December and January Pattern Discussion

[John1122]

It made me a bit sad, simply because it keeps pushing the systems to just past 180. It's the eternal day 8-10 storm that never gets any closer.

[Stovepipe]

It sure looks to be cold next week which should help ensure wintry precip.  The GFS lows Tuesday and Wednesday morning here are at or below 10 degrees with a high of 25 on Wednesday.  If TN is the battle zone for 850 temps, we could have some ice on our hands along with the snow.  Looks fun.

[Stovepipe]

It made me a bit sad, simply because it keeps pushing the systems to just past 180. It's the eternal day 8-10 storm that never gets any closer.

 

I'll feel better when we see this inside of the GFS truncation period.  Hopefully the Euro holds serve.

[John1122]

In the meanwhile we have 3 clippers coming through over the next 5 days. Flizzards inbound. 

[Stovepipe]

Congrats Mexico, the crazy uncle gives you 6 inches 13 inches of snow lol.

 

[ben4vols]

For anyone interested, of the 51 Euro ensembles on 0z for Nashville by hour 240:

 

43 show a dusting or more

16 show 1 inch or more

12 show 2 inches or more

6 show 4 inches or more

4 show 6 inches or more

1 shows 10 inches or more

 

Thanks Stove.

[Stovepipe]

12z Euro very cold and very dry.  It fiddled around but couldn't get anything going from the gulf until about hour 222 then as it moves into our area temps are marginal.  Still some snow but it sucks to see it delayed again.

 

Edit:  Looks like 2 to 4 inches for eastern third of TN and parts of western NC.

[tnweathernut]

I still think that time period is going to be a period to produce something Stove.  If the cold air isn't SO overwhelming.......... I can picture a low developing underneath it and cruising across while tapping the cold

[Stovepipe]

I still think that time period is going to be a period to produce something Stove.  If the cold air isn't SO overwhelming.......... I can picture a low developing underneath it and cruising across while tapping the cold

 

Oh I have above average enthusiasm about next week, especially if the ensembles continue to show good possibilities.  I just hate to see the Euro latch on to something good for 3 or 4 runs in a row and then drop it or push it back once it's under 200 hours. 

[Mr Bob]

I would not get excited yet either way...it was about this time frame both models dumped the super cold next Tuesday idea for temps in the 50s and now we spend the entire day under the -20C 850 isotherm. Still a few days from clarity.

[nrgjeff]

12Z suite, both GFS and Euro, seem strange late next week Thu/Fri. Could be a split flow with split systems in the Ohio Valley and Deep South. That's a forecast I won't touch 8-9 days out. However I will share this graphic of the Euro Day 10. AK ridge tries to rebuild. Note the above normal heights over the Canadian Maritimes. That reminds me of winter 2010-11 somewhat. Greenland is still different. Anyway the 500 mb flow is straight west to east from Texas to the Deep South with below normal heights through the Mid South. Though it is still Day 10 that's what I'm looking for!

[Stovepipe]

Larry just posted this in the SE forum:

 

 

Hot off of the press, the 12Z Euro ensemble mean for the 72 hours ending 12Z on 2/1 has even more snowfall than today's 0Z run, which itself was snowier than the already impressive run from 12Z yesterday that gave 1-2" for many here! So, the snowier trend continues. Actually, qpf isn't higher than the 0Z, but it is colder thus leading to a higher % of the precip. as snow.

 

 Since pictures are worth a thousand words, I'll just post the Earthsat maps to show the increase:

 

12Z 1/22 Euro ensemble mean 1"+ snowfall 72 hours ending 12Z on 2/1:

 

 

0Z 1/22 Euro ensemble mean 1"+ snowfall 72 hours ending 12Z on 2/1:

[tnweathernut]

Certainly looks like a strong signal to me.  Two observations:

 

1.  I am guessing many of the individuals are not as ambitious with the cold and therefore provides room for energy to develop         underneath it. 

 

2.  Looks like a Miller A ensemble mean if there ever was one.

 

Good stuff, thanks for sharing and thanks to Larry for posting.

[jaxjagman]

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED JANUARY 22 2014

6-10 DAY OUTLOOK FOR JAN 28 - FEB 01, 2014

THE MODELS ARE IN VERY GOOD AGREEMENT ON THE UPPER-LEVEL (500-HPA) CIRCULATION
PATTERN DURING THE 6-10 DAY PERIOD.  ALL OF THE AVAILABLE MODEL SOLUTIONS
DEPICT ABOVE-NORMAL 500-HPA HEIGHTS ACROSS ALASKA AND MOST OF THE WESTERN
CONUS, WITH BELOW-NORMAL HEIGHTS FROM THE GREAT PLAINS TO THE EAST COAST.  A
NOTABLE DIFFERENCE BETWEEN THE DETERMINISTIC MODELS AND THE ENSEMBLE MEANS IS
THE REPRESENTATION OF A SMALL AREA OF BELOW-NORMAL HEIGHTS OVER THE EASTERN
PACIFIC, WHICH IS MUCH MORE PRONOUNCED IN THE DETERMINISTIC RUNS.  TO ACCOUNT
FOR THE POSSIBILITY OF A STRONGER TROUGH NEAR THE PACIFIC NORTHWEST, THE MANUAL
BLEND IS ABOUT ONE-THIRD DETERMINISTIC MODELS (00Z GFS AND 00Z ECMWF), AND
TWO-THIRDS ENSEMBLE MEANS (06Z GFS ENSEMBLE AND 00Z ECMWF ENSEMBLE MEAN).  THE
TWO ENSEMBLE MEANS ARE CHOSEN AS THEY HAVE THE BEST BALANCE OF PAST PERFORMANCE
AND ANALOG CORRELATION SCORES.

THE 6-10 DAY TEMPERATURE OUTLOOK CALLS FOR ENHANCED ODDS OF BELOW-NORMAL
TEMPERATURES FROM NORTH DAKOTA TO LOUISIANA AND EASTWARD TO THE EAST COAST.
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHWEST, GREAT BASIN,
CALIFORNIA, PORTIONS OF THE NORTHERN ROCKIES, AND ALL OF ALASKA.  THE
UNCERTAINTY IN THE TROUGHING OVER THE EASTERN PACIFIC RESULTED IN THE LOW
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE NORTHERN ROCKIES AND
FAVORED NEAR-NORMAL TEMPERATURES FOR THE PACIFIC NORTHWEST. TEMPERATURES ACROSS
ALASKA ARE MOST LIKELY TO BE ABOVE-NORMAL WITH A STRONG RIDGE OVER MOST OF THE
STATE.

THE STRONG RIDGE OVER THE WESTERN PORTIONS OF NORTH AMERICA SHOULD KEEP THE
STORM TRACK ACROSS THE NORTHERN TIER OF THE CONUS, ALTHOUGH THERE IS SOME
UNCERTAINTY ON HOW THE SHORT-WAVE TROUGH WILL AFFECT THE PACIFIC NORTHWEST.
ABOVE-MEDIAN PRECIPITATION IS FAVORED FROM THE NORTHERN AND CENTRAL HIGH PLAINS
TO THE GREAT LAKES. ELSEWHERE, BELOW-MEDIAN PRECIPITATION IS FAVORED ACROSS THE
CONUS. THE STORM TRACK SHOULD BE FOCUSED ACROSS CENTRAL ALASKA, FAVORING
ABOVE-MEDIAN PRECIPITATION ACROSS THE NORTHERN AND EASTERN PORTIONS OF THE
STATE.

TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 15 PERCENT OF TODAY'S OPERATIONAL 0Z
GFS CENTERED ON DAY 8...35 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON
DAY 8...15 PERCENT OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8...AND 35
PERCENT OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8.

MODEL OF THE DAY: 00Z ECMWF ENSEMBLE MEAN AND 06Z GFS ENSEMBLE MEAN (TIED)

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
VERY GOOD MODEL AGREEMENT, LIMITED MODEL SPREAD, AND GOOD AGREEMENT AMONG THE
FORECAST TOOLS, TEMPERED BY SLIGHT DISAGREEMENT ON THE PLACEMENT OF THE TROUGH
OVER THE GULF OF ALASKA.

8-14 DAY OUTLOOK FOR JAN 30 - FEB 05, 2014

THE FORECAST FOR THE UPPER-LEVEL CIRCULATION PATTERN DURING THE 8-14 DAY PERIOD
IS LESS CERTAIN THAN DURING THE 6-10 DAY PERIOD.  MOST OF THE AVAILABLE MODEL
SOLUTIONS DEPICT ABOVE-NORMAL 500-HPA HEIGHTS ACROSS ALASKA, BELOW-NORMAL
HEIGHTS ACROSS THE NORTH CENTRAL CONUS, AND ABOVE-NORMAL HEIGHTS ACROSS THE
SOUTHERN TIER OF THE CONUS.  THE 00Z ECMWF ENSEMBLE MEAN IS THE OUTLIER, WITH
BELOW-NORMAL HEIGHTS EXTENDING TO THE GULF COAST.  ADDITIONALLY, THAT MODEL HAS
ONE BROAD AREA OF BELOW-NORMAL HEIGHTS ACROSS THE NORTH CENTRAL CONUS WHILE THE
OTHER MODEL SOLUTIONS HAVE TWO DISTINCT AREAS OF STRONGLY NEGATIVE HEIGHT
ANOMALIES.

THE 8-14 DAY TEMPERATURE OUTLOOK INDICATES THAT ABOVE-NORMAL TEMPERATURES ARE
FAVORED FOR NORTHERN ALASKA AND MUCH OF THE ALEUTIANS DUE TO RIDGING AND
ANOMALOUS SOUTHWESTERLY COMPONENT TO THE MEAN FLOW. ABOVE-NORMAL TEMPERATURES
ARE FAVORED OVER THE GREAT BASIN, CALIFORNIA, THE SOUTHWEST, AND THE SOUTHERN
HIGH PLAINS OF TEXAS. A MIX OF NEAR-NORMAL AND BELOW-NORMAL ARE FAVORED ACROSS
THE PACIFIC NORTHWEST AND NORTHERN ROCKIES AS BELOW-NORMAL HEIGHTS THERE
INDICATE SOME LOW-PRESSURE SYSTEMS ARE LIKELY TO TRAVERSE THAT REGION.
BELOW-NORMAL TEMPERATURES ARE FAVORED FROM MONTANA TO IOWA TO THE SOUTHEAST AND
EASTWARD TO THE EAST COAST, WITH THE EXCEPTION OF THE FLORIDA PENINSULA DUE TO
A PERSISTENT TROUGH. THE HIGHEST LIKELIHOOD OF BELOW-NORMAL TEMPERATURES AND
THE COLDEST TEMPERATURES IS SLIGHTLY FURTHER NORTH IN WEEK-2 THAN DURING THE
6-10 DAY PERIOD.

THE STORM TRACK DURING WEEK-2 IS LIKELY TO BE ACROSS THE NORTHERN TIER OF THE
CONUS, FAVORING ABOVE-MEDIAN PRECIPITATION FROM THE PACIFIC NORTHWEST, ACROSS
THE NORTHERN AND CENTRAL ROCKIES TO THE GREAT LAKES. THE POTENTIAL FOR A COLD
FRONT TO STALL ACROSS THE TENNESSEE VALLEY YIELDS INCREASED ODDS FOR
ABOVE-MEDIAN PRECIPITATION.  A DISPLACED STORM TRACK FAVORS BELOW-MEDIAN
PRECIPITATION ACROSS MOST OF CALIFORNIA, THE SOUTHWEST, AND THE SOUTHERN HIGH
PLAINS.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 15 PERCENT OF TODAY'S
OPERATIONAL 6Z GFS CENTERED ON DAY 11...10 PERCENT OF TODAY'S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11...35 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED
ON DAY 11...AND 40 PERCENT OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY
11.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO GOOD AGREEMENT AMONG MODELS AND FORECAST TOOLS, OFFSET SLIGHTLY BY
UNCERTAINTY IN THE PRECIPITATION OUTLOOK FOR THE FRONT RANGE OF THE ROCKIES AND
TENNESSEE VALLEY.

FORECASTER: MATT ROSENCRANS

NOTES: 

[Stovepipe]

18z GFS really juices up for our region.  Hour 240:

 

 

Snow Clown:

 

If we can ever shake this cold/dry/clipper pattern, good things could be possible.

 

Edit:  Sorry, that probably belongs in banter.

[Stovepipe]

FWIW the 12z Euro ensemble members look very good for cities across TN in terms of precip.

In the case of Knoxville, all but two show measurable snow through 240. 21 of them are 2 inches or more with quite a few 4-8 inchers in there. The ensemble mean is nearly 3 inches.

For Nashville, all but 8 have measurable snow with 22 of them greater than 2 inches, and again quite a few big dogs. Ensemble mean of 2.5 inches.

What's interesting when comparing the two locations is, the ensembles show more light clipper love to Knoxville but slightly more substantial snow potential for Nashville towards the end of the period. The common theme though is, something pretty big might happen around Jan 30 - Feb 1 that affects a large chunk of our region.

[jaxjagman]

EPS is starting the storm on the 29th AROUND 6z-12z in the N PARTS, It's basically painting 2-3" for everyone.But i'm sure it will change many more times.Few clippers here and there but you got to get through the dry spell for a few days by the looks right now.

[John1122]

If it's sticking with the 29th I'll be quite pleased. The constant tease of storms that stay post-200 is like the greyhounds chasing the rabbit at the race track.

[jaxjagman]

If it's sticking with the 29th I'll be quite pleased. The constant tease of storms that stay post-200 is like the greyhounds chasing the rabbit at the race track.

Like the colder trend on the GFS.I was hoping to see something though not nothing but dryness..lol.These train of hp's are taking no names,nothing gets by them,annoying

[John1122]

BNA did mention the split flow possibly developing in the middle to latter half of next week, possibly providing some frozen fun for the Tennessee Valley. In the meantime, 7 more days of clippers, brief warm-ups and frigidity.

[John1122]

06z GFS is getting closer, brought the storm back to 204-216 after having it at 240+ 6 hours ago.

 

Not a block buster as of now, but hopefully it can stay on the field and actually happen. Could be some zr issues south of 40, the 850s are lined up along 40 on that run and the 2m 0 is on the Southern Tennessee border.

 

But all that will change multiple times. I just hope this is the start of reeling the storm into the closer range.

 

It follows that up with another potential storm about 36-48 hours later. 

[John1122]

And quite hilariously, all the cold retreats from the area in the longer range and a parade of heavy rain storms charge out of the GoM. Hopefully we can manage one decent event before that happens.

[jaxjagman]

Looks like a cold front is gonna stall out over the valley.Could be a couple days of non stop snow for all the valley starting the 29th-30th

[Stovepipe]

The 0z operational Euro has our storm hitting Thursday evening and bringing 1-4 inches of snow across TN with a bullseye in north MS, north AL, and SE TN.  Then on Saturday morning, another bigger system rolls through bringing totals up to 4-6 inches for the western half of TN, north MS, north AL, and TRI.  Details are given for entertainment purposes only.  The important thing is that the Euro is still showing storms for that time period and our region looks to reap the benefits.

 

I've not had a chance to look at ensembles yet but I imagine they are crazy good.

[weathertree4u]

The 0z operational Euro has our storm hitting Thursday evening and bringing 1-4 inches of snow across TN with a bullseye in north MS, north AL, and SE TN.  Then on Saturday morning, another bigger system rolls through bringing totals up to 4-6 inches for the western half of TN, north MS, north AL, and TRI.  Details are given for entertainment purposes only.  The important thing is that the Euro is still showing storms for that time period and our region looks to reap the benefits.

 

I've not had a chance to look at ensembles yet but I imagine they are crazy good.

 

Please take a look and post back; hopefully we can get at least one good plowable snow out of this cold pattern!

[John1122]

Not sure what source it uses, but Wunderground has me with a 70% chance of snow next Friday, subject of course to wild changes.

[Stovepipe]

Please take a look and post back; hopefully we can get at least one good plowable snow out of this cold pattern!

 

I looked over the 0z Euro ensembles.  As I suspected they look incredible across the region.  Out of the 51 members 22 or so show greater than 2 inches (most of those 22 are greater than 4 inches).  Some members go nuts and dump over a foot of snow.  This all happens around hour 192.

[tnweathernut]

Got those pretty Euro maps you showed yesterday Stove, or did you get your hand slapped for that?  You could always email them to the PM thread we have going.........haha

[jmundie]

GFS once again breaks down the PNA a bit too much - resulting in a cold rainstorm and dumping along the ohio river.

 

Good thing is - its still out past truncation. Can the arctic air move out that quickly? Sure. Will it. I sure hope not.

[weathertree4u]

GFS once again breaks down the PNA a bit too much - resulting in a cold rainstorm and dumping along the ohio river.

 

Good thing is - its still out past truncation. Can the arctic air move out that quickly? Sure. Will it. I sure hope not.

 

lets see waht the EURO says here is a few minutes; I wouldnt trust the GFS past a couple of days actually