September 2020 wx discussion

[LibertyBell]

On 9/23/2020 at 11:10 AM, lee59 said:

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.

One thing that's really weird is that both the west and the northeast have been very dry this year.....it isn't just CA and OR that are in severe drought, so is RI......some interesting numbers.....

Medford has gone 100 days without measurable rain in Oregon.

Las Vegas has gone 156 days without measurable rain

Both of the above are records.

Hartford has only had 21 inches of rain so far this year, their 3rd driest on record.

Concord, NH has only had 18 inches of rain so far this year, their 8th driest on record.

 

Meanwhile the Southeast has been consistently flooded out right from the start of the year.

 

[CIK62]

The last 6 days of September are averaging 73degs.     Making it 69degs., or +3.5.

Month to date is  -0.7[68.4].         September should end at 68.5, or near Normal.

With the long range +5 to +8 ( or more) GFS bias, we should be due some lows in the the 40's during the first 10 days of October.

64*(86%RH) here at 6am, heavy haze.    63* at 7am.       T again went nowhere around here, topping out at 74*, now 69*(90%RH)at 8pm.

[LibertyBell]

17 hours ago, bluewave said:

Looks to max out from 4 to 5 sd around Alaska and also Greenland. 
 

 

 

Speaking of Greenland, did you see that the WMO finally recognized that -93.3 temp at Klinck, Greenland from 12/22/91 as the coldest ever recorded in the Northern Hemisphere?  Personally I feel that Summit Camp is colder, but they've only kept records for a few years there at the top of the ice cap on Greenland.  It's colder than the coldest parts of Siberia though, but doesn't get anywhere near as warm in the summer.

 

 

[bluewave]

18 minutes ago, LibertyBell said:

Speaking of Greenland, did you see that the WMO finally recognized that -93.3 temp at Klinck, Greenland from 12/22/91 as the coldest ever recorded in the Northern Hemisphere?  Personally I feel that Summit Camp is colder, but they've only kept records for a few years there at the top of the ice cap on Greenland.  It's colder than the coldest parts of Siberia though, but doesn't get anywhere near as warm in the summer.

 

 

Yeah, I saw that. The early 90s were colder times combined with the strong +AO and PV. We actually surpassed those records last JFM. A new paper mentions that the IO standing wave may have contributed. Similar to another paper that I posted last winter. So we need to look to the Indian Ocean for hints on the AO. So some of the long range +AO forecasts for last winter worked out very well. But it verified much stronger than they indicated.

https://www.essoar.org/pdfjs/10.1002/essoar.10503356.1

P

 

Positive SST anomalies in the Indian Ocean have

[LibertyBell]

8 minutes ago, bluewave said:

Yeah, I saw that. The early 90s were colder times combined with the strong +AO and PV. We actually surpassed those records last JFM. A new paper mentions that the IO standing wave may have contributed. Similar to another paper that I posted last winter. So we need to look to the Indian Ocean for hints on the AO. So some of the long range +AO forecasts for last winter worked out very well. But it verified much stronger than they indicated.

https://www.essoar.org/pdfjs/10.1002/essoar.10503356.1

P

 

Positive SST anomalies in the Indian Ocean have

Chris, I remember there was a streak in 1990 and 1991 where 22 out of 24 months were above normal.  That was just an appetizer for our current climate.....

 

[bluewave]

1 minute ago, LibertyBell said:

Chris, I remember there was a streak in 1990 and 1991 where 22 out of 24 months were above normal.  That was just an appetizer for our current climate.....

 

Montana was one of the few spots not to see as many above normal months.

 

[SACRUS]

 

58/58 here foggy/misty and clouds above the fog.  Looks mostly clouds through early afternoon before we can see some sun around 1PM.  With enough sun it should poke into the upper 70s perhaps low 80s.  Warm again tomorrow and partly to mostly cloudy but little if any rain. 

Sun - Tue with enough sunshine and 850 MB temops >15C will see max temps in mid perhaps an upper 80 in the warm spots but clouds look plentiful with night time lows in the 60s perhaps a 70 spread in between in LGA/JFK / upper 60s NYC/EWR. 

Front comes through at some point Tue (9/29) and Wed (9/30).  Cooler 10/1 - 10/6 but again not likely as cold as this past period 19th - 23rd.  Brunt of cold is west of the region into the Plains, GL and OV down into the Mississippi valley.  A piece of the deeper cool does look to come through Oct 4 - 6th in a moderated fashion.  West cast ridge looks to break down even if for a period by Oct 7th with warmer times in store.  Way beyond does ridge relocate or rebuild in the west?

9/25 - 9/30 : Much warmer than normal mainly drier.  Max temps Sun (9/26) - Tue (9/29).

10/1 - 10/6:   Cooler to much cooler (10/4 - 10/6).  Still think the coldest stays west of the area. Rain chances 10/1-10/2 with reinforced front/ trough moving through.

 

 

[donsutherland1]

Morning thoughts...

Today will be partly sunny and warm. The temperature will likely top out mainly in the upper 70s with a few lower 80s across the region. Likely high temperatures around the region include:

New York City (Central Park): 78°
Newark: 80°
Philadelphia: 78°

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

Yesterday was Las Vegas' 157th consecutive day with no measurable precipitation. That is the longest such stretch on record for that city.

 

[bluewave]

We are on track to set a new September monthly 500 mb positive height record for the West Coast. A new daily record was set earlier this month. This would surpass the previous September monthly record set in 2012.

 

 

[MJO812]

Models getting wetter for next week

[Brian5671]

28 minutes ago, MJO812 said:

Models getting wetter for next week

Best still west of us as the front gets hung up, but I'll take what I can get it's bone dry here after 2 weeks of sun and low humidity

[bluewave]

27 minutes ago, Brian5671 said:

Best still west of us as the front gets hung up, but I'll take what I can get it's bone dry here after 2 weeks of sun and low humidity

 

The New England crew is probably happy that this is a rainfall departure and not snowfall.

 

[MJO812]

Euro looks wet for next week 

[rclab]

4 hours ago, bluewave said:

The New England crew is probably happy that this is a rainfall departure and not snowfall.

 

From what I’ve read in the New England forum, their is a growing concern for the droughts effects on the flora and the potential for fire. Your fine graphic underlines their fears. As always.....

[bluewave]

20 minutes ago, rclab said:

From what I’ve read in the New England forum, their is a growing concern for the droughts effects on the flora and the potential for fire. Your fine graphic underlines their fears. As always.....

Maybe the wetter Euro and UKMET further east will work out for them. I guess it comes down to how much of a phase we get between the two pieces of energy. 

[doncat]

4 hours ago, bluewave said:

The New England crew is probably happy that this is a rainfall departure and not snowfall.

 

If you want to go further back...If my math is correct, Hartford has had 6.98" of rain since May 1st...My station for comparison has had 18.65".

[donsutherland1]

Tomorrow will be mainly cloudy with perhaps a few showers and a little cooler than today. In general, temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is possible in the opening week of October, but warmer readings could return during the following week.

Phoenix has an implied 90% 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 near 95.3°. That would exceed the previous June-August record of 95.1°, which was set in 2013 and tied in 2015. 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 +16.88.

Today, the preliminary Arctic Oscillation (AO) figure was +0.613.

On September 24, the MJO was in Phase 5 at an amplitude of 1.436 (RMM). The September 23-adjusted amplitude was 1.370.

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 79% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.6°.

 

[SACRUS]

9/25

LGA: 80
EWR: 80
TEB: 79
New Brnswck: 78
NYC: 77
BLM: 77
TTN: 76
ISP: 76
PHL: 75
JFK: 75
ACY: 73

[Rtd208]

The 0z GFS now shows a low developing along the coast mid to late next week enhancing the rainfall similar to what the Euro has been showing.

[MJO812]

1 hour ago, Rtd208 said:

The 0z GFS now shows a low developing along the coast mid to late next week enhancing the rainfall similar to what the Euro has been showing.

 

[bluewave]

12 hours ago, doncat said:

If you want to go further back...If my math is correct, Hartford has had 6.98" of rain since May 1st...My station for comparison has had 18.65".

This was their driest ever 05-01 to 9-25.

Time Series Summary for Hartford Area, CT (ThreadEx)
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Total Precipitation May 1 to Sep 25	Missing Count
1	2020-09-25	6.98	0
2	1964-09-25	8.35	0
3	1957-09-25	8.82	0
4	1965-09-25	9.45	0
5	1914-09-25	10.79	0

 

[CIK62]

The last 5 days of September are averaging 75degs.        Making it 71degs., or +5.5.

Month to date is -0.4[68.5].       September should end at 68.9, approaching +1.0.

GFS back with the tropical system, Oct. 08-10.        6" of rain, including a period of 3" in just 6hrs. here on Oct. 10 AM.      Wind gusts +50mph.       This forecast has the validity/lifespan? of an ice cube in Death Valley during a July day.

66*(88%RH) here at 6am., scattered cloud cover.    70*(80%RH) by 10am.      75* by 3pm.      70* by 11pm.

[Rtd208]

[wdrag]

Good Saturday morning all, Lot's to speculate upon  in two threads. 

Smoke aloft shifts mostly north of our forum today-tomorrow. Meanwhile fire danger increases in CA next week per big ridge aloft out west with SPC outlining D3-4 out there, even as fire danger in shorter term near the Rockies has resulted in a new plume out of southern WY. 

No topic yet on previously posted qpf graphics for Mon-Wed night  but potential exists for pockets 4+. If that occurs over high density related infrastructure then iso flood problems.  Just too early but potential exists per modeled QPF max's. 

Oct 1-10 in the Oct section. 

[donsutherland1]

Morning thoughts...

At 8:45 am, a shrinking area of moderate to heavy rain that had brought 0.66" rain to Wilmington was headed northward toward Allentown. Much of the rest of the region was cloudy with a few widely scattered light showers. Today will be mainly cloudy with perhaps a few additional showers. The sun could begin to break through the clouds during the afternoon. Temperatures will likely reach the lower to perhaps middle 70s across the region. Likely high temperatures around the region include:

New York City (Central Park): 74°
Newark: 75°
Philadelphia: 75°

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

 

[bluewave]

Cool departures should turn warm as we continue the warmer September pattern.

 

[gravitylover]

20 hours ago, bluewave said:

The New England crew is probably happy that this is a rainfall departure and not snowfall.

 

Run that with 5/27 as the start date. The departure in SE NY should be much more significant.

[SACRUS]

71/60, mostly cloudy with some breaks of sun, mainly east and showers to the west in WNJ and EPA.  More clouds and some breaks of sun today will make it tough to crack 80 unless some spots see longer stretches of sun (could happen like it did yesterday in EWR/LGA).  Sunday -  less showers but some lingering clouds and dew points coming up more, highs again in the mid 70s to low 80s in the warmer sunnier spots.  More of the same Mon and Tue  but with any longer breaks of sun we can see sneaky low to mid 80s.  Brunt of the cool stays west through this period as trough dings down the plains and GL into the south.

Rain followed by cool.  Front will crawl along the east cost Tue - Thu with a wave of low pressure riding up through the areas on Thu (10/1) could see heaviest rain since Sep 11th.  Beyond that cooler air flows in 10/2 - 10/6.  Coldest temps likely 10/4 - 10/6 before we warm up by 10/7 and into the second week of the month.  West coast ridge does look to want to rebuild, need to watch but trough looks poised to stay into the plains/ GL, warmer along the coast.  Way beyond WC ridge should get displaced east to close the last 1/3 of the month.

9/26 - 9/30: Warmer than normal, minimal rain, max low 80s warm minimums +5 to +7 above normal

9/30 - 10/1: Rain >inch  possible (first time since 9/11).

10/2 - 10/6 : cooler than normal, inland frost 10/5 - 10/6?

10/7 : warming up

 

 

[uncle W]

if you go by real averages September averaged 68.3 from 1981-2010...so far this September is averaging 68.5 but should end up a little higher when the month ends...it looks like the 1991-2020 average should be 68.9 ...this September will be near the 1991-2020 average...

[MJO812]

64 here in Brooklyn