Winter 2013-14 Pattern Discussion

[packbacker]

If you were to take the average of the Euro and GFS at day 5/6 we would be in business.

[SN_Lover]

I think we need to get something next week or we're looking at the mid to late January (at least) for our next wintery threat. The PNA now looks bad in the LR with a decidedly negative look. As others have stated the AO still looks good but that will not help the SE without the PNA or NAO on our side.   

I agree. Hopefully we see a good snowstorm by the end of winter 

[BullCityWx]

I'll take this storm being squashed for now. The odds are in favor of a north trend given our pattern.

[GaWx]

I'll take this storm being squashed for now. The odds are in favor of a north trend given our pattern.

 

 About all that would be needed for a sig. SE winter storm would be a WSW 500 mb flow instead of a W flow. that would give us the north trend you mentioned.

 

 Also, the low is better off staying weak imo. It is already producing tons of QPF as it is modeled here. Weak lows have produced big winter storms many times and they limit WAA.

[El Kabong]

 About all that would be needed for a sig. SE winter storm would be a WSW 500 mb flow instead of a W flow. The low is better off staying weak. It is already producing tons of QPF as it is modeled here.

Larry,

 

If the moisture begins to trend north, where is the Euro showing the cut-off line for frozen precip?  Is it looking like ATL and points north, or is the cold air far enough south to affect MCN?  Thanks as always for your analysis.

[GaWx]

Larry,

 

If the moisture begins to trend north, where is the Euro showing the cut-off line for frozen precip?  Is it looking like ATL and points north, or is the cold air far enough south to affect MCN?  Thanks as always for your analysis.

 

The 0Z 850 line makes it down to Macon just as the precip exits south GA. Precip makes it as far north as Columbus to Perry to Statesboro to Charleston.

[El Kabong]

The 0Z 850 line makes it down to Macon just as the precip exits south GA. Precip makes it as far north as Columbus to Perry to Statesboro to Charleston.

What a surprise!  The cold air gets here as the moisture is leaving   We must live in the South!  Anyway, thanks for the analysis.  Still plenty of time for things to change.

[Cold Rain]

Euro at 240 is miles better than the GFS at 240. Both the GFS and the CMC have the Lakes low for the post NYD storm, which the Euro and the UKMET (best I can tell) do not.

[BullCityWx]

It gets real cold after the storm

[burgertime]

I'll take this storm being squashed for now. The odds are in favor of a north trend given our pattern.

Exactly we now see what the ENS was seeing with potential. GFS is also close but everything was strung out. This could get fun to watch.

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[tnweathernut]

This current storm for this weekend is a perfect example of what happens without a -NAO. 

 

I have a couple of friends who are going to New Orleans to watch an NFL game Sunday, leaving today, and coming back on Monday.  Several days ago they asked me about the weather there and down and back.  It looked mostly sunny, with the fairly dry cold front finally sagging toward the southeast Monday.  New Orleans is now projected to get between 1 and 2 inches of rain, and that heavy rain has it's sights set on the southern apps.  Just three days ago there wasn't a hint of precip on the modeling for New Orleans or the southern apps as the low was projected very weak and way down in the gulf.........

 

Just food for thought as we head toward the Jan 2nd system.
 

[Wow]

Exactly we now see what the ENS was seeing with potential. GFS is also close but everything was strung out. This could get fun to watch.

Sent from my HTC One

 

Need to see a clear separation between the northern and southern energy. Right now it's phasing way back over the plains and sending that big primary low up to the lakes before popping a secondary in the gulf.   Less phase & stronger southern s/w.. the northern s/w shears out, and HP can build in over the southern low.  Still not seeing it here.

[NCCatawba]

NWS Greenville

 

as of 150 PM Friday...a complex and not too confident forecast is in
store through the ext period.

 

The latest GFS showcases an active pattern with an aggressive southern
stream short wave and the development of an inverted trough off the atl.
Thus...fluxing in very good low level moisture combined with isent lift
across the eastern zones after 03z Tuesday. The consall and consraw model
blends are both on board with this scenario...while the old 00z
European model (ecmwf) is a dry outlier. With some support seen on the 12z CMC...the
pop grids were bumped to low end chances Monday night across the
Piedmont including the clt area. Min temperatures should have no problem
falling below freezing with the California surface high in place...so snow and a
wintry mix are the likely p/types through day break. Its too early
to conjecture on accums...but right now it looks to be low end.

The GFS continues with an active upper pattern
Wednesday night...bringing in an extended period of streamwise vorticity and
perhaps instigating weak coastal cyclogenesis. This surface low is not
well supported by the other op models but it has some support from
the gefs mean. In any case...slight probability of precipitation were introduced to the forecast
cwfa/wide. This will feature -shra during the day and a diurnal
wintry mix overnight as moisture lifts over the cold dome. 

[burgertime]

 

Need to see a clear separation between the northern and southern energy. Right now it's phasing way back over the plains and sending that big primary low up to the lakes before popping a secondary in the gulf.   Less phase & stronger southern s/w.. the northern s/w shears out, and HP can build in over the southern low.  Still not seeing it here.

I hear ya and that IMHO could happen given how darn inconsistent modeling has been. Of course more likely this runs up the apps or is just rain if the Euro is right. I guess from the Euro it just looks like good timing which is never something to count on. All winter and summer systems coming through the Gulf have been amped up and full of moisture I would have to guess this would be the same and if that cold front can roll in at the same time luck just might be on our side.

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[Wow]

Sure hope the Canadian is on to something here by 240 hrs with the western ridge/Greenland block in place and the PV crashing in with -40C core 850mb temps  

 

 

[packbacker]

Both the Euro ENS mean and control run have a weak low off the GA coast, looks a little to east, probably gives the coast a good snow event.

[franklin NCwx]

Both the Euro ENS mean and control run have a weak low off the GA coast, looks a little to east, probably gives the coast a good snow event.

also no lakes low either. Two highs, one of the lakes and the other over eastern Canada.

[packbacker]

also no lakes low either. Two highs, one of the lakes and the other over eastern Canada.

Matches up well with the Op. It's such a progressive pattern that timing of the low needs to be perfect.

[Poimen]

And the 84 hour NAM is indicating snow over central/western NC, for what its worth.

 

If somehow we can pull off some light snow on New Year's Eve and then get a bigger thump a few days later, that would be great. Not saying it will happen, just trying to be optimistic.

 

[SnowNiner]

And the 84 hour NAM is indicating snow over central/western NC, for what its worth.

 

If somehow we can pull off some light snow on New Year's Eve and then get a bigger thump a few days later, that would be great. Not saying it will happen, just trying to be optimistic.

 

 

 

Yeah, NWS actually put that in the CLT forecast and mentioned it in the forecast discussion.  Pretty matter of factly like it's a done deal that the CWA would have light accumulations. 

 

If we get decent below freezing accumulating snow 12/31 then 1/2 I'm good for the winter!!

[Shack]

Both the Euro ENS mean and control run have a weak low off the GA coast, looks a little to east, probably gives the coast a good snow event.

What time frame is the Ensemble showing this?

[SnowNiner]

also no lakes low either. Two highs, one of the lakes and the other over eastern Canada.

 

I don't think the GEFS mean had the low in the lakes either.  Something is going to pop this weekend I think.  Somebody's going to be tracking a winter storm by Sunday in the SE.  There's just too many clues. 

[FallsLake]

Yeah, NWS actually put that in the CLT forecast and mentioned it in the forecast discussion.  Pretty matter of factly like it's a done deal that the CWA would have light accumulations. 

 

If we get decent below freezing accumulating snow 12/31 then 1/2 I'm good for the winter!!

Here's the simulated radar at hour 84:

 

[dsaur]

The 0Z 850 line makes it down to Macon just as the precip exits south GA. Precip makes it as far north as Columbus to Perry to Statesboro to Charleston.

That sounds real good to me this far out.  Much easier to get them to come up some in the intervening days   Just need to let it percolate for 10 runs then see what we've got.  Meanwhile, there looks to be no lack of rain coming, after nothing for 10 days just two day ago.  If we see this inside 3 days, we've got a chance, lol.  I'm getting clouds now so I'm thinking it may actually rain again. Not bad for "nothing for 10 days" so recently   Tony

[packbacker]

What time frame is the Ensemble showing this?

Day 6/7, roughly same as Op.

[Shawn]

That sounds real good to me this far out.  Much easier to get them to come up some in the intervening days   Just need to let it percolate for 10 runs then see what we've got.  Meanwhile, there looks to be no lack of rain coming, after nothing for 10 days just two day ago.  If we see this inside 3 days, we've got a chance, lol.  I'm getting clouds now so I'm thinking it may actually rain again. Not bad for "nothing for 10 days" so recently   Tony

 

If the OP Euro is right, it's actually an amazing run because of that North trend of precip that always tends to happen.  Euro is in it's golden area of forecasting, and has cold temps with a nice batch of precip to the South.  This is just screaming a possible deep south snow at me showing up as we get closer.  Even possibly for us.

[NCCatawba]

Might be able to squeeze out a tornado in the east according to NWS Raleigh.

 

It's Worth noting that recent model runs have been trending toward a little more cape
(though still skinny) in the forecast soundings across our eastern
zones at locations such as Fay and rwi...but still below 500j/kg. If
these trends continue...so will our confidence in the potential for
some strong to severe thunderstorms (rotating cells with severe wind
the main threat and potential for isolated tornadoes) across our
eastern zones (mainly I-95 corridor eastward) early Sunday afternoon
just ahead of surface low as it tracks across our area. 

[tnweathernut]

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST FRI DECEMBER 27 2013

6-10 DAY OUTLOOK FOR JAN 02 - 06 2014

TODAY'S ENSEMBLE MEAN FORECASTS SHOW VERY GOOD AGREEMENT ON THE EXPECTED
500-HPA HEIGHT PATTERN FOR THE 6-10 DAY PERIOD OVER NORTH AMERICA. AN ELONGATED
TROUGH IS FORECAST TO STRETCH FROM NEAR HUDSON BAY TO SOUTHEASTERN CANADA,
DOMINATING MOST OF THE CONUS, WHILE A RIDGE IS EXPECTED OVER THE EASTERN
PACIFIC STRETCHING NORTHWARD TO NORTH OF ALASKA. RECENT DETERMINISTIC GFS AND
ECMWF SOLUTIONS ARE IN RELATIVELY GOOD AGREEMENT WITH THEIR RESPECTIVE ENSEMBLE
MEANS, ALTHOUGH THE DETERMINISTIC RUNS ARE GENERALLY MORE AMPLIFIED WITH
INDIVIDUAL SHORTWAVE FEATURES.

THE ENSEMBLE SPAGHETTI DIAGRAMS GENERALLY INDICATE LOW TO MODERATE SPREAD OVER
MOST OF THE CONUS, BUT MODERATE TO LARGE SPREAD IS NOTED OVER THE EASTERN
PACIFIC AND SOUTHWESTERN U.S. THIS SPREAD INDICATES LARGE UNCERTAINTY WITH
RESPECT TO THE ORIENTATION OF THE RIDGE FORECAST OVER THE EASTERN PACIFIC AND
THE AMOUNT OF SHORTWAVE ENERGY THAT IS ABLE TO UNDERCUT THE RIDGE. THE PNA
INDEX WHICH HAS RECENTLY BEEN CLOSE TO ZERO IS EXPECTED TO BE VERY WEAKLY
POSITIVE OR NEAR ZERO THROUGH DAY 14. THE NAO INDEX WHICH HAS RECENTLY BEEN
WEAKLY POSITIVE IS FORECAST TO BE CLOSE TO ZERO BY DAY 7, BE WEAKLY POSITIVE BY
DAY 10, AND REMAIN SLIGHTLY POSITIVE THROUGH DAY 14. TODAY'S BLEND CHART
INDICATES NEAR TO ABOVE-NORMAL HEIGHTS OVER MOST OF THE WESTERN CONUS, ALASKA,
THE ALASKAN PANHANDLE, AND THE ALEUTIANS, WHILE NEAR TO BELOW-NORMAL HEIGHTS
ARE ANTICIPATED OVER THE EASTERN CONUS AND PARTS OF THE NORTHERN PLAINS.

BELOW-NORMAL HEIGHTS AND ANOMALOUS NORTHWESTERLY FLOW ENHANCE PROBABILITIES FOR
BELOW-NORMAL TEMPERATURES FOR MUCH OF THE EASTERN HALF OF THE CONUS.
ABOVE-NORMAL HEIGHTS OFFSET BY AREAS THAT HAVE SNOW COVER FAVOR NEAR-NORMAL
TEMPERATURES FOR A SMALL PORTION OF THE CENTRAL GREAT BASIN. ABOVE-NORMAL
HEIGHTS TILT THE ODDS TO ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE REMAINDER OF
THE WESTERN CONUS. ANOMALOUS SOUTH/SOUTHWESTERLY FLOW AND ABOVE NORMAL HEIGHTS
ENHANCE PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR PARTS OF WESTERN ALASKA
AND THE ALEUTIANS.

LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY,
LEADS TO ENHANCED PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION ALONG PARTS OF
THE GULF COAST, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, AND THE SOUTHEAST. A
GREAT DEAL OF UNCERTAINTY EXISTS AMONG THE MODEL SOLUTIONS REGARDING EVOLUTION
OF THIS LOW PRESSURE SYSTEM. SHORTWAVE ENERGY RIDING OVER THE TOP OF, OR
THROUGH THE RIDGE FORECAST OVER WESTERN NORTH AMERICA TILTS THE ODDS TO
ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE NORTHERN ROCKIES, NORTHERN PLAINS,
UPPER MISSISSIPPI VALLEY AND GREAT LAKES. ANOMALOUS SOUTHERLY/SOUTHWESTERLY
FLOW ENHANCES PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION FOR PARTS OF
NORTHWESTERN ALASKA. ABOVE NORMAL HEIGHTS TILT THE ODDS TO BELOW MEDIAN
PRECIPITATION FOR PARTS OF SOUTHERN ALASKA. ABOVE-NORMAL HEIGHTS AND ANOMALOUS
NORTH/NORTHEASTERLY FLOW FAVORS BELOW-MEDIAN PRECIPITATION FOR THE SOUTHWESTERN
CONUS, WHILE ANOMALOUS NORTHWESTERLY FLOW ENHANCES PROBABILITIES FOR
BELOW-MEDIAN PRECIPITATION FOR PARTS OF THE CENTRAL ROCKIES AND CENTRAL AND
SOUTHERN PLAINS.

TODAY'S OFFICIAL 500-HPA BLEND CONSISTS OF 5 PERCENT OF TODAY'S OPERATIONAL 6Z
GFS CENTERED ON DAY 8...15 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON
DAY 8...15 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...20
PERCENT OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8...15 PERCENT OF
TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8...5 PERCENT OF YESTERDAY'S
OPERATIONAL 12Z ECMWF CENTERED ON DAY 7...15 PERCENT OF YESTERDAY'S 12Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7...AND 10 PERCENT OF YESTERDAY'S 12Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 7.

MODEL OF THE DAY: TODAY'S 00Z ECMWF ENSEMBLE MEAN 

 

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE ENSEMBLE MEANS AND FAIR AGREEMENT AMONG THE
TEMPERATURE TOOLS OFFSET BY RELATIVELY POOR AGREEMENT AMONG THE PRECIPITATION
TOOLS. 

 

From our TN Valley subforum.................I guess this sounds as good as can be from this far out.

[packbacker]

Euro ens members still look good, over half, a couple more than 0z, show snow for the area.

[Tacoma]

will there be any snow for n ga. and wnc?