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Stormlover74

January 2021 General Discussions & Observations Thread

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35 minutes ago, eduggs said:

Thanks. That's helpful to visualize the relative likelihoods and typical ranges of each state during this upcoming time of year. It's hard to tell, but it looks like AO-/PNA+ is most common.

For another look, below is the percentage of days for select AO/PNA states and the percentage of days with 4" or greater snowfalls for New York City during the January 20-31, 1950-2020 period for each of those states:

AO-/PNA+: 39% days, 67% of daily 4" or greater snowfalls
AO-/PNA-: 19% days, 5% of daily 4" or greater snowfalls
AO+/PNA+: 20% days, 24% of daily 4" or greater snowfalls
AO+/PNA-: 22% days, 5% of daily 4" or greater snowfalls

 

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1 hour ago, NEG NAO said:

12Z Euro looks like Canadian - a miss  south mostly

prateptype_cat_ecmwf.conus.pngprateptype_cat_ecmwf.conus.png

 

 

Here's the 24 hour difference in runs out west as our storm organizes.  The new run had less phasing out west and buried the s/w.  A piece broke off and ended up to our south under the block.  

 

 

1bbfe208-5c3e-465f-9c44-ba8398c995dd.gif

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Today was partly sunny and breezy. Temperatures generally topped out in the lower and middle 40s across the region. Tomorrow will be a similar day.

During the second half of January, there will be some potential for snow events in the Middle Atlantic and southern New England regions, even as the forecast AO-/PNA- pattern is typically not a very snowy one. There continues to be ensemble support for a possible light snow event in the region during the January 21-23 timeframe during the passage of a strong cold front. Another timeframe highlighted by the ensembles is January 25-28. The latter period may have greater potential. However, neither period is likely to produce a significant snowfall (6" or above) for the Washington, DC to Boston corridor.

AO-/PNA- patterns are typically not snowy. The frequency of measurable snowfall is just over 90% of climatology in Boston and Philadelphia and around 80% of climatology in New York City for the January 21-31, 1950-2020 period. The frequency of 2" or more daily snowfall was just above 90% of climatology for Philadelphia, but fell sharply to 50% of climatology in New York City and 65% of climatology in Boston. For daily snowfall amounts in excess of 2", the frequency fell sharply for Philadelphia. As a result, such patterns typically have produced significant snowstorms (6" or above snowfall) in the northern Middle Atlantic and southern New England regions during late January. The biggest snowfalls during an AO-/PNA- pattern during the January 20-31, 1950-2020 period were as follows: Boston: 7.3", January 21, 2011; New York City: 4.2", January 21, 2011; and, Philadelphia: 3.0", January 20, 2000.

Afterward, the evolution of the AO will determine whether potential for measurable snow events will continue into February.

The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -1.1°C for the week centered around January 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.07°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +20.69 today.

Today, the preliminary Arctic Oscillation (AO) figure was -1.579.

On January 16 the MJO was in Phase 4 at an amplitude of 1.143 (RMM). The January 15-adjusted amplitude was 1.148.

Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America.

The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish.

Based on sensitivity analysis applied to the latest guidance, there is an implied 83% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.2°.

 

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18Z GFS (an untrustworthy run usually---is our salvation?) for the last week of the month is again  averaging 33degs. (28/38).        Barely normal when a day ago it was 12 degrees less and more fitting of a PV breakup.        We would finish January w/o getting below 20.      Snow on the 26th. is virtually gone too.

Roy Orbison is readying himself to sing    "It's Over"-----but I won't give the link yet.    lol         Seems I use this song too often.

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10 minutes ago, MJO812 said:

FB_IMG_1610939556950.jpg

we are still slightly above normal in the metro so far only need a few inches the rest of the month to stay above normal for the season - also note the lack of lake effect snow this year caused by the lack of any real arctic air so far. Also below normal so far in parts of the Ohio Valley .

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10 minutes ago, MJO812 said:

FB_IMG_1610939556950.jpg

That Bridgeport yearly average to day is false as Bridgeport is notorious for under reporting through history.

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Good morning all,  My take based on the 00z/06z ops and 00z/18 ensembles.  00z/18 NAEFS helped guide the wintry and qpf call (~0.4" w-e  I80 axis)

The I84 corridor has basically scattered dustings this afternoon and evening, Tuesday afternoon-Wednesday afternoon, and again Thursday-Friday. Amounts in the Poconos might add up to 1 or 2 inches by Friday, trace to 1/2 inch elsewhere by Friday eve. Basically just be alert for quick changes but overall no big deal. 
 
Travelers into the northeast USA Monday-Tuesday the 25th-26th should be aware that an extensive light to moderate hazardous wintry episode is expected for all untreated surfaces, especially the I84 corridor. It may even briefly begin as snow-ice down to Philly Monday. The front end Monday start time is uncertain..it could start for a couple of hours Monday morning then stop for 12 hours. The bulk of this event probably occurs late Monday night into Tuesday night the 26th. Odds favor a change to rain south of I80 by Tuesday morning the 26th, but ice or snow north of I80, especially the I84 corridor.   NYC-LI--- have no confidence on sleet-snow start or just rain...close but for now both are options, from a multiple model blend. Right now, I think most of the wintry is to the nw-ne of NYC, though a start as wintry is possible.  I'll probably start a thread on this, this afternoon pending receipt of the entire slate of guidance.  I do see the para is south and that the EPS ensembles are south.  I just think there is enough ensemble data for an event of sorts. Will check back mid afternoon.

 

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The next 8 days are averaging 35degs.(30/39).          Making it 30degs., or -2.0.

TOTAL MODEL FAIL.      COLD IS GONE FOR JANUARY  and   FEBRUARY STARTS ALL IN THE 50'S.      Must be the lack of upper air data over the Pacific due to Covid commercial airline flight cancellations.       I love making excuses.

CMC still the coldest, and with some snow still showing near the 26th.

Oooh!,  I almost forgot:

40*(65%RH) here at 6am.      39* at 7am.          45* by Noon.        47* by 3pm.         39* by 10pm.

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2 hours ago, tmagan said:

If winter ended today, Central Park would tie for the tenth warmest winter ever.

Another winter with very little cold air anywhere in the country so far

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2 hours ago, tmagan said:

If winter ended today, Central Park would tie for the tenth warmest winter ever.

Is that notable in 2020? Perhaps for a cool year? Almost every month we have is at or above normal these days.

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Morning thoughts...

Today will be partly to mostly sunny. Temperatures will likely reach the lower and middle 40s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 45°

Newark: 47°

Philadelphia: 47°

A strong cold front could move across the region late in the week bringing a period of light snow or flurries.

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1 hour ago, bluewave said:

The EPS is weaker with the -EPO and stronger with the -PNA for January 26th than a few days ago. So a system that is too amped will be too warm like some of the 0z OP models were showing. A weaker system like the models had yesterday was getting forced to the south. So we may need a perfect thread the needle track to get snow out of this one.

New run

CDE5D7C8-E1BC-42C3-AF3E-CDEE6F9ED633.thumb.png.f34ee571da691afe865bdf6cd1cc8a4c.png
Old run

C29D9306-34F2-4DC4-ABE4-FBFF9E74C89E.thumb.png.01b1d6534af4002e2c2c5bddb606b159.png


19BED94A-C2D5-4CA4-BF59-87F251E556A5.thumb.jpeg.7443a24912d831ac676bae2893319e7a.jpeg

Yet another -EPO fail incoming and yea, the -PNA is getting stronger as we move forward in time

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3 hours ago, wdrag said:

Good morning all,  My take based on the 00z/06z ops and 00z/18 ensembles.  00z/18 NAEFS helped guide the wintry and qpf call (~0.4" w-e  I80 axis)

The I84 corridor has basically scattered dustings this afternoon and evening, Tuesday afternoon-Wednesday afternoon, and again Thursday-Friday. Amounts in the Poconos might add up to 1 or 2 inches by Friday, trace to 1/2 inch elsewhere by Friday eve. Basically just be alert for quick changes but overall no big deal. 
 
Travelers into the northeast USA Monday-Tuesday the 25th-26th should be aware that an extensive light to moderate hazardous wintry episode is expected for all untreated surfaces, especially the I84 corridor. It may even briefly begin as snow-ice down to Philly Monday. The front end Monday start time is uncertain..it could start for a couple of hours Monday morning then stop for 12 hours. The bulk of this event probably occurs late Monday night into Tuesday night the 26th. Odds favor a change to rain south of I80 by Tuesday morning the 26th, but ice or snow north of I80, especially the I84 corridor.   NYC-LI--- have no confidence on sleet-snow start or just rain...close but for now both are options, from a multiple model blend. Right now, I think most of the wintry is to the nw-ne of NYC, though a start as wintry is possible.  I'll probably start a thread on this, this afternoon pending receipt of the entire slate of guidance.  I do see the para is south and that the EPS ensembles are south.  I just think there is enough ensemble data for an event of sorts. Will check back mid afternoon.

 

The models are all over the place with next weeks event - was surprised that the EURO went from a miss to the south at 12Z yesterday - to last nights 0Z lakes cutter agreeing with many other models that the block is basically a non factor with no redevelopment south of us along the coast.And then the EURO ensembles are south ?? Also the timing start is questionable - is that 12 pause in the event even real on the surface maps of some models ? Along with the early Monday morning start time ? Too many questions here and not enough answers yet IMO. Won't even get into precip type issues as the track of the storm being a major question mark at this time will basically decide the main precip type in any given location around the metro. I think just a general winter storm thread covering the 25th thru 27th with a details to follow description headline is an idea IMO - also there will be several adjustments in the details as the week wears on IMO....

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6 minutes ago, bluewave said:

With such a limited amount of cold air, we end up relying on thread the needle solutions for snow. Too weak a storm it gets suppressed and too strong it’s warm. Challenging pattern this winter with blocking too far south and models underestimating the Pacific Jet. 

691E840A-214C-48D1-94B4-06559B515BFF.thumb.png.bdcc4d4baafc5c2a87b776c7839f870b.png

5FD24690-40D3-41A8-B35E-97A96F6B2F84.thumb.png.ecda1512e75086ac0442ac5f1e90ef5e.png


 

 

The models have consistently been way too cold in the long range since November. Too aggressive with fantasy -EPO’s and to a lesser extent +PNA’s. A function, I believe like you said, of underestimating the PAC jet. The end of this month is getting warmer by the day with each model run, now they are playing catch-up as we get closer because they were way too cold at range 

 

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2 hours ago, Brian5671 said:

Another winter with very little cold air anywhere in the country so far

SSW fail like it always does

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36 minutes ago, MJO812 said:

 

Yep, February is in trouble, big trouble. Both -NAO/-AO showing signs of breaking down in the beginning of February, couple that with MJO phase 6/-GLAAM and you have a torch-a-rama in the east. If anyone was wondering where the canonical La Niña pattern has been, here it comes.....

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well if it's not going to snow give me warmth.   40 and partly cloudy every day is worthless

on the plus side the warm winter nationwide is helping with the pandemic-less disruption due to snow/cold, people can get outside, mass testing/vaxx sites can be set up easier etc etc.   A 13-14 type winter this year would have been brutal in that regard.

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15 minutes ago, MJO812 said:

SSW fail like it always does

not sure why everyone gets excited for these-once in awhile it benefits us-but it's mostly a benefit for the other side of the globe....

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4 minutes ago, Brian5671 said:

not sure why everyone gets excited for these-once in awhile it benefits us-but it's mostly a benefit for the other side of the globe....

The information on social media concerning such events is typically quite poor. Although a lot is still not well understood, there is a large body of evidence that displacement events typically favor North America for cold while vortex-splitting events typically favor Eurasia with the cold. This SSW fell into the latter category. Parts of Asia and Europe have seen some severe cold. Much of North America hasn’t.

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In December New York City received 10.5” snow. In January, just a trace of snow has fallen. The lowest January snowfall figures following a December with 10.0” or more snow were 0.1” during winter 1933-34 and 0.3” during winter 1912-13.

In addition, there have been 10 cases where January received less than 6.0” snow following a December with 10.0” or more snow. In 40% of cases, the remainder of winter saw less than 10.0” snow. In 50% of cases, the remainder of the snow season saw 20.0” or more snow. In all cases during which the remainder of winter picked up more than 10.0” snow, February saw 10.0” or more snow.

 

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12Z GFS Continued you would think at this point with the LP encountering resistance from the blocking it would redevelop off the coast

gfs_mslp_pcpn_frzn_us_32.png

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