December Med/Long Range Discussion

[showmethesnow]

500's aren't great looking but they were a slight improvement over the 06Z. Helps to keep the heights in the east down a touch more.

[psuhoffman]

I think we lost the ggem. Only snow map is updated and only to 6z sat but I can see where the snow is increasing the last 12 hours and it's in a bad spot. Up near Chicago and north. No increase in the places we would want or where it was last run like southern Ohio and northern ky into WV and western VA. This run nothing there. Snow pattern looks cutter ish to me. 

[psuhoffman]

Matt might have to warm up his "next" for this one. 

[BTRWx]

2 hours ago, MillvilleWx said:

After forecasting at my job for going on 2 years, I've noticed the Euro and GFS are certainly on a more level playing field than in years past. It used to be Euro (The King) in all aspects of numerical output, especially at long leads. The upgrades over the years to the GFS have made it on a more level playing field compared to other guidance. In terms of the 500mb pattern, the Euro still gets my nod as slightly better in terms of verification once we get inside 48-72 hours, but it's not by an egregious margin. 

There is one spot that the Euro does do better in than the GFS and that's tropical. As someone who forecasts out in the Caribbean, the surface reflection aspect of modeling in terms of QPF output and surface pressure analysis and handling of smaller mesoscale features, Euro has everyone by the throat. This is to my knowledge and experience. Could verification say otherwise, sure!! But I'll gladly use Euro for my forecasts in the Caribbean over many other pieces of guidance. Been doing a masterful job. 

I like the output from the para's recent last few runs.  The fact that it added a system when the op gfs had nothing for next weekend yesterday is encouraging to me.

[psuhoffman]

Ggem previp still not out but slp is to 138. Low is up near KS NE border when it was in Texas at same time 0z. It's better then the gfs for sure but pretty easy to see what way it's going. 

ETA: low cuts up over Detroit. Weaker then gfs and looks like more CAD initially but my take away is huge move towards gfs and away from keeping the system under us. Surface still not out so hard to tell how much frozen befire the flip but a bad run after what it had last night. 

EETA: the flip time looks about 18z on ggem. Hard to tell how much qpf before then until the surface comes out. 

[stormtracker]

1 minute ago, psuhoffman said:

Ggem previp still not out but slp is to 138. Low is up near KS NE border when it was in Texas at same time 0z. It's better then the gfs for sure but pretty easy to see what way it's going. 

Now watch the Euro come in with a 10" snow dump, followed by a prolific ice storm with drizzle at the end. 

Regardless, it'll flip back by 0z and we'll be ready to call it by 0z Tuesday.  

[psuhoffman]

2 minutes ago, stormtracker said:

Now watch the Euro come in with a 10" snow dump, followed by a prolific ice storm with drizzle at the end. 

Regardless, it'll flip back by 0z and we'll be ready to call it by 0z Tuesday.  

Wouldn't shock me. Even when things looked better there were plenty of bad runs within the ensembles. The full suite isn't in and judging by just two ops from this range is foolish. But the trends aren't good right now. They could turn around by next weekend for sure but all we can do is read the tea leaves we have right now 

[WinterWxLuvr]

3 minutes ago, losetoa6 said:

Ukie much weaker and further south then gfs at 144. Curious to see big brother euro later.  But this is  intriguing.

Best (only) good sign today.

[Thanatos_I_Am]

LWX recognized the threat

[Bob Chill]

Glad I went to bed before the euro and slept in. Lol

Ugly details well covered already. Only thing I will add is were getting close to the point where general track will be honed in on. Differences in timing/pecip onset are good clues to track now. It's pretty much unanimous that we lose the midlevels sometime around 12z Sat so our snow window is pretty much refined to overnight Friday.  0z EPS mean precip is decent during this time. .25+ on the means. Gefs isn't much different. 

Ice threat is looking more marginal outside of the usually suspects. I'm not expecting much there in my yard but that could easily change once temps become more clear. 

Theres still a disconnect with upper/mid levels vs surface late in the ens runs. EPS mean temps are still low to mid 40's for highs around there area for Christmas and the day after. Eps is acually cooler d15 than d14. Otoh- height patterns being advertised almost always = decent AN temps so we'll see 

[BTRWx]

17 minutes ago, Bob Chill said:

Glad I went to bed before the euro and slept in. Lol

Ugly details well covered already. Only thing I will add is were getting close to the point where general track will be honed in on. Differences in timing/pecip onset are good clues to track now. It's pretty much unanimous that we lose the midlevels sometime around 12z Sat so our snow window is pretty much refined to overnight Friday.  0z EPS mean precip is decent during this time. .25+ on the means. Gefs isn't much different. 

Ice threat is looking more marginal outside of the usually suspects. I'm not expecting much there in my yard but that could easily change once temps become more clear. 

Theres still a disconnect with upper/mid levels vs surface late in the ens runs. EPS mean temps are still low to mid 40's for highs around there area for Christmas and the day after. Eps is acually cooler d15 than d14. Otoh- height patterns being advertised almost always = decent AN temps so we'll see 

The pattern is too volatile right now for that range.  The only thing we can really monitor at that range is trends in the heights imo.

[Deck Pic]

Meh. There's not enough thump on the front end. Though the light stuff can obviously cause ice issues. 

[Bob Chill]

5 minutes ago, Deck Pic said:

Meh. There's not enough thump on the front end. Though the light stuff can obviously cause ice issues. 

Yea, crappy run. Nw shift with everything again. 

[CAPE]

6 minutes ago, Deck Pic said:

Meh. There's not enough thump on the front end. Though the light stuff can obviously cause ice issues. 

Yeah weak. A coating of snow, a few sleet pellets and some freezing drizzle.

[Deck Pic]

1 minute ago, Bob Chill said:

Yea, crappy run. Nw shift with everything again. 

We kind of suck at December. 

[stormtracker]

GFS is the new EURO

[WxUSAF]

10 minutes ago, stormtracker said:

GFS is the new EURO

I'm sure the GFS will waffle at some point so DT can claim another crushing victory for the king. 

[Bob Chill]

At least the euro has a d9 threat. Mid levels dicey but nice hit from 95 nw. 

[stormtracker]

7 minutes ago, Bob Chill said:

At least the euro has a d9 threat. Mid levels dicey but nice hit from 95 nw. 

Only 10 days away!

[87storms]

4 minutes ago, Bob Chill said:

At least the euro has a d9 threat. Mid levels dicey but nice hit from 95 nw. 

Not that I'm being very scientific here but from my experience around these parts is that we usually need a pattern to establish itself before we get our storms.  Jan/Feb...outside of that is always difficult here.

[CAPE]

4 minutes ago, Bob Chill said:

At least the euro has a d9 threat. Mid levels dicey but nice hit from 95 nw. 

Chasing unicorns lol. Nice to see something I guess, but man there is not much to like about the advertised h5 pattern this run. 

[mdsnowlover]

13 minutes ago, Bob Chill said:

At least the euro has a d9 threat. Mid levels dicey but nice hit from 95 nw. 

at least it's coming from the south, good  sign, and exits to our south

[Bob Chill]

8 minutes ago, C.A.P.E. said:

Chasing unicorns lol. Nice to see something I guess, but man there is not much to like about the advertised h5 pattern this run. 

It's a phantom for sure but hey, after the potential fail next weekend there's another cold air mass in place so there's a potential window. That's about it.  

Even though the trends have been bad for next weekend it's not like we're inside of 4 days and losing ground when it usually means slim chances for improvement 

[WinterWxLuvr]

Glad to see others mirroring my thoughts that the Euro has just delivered its next nut crushing solution.

[mdsnowlover]

4 minutes ago, Bob Chill said:

It's a phantom for sure but hey, after the potential fail next weekend there's another cold air mass in place so there's a potential window. That's about it.  

Even though the trends have been bad for next weekend it's not like we're inside of 4 days and losing ground when it usually means slim chances for improvement 

always enjoy reading your analysis, very informative tyvm, seems like the storm on 21 st changes the storm track in a favorable way for us

[nflwxman]

15 minutes ago, Bob Chill said:

It's a phantom for sure but hey, after the potential fail next weekend there's another cold air mass in place so there's a potential window. That's about it.  

Even though the trends have been bad for next weekend it's not like we're inside of 4 days and losing ground when it usually means slim chances for improvement 

 

It's absolutely undeniable that the trends and the modeled upper level pattern support a hard cutter next weekend, but the fact we are looking at next weekend in horror already is premature.  There have been multiple occasions, within 120 hours (which we are certainly not), where both ENS and operational have seen wholesale changes.  2 Decembers ago, the Euro and EPS had a monster low 105 hours out dumping 6-12" on the area, while the GFS stayed suppressed.  Ultimately the GFS won out with a complete non-storm that gave some light tropical showers to northern florida.  As we know, the GFS has seen those changes within 100 hours before.  At this range, we can have high confidence there where a low somewhere over the middle of the country at this range and that's about it.

 

IMO, here is what needs to change to give a chance for significant winter impacts from whats currently modeled:

 

* Wedge is underestimated at the surface (high pressure lingers over the NE longer) and provides extended icing:  LIKELY

* Primary Low is much weaker cutting through the lakes.  Low over northern texas stays strong: SOMEWHAT UNLIKELY

* Precip shield is more expansive and moves quicker than currently modeled: SOMEWHAT LIKELY WE SEE THIS OFTEN

* High Pressure magically saves us by moving quickly into the Minnesota and blocks any cutting and moves more towards a southern slider solution: VERY UNLIKELY GIVEN THE +AO

[Round Hill WX]

41 minutes ago, nflwxman said:

 

It's absolutely undeniable that the trends and the modeled upper level pattern support a hard cutter next weekend, but the fact we are looking at next weekend in horror already is premature.  There have been multiple occasions, within 120 hours (which we are certainly not), where both ENS and operational have seen wholesale changes.  2 Decembers ago, the Euro and EPS had a monster low 105 hours out dumping 6-12" on the area, while the GFS stayed suppressed.  Ultimately the GFS won out with a complete non-storm that gave some light tropical showers to northern florida.  As we know, the GFS has seen those changes within 100 hours before.  At this range, we can have high confidence there where a low somewhere over the middle of the country at this range and that's about it.

 

IMO, here is what needs to change to give a chance for significant winter impacts from whats currently modeled:

 

* Wedge is underestimated at the surface (high pressure lingers over the NE longer) and provides extended icing:  LIKELY

* Primary Low is much weaker cutting through the lakes.  Low over northern texas stays strong: SOMEWHAT UNLIKELY

* Precip shield is more expansive and moves quicker than currently modeled: SOMEWHAT LIKELY WE SEE THIS OFTEN

* High Pressure magically saves us by moving quickly into the Minnesota and blocks any cutting and moves more towards a southern slider solution: VERY UNLIKELY GIVEN THE +AO

I agree with all of this. However, the lack of NA blocking renders anything but a deep cutter unlikely. 

Now, the further west the low(Wisco)....the more likely ANY high to our north can hold in CAD. Southerlies would be weaker for our region with the further west the low which may mean more onset frozen. High location will be dependent. Unfortunately that high will be rocketing NE w/o NA blocking to hold it in. 

[Windman18]

12z Para GFS looked pretty sweet. Snow to rain back to heavy snow. Gives the area 8-12" it looks like.

[BristowWx]

I saw the para as well. It looked sweet with snow to sleet on Xmas eve too.  It's a model like the others so who knows.  

[Ji]

5 minutes ago, Windman18 said:

12z Para GFS looked pretty sweet. Snow to rain back to heavy snow. Gives the area 8-12" it looks like.

Best gfs run since hecs of Jan 2016