2/10/07-2/13/07 FCST: Midwest (WINTER PRECIP)

[Robert Dewey]

However, if this low pressure system tracks 20-50 miles further south than anticipated, the northern fringes of your maps are going to get a dusting at best.

That is correct. Storm track to the north means southern edges get cutoff, storm track further south means northern edges get cut off.

You also need to remember that 0.25 inches of QPF at a 30:1 snow ratio is around 7 inches of snow... So while areas to the north only receive 0.25 inches of QPF at 7 inches of snow, areas further south will need 0.70 inches of QPF to attain that same 7 inch snowfall total.

As of the 12Z models, KPIA to KDTW will likely see the worst of the storm as a combination of wind and fluffy snow create low visibility and cold wind chill values.

 

[Jesse Risley]

As of the 12Z models, KPIA to KDTW will likely see the worst of the storm as a combination of wind and fluffy snow create low visibility and cold wind chill values.

Well if that holds true it looks like Brandon and I will see another snow today tomorrow and/or Tuesday! However, I'm guessing it's gonna be another long school year that doesn't end until after Memorial Day. This is starting to remind me of the winter of 1993-1994 in North Central IL. Long range models are also forecasting an active March too.

It also looks like the KPIA-KDTW area would be most impacted by a jet streak..so I'm guessing your snow totals could be more accurate than current WSW predictions if that holds true.

 

[Joel Wright]

I think the heaviest snows will evolve out of the big surge of moisture moving north late Monday night and especially Tuesday. A large area of heavy rain and thunderstorms will develop Monday night down south near the organizing surface low, and bulge north rather rappidly later in the night into the colder air in place to the north and reinforce the ongoing snowfall. I think the heaviest band will set up from eastern IL into northwest Ohio. This area could see up to a foot of snowfall.

Snow to water ratios will likely be near 10:1 in this heaviest band. To the north the ratios will be higher, say up to 20:1, but moisture will be much less impressive and the precip will be fighting dry air trying to fight in from the northeast.

I think the "jackpot" band of snow will line up roughly from Lafayette to Fort Wayne IN, to Bowling Green OH. 10-12" first guess along this line.

Further back to the west in Illinois, Missouri, and Iowa, moisture looks to be lacking a bit, but upper dynamics and slightly higher snow to water ratios will help offset that a bit I think. There is a closed low above 700mb, so that's good. I think the snows in these areas will be fairly "bandy", with large areas of just light snows in between.

Time will tell and I'm looking forward to later model runs.

 

[Dan Robinson]

Looks like yet another ice event for winter 06/07 taking shape, along the Ohio River this time. I almost don't want to look at models until the day of the event - it's all where the freezing lines at the surface and aloft set up, almost impossible to pinpoint now.

Just a side note - we have a real 'weather bubble' here, called the warm wedge. From the looks of the NWS watch/warning map, the warm wedge is giving Charleston, WV a bit of 'Norman, OK syndrome' as the only location in the storm swath outside of the winter storm watches.

 

[Robert Dewey]

FWIW, KIWX is says that areas in the watch should expect in excess of 12 inches. Their AFD states 12-16 inches, locally higher. It will be interesting to see how this evolves. The 18Z NAM is further northwest than the 12Z run, and the 18Z GFS is pretty close to the 12Z GFS (perhaps a touch further southeast with the QPF).

 

[rdale]

You also need to remember that 0.25 inches of QPF at a 30:1 snow ratio is around 7 inches of snow...

That ratio might be a little high given cold temps in place. I'm intrigued by the northward motion but not ready to ignore the dry air hanging around and being advected in on the northeast winds...

 

[Brandon Sullivan]

Wow. This system is slowed by the models yet again! Honestly though... I still see the same effects. Note that some WFO trimming the snow totals due to a slight temperature inversion. Thus, could see some mixed precip.. How much however remains to be told. I am still confident that the area should see warning criteria snow.. Blizzard conditions will be marginal.. My normal model site seems to be down. So I am using a new model source.. so interpretations a little different. After seeing the new models.. I do agree with Joel on the heavier snows in E IL.. This most likely due to the more southern track the storm is forecast to take. Now dipping into N Texas rather than going through central OK. Looking at the SREF, that prediction seems to be right on. It has changed before so I wont be surprised to see it change again.. Well be around watchin it.

 

[david diehl]

Decided to make an outlook map outlining where I think the heaviest snow will setup. Basically, I think somebody in that zone will see up to two feet of snow... With several locations hitting 12 to 18 inches. The outlined area is broad, which is a good indication of uncertainty; I don't expect that entire area to be affect, rather a more narrow band will likely setup somwhere within that zone.

I aggree with you on that, Even Northern Indiana has everything going up calling for up to 15 inches for my area tomorrow through tuesday evening.
not sure if I can post the link to the Page in this forum, so I Will hold off till I know

 

[Robert Dewey]

Latest 00Z NAM continues the northward trend... It looks like quite a storm will setup. I'll post a write-up in the morning.

 

[Danny Neal]

It seems like I am caught in the middle. I don't know if thats a good thing or a bad thing. Snow Advisory to my north tonight, Winter Storm Watch to my south. City of Chicago currently off scott-free right now. I am more interested in the possible lake effect band the south side of Chicago and NW Indiana might be getting. East-Northeast winds are expected to blow up to 35 mph. Everyone here and in the media are mentioning a mainly south of I-80 snow event and that will be the case if the Storm continues on its current forecasted track. Well now I have given up on all hope of the storm track to move 50 miles to the north and give me 8-12 inches of snow. Alot can still change but, I have seen this types of storms come and go and they usually hold true to what is currently forecasted. I have focused on some lake effect for the City of Chicago, South Subs, and NW IN eventually later on Tuesday night into Wednesday. Anyone else concerned about this? I know this is mainly focused about the main system so I am kind of skeptical. Will it be historical? hell no! But maybe a nice band can form over the southside and drop 8-10 of its own! Hmmm?

 

[rdale]

Inot sure if I can post the link to the Page in this forum, so I Will hold off till I know

This forum is for YOUR forecasts, we all know how to get NWS info... Go ahead and come up with one yourself and/or a graphic and link that.

NAM still off the wall for southern MI with a foot in Lansing and Jackson, and the WSI version of the WRF (for which we pay a lot of money) has two feet for most of the area on Tuesday! CTRL-ALT-DEL and try again ;> I'm still on the GFS side with 4" in Lansing and 8-10" closer towards Toledo.

 

[Robert Dewey]

This forum is for YOUR forecasts, we all know how to get NWS info... Go ahead and come up with one yourself and/or a graphic and link that.

NAM still off the wall for southern MI with a foot in Lansing and Jackson, and the WSI version of the WRF (for which we pay a lot of money) has two feet for most of the area on Tuesday! CTRL-ALT-DEL and try again ;> I'm still on the GFS side with 4" in Lansing and 8-10" closer towards Toledo.

The NAM has been right more often than not this winter... I just remember a few instances where everyone said "well, the NAM is out to lunch with this really intense northwestern storm" only to see that it was in fact right. Two feet might be stretching it, but it wouldn't totally catch me off guard.

I'm having a lot of issues with the NCEP page - I really wish I could see the storm total QPF's and the lastest 00Z GFS that's rolling in. Someone needs to CTRL-ALT-DEL their site and hit reboot.

 

[rdale]

It has had mixed success on winter storm paths - but ALWAYS been way too high on big QPF events. Re: NCEP --

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
1005 PM EST SUN FEB 11 2007

IN SUPPORT OF THE WINTER STORM RECON PROGRAM THE NOAA G-IV
IS FLYING OVER THE PACIFIC IN AN AREA FROM 25-35N AND
132-150W. FOR THE START OF THE 00Z CYCLE RECEIVED 14
DROPSONDE REPORTS.

FOR THE PAST SEVERAL DAYS HIGH DEMAND HAS PUSHED NCEP WEB
SERVERS TO CAPACITY. JUDGING BY RECENT DAYS THE HIGH DEMAND
PERIOD RUNS FROM ABOUT 0400Z UNTIL 0530Z. DURING THIS
PERIOD USERS HAVE HAD DIFFICULTY ACCESSING NCEP WEB SITES.
A SIMILAR PERIOD HAS BEEN OCCURRING FROM ABOUT 1530Z UNTIL
1730Z. NCEP HAS PLANNED UPGRADES TO INCREASE CAPACITY
WITHIN THE COMING WEEKS....THANK YOU FOR YOUR PATIENCE...

 

[Brandon Sullivan]

System still moving slower than expected this morning.. But none the less is heading our way. Warnings coming out left and right... Well.... I believe the moderate to heavy snowfall totals will be there.. Pretty confident in that aspect. Definitely believe snow totals will be higher where precip can be all snow. All in all.. My main concern now is the blizzard like potential.. SKEW T's depict the following.... (All Wind Speeds Are forecast surface Winds) WRF 7 MPH GFS 17 MPH NAM 17.... Note that these speeds are during the storm, they will pickup upon the departure of the storm.. As the pressure gradient tightens... Will have to watch how these go, and how the system evolves.. I will start a NOW thread shortly.

 

[Robert Dewey]

06Z NAM and GFS on track, trending slightly stronger yet again. Not much change in the QPF fields with both models indicating widespread 0.50 to 0.75 inches across lower MI, with 0.75 to 1.00 over northern IN and northwestern OH.

The 03Z SREF shows a maximum of 1.25 inches all the way up to I69, which carries a 30% chance of happening. The 0.50 inch amounts carry a 90% chance. I would assume that gives areas of southern MI a total of 0.85 inches of QPF at a 60% chance. The SREF 3 hour snowfall output shows quite an intense band setting up over MI, actually providing more snow than what areas of IN/OH are expected to receive as the deformation zone really ramps up. Even the weakest SREF member still indicates 12 inches over extreme eastern/southeastern MI. On the other hand, the strongest SREF member (or the strongest SREF member for each 3 hour timeframe?) outputs storm totals of nearly 30 inches southeast of LAN to FNT.

Taking the averages of the two extremes yeilds areas of 20 inches. Looking at the cyclone tracks for the SREF, there is quite a variance in potential storm strength with a 100 mile track difference.

With the winds that are expected to accompany the system, anthing over 8 inches has the potential to really distrupt things. Anything over a foot, and we're looking at dangerous conditions... 18 inches or more and we'll be looking at impassable roads.