December 2017 Observations and Discussions

[jaster220]

Extended looks fairly dry and downright frigid....no big storms. Hopefully, that changes. EC could be looking at one or two good storms.

Big or not from this range, you have to say it's at least looking active vs this snooze-fest zonal flow pattern. Cool stuff happens when we put a trough over da Lakes! Besides anything we might net with the Clipper next Friday, I'm seeing at least 3 more potential snows for SMI that aren't confined to the prime LES belts. Any/all of which could trend better as we get closer..

 

 

 

 

[Niko]

Temps could crack 50 or better on Monday. Looking forward to a nice, mild day right b4 the chill arrives.

[Niko]

Big or not from this range, you have to say it's at least looking active vs this snooze-fest zonal flow pattern. Cool stuff happens when we put a trough over da Lakes! Besides anything we might net with the Clipper next Friday, I'm seeing at least 3 more potential snows for SMI that aren't confined to the prime LES belts. Any/all of which could trend better as we get closer..

 

gfs_mslp_pcpn_frzn_us_33.png

gfs_mslp_pcpn_frzn_us_44 (1).png

gfs_mslp_pcpn_frzn_us_51.png

The last map looks more energetic than the first 2. Hopefully, some decent accumulations.

[Niko]

@Jaster,

 

On the 3rd map, check out that Low Pressure area sitting in the 4 corner states. That might be eyeing our area.

[GDR]

Monster AFD outta LOT..

 

”

.LONG TERM...

307 PM CST

 

Sunday night through Saturday...

 

As has been well advertised, the upcoming week will be a tale of

two seasons, as we abruptly transition from mid fall/early spring

weather to full blown winter. In our fall/spring regime through

Monday evening, these concerns/areas of focus are the mild temps,

strong to very strong winds Monday and showers and even thunder

potential Sunday night through Monday evening. Once we flip to

winter on Tuesday, concerns shift to cold temperatures, strong

winds Tuesday and breezy at times the rest of the period, low

wind chills and some snow potential.

 

For Sunday night through Monday night, models have remained in

decent agreement with a deepening surface low tracking from the

central/northern Plains to near or over Lake Superior by early

Tuesday. There has been a noted trend on much of the operational

and ensemble guidance the previous few model cycles toward a very

deep cyclone near or just north of Lake Superior by Tuesday

morning. This low path will keep us firmly entrenched in the warm

sector. Very strong warm advection aided by a ~50 kt southwest

LLJ and strengthening gusty southerly surface flow will result in

steady or slowly rising temps Sunday night and a very mild

starting point on Monday. Details are still a bit murky to be

sorted out with shower potential/coverage in the warm sector, so

mostly chance PoPs continue to be favored through Monday

afternoon. As mid-level lapse rates steepen, elevated instability

will increase, but mostly north of the area during the earlier

part of the day and then limited MUCAPE moving in from the west

during the afternoon.

 

Despite some at least spotty showers around and clouds on Monday,

the warm starting point, dewpoints approaching or exceeding 50,

and the strong WAA and southerly surface flow, highs into the 60s

are a good bet. Therefore have continued with temperatures in the

grids into the low 60s area wide, with mid 60s included in spots

south and also possible farther north per some of the warmest

guidance. Regarding winds, southerly gusts of at least up to 30

to 40 mph are probable due to the very tight pressure gradient and

stout pressure falls. Bufkit soundings indicate that Monday

afternoon through Monday evening ahead of the cold front, gusts

even higher than 40 mph are possible if mixing is deep enough.

 

Have highest confidence in shower coverage Monday evening with the

system`s powerful cold front and have also continued with chance

thunder with aforementioned steep mid-level lapse rates and

presence of modest MUCAPE across most of the area. As previous

discussion mentioned, the forced line of showers and embedded

thunderstorms Monday evening may also be able to mix down

isolated near severe gusts. Winds will quickly flip from southerly

to strong westerly behind the cold front, which will quickly end

precipitation from northwest to southeast. Temperatures quickly

falling into the 30s by daybreak Tuesday will accompany the

westerly winds gusting at least up to 30 to 40 mph, with again the

potential for advisory criteria gusts aided by impressive

pressure rises and strong CAA.

 

Strong CAA and gusty winds will continue through Tuesday as the

low-mid 970s mb surface low slowly pulls north in Ontario.

Temperatures are unlikely to rise much if at all from morning

lows. The combination of temperatures primarily in the lower to

mid 30s and westerly winds gusting up to 30-35+ mph will yield

late day wind chills in the upper teens to mid 20s, quite the

change from 24 hours prior. Some of the models indicate a weak

moisture starved wave speeding across the area Tuesday afternoon

associated with a secondary cold front. Have included chance

flurry mention north of I-80 for this and can`t rule out a brief

period of more robust snow than just flurries if this wave

materializes.

 

Operational and ensemble guidance continues to be in good

agreement on the large scale pattern through day 7 and beyond.

This will feature a highly anomalous and poleward extending

Pacific blocking ridge (positive Pacific North American

Pattern/+PNA and negative East Pacific Oscillation/-EPO)

connecting to Arctic region blocking (negative Arctic

Oscillation/-AO). Downstream of the anomalous blocking will be an

anomalously deep longwave trough with an axis roughly across

Hudson Bay and featuring gyres of the tropospheric PV working into

the northern US. While there is inherent uncertainty in the

specific day to day details this far out, confidence is high due

to the teleconnection pattern described above (similar to what

produced very cold to extreme cold in 2013-14 and 2014-15 winters)

in cold to very cold temperatures likely through beyond day 7.

 

Given the above but the lack of snow cover initially, have

forecast high and low temperatures mostly in the 20s to low 30s

by day and mostly teens by night. Coupled with breezy winds in

cold advection regime, minimum wind chill values look to be in the

positive single digits if not colder. The large scale pattern

continues to be one that generally appears unlikely to be

supportive of a major snow system through Saturday.

 

However, it is one that will likely have fast southeastward

moving energetic clipper systems over the central US and Midwest.

The most robust signal for one or more of these has been on the

Thursday night through Friday night timeframe, particularly on

multiple recent runs of the GFS (with some GEFS ensemble support).

It is still much too early to have much confidence in the track

and intensity of this clipper low(s), if it even materializes.

Have continued with low-mid chance PoPs for snow potential to

close the week. Even colder temperatures than what will occur Tue-

Fri are possible next weekend behind the potential clipper, much

colder than in current grids if most potent cold shot scenarios

come to pass. Should there be any snow cover across the local

area going into next weekend, then bitterly cold temps/wind chills

are possible.

 

Castro

Man that's a long write up

[Niko]

Chances are highs may struggle to reach the low 20s IMBY and lows in the S.Dt's.

[jaster220]

Man that's a long write up

No kidding. I think he's practicing up for GHD-3

[jaster220]

Chances are highs may struggle to reach the low 20s IMBY and lows in the S.Dt's.

Betta enjoy next two days..seems like gentle pattern transitions are so "yesterday's news"

[Niko]

He clearly states that the pattern is in no great shape for big storms, just clipper type systems. So, small accumulations to be expected, away from Snowbelt areas (where much more significant snows are expected).

[Niko]

Betta enjoy next two days..seems like gentle pattern transitions are so "yesterday's news"

I will.

[Niko]

No kidding. I think he's practicing up for GHD-3

Pretty good write-up, indeed.

[jaster220]

While not for mby, it is the first Hvy Snow threat outlined for SWMI

 

 

[Niko]

While not for mby, it is the first Hvy Snow threat outlined for SWMI

 

hazards_d8_14_contours.png

This will be a LES Special for snowbelt areas. Buffalo, NY and other surrounding areas will get buried in the coming days. All depends on wind direction, of course. UP, MI will do good also and other nearby locales. Pretty sure you will get in on some action as well.

[Niko]

Currently @ 38F under a partly cloudy sky and a very delightful evening out there.

[jaster220]

This will be a LES Special for snowbelt areas. Buffalo, NY and other surrounding areas will get buried in the coming days. All depends on wind direction, of course. UP, MI will do good also and other nearby locales. Pretty sure you will get in on some action as well.

Oh, I'll see white ground, but its a week from tomorrow before more than a coating to 1/2" happens on any one day or night here in Marshall. I don't mind tbh. Too much depth all at once insulates the ground. Small amounts allow the heat to get out so I'm not losing snow from the bottom up which happened with last Dec's 10 day blitz.

 

Oh, and Kzoo and west I'll see much more ofc!

[Niko]

Oh, I'll see white ground, but its a week from tomorrow before more than a coating to 1/2" happens on any one day or night here in Marshall. I don't mind tbh. Too much depth all at once insulates the ground. Small amounts allow the heat to get out so I'm not losing snow from the bottom up which happened with last Dec's 10 day blitz.

 

Oh, and Kzoo and west I'll see much more ofc!

Obviously! Hopefully, I can get some activity across the state.

[Niko]

My highs in the extended are brutal. Lucky to break 20F for highs. Brrrrrrr.

[jaster220]

My highs in the extended are brutal. Lucky to break 20F for highs. Brrrrrrr.

Remember, you said that you were glad to see AK shown above normal, cuz it meant you'd freeze your a$$ off! Just a reminder, hehehe :-P

[Niko]

Remember, you said that you were glad to see AK shown above normal, cuz it meant you'd freeze your a$$ off! Just a reminder, hehehe :-P

Bring it on boy!!!!

[OKwx2k4]

You know you're in a drought when your high temp anomalies run that much higher than the low anomalies for the month. Not expecting much improvement here until possibly late winter or even spring in my rainfall deficits.

 

 

 

In other news, the trough and expected cold still looks to gradually begin it's retrogression process over the last part of this month. Until that happens, the southern branch is largely dead. This pattern is still going great places though. Just taking longer to set up than I've been hoping.

 

 

This was posted tonight by a met named Larry Cosgrove in the weather America newsletter.

 

No doubt that many are skeptical of the consistent trend of the numerical models (which started on November 24) toward a mild West vs. cold Central/East alignment. Attempts by these same equations after all, have often failed miserably over the past two years in conveying both the approach and duration of cold weather. In fact, the last successful attempt by these schemes was in late January and early February of 2016 (the big East Coast snowstorm and Arctic intrusion)! But the fact that nearly every piece of guidance has shifted to a -EPO/-AO/-NAO styled alignment, with the venerable ECMWF series taking the lead in showing the most expansive, and long-lasting cold regime, gives me confidence that much of December will "feel like winter" from the Great Plains to the Eastern Seaboard.

 

If you are looking for some possible proverbial "bumps in the road' for a predictive cold wave, there are a few worth mentioning. If you accept the idea that this is a genuine La Nina episode, climatology favors warmth returning to the southern and eastern tiers of the nation at some point, probably sooner rather than later. The very warm character of the western Atlantic Ocean is an incentive for liquid, rather than frozen, precipitation types east of the Appalachian Mountains. Keep in mind that the snow field must extend below Canada in December, which would aid in maintaining a colder air mass profile below the Great Lakes. The cooler waters in the Gulf of Alaska would favor a return to an mA vortex there, thus pointing toward another run of mild, semizonal flow east of the Rocky Mountains. And then there is the matter of the analog outlooks, which show a strong shift to a cold West vs. warm East alignment after December 18.

 

In the end, however, the turn of the usually ultra-warm CFS scenario toward the colder-East forecast ECMWF weeklies was the clincher for me. That and the very steady nature of the 500MB flow, which does not change much in about six weeks of predictive time. The European ensemble package, mostly in concert with the Canadian series, shows one of the cA frontal waves delivering snowfall to parts of the Mid-Atlantic and New England states. When you combine that potential ice/snow coverage with expected deepening of frozen types in the Great Lakes region, then the prospect for at least 10 to 14 days of "true winter" must be recognized for the eastern half of the U.S.

 

The West could be in for another DJFM period marked by dryness and warmth. Recent precipitation trends have been very parched across the Great Plains as well, which may be a signal for ridge fluctuation toward the center of the U.S. I would not be surprised, for instance, that Texas and the south central states emerge occasionally into warmer air. But we also need to monitor what appears to be a signal on the computer schemes for a maintained subtropical jet stream through Mexico (seen in 2003-04, 2007-08 and 2008-09), which may act to shift colder air to lower latitudes while also providing chances for rainfall and rogue chances for ice and snow.

 

Let's Make America Wintry Again! But for that to happen, the sub-Aleutian vortex must stay put. Because any translation of that deep low to the Gulf of Alaska will make snow and cold lovers very sad in the East.

[Tom]

Expecting another fantastic day today as highs continue to torch into the upper 50’s. Today will be the day I put my lights up and clean up what remaining leaves that have fallen before winter finally arrives later this week. I’m hoping the ground freezes over, which it should, by the time the snow ️ arrives late in the week. The upper level 500mb pattern setting up near the lower GL’s is really impressive looking and pivots south of Chi which argues Lehs snowfall sometime Fri into Sat. The GFS at this range has been flashing impressive LES into parts of IN/MI and may be a huge hit for those folks. IndianaJohn and others in NW IN may need to prep their snow blowers!

[GDR]

Awesome weather this weekend hitting 60's today. One last mow and maybe a cold shot and clipper next week but I'm not holding my breath. Looks like the Great Lakes area has a better shot!

[westMJim]

After yesterdays high of 53° the temperature once again fell down to at least 26° at the airport (where they are reporting freezing fog) Here at my house I had a much colder low of 22° and here there was no fog but there is a lot of frost. I have a current temperature of 30° Now on to

Climatology for today December 3^rd    At Grand Rapids, MI

The average H/L for today is 39/27° (30 year average) and 38.1/26.0° (120 year average)

The record high was 65° in 2012 the coldest maximum was 15° in 1976

The record low was -6° in 1976 and the warmest minimum was 53° in 1998

The most precip that fell was 1.37” in 1982

The most snow fall was 4.0” in 1996 and the most reported on the ground at 7 AM was 11” in 1940

Last year the H/L was 36/34 and there was a trace of snow reported.

[Niko]

Gorgeous day today and another one for tomorrow......then, Arctic Express roars in late Tuesday. Today's high will be in the 50s. Average is 39/26F.

[Niko]

Couple of clippers down the road w numerous snowshowers throughout the week. Some light accumulations likely and definitely getting the ground white.

[Niko]

This Arctic Air will be getting colder and colder as the week progresses and onto the following week. I stand a shot at teens for highs and lows in the S.D's. Maybe, a storm can blow up outta nowhere and hammer some peeps on here.

[Niko]

Awesome weather this weekend hitting 60's today. One last mow and maybe a cold shot and clipper next week but I'm not holding my breath. Looks like the Great Lakes area has a better shot!

Especially, snowbelt areas. Even my area stands a fairly decent chance in getting some LES and I am on the other part of the state.

[Niko]

While not for mby, it is the first Hvy Snow threat outlined for SWMI

 

hazards_d8_14_contours.png

That heavy snow circle is right at your doorstep Jaster. Just a notch more east and BOOOOMMMM, your are in the game!!!

[Niko]

After yesterdays high of 53° the temperature once again fell down to at least 26° at the airport (where they are reporting freezing fog) Here at my house I had a much colder low of 22° and here there was no fog but there is a lot of frost. I have a current temperature of 30° Now on to

Climatology for today December 3^rd    At Grand Rapids, MI

The average H/L for today is 39/27° (30 year average) and 38.1/26.0° (120 year average)

The record high was 65° in 2012 the coldest maximum was 15° in 1976

The record low was -6° in 1976 and the warmest minimum was 53° in 1998

The most precip that fell was 1.37” in 1982

The most snow fall was 4.0” in 1996 and the most reported on the ground at 7 AM was 11” in 1940

Last year the H/L was 36/34 and there was a trace of snow reported.

My average H/L for today is 39/26. Its funny we have the almost the same average. I would have though your area would be slightly colder.

 

Find out when you get the chance if my area is colder than yours.

[jaster220]

29 deg diurnal spread (52/23) is pretty unusual stuff around SWMI, what with the Lk Michigan shadowing. To get a day of this occasionally is possible, but a stretch of days like this I don't remember tbh.

 

Raked the last of my leafs yesterday and could've mowed some of the grass again but said "screw it, it's Dec!"

[Jaycee]

That southwesterly ridge is going to be the death of me. Gosh what a travesty this thing has been for the plains. Unfortunately doesnt seem like its going to lose strength anytime soon.

[Andrew NE]

That southwesterly ridge is going to be the death of me. Gosh what a travesty this thing has been for the plains. Unfortunately doesnt seem like its going to lose strength anytime soon.

Your not kidding man, so frustrating to see model run after model run. Going to have to rely on some clippers I guess and hope a few can over perform.

[GDR]

It sucks and trends keep getting worse. I think I'll hope for some cold and purchase a snow maker! Any recommendations?

[OKwx2k4]

That southwesterly ridge is going to be the death of me. Gosh what a travesty this thing has been for the plains. Unfortunately doesnt seem like its going to lose strength anytime soon.

Yeah. Got to retrograde it or undercut it sometime. I know everyone is tired of patience but I still think this setup is exactly what most of us want to see east of the Rockies and north of I-40. These super cold retrogression patterns are really neat to watch.

[hlcater]

Since the 00z runs last night, I think this pattern has trended in a way such that those outside the lake belts may not actually see very much snow, and this cold dome may not be as persistent. Again, the Euro is bringing back in the warm air by the end of its run, and the GFS flattens out towards a bit more of a zonal look(which may not be too bad, all things considered). With the exception of fairly well advertised clipper at the end of this week, and maybe a few other weak impulses out of the NW, looks all quiet on the western front.

[NEJeremy]

[jaster220]

Stepped out to an unusual warm sunny situation. So much like spring here I think it's confusing. Heard a song bird singing like it was April. Don't remember that b4, not in December! This feels just like last Feb tbh. Begining to wonder about this winter. Not sure it will have the staying power of 13-14, even up my way. Might be looking at a two-faced season as some analogs produced?

[Madtown]

I am confused.....reading various afds it seems like mets are more on board with lasting cold than a few days ago...everyone in here was saying the same thing awhile back, now talking warm ups and short lived cold?

[Tom]

So we have the Euro/GGEM vs GFS regarding the late week Clipper.  Both Euro/GGEM lay down a couple inches and take the perfect track/pivot for E IA/IL/S WI/IN...while the GFS is to far east.  The Euro has been trending a weee bit stronger each run, nothing huge at this point but some good news nonetheless.

[Tom]

I do remember the year of '13/'14 clipper train the GGEM was the best to handle these features.  Can it be trusted this year???  We shall see and should be a good first test.

 

On a side note, I believe the reason for the ridge fighting back from the west into the Plains is due to a spike +NAO during the 9th-11th time frame.  Today's 12z Euro brings back a reinforcing shot of cold around the 10th back out into the Plains with a system traversing the base of the trough.  The -EPO is wrecking havoc with the modeling as was the case back in '13/'14 and '14/'15.