December 2018 General Discussion & Observations

[NEG NAO]

WPC thinks this stays south

[Rtd208]

Picked up 0.67" of rain so far today.

Storm total 0.78"

[CIK62]

51 minutes ago, bluewave said:

Seems like a pretty straightforward MJO driven pattern for December. Colder than normal through our winter storm potential in about a week. Followed by a mid-December thaw. Then a return to colder later in the month with more winter storm threats. Just don't get too hung up on storm details until they get within the NAM and Euro best range.

 

 

The next 30 days breakdown as of today to:   21AN  9BN and streaky.    Warming of the Stratosphere might change week 3-4, I hope.      Like the last 62 months:    41AN   21BN, including 20 straight AN months at one point.  

[MJO812]

I don't like how the tellies look near the storm. 

 

They trended the wrong way this past week. It's early to give up but it's not looking good

[NEG NAO]

the 18Z GFS Para is much further north - anyone throwing in the towel 7 days out is.....

[Toekneeweather]

4 hours ago, NEG NAO said:

just ask yourself - how many systems were suppressed this season so far ? The answer is obvious.....

I was just going through the latest GFS para and GFS and to me it looks like plenty of opportunities. They all miss as of right now but I counted about 3 strong systems that are coming east, how far north they get is up to Mother Nature but we need to just take a step back and realize that we have so many storm chances to close out this obviously record precipitation year. It’ll be decently cold after tomorrow so chances will start rolling in. It won’t be so cold so I don’t think suppression will come in but the blocking could make it drier. But if we do get hit, we will get a good hit!

 

and winter doesnt begin for another 3 weeks roughly.

 

[donsutherland1]

As of 7 pm, much of the region saw 0.50"-1.00" rain, which was in line with modeled outcomes. Notable exceptions were Bridgeport and Islip where more than 1.00" fell.

As of 7 pm, total annual precipitation and 2018's rank among the wettest years is provided for select cities:

During Friday into Saturday, low pressure will be developing and gaining moisture as it tracks near the Gulf Coast. Afterward, it will gradually turn east-northeast and move off either the Georgia or South Carolina coasts. Given repeated cycles of the guidance, this idea is one in which I have high confidence.

Afterward, questions begin to emerge. The storm could continue to track generally east-northeastward while making a wide turn more to the north. A second possibility is that it could turn more sharply northward. The latter situation would present a greater risk of accumulating snowfall, potentially a moderate accumulation, in much of the northern Middle Atlantic region. However, issues concern weak low pressure that will be tracking eastward from Quebec and a vorticity maximum that could be present well off the South Carolina-Georgia border. The presence of both those factors increases the risk of the former scenario.

The forecast 500 mb anomalies (especially those on the EPS) would strongly favor the former scenario.

After another 24-30 hours of unseasonably mild readings, colder air will return to the eastern United States. By the next weekend, the focus of attention could be a large storm that is moving off the Southeast coast.

Right now, the EPS is forecasting 500 mb anomalies that are reasonably similar to the composite for significant snowstorms (prior to 12/20) in parts of North Carolina. Such storms typically result in little or no snowfall north of the Mason-Dixon Line.

The best match for the forecast 500 mb height anomalies is the December 2-3, 1896 snowstorm.

The following snowstorms dumped 6" or more snow at Raleigh prior to December 20:

December 2-3, 1896: 7.5"
December 12-13, 1917: 7.1"
December 17, 1930: 7.0"
December 11, 1958: 9.1"

Snowfall for select cities from those storms was as follows:

December 2-3, 1896:
Greenville-Spartanburg, SC: 10.5"
New York City: None
Philadelphia: None
Washington, DC: None

December 12-13, 1917:
Greenville-Spartanburg, SC: 5.7"
New York City: 8.1"
Philadelphia: 2.3"
Washington, DC: 3.0"

December 17, 1930:
Greenville-Spartanburg, SC: 14.4"
New York City: None
Philadelphia: None
Washington, DC: 2.0"

December 11, 1958:
Greenville-Spartanburg, SC: 0.1"
New York City: Trace
Philadelphia: None
Washington, DC: Trace

Taking into consideration the EPS anomalies and the historical data, I have moderate confidence that the storm will eventually make a wide turn. As a result, at least from this point in time, a glancing blow might be possible, but the odds of a moderate to possibly significant snowfall in the New York City area could be low. Nevertheless, at these large lead times, significant changes remain possible. Thus, higher confidence in the details won't likely begin to emerge until the middle of the week. Therefore, even as the early data and historical experience with the currently forecast 500 mb maps suggest much greater prospects of a lower Mid-Atlantic, the lead time leaves some opportunity for changes in the forecast 500 mb pattern.

Regardless of the outcome, winter 2018-19 still appears to be in line for much above average snowfall.

[Midlo Snow Maker]

Awesome write-up Don you're like a fine wine with age 

[donsutherland1]

14 minutes ago, Midlo Snow Maker said:

Awesome write-up Don you're like a fine wine with age 

Thanks for the kind words.

[doncat]

1.03" for event and 63.54" for the year. Dreary day with drizzle and fog.

[NEG NAO]

0Z GEM MECS

[MJO812]

2 minutes ago, NEG NAO said:

0Z GEM MECS

Icon is also north but rain

Gfs is slightly more north but I'm not expecting it to trend northward yet .

[LibertyBell]

8 hours ago, Snow88 said:

I don't like how the tellies look near the storm. 

 

They trended the wrong way this past week. It's early to give up but it's not looking good

I remember a similar thing happened in December 2010 when we just missed out on a system that went out to sea and then after Christmas we got the big one.

[LibertyBell]

17 hours ago, bluewave said:

I wonder if there was some type of error at the NYC rain gauge in 1983. It was the only station in the area to reach 80 inches of precipitation that year. In any event, several stations are in the top 10 for 2018 updated through yesterday.

Westtest years around the area

EWR

#1........69.91....2011

#2........65.50....1983

#12......52.38....2018

NYC

#1.......80.56.....1983

#2.......72.81.....2011

#9.......59.09.....2018

LGA

#1......65.34.....2011

#2......60.84.....1983

#9......51.94.....2018

JFK

#1.....59.12......1983

#2....60.84.......1983

#9....50.64.......2018

HPN

#1....74.15.......1983

#2....73.29.......2011

#20...53.15......2018

ISP

#1....65.32......1989

#5....57.67......2018

 

Chris which one of these is for 1983?

JFK

#1.....59.12......1983

#2....60.84.......1983

#9....50.64.......2018

 

Number 1 and 2?

 

1983 was amazing for how hot and moisture laden it was!

[LibertyBell]

16 hours ago, donsutherland1 said:

Interesting question. Is it possible that the original diagnosis of the faulty weld was incorrect? If not, the records should be revised as appropriate. Accuracy matters.

Personally, I believe 2011 may hold the record or be slightly behind. Statistically, the 1983 figure is so extreme, the faulty gauge seems like a reasonable explanation. However, White Plains recorded 74.15" that year, so a mid-70s figure might be plausible.

Don and Chris, I distinctly remember 1983 being extremely wet and hot- we did set a record that year, the only question is by how much?

I'm amazed that 2011 had so much, I dont remember it being as wet as 1983 was, 2011 in my memory just had the extremely wet August.  And also amazed that 2005 isn't up on that list.

 

[Toekneeweather]

2 hours ago, Snow88 said:

Icon is also north but rain

Gfs is slightly more north but I'm not expecting it to trend northward yet .

Gfs is the worst model it’s pronably worst than navgem

 

lets just say the euro looked a lot better than its previous runs

[CIK62]

Next 8 days averaging 36degs., or about 4degs. BN.

EPS and GEFS, both look snow free.

[TJW014]

Is there anything to be concerned with what the GEM is hinting at between hour 66-84?

[MJO812]

1 hour ago, CIK62 said:

Next 8 days averaging 36degs., or about 4degs. BN.

EPS and GEFS, both look snow free.

Eps isn't snow free

Euro trended north and while I said yesterday things don't look good, we shouldn't rule out the north trend like we always get with these storms.

[bluewave]

5 hours ago, LibertyBell said:

Chris which one of these is for 1983?

 

1983 was amazing for how hot and moisture laden it was!

The only weather events that I can remember from 1983 were the Feb snowstorm, spring flash floods, and summer heat. Plenty of basement flooding in Long Beach during that spring deluge. 

Top wettest years at JFK

#1....59.12....1983

#2...57.18.....1975

#3...55.78.....2011

#4...55.73.....1989

#5...53.22.....1984

#6...51.57.....2018

[Ericjcrash]

Man the Carolina's look to be in line for historic snows.

[gravitylover]

8 hours ago, NEG NAO said:

0Z GEM MECS

Yeah that looks like a pretty fair chance of rain on LI so many posters here will discount it as being no good  

[Ericjcrash]

9 minutes ago, gravitylover said:

Yeah that looks like a pretty fair chance of rain on LI so many posters here will discount it as being no good  

The only reason it should be discounted is the fact its several hundred miles north of everything esle.

[Stormlover74]

Looks like our first extended dry streak in a while. Maybe 10 days or more if the weekend storm stays south

[MJO812]

24 minutes ago, Ericjcrash said:

Man the Carolina's look to be in line for historic snows.

Yes right now but we have been through this road many times

[MJO812]

The tellies this morning are a little better if you want snow up here

 

PNA will be rising  to positive around the timeframe of the storm

 

NAO will be positive

AO will be negative

[donsutherland1]

6 hours ago, LibertyBell said:

Don and Chris, I distinctly remember 1983 being extremely wet and hot- we did set a record that year, the only question is by how much?

I'm amazed that 2011 had so much, I dont remember it being as wet as 1983 was, 2011 in my memory just had the extremely wet August.  And also amazed that 2005 isn't up on that list.

 

1983 was exceptionally wet. A local maximum might have existed in a small area running from near Central Park into lower Westchester County.

Upon final review, the decision to leave the 1983 record intact could well have been based on a combination of radar (albeit limited compared to today's), local sites, and statistical analysis. The issue with the rain gauge may have been re-examined and found insignificant.

The 1983 figure is 4.3σ above the historic mean annual precipitation (1869-2017) and 0.9σ above the 2011 figure of 72.81". I looked for other sites with similar or greater statistical differences. Currently, Wilmington, NC's 2018 figure of 95.82" is is 4.5σ above the historic mean annual precipitation (1871-2017) and 1.3σ above the second highest figure (83.65", 1877). The most extreme statistical difference that I found (and my search was not all-inclusive) was at Nashua (2 NNW). There, the 2008 record of 82.19" is  4.9σ above the historic mean annual precipitation (1886-2017) and 2.2σ above the second highest figure (60.64", 2011). Therefore, in the larger context of precipitation records, New York City's 1983 amount is not unprecedented when it comes to statistical comparisons.

Nevertheless, it's still plausible that the 1983 figure was somewhat lower than the 80.56" amount that was recorded. However, after having looked for similar or greater statistical outliers, my confidence in the 1983 figure is greater than it was yesterday prior to that examination. Overall, I have confidence in the judgment made by the National Climatic Data Center.

 

[Brasiluvsnow]

Thank You guys for posting so much information. Im sure many people learn a lot from you guys not just myself .

[TJW014]

29 minutes ago, Brasiluvsnow said:

Thank You guys for posting so much information. Im sure many people learn a lot from you guys not just myself .

I've learned a lot too. Especially since my goal is to be a meteorologist in the future. I've been addicted since I was five.

[LongBeachSurfFreak]

Let’s see if we can get the NW trend that the models have had as we get closer to events the last few winters. Right now I would be allot more excited if I were down in DCA then here though...