September 2020 wx discussion

[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

[bluewave]

1 hour ago, gravitylover said:

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

 

 

 

[Rtd208]

[Brian5671]

4 minutes ago, Rtd208 said:

models starting to agree on  big rain event this week-much needed.

[bluewave]

3 hours ago, Brian5671 said:

models starting to agree on  big rain event this week-much needed.

Hartford is hoping for their first 1”+ rain event since late April.

 

[donsutherland1]

Under partly to mostly cloudy skies, temperatures rose mainly into the middle 70s across the region.

In parts of South America, a historic early spring heatwave toppled monthly records. Some monthly records included:

Asuncion, Paraguay: 108°
Corrientes, Argentina: 109°
Foz Do Iguacu, Brazil: 102°
Pozo Hondo, Paraguay: 114° ***New all-time national high temperature record***

Meanwhile, in parts of Europe, early-season snows blanketed even the lower elevations of the Alps.

Temperatures will likely remain at generally above normal levels for the remainder of September. A cool shot is likely during the opening week of October, but warmer readings could return during the following week.

Phoenix has an implied 95% 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 95.4°. 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.

October could be wetter than September in and around the New York City area. Since 1950, 10 of the 12 (83%) of the La Niña cases that followed an El Niño winter saw October receive more precipitation than September, including 7 of the 8 (88%) cases since 1980. October 1954 and October 1998 were the exceptions. The largest increase in precipitation occurred in 2005. September 2005 saw just 0.48" precipitation in New York City. October 2005 received 16.73" precipitation.  

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 +16.11.

Today, the preliminary Arctic Oscillation (AO) figure was +0.683.

On September 25, the MJO was in Phase 5 at an amplitude of 1.350 (RMM). The September 24-adjusted amplitude was 1.442.

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 85% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.6°.

 

[SACRUS]

9/26

PHL: 78
ACY: 77
LGA: 77
ISP: 76
JFK: 76
TEB: 76
TTN: 75
EWR: 75
New Brnswck: 75
NYC: 74
BLM: 73

[Santa Claus]

sup boys.  took a drive up to Franklin Lakes, just day 12 in a row of super gorgeous weather.

little jumping spider guy

and the cup de'grass, i found several fishing spiders on the shore of Franklin Lakes... Franklin Lake... not actually sure what the name of this specific lake is... anyway this spider is probably the largest spider species endemic to New Jersey.  these are the dark fishing spider Dolomedes tenebrosus, or your money back.

also, several of these spiders had hatched baby spiders in their nests.  the spiders hatch and then huddle into a ball.  a ball of baby spiders.  i found out so many terrible things today.

but yeah great weather today.

[CIK62]

The last 4 days of September are averaging 73degs.         Making it 69degs., or +4.

Month to date is  -0.2[68.5].      September should end at 68.6, within +1.0.

69*(93%RH) here at 6am.        75*(80%RH) by 1pm.-clouds back in after hours of some sun.     More sun again and up to  78* by 4pm.

[bluewave]

Very unusual rainfall distribution this month. Portions of Long Island experienced one of their wettest starts to September. This was followed by record dry conditions since then. Heavy rains to end the month will only add to the oddity.

9-10....Pt Lookout....6.47.....Massapequa....5.41...Wantagh Mesonet...4.64....Amityville....4.04....Copaigue....4.05

 

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

Rank	Ending Date	Total Precipitation Sep 11 to Sep 26	Missing Count
1	1910-09-26	0.00	0
-	1908-09-26	0.00	0
-	1884-09-26	0.00	0
2	2020-09-26	T	0
-	1941-09-26	T	0
-	1917-09-26	T	0

 

[donsutherland1]

Morning thoughts...

Today will be mainly cloudy with perhaps a few widely scattered showers. Temperatures will likely reach the middle to perhaps upper 70s across the region. Likely high temperatures around the region include:

New York City (Central Park): 76°
Newark: 78°
Philadelphia: 79°

The temperature will likely remain above normal through the remainder of the month. Cooler air will arrive to start October.

 

[Brian5671]

1 hour ago, bluewave said:

Very unusual rainfall distribution this month. Portions of Long Island experienced one of their wettest starts to September. This was followed by record dry conditions since then. Heavy rains to end the month will only add to the oddity.

9-10....Pt Lookout....6.47.....Massapequa....5.41...Wantagh Mesonet...4.64....Amityville....4.04....Copaigue....4.05

 

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

Rank	Ending Date	Total Precipitation Sep 11 to Sep 26	Missing Count
1	1910-09-26	0.00	0
-	1908-09-26	0.00	0
-	1884-09-26	0.00	0
2	2020-09-26	T	0
-	1941-09-26	T	0
-	1917-09-26	T	0

 

basically 2 big rainfall events and absolutely nothing in between, not even a .10 shower....very odd

[bluewave]

4 minutes ago, Brian5671 said:

basically 2 big rainfall events and absolutely nothing in between, not even a .10 shower....very odd

Another  example of these abrupt precipitation shifts that many areas are experiencing. Very challenging time to be in the agricultural industry. We can swing from one extreme to another. 

 

[SACRUS]

72/66 and some breaks in the mainly low clouds.  Low of 62 last night.  Pending on sunshine today will be warm with highs near or low 80s.  More of the same on Monday and Tuesday and perhaps the warmest days till next March / April. Front moves in and brings the first measurable rain since 9/11 Tue (9/29) - Thu (9/30) .  Front linger near the areas Tuesday - Thursday.  Wednesday and Thursday look the wettest with wave of low pressure running up the front with >1 inch and possible widespread 1 - 3 inch amounts.

Fri 10/1 - Tue 10/6 : Cooler as trough digs into the Plains, MW and swings through.  Brunt of the strongest cold stays west and overall not as cool as the past period (9/19 - 9/22)  but there will be some chilly air swinging through 10/4 - 10/6 before we moderate and warmup 10/7.  Beyond there need to see if the West Coast ridge rebuilds or flatter flow keeps us near/warmer than normal.  EC ridging is possible with some stronger warmth (against normal) the back half of the month.

9/27 - 9/30 : Warmer to much warmer than normal (+5 to +7).   

9/30 - 10/1 : Rain, first in 3 weeks or since 9/11.  1 - 3 inches 

10/2 - 10/7: Cooler / chilly (-3 to -5) overall coolest 10/4- 10/6 / frost inland

10/7 : warmup (temp or more sustained near/above normal ?)