12/3-12/6 MW/GL snow event?

[Thundersnow12]

It might be time to revise my first call.

Id say so.

MKX

FRIDAY NIGHT THROUGH SAT NIGHT...FCST CONFIDENCE MEDIUM FOR HIGH

END ADVISORY TO LOW END WARNING EVENT.

MODELS COMING IN BETTER AGREEMENT WITH SHORTWAVE TROUGH AND

ASSOCIATED LOW PRESSURE TO MOVE FROM THE MID MO RIVER VALLEY ESEWD

TO THE OHIO RIVER VALLEY. MAXIMUM DIFF PVA TO FOCUS OVER SRN WI

WITH STRONGEST 850-700 MB WAA/FRONTOGENESIS TO FOCUS OVER FAR SRN

WI AND NRN IL. GOOD OMEGA VALUES IN A 150 MB DEEP DENDRITE ZONE

AS WELL. THUS QPF RANGES FROM AROUND 0.5 INCHES IN THE FAR SW CWA

TO 0.15-0.20 IN THE FAR NE CWA. IN ADDITION TO SYNOPTIC LIFT IS

LAKE ENHANCEMENT WITH 1000-850 MB FLOW BACKING FROM SELY FRI NT TO

NLY BY SAT NT. DELTA T/S AROUND 15-16C WITH INVERSION HTS OF 6-8

KFT. LES FLOW CHART GIVES ANOTHER FEW INCHES FOR THE LAKE COUNTIES

INCLUDING WASHINGTON/WAUKESHA. SNOW RATIOS ALSO TO BE FAIRLY HIGH

FROM 15-17 TO 1 BUT A LITTLE LOWER NEAR THE IL BORDER. SNOW TOTALS

OF 6-7 INCHES WEST AND SOUTH OF MADISON...AND OVER SE WI DUE TO

THE LAKE ENHANCEMENT. THE MIDDLE AND NRN CWA SHOULD SEE 4-5

INCHES. FLURRIES TO THEN LINGER SAT NT.

DVN

FRIDAY THROUGH SATURDAY ARE VERY INTERESTING WITH A SIGNIFICANT

SHORTWAVE DUE TO DROP THROUGH THE NORTHWEST FLOW...INTERACT WITH A

DECENT MOISTURE FLOW OUT OF THE GULF...AND PRODUCE WHAT LOOKS LIKE

OUR FIRST ACCUMULATING SNOW EVENT. THE WARM AIR ADVECTION WING

STARTS UP FRIDAY AFTERNOON AS THE SYSTEM MOVES INTO THE AREA FROM

THE NORTHWEST. TEMPERATURE ALOFT ARE COLD ENOUGH TO PRODUCE

SNOW...SO DESPITE WARM AIR ADVECTION PUSHING TEMPERATURES ABOVE

FREEZING IN THE SOUTH HALF THE EVENT SHOULD START AS SNOW.

HOWEVER...DURING THE EVENING HOURS THE WARM AIR ADVECTION WING

CONTINUES AND HAVE CONCERNS THAT THE SOUTHERN HALF MAY TURN OVER TO

SLEET OR EVEN RAIN...WITH THE SURFACE NEAR OR JUST ABOVE FREEZING.

FREEZING RAIN DOES NOT APPEAR TO BE A CONCERN WITH THIS EVENT WITH

THE WARM AIR ADVECTION WING NOT WARM ENOUGH AND THE SURFACE NOT COLD

ENOUGH...BUT THERE IS SOME POTENTIAL FOR A MIXTURE SOUTH OF

INTERSTATE 80 IF TEMPERATURES WARM ANY FURTHER ALOFT. EVAPORATIVE

COOLING EFFECTS MAY SAVE US FROM ANY ICE FRIDAY EVENING. WE WILL

HAVE TO WATCH THIS IN FORTHCOMING RUNS. ANOTHER ITEM OF

SIGNIFICANCE...THE MOST RECENT MODEL RUNS HAVE COME IN WITH HIGHER

QPF AND ATMOSPHERIC PW VALUES THAN ON PREVIOUS RUNS...WHICH MAY OR

MAY NOT WORK OUT. HAVE GONE WITH DRIER QPF THAN EITHER NAM OR ECMWF

RUNS IMPLIED...BUT WE WILL HAVE TO WATCH THIS. THESE HIGHER QPF

VALUES ARE SIGNIFICANT ENOUGH THAT WE MAY BE LOOKING AT A STRIPE OF

6+ INCHES OF SNOW FRIDAY NIGHT AND SATURDAY EVEN WITH RATHER WET

11-12 TO 1 SNOW-WATER RATIOS...AND A CLIMATOLOGICALLY NORMAL 13 TO 1

RATIO OVERNIGHT. THIS STRIPE WOULD EXTEND FROM SOUTHERN MINNESOTA

SOUTHEAST ACROSS NORTHEAST IOWA AND INTO SOUTHERN WISCONSIN AND

NORTHERN ILLINOIS.

[Thundersnow12]

18z NAM

[Moneyman]

Friday Night: Snow likely, mainly after midnight. Cloudy, with a low around 24. East wind around 5 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.

Saturday: Snow likely. Cloudy, with a high near 31. North wind between 5 and 15 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 3 inches possible.

2-5 inches

Milwaukee's grid forecast:

Friday Night: Snow, mainly after midnight. Low around 27. East wind around 5 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible.

Saturday: Snow. High near 33. East wind 5 to 15 mph becoming north. Chance of precipitation is 80%. New snow accumulation of 3 to 5 inches possible.

4-7 inches for them.

This could be a nice first little system.

[prinsburg_wx]

MPX

THE BIGGER STORY WILL BE THE STRONGER PACIFIC SYSTEM FOR FRIDAY

AND FRIDAY FRIDAY NIGHT. THE STANDARDIZED ANOMALY CHARTS FOR MOST

OF THE MODELS ARE SHOWING A WELL DEFINED BUT NOT EXCESSIVE

POSITIVE SIGNAL FROM THE PACIFIC ACROSS THE ROCKIES INTO SOUTH

CENTRAL MN FRIDAY AND FRIDAY NIGHT. NEARLY ALL THE AVAILABLE

GUIDANCE IS SHOWING AT LEAST A HALF INCH OF WATER EQUIVALENT

ACROSS PARTS OF SOUTHERN MN ENDING SATURDAY MORNING. THIS SEEMS

PLAUSIBLE GIVEN THE PW SIGNALS/FORECAST. THE SREF IS SHOWING

SLIGHTLY LESS AMOUNTS BUT MOST MEMBERS ARE IN GOOD AGREEMENT IN

FOR JUST UNDER ONE HALF INCH AT MSP. THE SNOW WATER RATIOS

INDICATED ON CARIBOU OUTPUT BE A LITTLE HIGH...BUT A EVEN 13-14 TO

1 WILL GIVE AT LEAST 6-7 INCH TOTALS GIBE THE QPF. IT DOES LOOK LIKE

THERE WILL BE A NW TO SE BAND OF FGEN FORCING SETTING UP FROM WEST

CENTRAL INTO SE MN. WILL HOLD OFF ON WATCHES FOR NOW...BUT HIGHER

RATIOS WITHIN THE SAID BAND COULD EXCEED CRITERIA. MUCH OF THE

AREA WILL BE LIKELY BE IN ADVISORIES.

[KokomoWX]

IND going with the more conservative 1-2" thoughts for now..

The best part for me is they have just 31/32 for the Saturday high now.

[Stevo6899]

NWs Milwaukee

If only that was the real location of the low. These local graphics can be misleading.

[Moneyman]

Anyone else checking out the 18z GFS? Tombo says at hour 60 there is a 1008 low pressure in southern iowa and that it is MUCH stronger then 12z. Interesting.

[Hoosier]

IND going with the more conservative 1-2" thoughts for now..

Although the HWO mentions moderate accumulations possible north of I-74.

[Chicago Storm]

Anyone else checking out the 18z GFS? Tombo says at hour 60 there is a 1008 low pressure in southern iowa and that it is MUCH stronger then 12z. Interesting.

It's wetter.

[AppsRunner]

It's wetter.

The sfc. Low still ends up further south than the 12z.

[Stebo]

18z block looks weaker and flatter, might be something to watch.

[Hoosier]

I'll field this one, 3 reasons why I would think it will be further north, 1 being models handling of clippers at this range to dig them too far south, yes I know its a hybrid so to speak but the origin of the energy is for a majority northern stream. Secondly as noted by you Hoosier the track of the 850/700mb lows are further north and don't match the QPF maps, its dangerous to just go by QPF maps knowing the lows are north. The 3rd and more important reason is that the block to the northeast is being forecasted too strong in my opinion, If it ends up being weaker which I would expect then you'd expect the clipper to track further north.

Fair enough. I didn't notice a significant discrepancy between the H85/H7 tracks and the precip shield but I may have overlooked it.

[Stebo]

Fair enough. I didn't notice a significant discrepancy between the H85/H7 tracks and the precip shield but I may have overlooked it.

Other than most of the QPF being along and south of those low tracks, normally its along and north.

[Hoosier]

Other than most of the QPF being along and south of those low tracks, normally its along and north.

It's hard to tell where the center is at times but for example, the 12z NAM appeared to take the 850 mb low from about Galesburg to Danville IL then IND and Cincy and the heaviest precip (snow) was along/north of that line. I guess I'm not sure what you're seeing?

[Tony]

Looks mighty nice. Aleking will have to make a minor adjustment to his thinking

[Stebo]

It's hard to tell where the center is at times but for example, the 12z NAM appeared to take the 850 mb low from about Galesburg to Danville IL then IND and Cincy and the heaviest precip (snow) was along/north of that line. I guess I'm not sure what you're seeing?

I'd say its a little bit north of that, especially on the GFS.

[csnavywx]

Other than most of the QPF being along and south of those low tracks, normally its along and north.

I normally use 300/500mb features for these since the surface low centers can be tenuous. 50-150 miles to the left of the vort max track is the traditional rule for best band of snow, though this can vary somewhat. At 300 mb, the left front quadrant is a good area for best snow totals. Using the track of the 850 low (NE Iowa to N-Cent IL) can be decent as well, and I like the -3 to -5C rule sometimes too. In this situation, it looks to be useful.

[Hoosier]

I'd say its a little bit north of that, especially on the GFS.

Just so you know, I'm not trying to fight here. You're saying the precip should be farther north but I'm not sure how far you're thinking. I mean, if you're sitting in Saginaw, Michigan right now and hoping this thing comes far enough north, that might be pushing it...

[Stebo]

Just so you know, I'm not trying to fight here. You're saying the precip should be farther north but I'm not sure how far you're thinking. I mean, if you're sitting in Saginaw, Michigan right now and hoping this thing comes far enough north, that might be pushing it...

No I know, I am skeptical there will be significant precip North of Detroit, but I do think that right now given the points I laid out earlier that the model has things too far south.

[A-L-E-K]

Looks mighty nice. Aleking will have to make a minor adjustment to his thinking

Current non sarcastic thinking is 2-5" LOT wide.

[WxMidwest]

This is starting to remind me of the power clipper either in 07-08 or 08-09, What winter was that?

[Ajdos]

This is what I meant by the LP and PRECIP not matching on the 12 and 18z.

[Ajdos]

This is starting to remind me of the power clipper either in 07-08 or 08-09, What winter was that?

Yup, that's the one.. It was 07-08.. Dec 16-17...

[Stebo]

Yup, that's the one.. It was 07-08.. Dec 16-17..

Not the same pattern though.

[MidlothianWX]

How much for Waukesha?

I am on vacation up here.

[Chicago WX]

Yup, that's the one.. It was 07-08.. Dec 16-17..

You got your dates wrong dude. Those images you posted are from the 2008-09 winter. There was a storm on Dec 16-17, 2007 too, but those images are not that storm...plus that wasn't a clipper.

[Stebo]

You got your dates wrong dude. Those images you posted are from the 2008-09 winter. There was a storm on Dec 16-17, 2007 too, but those images are not that storm...plus that wasn't a clipper.

The one you are thinking of in 2007 was definitely further north, DTW received 9.0. Although I am pretty sure that wasn't a clipper.

[Ajdos]

You got your dates wrong dude. Those images you posted are from the 2008-09 winter. There was a storm on Dec 16-17, 2007 too, but those images are not that storm...plus that wasn't a clipper.

Yeah, you're rigtht.. My bad.

[cyclone77]

Man it's going to be a close call for the QC. The GEM has shifted a bit north compared to the last few days, so I'm concerned with that. The 18z NAM also shifted a bit north. It seems like these types of clippers with a long WAA wing end up tracking a little further north at the last minute, as WAA is often underdone. I can see us getting hit by a brief band of snow along the WAA wing, only to remain dry the rest of Friday night. It's going to be a very close call though for sure. There's going to be a very steep drop off in amounts along the southern edge of the precip. For this reason I'd feel much more comfortable being on the northern edge of the snow band. My gut feeling places the heaviest snow from southern Minnesota though southern Wisconsin, and down towards Chicago and South Bend.

[Chicago WX]

The one you are thinking of in 2007 was definitely further north, DTW received 9.0. Although I am pretty sure that wasn't a clipper.

Dec 15-17, 2007 tracked along the IN/OH border, from Gulf origins. I remember it quite well...we got 10.5" here.