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January 2020 General Discussions & Observations Thread


Rtd208
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12 minutes ago, snowman19 said:

I think if there is to be a change it’s post 2/15, more like late/end of February. Vortex over AK setups just don’t flip overnight, they always stay longer than expected, then you have to seed Canada with cold again and scour out the PAC maritime air....that’s takes some time. Come March, with the wavelength change, IO forcing is actually cold, not warm anymore, so if we have IO forcing at that point, I’d expect a cold March, yet again

Yeah the vortex is going to weaken eventually. I think more towards the end of February as well. I believe @Isotherm thinks the same. 
 

Im more interested if the cold shot around the 5th gets punted. The weeklies and eps have been consistent in showing this.

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14 minutes ago, snowman19 said:

I think if there is to be a change it’s post 2/15, more like late/end of February. Vortex over AK setups just don’t flip overnight, they always stay longer than expected, then you have to seed Canada with cold again and scour out the PAC maritime air....that’s takes some time. Come March, with the wavelength change, IO forcing is actually cold, not warm anymore, so if we have IO forcing at that point, I’d expect a cold March, yet again

It’s fairly rare to see the AK vortex setup in mid or late winter though.  That is more commonly a feature that comes in November or December and then never leaves.   They tend to be more transient when they develop later 

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13 minutes ago, Allsnow said:

Yeah the vortex is going to weaken eventually. I think more towards the end of February as well. I believe @Isotherm thinks the same. 
 

Im more interested if the cold shot around the 5th gets punted. The weeklies and eps have been consistent in showing this.

 

There`s a piece day 8 -10 coming into the flow.

We would really benefit for some more wave spacing between the day 8 and day 9 EC systems. We need that to delay about 24 hours to even have a shot because this comes rolling in for 2/3 days. 

ecmwf-deterministic-namer-t850-0558400 jan 22  day 10 trough.png

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24 minutes ago, Allsnow said:

Yeah the vortex is going to weaken eventually. I think more towards the end of February as well. I believe @Isotherm thinks the same. 
 

Im more interested if the cold shot around the 5th gets punted. The weeklies and eps have been consistent in showing this.

Yeah, we may end up needing help from MJO or other factors to get that vortex out of Alaska. This is our first time since the 2006-2012 era that we had such a strong +EPO from December into at last the start of February. The chart below shows how different this is from what we have experienced since 2012. The CPC chart is the inverse of how we typically discuss the EPO. The negative values are what we consider the +EPO. The positive values since 2013 reflect the predominant -EPO over this period.

https://www.cpc.ncep.noaa.gov/data/teledoc/ep_ts.shtml

AE10BCCF-8CBF-4A20-8C5C-11BFF5E61150.gif.9a7d45a0dd959b2c7afe1fa01732f9fa.gif

 

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3 minutes ago, bluewave said:

Yeah, we may end up needing help from MJO or other factors to get that vortex out of Alaska. This is our first time since the 2006-2012 era that we had such a strong +EPO from December into at last the start of February. The chart below shows how different this is from what we have experienced since 2012. The CPC chart is the inverse of how we typically discuss the EPO. The negative values are what we consider the +EPO. The positive values since 2013 reflect the predominant -EPO over this period.

https://www.cpc.ncep.noaa.gov/data/teledoc/ep_ts.shtml

AE10BCCF-8CBF-4A20-8C5C-11BFF5E61150.gif.9a7d45a0dd959b2c7afe1fa01732f9fa.gif

 

Agreed. I just don’t think that vortex simply goes away overnight. It’s almost always a process. If a real change is to actually come, I think it’s the end of February or even the beginning of March

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36 minutes ago, Allsnow said:

Yeah the vortex is going to weaken eventually. I think more towards the end of February as well. I believe @Isotherm thinks the same. 
 

Im more interested if the cold shot around the 5th gets punted. The weeklies and eps have been consistent in showing this.

 

ecmwf-ensemble-avg-nhemi-z500_anom-0947200 JAN 22 DAY 15 BOMB.png

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1 hour ago, PB-99 said:

 

There`s a piece day 8 -10 coming into the flow.

We would really benefit for some more wave spacing between the day 8 and day 9 EC systems. We need that to delay about 24 hours to even have a shot because this comes rolling in for 2/3 days. 

ecmwf-deterministic-namer-t850-0558400 jan 22  day 10 trough.png

Yes, but it originates from the pac as the vortex is wound tight with all the cold. Nice pna spike but a crap airmass. The eps has less then a inch for that timeframe 

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16 minutes ago, Allsnow said:

Yes, but it originates from the pac as the vortex is wound tight with all the cold. Nice pna spike but a crap airmass. The eps has less then a inch for that timeframe 

 

The real departures in the period are a result of higher night time low temps.

It`s a week of 40 - 42 with low temps in the low 30`s at night and not the normal mid 20`s. The day time temps on the EPS are not warm tho.

Just warm enough because it`s PAC air and it modifies quickly under what looks like a deep trough.  

 

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34 minutes ago, Allsnow said:

Yes, but it originates from the pac as the vortex is wound tight with all the cold. Nice pna spike but a crap airmass. The eps has less then a inch for that timeframe 

This! It’s what some people don’t understand, all the +PNA is doing is trapping PAC air, even if a -NAO block were to form, it would just trap the crap PAC air coming in from the west at that time under the block. It’s a putrid maritime airmass

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For early February reference, below are the 500 mb height anomalies for snowstorms that brought 6" or more snow to Boston, New York City, and Philadelphia (all 3 locations) during the February 1-15, 1950-2019 period. Storms that commenced prior to February 1 or continued after February 15 are excluded.

One typically found a Greenland-Hudson Bay block and/or a PNA+ ridge coupled with a trough in the East. The variation on a case-by-case basis should also be noted.

Feb-Snow2020.png

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After a cold start, especially outside the City where temperatures fell into the teens with some single digits (Danbury reported a 6° low and Poughkeespie had a minimum temperature of 7°), temperatures rose into the upper 30s in the region.

Temperatures will likely run above normal through the remainder of January. However, a mild finish to a very warm January does not mean that February will likely be warmer than normal. The coefficient of determination for New York City between the January and February temperatures is just 0.07. Records go back to 1869.

Colder air could return during or just after the first week in February.

As long as the Arctic Oscillation remains strongly positive, the risk of widespread significant snow (6" or greater) from Washington, DC to Boston remains low. Since 1950, there were 11 storms that brought 6" or more snow to 2 or more of the following cities: Boston, New York City, Philadelphia, and Washington, DC. Just 1 such storm occurred when the AO was +1.000 or above. Therefore, through most of the remainder of January, the greatest risk of moderate or significant snowfall will likely exist for central and upstate New York and central and northern New England. The pattern could begin to grow more favorable for snow on the coastal plain during the beginning of February should the Arctic Oscillation (AO) fall toward neutral levels.

Before then, a storm could bring 0.50" to 1.50" precipitation, mostly or all rain, to Washington, DC to Boston this weekend. A moderate snowfall with some locally significant amounts could occur across central and upstate New York, central and northern New England, and parts of southern Ontario.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.4°C for the week centered around January 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.52°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions.

For February 1981-2019, the following monthly temperature averages were recorded for cases when the ENSO Region 3.4 anomaly averaged 0.00°C to +0.75°C:

ENSO R1+2 Anomaly < 0: AO+: NYC: 36.9°; Philadelphia: 37.6° (n=101 dates)
ENSO R1+2 Anomaly < 0: AO-: NYC: 34.7°; Philadelphia: 34.9° (n=97 dates)

ENSO R1+2 Anomaly > 0: AO+: NYC: 35.7°; Philadelphia: 36.6° (n=82 dates)
ENSO R1+2 Anomaly > 0: AO-: NYC: 30.9°; Philadelphia: 31.6° (n=58 dates)

February 1981-2019: NYC: 35.8°; Philadelphia: 36.0°

The SOI was -6.17 today.

Today, the preliminary Arctic Oscillation (AO) figure was +1.544.

No significant stratospheric warming event appears likely through January 30. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS. 

On January 21, the MJO was in Phase 7 at an amplitude of 2.044 (RMM). The January 20-adjusted amplitude was 2.153.

The MJO had recently spent 9 consecutive days at an amplitude of 3.000 or above. There have been only 8 cases where the MJO had an amplitude of 3.000 or above for 7 or more consecutive days. The shortest period from the start of that stretch that saw the MJO's amplitude fall below 1.000 was 20 days. The mean period was 36 days. The longest period was 55 days. Based on this historic experience, the MJO likely won't reach low amplitude until near or after the end of January.

Since 1974, there were 8 prior cases where the MJO reached Phase 4 at an amplitude of 1.500 or above in the January 5-20 period. In 7 or 88% of those cases, the MJO progressed into Phases 7 and 8. The MJO moved into Phase 7 on January 20.

Based on sensitivity analysis applied to the latest guidance, New York City has an implied near 100% probability of a warmer than normal January. The monthly mean temperature could finish near 39.0° in New York City.

The probability that January 2020 will finish with among the 10 highest January average temperatures on record has increased to just over 60%. The 10th warmest January occurred in 1906 with a monthly mean temperature of 38.4°. The 9th warmest January was January 1949 with an average temperature of 38.6°.

 

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4 hours ago, snowman19 said:

This! It’s what some people don’t understand, all the +PNA is doing is trapping PAC air, even if a -NAO block were to form, it would just trap the crap PAC air coming in from the west at that time under the block. It’s a putrid maritime airmass

Marginal air could work though this time of year, it worked in 2006. You just need to get very lucky with everything else.

The +PNA is definitely a plus. We're also finally seeing the Nino response which works out well in February so not all is lost.

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11 minutes ago, SnoSki14 said:

Marginal air could work though this time of year, it worked in 2006. You just need to get very lucky with everything else.

The +PNA is definitely a plus. 

An intensifying low track to the BM can do wonders even in a subpar pattern this time of year. Just ask the 240 hr GFS,

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Next 8 days are averaging 40.5degs., or 8degs. AN.

Month to date is  +6.5[38.9].         Should be about +6.9[39.3] by the 31st.

The first week of February looks much colder now at just +2.0[35.0]---but the price of that is that the GFS*** has no Snow for its entire duration.     EURO likes the end of the month/Feb 01 with 4", CMC is a Trace.     ***Latest run, 12Z, back to +7.0[40.0].

33* at 6am.       36* by 9am.      41* by Noon.      46* by 3pm.

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4 hours ago, RDRY said:

Ah, the EURO with the next tracking debacle to appropriately close this fine month. Two days to meltdown? Four?

The ridge out west is meaningless. It’s still a crud, garbage pac maritime airmass trapped over us. Same pattern next weekend. The Euro has been doing this ALL winter, it’s been absolutely horrible 

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20 minutes ago, snowman19 said:

The ridge out west is meaningless. It’s still a crud, garbage pac maritime airmass trapped over us. Same pattern next weekend. The Euro has been doing this ALL winter, it’s been absolutely horrible 

The ridge out west isnt meaningless. When was the last time this winter we had a great pacific ?

Yes the models have been crap in the long range but  I cant recall when the models had a big ridge in the west.

We need a big storm in the east because I'm not sure it will be cold enough but the Euro would get it done.

Cmc was close and gfs is an interior snowstorm with the gefs offshore.

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You know it’s a warm January when NYC doesn’t drop below 20 and HPN and ISP stay above 15.

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Jan
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Lowest Min Temperature 
Missing Count
1 1937 25 0
2 1990 24 0
- 1932 24 0
3 2002 21 0
- 1993 21 0
- 1953 21 0
4 2020 20 9
- 1949 20 0

 

Time Series Summary for WESTCHESTER CO AP, NY - Month of Jan
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Lowest Min Temperature 
Missing Count
1 1990 21 1
2 1953 18 0
3 1993 17 2
4 2020 16 12
- 2002 16 0
5 1960 15 0
Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jan
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Lowest Min Temperature 
Missing Count
1 1990 21 0
2 1993 18 0
3 2020 16 9
4 2002 15 0
- 1998 15 0
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22 minutes ago, Snow88 said:

I think it might finally be coming.  A lousy spring is on the way.

I wouldn't throw in the towel at this point Anthony. I'm beyond aggravated as you are, but I have this sneaky suspicion that we're going to get a KU event sometime in February/March. With a split flow along with an improving western ridge, the pattern looks very active. It's only a matter of time before everything lines up for us.

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