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RECORD WARMTH TO RECEDE AS WESTERN STORMINESS EASES

By: Steve Gregory , 7:54 PM GMT on February 21, 2017

TUESDAY: 21-FEB-17 / 1:55 PM CST

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DUE TO TRAVEL REQUIREMENTS UPDATES WILL BE SHORTER & LESS FREQUENT UNTIL FURTHER NOTICE


ALSO: THERE WILL BE NO NEW BLOGS UNTILTHE NEW BLOG SYSTEM GOES ONLINE APRIL 3. (I will post under the Category6 - though unsure of my 'schedule' for posts.

UNUSUAL WARMTH TO RECEED TOWARDS ‘NORMAL’ AS SUBTLE
BUT IMPACTFUL PATTERN EVOLUTION BEGINS THIS WEEK

The extraordinary warmth over the central-eastern US will gradually dissipate as the large scale ridge that has dominated the weather across the central and eastern US for over a week breaks down – allowing the overall weather pattern to trend towards more ‘seasonal’ but quite active levels.

The deep TROF near the west coast be ejecting several strong short wave TROFs eastward this week – helping to break down the amazingly strong ridge that has brought all-time record warmth to the central and eastern US to give way to more seasonal Temps – especially during Week 2. (Chicago has had the warmest FEB 16-21 Temps on record – including at least 3 days with highs of 70˚. Until this past week, there have only been 4 occurrences in all of FEB with 70˚ readings in the last 145 years.)

The main driver for the subtle but significant pattern shift is the strong MJO that has now weakened and is moving across Africa towards the Indian Ocean. This, along is bringing a shift to the tropical forcing pattern that helped to originally setup the ridge over the center of the nation – and will allow heights (and Temps) to fall off across Canada and then the central US starting this week.

There remains some significant uncertainty beyond 10-days on just how big a pattern change will be forthcoming – with some model forecasts calling for a strong mean TROF to form over the eastern US during the first week in MAR – while the most recent model runs have trended towards a mean TROF across the western interior with strong short waves ejecting towards the northeastern US. For the time being, the highest probability outcome is for near to at times below normal Temps across the eastern half of the nation during early MAR – but with large Temp swings every few days between storm/frontal system passages. At the same time, Temps will remain somewhat below normal over the western interior, with near to above normal Temps developing across the SW US. Further out in time, there are SOME indications that Temps will again move to above normal levels in late MAR on into APR.




Fig 1: Temperature ANOMALY forecast for Week 1 is based STRICTLY on the MOS data forecasts from today’s 12Z operational GFS model run (with only minor adjustments towards the raw model data points for Days 6-8).Unusally warm Temp anomalies will ease off from west to east this week though will remain far above normal levels on average east of the Rockies. Well below normal readings will persist in the west. Overall confidence is very high with excellent temporal and regional model agreement – with a reading of ‘5’ for the pattern and ‘4’ for actual anomaly magnitudes on a scale of 1 to 5.


Fig 2. The Week 2 Temperature ANOMALY forecast is based on the 12Z run of the GFS (80%) integrated with the 12Z GFS Ensemble (5%), ECMWF Ensemble (5%) and Climatology (10%) using the projected pattern along with explicit surface and 850mb (~5,000 FT) Temp forecasts. Some Temps are adjusted for known or expected anomalous thermal patterns & projected storm system passages.ON AVERAGE, warmer than normal Temp anomalies should persist over the eastern half of the nation on average - thpough Temps will fall below normal in the Midwest and eventually the NE US by late in the week. Overall confidence is near average for the anomaly pattern with a bit below normal confidence in anomaly magnitudes for this time of year due to rapidly moving weather systems and associated swings in Temps; with a reading of ‘3’ for the pattern and a ‘2’ for actual anomaly magnitudes on a scale of 1 to 5.

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Steve



The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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28. SlabTown
11:49 AM GMT on March 27, 2017
Quoting 27. SteveGregory:



Not much (faith) - though it depends on what type of forcing mechanisms are at work.

To some extent, the atmosphere is still in La Nina mode while SST's are not. (As I mentioned months ago - with the atmosphere in La Nina mode - it could lead to a very active severe WX season - which so far, it has). In fact, there is a 'mini' El Nino near the SOAMER-C.A. coasts (just look at the massive flooding in Peru lately - a typical result of an El Nino). In addition - SSTs remain elevated over the WPAC while they are now near or below normal across the Northern PAC and especially GOA! (The 'blob is gone!) And model forecasts continue to forecast warming SST's in the EPAC over the coming months.

I suspect these strong but conflicting signals from the KEY forcing region is causing the flip-flops in the CPC (and other) long range forecasts. This isn't helped by the fact that the spring season is typically a period of poor model performance.

I will be out of town for the next 2 weeks and don't expect to post to the new blog system until mid APR. But with the changeover to a 'unified' blog (CAT6), I'm not too confident that we can have much back-and-forth discussion like we have been able to do here since the CAT6 blog routinely gets hundreds of daily posts. But we'll see how it plays out.

Steve


thanks
Member Since: December 31, 1969 Posts: Comments:
27. Steve Gregory , Sr. Forecaster/Risk Analysis
2:23 PM GMT on March 24, 2017
Quoting 23. SlabTown:



Hi Steve. How much faith do you put in the CPC long range ? I have literally seen them do a total flip flop from one day to the next for basically the same time period. Thanks


Not much (faith) - though it depends on what type of forcing mechanisms are at work.

To some extent, the atmosphere is still in La Nina mode while SST's are not. (As I mentioned months ago - with the atmosphere in La Nina mode - it could lead to a very active severe WX season - which so far, it has). In fact, there is a 'mini' El Nino near the SOAMER-C.A. coasts (just look at the massive flooding in Peru lately - a typical result of an El Nino). In addition - SSTs remain elevated over the WPAC while they are now near or below normal across the Northern PAC and especially GOA! (The 'blob is gone!) And model forecasts continue to forecast warming SST's in the EPAC over the coming months.

I suspect these strong but conflicting signals from the KEY forcing region is causing the flip-flops in the CPC (and other) long range forecasts. This isn't helped by the fact that the spring season is typically a period of poor model performance.

I will be out of town for the next 2 weeks and don't expect to post to the new blog system until mid APR. But with the changeover to a 'unified' blog (CAT6), I'm not too confident that we can have much back-and-forth discussion like we have been able to do here since the CAT6 blog routinely gets hundreds of daily posts. But we'll see how it plays out.

Steve
Member Since: December 31, 1969 Posts: Comments:
26. 1976Forty2016
6:57 PM GMT on March 19, 2017
Speaking on the CPC from NOAA. It looks like the latest is for much above normal temps in the East in the April-June period, actually a lot of the country much above normal, except for the Pacific Northwest, where normal temps are favored. And as somebody who lives in the PACNW, normal would be preferred, even well into summer. After 3 extremely hot summers in a row, it would be nice to be on the cool side (which is still 80s where I live, not the 90-100 it has been in 14-15-16). I hope the heat doesn't spike for those who live in the East way too early as that can get uncomfortable having well above average for months and months in a row. Last thing, for those of you who may or may not know, search Youtube for a guy named Joe Cioffi. He does daily weather videos for the NE, and also looks at the lower 48 in his videos as well. Very intelligent and thoughtful videos on the weather.
Member Since: December 31, 1969 Posts: Comments:
25. Lawson84
10:54 PM GMT on March 15, 2017
Same as the last 2 comments, I've also noticed the recent changes in the CPC long range and came here to see what's going on. Your excellent analysis is greatly missed at times like this, as I'm sure something interesting is happening with conflicting model signals and large scale pattern changes.
As a gardener in the midwest, the recent warmth has been great. My hope is to get a cold wave out of the way during the rest of March and then we can shift to a Warm East pattern again for early/mid April and any cold waves after that won't be sufficient to kill off the fruit buds and early veggies.

Hope all is well and that the new blog system will work better than the last "new blog system".
Member Since: December 31, 1969 Posts: Comments:
24. Eastcoldwesthot
10:44 PM GMT on March 15, 2017
Oklahoma Kansas warm, East cold, nothing surprising here
Member Since: December 31, 1969 Posts: Comments:
23. SlabTown
11:37 AM GMT on March 15, 2017
Quoting 22. Peekay2016:

Hey Steve,
I can't wait until April 3rd and see your blog. Looking at the CPC long range, I see the cold over the Eastern US retreating substantially towards the end of the month. What is your take of when it will warm up here in the East. I loved the Spring in February. Hope all is well.

Cheers,

Peekay :)


Hi Steve. How much faith do you put in the CPC long range ? I have literally seen them do a total flip flop from one day to the next for basically the same time period. Thanks
Member Since: December 31, 1969 Posts: Comments:
22. Peekay2016
2:45 AM GMT on March 15, 2017
Hey Steve,
I can't wait until April 3rd and see your blog. Looking at the CPC long range, I see the cold over the Eastern US retreating substantially towards the end of the month. What is your take of when it will warm up here in the East. I loved the Spring in February. Hope all is well.

Cheers,

Peekay :)
Member Since: December 31, 1969 Posts: Comments:
21. georgevandenberghe
4:02 PM GMT on March 13, 2017
Quoting 20. SteveGregory:



Oh, you evidently missed spring in FEB. LoL!

Should see significant 'warming' starting next week (no promises - especially around the Great Lakes) - but certainly looks like a wet pattern across most of US east of the Rockies too - fairly 'normal' for late MAR on into APR.

Just had our first sig snowfall here in Chicago in nearly 3 months! (2.2" or so overnight- though some localized areas may get a pretty hefty Lake FEffect snow tonight into tommorrow.

Steve.


gonna do a lot better than 3" in much of the DC metro area tonight and tomorrow. We could really use the water. It has been extremely dry in the Mid Atlantic since late January. Current weekend cold outbreak 3/10-12
was a little warmer than I expected, not sure why but it's spared the cherry blossoms.. so far. Perhaps trajectories over 300 miles of ground that is usually snow covered but not this time, helped.

That won't save us with the next polar or arctic (haven't looked at the airmass to determine) outbreak Wednesday.

Member Since: December 31, 1969 Posts: Comments:
20. Steve Gregory , Sr. Forecaster/Risk Analysis
2:48 PM GMT on March 13, 2017
Quoting 19. SlabTown:



Hi Steve. I am looking forward to your posts. In the meantime do you have any thoughts as to when spring will arrive in the midwest ? thanks


Oh, you evidently missed spring in FEB. LoL!

Should see significant 'warming' starting next week (no promises - especially around the Great Lakes) - but certainly looks like a wet pattern across most of US east of the Rockies too - fairly 'normal' for late MAR on into APR.

Just had our first sig snowfall here in Chicago in nearly 3 months! (2.2" or so overnight- though some localized areas may get a pretty hefty Lake FEffect snow tonight into tommorrow.

Steve.
Member Since: December 31, 1969 Posts: Comments:
19. SlabTown
12:51 PM GMT on March 13, 2017
Quoting 18. SteveGregory:



DAILY UPDATE:

cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIV AR/ALL_emean_phase_full.gif

ALSO:
NO NEW BLOGS UNTILTHE NEW BLOG SYSTEM GOES ONLINE APRIL 3. (I will post under the Category6 - though unsure of my 'schedule' for posts.

Steve


Hi Steve. I am looking forward to your posts. In the meantime do you have any thoughts as to when spring will arrive in the midwest ? thanks
Member Since: December 31, 1969 Posts: Comments:
18. Steve Gregory , Sr. Forecaster/Risk Analysis
9:05 PM GMT on March 11, 2017
Quoting 16. WU-691642:

Steve, Why is there no readily available info on the current position and amplitude of the MJO?


DAILY UPDATE:

cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIV AR/ALL_emean_phase_full.gif

ALSO:
NO NEW BLOGS UNTILTHE NEW BLOG SYSTEM GOES ONLINE APRIL 3. (I will post under the Category6 - though unsure of my 'schedule' for posts.

Steve
Member Since: December 31, 1969 Posts: Comments:
17. Alan8156
2:07 AM GMT on March 11, 2017
"...while the most recent model runs have trended towards a mean TROF across the western interior with strong short waves ejecting towards the northeastern US."

Bingo!
Member Since: December 31, 1969 Posts: Comments:
16. WU-691642
1:22 AM GMT on March 11, 2017
Steve, Why is there no readily available info on the current position and amplitude of the MJO?
Member Since: December 31, 1969 Posts: Comments:
15. WU-691642
12:34 AM GMT on March 11, 2017
Hi, As I try to learn about the MJO I've found almost no info on "the current position and amplitude of any MJO envelope. Why?
Member Since: December 31, 1969 Posts: Comments:
14. Steve Gregory , Sr. Forecaster/Risk Analysis
9:01 PM GMT on March 01, 2017
Quoting 13. Alan8156:



Steve - could the events you describe above also lead to an El Nino?



Strong MJO tend to initiate strong, westerly wind bursts (over the tropical WPAC) and these in turn are often associated with the development of El Nino.

Steve
Member Since: December 31, 1969 Posts: Comments:
13. Alan8156
5:09 PM GMT on February 28, 2017
Quoting 7. SteveGregory:



The MJO and a secondary area of tropical forcing over the ATL(!)

The MJO is forecast to re-intensify as it moves eastward across the Indian Ocean and towards the WPAC again - potentially setting up the milder PAC flow into NORAMER during the second half of MAR. Combined with seasonality suggests the highly progressive and 'westerly flow' type pattern will dominate again in MAR.

It's been noted that an unusually strong area of tropical forcing - similar to an enhanced MJO effect - has appeared at times lately in the eastern ATL. Similar type forcing in past years has evidently resulted in relatively warm spring seasons. But this is not yet a certainty by any means.

Steve


Steve - could the events you describe above also lead to an El Nino?
Member Since: December 31, 1969 Posts: Comments:
12. Steve Gregory , Sr. Forecaster/Risk Analysis
10:21 PM GMT on February 27, 2017
Quoting 11. georgevandenberghe:



How do you feel about the use of "crazy" as an adverb?


Although Steve is spot on that the Pacific SST patterns strongly modulate North American cool season temperatures, I am also starting to wonder what a GOM at "record warm" levels might do to spring and summer temperatures and precipitation patterns.. just a speculative question with no knowledge behind it.
snip



In general, the warmer than normal SST's represent an above 'normal' source of warm, moisture-laden air. Theoretically, everything else being equal, this would in turn support heavier Precip events and arguably stronger
T-storms.

As an aside, It's unlikely that record warm SST's in the GOM will persist thru the summer as the current record anomalies in the GOM are more the result of the persistently warm air Temps this winter than a widespread 'deep pool' of unusually warm ocean.

Steve
Member Since: December 31, 1969 Posts: Comments:
11. georgevandenberghe
3:51 PM GMT on February 27, 2017
Quoting 9. gsytch:

I am sorry, It is recede. I know, the spelling police. I cannot help but to do it. I teach 8th grade.


How do you feel about the use of "crazy" as an adverb?


Although Steve is spot on that the Pacific SST patterns strongly modulate North American cool season temperatures, I am also starting to wonder what a GOM at "record warm" levels might do to spring and summer temperatures and precipitation patterns.. just a speculative question with no knowledge behind it.

Been very DRY in the Mid Atlantic especially this February. I could really use some rain although on Saturday one
of my rental gardens got a good thunderstorm. Talking about getting lucky with local thunderstorms in February is itself unusual in the Mid Atlantic!
Member Since: December 31, 1969 Posts: Comments:
10. Steve Gregory , Sr. Forecaster/Risk Analysis
2:13 PM GMT on February 27, 2017
Quoting 8. Emwhy:

I love early spring weather, but the warm-up of March 2012 created problems here in the northeast as it started the growing season prematurely. A lot of fruit trees bloomed early and then lost their crop when things dipped drastically in April that year.

Steve it's been discussed a lot of the influence of the blob in the NPAC for the winters of '13,'14, and especially '15 on the eastern half of the US and those extreme arctic outbreaks that lasted for weeks. Could the high ssts in the Gulf of Mexico be having a major influence in an opposite way on the eastern half of the country this year?


The warmer Temps in the GOM/off the SE US coast etc no doubt has had some influence on the global pattern - 'tending' towards an opposite outcome compared to the NE PAC 'Blob'. HOWEVER, I doubt it has had anywhere near the impact on our NORAMER winter Temps that the warm Pacific warm 'blob' did. (Which I should add, has not exactly been proven - it's been suggested that actually, the warm SST's in the tropical WPAC had a bigger influence than the 'blob' did on its own.)

In general - Pacific SST anomaly patterns have been shown to have a much bigger impact on our winter weather than ATL based anomalies.

Steve
Member Since: December 31, 1969 Posts: Comments:
9. gsytch
11:19 AM GMT on February 26, 2017
I am sorry, It is recede. I know, the spelling police. I cannot help but to do it. I teach 8th grade.
Member Since: December 31, 1969 Posts: Comments:
8. Emwhy
8:09 PM GMT on February 22, 2017
I love early spring weather, but the warm-up of March 2012 created problems here in the northeast as it started the growing season prematurely. A lot of fruit trees bloomed early and then lost their crop when things dipped drastically in April that year.

Steve it's been discussed a lot of the influence of the blob in the NPAC for the winters of '13,'14, and especially '15 on the eastern half of the US and those extreme arctic outbreaks that lasted for weeks. Could the high ssts in the Gulf of Mexico be having a major influence in an opposite way on the eastern half of the country this year?
Member Since: December 31, 1969 Posts: Comments:
7. Steve Gregory , Sr. Forecaster/Risk Analysis
7:45 PM GMT on February 22, 2017
Quoting 2. SlabTown:

Hi Steve. What are the "SOME indications" that point to possible warmer temps later on ? Thanks.


The MJO and a secondary area of tropical forcing over the ATL(!)

The MJO is forecast to re-intensify as it moves eastward across the Indian Ocean and towards the WPAC again - potentially setting up the milder PAC flow into NORAMER during the second half of MAR. Combined with seasonality suggests the highly progressive and 'westerly flow' type pattern will dominate again in MAR.

It's been noted that an unusually strong area of tropical forcing - similar to an enhanced MJO effect - has appeared at times lately in the eastern ATL. Similar type forcing in past years has evidently resulted in relatively warm spring seasons. But this is not yet a certainty by any means.

Steve
Member Since: December 31, 1969 Posts: Comments:
6. Steve Gregory , Sr. Forecaster/Risk Analysis
7:29 PM GMT on February 22, 2017
Quoting 4. ACSeattle:

The heating degree data is the same for both forecast maps. It looks like the week 2 heating degree forecast appears twice.


Thanks all for the heads-up. Having an issue with no images being updated on the WU at all right now, but will try as soon as possible.

Steve
Member Since: December 31, 1969 Posts: Comments:
5. SlabTown
7:05 PM GMT on February 22, 2017
Hi Steve. I was wondering which of these Midwest warm ups was more remarkable, the most recent or the one in march of 2012. I know the march 2012 had MUCH warmer temps but that was also a few weeks later. Enjoying -looks like temporarily- the warmth in northern michigan. thanks
Member Since: December 31, 1969 Posts: Comments:
4. ACSeattle
10:24 PM GMT on February 21, 2017
The heating degree data is the same for both forecast maps. It looks like the week 2 heating degree forecast appears twice.
Member Since: December 31, 1969 Posts: Comments:
3. georgevandenberghe
10:05 PM GMT on February 21, 2017
Both week graphs are labeled "week 2". Content looks accurate though
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2. SlabTown
8:26 PM GMT on February 21, 2017
Hi Steve. What are the "SOME indications" that point to possible warmer temps later on ? Thanks.
Member Since: December 31, 1969 Posts: Comments:
1. pattywu1
7:58 PM GMT on February 21, 2017
The word "recede" is not spelled "receed" as in your headline.
Member Since: December 31, 1969 Posts: Comments:

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