October 2020 General Discussions & Observations Thread

[Cfa]

71/51 split today. 0.01” this AM from a very short lived downpour.

[CIK62]

The next 8 days are averaging 67degs.      Making it 62degs., or about +3.0.

60*(85%RH) here at 6am.          68* by Noon.      70* at 1pm.        72* at 2pm.        74* at 2:30pm, wild SW winds picking up sand now(I am at home of course)

Tropics:   20.6N  86.3W.

GFS still wet here next Monday from the above system 'Delta'.        EURO has little rain here.      EURO hits the TX/LA border, and the GFS is east of this.     Remnants do not get get to be over the Atlantic on the EURO, so nothing here.

[wdrag]

Good Wednesday morning everyone,  No DELTA post yet... Modeling differs quite a bit still with the EC and it's EPS unwilling to join NAEFS/GEFS. I think it will begin showering here late Saturday or definitely Sunday (FGEN with a cold front and DELTA moisture leak northeastward well ahead) with a cool rainy Monday, BUT modeling is not agreement and therefore I'm not quite willing to express enough confidence for a DELTA remnant post tropical TOPIC 2"+ rainfall, Gust 35 Knot event here late Sunday-Monday.

In the meantime, I'll start a post for the wind advisory 1P-10P.  Am not quite as gong ho as I'd like to be. LI-CT/SE NYS have best chance for scattered 46+ MPH gusts.  I think the max G might make 60 MPH vicinity e LI but not likely. More in the topic. Thanks for the previous prompts on this topic. 

[donsutherland1]

Morning thoughts...

Today will be partly to mostly sunny and increasingly windy ahead of an approaching cold front. Winds will likely gust past 45 mph this afternoon and evening. In addition, there could be some widely scattered showers or even thundershowers this afternoon and early tonight. Temperatures will rise into the middle 70s and perhaps upper 70s in some areas. Likely high temperatures around the region include:

New York City (Central Park): 75°
Newark: 78°
Philadelphia: 77°

Milder conditions will quickly return toward the weekend.

 

[bluewave]

Longer range, models have been struggling with the Pacific Jet. This has resulted in fast wavelength changes over PNA and EPO regions. So a continuation of the up and down temperature pattern for us. Also notice how the PDO is really getting pushed around by these quick changes. 
 

New run

Old run

[wdrag]

Posting the 06z/7 analysis by OPC.  Note DELTA near the Yucatan.  Now the 00z/27 (10 day outlook) of the GEFS members and a few down near the lower left (Yucatan).  Many members with tropical too close to FL.  Still this is not a bad outlook for potential. I did not include the EFS members-wasn't thinking about the EPS at that time.

[SACRUS]

70 sunny and breezy.  2 day cool down Thu (10/8) and Fri (10/9) much muted vs previous guidance followed by a 7 - 10 day warm period with temperatures running around +5 for the period as a whole.  We'll have to see how much rain works in Sunday night into Monday from Delta and then any subsequent warm fronts.  Cool down towards 10/20 liekly  but may be temporary before height come up along the east coast.

[Stormlover74]

6 minutes ago, SACRUS said:

70 sunny and breezy.  2 day cool down Thu (10/8) and Fri (10/9) much muted vs previous guidance followed by a 7 - 10 day warm period with temperatures running around +5 for the period as a whole.  We'll have to see how much rain works in Sunday night into Monday from Delta and then any subsequent warm fronts.  Cool down towards 10/20 liekly  but may be temporary before height come up along the east coast.

Gfs has consistently been showing the rain for Monday but euro's not biting

[bluewave]

16 minutes ago, Stormlover74 said:

Gfs has consistently been showing the rain for Monday but euro's not biting

We'll see if the Euro is going too far west with Delta like it did with Laura. It would be nice to see what the new 9km ensembles show. 

[donsutherland1]

16 minutes ago, Stormlover74 said:

Gfs has consistently been showing the rain for Monday but euro's not biting

It does show up on some of the EPS ensemble members, though few show a significant amount.

[Rtd208]

Current temp is up to 76 here.

[uncle W]

79 imby after hitting 80...

[binbisso]

70° here after hitting a high of 71 and windy

[CIK62]

Models are helpless and hopeless in determining if we will get any rain here Sun/Mon.       The NWS on KWO-35 does not even have the word rain in its forecast for the period.       EURO has T going past 80 then.        Look out GFS!  I am the champ when it comes to future high T's around here----the EURO exclaims!!

EURO still just a TRACE over the next 10 days.          GFS has 2"+.

EURO Weeklies Control Member has no RAIN till Halloween, I believe!

[bluewave]

On 10/7/2020 at 2:49 PM, CIK62 said:

Models are helpless and hopeless in determining if we will get any rain here Sun/Mon.       The NWS on KWO-35 does not even have the word rain in its forecast for the period.       EURO has T going past 80 then.        Look out GFS!  I am the champ when it comes to future high T's around here----the EURO exclaims!!

EURO still just a TRACE over the next 10 days.          GFS has 2"+.

EURO Weeklies Control Member has no RAIN till Halloween, I believe!

The 12z Euro has a good soaking now that it came east with Delta.

 

[CIK62]

Yep.    This is a big flip.     Crosses coast further east in the Gulf.     Goes to show that atmospheric models can change faster than a political candidate.     Watch the debate tonight.

[wdrag]

Thats correct: The EC and EPS GEFS ensembles are now much more similar to each other and the NAEFS continues with rain later Sunday afternoon into Monday, possibly even Tuesday and Wednesday with additional showery bouts.  Will reevaluate for a topic tomorrow morning.  No doubt the EC joined NAEFS and GEFS with its 12z/7 cycle. 

[wdrag]

Wantage NJ .01 earlier this afternoon. MAX G 32 MPH at 520P. 

[psv88]

75 today

[LibertyBell]

3 hours ago, bluewave said:

The 12z Euro has a good soaking now that it came east with Delta.

 

wow 5 inches in the Poconos and 3 inches here, is the other guidance similar?

any wind issues?

 

[Stormlover74]

21 minutes ago, LibertyBell said:

wow 5 inches in the Poconos and 3 inches here, is the other guidance similar?

any wind issues?

 

Gfs is centered on our area

 

[MJO812]

Its eventually coming

[LibertyBell]

2 minutes ago, Stormlover74 said:

Gfs is centered on our area

 

looks west to east, centered on central-eastern PA to N NJ, NYC and LI....I wish we get storms like this in the winter too (with snow of course)

 

[donsutherland1]

In the wake of a frontal passage, clouds will give way to clearing skies. It will remain breezy overnight. Tomorrow will be sunny and noticeably cooler with highs mainly in the lower and middle 60s across the region.

Afterward, a pronounced and sustained warmup is possible. By mid-month, New York City will likely have an October 1-15 mean temperature above 60° and the region will likely see temperatures running an overall 1°-3° above normal.

The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around September 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.82°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely prevail into at least the start of winter.

The SOI was +13.99.

Today, the preliminary Arctic Oscillation (AO) figure was +0.479.

On October 6 the MJO was in Phase 5 at an amplitude of 1.200 (RMM). The October 5-adjusted amplitude was 1.196.

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. Among that pool, October 1983 and 2016 featured above normal and near normal rainfall respectively. October 1988 and 1998 saw below normal and much below normal rainfall respectively.

Based on sensitivity analysis applied to the latest guidance, there is an implied 65% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.5°.   

 

[SACRUS]

10/7

EWR: 79
ACY: 79
PHL: 79
BLM: 78
JFK: 78
New Brnswck: 78
LGA: 77
TTN: 77
ISP: 75
NYC: 74
TEB: 74

[uncle W]

1 hour ago, donsutherland1 said:

In the wake of a frontal passage, clouds will give way to clearing skies. It will remain breezy overnight. Tomorrow will be sunny and noticeably cooler with highs mainly in the lower and middle 60s across the region.

Afterward, a pronounced and sustained warmup is possible. By mid-month, New York City will likely have an October 1-15 mean temperature above 60° and the region will likely see temperatures running an overall 1°-3° above normal.

The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around September 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.82°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely prevail into at least the start of winter.

The SOI was +13.99.

Today, the preliminary Arctic Oscillation (AO) figure was +0.479.

On October 6 the MJO was in Phase 5 at an amplitude of 1.200 (RMM). The October 5-adjusted amplitude was 1.196.

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. Among that pool, October 1983 and 2016 featured above normal and near normal rainfall respectively. October 1988 and 1998 saw below normal and much below normal rainfall respectively.

Based on sensitivity analysis applied to the latest guidance, there is an implied 65% probability that New York City will have a warmer than normal October. October will likely finish with a mean temperature near 58.5°.   

 

58.5 would be average for the 1931-60 period...its about a degree above average for the last 30 year period...

[CIK62]

The next 8 days are averaging 67degs.       Making it 62degs., or about +4.0.

57*(RH56%) here at 6am.    56* at 6:30am, m. clear.       60* by Noon.    62* at 1pm.       64* by 4pm.

Tropics:   28.4N  91.7W

Well, KWO-35 finally put the word rain into their forecast starting Sunday---- proofing that even an AMBE Chip Voice can be right.     Seriously, they must have been following the rainless EURO.

[wdrag]

Looking ahead: No topic yet... beneficial rain on the way and over the period of Sunday afternoon (11)-Wednesday night (14th), a pretty high probability that much of our NYC forum receives 2 inches, with spotty 4+ possible. I've added the 00z/8 cycle WPC outlook and the NAEFS probability of 2+".  It probably occurs in several pieces with main DELTA remnant later Sunday-Monday night. Thereafter, a couple more bands Tuesday and Wednesday. PWAT will be generally 1.5" through this period, provided the DELTA remnant trough doesn't drive the PWAT axis offshore for Tuesday-Wednesday. 630A/8

[bluewave]

It will be interesting to see if Delta slows down enough for both Monday and Tuesday to record at least an inch of rain in NYC. Most of our events in recent years had the heaviest precipitation focused into just 1 day. The last 2 consecutive NYC days with 1.00” plus of precipitation was 1-23/24-17. Getting 2 consecutive days of 2.00”+ has been even tougher. The last time for NYC was with Irene on 8-27/28-11.

Number of Consecutive Days Precipitation >= 1.00 
for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
Last value also occurred in one or more previous years.
Period of record: 2017-01-01 to 2020-10-07
1	2	2017-01-24
2	1	2020-09-30
-	1	2020-09-10
-	1	2020-08-12
-	1	2020-07-22
-	1	2020-07-10
-	1	2020-04-13
-	1	2020-03-23
-	1	2019-12-14
-	1	2019-12-09

 

Number of Consecutive Days Precipitation >= 2.00 
for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Run Length	Ending Date
Last value also occurred in one or more previous years.
Period of record: 2011-01-01 to 2020-10-07
1	2	2011-08-28
2	1	2020-07-10
-	1	2018-08-11
-	1	2018-07-17
-	1	2018-04-16
-	1	2017-10-29
-	1	2017-05-05
-	1	2016-11-29
-	1	2016-01-23
-	1	2015-01-18

[wdrag]

Appears to me from RAL tracks, that the primary DELTA goes west of us Monday but a triple point low, in part caused by the strong cool high to our northeast Sunday may focus 1-2" qpf in a part of our forum on Monday.  

My expectation is the later Sunday portion will be associated with FGEN banding well in advance of DELTA... working on showery Louisiana 700 MB moisture that arrives here this weekend.  The Monday rains should be more DELTA involved.  Trailer cool frontal band Tuesday...then does it stall over our area Wednesday as a new northern stream trough digs down into the Great Lakes or does it progress eastward out to sea.  

My guess for NYC CP CLI is 0.3" Sunday, anywhere from 0.5 to 2.5" Monday depending on triple point formation or not,  and then Tues could be less than 0.5" with Wednesday unknown but I don 't see Wednesday as necessarily a null day... that day to me is the larger uncertainty. That gives me a NYC CP range by Wed night of 1" minimum to 3.2" max as a very early attempt at ranging... the normal D4-7 uncertainty caveat.