next week, medium 
guidance suggests rising heights and some warming. 

Beginning Sat, the day will probably start out on the dry side for 
most of the area under mid-level dry slot. With 850mb temps around 
-6/-7C over northern Lake MI where sfc water temps around 15C, there 
should be some lake effect shra streaming off the lake under sw 
flow. Winds will have enough of a southerly component for the shra 
to clip the eastern fcst area. Out w, return of deeper moisture may 
support some -shra/-shsn by late morning. During the aftn, a 
shortwave will pivot into the area, resulting in development of sct 
pcpn. Downwind of Lake MI, the shortwave will lead to a dramatic 
increase in pcpn as synoptic forcing overspreads the strong 
overwater instability. With CAMs generating MUCAPE of a few hundred 
j/kg over the lake, not totally out of the question that there could 
be a rumble of thunder. Will be a chilly day with highs in the upper 
30s to mid 40s. 

A second shortwave will quickly follow the first Sat night, 
resulting in sct to nmrs showers across the area. The more 
signficant pcpn will be downwind of Lake MI, clipping the far 
eastern fcst area. Wetbulb zero heights suggest pcpn will be mostly 
snow Sat night, except downwind of Lake MI. Any snow accumulation 
will be minor, under 1 inch. 

During Sun/Sun night, sfc low pres trof will finally move across 
Lake Superior, veering winds to the w to nw and bringing lake 
enhancement off Lake Superior into Upper MI. However, as this 
occurs, wetbulb zero heights rise to mostly above 1500ft in the 
areas that would be affected by w to nw wind lake enhancement, 
suggesting ptype will become rain except well in the interior high 
terrain south of Houghton Sun night. Any snow accumulations will be 
under 1 inch. Elsewhere, sct mixed -shra/-shsn will turn to just 
-shra Sun aftn. Pcpn will then end across the s central Sun night. 

Lingering light w to nw flow lake effect pcpn will then wind down on 
Mon as mid-level low shifts ne and heights rise (120m at 500mb).

On Tue, attention shifts to the next shortwave trof that will spin 
up a sfc low over the Great Lakes region. GFS has been and continues 
to be quickest in developing the sfc low. It also remain farther n, 
suggesting a widespread rainfall. GFS/CMC ensembles show a fair 
amount of spread, but do support a fcst of at least chc pops as does 
the ECMWF. Cyclonic n to nw low-level winds after the system passes 
will support another round of lake enhanced pcpn transitioning to 
lake effect pcpn Tue night/Wed that will include some snow over the 
high terrain.
&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 122 AM EDT FRI OCT 11 2019

Expect scattered showers to spread through western Upper Michigan 
overnight bringing gradually lowering cigs. Conditions should drop 
to IFR at KSAW Fri morning as heavier and more persistent rain moves 
in along with continued moisture advection. A greater low level wind 
downslope component KIWD and KCMX may keep cigs mainly in the MVFR 
range. As a cold front moves through later Fri afternoon, conditions 
will improve to MVFR as winds veer to the southwest.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 415 AM EDT FRI OCT 11 2019

Low pressure west of the lake this morning will deepen throughout 
the day as it lifts into northern Minnesota. This will favor 
southeast gales of 35-40 knots over the north central and eastern 
parts of the lake this morning through the afternoon/evening hours. 
The low pressure system will occlude and start to weaken later 
today/tonight, sending a surge of strong cold air advection and 
southwest winds moving in from west to east across the lake. 
Increasingly unstable conditions over the lake will favor gales of 
35-40 knots later today and overnight, once winds switch around and 
become southwesterly. Confidence is highest in this second round of 
gales developing over the west half of the lake where overall shear 
aloft is stronger; therefore, have issued a Gale Warning for western 
parts of the lake this morning. 

Low pressure will remain parked over northern Minnesota throughout 
the weekend, but it will gradually weaken as the system becomes 
vertically stacked. That being said, lingering gales early Saturday 
morning will subside and leave behind south-southwest winds of 20 to 
30 knots. Low pressure starts to push eastward on Sunday over 
northern parts of the lake, this will allow winds to subsidence to 
15 to 25 knots, and become westerly throughout the day. Elevated 
west-northwest winds of 15 to 25 knots persist through Monday. Then, 
albeit only for a short period of time, winds look to relax below 20 
knots on Tuesday before ramping back up to around 20 to 25 knots 
through mid week.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 11 PM EDT this evening for LSZ251-266-267.

  Gale Warning from 5 PM EDT /4 PM CDT/ this afternoon to 8 AM EDT 
     /7 AM CDT/ Saturday for LSZ162-263.

  Gale Warning until 5 PM EDT this afternoon for LSZ244-245-264-
     265.

Lake Michigan...
None.
&&

$$

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