September 2020 wx discussion

[bluewave]

1 hour ago, donsutherland1 said:

When the IOD is positive, the MJO is often in more favorable phases. However, long-term changes in sea surface temperatures are promoting an increased tendency for the MJO to reside in the Maritime Continent.

Here's a paper @bluewave posted on this topic: https://www.nature.com/articles/s41586-019-1764-4

 

Yeah, those warming WPAC SSTs lead to the record MJO 4-6 activity during recent winters. This served to enhance the La Niña background state over the last 4 winters. It resulted in mild to record warm winters with the SE Ridge dominating and setting a new record in February 2018. But the location of the NPAC ridge made the difference between snowy and nearly snowless winter outcomes. 2017 to 2018 featured the ridge near the Aluetians and more NATL blocking with a snowy pattern. During the 2019 to 2020 period ,the ridge was much flatter near Hawaii. So we got the two recent nearly snowless DJF periods along with a strong NATL PV. While it looks like we could experience a 5th La Niña background state winter, we’ll have to see how the NPAC ridge  and NATL pattern influence the snowfall potential.
 

 

 

[SACRUS]

76/65 and mostly cloudy.  Humidity back with some breaks of clouds.  Light showers and clouds much of the day with some late pre sunset clearing.  Wed (9/2) - Fri (9/3) warmer with shot of 90s in the warmer spots, especially Thu and Fri ahead of the front.  L

 

Labor Day weekend looks 5 stars.  Sunny and low 80s and warmer by Monday (Labor Day 7/7) in mid 80s.  Western Ridge / MW/GL trough and Western Atlantic ridge encompassing the east coast expanding west 9/9 - 9/11 for a steam bath it would seem with much cooler air west of us and the likelihood of some big rain amounts into PA.OH, NYS.

 

Beyond there 9/12 - 9/14 cooler before western ridging moves east into the plains and we see warmer weather, EC ridging could sustain itself towards the later part of the back half of the month.  Overall warm looks likely for the long range as a whole.  Guidance will bounce back and forth on the extent of the Western Atlantic ridging but believe for the area it keeps us on the warmer than normal side.

[MJO812]

TS Nana has formed in South America

[Brian5671]

28 minutes ago, MJO812 said:

TS Nana has formed in South America

in south America?  LOL.   You mean north of SA.   Looks like a poss hurricane hit on Guatemala closer to this weekend

[MJO812]

[doncat]

Summer rainfall here of 13.54" was just about normal.

[bluewave]

Extremely amplified pattern coming up. Record 500mb heights forecast along the West Coast by the weekend. Then we see how strong the ridge off the East Coast can get in 7-10 days.
 

 

[donsutherland1]

Tomorrow will be partly to mostly cloudy with possible showers and perhaps a thundershower. Total rainfall amounts will generally be 0.25" or less.

Afterward, temperatures will likely return to above normal levels for several days. However, a deep trough will move from Canada toward the Great Lakes Region and into the Northern Plains starting this weekend. This trough will likely provide a period of somewhat cooler weather. Most of the colder air will stay west of the Appalachians. That trough may persist until near or just after mid-month. Nevertheless, the first half of September will likely wind up somewhat warmer than normal and September, as a whole, will likely finish warmer than normal (generally 1°-3° above normal).

The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall.

The SOI was +18.44.

Today, the preliminary Arctic Oscillation (AO) figure was +0.464.

On August 31, the MJO was in Phase 3 at an amplitude of 1.654 (RMM). The August 30-adjusted amplitude was 1.626.

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°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September.

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.   

Finally, on August 31, Arctic sea ice extent was 3.943 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

 

[SACRUS]

9/1

ACY: 81
LGA: 81
PHL: 81
JFK: 79
TEB: 79
TTN: 79
EWR: 79
New Brnswck: 78
ISP: 78
BLM: 77
NYC: 77

[uncle W]

even in bad la nina winters there can be a two week period when you see most of the snowfall that season...

some la nina winters with a good two week period in an otherwise benign winter....

Jan. 10-24........1965..27.1..50....9..2.11"..14.1"....6.3"....6"
Feb. 10-24.......1972..31.0..58....9..3.48"..12.6"....5.7".....5"
Jan31-Feb 14...1975..29.5..45..16..1.23"..10.6"....7.8".....8"
Jan 8-22...........1984..24.2..46....8..1.15"..10.5"....5.1"...6"
Jan25-Feb 8.....1985..27.3..41..14..1.36"..10.8"....5.7"...7"
Jan28-Feb11....1986..30.4..48..14..1.68"..11.5"....4.5"...6"
Jan20-Feb 3.....2000..24.5..38....8..1.78"..11.7"....5.5"....6"
Jan26-Feb9......2013..31.5..61..11...2.81"..12.2"..11.4"..10"

[LongBeachSurfFreak]

2 hours ago, SI Mailman said:

They classified the naked swirl off the North Carolina coast as Omar which has already been downgraded to a depression.  On the 15th named storm of the year, and more than half of them were barely tropical storms.  

Where are you getting this information???

NHC site has TS Omar. 
 

nice little wave producer in a hurricane swell less season thus far 

[lee59]

3 hours ago, SI Mailman said:

They classified the naked swirl off the North Carolina coast as Omar which has already been downgraded to a depression.  On the 15th named storm of the year, and more than half of them were barely tropical storms.  

Signs of the times

[SI Mailman]

2 hours ago, LongBeachSurfFreak said:

Where are you getting this information???

NHC site has TS Omar. 
 

nice little wave producer in a hurricane swell less season thus far 

you are correct.  I glanced fast at Tropical Tidbits, saw the IR image, and thought I read Tropical Depression Omar based off the advisory.  It's a minimal storm.  

[CIK62]

The next 8 days are averaging 79degs., or 7.5 degs. AN.     Or just 2.5degs. AN, if you do not trust the GFS.

Small tropical system near 36N 69W?

Rainout  next week back after L.D. on the GFS.

72*(93%RH) here at 6am, mean dark clouds, streets wet, drizzle.          Got to 81* by 3pm with a little bit of weak sun.      76* by 6pm.

 

[wdrag]

Good Wednesday morning all: welcomed rains here in far nw NJ since 5A..so far 0.37". 

No topic on the SPC D1-2 marginal risks parts of our area next two days:  You're welcome to add this as a topic. Aside from a wet Wednesday morning in far nw NJ/se NYS /CT,  I see a band or two of heavy showers/tstms sometime after dark both this evening and Thu evening, but EC modeled CAPE continues meager in our area;  so if SVR makes it into our forum area, my expectation is only a couple of reports, mainly western/central NJ.  Still time to add asa topic if model favorability improves. 

On next week: I added a 00z/2 NAEFS prob of 2" or more of the entire period. This is a decent ~30% chance, a week in advance. EPS only has near normal anomaly next week while the GEFS is definitely wetter than normal.  This far in advance,  at least our trough-ridge position is favorable for qpf... but the targeted, repeat episodes is uncertain and should be focused along the quasi-stationary boundary, and upslope regions- which could be a little to our west? 720A/2

[lee59]

52 minutes ago, CIK62 said:

The next 8 days are averaging 79degs., or 7.5 degs. AN.     Or just 2.5degs. AN, if you do not trust the GFS.

Small tropical system near 36N 69W?

Rainout  next week back after L.D. on the GFS.

72*(93%RH) here at 6am, mean dark clouds, streets wet, drizzle.

 

If the GFS is saying 7.5 degrees above normal for the next 8 days, I don't believe it.

[wdrag]

Wantage NJ 0.54" so far 5A-8A.  Definitely valuable rainfall. 

[Jeff Grann]

1 minute ago, wdrag said:

Wantage NJ 0.54" so far 5A-8A.  Definitely valuable rainfall. 

We are getting a good steady drenching here at West Point. 

[lee59]

13 minutes ago, Jeff Grann said:

We are getting a good steady drenching here at West Point. 

We had it yesterday morning with .44 of an inch. This morning light rain and drizzle.

[Brian5671]

Nice steady rain here on the southern edge of the rain shield...

[donsutherland1]

Morning thoughts...

At 8:20, a large area of light rain with some embedded heavier showers was moving eastward across southern and central New York State and Connecticut. The rain was north of New York City. Another area of showers was located in eastern Pennsylvania. Today will be mostly cloudy with some showers. Thundershowers are possible this evening and tonight as a warm front moves northward. Temperatures will will reach the upper 70s and lower 80s across the region. Likely high temperatures around the region include:

New York City (Central Park): 80°
Newark: 83°
Philadelphia: 85°

Tomorrow and Friday will be noticeably warmer days. Afterward, a deep trough in Canada will move toward the Great Lakes Region and provide a period of somewhat cooler weather. That trough may persist until near mid-September.

 

[wdrag]

Wantage NJ... 0.69" so far since 5A.. beneficial!

[SACRUS]

73/71 and cloudy.  Dew points are back.  Continued clouds / storms and shower chances today with highs from the mid 70s to low 80s depending if we can get into any clearing. More widespread storms overnight and into tomorrow morning. Thu warmer but still storms and clouds around so temps may be capped in the mid 80s.  Should we see more sun the chance at 90 exists in the hot spots like LGA, EWR metro areas CNJ etc.  More widespread storms Thu evening.  Friday we are clearing out and drying out for a gorgeous Labor Day Weekend.  Highs in the low 80s Sat (9/5) and Sun (9/6). By Labor day we are warming back up to mid 80s.  Western ridge builds heat dome into the southwest again for some record highs labor day weekend out there..

9/8 - 9/14.  West ern Coast Ridge  with Western Atlantic Ridge expanding west  bringing warm south / onshore flow to the EC with deep trough into the MW/ GL.  Brunt of the cool and rain stays west but wouldnt surprise to see some cloudy days but overall warmer.  Pattern still a bit tricky as to the extent of the ridging and its center position.  Beyond there and for the second half of the month looks warmer in the EC with trough pushing into the west and WC ridge building east into the plains.  WAR also likely to influence the area.

 

[NJwx85]

[CIK62]

The T's for the GFS OP which I am getting from the WB site, are too high at least around this part of the earth and during the summer----maybe all  the time.        Even worse would be an unpredictable magnitude and directional error that varied by location and time of the year! lol.

In the last two years it has indicated more 100-Degree Days would occur than 100-Degree Days in the City's history (about 60 in 151 years).    There were none, other than a lone 100 at LGA last year.      Last year it had the nerve to show 5 straight 100-Degree Days with two of them breaking the All-Time High of 106-----a 107 then 108 the next day!!!    It has shown 16-day stretches that would average +12 or better if correct----etc.

Now that members have asked,  I am simply removing 5 degrees on these 8-day estimates, which include the current day.     So I assume when it shows Normal for the next 8 days-----this could turn out to mean -5!

[bluewave]

Less warm is the new cool.

 

 

[NJwx85]

12 minutes ago, bluewave said:

Less warm is the new cool.

 

 

Hopefully we torch until just before Thanksgiving.

[Jeff Grann]

1 hour ago, lee59 said:

We had it yesterday morning with .44 of an inch. This morning light rain and drizzle.

We will be pushing an inch soon here. 

[bluewave]

31 minutes ago, NJwx85 said:

Hopefully we torch until just before Thanksgiving.

Looks like any major heat will be limited by clouds and onshore flow. But the warmer than normal minimums may take the lead with the higher dew points and winds off the still warm ocean.

 

[wdrag]

0.97 so far...  since 5A.  Not well modeled.  Surprised HRDPS missed this on its very short term forecast.