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2013 Fall Medium Range Discussion


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Rare coast to coast below temps in the medium range, including Canada seems to be on tap. Temps anomalies from the 15th-25th will be interesting to look at...my guess is that the areal coverage of the cold anomalies for that period will be extraordinary.

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Rare coast to coast below temps in the medium range, including Canada seems to be on tap. Temps anomalies from the 15th-25th will be interesting to look at...my guess is that the areal coverage of the cold anomalies for that period will be extraordinary.

As expected with all the uncertainty in the medium range, WSR (Winter Storm Recon) has been tasked for the Pacific once again due to all that uncertainty in the upcoming pattern and just what the effects will be across the Country.

 

 

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

0100 PM EST SAT 09 FEBRUARY 2013

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

         VALID 10/1100Z TO 11/1100Z FEBRUARY 2013

         WSPOD NUMBER.....12-071

 

I.  ATLANTIC REQUIREMENTS

    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

    2. SUCCEEDING DAY OUTLOOK:  ALASKAN-BASED TRACK

       P16/ DROP 8 (40.0N 164.0W)/ 12/0000Z

    3. ADDITIONAL DAY OUTLOOK:  POSSIBLE

       P23/ DROP 8 (47.0N 175.0W)/ 13/0000Z

 

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Nice work Don..

 

Unfortunately the 67 analog failed to deliver the goods here ( like it did in Jan 67 aka Chicago blizzard that dumped 28.6" inches here ) unlike the northeast. Oh well.

 

Enjoy the snowstorm. :)

Unfortunately, analogs are far from perfect. In terms of snowfall opportunities, Chicago missed out on the December 25-28 blizzard. Had the storm tracked a little more to the south and east, snow-starved Chicago could have had a big snowstorm. Around the anniversary of the 1967 blizzard, there were only light snows in Chicago. Hopefully, the Windy City will get a more decent snowstorm this month.

 

There were some differences with respect to the recent Northeast blizzard. That storm brought only a small snowfall to Philadelphia (unlike 1967).

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Unfortunately, analogs are far from perfect. In terms of snowfall opportunities, Chicago missed out on the December 25-28 blizzard. Had the storm tracked a little more to the south and east, snow-starved Chicago could have had a big snowstorm. Around the anniversary of the 1967 blizzard, there were only light snows in Chicago. Hopefully, the Windy City will get a more decent snowstorm this month.

 

There were some differences with respect to the recent Northeast blizzard. That storm brought only a small snowfall to Philadelphia (unlike 1967).

it looks like an average of 1962 and 1967 Don...1967 had more chances but they both had big March events...1967 had much more snow because the Ash Wed. storm just grazed the city...

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MJO heading through phases 2 and 3, good for troughing western 1/3 of country right?

Not phase 2...it's probably one of the coldest phases for the eastern half of the country. Phase 3 I think favors some west coast troughing and east coast ridging, but the real unfavorable phases for cold in the east are 4-7.

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Recently, there has been speculation concerning a possible chance for a major East Coast snowstorm for the February 17-19 timeframe. Fueling that speculation was a forecast on the GFS ensembles for major trough amplification in eastern North America around that timeframe. However, odds are much against such an outcome. There is good agreement among the GFS, Canadian, and ECMWF guidance that the MJO will likely be in Phase 4 during that timeframe.

 

Phases 4 and 5 do not favorable phases of KU-type snowstorms, even as the March 1993 superstorm occurred during Phase 4 and the 1979 President's Day snowstorm occurred during a transition from Phase 3 to Phase 4.

 

FebMarchMJOKU_zps6b33dacd.jpg

 

The above chart shows that KU snowstorms are greatly overrepresented in Phases 1-3 and somewhat overrepresented in Phases 6-8. In contrast, they are greatly underrepresented in Phases 4-5. If that data is reasonable and the MJO forecasts are accurate, and exceptions can occur, one probably won't see the chance of a KU snowstorm until the period beginning 2/21 at the earliest.

 

With Phases 6-8 perhaps representing the next chance for which such a storm can reasonably be considered, it should be noted that 83% of February-March KU storms during those MJO phases occurred with an amplitude of 1 or above. Moreover, all of the February-March KU storms that occurred during Phases 6-8 commenced when the Arctic Oscillation was negative (83% when the AO was -1 or below and 67% when the AO was -3 or below). Therefore, one would probably want to see prospects for blocking and preferably strong blocking by 2/21. There is some ensemble support for such an outcome in terms of blocking, but there is no strong ensemble consensus right now.

 

The near absence of KU snowstorms in Phases 4-5 does not mean no opportunities for snowfall. There have been moderate-to-significant storms that fell short of KU classification. There have also been near misses. Recent examples include February 6-7, 2003, February 3-4, 2009, and March 1-3, 2009.

 

In sum, I have little reason to depart from my thinking expressed earlier in this thread (e.g., #570) that the Ohio Valley, Mid-Atlantic region, and New England will see additional snows. That includes snowfalls after the modest 2/13-14 event. However, if one is hoping for a blockbuster East Coast event, one should not be looking to this weekend. I'm not surprised that the ECMWF is unimpressed with the 2/17-19 timeframe. Instead, better prospects might exist beginning around February 21 based on the MJO forecast and historic MJO data.

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Don, good analysis. The only thing I'll add is that I'm skeptical that the dynamical models are forecasting the transition into Phase 4 correctly. I could easily see us remain in Phase 3 through early next week, similar to the statistical guidance from Albany and Australia.

I agree that the MJO's progression might lag the dynamical guidance. Hopefully, it will.

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Recently, there has been speculation concerning a possible chance for a major East Coast snowstorm for the February 17-19 timeframe. Fueling that speculation was a forecast on the GFS ensembles for major trough amplification in eastern North America around that timeframe. However, odds are much against such an outcome. There is good agreement among the GFS, Canadian, and ECMWF guidance that the MJO will likely be in Phase 4 during that timeframe.

 

Phases 4 and 5 do not favorable phases of KU-type snowstorms, even as the March 1993 superstorm occurred during Phase 4 and the 1979 President's Day snowstorm occurred during a transition from Phase 3 to Phase 4.

 

FebMarchMJOKU_zps6b33dacd.jpg

 

The above chart shows that KU snowstorms are greatly overrepresented in Phases 1-3 and somewhat overrepresented in Phases 6-8. In contrast, they are greatly underrepresented in Phases 4-5. If that data is reasonable and the MJO forecasts are accurate, and exceptions can occur, one probably won't see the chance of a KU snowstorm until the period beginning 2/21 at the earliest.

 

With Phases 6-8 perhaps representing the next chance for which such a storm can reasonably be considered, it should be noted that 83% of February-March KU storms during those MJO phases occurred with an amplitude of 1 or above. Moreover, all of the February-March KU storms that occurred during Phases 6-8 commenced when the Arctic Oscillation was negative (83% when the AO was -1 or below and 67% when the AO was -3 or below). Therefore, one would probably want to see prospects for blocking and preferably strong blocking by 2/21. There is some ensemble support for such an outcome in terms of blocking, but there is no strong ensemble consensus right now.

 

The near absence of KU snowstorms in Phases 4-5 does not mean no opportunities for snowfall. There have been moderate-to-significant storms that fell short of KU classification. There have also been near misses. Recent examples include February 6-7, 2003, February 3-4, 2009, and March 1-3, 2009.

 

In sum, I have little reason to depart from my thinking expressed earlier in this thread (e.g., #570) that the Ohio Valley, Mid-Atlantic region, and New England will see additional snows. That includes snowfalls after the modest 2/13-14 event. However, if one is hoping for a blockbuster East Coast event, one should not be looking to this weekend. I'm not surprised that the ECMWF is unimpressed with the 2/17-19 timeframe. Instead, better prospects might exist beginning around February 21 based on the MJO forecast and historic MJO data.

Don, what do you think of Toronto's chances for getting another 4-6" snowfall before the month is through. The models look promising for next week!

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Don - is there a way to identify the conditions (AO/NAO, etc.) that prevailed prior to or during the KU events when the MJO was in Phases 4-5?

 

Prior to the March 1993 superstorm, the AO was positive and rising. It peaked at 3.984 on March 17, a few days after the superstorm. The AO was also positive and rising for the borderline KU November 1987 snowstorm. Both events saw the MJO in Phase 4.

 

The MJO was in Phase 5 for the Boxing Day blizzard of 2010. The AO was severely negative.

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Don - your analysis is extremely helpful at this time of year, as the big question in VT turns to "when are you going to tap your trees?" The old saw was to tap trees around Town Meeting Day (first Tuesday in March), but in recent years folks who tapped at that time missed out on early sap runs. But if you tap too early and then the weather turns sharply colder, the tap might dry out.

A second reason this analysis is good involves the agriculture industry, especially for those who don't heat their greenhouses to get an early start. No sense starting seeds if the analysis looks like significant cold is coming. But when all the data suggests the opposite, it's time to roll up the sleeves and get to work.

Edited for grammar.

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Don, terrific post, right on que the 18z GFS is painting a picture for the Feb 22-23 timeframe, high pressure in SE canada, confluence, and an "evil" wave out west.

 

attachicon.gif18zgfs.gif

Thanks Highzenberrg. It will be interesting to see how things turn out. I believe if there is a credible threat, the signal should become persistent as one approaches the timeframe.

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Don - your analysis is extremely helpful at this time of year, as the big question in VT turns to "when are you going to tap your trees?" The old saw was to tap trees around Town Meeting Day (first Tuesday in March), but in recent years folks who tapped at that time missed out on early sap runs. But if you tap too early and then the weather turns sharply colder, the tap might dry out.

A second reason this analysis is good involves the agriculture industry, especially for those who don't heat their greenhouses to get an early start. No sense starting seeds if the analysis looks like significant cold is coming. But when all the data suggests the opposite, it's time to roll up the sleeves and get to work.

Edited for grammar.

'Weather" is less important than you'd think. Don't start much before the first new moon after the last full moon in February even if the sap seems to be flowing. PM me if you'd like more advice than that.

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I made a list of the biggest NYC snowstorms since 1950 and what the NAO/AO/PNA/ENSO was at the time....

snowstorm...date......AO......PNA......NAO......Enso/MEI....
12" 03/18/1956....0.470....0.186.....-0.225.....La Nina
12" 03/20/1958...-2.522....0.067.....-0.830.....El Nino
14" 12/21/1959....1.266....0.114......1.032.....Neutral-
15" 03/03/1960...-1.265...-0.834......0.249.....Neutral-
15" 12/11/1960...-0.343....1.527.....-0.316.....Neutral-
10" 01/19/1961...-1.506....1.587......0.392.....Neutral-
18" 02/03/1961....0.621....0.489.....-0.126.....Neutral-
13" 01/12/1964....0.385....0.654.....-1.180.....Weak El Nino
15" 02/06/1967....1.180....0.732......0.230.....Weak La Nina
15" 02/09/1969...-3.114...-0.325......0.044.....Weak El Nino
14" 01/19/1978...-0.347....0.262......0.230.....Weak El Nino
18" 02/06/1978...-3.014....1.188.....-0.093.....Weak El Nino
13" 02/19/1979...-0.697...-0.042......0.254.....Neutral+
18" 02/11/1983...-1.806....0.845.....-0.567.....El Nino
10" 03/13/1993....0.764...-0.179......0.472.....Weak El Nino
13" 02/11/1994...-0.862...-0.454......0.927.....Neutral+
11" 02/04/1995....1.429....1.604......0.437.....El Nino
20" 01/08/1996...-1.200....0.447.....-0.392.....Weak La Nina
11" 02/16/1996....0.163...-0.421......0.534.....Weak La Nina
12" 12/30/2000...-2.354....1.075.....-0.537.....Weak La Nina
20" 02/16/2003....0.128....0.681......0.836.....El Nino
14" 12/05/2003....0.265....0.784.....-0.197.....Neutral+
10" 01/25/2004...-1.686....0.164.....-0.541.....Neutral+
14" 01/25/2005....0.356....1.098.....-0.035.....El Nino
27" 02/11/2006...-0.156....1.658......0.136.....Neutral-
11" 12/19/2009...-3.413....0.549.....-1.833.....El Nino
10" 02/09/2010...-4.266....0.622.....-1.136.....El Nino
21" 02/25/2010...-3.818....0.087.....-0.219.....El Nino
20" 12/26/2010...-2.631...-0.284.....-0.834.....La Nina
19" 01/26/2011...-1.683....1.233.....-0.142.....La Nina

11" 02/09/2013...-0.500....0.250......0.230.....neutral- estimated indicies...

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 For those who may be interested, I did a study of all major Atlanta and Raleigh S/IP since 1974 (21 storms) and found there to be no detectable correlation between the MJO phases and storm frequency. I bolded notable major SE winter storms that were in the "warm" phases.

 

-1/9-10/2011: started phase 6 and moved to 5

-12/25-6/2010: phase 5

-2/12/2010: phase 8 

-1/29-30/2010: phase 7-2/26-7/2004: phase 5

-3/1/2009: phase 4 

-1/2-3/2002: phase 7  -8

-1/24-5/2000: COD

-1/6-7/1996: COD

-3/13/1993: phase 4

-1/18/1992: phase 8

-2/17-8/1989: COD

-1/17/1988: phase 2

-2/27/1987: phase 7

-2/16-7/1987: COD

-1/22/1987: phase 3

-2/5-6/1984: phase 3

-3/24/1983: COD

-1/12-14/1982: COD

-3/1-2/1980: COD

-2/17-18/1979: started phase 3 and moved to COD

 

--------------------------------------------------

 

"Cold" phases (8/1/2/3): 6 storms

"Warm" phases (4/5/6/7): 7.5 storms

COD: 7.5 storms

 

 So, very little correlation of MJO phase and major KATL/KRDU S/IP's since 1974.

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it looks like an average of 1962 and 1967 Don...1967 had more chances but they both had big March events...1967 had much more snow because the Ash Wed. storm just grazed the city...

 

Speaking about March, even as the CFSv2 has recently been suggesting a warm month in the Northeast (cold in the Pacific Northwest), my emerging pool of analogs is more mixed in the East. The idea of cold in parts of the west is well-supported in the early pool. However, in the East, there's less consensus on warmth. The 1976 analog is in the mix and the CFSv2's latest monthly forecast resembles that case. But some better ones including 1952 and 1960 are there, as well. The evolution of ENSO and progression of the MJO will be among the important factors in refining things over the next week or two.

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Don, we here in the West and Central Regions are closely watching the storm potential next week. Additional N Pacific WSR should help provide some clarity and the 12Z Ensembles certainly agree that this will be a time frame to watch for both severe and winter weather across the Southern Rockies/Southern/Central Plains on E into the Mid West near the February 20th, +/- a couple of days.

 

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1215 PM EST WED 13 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
         VALID 14/1100Z TO 15/1100Z FEBRUARY 2013
         WSPOD NUMBER.....12-075

I.  ATLANTIC REQUIREMENTS
    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
    1. FLIGHT ONE -- NOAA 49
       A. P28/ DROP 10 (35.0N 150.0W)/ 15/0000Z
       B  NOAA9 11WSC TRACK28
       C. 14/1930Z
       D. 19 DROPS AS PUBLISHED ON TRACK
       E. 41,000 TO 45,000 FT/ 15/0600Z

    2. SUCCEEDING DAY OUTLOOK:  POSSIBLE
       P21/ DROP 10 (40.0N 135.0W)/ 16/00000Z
    3. REMARK: THE NOAA G-IV WILL FLY TRACK P-9 TODAY AS
       DETAILED IN WSPOD 12-074.
 

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Srain, initially I thought this 21-23rd storm would end up being a SECS, however it seems the storm ahead of it which was supposed to act as a 50/50 is trending weaker, AND, the shortwave associated with the storm is wrapping up too much therefore the heights will be pumped out ahead of it too much. 

 

I do think it will be a nice storm for someone in Midwest though for sure. 

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As mentioned yesterday, a potent Winter Storm is suggested by the medium/long range operational and ensemble guidance for the mid/late next week time frame across the Great Basin spreading ENE into the Central/Southern Plains and then toward the Upper Mid West.  There is agreement that a deep 500mb low and attending surface low will develop with lee side cyclogensis near or just S of Denver setting the stage for a potential severe weather episode across the Central/Southern Plains on E into the Mid/Lower Mississippi Valley Region as a 100kt+ jet streak crosses E Texas. Such a scenario with enough Gulf moisture return with additional energy from a potent sub tropical jet could set the stage for a significant widespread severe weather event and will need to be monitored closely.

 

In the cold sector, heavy snow and near blizzard conditions may be possible NW and N of the surface low across the Rockies, portions of the Central/Northern Plains into the Great Lakes Region depending on the eventual storm track. The favored track at this time appears to be from Colorado ENE to near Cincinnati, but a bit further S track cannot be ruled out at this time. A NOAA G-IV has been sampling the N Pacific the past couple of days and another additional flight is scheduled departing from Hawaii this evening.

 

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0550 PM EST WED 13 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
         VALID 14/1100Z TO 15/1100Z FEBRUARY 2013
         WSPOD NUMBER.....12-075 AMENDMENT

I.  ATLANTIC REQUIREMENTS
    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
    1. FLIGHT ONE -- NOAA 49 CHANGED DESTINATION
       A. P28/ DROP 10 (35.0N 150.0W)/ 15/0000Z
       B  NOAA9 11WSC TRACK28M
       C. 14/1930Z
       D. 12 DROPS AS PUBLISHED ON TRACK THROUGH DROP 10
          AND THEN DROPS AT 32.5N AND 30.0N ENROUTE PHNL
       E. 41,000 TO 45,000 FT/ 15/0600Z

    2. SUCCEEDING DAY OUTLOOK:  CHANGED
       P54/ DROP 8 (45.0N 166.0W)/ 16/00000Z
    3. REMARK: THE NOAA G-IV WILL FLY TRACK P-9 TODAY AS
       DETAILED IN WSPOD 12-074.
 

 

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That really will only matter north of NYC. From 40N south, we'll be under the influence of the SE ridge.

Looks like it will be a Davis straits-west -NAO... Pacific looks bad, thanks to the MJO. I'd say the East coast will avoid a torch thanks to the NAO late month, early March, which will help squash the SE ridge some. The N Plains look very cold, with the west below average and the rest of the country near average to slightly below average (days 8-20). 

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Looks like it will be a Davis straits-west -NAO... Pacific looks bad, thanks to the MJO. I'd say the East coast will avoid a torch thanks to the NAO late month, early March, which will help squash the SE ridge some. The N Plains look very cold, with the west below average and the rest of the country near average to slightly below average (days 8-20). 

 

I am clearly in the minority, so what I am missing that everyone has locked in the -NAO for so long? I'm just not seeing it, but you, HM, and some energy mets I talk to are all on board with it (I can see a -NAO through like Feb 25 or so, but I'd think it should relax toward neutral after that).

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