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Pattern December, Make analogs relevant again

accu35 said:
gfs_mslp_pcpn_frzn_us_46.png
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Aha! That still counts in the time frame that I'm thinking and I didn't say exactly where in the south, it could simply be a mid south storm.

But of course it's going to change multiple times still.
 
Snowflowxxl said:
Storm shows up for the SE around 312 again
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384 is even better, GFS really loves the Dec. 11-18th period for winter mischief. It'll be interesting to see if the storm signal for wintry weather gets stronger among weather models and holds true once we get to the middle of the month.
 
whamby said:
As Webber alluded to earlier, boy the GFS sure overdoes 'potential' snowcover radiational cooling..
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Is it really overdoing that much though? I don't know or remember what the snowcover on average was like across the US back in December 2010, but we easily saw quite a few morning lows in the teens after an arctic front passage.
 
Yes, the GFS is suggesting the southern stream is going to be active. I'm going to take one storm system at a time. I believe the first storm system will be between days 7-10 or so (Dec. 9th-12th) which a thread for that system maybe made soon.
 
Weatherlover92 said:
Is it really overdoing that much though? I don't know or remember what the snowcover on average was like across the US back in December 2010, but we easily saw quite a few morning lows in the teens after an arctic front passage.
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yeah, I don't know.. a good question for someone far more informed about weather models and current algorithms used.. it does seem to me just from a novice's observations of these models for a few years now, that it indeed is a thing.
 
whamby said:
yeah, I don't know.. a good question for someone far more informed about weather models and current algorithms used.. it does seem to me just from a novice's observations of these models for a few years now, that it indeed is a thing.
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GFS did this last year I believe. Showed snowcover around RAH and lows around 10-15 degrees BELOW zero! Only made it down to 5-10 above I believe. Larry should remember this! The "new" GFS upgrade may have fixed this, not sure!
 
oh the delicious memories, a video from the Jan 2011 snow in Chattanooga.. would love to see this kind of snow in December.. hasn't really happened in my lifetime since living here from 1989 on. The best Dec snow I've seen is the 2010 Christmas storm which was warmer than the Jan storm and only around 4 inches at my house. Of course, nothing comes close to March 93, when CHA had 2 feet of snow:
 
the neat thing about that jan 11 storm was how cold it was... we had heavy snow conditions and around 18 degrees for a time... amazing stuff. The Dec Christmas snow the temps were marginal, low 30s.
 
Takeaways from the tonight's Euro and Gfs: Gfs is a little stouter with the cold plunge, both have the two step arctic plunge out to 8 days. Euro and Gfs diverge after that...
ecmwf_T850_us_10.png
gfs_T850_us_37.png
 
MRX being cutesy and conservative as always:
Area Forecast Discussion
National Weather Service Morristown TN
335 AM EST Sat Dec 2 2017

.SHORT TERM...(Today and Tonight)...
A weak shortwave will cross the area today, bringing morning
clouds to the region. As the wave moves east this afternoon, skies
will clear. With very little moisture available, no precipitation
is anticipated today. Upper level flow becomes more amplified by
tonight, with ridging building out of the central US. This will
maintain dry and pleasant conditions areawide.

.LONG TERM...(Sunday through Friday)...
Amplified pattern results in ridging on Sunday and Monday keeping
us dry, mostly clear, and warm. In fact, we`ll have very warm
temperatures on Sunday and Monday with highs about 10 to 15
degrees above normal. High and midlevel clouds will be on the
increase during the day on Monday ahead of a longwave trough and
surface cold front. As a jet streak across the Upper Mississippi
River Valley and the Great Lakes strengthens on Monday, upper-
level divergence across the Ohio River Valley will lead to a
strengthening low-level jet across the Tennessee River Valley.
PoPs will increase on Monday night as isentropic lift increases.
The cold front will move through the region on Tuesday with likely
to categorical PoPs along and just ahead of the cold front
primarily midday Tuesday through early Tuesday night. There is not
much instability ahead of the cold front, so do not expect
thunderstorms at this time. Could also have some locally heavy
rainfall on Tuesday with PW values and integrated water vapor
transport around the 90th-95th percentile. There is much better
consistency in guidance and ensembles with the timing of the cold
front and heaviest precipitation, so forecast confidence is
increasing and is higher than yesterday with this upcoming system
on Tuesday.

We`ll have to pay for the amplified pattern and warm temperatures
early in the week with very cold air late week. Behind the cold
front, temperatures take a nosedive as troughing sets up over the
Eastern CONUS and cold, surface high pressure from Canada slides
southeastward into our region. Shortwave energy will continue to
rotate through the longwave troughing pattern keeping the late week
forecast cold and uncertain, and it will bring the potential for
some light rain or snow showers/flurries with these quick moving
systems. At this time, the best chance for precipitation may be on
Friday as models show a strong shortwave and quick moving surface
low with limited moisture moving through the Ohio River Valley, but
forecast confidence this far out is very low. Overall, the best
chance for precipitation late week will be across the higher
elevations where low-level winds will enhance orographic lift in
northwest flow and make the most efficient use of the limited
moisture. Just remember that the main weather story through late
next week is the very cold air. This will likely be the first real
shot of very cold air this winter season for our area with
temperatures potentially 10 or more degrees below normal on Thursday
and Friday.
 
in case you were trying to say the Gfs no longer has a snowcover radiational cooling bias, gander a sec at this one, lol:
gfs_T2m_us_53.png
 
whamby said:
MRX being cutesy and conservative as always:
Area Forecast Discussion
National Weather Service Morristown TN...We`ll have to pay for the amplified pattern and warm temperatures
early in the week with very cold air late week...
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I used to live in Chattanooga (what a fantastic city BTW) - MRX was so frustrating - extremely conservative - often just wrong esp with the microclimates of Chattanooga (Signal Mountain, Lookout, etc); now living in Greenville (SC), GSP seems much more focused/accurate
 
06z gfs shifted potential for sn / slt / fzra north, out of all of our reach. The 540 line only briefly drops into GA on those runs. Hope 12z looks better.

gfs_mslp_pcpn_frzn_us_13.png
 
tractor girl said:
06z gfs shifted potential for sn / slt / fzra north, out of all of our reach. The 540 line only briefly drops into GA on those runs. Hope 12z looks better.

gfs_mslp_pcpn_frzn_us_13.png
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I can count the times I've had a frontal passage end as snow, on one hand. Euro still has some potential in the Dec 10-15th period and cold still coming! Steady as she goes, good times ahead!
 
tractor girl said:
06z gfs shifted potential for sn / slt / fzra north, out of all of our reach. The 540 line only briefly drops into GA on those runs. Hope 12z looks better.

gfs_mslp_pcpn_frzn_us_13.png
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6z has seemed way warmer than the other 3 runs in the day for probably the same reason or similar to the one we saw with tropical cyclone intensity months ago. If that's the case, the systems aren't as strong, hence the warmer appearance.
 
gfs_mslp_pcpn_frzn_us_25.png
couple very close calls on the 6z this morning. Still a fairly cold run.
 
Huntsville NWS now put mentioning snow chance thur night and friday. Very unusual this for out for them to mention snow in the forecast.
Also, from their discussion:
At this point, would likely only
be a very light dusting and should not create any travel issues, but
we will need to monitor this system in case more moisture is able to
be drawn up ahead of it. Regardless, even colder air will likely push
into the area this weekend
 
Notes about the 06z GFS:
The late bloomer does bloom earlier than the 0z run and much closer to the eastern seaboard. Folks in eastern NC may score some back side SN/IP with that late bloomer. The late bloomer develops along the frontal boundary from the cutter system. If the timing is right, and if the bloomer system comes any closer to the eastern coast, northern GA/ Upstate SC and into NC (possibly eastern AL, eastern TN as well) and on points northeastward may score some back edge SN/IP. Still watching for that positive tilt trough diving into Mexico days 5-6 (Dec. 7th-8th) that could develop into a LP over the GOM.
 
dsaur said:
This right here is what has me interested. Love some suppression a week out, with the cold air working in. I think I could see some sleet from this, if it's still there, and it's been there from a few runs. T
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Yeah, seems that it been getting closet each run. I can see this actually coming closer to and at least providing sleet. Cold air is in place. I love a good sleet storm any day.
 
navgem_mslp_pcpn_us_23.png
this morning 6z NAVGEM has some energy behide the main band. Lol!!! Im bored, can't ja tell
 
accu35 said:
navgem_mslp_pcpn_us_23.png
this morning 6z NAVGEM has some energy behide the main band. Lol!!! Im bored, can't ja tell
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Go Christmas shopping. Come back to a great Euro and GFS run. Things are looking great!
 
Is there any site that shows EPS members like College of DuPage's site shows GEFS members?


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