December 2018 General Discussion & Observations

[TJW014]

2 minutes ago, Ericjcrash said:

Huh? Too far south. Take your surprise 2" tomorrow night and be happy. 

That was my fault. I was looking at the GEM, not GFS. Lol. It's kinda a pain looking at my phone without glasses 5 minutes after you wake up.

[ILoveWinter]

What did the Euro show? Assuming not much since I don't see any chatter about it...

[Ericjcrash]

29 minutes ago, ILoveWinter said:

What did the Euro show? Assuming not much since I don't see any chatter about it...

 

[LongBeachSurfFreak]

My fear is we do see the NW trend. But just not enough. And we see DCA over to ACY get a decent hit while we partly cloudy.

[Ericjcrash]

6 minutes ago, LongBeachSurfFreak said:

My fear is we do see the NW trend. But just not enough. And we see DCA over to ACY get a decent hit while we partly cloudy.

Yeah. VA looks to be the place to be.

[North and West]

7 minutes ago, LongBeachSurfFreak said:

My fear is we do see the NW trend. But just not enough. And we see DCA over to ACY get a decent hit while we partly cloudy.

It happens, though. Next time we get a nice hit, they'll have sleet and rain.

[MJO812]

5 minutes ago, Ericjcrash said:

Yeah. VA looks to be the place to be.

Right now

[donsutherland1]

Overnight, there continued to be decent agreement among most of the guidance concerning the 500 mb height anomalies during the time a storm will be moving to the South Carolina coast. The EPS is used as a reference point in the chart below. The 0z GFS showed somewhat stronger and more expansive above average 500 mb height anomalies in the Northeast than the EPS. In contrast, the FV3 had somewhat weaker and less expansive above average 500 mb height anomalies in the Northeast (and was supported to a large extent by the GEFS). The result was that the storm came somewhat farther north on the FV3 than it did on the GFS. The GGEM was an outlier, a faster evolution of events and a notably different 500 mb pattern.

For now, my preference remains the EPS given its skill advantage at the lead time in question. However, a solution closer to the GEFS/FV3 remains on the table albeit at a somewhat lower probability than that shown on the EPS/ECMWF. Until a dramatically different 500 mb pattern and evolution show up on additional guidance, I believe the GGEM is an outlier. Its solution is least likely to verify.

The bottom line at this point: A higher probability of accumulating snow exists over the lower Mid-Atlantic region (especially portions of North Carolina and Virginia) than it does over the northern Mid-Atlantic/southern New England areas. One still can't rule out the possibility of some accumulations in that northern area. A GGEM scenario of a heavy snowfall in parts of the Northeast (interior sections on the 0z run) with a changeover to heavy rain on the coastal plain seems unlikely.

[donsutherland1]

6 hours ago, LibertyBell said:

Thanks Don, for the rigorous analysis!  I thought the 80" might have been slightly above what it should have been,but based on nearby reports, I thought the actual number should still have been higher than 70"  So somewhere between the 2011 number and the 80" figure is probably a safe bet.

I was thinking mid-70s. The NCDC has access to a lot of additional data and the ability to examine the suspect rain gauge. In the end, it appears that the final 1983 figure was retained.

[uncle W]

the 1983 total rainfall in NYC was suspect...at the time they thought it was at least 10% to high...They thought the gauge was broken but they did not know if and when it when haywire...for years the record was wiped clean...

[bluewave]

15 minutes ago, uncle W said:

the 1983 total rainfall in NYC was suspect...at the time they thought it was at least 10% to high...They thought the gauge was broken but they did not know if and when it when haywire...for years the record was wiped clean...

It almost looks like they just stuck the erroneous  total back in there since they didn’t want to leave the blank space for 1983. 

https://www.nytimes.com/1983/12/31/nyregion/city-s-rain-83-record-is-in-doubt.html

To no one's surprise, the Weather Service announced on Nov. 15 that the year's drenching rains in Manhattan had surpassed a record of 67.04 inches, set in 1972. As of early yesterday, additional rains were said to have brought the year's total to 80.56 inches.

But the Weather Service's data acquisition division in Garden City, L.I., suspected something was amiss because the Central Park readings were much higher than official measurements at Kennedy International, Newark International and La Guardia Airports.

So the gauge at Belvedere Castle in the park was taken apart. It was found to be leaky. A faulty weld apparently was allowing water to seep in the side and be measured with rain entering the calibrated opening.

No one knows how much rain fell in the park in 1983. But the Weather Service said that an official estimate based on nearby readings would be made and that ''it likely will be close to the record, either just above or just below.''

[donsutherland1]

18 minutes ago, uncle W said:

the 1983 total rainfall in NYC was suspect...at the time they thought it was at least 10% to high...They thought the gauge was broken but they did not know if and when it when haywire...for years the record was wiped clean...

That's correct. The 1983 NCDC summary, which was prepared at the time, contains the note:

"1983 precipitation was determined by NWS Eastern Region to be excessive due to malfunctioning equipment."

I have e-mailed the Eastern Region office for the final status concerning the 1983 figure. If or when I receive a reply, I will post it here.

 

[bluewave]

39 minutes ago, donsutherland1 said:

That's correct. The 1983 NCDC summary, which was prepared at the time, contains the note:

"1983 precipitation was determined by NWS Eastern Region to be excessive due to malfunctioning equipment."

I have e-mailed the Eastern Region office for the final status concerning the 1983 figure. If or when I receive a reply, I will post it here.

 

The highest total that I could find for the 5 boroughs Of NYC in 1983 was 65.00 at AVE V in Brooklyn.

https://xmacis.rcc-acis.org/

Time Series Summary for NEW YORK AVE V BROOKLYN, NY - Jan through Dec

1

1983

65.00

0

[purduewx80]

Bit of a norlun feature showing up over central NJ tomorrow. The ocean will come into play, producing steep low-level lapse rates that tap squarely into the DGZ. The inverted trof feature develops as a result of the incoming upper vort. I doubt that hi-res has nailed the location of this yet, but areas near ACY to as far north as BLM are in play. The probability for the city to see snowfall Wednesday appears to be slim, however. Some guidance indicates the potential for a max of 2-4" should the tail end of this feature set up inland. 

Most of the guidance w/ available soundings show 200-300 j/kg of CAPE where low-level lapse rates max out around 7.5.

[uncle W]

I met my wife in 1983 and our first date was in late August...There was a thunder storm that set a record rainfall for the date...In July Diana Ross got drenched in Central Park during a heavy thunder storm...

https://www.youtube.com/watch?v=rXWDwVY-270

[Toekneeweather]

Gfs through 72 hours is definitely north of its same time with the last run. Let’s see how it finishes?

[TJW014]

38 minutes ago, purduewx80 said:

Bit of a norlun feature showing up over central NJ tomorrow. The ocean will come into play, producing steep low-level lapse rates that tap squarely into the DGZ. The inverted trof feature develops as a result of the incoming upper vort. I doubt that hi-res has nailed the location of this yet, but areas near ACY to as far north as BLM are in play. The probability for the city to see snowfall Wednesday appears to be slim, however. Some guidance indicates the potential for a max of 2-4" should the tail end of this feature set up inland. 

Most of the guidance w/ available soundings show 200-300 j/kg of CAPE where low-level lapse rates max out around 7.5.

Hope so! I want to test out my camera on the snow. Will look cool during the sunrise Thursday morning if I can get something. 

[TJW014]

Just now, CarLover014 said:

Hope so! I want to test out my camera on the snow. Will look cool during the sunrise Thursday morning if I can get something. 

Watch though, I'll get more snow from that than I'll get from the next system  

[lagreeneyes03]

17 hours ago, donsutherland1 said:

He's from Fort Worth.

She

[Ericjcrash]

GFS and Canadian now show two distinctly coastal lows. The latter clips city east on the Canadian. 

[mikem81]

GFS para is a coastal scraper. Wonder if models are chasing convection and taking the SLP too far east. It has happened in the past with storms that surprised in the last few days and came well NW of initial modeling

[donsutherland1]

1 hour ago, lagreeneyes03 said:

She

My apologies.

[Gravity Wave]

Double barrel low feature also showing up on Para GFS.

[romba]

Take a shot every time someone says double barrel low or chasing convection this winter

 

This low’s chasin’ convection like it’s a skirt in the 80’s!

[Ericjcrash]

21 minutes ago, romba said:

Take a shot every time someone says double barrel low or chasing convection this winter

Well as far as the GFS has been concerned with this potential, we'd be hammered already.

[donsutherland1]

IMO, there were no appreciable changes in the upper air (500 mb) pattern on the EPS (mean) from the 0z run. With the 12z GGEM moving toward the broader model consensus, my confidence that this will primarily be a lower Mid-Atlantic/Southeast storm is increasing. There still remains some possibility that the precipitation could reach parts of the NYC region (especially central New Jersey southward), but the low (or lows depending on the guidance one is examining) will likely head east-northeastward out to sea and make a turn that is too wide to do more than brush the region. The storm's precipitation shield could miss altogether.

Among the cities that could be in line for a moderate and possibly significant snowfall from the 12/9-11 storm(s) are Asheville, Charlotte, Danville, Greensboro, Greenville-Spartanburg, Raleigh, Richmond, and Roanoke.

There remains a reasonable possibility that cities such as Baltimore, Hagerstown, and Washington could also pick up some accumulations, but this remains uncertain.

Note: The lead time involved still leaves latitude for changes.

[Ericjcrash]

1 minute ago, donsutherland1 said:

IMO, there were no appreciable changes in the upper air (500 mb) pattern on the EPS (mean) from the 0z run. With the 12z GGEM moving toward the broader model consensus, my confidence that this will primarily be a lower Mid-Atlantic/Southeast storm is increasing. There still remains some possibility that the precipitation could reach parts of the NYC region (especially central New Jersey southward), but the low (or lows depending on the guidance on is examining) will likely head east-northeastward out to sea and make a turn that is too wide to do more than brush the region. The storm's precipitation shield could miss altogether.

Among the cities that could be in line for a moderate and possibly significant snowfall from the 12/9-11 storm(s) are Asheville, Charlotte, Danville, Greensboro, Greenville-Spartanburg, Raleigh, Richmond, and Roanoke.

There remains a reasonable possibility that cities such as Baltimore, Hagerstown, and Washington could also pick up some accumulations, but this remains uncertain.

Yeah. Pretty remarkable how long guidance has honed in on a historic NC/VA blockbuster.

[MJO812]

1 minute ago, donsutherland1 said:

IMO, there were no appreciable changes in the upper air (500 mb) pattern on the EPS (mean) from the 0z run. With the 12z GGEM moving toward the broader model consensus, my confidence that this will primarily be a lower Mid-Atlantic/Southeast storm is increasing. There still remains some possibility that the precipitation could reach parts of the NYC region (especially central New Jersey southward), but the low (or lows depending on the guidance on is examining) will likely head east-northeastward out to sea and make a turn that is too wide to do more than brush the region. The storm's precipitation shield could miss altogether.

Among the cities that could be in line for a moderate and possibly significant snowfall from the 12/9-11 storm(s) are Asheville, Charlotte, Danville, Greensboro, Greenville-Spartanburg, Raleigh, Richmond, and Roanoke.

There remains a reasonable possibility that cities such as Baltimore, Hagerstown, and Washington could also pick up some accumulations, but this remains uncertain.

I disagree

There are a few members who are more northwest than the op and the mean had a nw lean to it.

Now we are back to a week to follow this storm. We are no where done here.

[MJO812]

26 minutes ago, romba said:

Take a shot every time someone says double barrel low or chasing convection this winter

 

This low’s chasin’ convection like it’s a skirt in the 80’s!

It happened in the jan 2016 storm and looked at the end result. The models were chasing the convection.

[donsutherland1]

1 minute ago, Ericjcrash said:

Yeah. Pretty remarkable how long guidance has honed in on a historic NC/VA blockbuster.

It's not often that such a situation happens, but I'm impressed with the consistency in the 500 mb pattern (which is similar to what it was for some of the past significant NC/VA December snowstorms).