December 2022

[donsutherland1]

Morning thoughts…

Today will be partly to mostly sunny and cool.  High temperatures will reach the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include:

New York City (Central Park): 40°

Newark: 41°

Philadelphia: 41°

The dry weather will continue through Wednesday.

Normals:

New York City: 30-Year: 43.3°; 15-Year: 44.1°

Newark: 30-Year: 43.8°; 15-Year: 44.8°

Philadelphia: 30-Year: 45.0°; 15-Year: 46.0°

[SnoSki14]

This mornings GFS is a flash freeze with 60+ gusts possible

Temps crash from near 60 to teens in 6-12 hrs

[wdrag]

Looks like everyone is reading the models. My primary concerns for membership.

Poconos: A little ice or snow to start Thursday afternoon-evening, shouldn't last too long and probably minimal impact. A potentially far more dangerous situation is possible Friday when a 1-2 hour period of brief intense snowfall may occur as temperatures plummet through the 20s. If this occurs, it will be difficult to manage if traveling in this 2 hour window. Snowfall generally under an inch or 2, but if it occurs, would result in slippery travel everywhere. Timing and confidence of occurrence is below average but sometime between Noon and 6PM. Worthy of monitoring. 

Otherwise the main story is damaging wind that will make headlines from the Great Lakes and Ohio Valley, throughout the northeast USA. Looks like a period or two of scattered 55-65 MPH wind gusts is likely from VA northward to Canada. If you don't have a generator, be aware that if power goes out, you'll need to depend on other SAFE sources for heat and communication. This is because the coldest air of the season so far, should be in place by Saturday morning with subzero nightitme wind chills in the I-84 corridor northward and near zero wind chill in the cities from Atlanta to Boston.

Due to the expected heavy rain: post cold frontal icing of any remaining runoff (road shoulders etc) is possible by Saturday morning.

 

[LibertyBell]

58 minutes ago, donsutherland1 said:

December 1989 had 1.4” of snow. The remainder of the winter saw 7.3” of snow. 

Thanks!  Was the AO very negative that month?

[LibertyBell]

38 minutes ago, wdrag said:

Looks like everyone is reading the models. My primary concerns for membership.

Poconos: A little ice or snow to start Thursday afternoon-evening, shouldn't last too long and probably minimal impact. A potentially far more dangerous situation is possible Friday when a 1-2 hour period of brief intense snowfall may occur as temperatures plummet through the 20s. If this occurs, it will be difficult to manage if traveling in this 2 hour window. Snowfall generally under an inch or 2, but if it occurs, would result in slippery travel everywhere. Timing and confidence of occurrence is below average but sometime between Noon and 6PM. Worthy of monitoring. 

Otherwise the main story is damaging wind that will make headlines from the Great Lakes and Ohio Valley, throughout the northeast USA. Looks like a period or two of scattered 55-65 MPH wind gusts is likely from VA northward to Canada. If you don't have a generator, be aware that if power goes out, you'll need to depend on other SAFE sources for heat and communication. This is because the coldest air of the season so far, should be in place by Saturday morning with subzero nightitme wind chills in the I-84 corridor northward and near zero wind chill in the cities from Atlanta to Boston.

Due to the expected heavy rain: post cold frontal icing of any remaining runoff (road shoulders etc) is possible by Saturday morning.

 

Thanks Walt, this is VERY important especially since the most traffic accidents occur in under 1" and 1-3" of snow!

[SnoSki14]

06z GFS looked even worse for gusts than Euro but I'm not sure 

[LibertyBell]

3 minutes ago, bluewave said:

Models have one of the strongest lows to track through the Great Lakes in December. Pressures near 970 mb against a 1040 mb high to the east will create a 70mb gradient. The finer details of where the secondary forms will determine the ceiling for wind gusts. But the floor looks like a minimum of 60-70 mph. We get our usual warm up near the solstice to low 60s. This is followed by a rapid drop to 15-20° in NYC over the weekend. 

 

Chris, I see a lot of mentions of "luck" in our "great" pattern and I wanted to ask you, as an analyzer of patterns how much does "luck" play into patterns?  I feel like there are certain nuances that are not captured by models (like the warm pool that you mentioned) that are far more important than luck.  Because here's the thing-- luck can maybe account for one bad outcome-- but multiple bad outcomes in a row?  No, there has to be something the models are missing and that is the nuance in the pattern  or climate conditions that makes it not so great that I was referencing.

 

Weather science by its very nature is imperfect and because we don't know all things and aren't omniscient I feel like we need to take a results based approach to what is or isn't a great pattern.  The only sure thing is if a pattern produces for you then that pattern was great for you.  Of course this is all relative in terms of what people mean by "great" and we must also allow for some variations like if there is a mix or rain/snow line nearby or if there is a grazer, etc.

It's like with the storm last January, was that luck that the heavy snow only made it as far west as Queens and Brooklyn? I could see that accounting for maybe 50 miles but probably not more than that.  

 

 

[LibertyBell]

11 minutes ago, bluewave said:

Models have one of the strongest lows to track through the Great Lakes in December. Pressures near 970 mb against a 1040 mb high to the east will create a 70mb gradient. The finer details of where the secondary forms will determine the ceiling for wind gusts. But the floor looks like a minimum of 60-70 mph. We get our usual warm up near the solstice to low 60s. This is followed by a rapid drop to 15-20° in NYC over the weekend. 

 

Wow I've not seen such a widespread area of 60+ mph winds forecast before outside of tropical season, both inland and near the coast.  And 70+ mph for the city and Long Island.

When was the last time we had something like this-- Sandy?  Or have we had that since?

[wdrag]

53 minutes ago, LibertyBell said:

Thanks Walt, this is VERY important especially since the most traffic accidents occur in under 1" and 1-3" of snow!

Uncertainty this far in advance but by 11AM Tuesday, we'll know what the NAM and RDPS models say (72-84 hour).  Let's see if global models lose this prior to tomorrow morning. I don't think they will.

Globals since the EC switched inland cutter with the 12z/16 (last Friday) cycle have been onto this sort of wind/back end scenario for the Appalachians. 

Gone for the rest of the day. 

[LibertyBell]

26 minutes ago, bluewave said:

Yeah, the GFS and around 20 EPS members have a stronger secondary low in Eastern PA with a tighter gradient. So they have gusts over 70 mph. We probably won’t know for a few days which idea is correct.
 

 

Wow 70-75 mph winds here and 77 mph on the Jersey shore and even 70 mph up by Scranton, Wilkes Barre and Hazelton would be truly horrendous.

How long would these winds last for Chris (above 60 mph I mean) and what would be the temperatures around the time of the highest wind gusts?  Thanks!

 

[SnoSki14]

2 minutes ago, LibertyBell said:

Wow 70-75 mph winds here and 77 mph on the Jersey shore and even 70 mph up by Scranton, Wilkes Barre and Hazelton would be truly horrendous.

 

I highly doubt we'll see that. Winds rarely get as strong as forecast. Usually models tone it down as we get closer. 40-50mph is more probable 

Some places could get near 60 though if the warm sector really over performs 

[LibertyBell]

1 minute ago, SnoSki14 said:

I highly doubt we'll see that. Winds rarely get as strong as forecast. Usually models tone it down as we get closer. 40-50mph is more probable 

Some places could get near 60 though if the warm sector really over performs 

I'm worried about power outages we had them in NE PA even with the storm just last week.

Might have widespread power outages even with those lower wind speeds.  I'd like to know how long these winds are supposed to last for and how cold it will be when the winds are peaking.

 

[Big Jims Videos]

Models performed well this past storm regards to wind. Top gust was a 51 I saw at Harvey Cedars.  Lots of places in upper 40s along the beach.  As long as there's not much easterly wind component to this system erosion hopefully won't be as bad as last Friday. 

[LibertyBell]

Just now, Big Jims Videos said:

Models performed well this past storm regards to wind. Top gust was a 51 I saw at Harvey Cedars.  Lots of places in upper 40s along the beach.  As long as there's not much easterly wind component to this system erosion hopefully won't be as bad as last Friday. 

Historically it seems that southeast winds are the worst for tree damage and power outages too (?)

 

[bluewave]

53 minutes ago, LibertyBell said:

Chris, I see a lot of mentions of "luck" in our "great" pattern and I wanted to ask you, as an analyzer of patterns how much does "luck" play into patterns?

Sure there is luck sometimes. But this storm is classic long range model bias recognition case. All the guidance has been underestimating the ridge east of New England for years day 8-15. Below is just the most recent 90 day model error which is more of the same.

 

 

[Allsnow]

12 minutes ago, SnoSki14 said:

I highly doubt we'll see that. Winds rarely get as strong as forecast. Usually models tone it down as we get closer. 40-50mph is more probable 

Some places could get near 60 though if the warm sector really over performs 

Agree. Sell on any big wind issues. The gfs is the only one showing it. That should tell you all you need to know 

[CIK62]

The next 8 days are averaging    36degs.(30/43) or +2.

Month to date is    40.9[+0.2].             Should be   39.4[+0.7] by the 27th.

Reached 39 here yesterday.

Today:   36-39, wind w. to nw.-breezy, m. sunny, 30 tomorrow AM.

32*(75%RH) here at 6am.       31* at 7am.      32* at 9am.       35* at Noon.        37* at 2pm.        36* at 3pm.      35* at 4pm.

[Brian5671]

6 minutes ago, bluewave said:

Sure there is luck sometimes. But this storm is classic long range model bias recognition case. All the guidance has been underestimating the ridge east of New England for years day 8-15. Below is just the most recent 90 day model error which is more of the same.

 

 

That ridge has also been keeping us warmer-the big warm blob of water causing a positive feedback loop on the ridge as well.

[Brian5671]

2 hours ago, SnoSki14 said:

This mornings GFS is a flash freeze with 60+ gusts possible

Temps crash from near 60 to teens in 6-12 hrs

We won't see a flash freeze though-those almost never verify-the precip will shut off and the winds and incoming dry air will dry paved surfaces before we breach freezing temp of 32

[MJO812]

Just now, Brian5671 said:

We won't see a flash freeze though-those almost never verify-the precip will shut off and the winds and incoming dry air will dry paved surfaces before we breach freezing temp of 32

Sadly this is true 

[LibertyBell]

21 minutes ago, bluewave said:

Sure there is luck sometimes. But this storm is classic long range model bias recognition case. All the guidance has been underestimating the ridge east of New England for years day 8-15. Below is just the most recent 90 day model error which is more of the same.

 

 

Right this is the nuance they are missing.  I can buy luck for isolated events and small deviations like 50 miles but not repeated huge global level variations like this.

 

[LibertyBell]

12 minutes ago, MJO812 said:

Sadly this is true 

I don't know of anyone who actually wants a flash freeze, they cause horrible accidents across multiple vehicles.

 

[wdrag]

Just in case no one knows: and this can be shared with all other forums.  Below from an NCEP representative. 

The GFSv16.3 upgrade that occurred on 11/30 DID contain a correction to how snow depth is computed.    We are confident that this is a very positive change to the model.

 

 

I noticed this for the Dec 15 event... Positive snow depth change.

 

Walt

 

[donsutherland1]

1 hour ago, LibertyBell said:

Thanks!  Was the AO very negative that month?

There was a 19-day period of blocking (December 3-21). The AO fell below -3 on two days during that blocking. The blocking rapidly dissipated starting on December 22, the cold departed shortly afterward (but not before a historic Southeast snowstorm) and then the remainder of the winter was generally very mild. The monthly average AO was -0.621. This month, we'll likely average well below -2.

[LibertyBell]

1 minute ago, donsutherland1 said:

There was a 19-day period of blocking (December 3-21). The AO fell below -3 on two days during that blocking. The blocking rapidly dissipated starting on December 22, the cold departed shortly afterward (but not before a historic Southeast snowstorm) and then the remainder of the winter was generally very mild. The monthly average AO was -0.621. This month, we'll likely average well below -2.

What was the cause for the extreme cold that made that monthly average a historic 25.5....was that the coldest December on record by average temp, Don?

 

[WestBabylonWeather]

Big flash freeze Friday night? Dangerous 

[the_other_guy]

Just landed at O Hare. 10F with a light dusting on ground.

 

They have winter

[weatherpruf]

29 minutes ago, LibertyBell said:

I don't know of anyone who actually wants a flash freeze, they cause horrible accidents across multiple vehicles.

 

Personal injury lawyers...

[Volcanic Winter]

1 hour ago, LibertyBell said:

Chris, I see a lot of mentions of "luck" in our "great" pattern and I wanted to ask you, as an analyzer of patterns how much does "luck" play into patterns?  I feel like there are certain nuances that are not captured by models (like the warm pool that you mentioned) that are far more important than luck.  Because here's the thing-- luck can maybe account for one bad outcome-- but multiple bad outcomes in a row?  No, there has to be something the models are missing and that is the nuance in the pattern  or climate conditions that makes it not so great that I was referencing.

 

Weather science by its very nature is imperfect and because we don't know all things and aren't omniscient I feel like we need to take a results based approach to what is or isn't a great pattern.  The only sure thing is if a pattern produces for you then that pattern was great for you.  Of course this is all relative in terms of what people mean by "great" and we must also allow for some variations like if there is a mix or rain/snow line nearby or if there is a grazer, etc.

It's like with the storm last January, was that luck that the heavy snow only made it as far west as Queens and Brooklyn? I could see that accounting for maybe 50 miles but probably not more than that.  

 

 

It just appears that the storm track set up shop to our west, with the east end of the trough being too far west. 

IMHO I believe we’ve been over thinking this a bit. We had the ingredients but the trough axis wasn’t lined up properly for us to snow because the storm track is supporting cutters instead of coastals. And I think that ties into what’s been discussed about the 50/50 ridge from the extra warm SST’s. Simplest explanation is that pushed back on the trough and messed up the storm track for us keeping us on the torch side. 

[LibertyBell]

9 minutes ago, Volcanic Winter said:

It just appears that the storm track set up shop to our west, with the east end of the trough being too far west. 

IMHO I believe we’ve been over thinking this a bit. We had the ingredients but the trough axis wasn’t lined up properly for us to snow because the storm track is supporting cutters instead of coastals. And I think that ties into what’s been discussed about the 50/50 ridge from the extra warm SST’s. Simplest explanation is that pushed back on the trough and messed up the storm track for us keeping us on the torch side. 

Right and it's such a fine line in these patterns, the storm track is what makes or breaks a season.