September 2020 wx discussion

[donsutherland1]

After an unseasonably cool start, a noticeable warmup commenced. Under bright sunshine, the temperature rose into the lower 70s in many parts of the region. High temperatures included:

Allentown: 73°
Baltimore: 73°
Harrisburg: 75°
Islip: 70°
New York City: 71°
Newark: 75°
Philadelphia: 74°
Washington, DC: 73°

Westhampton recorded a daily and monthly record low temperature of 32°. The previous daily record was 37°, which was set in 1962. The previous September record was 33°, which was set on September 24, 1998 and tied on September 29-30, 2000 and September 18, 2013. This was also Westhampton's earliest freeze on record. The prior record was October 2, 1998, which was tied on October 2, 2009. Both cases saw a minimum temperature of 32°.

Afterward, temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is possible to open October.

Phoenix has an implied 83% probability of recording just its 13th September on record with a mean temperature of 90° or above. The most recent such occurrence was 2018 with a mean temperature of 91.8°. Phoenix will very likely record its hottest June-September period on record with a four-month mean temperature of 95.2°-95.4°. The existing record is 93.9°, which was set in 2011.

The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around September 16. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.93°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions have developed and will likely prevail through the remainder of autumn.

The SOI was +12.72.

Today, the preliminary Arctic Oscillation (AO) figure was +2.183.

On September 21, the MJO was in Phase 5 at an amplitude of 0.999 (RMM). The September 20-adjusted amplitude was 0.878.

Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°.

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.   

Based on sensitivity analysis applied to the latest guidance, there is an implied 61% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.4°.

 

[SACRUS]

9/22

EWR: 75
LGA: 74
JFK: 74
New Brnswck: 74
PHL: 74
BLM: 73
ACY: 73
TEB: 73
TTN: 72
NYC: 71
ISP: 70

[SACRUS]

4 hours ago, LibertyBell said:

Colder than the weather we just went through, Walt?

30 degrees this morning at MPO

 

ECM has similar type cold on 12z guidance while prior runs and ensembles keep the brunt of the cold to the west in the 0ct 1 - oct 5th period with maybe a day of the real chilly air coming in.

[CIK62]

Reached 73* here.      Might try a late season trip to the beach here if winds are light tomorrow.        Today's gusts stired up a brush/debris fire at Bay 44th. St. and the BP.

As hinted to by the EURO with its favorable BN pressures along EC and back to the eastern GOM we have this:

[jm1220]

7 hours ago, MJO812 said:

Teddy looks really nice

If only this was further west

No. Just no. 

Moon looks orange/reddish tonight, wildfires smoke? 

[bluewave]

This was the 10th coldest 9-16 to 9-22 in NYC. It was also the coldest since 1993.

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 Sep 16 to Sep 22	Missing Count
1	1875-09-22	54.7	0
2	1871-09-22	55.8	0
3	1990-09-22	59.5	0
4	1929-09-22	59.6	0
5	1956-09-22	59.7	0
6	1993-09-22	59.8	0
7	1962-09-22	60.3	0
8	1879-09-22	60.4	0
9	1873-09-22	60.7	0
10	2020-09-22	60.9	0

[CIK62]

The last 8 days of September are averaging 74degs.       Make it 69degs., or +3.5.

Month to date is -1.0[68.4].      September should end at +0.6[68.6].

The Tropics:   43.9N 62.9W-Teddy turns into Nova Scotia Lox within hours.

60*(51%RH) here at 6am, m. clear.   59* at 6:30am.    68* by 11am.      71* by Noon.       73* at 1pm, equal to yesterday's high here but rather breezy again.

80* by 4pm.

[SnoSki14]

EPS/GEFS continue to signal strong cool down 1st week of Oct with possibly some rains.

[bluewave]

5 minutes ago, SnoSki14 said:

EPS/GEFS continue to signal strong cool down 1st week of Oct with possibly some rains.

The record Western Ridge just won’t let up.

 

[wdrag]

14 hours ago, LibertyBell said:

Colder than the weather we just went through, Walt?

30 degrees this morning at MPO

 

Cant promise colder but it seems the 850 temps cold be colder...if its a mixed environment or LE clouds or offshore storm passages, then the clouds keep the mins up.  I kind of think this pattern has a killing freeze in it for the suburbs (1 night) but I could be overdoing it.  It seems 850 temps and sfc temps in the Ohio Valley will be 5 to 10 below normal and I think that at least one day should be colder than any to date in NYC this Sept.

[lee59]

47 degrees this morning, fifth morning in a row in the 40s

[wdrag]

Following up: This is really for the first week of October.  NAEFS prob of a colder than normal start to the month (Not the whole month-first week should be colder than normal but this doesn't say anything about the last two weeks of the month). The trough in the east seems to live beyond the 8th.  Also added the chance of 2" of rain in that same period (second slide) and finally the chance of 4 tenths of an inch.  

As you can see the bullish 00z/23 op GFS on a storm up the east coast the first week of October is  NAEFS ensembled  well to the east of the East Coast. However, the coldest weather of the season may occur this first week of October, including a smidge of snow in the Adirondacks or Catskills and a chance of a killing freeze in the interior suburbs "if" we get 1 cloud free light wind night. Daytime highs have a better chance of being the coolest of the season for 1 or 2 days in this period. 

Finally... I don't like this pattern for the sw USA fire danger..as posted just  bit earlier by blue wave... very strong ridge in CA next week... could be setting up for increased fire danger there. Need to follow the sw USA topics - NWS guidance on this.  Already in the short term... WY has increased fire danger by the NWS. 658A/23

 

[donsutherland1]

Morning thoughts...

Much warmer weather has returned. Today will be mostly sunny and unseasonably warm. The temperature will likely top out mainly in the upper 70s and lower 80s across the region. Likely high temperatures around the region include:

New York City (Central Park): 79°
Newark: 82°
Philadelphia: 81°

The temperature will likely remain above normal through the remainder of this week.

 

[uofmiami]

44.5 in Muttontown & 45.5 in Syosset for morning lows. 

[lee59]

The Atlantic, outside of sub tropical storm Teddy moving away, is free of any tropical systems. I believe the U.S. mainland has had 4 hurricanes this season and 1 of them was a major. The season is now on the decline (but certainly not over) as we are now approaching cooler weather. I think wind shear really kept a lid on a lot of storms this season.

[SnoSki14]

1 hour ago, bluewave said:

The record Western Ridge just won’t let up.

 

Awful given the fires there.

[uofmiami]

18 minutes ago, lee59 said:

The Atlantic, outside of sub tropical storm Teddy moving away, is free of any tropical systems. I believe the U.S. mainland has had 4 hurricanes this season and 1 of them was a major. The season is now on the decline (but certainly not over) as we are now approaching cooler weather. I think wind shear really kept a lid on a lot of storms this season.

Time to watch the W Caribbean area:

 

[the_other_guy]

1 hour ago, SnoSki14 said:

Awful given the fires there.

Yes.

 

Could be good for us if it continues to winter thru winter.

We havent seen this prolonged pattern in a while

 

 

 

[lee59]

1 hour ago, SnoSki14 said:

Awful given the fires there.

Every year these fires cause such devastation. There is little doubt that climate change has helped fuel the fires but the real problem is people. Some 80 to 90 per cent of these fires are started by people, the rest by lightning. Maybe we need more education on fire prevention, (I remember always seeing the "smoky the bear" commercials), and better forest management, now that so many more folks live in these fire prone areas.

[SnoSki14]

8 minutes ago, lee59 said:

Every year these fires cause such devastation. There is little doubt that climate change has helped fuel the fires but the real problem is people. Some 80 to 90 per cent of these fires are started by people, the rest by lightning. Maybe we need more education on fire prevention, (I remember always seeing the "smoky the bear" commercials), and better forest management, now that so many more folks live in these fire prone areas.

A lot of the current fires were caused by lightning. 

Sure we could educate people more and clean up the forests but that's not gonna stop these fires from happening.

The only thing that'll stop them is immediately addressing the climate change problem.

[SACRUS]

 

66/48 off a low of 44.  On the way to 80(+) for the first time since Sep 10th.  Warmer times ahead the next 6 days before we cool down to end the month.  Weekend - would keep an eye to see if any rains get here and if clouds linger Saturday, otherwise warm and dry.  Sun (9/27) and Mon (9/28) sneaky warm ahead of the front which looks to come by Tuesday 9/29.  Cooler air 9/30 - 10/5.  Jury still out on the brunt of the cool and if we see it for more than a day or so but think we are not as cool as this past airmass.  Warmer times beyond 10/6 with west coast ridging breaking down and heights coming up into the east.  Have to see if models are right and this change is sustained.

9/23 - 9/30 : dry and warmer than normal warmest days (9/23, 9/25, 9/27)

10/1  - 10/6 : Cooler than normal coldest days  (10/3 - 10/5)

[psv88]

46 minutes ago, lee59 said:

Every year these fires cause such devastation. There is little doubt that climate change has helped fuel the fires but the real problem is people. Some 80 to 90 per cent of these fires are started by people, the rest by lightning. Maybe we need more education on fire prevention, (I remember always seeing the "smoky the bear" commercials), and better forest management, now that so many more folks live in these fire prone areas.

People are causing climate change...

[lee59]

41 minutes ago, SnoSki14 said:

A lot of the current fires were caused by lightning. 

Sure we could educate people more and clean up the forests but that's not gonna stop these fires from happening.

The only thing that'll stop them is immediately addressing the climate change problem.

There is no doubt we have to address climate change but unfortunately that takes years. It is a fact that almost 90%  of these fires are started by people. So if you really want to make headroads in stopping these fires, people simply have to be more careful or make sure the area you live in is not so fire prone by taking whatever actions have to be taken thru managing the forests. The other solution is keep the population down in areas that burn easily.

[lee59]

10 minutes ago, psv88 said:

People are causing climate change...

The problem is to stop climate change immediately, we will have to completely change our life style and most people are not willing. Even if the climate was not changing, if 90% of the fires are started by people, you will still have plenty of devastating fires.

[Cfa]

Speaking of wildfires....

Long Island’s Pine Barrens are even more susceptible to drought, it’s become a yearly occurrence, while Jersey’s Pine Barrens are much larger and more susceptible to lightning, either way it’s a disaster waiting to happen. Pines are highly flammable, and the amount of dry brush, fallen trees, and other dead plant material in the understory makes it worse.

[Allsnow]

On 9/22/2020 at 8:49 AM, Brian5671 said:

if that sticks around into winter we'd be in business for cold at least

Would be a nice pattern for east coast storms as the ridge axis is in the Midwest 

[Allsnow]

2 hours ago, bluewave said:

The sample size for La Niña Octobers with a Western Ridge and Eastern Trough is very small. So we will have to see if the strong ridge to start the month persists like it has in September. There was only 1 La Niña year since 1950 with a pattern like this. It was October 1988. The dominant Pacific feature that winter was that the NEPAC ridge extended north into Alaska. Main problem for us in 88-89 was the very strong +NAO. 08-09 had an almost identical Pacific La Niña pattern with a better Atlantic and more snowfall. So maybe a strong ridge out West in October would be hinting that the Pacific Ridge will extend into Alaska.This would be unlike the last 2 winters with the flat La Niña Ridge North of Hawaii.  But we would have to wait and see how the NAO evolves . Still too early to know if any of this pans out. Just something to think about.

 

88-89 I believe was brutally cold but most of the storms hit the mid Atlantic. @uncle W @donsutherland1?

[Stormlover74]

Just now, Allsnow said:

88-89 I believe was brutally cold but most of the storms hit the mid Atlantic. @uncle W @donsutherland1?

Late Feb 89 dumped 2 feet over south Jersey and the delmarva and missed us completely. Forecast was 6 to 10" and not a flake fell

[forkyfork]

1 hour ago, lee59 said:

Every year these fires cause such devastation. There is little doubt that climate change has helped fuel the fires but the real problem is people. Some 80 to 90 per cent of these fires are started by people, the rest by lightning. Maybe we need more education on fire prevention, (I remember always seeing the "smoky the bear" commercials), and better forest management, now that so many more folks live in these fire prone areas.

if people didn't start the fires the naturally caused ones would have spread out of control regardless 

[lee59]

4 minutes ago, forkyfork said:

if people didn't start the fires the naturally caused ones would have spread out of control regardless 

That is very possible and climate change is one reason why. All I am saying is the best way we can prevent them now, is thru forest management and somehow getting people to be more careful. Just like folks moving to coastal areas and therefore hurricane damage and deaths go up from years ago. Now so many more folks are living in the areas out west that were once not being occupied and therefore much more damage and death, unfortunately. Don't get me wrong, we still have to keep doing what we can to stop polluting our waters, land and atmosphere. I am an optimist on that, I think our energy pollutants of today will become mostly obsolete in the not so distant future as batteries, solar, wind etc. become more widespread.