October 2017 Observations and Discussion

[Tom]

As we approach one of the fastest cooling months of the season, will nature agree???  This month provides us with one of the more fascinating periods of weather as a brand new weather pattern emerges as the sun sets over the Pole in early October.

 

Based on what I'm seeing, there is a likely atmospheric La-Nina response and many storms/troughs are likely to target the West/PAC NW as we open up October.  Depending on how strong the eastern CONUS ridge sets up, parts of the Midwest/Lakes/OV will experience above normal temps to open up the month.  I'm not to confident folks in the Plains will be as warm as those farther east.  It'll all depend on how these systems track into the west coast.

 

00z GEFS are seeing an impressive Bearing Sea ridge Day 3-7 which almost always produces a big SE Ridge...this would extrapolate into the open week of October for the lower 48...

 

 

 

 

 

Dejavu ala 2016???  Let's see how this month transpires...

 

 

 

[Tom]

Since we have about a week left of September, I thought it would be a good idea to show some previous forecasts the CFSv2 was showing for the month of Sept and how the model did overall.  Below is a map showing the current temp anomalies for the entire CONUS...

 

 

 

This was the CFSv2's temp trends on Aug 31st...

 

 

http://www.cpc.ncep.noaa.gov/products/people/mchen/CFSv2FCST/monthly/images/summaryCFSv2.NaT2m.201709.gif

 

 

 

With about a week left in the month and forecasts suggesting more cool weather in the west (except the PAC NW) and warmth in the east...its safe to say the model did a good job with the cooler than normal forecast in the south/southeast

 

 

 

You could argue the torch across the West was a bit to much, but overall, the CFSv2 did do a good job with wild temp swings averaging out to a warmer west and cooler east.  

[Tom]

Big changes evolving in both the GFS/EURO around Day 7/8 which are the opening days of October.  Both models have flipped to a bigger SW/W coast ridge and in response carving out a bigger trough over the central CONUS which was not there over the last 2 days of runs.  What I think may be happening are the models responding to the warmer waters hugging the NW NAMER coastline.  Notice the 4 consecutive frames on the 12z Euro run and how a trough gets almost absorbed into the pocket of colder waters north of Hawaii which are located right where the trough goes.

 

 

I find this interesting because this is what we saw the models do back in the winters of 2013-14 & 2014-15.  Some known bias's are to place troughs where there should be ridges due to SST temps.  I'd like to see if this is a trend or just a "head fake" but my hunch is the trend will continue.  It would also fit the 500mb pattern the CFSv2 is trending towards for the month of October.

 

 

 

http://www.ospo.noaa.gov/data/sst/anomaly/2017/anomnight.9.21.2017.gif

[Tom]

As we open up the month of October, GEFS are signaling a wetter pattern across the Plains states.  For days, it has been showing a bone dry pattern.  Let's see if it holds as the new LRC develops.

 

[Tom]

00z EPS Week 2...however, some guidance suggests there may be systems cutting underneath blocking to the north which may cut into the warmth models are portraying...

 

 

[james1976]

00z EPS Week 2...however, some guidance suggests there may be systems cutting underneath blocking to the north which may cut into the warmth models are portraying...

 

 

Full on blow torch if that pans out.

[Tom]

Remember that trough I have been anticipating targeting British Columbia/PAC NW???  It's showing up as we open October and trends in the GEFS are showing it dig farther south into the Rockies.  Here is the 500mb trend forecast...notice the blocking across NW NAMER which was not there all but a couple days ago.  I really think the models are underplaying the above normal waters hugging NW NAMER.  Good trends.

 

 

 

[Tom]

00z Euro EPS..can you find the mean trough???  If this transpires, it would mean troughs have that look of digging farther south unlike October 2016.  Plains states will likely be closer to the active storm track and result in above normal precip and closer to normal temps.

 

 

 

[Tom]

For those in the Plains states, who remembers last year's long term long wave ridge that dominated the pattern???  A new year brings a new pattern and this one looks much more favorable for a SW Flow to open up October.  Remember last year the early record cold which targeted British Columbia/Alberta region???  Troughs favored targeting SW Canada and the coastline of the state of Washington/Oregon.  Storms did not really dig farther south into California early on in the season.  This year, something different seems to be aligning which is better news for storms to track farther south and into the central Rockies instead of the northern Rockies early on in October.

 

Here is a 500mb forecast for the first day of October and notice the ridge placement is farther east compared to last year which was in the middle of the nation.  We'll have to see where storms intensify and track as the new pattern evolves but I'm seeing encouraging signs that this new pattern will deliver more action this season across the states that were hung dry last Autumn.

 

 

 

[Minny_Weather]

Looks like we're locked in for a warm first half of October, which means we will likely not see a freeze until the second half of October, which is rare. That doesn't dictate how Winter will go, obviously. One of our best Winters in history had our first freeze fall in November. As we get past the second full week of October, it looks like we get into a more dynamic pattern, which is then I think the lower elevations of the high Plains and maybe CO will see their first snow chances, as long as our possible first freeze here. It is looking like both the EPS weeklies and most CFSv2 members are picking up on a nice trough out of AK mid-October.

[Tom]

Agree, 1st half looks toasty and wetter for those who missed out on the rains. I don't mind the warmer temps so long its active. As you stated, warmer October's don't necessarily dictate what happens in Winter, esp with a mid Niña incoming. I've been noticing that trough around middle of the Month showing up on the CFSv2 weeklies. Start warm and finish cold?

[Tom]

I hate to say this, but some places on here east of the Plains will be seeing more record heat Week 2.  Guidance is suggest a powerhouse ridge in the East to blossom.  However, there is some caution as to how much influence blocking across NW NAMER/NE PAC will have across the Plains/Midwest.  I'm seeing more blocking on the EPS/GEPS that was not there over the last 3 days of runs.  Nonetheless, it looks like a warmer regime with a possibility of near normal temps in the central Plains.

 

 

[Minny_Weather]

Agree, 1st half looks toasty and wetter for those who missed out on the rains. I don't mind the warmer temps so long its active. As you stated, warmer October's don't necessarily dictate what happens in Winter, esp with a mid Niña incoming. I've been noticing that trough around middle of the Month showing up on the CFSv2 weeklies. Start warm and finish cold?

I'm fine with the warmth 1) because of the more active pattern and 2) because we should still be far from any records here in NE. In October, many record highs are still in the 90s. Early October is usually the very last gasp for severe weather season here before it overall gets too stable. So I am hoping we can capitalize on that. 

[Tom]

I'm fine with the warmth 1) because of the more active pattern and 2) because we should still be far from any records here in NE. In October, many record highs are still in the 90s. Early October is usually the very last gasp for severe weather season here before it overall gets too stable. So I am hoping we can capitalize on that. 

 

I'm all for it and it would be a whole lot better start to the new cyclical pattern to see storms coming out of the central Rockies.  Even though we haven't seen our first Frost/Freezes yet, you could say Indian Summer conditions shall continue for the foreseeable future.

[jaster220]

I'm all for it and it would be a whole lot better start to the new cyclical pattern to see storms coming out of the central Rockies.  Even though we haven't seen our first Frost/Freezes yet, you could say Indian Summer conditions shall continue for the foreseeable future.

 

Fixed..

 

(gotta have 1st frozen morning to get Indian summer)

[jaster220]

Looks like we're locked in for a warm first half of October, which means we will likely not see a freeze until the second half of October, which is rare. That doesn't dictate how Winter will go, obviously. One of our best Winters in history had our first freeze fall in November. As we get past the second full week of October, it looks like we get into a more dynamic pattern, which is then I think the lower elevations of the high Plains and maybe CO will see their first snow chances, as long as our possible first freeze here. It is looking like both the EPS weeklies and most CFSv2 members are picking up on a nice trough out of AK mid-October.

 

Agree, 1st half looks toasty and wetter for those who missed out on the rains. I don't mind the warmer temps so long its active. As you stated, warmer October's don't necessarily dictate what happens in Winter, esp with a mid Niña incoming. I've been noticing that trough around middle of the Month showing up on the CFSv2 weeklies. Start warm and finish cold?

 

 I mentioned the 2-faced month of Oct 2013, and just found some proof:

 

 

[Tom]

Fixed..

 

(gotta have 1st frozen morning to get Indian summer)

That's why I stated..."could" say bc it really won't be an official Indian summer... ...so yes, Summer conditions..."to be continued:...

[Tom]

I already see the trends, models have been under-playing the blocking in the Week 2 range and today's 12z GFS continues that trend.  It's going to be a different year watching these models come in.  -QBO & the SST's in NE PAC are going to be players this cold season.

[james1976]

Yeah GFS looks kinda warm next week and then troughy after that.

[james1976]

Would be nice if that was the trend with the new LRC evolving.

[Tom]

Watch the trends in the Alaskan Ridge for the opening day of October where the new LRC is forming...none of the models saw this coming 4-5 days ago....

 

 

[james1976]

Watch the trends in the Alaskan Ridge for the opening day of October where the new LRC is forming...none of the models saw this coming 4-5 days ago....

Look at all that blocking!

[jaster220]

I already see the trends, models have been under-playing the blocking in the Week 2 range and today's 12z GFS continues that trend.  It's going to be a different year watching these models come in.  -QBO & the SST's in NE PAC are going to be players this cold season.

 

One can hope..

 

 

[Niko]

One can hope..

 

Nov thru Jan -QBO for analog yrs.jpg

Man, that blue color looks beautiful on us.

[gabel23]

18z GFS looks active and the Cubs clinch!! Doesn't get better than that! Fantasy land I know, but I would take that pattern as part of the new LRC! 

[Tom]

18z GFS looks active and the Cubs clinch!! Doesn't get better than that! Fantasy land I know, but I would take that pattern as part of the new LRC!

Real nice looking SW Flow and blocking! Didn't look like much a few days ago but now things are changing and looking good for an active storm track. You guys out there will prob not get as warm as us out here initially. Let's hope these trends stay consistent. Go Cubs Go!

[james1976]

Local met on news tonight said above normal first couple weeks of October. We shall see.

[OKwx2k4]

I mentioned the 2-faced month of Oct 2013, and just found some proof:

 

2013 Oct Temp Departs.jpg

This is more in line with what I'm thinking for this month. Hard flip somewhere in or at the start of the last 15 days of the month.

[OKwx2k4]

One can hope..

 

Nov thru Jan -QBO for analog yrs.jpg

-QBO combined with -ENSO, neutral to negative AO, and neutral dropping to negative PDO means that it will most likely shift that cold spot right to the central US and GL. This late fall and winter are looking better every day.

[Tom]

I like the active look the GFS is showing and fits the pattern evolving over in East Asia.  Cutter season is about to begin and like a flip of the switch, a strong signal for a solid SW Flow coming out of the Rockies should evolve. Shifting farther east slowly in time as GEFS are keeping the Plains states more cooler than those farther east.  I like this look early on in the Autumn season as a mean storm track evolves.

 

The state of NE looks to be the magnet where a storm track sets up in early October...

 

 

 

Cooler risks are showing up Week 2...

 

 

 

 

The new LRC is showing a wet start overall for many of us on here....

 

[Tom]

If both the Euro and GFS  are right, nature will slowly erode any drought conditions in the Plains/Upper Midwest...I think there is room for the Midwest to be included...

 

 

 

 

[Tom]

JMA weeklies showing a strong western trough Week 2 and a big ridge in the East.  Battle zone across the central CONUS.  Similar signal Week 3-4 with no real signal for warmth or cold and near average temps...but I do see a -NAO showing up.  The warmth that shows up early on in the month may disappear Week 2 as a back and forth pattern hits middle of the month.  

 

[jaster220]

-QBO combined with -ENSO, neutral to negative AO, and neutral dropping to negative PDO means that it will most likely shift that cold spot right to the central US and GL. This late fall and winter are looking better every day.

 

That shift west-ward you mention would be very much like BAMWx's first winter temps map that Tom posted over in that thread. I noticed in their webinar they had modified that a bit but it may turn out that their original idea was the more accurate one. 

 

 

 

The new LRC is showing a wet start overall for many of us on here....

 

Now that's more like it!  

[Niko]

 I mentioned the 2-faced month of Oct 2013, and just found some proof:

 

2013 Oct Temp Departs.jpg

That kinda looks like what will be happening this October. Warm start right up until mid month or so and then, a decline in temps.

[jaster220]

 

I like the active look the GFS is showing and fits the pattern evolving over in East Asia.  Cutter season is about to begin and like a flip of the switch, a strong signal for a solid SW Flow coming out of the Rockies should evolve. Shifting farther east slowly in time as GEFS are keeping the Plains states more cooler than those farther east.  I like this look early on in the Autumn season as a mean storm track evolves.

 

The state of NE looks to be the magnet where a storm track sets up in early October...

 

Speaking of active autumns, look at how often 2007 is showing up on this analog map! 

 

 

[Tom]

12z GFS hinting at a fire hose of moisture over next 10 days from the Plains up towards the Northwoods...

 

 

[jaster220]

^^^ with a FOOT of liquid, who needs snow maps? 

[Niko]

12z GFS hinting at a fire hose of moisture over next 10 days from the Plains up towards the Northwoods...

 

 

Looks good to me. I'll take it and run!

[Tom]

GEFS are trending way cooler post 10th and probably going to surprise a lot of folks.  NE PAC ridge is flexing its muscle around the 8th which is something I had a hunch would transpire given the SST's.  Still room for error but I think the trends are favoring more ridging across NW NAMER.

[Tom]

You can see the trends in the N PAC and focusing more attention in the NE PAC.  Over the last 4 days, it did not see the ridge...until today's 12z run...bigger implications for cooler weather in the central CONUS.