Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/08/21

Area Forecast Discussion

National Weather Service Gaylord MI

 919 PM EST Sun Mar 7 2021

.UPDATE...
Issued at 919 PM EST Sun Mar 7 2021

00Z APX sounding showed a very narrow mid-level moist layer,
centered on 750mb, and very dry air below (850mb dew pt depression
was some 40C). But the initial shortwave moving thru the area has
increased that moist layer and steepened lapse rates. Convective
mid-level returns continue to cross northern MI, and 20dbZ have
been seen less then 1500ft AGL ne of the radar. Though no precip
has been reported by any ob site, do suspect that some flakes are
reaching the ground in isolated spots. Have added a small chance
of flurries/light snow showers to parts of northern MI this
evening.

Guidance continues to aggressively moisten the mid-, and to some
degree low-, levels overnight in eastern upper MI. Substantial
theta-e advection is driving this deeper moistening, which
also develops an above-freezing warm layer aloft. Actually getting
precip out of this is quite uncertain; the RAP has occasionally
been relatively aggressive is bringing a narrow band of showers
across much of northern MI overnight. But at the present, the RAP
and most other near-term guidance is dry, and only a few weak/
meager returns are noted upstream (moving into ne WI). Will
continue to ride with a small chance for -FZRA overnight in the
Straits area and points north. QPF would be very small, and any
potential impact should be likewise.

&&

.NEAR TERM...(Through Tonight)
Issued at 342 PM EST Sun Mar 7 2021

...Spotty Light Wintry Precip Overnight...

High Impact Weather Potential: Minimal.

Pattern Synopsis/Forecast: Sharp short-wave ridge axis is just
upstream...stretching from the western U.P. down through Illinois.
Short-wave impulse and associated surface trough/boundary follows
close behind, swinging through south-central Canada into the
Upper Midwest with a batch of high level warm advection forced
cloud cover pressing into the western lakes. Also of note, a
narrow line of mid cloud cover is crossing central Upper Michigan
down toward GRB with some spotty radar returns. Line of elevated
weak convection appears tied to advancing mid level theta-e axis
coincident with some steeper lapse rates.

Meanwhile, large area of surface high pressure remains in control
of our weather, stretching from the central lakes southward to
the Gulf with southerly return flow increasing and leaning through
the Upper Midwest into the western lakes.

Dampening short-wave impulse is expected to slide into and
through the northern lakes region through tonight while surface
cold front advances into the far western Great Lakes by early
Monday morning. Axis of low level warm air (>0C at 850 MB) ahead
of the boundary will fold into the region later tonight resulting
in a narrow ribbon of low-mid level warm advection forcing
sliding through.

Primary Forecast Concerns: Precip chances and type through
tonight along with stratus/freezing drizzle possibilities.

Details:

First off, initial narrow line of mid cloud cover and elevated
radar returns will move through the CWA through this evening
(recent NAMNEST/HRRR runs clearly pick up on the elevated
convection). But given the amount of dry low level air in place
right now (single digit dewpoints), I am doubtful that much gets
to the ground. Just mentioning it just in case.

Meanwhile, NAM/GFS guidance remain very bullish in developing low
cloud cover through the Upper Midwest late this afternoon and
further expanding into the northern lakes region tonight.
However, again given the amount of low level dry air entrenched
through the region and no sign of any low cloud development in
the Upper Midwest at this juncture, I am skeptical that we see
much low cloud/drizzle development...at least through tonight
anyway (we could see some post-frontal low cloud/drizzle
development on Monday).

But, spotty light warm advection forced precip is possible late
this evening and through the overnight hours. Warm nose aloft in
concert with slightly steeper lapse rates aloft (pushing 7C/Kg in
the 700-500 MB layer) and below freezing surface temps might bring
some spotty freezing rain drops/sleet pellets across eastern
Upper Michigan and the tip of the mitt. Minimal QPF, so I
anticipate very minimal if any impacts.

&&

.SHORT TERM...(Monday through Wednesday)
Issued at 342 PM EST Sun Mar 7 2021

High Impact Weather Potential: Minimal, except for perhaps some
lingering wintry precip across Eastern Upper...

Pattern Synopsis/Forecast:

Shortwave passing through the flow to our north with attendant
surface reflection looks to be exiting stage right Monday
morning...though perhaps not without lingering a bit of cloud cover
across the area, with light wintry precip exiting the Eastern UP
through the morning hours. As mid-level subsidence presses into the
region ahead of broad upper-level ridging...will look for surface
high pressure to return during the afternoon in conjunction with
temperatures warming to above normals...at least, across much of
northern Lower. A stronger push of warm air looks to enter the
region going into the day Tuesday...as return flow strengthens ahead
of next system upstream in the central Plains. Warm, moist air
advecting into the area through the day Tuesday should lead to
snowmelt...and perhaps fog potential as well later in the day. Warm
air advection Wednesday ahead of the next system should lead to
another warm day...though it will be rainy and breezy as this system
moves into the region.

Primary Forecast Concerns: light wintry precip linger Monday
morning...temperatures Tuesday and Wednesday...precip chances
and gusty winds late Tuesday into Wednesday...

First thing to deal with will be the potential for that light wintry
precip to linger over the area Monday morning for a time. Moisture
depth appears to get even shallower with time going through the day
Monday...though model derived soundings indicate there may be some
potential for low clouds to linger around through part of the day
Monday as we`re marginally sideswiped to the north by a weak,
latitudinally-oriented cold boundary late Monday into Monday night.
Not entirely sure how well that idea will pan out...given that some
models are currently having a hard time with upstream low clouds
(i.e., too cloudy vs reality)...so continued with an idea of
clearing at least in the afternoon, though clouds should stick
around through at least the early part of the day. Either
way...temperatures across Eastern Upper should approach and/or
exceed the freezing mark by mid-late morning/early afternoon, which
should serve to mitigate the frozen precipitation potential. Even
so...Monday morning commuters across northern portions of the
area...especially north of the Bridge...may want to leave a little
extra time in case of slick spots (or having to run the defrosters).

Temperatures Tuesday into Wednesday may not be entirely as
straightforward as they seem...though the idea of much warmer air
seems quite plausible given warm advection not only at the
surface...with surface high pressure across the southeastern US and
low pressure in the Plains...but also through a majority of the
column...as flow through the vertical turns primarily southwesterly
ahead of troughing aloft. Looks as though perhaps consensus guidance
is not as bullish with warmth today as in previous days...though
still warm, with highs potentially into the 50s. Warm, moist
advection, as mentioned above, may serve to melt at least a portion
of the snowpack, with potential for dewpoints to rise above freezing
by mid-week. This may throw a bit of fog potential into the
forecast, though confidence is not extremely high in this attm.
Currently looks like best chance for that would be later Tuesday
into Wednesday with the warmest and moistest air closest to
saturation. Will have to keep an eye on this going forward. Even
so...will still look for temperatures to be warm and springlike,
even if the weather outside looks grungy.

There is some uncertainty in exactly how the pattern for Tuesday and
Wednesday unfolds...though there seems to be pretty good agreement
in two systems moving through the central Plains...the first one, a
bit further west, which attm keeps the majority of its precipitation
along or north of the Canadian border. Can`t rule out that we won`t
see anything with it, though...especially later in the day
Tuesday...as its cold front approaches. As upper level troughing
moves eastward...and another shortwave moves through the
flow...looks like that second low pressure to develop in the central
Plains will ride up the cold front/baroclinic zone left by the first
low...allowing the second system to set its sights a little more
firmly on Michigan. Since this second system will be a little
further east than the first...we should be in a better position for
warm/moist advection...and do note that moisture transport is
stronger and more anomalous across the Great Lakes area...with pwats
near or above climatological maxes for March 10-12th. Not a
surprise...given the wide open Gulf...strong southwesterly
flow...and potential for some upper level ascent working in our
favor with upper level speed max to our north placing us in a
position favored for divergence aloft and upward motion. Bottom
line:  Wednesday looks like a pretty wet day overall. It should be
relatively breezy/gusty as well, as pressure gradient increases
between high pressure to our southeast...and low pressure
encroaching from the west.

.LONG TERM...(Wednesday night through Sunday)
Issued at 342 PM EST Sun Mar 7 2021

High Impact Weather Potential: Minimal for now...

Looks like precipitation will likely continue into Thursday as
well...as it looks like the cold front with this system will be
moving through during the day. There are some differences between
the models for Thursday and beyond...which will determine how much
cold air will get into the region behind the system as strong,
latitudinally-oriented jet sets up somewhere in the vicinity of the
Great Lakes....with troughing across the southwestern US. This lends
itself to a fair amount of uncertainty in the forecast beyond Friday
(actually, beyond Thursday, for what it`s worth), so will hold off
on playing around too much with the long term until models can
settle their differences. One thing does look reasonable despite the
uncertainty, though:  it should be cooler in the latter half of the
week than in the first half of the week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 646 PM EST Sun Mar 7 2021

Some MVFR cigs possible late Monday. LLWS tonight.

VFR conditions out there now, with cirrus overhead and a few
patches mid clouds edging in. High pressure is moving off to the
east, and southerly flow will increase tonight ahead of cold front
now in MN. Expect mid/high clouds to thicken further, but expect
VFR conditions thru most of Monday. Some potential for MVFR cigs
to develop late Monday, but for now only the APN TAF has this
outright.

Southerly winds increase tonight, with LLWS overnight. Sw to w
breezes on Monday.


&&

.MARINE...
Issued at 342 PM EST Sun Mar 7 2021

South to southwest gustiness increases tonight ahead of a cold
front that folds into the region late tonight into Monday. Gusts
sufficient for small craft advisory headlines for most of the Lake
Michigan and Huron nearshore waters into Monday morning.
Winds/waves diminish through the day Monday and all headlines will
likely be allowed to expire as planned.

No additional marine headlines anticipated through Tuesday at this
juncture.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY until 7 AM EST Monday for LHZ346.
     SMALL CRAFT ADVISORY until 11 AM EST Monday for LHZ347>349.
LM...SMALL CRAFT ADVISORY until 7 AM EST Monday for LMZ323-342-
     344>346.
LS...NONE.
&&

$$

UPDATE...JZ
NEAR TERM...ADAM
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...JZ
MARINE...ADAM



Area Forecast Discussion

National Weather Service Denver/Boulder CO

 831 PM MST Sun Mar 7 2021

.UPDATE...
Issued at 824 PM MST Sun Mar 7 2021

No significant adjustments planned this evening. The upper level
ridge will shift further east overnight with an increasing
southwesterly flow aloft. Should see an increase in high level
cloudiness late tonight and Monday. Models show a weak embedded
weak system near the Four Corners region by 12z Monday, it then
moves across northeast CO in the afternoon. This already reflected
in the current grids, so no changes at this time.

&&

.SHORT TERM...(This evening through Monday)
Issued at 230 PM MST Sun Mar 7 2021

Subsident flow under an upper level ridge has been in place today
and will continue to be tonight. This has lead to well above
normal temperatures and dry conditions. Lows tonight will be 10 to
15 degrees above normal.

During the day tomorrow, a weak trough that is associated with the
high clouds currently streaming onto the southern California
coast will move across Colorado. This trough does not have much
cold air aloft or QG ascent associated with it so it is not
expected to bring precipitation to the area. It will bring high
level cloudiness to the majority of our CWA for much of the day
keeping high temperatures close to the same as today despite the
warmer 700 mb temperatures. The shortwave trough along with good
mixing from mild temperatures may help bring down some gusty
westerly winds but overall winds should be light. The HRRR would
suggest possible Red Flag conditions across southern Lincoln and
Elbert Counties tomorrow but the HRRR way over-mixes the boundary
layer. It doesn`t account for the considerable cloudiness expected
tomorrow which should keep relative humidities higher than the
model forecast and winds lighter. Therefore, no fire weather
highlights were issued.

.LONG TERM...(Monday night through Sunday)
Issued at 143 PM MST Sun Mar 7 2021

For Monday night and Tuesday, Colorado will be under a moderate
southwest flow aloft. The airmass will remain relatively dry so no
precipitation expected. With the stronger southwesterlies, cross
sections showing increasing cross barrier flow of 35-50kt from late
Monday evening through Tuesday morning. Could see some gusts up
to 60 mph over higher mountains. In the meantime, a shallow cold
front will push across the northeast plains Tuesday afternoon with
shallow easterly flow developing with some slight cooling behind
the frontal push. The exception may be along higher terrain of the
Palmer Divide where gusty southwest winds may continue leading to
higher elevated fire danger. Still threat looks marginal so will
not issue any fire weather watches.

On Wednesday, expect cooling in all areas behind the cold front
while an upper level disturbance and strong jet streak slices
through the state. Some mountain moisture, but don`t expect much
more than chance pops and minimal snow accumulations with
southwest to west flow for earlier in the day, then better chances
in the afternoon with cold advection and a shift to northwest
mountain top flow. 700mb temperatures cool to around -5C which
will result in temperatures back into the 50s.

The weather pattern becomes more complicated from Thursday and into
the weekend as long range models having a hard time with a consensus
on how to handle the next chunk of Pacific energy moving onshore
on Thursday. As has been the cast in previous few days, the GFS
continues to be the more progressive model with the upper low
shifting towards the 4 corners on Friday morning and then slowly
moving eastward across southern Colorado on Friday and into early
Saturday. The Canadian and European solutions are slower and
further south with the track, more across New Mexico over the
weekend. Potential for significant precip over our county warning
area depending on tracks, so certainly bears watching as we head
into the week. The system should be bringing enough cold air for
mainly snow chances by the weekend and potential for heavy snow
somewhere (especially east slopes) in Colorado. For now will
continue to show a cooling trend into the weekend with a least of
chance of rain and snow for the entire area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 824 PM MST Sun Mar 7 2021

VFR conditions through the TAF period. Southeasterly winds will
veer towards drainage by late evening. As a shortwave trough
passes across the area tomorrow, it will aid in developing
westerly winds by the afternoon. There may be a couple gusts up to
20 knots tomorrow afternoon from the west.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Cooper
SHORT TERM...Danielson
LONG TERM...Entrekin
AVIATION...Cooper/Danielson



Area Forecast Discussion

National Weather Service Detroit/Pontiac MI

 607 PM EST Sun Mar 7 2021


.AVIATION...

Surface ridge and very dry airmass in place will continue to support
clear skies (below 20 kft) and light winds into tonight. Strong warm
advection will ensue late tonight and bring in mid/upper clouds as
southwest winds develop. Southwest winds will then increase on
Monday morning with gusts up around 20 knots by early afternoon.
While cigs will lower, they should bottom out only in the 5-10kft
layer.

.DTW THRESHOLD PROBABILITIES...

* None.

&&

.PREV DISCUSSION...
Issued at 353 PM EST Sun Mar 7 2021

DISCUSSION...

Center of surface anticyclone has become positioned this afternoon
in a lake aggregate fashion over the northern Lake Huron basin.
Obvious signal showing up in surface observations with a lake breeze
dynamic and onshore flow for just about all of the Lakeshore. For
interior sections of Lower Michigan, nil surface flow has put the
brakes on deep mixing. Have tweaked the temperatures grids for the
remainder of the afternoon lower a degree or two.

Deep anticyclonic gyre aloft will push eastward through portions of
Indiana and the Ohio River Valley tonight with return southwesterly
flow becoming firmly established for Monday. Surface warm front/warm
sector is shown to push eastward across all of the area between 9-
12Z with a quasi-stationary front developing along the northern
flank of the warm sector across northern Lower Peninsula. NAM
solution is really hung up on this frontal boundary suggesting it
will even push southward late afternoon down into the Saginaw Bay
region. Suspect some questionable radiative forcing within the
models is leading to some overzealous frontal behavior. The HRRR
remains much warmer across the Tri Cities and does not support the
same frontal behavior through much of the afternoon. There is some
uncertainty with regards to cloud cover over the northern cwa which
may impact insolation. High confidence that cold air advection
washes southward by the early evening hours. Generally sided with
the non-nam solution for high temperatures, but do feel a non-
diurnal curve is likely across far northern cwa. Interesting surface
trough feature predicted at 18Z should help in mechanical mixing and
pushing mixing depths upwards of 6.5 to 7.0 kft agl layer. Basic
mixing technique suggests 0.5C at 800mb will be good for
temperatures well into the mid 60s. Settle on highs ranging from the
middle 50s north (early) to the middle 60s across Metro Detroit.

Frontal boundary will settle southward becoming stalling out in
vicinity of far southern Lower Michigan for Tuesday. Despite upper
riding the main warm sector will become more increasingly organized
with height falls across the Plains. Models very persistent on
easterly trajectory to surface winds which will lead to an onshore
component. Went more tempered with highs for Tuesday with cooler
readings near the Lakes/Rivers. Highs are expected to range in the
upper 50s to the lower 60s.

All out warm sector with deep southwesterly flow for Wednesday. Lead
shortwave energy is expected to stream across the area which is
expected to lead to extensive cloud cover. A secondary warm front is
expected to lift into the area during the afternoon leading to rain
shower chances. Main surface low is progged to deepen and lift
northward through the western Great Lakes Wednesday night. Latest
forecast data suggests main time window for precipitation across
Southeast Michigan will be during the day on Thursday. Trailing cold
front from low pressure passage is expected slow down over the state
in time for next upper level jet exit region and deep frontogenesis
response. Notable aspect of the Thursday forecast is data suggesting
surface dewpoints reaching the middle 50s.

MARINE...

Quiet weather heading into tonight as high pressure is centered over
the Great Lakes. The high will drift eastward through the evening
pulling the ridge axis through the area by tonight. This will cause
the calm winds to become southerly overnight. A trough axis
extending south out of a low that will across Hudson Bay, will sweep
across the northern Great Lakes tonight. The gradient will tighten
between this trough and current ridge causing winds to ramp up
tonight into Monday.  Gusts will be limited by warm air advection
over the waters so expecting gust up to 25 knots. High pressure
fills back in quickly behind the weak trough for Tuesday with
continued southerly flow.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&

$$

AVIATION.....DG
DISCUSSION...CB
MARINE.......DRK


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.



Area Forecast Discussion

National Weather Service Grand Rapids MI

 832 PM EST Sun Mar 7 2021

LATEST UPDATE...
Update

.SYNOPSIS...
Issued at 235 PM EST Sun Mar 7 2021

- Moderating temps, low RHs and Gusty winds next few days

- Several rounds of rain possible middle to end of the week period

&&

.UPDATE...
Issued at 832 PM EST Sun Mar 7 2021


I have increased the forecast high temperatures on Monday about 5
degrees across most of the CWA. This is based on the use of my
1000/925 thickness tool and that this also agrees nicely with the
HI RES HRRR temp forecast. The model sounding forecast from the
NAM shows a hard to imagine low level inversion near 2000 ft that
is not shown by either the HRRR or RAP models. Given that highs
should be more like the mid 50s central CWA and lower to mid 60s
near I-69.


&&

.DISCUSSION...(This evening through next Sunday)
Issued at 235 PM EST Sun Mar 7 2021

- Moderating temps, low RHs and Gusty winds next few days

Strong warm air advection develops later tonight and more so on
Monday as a low level jet moves in. Southwesterly gusts are likely
to reach 30 mph as the mixing height increases during the day. Up
north where there is still some snowpack...high temperatures are
likely to reach the low 50s while further south some near 60
degree readings look possible given the 925 mb temps shown to rise
into the 5 to 8 deg C range. It will mostly be dry air advection
on Monday so very low RH values look likely to occur. The NAM is
showing low clouds moving in Monday night into Tuesday...which
could impact the temperatures somewhat. Other models are not being
as aggressive as the NAM on this scenario.

Strong warm air advection resume Tuesday into Wednesday. The temp
at 925 mb climbs several degrees each day with most locations
expected to see High temps in the 60s by Wednesday. There is some
uncertainty how deep we will mix Tuesday night into Wednesday.
This low level jet will be stronger but due to increasing cloud
cover...the mixing depth is shown to be lower. As a result there
will likely be less wind on Wednesday as compared to Monday
assuming less mixing.

- Several rounds of rain possible middle to end of the week period

Gulf moisture steadily streams in Tuesday into Wednesday with
PWAT values forecasted to top an inch starting Wednesday. This is
when a low level jet will be lifting through the region. Showers
are looking increasingly likely through the day on Wednesday. A
slow moving frontal zone moves in from the west Wednesday into
Thursday and some models stalling it out for 24 hrs...not pushing
the front through til Friday. The upper level diffluence
increases Thursday as the trough pivots in from the west. That
will likely help to keep the rain going or generate another round
mainly for southern parts of the CWA. Some weakness in the
stability is shown as well...so there may be a thunder risk as
well.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 631 PM EST Sun Mar 7 2021

There is still no rain in our forecast. In fact the lowest
ceilings are around 10,000 ft associated with the warm front
coming through. Those lower ceilings will during the daytime on
Monday.

There will be low level wind shear tonight as winds above the
boundary layer will be from the southwest around 40 to 45 knots.
Surface winds will become gusty on Monday.


&&

.MARINE...
Issued at 235 PM EST Sun Mar 7 2021

As one low level jet moves in tonight into Monday...the winds will
be on the increase over the nearshore waters. South to
southwesterly gusts are likely to top 25 knots and build the waves
up to at least 4 feet. This will support the current small craft
advisory that we have out.

Next later Tuesday night into Wednesday another low level jet
surges in. Gusts are likely to top 30 knots and we may make a run
at Gale conditions. One concern is how deep the mixing will be
given the seasonably stable conditions over the lake. No watch at
this time but it will be a consideration going forward.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 1 PM EST Monday for LMZ844>849.

&&

$$

UPDATE...WDM
SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS



Area Forecast Discussion

National Weather Service Marquette MI

 527 PM EST Sun Mar 7 2021

.SHORT TERM...(This evening through Monday)
Issued at 309 PM EST SUN MAR 7 2021

Current RAP analysis and GOES WV imagery now shows an upper level
ridge moving over Upper Michigan this afternoon after having an
upper level low just off to the northeast that brought cooler air,
especially over the north with lake-effect clouds. With the ridge
moving in, flow will become southerly bringing in waa across most of
the area except the east due to cooler air coming off of Lake
Michigan. Clouds will continue to increase through the afternoon as
a quick, but weak shortwave will move across Upper Michigan tonight
and will exit by early Monday morning. Did throw in some sprinkles
ahead with some cams showing very light rain as earlier guidance was
not picking up on that. There could be just enough fgen to have some
pcpn reach the ground but anything widespread is unlikely. Best
areas to see any pcpn will be across the north and east but may
reach as far south as Escanaba. Latest soundings indicate that pcpn
will fall likely as either dz/fzdz but think any icing will be
dependent on what temperatures will be doing at time of pcpn, which
at this time looks like they will stay at or above freezing. We`ll
see how later guidance handles this. If any icing were to occur, it
would be limited to a thin glaze on untreated surfaces. Will mention
this in HWO. Behind shortwave, clouds slowly clear from west to east
on Monday with partly to mostly sunny skies.

South to southeast winds will increase through the afternoon with
tightening pressure gradient, especially over the west and north
central between 15-25 mph. Could see some higher gusts along the
Lake Superior shoreline with downsloping winds They will begin to
relax once the shortwave passes and turn more out of the west for
Monday.

Temperature will be on the warm side with that waa moving in along
with the ridge and we did have good mixing from this morning,
allowing pretty big diurnal swings from lows around zero this
morning to the upper 30s and 40s. Slightly cooler air will remain
over the east from Lake Michigan. Lows tonight will not be not as
cold as this morning with expected temps from the mid 20s to low
30s. Highs Monday will be way above average for this time of year
with widespread 40s and low to possibly mid 50s near the WI border.

.LONG TERM...(Monday night through Sunday)
Issued at 314 PM EST SUN MAR 7 2021

By Monday night we will already be in the expected warmup period.
Synoptically, mid-level near zonal flow with a surface ridge
extending from the middle-Mississippi Valley up into Ontario will
start us off. As we move through the night, a shortwave will dig
southeast into Quebec, helping to ampliy the upstream mid-level
ridge. As this ridge builds east, surface high will also shift east,
allowing winds to become southerly and begin a good WAA regime. This
will help gradually fill in the skies as well as help temps climb
well into the 50s in the west and 40s east during the day. With
moisture also increasing, dewpoints above freezing are expected to
really help dig into the snowpack across the region.

Overnight Tuesday, a low developing over the Central Plains will
take shape and by morning, start tracking toward the Upper Great
Lakes. Ahead of the system, continued moisture advection in addition
to Tuesday`s ripening of the snowpack should result in fog
developing over the region. This will help to keep temps mild. There
is still a bit of uncertainity in the progression of the approaching
system. Generally speaking though, moderate rain is expected to
overspread the area in the afternoon with a switch over to freezing
rain or snow during the evening as the low and its cold front lift
northeast through Lake Superior into Ontario. The ptype switch
appears consistent among the 12z guidance but vary some given the
location differences. The GFS appears to be the fastest and bullish
with freezing rain, with rain spreading over the area during the
morning hours and with the low over central WI by 0z Thursday. The
Canadian, Euro and Nam all have similar tracks, but the Nam is
notablly slower. A look at the GEFS ptype spread really shows where
the subtle differences in the low`s track through the region impact
the placement and even existence of the freezing rain portion of the
phase-change train. I am a little more confident in the eventual
switch to snow in the far west and Keweenaw, where its looking like
a couple wet inches of snow will be possible overnight
Thursday.

Behind this system, it looks like we`ll return to more seasonable
temps. Daytime highs on Fri and Sat look to be in the 30s with some
near 40F possible in parts of Menominee County. Some lake effect may
be possible on Friday.
&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 526 PM EST SUN MAR 7 2021

VFR conditions will continue through most of the night at all
terminals. Cigs may drop to MVFR at all terminals later tonight with
either drizzle or freezing drizzle possible but confidence on cigs
is low at this time. Winds will decrease a bit and become more
westerly by Monday morning.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 309 PM EST SUN MAR 7 2021

Southerly winds will continue across the lake through the evening
around 20-30 knots with a few gale force gusts to 35 knots possible,
mainly on higher platforms. Winds will turn more westerly behind a
shortwave and will stay under 20 knots for Monday and into early
Tuesday. Southerly winds come back late Tuesday with 20-30 knots
across the east half of the lake through Wednesday morning. Winds
will fall at or below 20 knots for Thursday into Friday.
&&

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

$$

SHORT TERM...JH
LONG TERM...JP
AVIATION...07
MARINE...JH