zwyts 8th consecutive winter outlook for DCA - 2011-12

[Deck Pic]

1981-2010 Norms

DEC: Normal to +1

JAN: -1 to -2

FEB: +1 to +2

Overall: Lean slightly above normal

Snow at DCA: 12"

Analogs: 1934, 1943, 1956, 2008

Past Outlooks:

2010-11

December: -1 (-4.9)

January: +3 to +5 (-1.2)

February: normal to +1 (+3.7)

Overall DJF: +1 to +2 (-0.8)

Snow for whole season:

DCA: 14"-16" (10.1")

2009-10

December: +2 to +3 (-1.6)

January: Normal to +1 (+0.5)

February: Normal (-3.9)

DJF Anomaly: +1 (-1.7)

DCA Seasonal Snowfall for OCT-APR: 15" (56.1")

2008-09

Overall DJF: +0.3 (-0.2)

December: -3 (+0.8)

January: +2 (-3.2)

February: +2 (+1.7)

DCA Snow: 17" (7.5")

2007-08

TEMPERATURES at DCA (ACTUAL)

Overall DJF: +1.7 (+3.4)

DEC: -1 (+2.3)

JAN: +3 (+5.1)

FEB: +3 (+2.9)

SNOWFALL AT DCA: 11-13" (4.9")

2006-07

Overall Temps: DJF: -0.8 (Actual: +1.1)

Monthly Breakdowns for DCA

December: Normal(Actual: +4.7)

January: -2 to -3(Actual: +5.8)

February: Normal: (Actual: -7.2)

Official Snowfall at DCA: 15-20"(Actual: 9.5")

2005-06

Overall: DJF: -0.5 (Actual: +1.9)

December: -1 to -2(Actual: -3.1)

January: +2(Actual: +8.1)

February: -2(Actual: +0.5)

Snow for DCA only: 16"(Actual: 13.6")

2004-05

Overall DJF: +1.0 (Actual: +1.0)

December: +1.5 to +2.5(Actual: +0.5)

January: +1 to +2(Actual: +1.1)

February: Normal to -1(Actual: +1.5)

Snow for DCA and Vicinity: 18" to 25"(Actual: 12" to 16" with 12.5" official at DCA)

[Analog96]

1981-2010 Norms

DEC: Normal to +1

JAN: -1 to -2

FEB: +1 to +2

Overall: Lean slightly above normal

Snow at DCA: 12"

Analogs: 1934, 1943, 1956, 2008

Past Outlooks:

2010-11

December: -1 (-4.9)

January: +3 to +5 (-1.2)

February: normal to +1 (+3.7)

Overall DJF: +1 to +2 (-0.8)

Snow for whole season:

DCA: 14"-16" (10.1")

2009-10

December: +2 to +3 (-1.6)

January: Normal to +1 (+0.5)

February: Normal (-3.9)

DJF Anomaly: +1 (-1.7)

DCA Seasonal Snowfall for OCT-APR: 15" (56.1")

2008-09

Overall DJF: +0.3 (-0.2)

December: -3 (+0.8)

January: +2 (-3.2)

February: +2 (+1.7)

DCA Snow: 17" (7.5")

2007-08

TEMPERATURES at DCA (ACTUAL)

Overall DJF: +1.7 (+3.4)

DEC: -1 (+2.3)

JAN: +3 (+5.1)

FEB: +3 (+2.9)

SNOWFALL AT DCA: 11-13" (4.9")

2006-07

Overall Temps: DJF: -0.8 (Actual: +1.1)

Monthly Breakdowns for DCA

December: Normal(Actual: +4.7)

January: -2 to -3(Actual: +5.8)

February: Normal: (Actual: -7.2)

Official Snowfall at DCA: 15-20"(Actual: 9.5")

2005-06

Overall: DJF: -0.5 (Actual: +1.9)

December: -1 to -2(Actual: -3.1)

January: +2(Actual: +8.1)

February: -2(Actual: +0.5)

Snow for DCA only: 16"(Actual: 13.6")

2004-05

Overall DJF: +1.0 (Actual: +1.0)

December: +1.5 to +2.5(Actual: +0.5)

January: +1 to +2(Actual: +1.1)

February: Normal to -1(Actual: +1.5)

Snow for DCA and Vicinity: 18" to 25"(Actual: 12" to 16" with 12.5" official at DCA)

Are your analogs fall or winter analogs? For example, is "1934" 1933-34, or 1934-35?

[Ian]

1934

[Deck Pic]

Are your analogs fall or winter analogs? For example, is "1934" 1933-34, or 1934-35?

latter

[Ji]

Why did you only call for 15 in 2009-2010? During a nino?

[Deck Pic]

1934

we don't have reliable data, but that was probably a neutral winter or very weak nina, but it did follow a cold period....This winter, ENSO will be more of a factor I think....Do you know anthing about the January 22, 1935 system?.....It probably had a nice southern stream...I think there was a decent period around that date, no?

[Ji]

Wake me up when we have a southern stream...the miller a forecasted by the euro in December always ends up a miller b

[Deck Pic]

Why did you only call for 15 in 2009-2010? During a nino?

I fixed it for CWG and we did well....I released it too early and I picked some warm analogs...I actually put a fair amount of time into that one...BUST

here was the write up

http://fortysouthwx.com/index.php?/topic/49-zwyts-2009-10-dca-winter-outlook/page__p__363__hl__outlook__fromsearch__1#entry363

[Ji]

You had the right play call but lack of execution. You were right about many things

[Deck Pic]

You had the right play call but lack of execution. You were right about many things

the CWG outlook a month or 2 later was much better..it became apparent that we would have a big winter.....though several went for a big winter early, I missed it

[Ian]

we don't have reliable data, but that was probably a neutral winter or very weak nina, but it did follow a cold period....This winter, ENSO will be more of a factor I think....Do you know anthing about the January 22, 1935 system?.....It probably had a nice southern stream...I think there was a decent period around that date, no?

DC got 23.4" from the 16th to the 26th. That was pretty much the winter outside some piddly events. Re-analysis shows some southern stream or pseudo southern stream (seems to have maybe broken off the northern stream at some point). Maybe a thread the needle situation with the big event (11" on 23, .3 on 24). Also had a 6.1 and a 4.5 (probably snow to rain looking at qpf) right before it.

As I noted before I've pinged the 1930s (particularly early) in various climo looks over the last few months. Then there was the similarity between the rain events and 1934 (seemingly). http://www.americanw...e-aug-sep-2011/

[usedtobe]

Matt, I like your snowfall totals and think your temps are Ok though I'd probably go right around average as I'm worried about the NAO. .I have no idea about the monthly break down. My guess for snow right now is 12-16 for dca. Pretty much around normal. My guess is pretty wimpy as I think there is more uncertainty this year than most.

[Deck Pic]

DC got 23.4" from the 16th to the 26th. That was pretty much the winter outside some piddly events. Re-analysis shows some southern stream or pseudo southern stream (seems to have maybe broken off the northern stream at some point). Maybe a thread the needle situation with the big event (11" on 23, .3 on 24). Also had a 6.1 and a 4.5 (probably snow to rain looking at qpf) right before it.

As I noted before I've pinged the 1930s (particularly early) in various climo looks over the last few months. Then there was the similarity between the rain events and 1934 (seemingly). http://www.americanw...e-aug-sep-2011/

thanks...It might be in the KU book....will have to check

[Ian]

thanks...It might be in the KU book....will have to check

It looks like we got kinda lucky

[Deck Pic]

Matt, I like your snowfall totals and think your temps are Ok though I'd probably go right around average as I'm worried about the NAO. .I have no idea about the monthly break down. My guess for snow right now is 12-16 for dca. Pretty much around normal. My guess is pretty wimpy as I think there is more uncertainty this year than most.

thanks...I think my temps average to +0.2 so right at normal...I too am worried that I am too warm, especially with the new norms skewing Jan and Feb a degree warmer....I curved temps a bit cooler at the end based on the NAO, but maybe I didn't go cold enough......

[Deck Pic]

It looks like we got kinda lucky

why?...there is a -NAO and a big ULL over Dixie?...I guess my point is we are less likely to see that this winter with ENSO probably more of a factor....that was part of the reason I didn't go bigger snow....I haven't really worked on CWG yet...that isn't for another month...things could change

[Deck Pic]

It looks like we got kinda lucky

no...it was a high impact event for the entire east coast.....blizzard for many places..snow into the deep south...crippling for much of I-95.....it is probably in the KU book...I think I misplaced mine

[Ian]

why?...there is a -NAO and a big ULL over Dixie?...I guess my point is we are less likely to see that this winter with ENSO probably more of a factor....that was part of the reason I didn't go bigger snow....I haven't really worked on CWG yet...that isn't for another month...things could change

it reminds me a bit of the psuhoffman storm though more potent at least at dc. that was not necessarily a done deal unless it moved by perfectly and developed perfectly which it did. blocking is there but not our best setup IMO. by that panel it's pretty evident it would snow but in the days prior not as much.

[Ian]

no...it was a high impact event for the entire east coast.....blizzard for many places..snow into the deep south...crippling for much of I-95.....it is probably in the KU book...I think I misplaced mine

that doesnt mean we didnt get lucky.

[Ian]

From KU "Another widespread snowstorm battered the entire region from Washington to Boston on 22-24 January 1935, leaving 12-18 in. (30-45 cm) of snow in the cities and over 20 in. (50cm) in Maine. This storm system was slow to develop as a complex series of low pressure systems consolidated along a frontal boundary across the southeastern United States on 21-22 January, with snow spreading from the Gulf Coast to the middle Atlantic states. Snowfall rates intensified on 23 January as a low pressure consolidated off the Carolinas coastline and moved northeastward over the next 24 hours."

[WVclimo]

With the exception of that period in January 1935, those years were really lousy for snowfall in this area. The other three seasons combined averaged less than 50% of normal, and even including 1934-35 still brings the average of the four analogs to less than 65% of normal.

I don't expect to reach average snowfall this year anyway, so not too disappointed by this outlook. Good luck with your forecast, Z.

[Deck Pic]

that doesnt mean we didnt get lucky.

there is always luck involved...looks like a good pattern for a storm to me though

[Ian]

there is always luck involved...looks like a good pattern for a storm to me though

im not sure we're even discussing the same thing entirely. i liked 1934 prior to your outlook because it had a lot of snow comparatively. i have the maps going back days prior but didnt feel like making a loop etc. the evolution is not one i would bank on at range from having much chance compared to a nino pattern or something. as far as i can tell the sw came out of sw canada/pac nw. i just don't feel like that's something we usually do well with.

on a side note: why not consider last year an analog given the nao state etc? it has to be a second yr event? my issue with understanding long range forecasting might partly be why people end up with so few analogs. i mean, i get why.. but it;'s not a lot of data.

[Deck Pic]

im not sure we're even discussing the same thing entirely. i liked 1934 prior to your outlook because it had a lot of snow comparatively. i have the maps going back days prior but didnt feel like making a loop etc. the evolution is not one i would bank on at range from having much chance compared to a nino pattern or something. as far as i can tell the sw came out of sw canada/pac nw. i just don't feel like that's something we usually do well with.

on a side note: why not consider last year an analog given the nao state etc? it has to be a second yr event? my issue with understanding long range forecasting might partly be why people end up with so few analogs. i mean, i get why.. but it;'s not a lot of data.

hard to tell from one mean map, but yes...doesn't look like a split flow so perhaps not an active STJ.....I think the weaker the nina, the better chance of having a more active/robust STJ...that was my main point.....

last year was a fairly strong Nina coming on the heels of a Nino....it doesn't HAVE to be a 2nd year event, but i think most would dismiss last year as an analog because the evolution of the PAC is so different and some of these longwave patterns and tendencies lag behind by months and even longer....we can have hangover/persistence patterns for over a year sometimes until something dislodges it....so personally I threw out last year right away, but that isn't to say there won't be similarities....I think analogs are good for some broad guidance on temps/snow....I don't weigh them too much

[ORH_wxman]

hard to tell from one mean map, but yes...doesn't look like a split flow so perhaps not an active STJ.....I think the weaker the nina, the better chance of having a more active/robust STJ...that was my main point.....

It could have been the polar jet splitting. Jan 1996 was not a STJ event...it was the polar jet splitting and the dominant s/w ended up in the southern branch. Perhaps this one was similar.

[RIC Airport]

Just taking a look at the data for RIC, late January 1935 had a rather impressive streak of very cold temperatures with many days featuring single digit lows. There was even a low temperature of -4F on 1/28/35. As Ian mentioned, looks like this period was the highlight of that winter. That two week stretch did feature several minor snowfalls (1-2") with the biggest being a 4 inch event on 1/26/35. There was also a 3" event on 12/10-11/1934.

[RIC Airport]

Just taking a look at the data for RIC, late January 1935 had a rather impressive streak of very cold temperatures with many days featuring single digit lows. There was even a low temperature of -4F on 1/28/35. As Ian mentioned, looks like this period was the highlight of that winter. That two week stretch did feature several minor snowfalls (1-2") with the biggest being a 4 inch event on 1/26/35. There was also a 3" event on 12/10-11/1934.

1/22-23/1935 must've been quite an ice event. High of 33F and low of 25F with 2.51" of precip on the 23rd. The high on the 22nd was 61F

[H2O]

Not that I have any skill in this whatsoever but if I were to Ruggie things from some of the other pieces i have read here and there my guess is a flip from your temps call

DEC: Norm to -0.5

JAN: Norm

FEB: -1

I don't really have an explanation for why I think this and defer to your abilities moreso than mine. Call it a gut feeling. No snow call from me as like you said I think if we can't get much help from the STJ then I can see a below avg. snow total.

[Ji]

we might as well be in Richmond. Look at the stats. We suck

[Deck Pic]

Not that I have any skill in this whatsoever but if I were to Ruggie things from some of the other pieces i have read here and there my guess is a flip from  your temps callDEC: Norm to -0.5JAN: Norm FEB: -1 I don't really have an explanation for why I think this and defer to your abilities moreso than mine.  Call it a gut feeling. No snow call from me as like you said I think if we can't get much help from the STJ then I can see a below avg. snow total.

We actually live in a hard place to predict temp anomalies. We are in a geographic location that is often caught between 2 regimes. Quite often we are not geographically far from reverse anomalies. It is even harder when you use a multiple-year sample to get an idea. So for example a month like February if we lived in Dixie it would be a no brainer to go heavy plus values, but where we live it honestly doesn't take a huge pattern difference to go from +2 to -2.