1/13/07-1/15/07 FCST: OK / KS / MO / IA / IL / WI / IN / MI (WINTER PRECIP)

Looks like the GEM is continuous with it's previous runs. It looks pretty similar to the NAM as far as I can tell (the graphics make it hard to tell). I'm going to say the GFS is an outlier, but that could change in a run or two when ALL models are showing nothing LOL
 
Looks to be close, but some areas in Oklahoma whether it be Norman, Ada, or Broken Bow will be out of power for a few days to a week. I see at least one spot getting a good 1-2 inches of ice out of this storm.

I'll be keeping as many updates as possible on the event on my site, but on Sunday the power might go out for good if the models verify.
Here's the link, but I'll get more up as the storm progresses:
http://www.stormgasm.com/1-12-07/1-12-07.htm
 
The 12Z NAM continues the weakening trend, getting closer and closer to the GFS. However, I'm still interested because the -10C 850MB isotherm is hanging around an area with 0.75 inches of QPF... I'm thinking snow ratios could be north of 20 to 1, which would lead to some pretty decent accumulations.

As Joel (I believe) mentioned before, alot of moisture seems to be getting stuck south of the region along the boundary (or just south of). The model might be overdoing QPF amounts in that region (and all of the lift that goes along with it), so some of that moisture might in fact make it further north. The problem is, of course, that the air is really cold just north of the boundary, so it's hard to get massive amounts of QPF (this could explain the lack of QPF).

I remember a couple years ago when an Alberta Clipper dropped southeast with models indicating around 0.50 inches of QPF... With such a cold airmass in place, that equated to roughly 10-12 inches of snow for my area (it was quite a surprise storm).

Still, the heart of this system is 72 hours out so there's plenty of time to play with strength and location. It's just hard to believe this system doesn't wrap up more given the intense baroclinic zone with the energy passing overhead. Of course, one of the main shortwaves is stuck way up in Canada right now, so I would venture to say it's not well observed at this time.
 
The trend for a weaker storm continues as each run comes in. It's now looking more like an advisory criteria snow system rather than warning. I'm with Robert in not understanding how such a strong baroclinic zone and decent troughing can't spin up some sort of a storm of consequence.

Snow ratios will be high, and that will help somewhat. However, model QPF is on a downward trend so that's only some consolation.
 
Eastern IA winter weather update

An active winter weather pattern along with much colder temperatures will affect the area over the next several days. In addition, the potential exist for the season’s first significant snowfall event beginning Saturday evening and lasting through the first part of Monday.

Cedar Rapids:
Today: cloudy with flurries. Saturday, snow will start at 7 PM and will become moderate to heavy for a brief period during the evening before tapering to flurries by midnight. A second period of snow will start at 1 PM Sunday and snowfall will last through 8 AM Monday. Total snowfall: 4â€￾ (Eastern Iowa airport), 1â€￾-3â€￾ (northern Linn Co.).

Iowa City:
Periods of very light snow through mid-afternoon today, but this will not cause any travel problems. Saturday, snow will start at 6 PM and will become moderate to heavy for a brief period during the evening before tapering to flurries by midnight. A second period of snow will start at 1 PM Sunday and snowfall will last through 8 AM Monday. Total snowfall: 7â€￾.

Discussion:
Large-scale positively-tilted trough dominated the western half of the continental US while a cutoff H5 low was located over NV. At the surface, a strong arctic cold front had pushed south and east through the area and was located along a St. Louis to Chicago line at 16Z. In IA, some light precipitation was falling in south central into south eastern parts of the state, and current radar trends and guidance suggests that this precipitation should stay south of I-80 in eastern IA.

Through the period, the closed H5 circulation will open up and eject ahead of the main trough, and this wave will affect the area during the day Sunday. While the positive tilt of the overall trough will hinder strong moisture transport north into IA, this shortwave will provide a window of WAA through the early portions of Sunday. GFS has been most consistent with this system while the 12Z NAM has come into decent agreement. Both models now indicate a compact lead wave which will lift through the area Saturday while giving the area a short-duration period of moderate snow. SREF ensembles suggest 1.5â€￾ accumulated snowfall between Des Moines and the Qaud Cities, while the NGM and RSM ensembles are lighter with QPF. The main event starts Sunday afternoon in association with the primary wave, and the precipitation forecast is difficult given a sharp cutoff in intensity from south to north. As is often the case with these winter storms that have strong dry flow from the north in association with an arctic airmass, the precipitation will have a sharp cutoff along the northern edge of the system. Weather models generally don’t handle this dry air advection well, and it is generally necessary to adjust the northern end of the QPF accordingly.

In summary, this system will be somewhat moisture starved in IA owing to the orientation of the surface front with the upper-level flow. As a result, much of the moisture will stay well to our south in MO and southern IL, where a significant ice storm will take place. Nevertheless, a long-duration event coupled with rather large snow to water ratios should result in several inches of snowfall in east central IA.

[FONT=&quot]- bill[/FONT]
 
Well, I'm at the point now where I'm just going to stop watching this system. Unless something drastic changes on the 00Z run, I'm not too confident in a significant winter storm for areas downstream in the Great Lakes. The trend in the models is to be further south and weaker.

I'll keep my fingers crossed and hope that the NAM/GFS are missing something, but I'm doubtful.
 
Wow. Even though the snow aspect of this storm is somewhat unimpressive, the ice aspect sure isn't!

Looking at the models, a narrow ribbon from south-central OK up through central MO look to be getting a pretty thick coating of ice over the next three days. The southward push of the surface boundary will begin to slow, while warm air advection aloft will remain, and even increase somewhat at the same time. I think Missouri may end up with the jackpot for most ice accumulation. The area around Columbia down towards Joplin and Springfield most notably. Okalahoma is a bit tougher, as the cold air will be getting slowly deeper there as time goes on, causing ice pellets and even snow to eventually mix in where freezing rain is falling now.

This is actually somewhat reminiscent of the New Year's storm in NE, with wave after wave of moderate to heavy rain falling into subfreezing air over a period of three days. Warm air will try to make a comeback, if you will, later saturday night into sunday in Missouri in response to the strongest of the waves ejecting out of the base of the trough. This should keep the 0° isotherm firmly in place.

Forecasting ice events is very challenging to say the least. For significant ice accumulations to fall, there has to be a perfect balance between the two airmasses for a decent period of time. It sure looks like this is what's in fact going to be taking place especially in Missouri in the next three days...
 
I lied, I'm still watching things LOL

18Z NAM bumps up QPF slightly more across my area (around 0.80 inches of liquid). That would be all snow with pretty decent ratios expected.

NWS DTX is backing up what I said earlier (posting an excerpt since it applies to my earlier thought):

EVEN THOUGH THE MODELS SEEM TO BE CONVERGING ON A SOLUTION...STILL
LEARY WITH MOST OF THE PLAYERS NOT BEING SAMPLED PROPERLY OVER THE
PACIFIC AND NORTHERN CANADA AND WOULD NOT WANT TO LET OUR GUARD DOWN
FOR A MORE SIGNIFICANT STORM.
 
Here in cntrl Okla. much of the precip. especially here in northern Canadian county has been sleet. Based on the 18Z soundings, the cold air has deepened a couple more thousand feet and temps. currently running around 22F here in Piedmont.

My guess is HOPEFULLY the depth of cold air will remain or get deeper yet lessening the chances for precip. to change to all liquid. I suspect with the next shortwave ejecting out into the plains later tonight.. warm air advection maybe more pronounced, so freezing rain chances may increase.

We have a cord of firewood, the generator is ready to go in the worse case scenario.. but my hunch is at least north of I-44, we may be dodging the icy bullet and deal with a few inches of sleet instead... which is mighty fine by me. After the 2002 ice disaster, I have no desire to see the likes of that again.. thank you very much!

Rocky&family
 
Wichta Falls area

Temp has dropped to 32 as of 3pm and ice already has formed on Cars and Trees. I can hear the ice crackling in the trees now. Also the freezing rain is mixing with ice pellets. Roads OK so far but bridges and overpasses may be slick for sure. I would be very careful on the Overhead freeway here in Wichita Falls if they havent already shut it down. They may wait to do so after sunset. If they dont shut it down.....Ill have some serious questions for out road crews here. I also noticed no type of chat or gravel has been layed down.....Why do they wait till ice actually forms?
 
I thought you would be back Robert. ;) lol. Im gonna stick with this one. Accums. of 4-8 inches seem the most probable per local calculations and the Garcia Method. Believe snow ratios could be as high as 15-20:1 on Sunday I have just been posted under an ICE STORM WARNING and after talking with NWS am anticipating a Winter Storm Watch/Warning tommorow to cover the snow accums.. Already have about 3 tenths of ice accumulation, and the NWS said in the ICE product that a few isolated spots in my area could see up to an inch of ice!! WOW!:eek: :eek: Still a couple chances for models to change.. but Im looking for a lot of problems here.
 
I thought you would be back Robert. ;) lol. Im gonna stick with this one. Accums. of 4-8 inches seem the most probable per local calculations and the Garcia Method. Believe snow ratios could be as high as 15-20:1 on Sunday I have just been posted under an ICE STORM WARNING and after talking with NWS am anticipating a Winter Storm Watch/Warning tommorow to cover the snow accums.. Already have about 3 tenths of ice accumulation, and the NWS said in the ICE product that a few isolated spots in my area could see up to an inch of ice!! WOW!:eek: :eek: Still a couple chances for models to change.. but Im looking for a lot of problems here.

Yeah, I'm generally speaking of the Great Lakes region (IN/MI)... Areas further south/west have a better chance of verifiying with the model data since the "time until kickoff" is a lot closer. Further downstream in my area, there's more bust potential.

Anyway, the NCEP take on the 12Z model runs state there are some pretty big errors with the initialization. They also mention that the GFS might be contaminated by convective feedback. The 18Z run of the GFS is a little more organized at 500MB compared to the 12Z, but since the 18Z models are in fact based on the 12Z upper air data, they are still subject to error.

I'm somewhat with DTX on this - I wouldn't be surprised to see this storm "return". My guess would be that it could "return" in the 24-36 hour timeframe when things are starting to pull together. A wishcast more than anything, but hey - it's a boring season thus far. EDIT: for me at least ;-)
 
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The latest 00Z NAM is more intense than the previous few runs, and the 00Z GFS is now showing more of a closed solution (at least at 850MB) over the Great Lakes region. This could be the storm beginning to "re-appear". Still waiting for the reast of the GEM to come in.

IF the system really bombed out, the SFC low would probably track much further north and west. The flatter the system is, the further south... So, I'm in a "damned if you do, damned if you don't" situation as always. If the storm bombs out, it passes to the west... If it weakens too much, it passes to the south. Not saying the storm will do either, but that's just a personal observation.
 
This is the best poker playing Winter Storm I've seen. It just doesn't want to show it's hand until Sunday. The models haven't been able to figure this thing out for the past week. Looks to be more of an Ice Storm than snow attm. If it does bomb out; then southern WI will get a nice surprise on Monday morning.
 
Cobb method showing forecast ratios of from 12-15:1 With PWAT values at about .45 - .50 then we could wind up with 6 +. Still believe system is underdone.. And look for banding snow.. Will have to wait.. But the trend could be to shift the heaviest area of snow northward
 
6Z NAM for Lansing (Cobb method): 2" tonight, 8" tomorrow
6Z GFS: 0.2" tonight - ABSOLUTELY NO QPF TOMORROW NIGHT!
12Z NAM: 0.2" FZRA tonight, 3" snow tomorrow

Wow. I'm quite surprised to still be seeing this dramatic of difference only 36 hours out... Glad everything is dropping tonight's QPF, I really didn't see that being much of a snowmaker in the first place.

Now the 12Z GFS is continuing the southerly and much weaker QPF fields as the previous runs - no more hyping this storm (at least for today.)
 
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The GFS seems to be the odd man out (QPF to the south seems almost TOO heavy over a widespread area), also tracking the low too far south... Meanwhile, the NAM might be too far north, but the 12Z GEM is pretty similar. For what it's worth, the 12Z NGM is between the GFS and NAM, but it has a better precipitation shield - perhaps the NGM isn't stopping the moisture feed northward like the other models (not sure).

EDIT:

FSL 13km RUC actually further north than the NAM with a really nice precipitation field (again, not showing the 5-7 inch QPF amounts seen on the GFS and NAM to the south). This is probably too far north, but the FSL RUC has caught on to a lot of trends in the past (the past winter storm that affected southwestern lower MI and parts of WI -- that was projected to affect far southeast lower MI, but the FSL RUC caught the northward trend.).
 
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I'm siding with the NGM. It's typically the driest model, and it delivers an impressive amount of QPF on both sides of the arctic boundary. The GFS (and even NAM to some extent) just look ridiculously dry beyond 30hrs in the cold sector. I look for both of these models to change in future runs.

Even though the low pressure isn't closed above 700mb, there is still a lot of lift being generated near and ahead of the trough which should squeeze out some decent snows.

Snow to water ratios will vary depending on location within the snowband. Areas on the northwest side of the band will likely see the ratios exceed 20 before the snow ends.
 
I'm siding with the NGM. It's typically the driest model, and it delivers an impressive amount of QPF on both sides of the arctic boundary. The GFS (and even NAM to some extent) just look ridiculously dry beyond 30hrs in the cold sector. I look for both of these models to change in future runs.

Even though the low pressure isn't closed above 700mb, there is still a lot of lift being generated near and ahead of the trough which should squeeze out some decent snows.

Snow to water ratios will vary depending on location within the snowband. Areas on the northwest side of the band will likely see the ratios exceed 20 before the snow ends.

Yeah, that's my general thought. I think the NAM and GFS might be squeezing out too much precipitation further south, which is cutting things off to the north. You can even see the QPF streaming from the Pacific Ocean, indicating this system will have at least two sources of moisture (a southeasterly flow would also bring in moisture from the Atlantic Ocean if things lined up right).

I just don't buy into the widespread +2 amounts the GFS is showing - it's covering an area nearly 3 times the size of TX... I guess we should be looking for some major flooding along the MS river, LOL

Aight... 12Z GGEM is now in, and it's further north than the NAM at the SFC. After closely reviewing the 12Z RGEM, it too is further north than the NAM. The GFS is definitely the odd-man-out on this one. If that further north track verifies, my area would be looking forward to a significant ZR event.

EDIT:

12Z UKMET same strength as the NAM, but a touch further north... Looks like the GFS is the farthest south, with the NAM coming in second. The GEM, UKMET, and FSL RUC are all similar, with the FSL RUC being the farthest north. I'm going to say a split between the NAM/GEM/UKMET is the way to go.
 
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Wow

Huge changes to the forecast as a much farther northwest track is now pretty much model concensus and is evident watching the storm track. Available moisture and dynamics are very good, and snow ratios are high. This means a good shift of accumulating snow farther north and west into the plains then expected, and the National Weather Service has heralded these changes with new advisories and watches farther north and west.

Latest model runs now show decent moderate accumulating snows in NE Nebraska and southeast South Dakota, areas not covered previously by any sort of advisories or watches. In fact, snow totals in NE Nebraska to SC Minnesota will be very close to Winter Storm Warning criteria. The NWS in Omaha nearly jumped the gun with winter storm warnings but decided against it...for now, but are closely monitoring. Will personally call a 5-7" likelyhood in these areas, as some banding will likely locally increase snowfall amounts in these areas. I suspect some upgrades to winter storm warnings will occur by the midday package once the situation becomes clearer still.

WRF-NRM and NGM models clearly consistent with the moderate precipitation in the comma portion of this system in these areas, as is GFS, albeit GFS continues a somewhat weaker QPF overall. Persons in Eastern Iowa will really have to watch it as a combination of a bullseye of highest QPF and some freezing precipitation may cause icing and moderate snow accumulations. (Davenport, IA/Quad Cities, Coralville, Utica, IL)

Farther east, following WRF model guidance, would suspect heavy snows in a Lansing to Flint area, with the rain-snow line probably right around the Detroit area, and pushed north some from last guidance...but those areas might have snow accumulations hampered by a sleet-snow mix as well.

Farther south areas in Ohio will see just rain out of this...think NW Ohio and extreme SE Michigan has been cleared of the threat of snow but now looks like a lot of ice is marginally possible in areas like Toledo, Defiance, Monroe, Hillsdale. I believe the temperature however (based on years of living there) will be just a tad above freezing and it will be a marginal situation. NWS correctly issued a WSWATCH due to the potential in these areas.

Summary: Farther northwest track and plenty of moisture means a significant increase in snow and blowing snow in the plains east to the southern great lakes. Targeted cities to watch for the snow: Sioux City, Minneapolis, Milwaukee, Lansing, Flint.

FIRST CALL SNOWFALL FORECASTS (Personal). These forecasts are solely my opinion and do not reflect official forecast reasoning and are not official products. Use at your own risk.

Sioux City: 5.5"
Minneapolis: 7.0"
Milwaukee: 6.5"
Davenport: 7.5"
Lansing: 5.0" (sleet tempering)
Flint: 4.5" (sleet tempering)
Detroit: 2.0" (wintery mix tempering)
Toledo: 0.4", 0.1" to 0.2" ice
 
Looks like the northern track is going to win... Wouldn't be surprised to see it end up a bit further north than the 06Z NAM. I must say, the NAM did a good job at depicting the ongoing ZR event over southern MI right now. It's hard to guage rainfall/QPF amounts with all of this brightbanding going on. Wouldn't be surprised to see some areas pickup 0.15 to 0.25 inches of ice (isolated higher amounts) over southern MI with this first batch, then a second dose of even heavier precipitation tonight through Monday morning.

Looks like my area (just north of Detroit) is setup nicely for a significant ZR event over the next 24-30 hours.
 
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