Dec 11-13 MW/Lakes/OV Snow Event? Part II

[TheWeatherPimp]

Good read from one of the more reasonable mets at Accuweather, Joe Lundberg

If you love cold, and you live from the Midwest to the Gulf Coast and to the East Coast, then this is your kind of chart. Waves of cold, much like the big waves I saw Monday down at UCONN - Avery Point overlooking Long Island Sound and spying Race Rock Lighthouse in the distance through my binoculars.

So, it's really cold now. And it's going to get colder? Yep, that's the way it looks.

That begs the question: How do go from one cold wave to the next one?

Simple answer: A BIG STORM (or, as Henry might call it, a 'Big Daddy').

This is where it gets dicey. Since I've been off for a few days, I will readily admit I didn't look in any great detail at weather charts for a few days. Whether or not that's good or bad, I'll leave that for you to decide. Regardless, what little I've been able to pick up on in the past 12 hours or so is that once again, the trend, if there is any, is south with the storm track. not north. For snow lovers ahead of Christmas, you gotta love that news. If you're a retailer counting on seeing your store packed this weekend, with just one other weekend left before Christmas arrives, you're not so thrilled.

This storm will organize on the Plains Saturday. In advance of the storm, the deep eastern trough will fade, the old storm over northeast Canada will evacuate, and a couple of disturbances will flow through the pattern that will have the end result of pushing high pressure to the East Coast Friday night and Saturday.

In turn, what will be left behind is what we affectionately refer to as a 'stale' cold air mass. It is no longer anywhere near as cold as it was, and the direct evidence of that is the 850 mb temperatures that are forecast to be above freezing Saturday morning from southernmost South Dakota and parts of Iowa eastward to the Mason-Dixon Line,

And naturally, as the storm takes shape Saturday, out ahead of it, southerly winds will develop that will have the effect of trying to bring warmer air to bear from the south and southeast, and, over time, more moisture as well.

And here's the tricky part. The storm track is important, for it will have a bearing on how far north the warm air really gets this weekend. Then, perhaps even more importantly, will be the intensity of the precipitation and/or upward motion. If it is weak, then the boundary layer temperatures could well be warm enough for rain, not snow, though any given location with a surface temperature just below freezing is subject to an icy rain. But if we increase that upward motion and, therefore, the precipitation rate, this stale, cold, and, to start with, dry air could be cooled back enough to allow snow flakes to survive to the ground.

This 'battle', if you will, is going to be waged across the Ohio Valley into the central Appalachians. And it will come down to the two things I mentioned above. I don't have the answers right now, but you'd have to think that while there can be some mixed precipitation, or even plain rain, for a time on the front half of the storm as it takes shape, it will go over to all snow, and could snow pretty hard for several hours before ending from west to east.

East of the mountains, the debate is more if there will be any period of ice or mixed precipitation on the front side of the storm. The rest is rain, and there could be a lot of it, with strong southeast winds driving temperatures into the 50s along and to the south and east of the I-95 corridor.

One other thing could play a role in how this shakes out. The modeling is clearly implying that one storm will track into the Ohio Valley, but that a secondary will take over in time. If that happens, and it is far enough south, it could expand the area getting hit with snow as the storm reaches maturity later Sunday and Sunday night in and east of the mountains into northern and western New England. That's not an uncommon occurrence, and it may hold back the dam of warm air for a time over the interior of the mid-Atlantic and New England.

It will be a big storm following the big chill, followed by an even bigger chill. I likened it earlier today on one of my Q & A sessions to someone pulling the plug out of the bathtub, and all the water rushing in to the drain. That'll be the cold air behind this storm rushing in to fill the void left behind by the storm. Real concerns about record-smashing cold and damage to the citrus groves is in play.

And much like this current wave of cold will have an end to it (this weekend), the bigger chill next week will also ease during the second half of the week. But it's very likely to be followed by still another cold blast from the past.

And to think - winter hasn't even started yet!

[Baum]

Some thoughts earlier in the thread... Though they might be considered wishcast by a few

See ya's at 0z... For another episode of clueless.

I think you and Saukville are golden here....

[The_Global_Warmer]

Don't know really.

They put this in the map today. Low goes from S OK/N TX to here:

even with the perfect track for us, we won't be getting much if there isn't a more compact deeper UL system. I would probably expect 1-4 inches and expect it to get cold.

[OceanStWx]

Sorry for being M.I.A. for a while, the WFO is on lockdown to anything outside .gov sites due to virus issues.

I was glad the 12z Euro backed up my thinking and trended south, in agreement with its own upper air features. However, I'm disconcerted by its drastic shift back north. This scream phasing issues, and I haven't seen them, but I'm fairly confident the ensemble track will continue through the Ohio Valley.

It was interesting to note that the Euro was not handling the SLP fields correctly at 00z. The wind fields suggested a center 50-100 miles north of where the MSLP field placed it. I'm not surprised by a north shift for that reason, just not this drastic a shift. Regardless, a few of the models are showing some sort of inverted trough like feature that gives a decent (think lower end advisory) snow for Iowa and northern Illinois.

[JoMo]

Sorry for being M.I.A. for a while, the WFO is on lockdown to anything outside .gov sites due to virus issues.

I was glad the 12z Euro backed up my thinking and trended south, in agreement with its own upper air features. However, I'm disconcerted by its drastic shift back north. This scream phasing issues, and I haven't seen them, but I'm fairly confident the ensemble track will continue through the Ohio Valley.

It was interesting to note that the Euro was not handling the SLP fields correctly at 00z. The wind fields suggested a center 50-100 miles north of where the MSLP field placed it. I'm not surprised by a north shift for that reason, just not this drastic a shift. Regardless, a few of the models are showing some sort of inverted trough like feature that gives a decent (think lower end advisory) snow for Iowa and northern Illinois.

You should go back in hiding until this storm is over.

Good luck with the forecast up there.

[B-Rent]

For a little "wtf" action:

One IND TV station took the NW track completely off their maps this AM and showed 3 tracks taking the system right up the Ohio.

Another station put LAF right in a 8-12" bullseye.

=)

Sent from my Droid using Tapatalk

[OceanStWx]

I don't know if anyone has gotten a look at the Euro ensembles, but the chatter in the New England forum is that it is similar to its op run. Of course that is for the tail end of the run, and not the Ohio Valley.

Edit: Detroit to Watertown. Quite a shift north for the ensembles too.

[Moneyman]

Low goes from southern illinois to lake erie

Blizzard for Chicago

I got that in the New York City section.

Much farther northwest i'm guessing?

[A-L-E-K]

Low goes from southern illinois to lake erie

Blizzard for Chicago

I got that in the New York City section.

Much farther northwest i'm guessing?

Of what?, the OP or the general model consensus, i think you know the answer to both.

[Moneyman]

I meant the 0z euro ensembles. Is the 12z euro ensembles farther northwest then the 0z euro ensembles.?

[OceanStWx]

Low goes from southern illinois to lake erie

Blizzard for Chicago

I got that in the New York City section.

Much farther northwest i'm guessing?

The ensembles have more or less been tracking the surface low up the Ohio Valley (like PAH to ILN) for the last two days. Just when I thought I was out...

[JoMo]

I don't know if anyone has gotten a look at the Euro ensembles, but the chatter in the New England forum is that it is similar to its op run. Of course that is for the tail end of the run, and not the Ohio Valley.

Edit: Detroit to Watertown. Quite a shift north for the ensembles too.

Wow, well if the Euro wins out. I know what model I'm watching this winter.

[The_Global_Warmer]

that would good for me, pending the strength.

[OceanStWx]

Wow, well if the Euro wins out. I know what model I'm watching this winter.

It's not often you completely write off the Euro, so when it keeps pounding this one solution (which in particular happens to be significant for my CWA) you never really feel comfortable.

[WxMidwest]

The ensembles have more or less been tracking the surface low up the Ohio Valley (like PAH to ILN) for the last two days. Just when I thought I was out...

The "Goodfellas" of the Midwest.

[A-L-E-K]

my money says the euro mean take it to ohio somewhere (bold statement i know).

I'll jump on board. I'll do you one better and say through or a little north of CMH.

meh, weren't too far off.

15z SREFs rolling out soon, it had a few members at 9z that looked like they would evolve similar to the Euro solutions, it will be interesting to watch their trends to see what kind of support the Euro can gather.

[TheWeatherPimp]

Louisville AFD:

LONG TERM (THURSDAY NIGHT - WEDNESDAY)

...MAJOR STORM SYSTEM STILL ON TRACK TO IMPACT THE AREA THIS

WEEKEND...

HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST ON THURSDAY

NIGHT WITH A CLIPPER SYSTEM SKIRTING THE NORTHERN GREAT LAKES. A

LIMITED AMOUNT OF MOISTURE WILL SKIRT THE NORTHERN CWA AND WILL

LEAVE MENTION OF A CHANCE OF FLURRIES DURING THIS TIME. LOW

TEMPERATURES WILL GENERALLY BE IN THE MID AND UPPER 20S. FRIDAY IS

EXPECTED TO BE THE NICEST DAY OF THE FORECAST PERIOD AS SOUTHERLY

FLOW AND PARTLY CLOUDY SKIES YIELD HIGHS IN THE LOWER MID 40S ACROSS

OUR NORTHERN CWA AND NEAR THE 50 DEGREE MARK ACROSS OUR TENNESSEE

BORDER.

FRIDAY NIGHT - SATURDAY...

BY FRIDAY NIGHT...FOCUS WILL SHIFT TO THE DEVELOPMENT OF A MAJOR

STORM SYSTEM THAT WILL IMPACT THE AREA OVER THE WEEKEND. A SURFACE

LOW WILL SHIFT FROM THE LEE OF THE ROCKIES IN EASTERN COLORADO TO

THE SOUTHERN PLAINS BY DAWN ON SATURDAY. THE RESULTANT LOW LEVEL JET

AHEAD OF THIS SYSTEM WILL BEGIN TO TRANSPORT MOISTURE OVER THE WARM

FRONT EXTENDING FROM NORTH TEXAS ACROSS LITTLE ROCK TO JUST SOUTH OF

MEMPHIS. WILL HAVE TO WATCH HOW QUICKLY MOISTURE IS ABLE TO SATURATE

THE COLUMN AND PRECIPITATION BEGINS TO FALL IN OUR SOUTHWEST ON

SATURDAY MORNING. TEMPERATURES WILL BE NEAR THE FREEZING MARK AND

MAY HAVE TO WORRY ABOUT A QUICK SPURT OF FREEZING RAIN. AT THIS

POINT...TEMPS ARE FORECAST TO BE JUST ABOVE FREEZING AND LIKELIHOOD

OF ANY FROZEN PRECIPITATION IS LOW AT THIS TIME. HAVE RAINFALL

QUICKLY OVERSPREADING THE CWA FROM SOUTHWEST TO NORTHEAST DURING THE

DAY ON SATURDAY AS SURFACE LOW BEGINS TO STRENGTHEN AND LIFT NEAR

THE MIDDLE MISSISSIPPI RIVER VALLY BY SATURDAY EVENING. HAVE UPPED

POPS TO CATEGORICAL IN THE SOUTHWEST WITH LIKELY POPS ELSEWHERE

THROUGHOUT THE CWA. COULD EVEN SEE A RUMBLE OF THUNDER OR TWO IN OUR

SOUTHERN CWA ON SATURDAY AFTERNOON/EARLY EVENING AS SOME ELEVATED

INSTABILITY WILL BE PRESENT. OVERALL RAINFALL SHOULD BE AROUND AN

INCH FOR SATURDAY WITH AN OUTSIDE SHOT AT AN INCH AND A HALF IN SOME

PLACES.

SATURDAY NIGHT - MONDAY NIGHT...

SURFACE LOW LOOKS TO SLIDE SOMEWHERE ACROSS OUR CWA ON SATURDAY

NIGHT WITH FAVOR PUT TOWARD A COMPROMISING 00Z ECMWF/12Z GFS FOR

NOW. CANADIAN MODEL IS THE FARTHEST NORTH WITH THE LOW OVER SOUTHERN

INDIANA AND GFS ENSEMBLE MEAN IS FARTHEST SOUTH THROUGH NORTHERN

TENNESSEE. WILL HAVE TO WATCH THE TRACK AS THIS WILL ULTIMATELY

DETERMINE OUR CHANGEOVER TIME AND HOW MUCH QPF WE GET. HOWEVER...

ONE THING THAT CANNOT BE IGNORED IS THAT NO MATTER WHERE THIS

SURFACE LOW ENDS UP TRACKING THE BITTERLY COLD AIR BEHIND IT WILL

MAKE IT INTO THE REGION. THE PREFERRED SOLUTION OF THE GFS/EURO

FAVOR A QUICK CHANGE OVER TO ALL SNOW ON SATURDAY NIGHT WITH

SOUTHERN INDIANA SEEING SNOW FIRST. WILL MENTION A RAIN SNOW MIX IN

SOUTHERN THIRD AND EASTERN CWA TO ACCOUNT FOR UNCERTAINTY IN EXACT

CHANGEOVER.

CONFIDENCE IN THE SUNDAY THROUGH MONDAY PERIOD OF THE FORECAST IS

LOWER AS MODELS DIVERGE IN SOLUTION FROM THIS POINT.

EXPECT SCATTERED TO NUMEROUS SNOW SHOWERS TO LINGER ON SUNDAY AS LOW

DEPARTS TO THE EAST BUT LOW LEVEL MOISTURE LINGERS. HIGHLY AMPLIFIED

H5 TROUGH AXIS WILL SWING THROUGH THE REGION WITH NORTHWEST FLOW

FAVORABLE FOR UPSLOPE ENHANCEMENT AND A LAKE MICHIGAN FETCH. WILL TO

WATCH NORTHEASTERN CWA FOR LINGERING SNOW SHOWERS THROUGH MONDAY

NIGHT. OVERALL...STILL EXPECTING AROUND 1 TO 2 INCHES OF SNOWFALL

FROM LATE SATURDAY NIGHT THROUGH MONDAY...WITH OUR SOUTHERN INDIANA

COUNTIES POSSIBLY SEEING 3 INCHES.

OF CONCERN WILL BE SURFACE WINDS ON SUNDAY AS NORTHWEST WINDS OF 20

TO 25 MPH WITH OCCASIONAL GUSTS TO 30 TO 35 MPH WILL BE POSSIBLE.

ANY SNOW THAT IS ABLE TO FALL WILL BLOW AROUND AND COULD CREATE

WHITE-OUT CONDITIONS AT TIMES. ALSO...WITH RAPIDLY DROPPING

TEMPERATURES AS ARCTIC AIRMASS BLASTS IN...WILL HAVE TO WATCH WIND

CHILL VALUES THROUGH WEDNESDAY MORNING. THESE HAZARDS WILL BE

MENTIONED IN THE HWO.

EXPECT A VERY SMALL DIURNAL TREND ON SUNDAY AS STRONG COLD AIR

ADVECTION COMBINES WITH HEAVY CLOUD COVER. TEMPS SHOULD NOT MAKE IT

OUT OF THE MID 30S. BY SUNDAY NIGHT...THE MERCURY IS EXPECTED TO DIP

INTO THE LOW TO MID TEENS WITH A FEW SINGLE DIGITS ALSO POSSIBLE.

MONDAY WILL NOT SEE HIGHS OUT OF THE MID 20S WITH MONDAY NIGHT LOWS

MOSTLY IN THE SINGLE DIGITS TO LOW TEENS. WIND CHILL VALUES ARE

EXPECTED TO BE THEIR COLDEST ON MONDAY AND TUESDAY MORNINGS WHERE A

RANGE FROM -5 TO 5 ABOVE ZERO WILL BE POSSIBLE.

[Stebo]

Well the Euro is interesting, it certainly helps confidence

[The_Global_Warmer]

From a poster on our local board. The euro drops 3 inches on my area in blizzard fashion.

lock it in, I am done, 3 is fine with me.

[Chicago Storm]

[JoMo]

GGEM ensembles would support that.

[A-L-E-K]

Just south of Detroit was my thought yesterday, so it's nice to see the euro ensembles in agreement and yes, that's very nice.

[Tony]

That could be some serious LES for this side of the lake!!

[A-L-E-K]

That could be some serious LES for this side of the lake!!

Meh, not sure about the thermals and the trajectory doesn't imply anything all that organized, but it would put out a nice lake enhanced defo band.

[The_Global_Warmer]

Remembre the Euro ensemble mean goes from the OK/TX border to S. IL to that destination in 24 hours...

the track is way different from the OP early on.

[WxMidwest]

With them winds, could be LES and Lake Enhanced Snow all the way back into further West Counties of LOT.

[A-L-E-K]

Remembre the Euro ensemble mean goes from the OK/TX border to S. IL to that destination in 24 hours...

the track is way different from the OP early on.

the OP has a low on the TX/OK border at hr 72.

[ArmyGreens]

With them winds, could be LES and Lake Enhanced Snow all the way back into further West Counties of LOT.

Shoot! We may even pick up a few here as we have all week!

[Chicago Storm]

Remembre the Euro ensemble mean goes from the OK/TX border to S. IL to that destination in 24 hours...

the track is way different from the OP early on.

I'm willing to bet there is a SLP up north to based on the elongated look to the pressure fields.

[A-L-E-K]

18z NAM (I'll myself here) Looks like it wants to have a more dominant northern 850 as well, real good hit for Southern Minn / Northern Iowa