December 2019

[weatherpruf]

48 minutes ago, bluewave said:

The -AO and -NAO won’t matter if the fast Pacific flow doesn’t relax. Notice how the record Pacific Jet keeps knocking down the PNA. 
 

 

How many years have we had this pacific jet now?

[White Gorilla]

1 hour ago, bluewave said:

The -AO and -NAO won’t matter if the fast Pacific flow doesn’t relax. Notice how the record Pacific Jet keeps knocking down the PNA. 
 

 

Wouldn't that depend on the strength of the NAO, AO negativity couplet?  Most definitely a pac jet on steroids is going to at least dampen big snow potential.  Also have to see how quickly or slowly the MJO traverses through the colder and warmer phases. 

[bluewave]

18 minutes ago, weatherpruf said:

How many years have we had this pacific jet now?

The uninterrupted unfavorable Pacific began last winter. Before that, the favorable intervals within a season more than made up for the unfavorable ones.

1 minute ago, White Gorilla said:

Wouldn't that depend on the strength of the NAO, AO negativity couplet?  Most definitely a pac jet on steroids is going to at least dampen big snow potential.  Also have to see how quickly or slowly the MJO traverses through the colder and warmer phases. 

It usually takes the -AO falling to -4 to -5 and the NAO -1 to -2 on the CPC official site. But we generally need a robust MJO 8 or a start warming event to pull that off. That extreme a drop can usually get the ridge to retrograde back to the West Coast boosting the PNA.

[binbisso]

I usually favor the Euro over the other operational models but the Euro just caved to the  GFS for the pre-Christmas storm. Verbatim it's a Miss but that is awfully close and a very nice-looking setup

[White Gorilla]

10 minutes ago, binbisso said:

I usually favor the Euro over the other operational models but the Euro just caved to the  GFS for the pre-Christmas storm. Verbatim it's a Miss but that is awfully close in a very nice-looking setup

Would rather see a miss now.  Have time to work out pattern evolution. 

[Monmouth_County_Jacpot]

1 minute ago, binbisso said:

I usually favor the Euro over the other operational models but the Euro just caved to the  GFS for the pre-Christmas storm. Verbatim it's a Miss but that is awfully close and a very nice-looking setup

Few hundred miles west we would be good

[bluewave]

6 minutes ago, binbisso said:

I usually favor the Euro over the other operational models but the Euro just caved to the  GFS for the pre-Christmas storm. Verbatim it's a Miss but that is awfully close and a very nice-looking setup

Lose that weak low over the GL and it might be better. But that fast flow Pacific has me concerned about a fly in the ointment. Also notice that other low racing east just  north of Montana. 

 

[binbisso]

4 minutes ago, bluewave said:

Lose that weak low over the GL and it might be better. But that fast flow Pacific has me concerned about a fly in the ointment. 

Or get the ridge out west more north to south then the Northeast to Southwest orientation as shown today  which would dig that Great Lakes shortwave South /west and then that could be fun.

[bluewave]

2 minutes ago, binbisso said:

Or get the ridge out west more north to south then the Northeast to Southwest orientation as shown today  which would dig that Great Lakes shortwave South /west and then that could be fun.

Yeah, that’s why a solid +PNA is so important.

[binbisso]

5 minutes ago, bluewave said:

Yeah, that’s why a solid +PNA is so important.

Agree and I see what you're saying about the fast Pack Flow as you can see the trough entering the West Coast and another one in Northwest Canada knocking down the ridge. Get rid of that low in Northwest Canada and extend that ridge Northward to drop the shortwave over the Great Lakes Southwest

[redbanknjandbigbasslakepa]

A fast Pac flow can be a good for us if we get the correct PNA orientation out west. If it’s more north to south we’ve had that ripping 200+ jet stream coming down the Rockies spawn plenty of big Gulf lows. 

[doncat]

1.92" rain total here...5.39" for month and 59.46" for year.

[SnoSki14]

17 minutes ago, redbanknjandbigbasslakepa said:

A fast Pac flow can be a good for us if we get the correct PNA orientation out west. If it’s more north to south we’ve had that ripping 200+ jet stream coming down the Rockies spawn plenty of big Gulf lows. 

A fast Pacific flow + extreme blocking is one of the best results a la 2010/2011 but that's a very rare combination.

In almost every other instance you'd want a more favorable Pacific over the Atlantic. Even the worst Atlantic pattern can be saved by a good Pacific.

[MJO812]

2 hours ago, bluewave said:

The -AO and -NAO won’t matter if the fast Pacific flow doesn’t relax. Notice how the record Pacific Jet keeps knocking down the PNA. 
 

 

The nao would matter because storms would have to redevelop  when they hit the block. 

[bluewave]

14 minutes ago, Snow88 said:

The nao would matter because storms would have to redevelop  when they hit the block. 

This is mostly a -AO though. The NAO is closer to neutral with a neutral to negative PNA. So the ridge axis on the current EPS is too far to the east. This favors late developers that deepen further offshore. Need to slow down that Pacific flow so the ridge can back up to the West Coast. 
 

 

 

[doncat]

Pressure changes....From 30.75" Thurs to 29.15" today.

[bluewave]

16 minutes ago, doncat said:

Pressure changes....From 30.75" Thurs to 29.15" today.

Too bad our local NWS doesn’t keep track of daily pressure records like other offices do.

 

[donsutherland1]

This afternoon was often foggy with occasional mist. Temperatures were in the lower 50s. Three photos from this afternoon:

[donsutherland1]

The soggy rainstorm that dumped widespread 1.00"-2.00" rain across the region with local amounts above 2.50" in places left in its wake fog, mist, and unseasonably mild temperatures. A cold front will bring noticeably cooler weather to the region tomorrow.

Select rainfall amounts through 7 pm included:

Boston: 1.35"; 2019 YTD: 48.08" (27th wettest year on record)
Bridgeport: 2.49"; 2019 YTD: 49.09" (10th wettest year on record)
Islip: 2.57"; 2019 YTD: 46.50" (22nd wettest year on record)
New York City: 1.97"; 2019 YTD: 50.99" (34th wettest year on record)
Newark: 1.49"; 2019 YTD: 56.33" (6th wettest year on record)
Providence: 2.00"; 2019 YTD: 49.60" (20th wettest year on record)

A number of locations saw rainfall amounts of 3.00" or above. Those locations included: Bellerose, NY: 3.02"; Centerport, NY: 3.13"; Centerport (1 SW), NY: 3.16"; East Locust Valley, NY: 3.43"; Killingsworth, CT: 3.16"; Milford, CT: 3.06"; Muttontown, NY: 3.08"; and, Woodbury, NY: 3.46".

Into the closing week of December, variability will likely continue to define to weather. As a result, much of the region could see additional snowfall through December 26, along with periodic intrusions of cold air. Whether the major cities see a 6" or greater snowstorm could depend, in large part, on the state of the teleconnections at the time of any storminess.

The first system will likely bring a light snowfall to the coastal plain and light to moderate snowfall to interior sections before transitioning to sleet, freezing rain, and then rain during the December 16-17 timeframe. This could be the kind of system that brings 2"-4" across northwestern New Jersey/northeastern Pennsylvania north and eastward to Albany; 1"-2" in Newark; and 1" or less to New York City and Long Island.

That storm will be followed by a short but sharp shot of cold. Parts of the region could experience the lowest temperatures so far this season. New York City could see the lowest temperature approach 20° and perhaps one day where the high temperature remains below 30°.

Another window of opportunity could be available during the December 21-23 timeframe. During that time, the Arctic Oscillation (AO) and NAO are forecast to be negative.

The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was +0.3°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.23°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20 and the recent cooling in Region 3.4 suggests that the base case remains viable.

The SOI was -11.31 today.

Today, the preliminary Arctic Oscillation (AO) figure was +1.213.

Since 1950, 13 years saw the AO average +1.000 or above for the first 15 days of December, which is very likely this year. Only 3 (23%) wound up with a colder than normal December in New York City (which appears likely at present). The most recent such case was December 1988 when New York City had a mean December temperature of 35.9°. 85% of such cases went on to record less than 30.0" seasonal snowfall in New York City and Newark. One notable exception was winter 2013-14 when 57.4" snow was recorded in New York City and 61.1" in Newark.

No significant stratospheric warming event appears likely through December 23. However, a brief period of warming could occur near 1 mb and above after December 20. Wave 2 activity is forecast to remain relatively weak. Overall, the stratosphere is forecast to remain cold into the fourth week of December on the EPS.

On December 13, the MJO was in Phase 2 at an amplitude of 1.301 (RMM). The December 12-adjusted amplitude was 1.120.

Large differences between the EPS and GEFS persist beyond Day 10. The GEFS is notably colder than the EPS with much of North America and the Northern Hemisphere covered by cold anomalies. Both show the coldest anomalies over a portion of northern Asia. The colder idea has more often than not prevailed since late autumn. However, the GEFS forecast for the EPO for the closing week of December has moved toward the EPS forecast (mainly EPO+).

When it comes to New York City's 4" or greater snowstorms during the second half of December, the AO is highly important. Since 1950, December 16-31 has seen 15 storms bring 4.0" or more snow to New York City. 73% occurred with an AO-. Further, 80% of the 6" or greater snowstorms during this timeframe occurred when the AO was negative. Even as the PNA and NAO had a lesser impact on the 4" or greater snowstorms, an NAO- was present in 70% of the 6" or greater snowstorms during that timeframe and a PNA+ was also present during 70% of the 6" or greater snowstorms.

Based on sensitivity analysis applied to the latest guidance, there is an implied 64% probability that December will wind up colder than normal in New York City.

[CIK62]

The next 8 days are suddendly averaging 32degs., or about -4.5degs. BN.

Month to date is  -1.3[38.8].           Should be about -2.4[36.3] by the 23rd.

Models on a colder/drier(snowless- anyway)kick this run.

43* here at 6am.

[MJO812]

Gfs shows the big  storm hitting  us on the 22nd. Gefs has big hits.

[bluewave]

This was a top 3 wettest first 2 weeks of December around the area. The recent warm up shrunk the cold departures to 0 to -1.3.

Time Series Summary for JFK INTL AP, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Total Precipitation Dec 1 to Dec 14	Missing Count
1	2019-12-14	5.88	0
2	2014-12-14	5.30	0
3	1996-12-14	5.04	0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Total Precipitation Dec 1 to Dec 14	Missing Count
1	1983-12-14	6.32	0
2	1996-12-14	5.70	0
3	2019-12-14	5.05	0

December temperature departures through the 14th.

EWR...-0.9

NYC....-1.3

LGA.....-1.3

JFK.....-1.3

BDR....-0.6

ISP......-0.2

 

[the_other_guy]

Some cool photos around JFK this morning as the weather moves out

[qg_omega]

Looks like a very strong but in and out cold blast on Thursday?

[bluewave]

28 minutes ago, qg_omega said:

Looks like a very strong but in and out cold blast on Thursday?

It should be cold enough to maintain the monthly cold departures over the Northeast. Then we see what happens during the last week of December. While the rest of the country has been mild, a small area of cold departures remains over the Northeast.

 

[MJO812]

32 minutes ago, qg_omega said:

Looks like a very strong but in and out cold blast on Thursday?

That should set the table for the possible coastal storm this upcoming weekend

[bluewave]

38 minutes ago, Snow88 said:

That should set the table for the possible coastal storm this upcoming weekend

Need to lose that northern stream low over the GL so it doesn’t suppress the southern stream low.

[MJO812]

12 minutes ago, bluewave said:

Need to lose that northern stream low over the GL so it doesn’t suppress the southern stream low.

Gfs and gefs look good

[bluewave]

6 minutes ago, Snow88 said:

Gfs and gefs look good

The GFS is currently on its own. The Euro, UKMET, and CMC have a low in the Great Lakes and a separate southern stream low.

[MJO812]

34 minutes ago, bluewave said:

The GFS is currently on its own. The Euro, UKMET, and CMC have a low in the Great Lakes and a separate southern stream low.

Gfs has support from the gefs and we know how well the euro has been this season.

Euro came on board at 0z. I'm already seeing some media outlets already sounding the alarm lol 

Pattern supports a storm . The pac has to cooperate.