Central US 2014-15 Winter Preseason Discussion

[Srain]

I like the look on the Euro's medium to long range. Looks like it has potential across the Southern Plains. Several impulses riding around the back end of the trough with cold air established....

And a potential sub tropical jet influence as a potentially weak tropical disturbance nears the Baja.

[JoMo]

12z Euro isn't as cold today. Still cold but not as cold. Still has probably snow with the Arctic front in the ND/MN area.  This run has a system undercutting the ridge in the west towards the end of the run. This system takes the southern route and depending on temps, might be a marginal frozen type of situation in the TX panhandle, N OK, into MO. If it were a month later, this would probably be a pretty big snowstorm. It'll probably be gone next run anyway.. lol

[Quixotic1]

Werk 5 snowcover on the CFS is a wernie dream.

[wildweatherman179]

And a potential sub tropical jet influence as a potentially weak tropical disturbance nears the Baja.

Yeah. If we can get the STJ involved at some point, we'll be in business but for now it appears any other moisture source is shut down.

[JoMo]

12z Euro ensembles have the continued ridge over the top and out west with a trough in the central and eastern US all the way through the run which ends on Nov 20th. This is a continued cold look.

[wildweatherman179]

18z GFS is darn close to developing an Arklatex style low at 12z on the 11th with the frontal boundary entering OK. Just shears out and shoves east just as fast as it develops.

[aggiegeog]

18z GFS is darn close to developing an Arklatex style low at 12z on the 11th with the frontal boundary entering OK. Just shears out and shoves east just as fast as it develops.

 Something like this is becoming more and more likely.

[Srain]

The 18Z parallel GFS attempts to develop a Coastal Low near Brownsville. In typical El Nino pattern regimes, a solution suggested by P GFS is not all that far fetched and will be interesting to watch as next week unfolds.

[wildweatherman179]

The 18Z parallel GFS attempts to develop a Coastal Low near Brownsville. In typical El Nino pattern regimes, a solution suggested by P GFS is not all that far fetched and will be interesting to watch as next week unfolds.

Not far fetched at all but just pretty useless if it can't develop before it gets pushed east.

[JoMo]

New JMA monthly is out. Looks like a continuation of what we are expecting for the first two weeks with the ridge in the west and troughing in the central and east. Last run kind of busted since it was during the pattern shuffle (many models ended up wrong)

 

The third and fourth week have more troughing farther north and some ridging off the east coast.

http://ds.data.jma.go.jp/tcc/tcc/products/model/map/1mE/map1/zpcmap.php

 

 

 

 

 

The 12z Euro ensembles today had the troughing over the central and east and the ridge in the west. However, by the end of the run on the 20th and 21st, there are signs the trough might be pushing a bit farther east into the eastern US. The control run suggests this might be because of a storm system dropping into the SW US by the end of the run.

 

 

Excited for the new Euro Weeklies later!

[wildweatherman179]

So you thinking maybe a west - central US trough with a southeast ridge heading into December?

[JoMo]

Weeklies are in and...

 

Troughing in the eastern and central US starts to pull back to the west around the 21/22nd or so but this is temporary (probably due to a storm system) and troughing redevelops in the central US and gradually pulls back west into roughly the western 1/2 of Canada and western 1/2 of the US by Nov 29th or so. The run ends with a trough off the west coast into the southwest and parts of the southern US on Dec 7th or so.

 

850 MB temps are cool/cold over the central US until Nov 30th into early Dec but there are signs that warmups/cooldowns happen with each storm system that passes by.

 

The control run is active. Looking at individual storm systems passing  through the Plains producing low surface pressure after the 300 hour mark..There's one the 18th/19th, 21st/22nd, 24th/25th (up near Canada border), 28th/29th, Dec 3rd/4th, and a mess of storm systems on the 6th-7th which is the end of the run.

 

So it looks active as we head into the last part of Nov into early Dec, but it doesn't look like wall to wall cold like next week. 

[wildweatherman179]

Great update man. I appreciate it!

[Srain]

All system are go for a pleasant weekend and the upper low currently just S of the Big Bend finally weakens and shears out. The pesky upper low which helped in steering the remnants of EPAC TC Vance NE across Texas brought and 8 foot rise in the Edwards Aquifer in a 48 hour period. This sort of steady rainfall was sorely needed across Central Texas. A cold front will arrive on Saturday reinforcing the pleasant Fall temperatures before the big pattern change we've all heard about by now ahead for next week.

 

 

The Global Ensembles and Operational computer guidance is in remarkably good agreement the former Super Typhoon Nuri will transition into a powerful Extratropical Storm near the Bering Sea. In the water vapor satellite imagery above, the storm is now entering the far upper left of the imagery and should wrap up and be rather impressive via satellite visible pictures over the weekend into Monday. Winds near or above 80 MPH with wave heights nearing 50 feet are forecast and expect near the Aleutian Island and the Bering Sea. The Super Storm will buckle the jet stream and allow very impressive cold air that has been building across Eurasia/Siberia due to extremely heavy October snowfall near record territory to be pulled across the Arctic into North America and spill very far south into Texas, Mexico and eventually into the Yucatan and Cuba later next week. The Canadian Prairies have been getting snow over the past several weeks, but the Northern/Central Plains are lacking any snow, so airmass modification will occur. That said the coldest air of the season will plunge S along and E of the Continental Divide and remain entrenched with reinforcing shots of cold air with the fast moving Northerly flow aloft and embedded upper air energy (shortwaves) bring cold fronts in fairly rapid progression during next week. The teleconnection indices are aligning in a very impressive fashion that bring a very -AO (-4+) -NAO (-1.5+) -EPO (-4+) + PNA (+3) regime together next week and just beyond the mid November timeframe. What this means for the Southern Plains and Texas is a Ridge of High Pressure build off the West Coast into Eastern Alaska into the Arctic while a very deep trough develops across Central and Eastern North America. The Pattern become blocked across the Atlantic which would allow the cold air to sweep E and miss our Region as we see in most Fall and Winter patterns. The fly in the ointment is the sub tropical jet across the Pacific and what it may or may not bring as El Nino continues to unfold.

There is convection associated with a tropical disturbance (96E) several hundred miles off the W Coast of Mexico and the track guidance is suggesting this disturbance remains rather weak, but does turn it NE toward the Pacific Coast of Mexico next week. At the same time the computer guidance is 'sniffing' a robust piece of upper level energy (shortwave) under cutting the Ridge out W and developing a low pressure system along the front range of the Southern Rockies near New Mexico/Colorado. This happens later next week (around November 15th -17th) after the Arctic front arrives late on Monday into Tuesday. IF, and it is a big if the models such as the European are correct a big Winter like storm may develop across the Panhandle and cross the Southern Plains ushering in even colder air and build a snow cover across the Plains. If that happens, then much less airmass modification is a possibility. The guidance is suggesting another stronger Arctic front following this energy, so we have a lot of moving parts to follow on our weather plate and should lead to some interesting discussions as next week unfolds.

 

 

[Quixotic1]

Operational GFS 12z agrees.  Winter fun. 

[Srain]

Technical analysis from the Climate Prediction Center for the Day 6 to 10 period...

 

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST FRI NOVEMBER 07 2014
 
6-10 DAY OUTLOOK FOR NOV 13 - 17 2014
 
TODAY'S MODEL SOLUTIONS ARE IN EXCELLENT AGREEMENT IN PREDICTING A VERY 
AMPLIFIED 500-HPA FLOW PATTERN OVER MOST OF THE FORECAST DOMAIN. THE MODELS 
AGREE IN PREDICTING A STRONG TROUGH OVER THE BERING SEA. DOWNSTREAM OF THIS 
FEATURE, RIDGING IS FORECAST ALONG THE WEST COAST OF NORTH AMERICA WHILE A DEEP 
TROUGH IS PREDICTED OVER THE EASTERN AND CENTRAL CONUS. THE DETERMINISTIC RUNS 
FROM THE GFS AND ECMWF ARE GENERALLY IN GOOD AGREEMENT WITH THEIR RESPECTIVE 
ENSEMBLE MEAN SOLUTIONS. HOWEVER, TODAY'S 0Z DETERMINISTIC ECMWF AND TODAY'S 
DETERMINISTIC 12Z GFS RUNS INDICATE A WESTWARD SHIFT OF THE PATTERN OVER THE 
CONUS AND PULL THE PREDICTED TROUGH OVER EASTERN NORTH AMERICA MORE TOWARD THE 
CENTER OF THE COUNTRY. THIS WESTWARD SHIFT IS SUPPORTED BY TELECONNECTIONS FROM 
A POSITIVE HEIGHT ANOMALY CENTER OVER NORTHWESTERN CANADA IN TODAY'S MANUAL 
HEIGHT BLEND. TODAY'S MANUAL 500-HPA HEIGHT BLEND IS COMPOSED PRIMARILY OF THE 
ENSEMBLE MEAN SOLUTIONS AND IS BASED ON CONSIDERATIONS OF RECENT SKILL AND ON 
ANALOG CORRELATIONS, WHICH MEASURE HOW CLOSELY THE FORECAST PATTERN RESEMBLES 
CASES THAT HAVE OCCURRED IN THE PAST.   
 
THE DEEP TROUGH PREDICTED OVER EAST-CENTRAL NORTH AMERICA STRONGLY FAVORS 
BELOW-NORMAL TEMPERATURES FOR MOST OF THE CENTRAL AND EASTERN CONUS. HOWEVER, 
NEAR-NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE FLORIDA PENINSULA AHEAD 
OF THE PREDICTED TROUGH AXIS. FORECAST RIDGING ALONG THE WEST COAST FAVORS 
ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE SOUTHWESTERN CONUS. ABOVE-NORMAL 
TEMPERATURES ARE ALSO FAVORED FOR ALASKA UNDERNEATH ANOMALOUS SOUTHERLY FLOW 
AHEAD OF THE TROUGH PREDICTED OVER THE BERING SEA. 
 
MOIST FLOW AHEAD OF THE PREDICTED BERING SEA TROUGH FAVORS ABOVE-MEDIAN 
PRECIPITATION FOR MUCH OF WESTERN AND SOUTHERN ALASKA. CONVERSELY, BELOW-MEDIAN 
PRECIPITATION IS FAVORED FOR PARTS OF THE WESTERN CONUS IN ASSOCIATION WITH 
PREDICTED RIDGING. PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ARE ALSO 
ENHANCED FOR MUCH OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY DUE TO SUBSIDENCE 
ASSOCIATED WITH THE TROUGH PREDICTED OVER THE EAST-CENTRAL CONUS. THERE IS THE 
POTENTIAL FOR AN EAST COAST STORM TRACK AHEAD OF THE TROUGH AXIS RESULTING IN 
ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION ALONG THE IMMEDIATE 
EASTERN SEABOARD. HOWEVER, THERE IS STILL MUCH UNCERTAINTY AS TO THE DETAILS OF 
ANY SHORTWAVE TROUGHS THAT MAY DEVELOP. ABOVE-MEDIAN PRECIPITATION IS ALSO 
FAVORED FOR THE GULF COAST REGION AND PARTS OF THE SOUTHERN PLAINS AND SOUTHERN 
ROCKIES AROUND THE BASE OF THE PREDICTED LONGWAVE TROUGH OVER EAST-CENTRAL 
NORTH AMERICA.
 
TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS ENSEMBLE MEAN 
CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 10% 
OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 20% OF TODAY'S 0Z EUROPEAN 
ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN 
CENTERED ON DAY 7, 15% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 
15% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8 
 
 
MODEL OF THE DAY: 0Z ECMWF ENSEMBLE MEAN 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: MUCH ABOVE AVERAGE, 5 OUT OF 5, 
DUE TO GOOD MODEL AGREEMENT AND A PREDICTED AMPLIFIED PATTERN.
 

 

 

 

[JoMo]

So anyone seen the -EPO? It's off the chart. Brrrr

 

 

 

The 'new' GFS sure has a lot of snow during the next 10 days.

 

[aggiegeog]

If the upgraded GFS is correct November will be incredible. That -EPO tank is crazy.

[wildweatherman179]

If the upgraded GFS is correct November will be incredible. That -EPO tank is crazy.

Yeah. You know it's a pretty big deal when the chart isn't big enough.

[JoMo]

JB sounded a bit shaken today. Apparently the new Euro seasonal has a cold west and central US with a ridge in NW Canada but there's a SE ridge showing up. Anyone find any more info on what the new Euro seasonal shows?

[The Waterboy]

Why did he sound shaken? Because a SE ridge will warm up the East Coast and his forecast could be a huge bust?

[Kory]

Why did he sound shaken? Because a SE ridge will warm up the East Coast and his forecast could be a huge bust?

He has known biases that make me take any of his forecasts with a grain of salt.

[Srain]

JB sounded a bit shaken today. Apparently the new Euro seasonal has a cold west and central US with a ridge in NW Canada but there's a SE ridge showing up. Anyone find any more info on what the new Euro seasonal shows?

Remember when November was going to be mild via Euro Seasonal a month ago...

[wildweatherman179]

JB sounded a bit shaken today. Apparently the new Euro seasonal has a cold west and central US with a ridge in NW Canada but there's a SE ridge showing up. Anyone find any more info on what the new Euro seasonal shows?

I don't have any more info on what it shows but this pattern adjustment is not entirely unexpected my me. The guidance was all too far east based to begin with when it did finally show cold. Something that we have to sort of remember is that This pattern is more tropical driven of sorts than a more 'natural' type pattern. He needs to take his own advice sometimes and use guidance for what it is. Use reasoning for the rest.

[JoMo]

Why did he sound shaken? Because a SE ridge will warm up the East Coast and his forecast could be a huge bust?

 

It was just not expected. To be fair it did a terrible job last year, and as Srain pointed out, last month as well. JB says the only one that matches is 1951-1952 and it had a different SST look in the west then what we currently have. They are sticking with their forecast for now.

 

However, last month's JMA had a similar trough in the west and I believe one other seasonal model did as well. 

[The Waterboy]

12z GFS looks good for next weekend. Especially in Texas Panhandle and Western OK. Where do we find the Parallel GFS and are there snow maps available?

[Srain]

12z GFS looks good for next weekend. Especially in Texas Panhandle and Western OK. Where do we find the Parallel GFS and are there snow maps available?

 It is available on the American Weather Model Center as well as Tropical Tidbits...

 

http://www.tropicaltidbits.com/analysis/models/

 

WxBell is offering a free 7 Day trial for the Parallel GFS as well.

[The Waterboy]

Thanks Srain!

[Srain]

Nice blocking regime in the 12Z extended range Euro today.

 

 

[Snowman99]

EUro looks like mid winter.  Has a couple inches or more of snow over most of Missouri with lows getting into the single numbers over that snow cover in days 9 and 10. Crazy crazy stuff.