10/29-10/31 Halloween Winter Storm

[Stormhunter87]

Southeast shift with 00z GFS (least over Nebraska)

Yeah definitely looking south east. Good banding but not as solid as the 18z

[NH4NU]

Some signs of enhancement at 102hrs

[jcwxguy]

00z gfs

[jcwxguy]

Closer look

[clintbeed1993]

I refuse to believe I get missed to the South by snow in OCTOBER This will end up a bit further Northwest by the time it's all said and done

[bud2380]

Canadian very weak this run.

[jcwxguy]

Cmc weak sauce

[Minny_Weather]

Lezak made a good point. We won't get a better understanding on the low until it actually exists. Anything regarding track, strength, etc. should be taken with a grain of salt till at least Monday.

[jcwxguy]

Ukmet se and little weaker as well. Hard to tell how much is snow for iowa

[bud2380]

Euro with a 1006mb SLP in Ohio by hour 120. Can’t see precious yet but I’m guessing. It’s weaker overall and further southeast with precip

[bud2380]

Euro still showing a band of .25-.4” qpf with wave one Monday night over eastern Iowa.

[bud2380]

Euro much weaker with wave 2. Drops maybe a quarter inch or so of qpf as snow in eastern Iowa. On the plus side I’m in the heavier band. Overall a disappointing downward trend from the Euro. But we’re still talking 4+ days away

[Hawkeye]

Holy cow, the euro looks like the Canadian.... very weak.  Instead of the energy going negative tilt and wrapping up, it remains more positively tilted and just kinda gets dragged through the midwest.  That's a major change.

[Grizzcoat]

DMX with one of their better AFD's --

 

/Wednesday through Saturday/...

Confidence: Low to Medium Due to Wide Model Variations/Storm
Evolution and Changing Solutions

Varying signals remain regarding the storm for Wednesday through
Thursday night. A day or two ago and still yet with the GFS
tonight...a more amplified upper level H500 low was forecast to
track over Iowa with a band of moderate or higher snowfall. However,
after having a similar signal a day or two ago, the Euro has backed
off considerably with the main H850 moisture channel/sfc low far
enough east of the region with a concurrent weaker H500 low tracking
over the region. P-type is generally not a question as temperatures/
thickness point to mostly all snow or perhaps an intermittent mix at
times. The challenge that remains is regarding the models` handling
of the system in general. All trends so far point to the GFS chasing
the changes of the Euro the past 3 to 4 days. Today the Euro is a
weaker, less phased solution between the trailing H500 low and the
leading H850/sfc low and moisture channel. A shifting of solutions
from strong to weaker, and then many times back to stronger solution
within 2 to 3 days of the storm`s arrival is quite common with a
system when dealing with the southern and northern stream phasing
vs. not phasing. Often the solution is quickly reversed once the
system closer or is over the Rockies. The point of decision for this
storm when that occurs will be Monday night/early Tuesday when the
trailing jet begins digging south/southeast in the Northern Rockies.
Currently the models begin to swing the upper level H500 trough more
east as the jet rounds the bottom of the trough more quickly.
Previously, the jet was digging south a bit longer before making the
turn east; resulting in a deeper north south trough evolution and
stronger amplification of the entire system. This large uncertainty
is driving the low to medium confidence for the mid to late week
system. It`s pointless at this time to even entertain detailed
forcing and dynamics that may/may not bring a certain amount of
snowfall to a given area. With the current set of solutions, the
Euro model would project as little as a several of inches of snow.
Conversely, the slightly lagging (compared to the now weaker Euro)
GFS solution still holding on to a stronger solution yields headline
snow amounts above 6 inches on the 00z run. Neither is correct at
this time.

 

LONG TERM...REV

[GDR]

Wow so the icon is out in lala land and the Canadian and king are weak turds!

[Grizzcoat]

06Z GFS holds serve. Good hit for many reading this. Even a shift E. If only it was Wed.....

 

[GDR]

[Tom]

00z GEFS not budging nor enthusiastic of any NW trend in this pattern...still lots of time to see this unfold but my gut says we are generally seeing where this storm will dump snows across the Plains of NE/KS into IA/WI...maybe into N MO/N IL???  We'll have to see how quickly this storm deepens as it cuts NE up the OHV.  These details will be ironed out in the days to come esp when having to track early season snows and models tend to over due warmth at the higher levels of the atmosphere.

 

[Tom]

Both the 00z GEFS/EPS trends are for more upstream blocking across SE Canada...

 

 

[OKwx2k4]

00z GEFS not budging nor enthusiastic of any NW trend in this pattern...still lots of time to see this unfold but my gut says we are generally seeing where this storm will dump snows across the Plains of NE/KS into IA/WI...maybe into N MO/N IL??? We'll have to see how quickly this storm deepens as it cuts NE up the OHV. These details will be ironed out in the days to come esp when having to track early season snows and models tend to over due warmth at the higher levels of the atmosphere.

 

Theres also still time for that thing to swing further se and deepen also. Wouldn't that trip all the NW trenders out. Lol.

 

I say this because the blend of GFS ensembles that are being posted all seem to average further south and east than oppo GFS.

[Tom]

Theres also still time for that thing to swing further se and deepen also. Wouldn't that trip all the NW trenders out. Lol.

 

I say this because the blend of GFS ensembles that are being posted all seem to average further south and east than oppo GFS.

06z GEFS even a touch farther SE...N MO does well...

 

[Grizzcoat]

Interesting take from Kansas City WFO-  (the NBM blend must not include the GEFS? which makes no sense)-

 

The large upper level low pressure over central Canada will send
another shortwave south into the western Rockies Wednesday, which
will start to cut off as it enters the Southern Plains. This will
develop a favorable synoptic set up for large scale accent over our
area Wednesday afternoon. Guidance is overall similar on the
synoptic scale set up, but the GFS has a deeper, more negatively
tilted upper level low than the ECMWF. This creates more upper level
diffluence and lift increasing the mid level frontogenesis. This is
likely why the GFS has more QPF and overall snow totals the the
ECMWF and Canadian models. Our National Blend of Models (NBM), which
utilizes deterministic and ensemble members, made a rather drastic
decrease in QPF over northern Missouri into Iowa with the 00z run.
This trend will be worth watching as it take into account many
different solution as opposed to the deterministic ones we tend to
see the most. Due to the drastic drop in QPF we decided as a region
to blend some of the WPC QPF into the forecast to keep from flip
flopping from previous NBM runs. This approach still has most of the
area getting at least an inch of snowfall Wed-Thur with 2+" over
northern Missouri. One feature to watch is the dry slot that forms
with this system Thursday morning. This may cause a loss of ice
crystals over the KC Metro leading to more of a freezing drizzle
scenario along the I-70 corridor. GFS soundings do indicate this is
possible so it will need to be monitored as the event gets closer.
The cooler airmass and below normal temperatures look to stick
around into the next weekend as high pressure builds into the
Plains.

[Tom]

IMHO, I still see this system rapidly intensifying as it tracks up towards the OHV/GL's as this has been the trend and where this seasons Long Term, Long Wave Trough has been establishing itself.  Not to mention, but the LR tool I used to predict this storm system well over a couple weeks ago had a rapidly intensifying storm across the Aleutians in mid October.  The pattern is ripe for this storm to "bomb" out, esp if the upstream blocking becomes more and more sufficient.  I could see the Euro trend back towards those stronger solutions it was showing in earlier runs.  We may be seeing typical medium range model chaos.

[Clinton]

IMHO, I still see this system rapidly intensifying as it tracks up towards the OHV/GL's as this has been the trend and where this seasons Long Term, Long Wave Trough has been establishing itself.  Not to mention, but the LR tool I used to predict this storm system well over a couple weeks ago had a rapidly intensifying storm across the Aleutians in mid October.  The pattern is ripe for this storm to "bomb" out, esp if the upstream blocking becomes more and more sufficient.  I could see the Euro trend back towards those stronger solutions it was showing in earlier runs.  We may be seeing typical medium range model chaos.

I agree I think it may be Tuesday before we lock in on strength and track, given thats when the energy will actually for a storm.

[Clinton]

Both the 00z GEFS/EPS trends are for more upstream blocking across SE Canada...

Should help the storm dig and strengthen right?

[Tom]

Should help the storm dig and strengthen right?

Yup, this has been part of the new LRC that has seen ridging in eastern Canada. This allows for a favorable storm track that creates a “cutter alley” over our Sub.

[GDR]

I think the exact storm track will be known around Wednesday when tom gets out his magnet and pulls it into Chicago!

[jaster220]

These type of winds are no bueno for GL's shorelines........

 

  Unfortunately, that looks to be pretty likely scenario (again) and may again be the biggest story for the Mitt with this shoulder-season storm. 

[jaster220]

06z GEFS even a touch farther SE...N MO does well...

 

 

Warmth shadow of the GLs around the Mitt. Can it get any more obvious than this map, lol

 

IMHO, I still see this system rapidly intensifying as it tracks up towards the OHV/GL's as this has been the trend and where this seasons Long Term, Long Wave Trough has been establishing itself.  Not to mention, but the LR tool I used to predict this storm system well over a couple weeks ago had a rapidly intensifying storm across the Aleutians in mid October.  The pattern is ripe for this storm to "bomb" out, esp if the upstream blocking becomes more and more sufficient.  I could see the Euro trend back towards those stronger solutions it was showing in earlier runs.  We may be seeing typical medium range model chaos.

 

I think those on the west end of the sub are experiencing the frustrations of a Long Wave Trough that may well be trumping typical climo attm. I remember last Feb when storms would start out on models looking pretty favorable over this way, just to slowly slip away to the NW due to the predominance of the SER and a western trough. Trust me, I know the feeling and it ain't a nice one, lol

 

On the second bolded I noted quite a while back the atmospheric trends of storms reaching max intensity and then, due to blocking rocking, getting stalled or looping etc. Looks to be a pretty big feature of the current pattern. Last night's storm was actually one of the more progressive movers during it's peak strength. It slowed but didn't stall nor loop. 

[Tom]

12z ICON bombs out the storm as it tracks up towards the GL's...from 1010mb down to 979mb in 24 hours...that's once sweet looking ULL feature.  We've been spoiled tracking several of these already this season.

 

 

[bud2380]

GFS coming in pretty strong tomorrow night in Eastern Iowa.  Looks a lot like the Euro. 

[bud2380]

I'm guessing a lot of melting will go on initially, but the fact that it's moving through overnight should help accums.  Still this time of year and such a quick hitter, I can't imagine more than 1-2".  But there are spots of > .5" qpf showing up on the GFS. 

[Tom]

12z GFS with a little more than just a "tease" before the main event for IA/WI posters...

 

[bud2380]

 GFS wave 1

 

[Grizzcoat]

12Z GFS misses most of NE-- further E trend continues along with less precip

[Minny_Weather]

I'm putting zero stock in that GFS. Models are still a crapshoot and I have a hard time believing a low will be that far East in late October.

 

I'll start believing it if models continue showing that come tomorrow night.

[Minny_Weather]

Since nobody posted any maps, here's last night's Euro. Repeating, this is LAST NIGHT'S 00Z run. Not current. Shows both the Tuesday wave and the main wave.

 

 

[Hawkeye]

12z GFS definitely a move toward the euro.  The GFS is just chasing the euro around.  I'd take this run, though, as it's all snow here.

[hlcater]

Makes perfect sense the second storm is further SE if the initial wave tomorrow is stronger than advertised.

[bud2380]

GFS is about as good as I could hope for here in the Iowa City/Cedar Rapids area.  Very similar to the Euro on both waves now.