October 2020 General Discussions & Observations Thread

[donsutherland1]

Morning thoughts...

Today will be mostly sunny, breezy and much cooler than yesterday. Temperatures will likely top out in the lower and middle 60s across the region. Likely high temperatures around the region include:

New York City (Central Park): 64°
Newark: 66°
Philadelphia: 67°

Milder conditions will quickly return toward the weekend. Rain from the remnants of Hurricane Delta could impact the region from late Sunday through Tuesday. Details remain to be resolved.

 

[binbisso]

After a warm wet week  next week That's a pretty cold look on the ensembles today starting around day 9 going through the end of their runs. The mjo looks to get Amplified in Phase 4 and Phase 5 around that time and I believe it's a colder phase for the Northeast during October I could be wrong though. Any Merit to a colder second half of October?

[CIK62]

The 12Z GFS for the next 16 days still has 8 days in the 70's upcoming.      A normal high of 70 went out the window with September.        It averages 64degs., from which I would subtract 8 degrees at this range.       So just about Normal for the period sounds reasonable.       BN does not get underway till the 21st.      Maybe it will really start sooner.       The ENS is about 58 for the this period.

[donsutherland1]

2 hours ago, binbisso said:

After a warm wet week  next week That's a pretty cold look on the ensembles today starting around day 9 going through the end of their runs. The mjo looks to get Amplified in Phase 4 and Phase 5 around that time and I believe it's a colder phase for the Northeast during October I could be wrong though. Any Merit to a colder second half of October?

The latest EPS weeklies and the subseasonal guidance favor cooler conditions during the last week or so in October. Whether they continue beyond that, should they develop, remains uncertain.

[donsutherland1]

Despite bright sunshine, the temperature rose only into the lower and middle 60s across the region. After a cool night, a warmup will commence. Readings will likely reach the upper 60s and lower 70s tomorrow.

Afterward, generally above normal temperatures will prevail through mid-month. By mid-month, New York City will likely have an October 1-15 mean temperature above 60° and the region will likely see temperatures running an overall 1°-3° above normal.

Rain associated with the remnants of Hurricane Delta, which will likely make landfall as a Category 2 or perhaps Category 3 hurricane along the Louisiana coast on Friday, will likely impact the region Sunday night through Tuesday. The potential exists for a moderate to possibly significant rainfall in parts of the region. There remains considerable uncertainty.

The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around September 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.82°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely prevail into at least the start of winter.

The SOI was +13.92.

Today, the preliminary Arctic Oscillation (AO) figure was -0.024.

On October 7 the MJO was in Phase 5 at an amplitude of 1.285 (RMM). The October 6-adjusted amplitude was 1.215.

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO.

In addition, from the larger pool of La Niña winters following El Niño winters, there were four cases where October saw the MJO in Phases 4-6 for 20 days or more: 1983-84, 1988-89, 1998-99, and 2016-17. All four cases featured an EPO+/AO+ winter. Three cases saw the MJO in Phases 4-6 for less than 20 days: 1995-96: 12 days, 2007-08: 6 days, and 2010-11: 6 days. Both 1995-96 and 2010-11 featured a predominantly negative AO. The latest ensemble guidance favors October 2020 falling into the former pool. Among that pool, October 1983 and 2016 featured above normal and near normal rainfall respectively. October 1988 and 1998 saw below normal and much below normal rainfall respectively.

Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.5°.  

[SACRUS]

10/8

ACY: 69
New Brnswck: 69
EWR: 68
PHL: 68
JFK: 67
BLM: 67
ISP: 66
TTN: 65
TEB: 65
LGA: 65
NYC: 64

[LibertyBell]

15 hours ago, bluewave said:

It will be interesting to see if Delta slows down enough for both Monday and Tuesday to record at least an inch of rain in NYC. Most of our events in recent years had the heaviest precipitation focused into just 1 day. The last 2 consecutive NYC days with 1.00” plus of precipitation was 1-23/24-17. Getting 2 consecutive days of 2.00”+ has been even tougher. The last time for NYC was with Irene on 8-27/28-11.

Number of Consecutive Days Precipitation >= 1.00 
for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
Last value also occurred in one or more previous years.
Period of record: 2017-01-01 to 2020-10-07
1	2	2017-01-24
2	1	2020-09-30
-	1	2020-09-10
-	1	2020-08-12
-	1	2020-07-22
-	1	2020-07-10
-	1	2020-04-13
-	1	2020-03-23
-	1	2019-12-14
-	1	2019-12-09

 

Number of Consecutive Days Precipitation >= 2.00 
for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
Last value also occurred in one or more previous years.
Period of record: 2011-01-01 to 2020-10-07
1	2	2011-08-28
2	1	2020-07-10
-	1	2018-08-11
-	1	2018-07-17
-	1	2018-04-16
-	1	2017-10-29
-	1	2017-05-05
-	1	2016-11-29
-	1	2016-01-23
-	1	2015-01-18

Chris, when was the last time NYC has had 1.0" of LE (all snow) in two consecutive days?

 

[CIK62]

The next 8 days are averaging 61degs.     Making it 56degs., or -3.0.

54*(56%RH) here at 6am.       55* at 7am.       60* by 11am.       64* by 2pm.      65* at 3pm.       67* at 4pm.         70* around 5pm.        65* by 8m.      62* by 10pm.

Tropics:   26.7N  93.9W.     LA. coast already getting 30mph + winds.   Eye should cross LA coastline near 92.5W(going to be closer to 92.8W) around 8pm this evening with 80mph+ winds still possible.      28.6N  93.6W by 4pm.

We should get 2"-3" during late Sunday to Thursday AM.       All models in on this.

NW NJ---32* and a bit of white near Oct. 22?

[tim]

...KFOK @ 34*

Eastport @ 42*..

[wdrag]

No topic yet for late Sunday-Wed night. Too much variability and NAEFS probs for 2+ diminished a bit since yesterday. WPC also cut back a little.

Lots of potential though and can see general 1-2" spotty 4.5" by Tuesday evening with beyond uncertainty but further qpf possible Wed and even Thursday. PWAT/instability burst late Sunday-Monday morning and then PWAT near 2" late Monday-Tuesday morning. Even could be isolated thunder. With a big cool high to the northeast, could see G 35KT near LI.  

For now, waiting it out to see if the GEFS comes back closer to the EPS for late Sun-Tuesday.  

Models have slowed a bit so Sunday afternoon-evening is a little in doubt. 

Overall, for myself, just don't want to topic what could still be only a routine event.  

[donsutherland1]

Morning thoughts...

At 7 am, temperatures included: Allentown: 40°; Islip: 48°; New York City: 53°; Newark: 50°; Philadelphia: 50°; Poughkeepsie: 37°; Westhampton: 36°; and, White Plains: 48°.

After a cool start, a warmer afternoon is in store. Temperatures will likely top out in the upper 60s and lower 70s across the region. Likely high temperatures around the region include:

New York City (Central Park): 68°

Newark: 71°

Philadelphia: 71°

Rain from the remnants of Hurricane Delta will likely impact the region from late Sunday through Tuesday. 

[lee59]

42 degree low here this morning.

[bluewave]

8 hours ago, LibertyBell said:

Chris, when was the last time NYC has had 1.0" of LE (all snow) in two consecutive days?

 

2-25/26-10 came the closest. NYC got the 2 consecutive LE days over 1.00” but missed the 10” of snow on the 1st day by .6.

2010-02-25	38	27	32.5	-4.7	32	0	2.00	9.4	0
2010-02-26	33	26	29.5	-7.9	35	0	1.17	11.5	14

[uncle W]

9 hours ago, LibertyBell said:

Chris, when was the last time NYC has had 1.0" of LE (all snow) in two consecutive days?

 

I don't think NYC had two consecutive days with 1.00" LE from all snow...It did have three consecutive days with at least 1" LE on 2/4-6/1920 from snow, sleet and freezing rain...

[SnoSki14]

14 hours ago, bluewave said:

The Western Ridge and Upper Midwest Trough continues to be the dominant fall pattern. Notice how the height falls near the Pacific Northwest this coming week don’t last. Another big rebound of that ridge in the 6-10 day and potentially beyond. 
 

That would definitely be a lot more favorable for winter than last year.

I think something like 2016-2017 is possible.

[uncle W]

I think the record for consecutive days with at least 1" of rain was when NYC got four straight from 9/23-26/1975...

[bluewave]

2-8/9-13 came close for ISP on the LE and it got the 2 consecutive days of 10”+.

2013-02-08	36	25	30.5	-1.2	34	0	2.21	16.7	0
2013-02-09	29	20	24.5	-7.3	40	0	0.74	11.1	25

 

[jm1220]

3 hours ago, bluewave said:

2-8/9-13 came close for ISP on the LE and it got the 2 consecutive days of 10”+.

2013-02-08	36	25	30.5	-1.2	34	0	2.21	16.7	0
2013-02-09	29	20	24.5	-7.3	40	0	0.74	11.1	25

 

I’m seeing 12-13 pop up as an analog in some places and it would be fine for me. Where I am now probably had close to 2 feet from the 2/8-9 event. 

[LibertyBell]

5 hours ago, bluewave said:

2-25/26-10 came the closest. NYC got the 2 consecutive LE days over 1.00” but missed the 10” of snow on the 1st day by .6.

2010-02-25	38	27	32.5	-4.7	32	0	2.00	9.4	0
2010-02-26	33	26	29.5	-7.9	35	0	1.17	11.5	14

at JFK and SW Nassau we had an inch of rain followed by double digit snow, first time ever for that lol

[LibertyBell]

3 hours ago, uncle W said:

I think the record for consecutive days with at least 1" of rain was when NYC got four straight from 9/23-26/1975...

wow was that a stalled noreaster?

how did we do in Dec 1991?

[LibertyBell]

4 hours ago, uncle W said:

I don't think NYC had two consecutive days with 1.00" LE from all snow...It did have three consecutive days with at least 1" LE on 2/4-6/1920 from snow, sleet and freezing rain...

our w.e. champ for winter storms lol, all snow that would have been 50"....

was it below freezing for that entire storm here?

 

[bluewave]

18 minutes ago, LibertyBell said:

at JFK and SW Nassau we had an inch of rain followed by double digit snow, first time ever for that lol

I wonder if a specific cause can be found for the record -NAO /-AO from June 2009 through January 2011?Somebody should do a research study on that. You know something unusual was underway when it started with such cool weather for June and July. 
 

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

Rank	Ending Date	Mean Avg Temperature Jun 1 to Jul 31	Missing Count
1	1881-07-31	69.4	0
2	1903-07-31	70.0	0
3	2009-07-31	70.1	0
4	1902-07-31	70.3	0
5	1914-07-31	70.5	0

[wdrag]

Looking back to the first week of October which the NAEFS modeled odds favoring colder than normal. NOT here at our longitude eastward in the forum. No freezes, no snow in the Ads-Catskills, no coldest day of the season.  The verification was very good in Ohio Valley-Great Lakes to the Apps. We ended up in the bad forecast zone (too cool). Here it is...

 

[MJO812]

Rain coming next week

[bluewave]

1 hour ago, wdrag said:

Looking back to the first week of October which the NAEFS modeled odds favoring colder than normal. NOT here at our longitude eastward in the forum. No freezes, no snow in the Ads-Catskills, no coldest day of the season.  The verification was very good in Ohio Valley-Great Lakes to the Apps. We ended up in the bad forecast zone (too cool). Here it is...

 

Seems like the Western Atlantic Ridge often finds a way to beat guidance with such warm SSTs off the coast.

 

 

[wdrag]

Barring a significant drying out of the operational00z/10  NAM/GFS/EC/ICON/GGEM, will probably start a topic tomorrow morning for the period 2PM Sunday-2PM Tuesday of a 1-3" rain event and chance of a tiny area of 4.5" w possible gale gusts vicinity LI-Sandy Hook.  More details tomorrow morning (upon further review as they say).  I've added the 36 hour chance of 3+" of rain from the SREF...it is decidedly beefier than the GFS...so it's heavier forecast is not a lock.  You'll view th'e chance of 3"+ using the legend comparison,  ending at  11PM Monday (which might be most of the event?), save for less than 1/2" additional of drizzle-rain after 11 PM Monday through Noon Tuesday.  Also the bottom panel has the average of the SREF members. 

[wdrag]

In case you notice a little haziness to the sky this eve, or tomorrow morning, it's smoke from the western USA.  Here is a sample modeled position of the plume tomorrow morning around sunrise when it may be a little more prominent overhead of the  I95 corridor. 

 

[hudsonvalley21]

[donsutherland1]

Today was a mild October day with temperatures reaching the upper 60s and lower 70s. Tomorrow will be even warmer with highs topping out in the middle 70s in many parts of the region.

Generally above normal temperatures will prevail through mid-month. By mid-month, New York City will likely have an October 1-15 mean temperature above 60° and the region will likely see temperatures running an overall 1°-3° above normal. Afterward, a period of cooler than normal to near normal temperatures could develop.

Rain associated with the remnants of Hurricane Delta, which made landfall near Creole, Louisiana with maximum sustained winds of 100 mph early this evening, will likely impact the region Sunday night through Tuesday. The potential exists for a moderate to significant rainfall in parts of the region. There remains uncertainty about rainfall amounts.

The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around September 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.82°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely prevail into at least the start of winter.

The SOI was +19.53.

Today, the preliminary Arctic Oscillation (AO) figure was -0.600.

On October 8 the MJO was in Phase 5 at an amplitude of 1.510 (RMM). The October 7-adjusted amplitude was 1.295.

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO.

In addition, from the larger pool of La Niña winters following El Niño winters, there were four cases where October saw the MJO in Phases 4-6 for 20 days or more: 1983-84, 1988-89, 1998-99, and 2016-17. All four cases featured an EPO+/AO+ winter. Three cases saw the MJO in Phases 4-6 for less than 20 days: 1995-96: 12 days, 2007-08: 6 days, and 2010-11: 6 days. Both 1995-96 and 2010-11 featured a predominantly negative AO. The latest ensemble guidance favors October 2020 falling into the former pool. Among that pool, October 1983 and 2016 featured above normal and near normal rainfall respectively. October 1988 and 1998 saw below normal and much below normal rainfall respectively.

Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.5°.  

[jm1220]

Could be a very nice rain event if we get the slug of moisture left from Delta along with focusing from a frontal boundary nearby. NAM has been pretty insistent on up to 4" of rain near that boundary over a fairly prolonged period. Hopefully it can extend N into New England where there's a severe drought.