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Medium Range-Long Range thread


NaoPos

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The upcoming late March-early April period has certain global characteristics setting up for when you have to watch for tornado outbreaks in the mid-section of the nation. Yes, I know... #climo... lol

1. AAM on the decline with remnant STJ

2. Active Atlantic sector/enhanced KW period ends with forcing shifting across IO-Indonesia

3. Rapidly rising AO / lingering -NAO after following very deep -AO min

Models keying in on a couple of robust waves that transverse the southern CONUS during this period. For us, it means more of the same but it could kick off tornado season nicely for our friends in the southern Plains-Mississippi Valley-Gulf/TN valley.

The next period for this combination could be mid-late May which may see another peak in severe weather/tornadic activity.

Given what the current active KW period is capable of and given the possibility of ENSO warming further, it is possible we see a very early season Atlantic tropical wave mid May or so...but I'm not confident. Mid June-early July would be the next enhanced period in the Atlantic.

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The upcoming late March-early April period has certain global characteristics setting up for when you have to watch for tornado outbreaks in the mid-section of the nation. Yes, I know... #climo... lol

1. AAM on the decline with remnant STJ

2. Active Atlantic sector/enhanced KW period ends with forcing shifting across IO-Indonesia

3. Rapidly rising AO / lingering -NAO after following very deep -AO min

Models keying in on a couple of robust waves that transverse the southern CONUS during this period. For us, it means more of the same but it could kick off tornado season nicely for our friends in the southern Plains-Mississippi Valley-Gulf/TN valley.

The next period for this combination could be mid-late May which may see another peak in severe weather/tornadic activity.

Given what the current active KW period is capable of and given the possibility of ENSO warming further, it is possible we see a very early season Atlantic tropical wave mid May or so...but I'm not confident. Mid June-early July would be the next enhanced period in the Atlantic.

Great stuff, HM. I'm still grumpy.

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Great stuff, HM. I'm still grumpy.

 

Thanks and lol. You figure toward the 10th of April, we will get some nice spring weather. haha...

We still have a good 2-3 weeks of -NAO nonsense. 

 

Agreed. Can't wait for some April snow.

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The upcoming late March-early April period has certain global characteristics setting up for when you have to watch for tornado outbreaks in the mid-section of the nation. Yes, I know... #climo... lol

1. AAM on the decline with remnant STJ

2. Active Atlantic sector/enhanced KW period ends with forcing shifting across IO-Indonesia

3. Rapidly rising AO / lingering -NAO after following very deep -AO min

Models keying in on a couple of robust waves that transverse the southern CONUS during this period. For us, it means more of the same but it could kick off tornado season nicely for our friends in the southern Plains-Mississippi Valley-Gulf/TN valley.

The next period for this combination could be mid-late May which may see another peak in severe weather/tornadic activity.

Given what the current active KW period is capable of and given the possibility of ENSO warming further, it is possible we see a very early season Atlantic tropical wave mid May or so...but I'm not confident. Mid June-early July would be the next enhanced period in the Atlantic.

 

 

  

Thanks and lol. You figure toward the 10th of April, we will get some nice spring weather. haha...

 

Agreed. Can't wait for some April snow.

 

GFS is blowing up with convection parameterization issues with the early April storm... but I do think there's a good shot of severe weather for the region you are speaking with regards to! Just wanted to comment on the active KWs over the WH. During times when the MJO is active over the Atlantic sector, we usually get strong CCKWs over the Atlantic and Africa.

 

vp200.GFS.anom.MJO.5S-5N.png

 

 

Atlantic CCKWs in TRMM 3b42:

 

Atlantic.Filtanomrain.30.5S-5N.png

 

 

 

Quick comment about Atlantic TC stuff: If we get an early season TC, usually good indicator that the season wil be anomalously active!  Although while I think the season will be active, worried about a few things with regards to the Pacific. The -NAO for March indicates warmer SSTs over the MDR... warm Nov-Dec SSTs within the Gulf of Guinea during Nov-Dec usually follow with a year characterized by a stronger than average Atlantic cold tongue = westward shift in mean Atlantic genesis away from African continent. Going to be an interesting year, I think GOM could get a couple hits, as well as increased chances for FL.

 

Oh and a quick FYI: If ESRL page dies again as it has been on its way out the door, I know Nick Schiraldi from UAlbany is rebuilding GWO stuff on his site, as well as I have built the GWO with an appended GFS op forecast :)

 

AAM.png

 

 

I like your warmth for NE towards end of second week in April! Paul Roundy's statistical analysis has been keying on a nice warm up for the past couple of weeks:

http://www.atmos.albany.edu/facstaff/roundy/waves/analogs/analogsT.html

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Woah Mike, I didn't see your post. Thanks for the thoughts. After I take a look at things I'll post an update about April.

Seems like we got a nice combo of signals building for a mid April turn-around:

1. Final warming +AO response before reaching lower strat should occur then

2. Tropical forcing/Roundy guidance/AAM-GWO

3. Analogs

There are some years where we see a transition from cold/wet to near record warmth/90s like April 15-20...particularly in developing warm ENSO.

For now, I'm sticking with the potential for 80s.

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I think everyone is on board with the warmth mid-April. Thankfully. Unlike my busted late Feb-early Mar call.

 

Yeah, I think there is a nice agreement among everyone. I always get worried about the -NAO signal lingering this time of year, especially if we don't get a classic final warming response (if you get constant bottom-up mid to upper strat warmings instead of a 1 mb down warming, you won't see a true +AO period -20 days before FW). This would keep the Northeast / Mid Atlantic out of the best warmth, but I'm leaning against that for now (eek).

 

Clicking my ruby slippers together and chanting "let it be green by early may, let it be green by early may, let it be green by early may..."

 

:lol:

Will May 2013 go the way of the last few? Tough call...

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Finally!! Some good news to read on this site!

 

 

Woah Mike, I didn't see your post. Thanks for the thoughts. After I take a look at things I'll post an update about April.

Seems like we got a nice combo of signals building for a mid April turn-around:

1. Final warming +AO response before reaching lower strat should occur then
2. Tropical forcing/Roundy guidance/AAM-GWO
3. Analogs

There are some years where we see a transition from cold/wet to near record warmth/90s like April 15-20...particularly in developing warm ENSO.

For now, I'm sticking with the potential for 80's

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Woah Mike, I didn't see your post. Thanks for the thoughts. After I take a look at things I'll post an update about April.

Seems like we got a nice combo of signals building for a mid April turn-around:

1. Final warming +AO response before reaching lower strat should occur then

2. Tropical forcing/Roundy guidance/AAM-GWO

3. Analogs

There are some years where we see a transition from cold/wet to near record warmth/90s like April 15-20...particularly in developing warm ENSO.

For now, I'm sticking with the potential for 80s.

 

A lot of years where we've had long stretches of sh**ty weather in March result in a fast, furious warmup in mid April.  '03 (until the backdoor from hell), '05, '04, and '01 to name a few in recent years.

 

80-85 is definitely doable...

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A lot of years where we've had long stretches of sh**ty weather in March result in a fast, furious warmup in mid April.  '03 (until the backdoor from hell), '05, '04, and '01 to name a few in recent years.

 

80-85 is definitely doable...

Yes, you are correct. This year will probably not be as stark as the last couple where we can precisely draw the line between "spring and winter." Mid-April probably grows, as expected in any year, volatile during the transition and I wouldn't even rule out snow in the first half of the month.

The lingering -NAO / bottom-up wave response in the stratosphere on the heels of the January SSW/-QBO descent, will not stop until something substantial ends it. A combination of the initial +AO response from the final warming and favorable Indonesian Forcing (how strong will this get is actually debatable) could work together to bring us an exceptionally warm period. At the very least, it will end this ridiculous pattern.

If either one of them fail, time incorrectly or don't happen at all...well... :(

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how do these warming enso's fair in terms of preciptation outlooks? this part of forecasting in not my niche.

Well, this isn't an easy question. How fast the ENSO comes on and its combination with things like the AMO/PDO, for example, influence warm season precipitation. What you can certainly expect is a gradual increase in the southern stream influence late summer / autumn with building wet anomalies across the South and ultimately eastern US.

The PDO/AMO influence lately has made for a wet spring across the Mississippi Valley-Lakes-Appalachians and portions of the Southeast during a developing warm ENSO. The Northeast isn't dry and tends to come out normal to above normal April-May and then very wet in June.

Things like oceanic kelvin waves and intraseasonal variability play a significant role, as always, with precipitation distribution and peaks in STJ intensity. This can skew the spring months around some before a steadier STJ takes over in the late summer/autumn.

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