Dec 11-13 MW/Lakes/OV snow event part 4

[Justin]

I should add that any sleet that falls will help to compact the snow on the ground so perhaps not all the snow will blow around but a good deal of it will of course.

[cyclone77]

It seems almost impossible but the pressure gradient actually looks a hair tighter around the Quad Cities into Wisconsin at 12z Sunday.

40-50kts right off the deck at 925mb over a wide area. At 850mb winds are pushing 60kts.

[jbcmh81]

It would....but I would think the farthest south track that may verify if the sift continued would be along or a little south of the 80 corridor from Illinois to Ohio. Maybe something like 20 miles south of there....40 at most....but that would be a stretch I think.

I'd take that considering even the far northern tracks were still pretty good for snow around here. Then there'd be the worry about dryslot I guess.

[janetjanet998]

00 NAM seems to dump about .5 inches of frozen precip at ORD

alot more just north

If it is the north solution then chicago may hit the jackpot

[Justin]

Justin, what are you thinking up here in southern WI? Would the southern track increase the snow amounts forecasted?

Definitely- its looking better for you...only caveat is if the thing is so wrapped up it yanks a mid of mid level warm layer in and you get a lot of sleet but with the lift going on and the proximity of the mid level lows that should help offset that effect.

[jbcmh81]

Again assuming the 0z NAM is right, but there were places in the far NW part of WI that had near 1.5" QPF that's been reduced to 0.25" on this run. Of course I also assume that the offices up there weren't going exclusively with the NAM either. Snowstorms are finicky.

Man, I would hate to be in those areas now considering the trends. Would be even more ironic if JB ends up being correct after all the bashing he got today.

[msp]

mpx at 11-19 for the next 24hrs for e.p. heavy banding moving into mankato, we'll see what the next few obs there are like, but unknown precip at st. james.

[cyclone77]

I think the local NWS is going to have to up the snowfall amounts over the North half of our area and everywhere West of the river and likely upgrade to a WS Warning and then the Blizzard Warning will have to be dealt with. I think the signs are there this will end up a bit further South and could very well be wetter and the way the upper level features look I'd say a good amount of precip after mid day tomorrow very likely is almost all snow here. Those mid level lows will keep the column cool and aid in tremendous lift which only will aid in snow production.

With so much lift I wonder if some convective/thunder snow can break out. Since the RGEM/GEM have been the first to develop this further south solution I'm anxiously awaiting its arrival.

[cyclone77]

If it is the north solution then chicago may hit the jackpot

Starting to feel the same way. This thing may dump quite a bit of snow where it ends up pivoting, and right now the corridor from Dubuque, to Rockford, and particularly the north side of Chicago look very good IMHO.

[Hoosier]

Man, I would hate to be in those areas now considering the trends. Would be even more ironic if JB ends up being correct after all the bashing he got today.

I think he ends up being more right than wrong. He usually spices things up but this isn't your run of the mill snowstorm. East-west roads in particular (such as I-80) will be nasty given the wind will be mainly perpendicular.

[Justin]

With so much lift I wonder if some convective/thunder snow can break out. Since the RGEM/GEM have been the first to develop this further south solution I'm anxiously awaiting its arrival.

That is also a wildcard- you can't always pinpoint it exactly but I think its likely this produces thundersnow with the intensifying occurring over or near us. Someone will get way more than progged closer to us with less further north where the higher amounts are currently forecast...mainly North of MSP- GRB.

[MadTown]

if or when does MKE put up winter storm warnings instead of the watches

[Chicago WX]

LES signal for NW, N IN and SW lower MI is robust on the NAM. Not that it wasn't before, but wow.

[baroclinic_instability]

mpx at 11-19 for the next 24hrs for e.p. heavy banding moving into mankato, we'll see what the next few obs there are like, but unknown precip at st. james.

Definitely bright banding in there. Based on its orientation, prolly a little sleet then turning to freezing rain. Whenever auto obs report UP in these cases it is usually a sort of mix of sleet/freezing rain.

[TheWeatherPimp]

The IMBY questions and what do the NWS office questions get a little tiresome, just fyi

[MadTown]

sorry pimp first time i have didn't know it was an issue

[buckeye]

suck to have a ski trip planned for n. new england ski areas late weekend. is that +9 into Maine??? wow

[snowstormcanuck]

0z NAM at 18z/11

01z RUC at 18z/11

That subtle difference in sfc low position/track could end up meaning a lot.

[Justin]

This has certainly been one of the most fascinating systems I can ever recall seeing on models and how they evolve it. Definitely going to probably be some papers/studies written on this one.

[prinsburg_wx]

02Z

[cyclone77]

0z NAM at 18z/11

That subtle difference in sfc low position/track could end up meaning a lot.

Definitely a difference there. Seems like this is getting a bit slower as we go along, which allows more time to "dig".

[ILSNOW]

Milwaukee update

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI

833 PM CST FRI DEC 10 2010

.UPDATE...

CURRENT PRESSURE FALLS LOWEST OVER WEST CENTRAL IOWA. QUICK LOOK

AT THE BEGINNING OF THE NEW 00Z NAM FORECAST CONTINUES THE

SOUTHERN TREND OF THE SURFACE TRACK. 00Z NAM TAKES LOW ACROSS

FAR NORTHEAST IOWA BY 3PM SATURDAY THEN ACROSS KENOSHA AT 9PM

SATURDAY EVENING.

WINTER STORM WARNING AREA IS IN LINE WITH THE NEW NAM. FOR

TONIGHT NEW NAM TAKES IOWA PRECIP EAST TO ABOUT THE WESTERN EDGE

OF THE FORECAST AREA...THEN DIMINISHES THE PRECIPITATION BEFORE

REACHING MUCH OF THE FORECAST AREA. THEREFORE WILL HOLD OFF ON A

FREEZING RAIN ADVISORY BUT CONTINUE THE CHANCE OF FREEZING RAIN

LATE TONIGHT. NAM HAS A BAND OF AROUND 0.30 TO 0.40 INCHES OF LIQUID

COMING ACROSS THE FORECAST AREA IN THE ISENTROPIC LIFT DURING THE

DAY...WITH THE LONGER AND HIGHER QPF IN THE WARNING AREA. STILL A

WARNING POTENTIAL IN THE WATCH AREA FOR SUNDAY NIGHT WITH AROUND

0.20 TO 0.30 INCHES IN PRECIP WRAPPING AROUND THE STRENGTHENING

LOW.

PROBLEM WILL BE PRECIPITATION TYPE DURING THE DAY WITH 30 TO 40

KNOTS SOUTHERLY LOW LEVEL FLOW TAKING THE 0 DEG ISOTHERM TO THE

NORTHERN PORTION OF THE FAR FORECAST AREA BEFORE DYNAMIC COOLING

OCCURS.

OTHER PROBLEM WILL BE A FREEZING DRIZZLE POSSIBILITY BY SUNRISE

AS THE SOUTH WINDS AND MOISTURE INCREASES.

UNTIL OTHER GUIDANCE COMES IN CURRENT HEADLINES LOOK GOOD.

&&

[wisconsinwx]

I'm not going to post it here, but an update just came out for the MKE CWA. They aren't going to change anything, and still said the southerly flow brings a threat of mixed precipitation all the way north across the forecast area. Those darn southerly winds. I still have the feeling they'll change the southern bank of counties to a WSW.

[Hoosier]

LES signal for NW, N IN and SW lower MI is robust on the NAM. Not that it wasn't before, but wow.

This setup is pretty much textbook for massive inland penetration. I'm not sure how IND is going to handle the headlines given the synoptic event immediately preceding, but I think you can actually make a case for advisory amounts of LES in the northeastern part of the area.

[Justin]

Can't wait to see the new 00Z GFS... if that trends in line with the other models should be interesting to read more updates from the NWS offices.

[OceanStWx]

I think the local NWS is going to have to up the snowfall amounts over the North half of our area and everywhere West of the river and likely upgrade to a WS Warning and then the Blizzard Warning will have to be dealt with. I think the signs are there this will end up a bit further South and could very well be wetter and the way the upper level features look I'd say a good amount of precip after mid day tomorrow very likely is almost all snow here. Those mid level lows will keep the column cool and aid in tremendous lift which only will aid in snow production.

Once the snow starts I would guess we'll be straight to a blizzard warning, less confusion and fewer headlines to mess with. Plus if the 00z NAM is correct we're packing more than 28 mb across Iowa (again 10 mph for every 4 mb).

[msp]

Definitely bright banding in there. Based on its orientation, prolly a little sleet then turning to freezing rain. Whenever auto obs report UP in these cases it is usually a sort of mix of sleet/freezing rain.

yeah, which is what i assumed was the case. and no doubt that it's enhanced from bright banding.

fwiw, auto. ob of light snow in faribault and light rain in owatonna... 21/18 and and 25/25 respectively.

[TheWeatherPimp]

This setup is pretty much textbook for massive inland penetration. I'm not sure how IND is going to handle the headlines given the synoptic event immediately preceding, but I think you can actually make a case for advisory amounts of LES in the northeastern part of the area.

I'm not sure I have ever seen headlines in IND and ILN's forecast area for lake effect snow, but if the models are anywhere close to accurately depicting the set-up, I think it could be a good possibility. I would almost think it would be simpler for IND and ILN to cover their counties that will be affected by both synoptic and les snows with just one long duration advisory.

[OceanStWx]

I should add that any sleet that falls will help to compact the snow on the ground so perhaps not all the snow will blow around but a good deal of it will of course.

On the flip side though, the flash freeze will create a nice slick surface for the fresh snow to slide across Saturday night and Sunday.

[cyclone77]

Once the snow starts I would guess we'll be straight to a blizzard warning, less confusion and fewer headlines to mess with. Plus if the 00z NAM is correct we're packing more than 28 mb across Iowa (again 10 mph for every 4 mb).

What's interesting is that if you look at some of the models the QCA will be in sort of a dead zone as far as wind goes until after midnight tomorrow night. We may get a situation where we get snow to accumulate a few inches in a near calm environment, only to get blasted by very strong winds a few hours later.