October 2020 General Discussions & Observations Thread

[bluewave]

The forecast details beyond 7 days may be lower skill than usual. It looks like the EPS is struggling with the wavelengths following the big Epsilon ET. So we’ll probably have to wait and see how the late October into early November forecast evolves.

New run

Old run

[LibertyBell]

On 10/19/2020 at 8:06 PM, donsutherland1 said:

Warmer conditions returned today. Temperatures will likely remain mainly above normal through the remainder of the week. One or more days could see much above normal temperatures.

The ENSO Region 1+2 anomaly was -1.2°C and the Region 3.4 anomaly was -1.4°C for the week centered around October 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.85°C and the ENSO Region 3.4 anomaly has averaged -1.10°C. La Niña conditions will likely prevail at least into mid-winter.

The SOI was -6.71.

Today, the preliminary Arctic Oscillation (AO) figure was -1.163.

On October 18 the MJO was in Phase 5 at an amplitude of 2.400 (RMM). The October 17-adjusted amplitude was 2.592.

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.

Moreover, among the former pool, both 1988-89 and 1998-99 saw the MJO in Phase 5 with an amplitude of 2.000 or above as has occurred this year.  Both those winters featured below to much below normal snowfall in the Middle Atlantic and southern New England areas. Select snowfall seasonal snowfall totals were:

1988-89:
Boston: 15.5"
New York City: 8.1"
Philadelphia: 11.2"

1998-99:
Boston: 36.4"
New York City: 12.7"
Philadelphia: 12.5"

None of this is cast in stone. However, this is a plausible scenario should things evolve toward an EPO+/AO+ winter as is suggested on some of the current seasonal guidance.

Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.8°.

Finally, Arctic sea ice extent remained just below 5 million square kilometers on October 18 (JAXA), which further extended 2020's record for the latest such occurrence of Arctic sea ice extent below 5 million square kilometers.

 

I suspect 1998-99 and 2007-08 will be better analogs than 1988-89.

 

[LibertyBell]

3 hours ago, bluewave said:

Temperatures are off to the races away from the marine layer. 

Wrightstown    MOSUNNY   77  66  69 S7  

Scranton       SUNNY     75  59  57 S9   

Hartford       PTSUNNY   73  60  63 SW9   

 

 

I think it hit 80 at Toms River

[LibertyBell]

20 hours ago, donsutherland1 said:

For the most part, average or above. However, in the cases with the larger amounts, the East wound up with below normal snowfall. The sample size is too small to draw conclusions about the East, especially when one considers ENSO.

I remember the 1991 storm quite well!  Some of our TV Long Range prognosticators predicted that getting early heavy snow in MSP was a good thing because those storms would "move east" and give the east coast heavy snows during the heart of winter.  It never happened lol.

[donsutherland1]

36 minutes ago, LibertyBell said:

I suspect 1998-99 and 2007-08 will be better analogs than 1988-89.

 

A lot will depend on how the pattern ultimately evolves. The odds of an EPO+/AO+ pattern have increased.

[uncle W]

41 minutes ago, LibertyBell said:

I suspect 1998-99 and 2007-08 will be better analogs than 1988-89.

 

QBO is different this year...I'm not sure if that means much...

[Oliviajames]

1 hour ago, bluewave said:

The forecast details beyond 7 days may be lower skill than usual. It looks like the EPS is struggling with the wavelengths following the big Epsilon ET. So we’ll probably have to wait and see how the late October into early November forecast evolves.

New run

Old run

Does the low in Arizona screw with the ridge out west and thus not let the trough in the east go further south?  This is just looking at new run. 

[gravitylover]

5 hours ago, Brian5671 said:

sun has busted out here and we're up to 68

I saw 71 in Danbury under a thick cloud cover. 

[donsutherland1]

Clouds broke during the afternoon and unseasonably mild conditions prevailed. Tomorrow, clouds, mist, and fog will give way to sunshine and somewhat warmer conditions. Widespread readings in the lower 70s in much of the region are likely. Temperatures in such cities as Baltimore, Philadelphia, and Washington, DC could rise into middle and upper 70s.

Toward the end of the week, a major early-season snowstorm will usher a near-record to record cold air mass into the Northern Plains. Numerous single-digit low temperatures will be likely on Sunday morning in parts of Montana, North Dakota, South Dakota, and Wyoming. A few locations could even experience subzero low temperatures. However, much of this cold air will likely remain confined well west of the Middle Atlantic and southern New England regions through much of the remainder of this month.

Temperatures will likely remain mainly above normal through the remainder of the week. One or more days could see much above normal temperatures. A brief shot of cooler air could arrive during the weekend. Toward the end of the month, cooler air could begin to spill into the region. November could commence on a cool note.

The ENSO Region 1+2 anomaly was -1.2°C and the Region 3.4 anomaly was -1.4°C for the week centered around October 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.85°C and the ENSO Region 3.4 anomaly has averaged -1.10°C. La Niña conditions will likely prevail at least into mid-winter.

The SOI was +3.61.

Today, the preliminary Arctic Oscillation (AO) figure was -0.305.

On October 20 the MJO was in Phase 5 at an amplitude of 2.313 (RMM). The October 19-adjusted amplitude was 2.389.

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.

From that larger pool of 10 La Niña winters that followed El Niño winters, there were four cases where October saw the MJO in Phases 4-6 for 20 days or more, as was the case this year: 1983-84, 1988-89, 1998-99, and 2016-17. All four cases featured an EPO+/AO+ winter.

Both 1988-89 and 1998-99 saw the MJO in Phase 5 with an amplitude of 2.000 or above as has occurred this year.  Both those winters featured below to much below normal snowfall in the Middle Atlantic and southern New England areas. Select snowfall seasonal snowfall totals were:

1988-89:
Boston: 15.5"
New York City: 8.1"
Philadelphia: 11.2"

1998-99:
Boston: 36.4"
New York City: 12.7"
Philadelphia: 12.5"

None of this is cast in stone. However, this is a plausible scenario should things evolve toward an EPO+/AO+ winter as is suggested on some of the current seasonal guidance.

Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.8°.

 

[bluewave]

33 minutes ago, Oliviajames said:

Does the low in Arizona screw with the ridge out west and thus not let the trough in the east go further south?  This is just looking at new run. 

Adding a cutoff to the mix just adds to potential model error later in the forecast period.

[uncle W]

1 hour ago, uncle W said:

QBO is different this year...I'm not sure if that means much...

if the la nina becomes strong 2007-08 would be a good enso fit...if it becomes stable and stays weak 2016-17 is a good fit...if it gets a little stronger but not that strong 1995-96 would be a good fit...1988 and 1998 already had a strong la nina in progress at this time...

[LibertyBell]

This weather is utter crap.  It's humid and clammy and my allergies are awful tonight.  How is it that we get this kind of weather in late October and November (the most cloudy month around here), but if we get mild weather in January or February we dont get this humid fog crap?

And anyone have any idea when ragweed pollen season might end this year?  I'm hoping it happens before December otherwise I'll be soaking my yard in weed killing chemicals.....

 

[LibertyBell]

45 minutes ago, JoshSnow said:

I love hot and humid But it’s October it should be almost cold. It’s kinda nasty out

I like hot in the summer, not humid.  Hard to breathe air that's thick with water.  My ideal weather is highs in the mid to upper 70s lows in the mid to upper 50s, with clear blue skies, light winds and low humidity, but in the summer I dont mind temps around 100 as long as the humidity is low.  Last year when we hit 95 here with low humidity in early October it was amazing.

 

[CIK62]

The next 8 days are averaging 62degs.       Making it 57degs., or about +3.0.      Little rain on this run, 0Z, for the 384hrs.

64*(97%RH) at 6am, FOG<0.5mile.       66* by 9am, same fog.         67* by Noon, fog lifts to reveal dirty look.    68* by 4pm.

Tropics:    30.6N 61.0W.   Misses Bermuda but 40' seas for Ireland in 6 days.

[Oliviajames]

4 hours ago, LibertyBell said:

This weather is utter crap.  It's humid and clammy and my allergies are awful tonight.  How is it that we get this kind of weather in late October and November (the most cloudy month around here), but if we get mild weather in January or February we dont get this humid fog crap?

And anyone have any idea when ragweed pollen season might end this year?  I'm hoping it happens before December otherwise I'll be soaking my yard in weed killing chemicals.....

 

If you get mild in January you get cloudy foggy crap.  The only way we get sunny days in January is with cold Canadian high pressures. Warm winters equal dreary days 

[wdrag]

Mostly cloudy and mild through Saturday with drizzle fog overnights-mornings, again next Monday-Wednesday with periods of rain with potential 1-3" of rain IF repeat episodes of rain overlap---that is an unknown but pattern favors a quasi stationary boundary around here early next week as I view the model guidance along with pretty high PWAT of 1.5" or greater. 

In the meantime: Epsilon has made a name for itself and we should see pretty good swell along our Atlantic shores Friday, 6-7'. 

[bluewave]

Starting the day with the low temperatures close to +20. We are right around record warm minimums for the date. 

Newark....currently 65°..avg....46°....+19....record min...64°...

 

 

[LibertyBell]

52 minutes ago, Oliviajames said:

If you get mild in January you get cloudy foggy crap.  The only way we get sunny days in January is with cold Canadian high pressures. Warm winters equal dreary days 

I know like last year, we sometimes get rain during January thaws, but it's rare to have a night full of fog like this.

 

[LibertyBell]

32 minutes ago, bluewave said:

Starting the day with the low temperatures close to +20. We are right around record warm minimums for the date. Some hints that we could get more breaks of sun than yesterday.

Newark....currently 65°..avg....46°....+19....record min...64°...

like late summer with longer nights and more water vapor pollution

[donsutherland1]

Morning thoughts...

Clouds, fog and mist will give way to partial sunshine in much of the region. It will be unseasonably warm with readings in the 70s in much of the region. Likely high temperatures around the region include:

New York City (Central Park): 73°

Newark: 76°

Philadelphia: 79°

Overall, warmer than normal conditions should prevail into the start of the weekend.

[Great Snow 1717]

12 minutes ago, donsutherland1 said:

Morning thoughts...

Clouds, fog and mist will give way to partial sunshine in much of the region. It will be unseasonably warm with readings in the 70s in much of the region. Likely high temperatures around the region include:

New York City (Central Park): 73°

Newark: 76°

Philadelphia: 79°

Overall, warmer than normal conditions should prevail into the start of the weekend.

Can already see the early stages of the winter pattern. 

[LoboLeader1]

13 hours ago, donsutherland1 said:

A lot will depend on how the pattern ultimately evolves. The odds of an EPO+/AO+ pattern have increased.

I have not used my snow blower the past 2 winters, IF those odds of an EPO+/AO+ pattern do increase, it's possible it could be 3 straight winters. Time will tell.

[donsutherland1]

1 minute ago, LoboLeader1 said:

I have not used my snow blower the past 2 winters, IF those odds of an EPO+/AO+ pattern do increase, it's possible it could be 3 straight winters. Time will tell.

Hopefully, that won’t be the case. But things are looking worse than they were a few weeks ago.

[LoboLeader1]

6 hours ago, JoshSnow said:

I love hot and humid But it’s October it should be almost cold. It’s kinda nasty out

I had to turn on the C/A yesterday, due to the humid conditions. Fog was horrible this AM.

[donsutherland1]

6 minutes ago, Great Snow 1717 said:

Can already see the early stages of the winter pattern. 

Many La Niña winters have a lot of warmth, so a warm winter is certainly on the table.

[Great Snow 1717]

1 minute ago, donsutherland1 said:

Many La Niña winters have a lot of warmth, so a warm winter is certainly on the table.

And you are correct about things looking worse than a few weeks ago. 

[KEITH L.I]

36 minutes ago, Great Snow 1717 said:

Can already see the early stages of the winter pattern. 

And if was cold today and this week,would that mean we are headed for a snowy winter? Long range forecasting is still a coin flip.2 months from now things  could be different.There have been warm falls that lead to cold winters.There have been cold falls that lead to mild winters.

[jm1220]

40 minutes ago, LoboLeader1 said:

I have not used my snow blower the past 2 winters, IF those odds of an EPO+/AO+ pattern do increase, it's possible it could be 3 straight winters. Time will tell.

We’re overdue for a lousy stretch of winters, and the Nina background state in general is lousy for this area. We’ve gotten used to being spoiled. Our one real hope IMO is the NAO developing blocking every once in a while which can keep the SE ridge in check, and that happening in Dec. If we don’t see that the SE ridge dominates and we see constant lake cutters. If we make it to normal snow somehow this season I’d consider that a big win. Should be a huge winter for the upper Midwest, Rockies and NNE. 

[Great Snow 1717]

Just now, KEITH L.I said:

And if was cold today and this week,would that mean we are headed for a snowy winter? Long range forecasting is still a coin flip.2 months from now things  could be different.There have been warm falls that lead to cold winters.There have been cold falls that lead to mild winters.

Last 5 years, how many cool/cold months has there been???  

[Great Snow 1717]

1 minute ago, jm1220 said:

We’re overdue for a lousy stretch of winters. We’ve gotten used to being spoiled. Our one real hope IMO is the NAO developing blocking every once in a while which can keep the SE ridge in check, and that happening in Dec. If we don’t see that the SE ridge dominates and we see constant lake cutters. If we make it to normal snow somehow this season I’d consider that a big win. Should be a huge winter for the upper Midwest, Rockies and NNE. 

A normal winter would be a big win.