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Rtd208

October 2018 Discussions & Observations Thread

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1 hour ago, winterwx21 said:

Looking like a great first week of October for people that want late season warmth. High temps upper 70s to near 80 all week long.

Hasn't it been that way for years now. Quite obvious this is our new normal. 

I can't recall the last time we started out cold in early October.

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3 hours ago, winterwx21 said:

Looking like a great first week of October for people that want late season warmth. High temps upper 70s to near 80 all week long.

Sunny and dry, not too hot. Perfect for foliage

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An abnormally warm September is now concluding. An abnormally warm October appears poised to start.

Early hints in the extended guidance for a chilly start to October have yielded to the realities of persistent Western Atlantic and eastern ridging. Rather than starting cool, October will commence on a warm note. There is even the potential that the first 10 days of October could be among the 10 warmest starts for that timeframe. A mean temperature of 67° or above appears likely.

Since 1869, there have been 12 cases during which the October 1-10 period had a mean temperature of 67° or above. Two-thirds of those years went on to see October average 60° or warmer, even as 60° Octobers have occurred in just 23 years. The 12 years with an October 1-10 mean temperature of 67° or above were as follows:

1879: October mean temperature: 60.4° 
1898: October mean temperature: 59.5°
1922: October mean temperature: 58.1° (coolest October among those cases)
1927: October mean temperature: 59.5°
1931: October mean temperature: 61.2°
1941: October mean temperature: 60.7°
1949: October mean temperature: 63.1°
1959: October mean temperature: 59.8°
1990: October mean temperature: 61.9°
2007: October mean temperature: 63.6°
2013: October mean temperature: 60.2°
2017: October mean temperature: 64.1° (warmest October on record)

Mean October average temperature: 61.0°
Median October average temperature: 60.6°

Four of the above cases with October mean temperatures of 60° or above were preceded by a September with a mean temperature of 70° or above, as will all but certainly be the case this year: 1931, 1941, 2007, and 2017.

Taking the guidance (MOS and EPS) through October 10 and assuming seasonal readings for the remainder of the month (even as the forecast teleconnections hint at somewhat above normal readings through at least mid-month), sensitivity analysis offers the following implied probabilities:

Warmer than normal: 67%
Mean temperature of 60° or above: 49%
Record warm October: 25%

The last time October had a below normal average temperature in New York City was 2009.

Finally, given the current guidance, it is plausible that Central Park will have no minimum temperatures below 50° through October 10. Only 10 prior years had yet to see a reading below 50° through October 10, four of which occurred 2000 or later.

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19 minutes ago, donsutherland1 said:

An abnormally warm September is now concluding. An abnormally warm October appears poised to start.

Early hints in the extended guidance for a chilly start to October have yielded to the realities of persistent Western Atlantic and eastern ridging. Rather than starting cool, October will commence on a warm note. There is even the potential that the first 10 days of October could be among the 10 warmest starts for that timeframe. A mean temperature of 67° or above appears likely.

Since 1869, there have been 12 cases during which the October 1-10 period had a mean temperature of 67° or above. Two-thirds of those years went on to see October average 60° or warmer, even as 60° Octobers have occurred in just 23 years. The 12 years with an October 1-10 mean temperature of 67° or above were as follows:

1879: October mean temperature: 60.4° 
1898: October mean temperature: 59.5°
1922: October mean temperature: 58.1° (coolest October among those cases)
1927: October mean temperature: 59.5°
1931: October mean temperature: 61.2°
1941: October mean temperature: 60.7°
1949: October mean temperature: 63.1°
1959: October mean temperature: 59.8°
1990: October mean temperature: 61.9°
2007: October mean temperature: 63.6°
2013: October mean temperature: 60.2°
2017: October mean temperature: 64.1° (warmest October on record)

Mean October average temperature: 61.0°
Median October average temperature: 60.6°

Four of the above cases with October mean temperatures of 60° or above were preceded by a September with a mean temperature of 70° or above, as will all but certainly be the case this year: 1931, 1941, 2007, and 2017.

Taking the guidance (MOS and EPS) through October 10 and assuming seasonal readings for the remainder of the month (even as the forecast teleconnections hint at somewhat above normal readings through at least mid-month), sensitivity analysis offers the following implied probabilities:

Warmer than normal: 67%
Mean temperature of 60° or above: 49%
Record warm October: 25%

The last time October had a below normal average temperature in New York City was 2009.

Finally, given the current guidance, it is plausible that Central Park will have no minimum temperatures below 50° through October 10. Only 10 prior years had yet to see a reading below 50° through October 10, four of which occurred 2000 or later.

Great info as always.  Any correlation to the ensuing winter ? 

 

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Looks like a continuation of the well above normal temperatures into October. Notice how the continuing record WAR pattern is pretty much the opposite of what you would expect to see during an El Nino October. It appears that the atmosphere is still stuck in more of a warmer La Nina October 500 mb pattern like the last few years. Maybe the El Nino is still to weak to impact the pattern.

EPS forecast

ecmwf-ens_z500aMean_namer_4.thumb.png.14b486f88f3f01812cd446c9a6ccb7ae.png

 2 recent La Nina Octobers

IMG_0255.PNG.253c717cc45c8173ba32bd553a28d422.PNG

Last 6 El Nino Octobers

IMG_0254.PNG.9c3c34d6bb47da2da1c0f1611e0b9c9e.PNG

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2 hours ago, bluewave said:

Looks like a continuation of the well above normal temperatures into October. Notice how the continuing record WAR pattern is pretty much the opposite of what you would expect to see during an El Nino October. It appears that the atmosphere is still stuck in more of a warmer La Nina October 500 mb pattern like the last few years. Maybe the El Nino is still to weak to impact the pattern.

EPS forecast

ecmwf-ens_z500aMean_namer_4.thumb.png.14b486f88f3f01812cd446c9a6ccb7ae.png

 2 recent La Nina Octobers

IMG_0255.PNG.253c717cc45c8173ba32bd553a28d422.PNG

Last 6 El Nino Octobers

IMG_0254.PNG.9c3c34d6bb47da2da1c0f1611e0b9c9e.PNG

Maybe this raises the odds of a warmer October overall extending well into November and then a sudden flip.  Or, even the possibility of warmer weather continuing even deeper into the Fall. 

Like you had mentioned before in other posts, the recents Fall seasons have been rather warm. And winter a few times has extending in late March. 

 

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2 hours ago, bluewave said:

Looks like a continuation of the well above normal temperatures into October. Notice how the continuing record WAR pattern is pretty much the opposite of what you would expect to see during an El Nino October. It appears that the atmosphere is still stuck in more of a warmer La Nina October 500 mb pattern like the last few years. Maybe the El Nino is still to weak to impact the pattern.

EPS forecast

ecmwf-ens_z500aMean_namer_4.thumb.png.14b486f88f3f01812cd446c9a6ccb7ae.png

 2 recent La Nina Octobers

IMG_0255.PNG.253c717cc45c8173ba32bd553a28d422.PNG

Last 6 El Nino Octobers

IMG_0254.PNG.9c3c34d6bb47da2da1c0f1611e0b9c9e.PNG

I have been on board for a warmer fall but nothing extreme though. I think the bottom falls out in mid to late November right around Thanksgiving.

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1 hour ago, frd said:

Maybe this raises the odds of a warmer October overall extending well into November and then a sudden flip.  Or, even the possibility of warmer weather continuing even deeper into the Fall. 

Like you had mentioned before in other posts, the recents Fall seasons have been rather warm. And winter a few times has extending in late March. 

 

It's interesting the differences  between recent October's and March's...Haven't seen a really below normal Oct since 2009...March is the opposite, since 2013, only 2016 was above normal...the other five years were solidly below.

 

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RWTT continues showing no BN period till second week of Nov., which looks stormy as air masses clash.  

AN wins apparently, since the next 90 look as AN as the next 30, say +3 to +5.   The Halloween period has, and continues to show way AN.

With an AN September about to be written up, the score for the past 60 months is:                    AN---39  BN---21...... including 20 straight AN months three years as the QBO skipped a beat or two.  lol

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12 hours ago, bluewave said:

Looks like a continuation of the well above normal temperatures into October. Notice how the continuing record WAR pattern is pretty much the opposite of what you would expect to see during an El Nino October. It appears that the atmosphere is still stuck in more of a warmer La Nina October 500 mb pattern like the last few years. Maybe the El Nino is still to weak to impact the pattern.

EPS forecast

ecmwf-ens_z500aMean_namer_4.thumb.png.14b486f88f3f01812cd446c9a6ccb7ae.png

 2 recent La Nina Octobers

IMG_0255.PNG.253c717cc45c8173ba32bd553a28d422.PNG

Last 6 El Nino Octobers

IMG_0254.PNG.9c3c34d6bb47da2da1c0f1611e0b9c9e.PNG

What happened to all the calls of mean trough in East, remember the eps was "locked" in two weeks ago and every met was talking about it.

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8 hours ago, forkyfork said:

it never ends

ecmwf-ens_T850a_us_fh48-240.gif

It may be enough to give us a 90F reading and models could easily trend stronger with the ridging. Incredible.

We should see multiple days in the 80s. 

On the other hand if the ridging keeps building north then we'll probably see more onshore flow with the mins generating the greatest departure from normal. 

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11 hours ago, qg_omega said:

What happened to all the calls of mean trough in East, remember the eps was "locked" in two weeks ago and every met was talking about it.

This has been the model error for months. The ensembles have been too weak with the WAR/SE Ridge during their week 2 forecasts. The closer in time we get, the stronger the models correct with the WAR. To compound error in this case, the MJO is increasing in amplitude now.

0z 9-23 EPS run for 0z 10-3

ecmwf-ens_z500a_namer_11.thumb.png.62535ecc56db86ec191c1ab0a4a20b8d.png

0z 9-30 run for 0z 10-3

ecmwf-ens_z500a_namer_4.thumb.png.296ba4cf3d44e74105c383dca77bee60.png

 

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At least having way above normal temps in October is much better than having above normal temps during the summer. High temps in the low 80s with moderate humidity (dewpoints in the 60s) is pretty comfortable and nice weather for outdoor activities. Not like during the summer when it was miserable with dewpoints in the 70s to go along with 90 degree temps. I'm fine with a warm pattern for October-November as long as it flips in time for winter.

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Following a record fourth consecutive September with a mean temperature of 70° or above, October is poised to begin on a balmy note. Based on the guidance, there is a possibility that the first week of October could have an average temperature of 70° or above in New York City.

Since 1869, only 8 prior years have seen the first week of October average 70° or above:

1898: 70.9°
1922: 70.8°
1927: 71.6°
1931: 70.2°
1941: 73.3°
1959: 71.3°
2007: 71.8°
2013: 70.9°

50% of those months went on to average 60.0° or above.

the implied probabilities using sensitivity analysis applied to the MEX MOS and EPS are:

Above normal: 75%
60.0° or above mean temperature: 57%
Record warm October: 43%

Looking farther ahead to the winter, the snowfall outcomes for those cases were mixed. There were three very snowy winters for NYC: 1898-99: 55.9", 1959-60: 39.2", and 2013-14: 57.4". There were four winters with less than 20" snowfall for NYC: 1927-28: 14.5", 1931-32: 5.3", 1941-42: 11.3", and 2007-08: 11.9".

Finally, Tampa, which is fresh off after having registered its warmest month ever with an 85.9° mean temperature in September (old monthly record: 85.5°, June 1998), could have among the warmest first weeks in October on record. The current record was set just last year with a mean temperature of 82.6°.

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The first 8 days of Oct. are averaging 71degs., or about 11degs. AN.   11 days of double digit 850mb T's incoming when the normal is 9C on the first already!?

Yes, Tampa set records Sat./Sun. of 97 each, or +10, in concluding its warmest month ever.

The RWTT shows no BN period here till second week of Nov.   In fact, another back to back record Oct. to go with the Feb. fiasco of breaking the previous February's all time record, is possible.   Remember Feb. 21 record heat and 500mb. height blowout.

For us, +5/6 and for Tampa +1/2.  Pacific NW is BN., for Oct.

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Above average temperatures are on tap for the next two weeks as persistent troughs sets up over the West Coast.

Btw, need a new subscription service for the winter. Weatherbell or Stormvista?

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there were mild Octobers before some great winters with a variety of enos's...there have been great winters after a cold October and vise versa...

1947...

1963...

1995...

last year...

 

 

warm oct.png

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2 hours ago, uncle W said:

there were mild Octobers before some great winters with a variety of enos's...there have been great winters after a cold October and vise versa...

1947...

1963...

1995...

last year...

 

 

warm oct.png

This warm spell could bring some warm SST's in the Great Lakes area that could make for an active time for those folks in the snow belt areas in months to come.

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2 hours ago, uncle W said:

there were mild Octobers before some great winters with a variety of enos's...there have been great winters after a cold October and vise versa...

1947...

1963...

1995...

last year...

 

 

 

I have a hard time with last year being a great winter. Yes March was pretty inspiring and that early January cold shot was significant but as a whole I have a hard time giving the winter a higher grade than a B+. That warm 6 weeks and the warmth in between the snows in March just killed it for me.

Today turned out to be an ok day, a bit too muggy for my tastes this morning and not enough sun but temps are reasonable.

 

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