October 2019 General Discussions & Observations Thread

[bluewave]

This has to be one of the more convective systems that we have seen this time of year. Check out the big convective blob low pressure jumps of the last 2 NAM runs. Next several runs should be interesting.
 

 

[LibertyBell]

11 minutes ago, uofmiami said:

41.9 in Syosset and 40.7 in Muttontown this morning.

Both were colder than KFOK!

 

[LibertyBell]

11 minutes ago, bluewave said:

This has to be one of the more convective systems that we have seen this time of year. Check out the big convective blob low pressure jumps of the last 2 NAM runs. Next several runs should be interesting.
 

 

Will most of the heavy rain be occurring during the late night hours?

[Cfa]

45 for the low here. Car thermometer picked up some low 40’s in the usual cold pockets.

[donsutherland1]

The recent dry spell has led to New York City's precipitation having fallen below normal on a year-to-date basis. In addition, the implied probability of New York City's seeing 50" or more precipitation this year has decreased to 45%.

However, there is strong model consensus that the region will likely experience its biggest rainstorm in several months as a strong nor'easter moves across western Long Island into New England. Widespread 1"-2" rainfall amounts with local amounts in excess of 3" appears likely tomorrow into Thursday.

Below is a summary of the precipitation status for select cities:

[purduewx80]

28 minutes ago, bluewave said:

This has to be one of the more convective systems that we have seen this time of year. Check out the big convective blob low pressure jumps of the last 2 NAM runs. Next several runs should be interesting.

No doubt. I think convection (w/ or w/o lightning) will probably be the culprit for damaging winds, in addition to the potential sting jet. Both seem to favor LI and points east-northeast along the coast of southern New England. The Gulf Stream and anomalous warmth to its north likely will be factoring into the convective potential.

[LibertyBell]

2 minutes ago, purduewx80 said:

No doubt. I think convection (w/ or w/o lightning) will probably be the culprit for damaging winds, in addition to the potential sting jet. Both seem to favor LI and points east-northeast along the coast of southern New England. The Gulf Stream and anomalous warmth to its north likely will be factoring into the convective potential.

I was going to ask, do you think the contrast between the Gulf Stream and our own offshore waters will cause the highest winds just offshore?

It reminds me of a weaker version of the March 2010 noreaster that gave us hurricane force gusts on the south shore while the winds were much weaker on the north shore.

 

[LibertyBell]

14 minutes ago, donsutherland1 said:

The recent dry spell has led to New York City's precipitation having fallen below normal on a year-to-date basis. In addition, the implied probability of New York City's seeing 50" or more precipitation this year has decreased to 45%.

However, there is strong model consensus that the region will likely experience its biggest rainstorm in several months as a strong nor'easter moves across western Long Island into New England. Widespread 1"-2" rainfall amounts with local amounts in excess of 3" appears likely tomorrow into Thursday.

Below is a summary of the precipitation status for select cities:

The low is going to move across western LI, Don?  I thought the center was going to pass east of us, between Boston and Cape Cod?  Do you have a precip tally for JFK?  I think it's even less than Islip.

 

[purduewx80]

2 minutes ago, LibertyBell said:

I was going to ask, do you think the contrast between the Gulf Stream and our own offshore waters will cause the highest winds just offshore?

The highest winds will occur wherever the warm sector sets up (especially from 950-925mb). A shallow surface inversion is likely for most areas near the coast, but this can be overcome by convection based just above the surface.  Deeper inversions inland should prevent stronger winds there Wed PM but everyone will see W/NW wind gusts Thursday.

The SST anomalies will become more important later in the winter; the Gulf Stream positioned so close to a cold continent acts as a natural baroclinic zone for coastal storms. 

[MJO812]

Long range op runs and ensembles still show a change to colder weather as we head deeper into October.  I wouldn't be shocked to see places  get their 1st flakes as we head into November especially inland areas. 

[Stormlover74]

[MJO812]

Just now, Stormlover74 said:

A lot of rain for the NYC  area and Inland areas. Winds arent strong at all due to the dual structure.

[Brian5671]

1 minute ago, Snow88 said:

A lot of rain for the NYC  area and Inland areas. Winds arent strong at all due to the dual structure.

I have to doubt the dual low thing.   Seems odd for such a strong system.  My guess is one low, closer to the coast.    

[NJwx85]

This looks more to me like a strong frontal passage. We need the surface low to come up the NJ coast instead of into Long Island in order to get into the stronger part of the storm. With that being said, looks like many areas are in for 2-3" of rain in a short period.

[donsutherland1]

1 hour ago, LibertyBell said:

The low is going to move across western LI, Don?  I thought the center was going to pass east of us, between Boston and Cape Cod?  Do you have a precip tally for JFK?  I think it's even less than Islip.

 

One is dealing with dual centers. On the 0z ECMWF, between hours 48 and 51, a developing second center crosses western/central Long Island while another center is offshore. The second center rapidly intensifies and reaches just under 980 mb over Rhode Island and continues north-northeastward into eastern New Hampshire by 60 hours. The offshore center passes southeast of Nantucket and then into the Gulf of Maine from 54 hours to 60 hours.

JFK has received 39.07" precipitation, which is 4.89" above normal for this time of year.

 

[LibertyBell]

9 minutes ago, donsutherland1 said:

One is dealing with dual centers. On the 0z ECMWF, between hours 48 and 51, a developing second center crosses western/central Long Island while another center is offshore. The second center rapidly intensifies and reaches just under 980 mb over Rhode Island and continues north-northeastward into eastern New Hampshire by 60 hours. The offshore center passes southeast of Nantucket and then into the Gulf of Maine from 54 hours to 60 hours.

JFK has received 39.07" precipitation, which is 4.89" above normal for this time of year.

 

Don, do you think such a dual low structure may cause the further offshore low to rob the inner low of moisture and we may dry slot after a few hours of heavy rain?

 

[bluewave]

The 12z NAM is 10 mb deeper than any previous system in SE New England during October.

https://www.wpc.ncep.noaa.gov/research/roth/SLPrecords.html

 

[LibertyBell]

21 minutes ago, Snow88 said:

A lot of rain for the NYC  area and Inland areas. Winds arent strong at all due to the dual structure.

Looks like 2-4 inches of rain and 40 mph gusts?  60 mph in Suffolk County.

 

[LibertyBell]

2 minutes ago, bluewave said:

The 12z NAM is 10 mb deeper than any previous system in SE New England during October.
 

 

Chris, is that 972 low the primary or secondary low?  Looks like the primary low to me, with a secondary developing further offshore.

 

 

[bluewave]

1 hour ago, LibertyBell said:

Chris, is that 972 low the primary or secondary low?

 

It eventually merges with the low just to the west and loops NW into SE New England. The system is so convective, that the models are still struggling with where the best convective blobs and low pressure forms. This one may come right down to the wire.

[Stormlover74]

9 minutes ago, LibertyBell said:

Looks like 2-4 inches of rain and 40 mph gusts?  60 mph in Suffolk County.

 

Wind may be stronger behind the storm especially on Thursday

[purduewx80]

The moisture feeding into this low is in the upper echelon of what we usually see this time of year, supporting the heavy rain threat. The 12Z JAX PWAT climo is below, but LCH and LIX were also impressive.

 

[donsutherland1]

55 minutes ago, LibertyBell said:

Don, do you think such a dual low structure may cause the further offshore low to rob the inner low of moisture and we may dry slot after a few hours of heavy rain?

 

Not in this case. The closer low is forecast to rapidly deepen. In most cases, the offshore low is dominant and/or deepening, pulling the moisture offshore.

[LibertyBell]

5 minutes ago, donsutherland1 said:

Not in this case. The closer low is forecast to rapidly deepen. In most cases, the offshore low is dominant and/or deepening, pulling the moisture offshore.

Wow, this sounds pretty rare- I dont remember something like this happening before.  Has it?  In every case I remember the offshore low takes over.

 

 

[MJO812]

Gfs is further west with the heavier rain.

 

[psv88]

2 hours ago, LibertyBell said:

Both were colder than KFOK!

 

FOK hit 37

[LibertyBell]

12 minutes ago, psv88 said:

FOK hit 37

Thanks- their lowest of the season?

 

[SnoSki14]

So far I see a good consensus of a 2"+ widespread rainfall total with 3"+ isolated spots. 

Would be a nice way to end the dry spell. 

[doncat]

4 hours ago, donsutherland1 said:

The recent dry spell has led to New York City's precipitation having fallen below normal on a year-to-date basis. In addition, the implied probability of New York City's seeing 50" or more precipitation this year has decreased to 45%.

However, there is strong model consensus that the region will likely experience its biggest rainstorm in several months as a strong nor'easter moves across western Long Island into New England. Widespread 1"-2" rainfall amounts with local amounts in excess of 3" appears likely tomorrow into Thursday.

Below is a summary of the precipitation status for select cities:

Similar to EWR  at my station with 46.05" YTD, which is about a +8" departure.

[Brian5671]

euro is much drier for the region...1 inch average 2 inches here and there but isolated