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Winter 2015-16 Medium-Long Range Discussion


OHweather

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gfs_z500a_namer_27.png

Looks like we'll get our cold starting next weekend. Will we get snow?

 

As far as most of us, probably not (hi climo).

 

And those that do manage to get snow, outside the LES belts, probably won't get much. None of these waves (open / sheared out / positive-tilt) seem particularly moist, nor do they appear to produce a lot of cold sector precip.

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As far as most of us, probably not (hi climo).

And those that do manage to get snow, outside the LES belts, probably won't get much. None of these waves (open / sheared out / positive-tilt) seem particularly moist, nor do they appear to produce a lot of cold sector precip.

In general I agree most of the waves coming out shouldn't do much. We definitely won't be lacking a strong temp gradient so if a stronger wave can make it out into the Plains I wouldn't rule out a swath of decent snow somewhere.
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12z Euro warming up a cutter at day 9.  Couldn't look much more different than the GFS at that time.

The GFS and Euro have both been rather inconsistent with what happens from the 24th-26th. Both models and ensembles have another dump of cold, but whether the cold goes into the Rockies and sparks a cutter or goes into the Midwest and doesn't cause a cutter aren't agreed on. The Euro has perhaps been a bit more consistent in at least hinting at a cutter for the last few runs. I could live without the big cutter but I'm selfish

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Per the Typhoon rule (not sure how familiar people are to this rule on this forum), there should be a western trough digging down sometime between the 21st and 24th, with heights rising in the east. GFS and Euro both have a trough digging down in this time frame, but not in great agreement about the timing. I suspect it's because they disagree about how efficient the Greenland blocking will be. Regardless.... we could be looking at a storm system around Thanksgiving day

 

BXj0kn5.png

nsWWsy9.png

 

tr-fix-cv-02.png

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Per the Typhoon rule (not sure how familiar people are to this rule on this forum), there should be a western trough digging down sometime between the 21st and 24th, with heights rising in the east. GFS and Euro both have a trough digging down in this time frame, but not in great agreement about the timing. I suspect it's because they disagree about how efficient the Greenland blocking will be. Regardless.... we could be looking at a storm system around Thanksgiving day

 

I thought the Typhoon Rule says the trough in the east occurs 6-10 days after the recurve...if the invest in the West Pac develops (which it should) it would recurve in about a week...which actually puts the cold dump in the east around the turn of the month. There's a physical reason the typhoon rule often works, but with the long range ensembles trying to show the polar vortex starting to consolidate again after Thanksgiving and with convection starting to become more active again over the Pacific, I can't help but think we'll start going back to a more typical El Nino pattern for December at some point during the first week of the month.

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Per the Typhoon rule (not sure how familiar people are to this rule on this forum), there should be a western trough digging down sometime between the 21st and 24th, with heights rising in the east. GFS and Euro both have a trough digging down in this time frame, but not in great agreement about the timing. I suspect it's because they disagree about how efficient the Greenland blocking will be. Regardless.... we could be looking at a storm system around Thanksgiving day

 

BXj0kn5.png

 

 

 

 

That trough placement in the east looks too far east gives a blocking high pressure on Greenland's west Coast. If the high keeps on showing up, then I would expect that trough to back up some. Probably end up seeing a more broad trough over the Midwest and Great Lakes, especially if that Alaska ridge builds poleward.

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I thought the Typhoon Rule says the trough in the east occurs 6-10 days after the recurve...if the invest in the West Pac develops (which it should) it would recurve in about a week...which actually puts the cold dump in the east around the turn of the month. There's a physical reason the typhoon rule often works, but with the long range ensembles trying to show the polar vortex starting to consolidate again after Thanksgiving and with convection starting to become more active again over the Pacific, I can't help but think we'll start going back to a more typical El Nino pattern for December at some point during the first week of the month.

That's the essence of the Typhoon rule... but the reason why that rule exists (Typhoon recurves -> cold east US) is because there's a cold front/trough in the vicinity of Japan that forces the Typhoon to steer away from the country. It's been shown that whenever you see a trough in Japan, even if there's no Typhoon, you can bet on a trough in the east US 7-10 days later. When there's a trough over Japan, there's usually a ridge to its west in east Asia (usually Mongolia)... that's when you should expect a west ridge/east trough in the next week. Last November's Typhoon Nuri was a big test for the TR and BSR, and it passed. There were 4 parts to the storm; 2 recurves (Typhoon rule), the bomb in the Bering (Bering sea rule), and the wavebreaking event that happened in the Bering. All 4 parts of the storm favored cold weather throughout most of November.

 

Likewise, if there's a ridge over Japan and a Typhoon doesn't recurve (steers into China or dissipates), then you should expect an eastern ridge. It's not necessarily the Typhoon that you're looking at... it's the pattern over Japan which decides its fate. That's what matters.

 

This application of the TR certainly isn't perfect; it has problems when strong blocking develops, but it's big over on Accuweather's forums where we do this almost regularly and it's very reliable otherwise. I know because I'm among the relatively few that regularly forecasted with the TR last winter. Additionally, 2 frequent posters (Joe Renken, "jdrenken" and Josh Herman, "OSNW3") over there just got a paper published into the 39th NOAA Annual Climate Diagnostics and Prediction Workshop regarding the Typhoon rule and the Bering sea rule. 

 

http://www.nws.noaa.gov/ost/climate/STIP/39CDPW/39cdpw-JRenken.pdf

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That's the essence of the Typhoon rule... but the reason why that rule exists (Typhoon recurves -> cold east US) is because there's a cold front/trough in the vicinity of Japan that forces the Typhoon to steer away from the country. It's been shown that whenever you see a trough in Japan, even if there's no Typhoon, you can bet on a trough in the east US 7-10 days later. When there's a trough over Japan, there's usually a ridge to its west in east Asia (usually Mongolia)... that's when you should expect a west ridge/east trough in the next week.

Likewise, if there's a ridge over Japan and a Typhoon doesn't recurve (steers into China or dissipates), then you should expect an eastern ridge. It's not necessarily the Typhoon that you're looking at... it's the pattern over Japan which decides its fate. That's what matters.

This application of the TR certainly isn't perfect, but it's big over on Accuweather's forums where we do this almost regularly and it's very reliable. I know because I'm among the relatively few that regularly forecasted with the TR last winter. Additionally, 2 frequent posters (Joe Renken, "jdrenken" and Josh Herman, "OSNW3") over there just got a paper published into the 39th NOAA Annual Climate Diagnostics and Prediction Workshop regarding the Typhoon rule and the Bering sea rule. Last November's Typhoon Nuri was a big test for the TR and BSR, and it passed.

http://www.nws.noaa.gov/ost/climate/STIP/39CDPW/39cdpw-JRenken.pdf

I'll have to give the paper a read...I'm familiar with Joe and their research and am glad they got it published. Joe does pop in here on occasion too.

The physical reason behind the TR is the typhoon strengthens the Aleutian low which helps develop a ridge into Alaska...transport of heat north by the typhoon also most likely helps the ridge...which dumps cold into Canada and eventually the U.S. Joe has mentioned to me before a trough over Japan without a typhoon having the same result...and perhaps that's expanded on in the paper...but without a typhoon I can't imagine the correlation is nearly as strong, but a deep trough moving from Japan to the Aleutians can cause an Alaskan ridge on its own if it's deep enough. The GFS ensemble image you posted for 120 hours doesn't show a near deep enough trough over Japan to have the desired affect.

Just quickly thumbing through the op GFS, you can see how the typhoon sets things off in about a week in a manner similar to what I described above.

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I'll have to give the paper a read...I'm familiar with Joe and their research and am glad they got it published. Joe does pop in here on occasion too.

The physical reason behind the TR is the typhoon strengthens the Aleutian low which helps develop a ridge into Alaska...transport of heat north by the typhoon also most likely helps the ridge...which dumps cold into Canada and eventually the U.S. Joe has mentioned to me before a trough over Japan without a typhoon having the same result...and perhaps that's expanded on in the paper...but without a typhoon I can't imagine the correlation is nearly as strong, but a deep trough moving from Japan to the Aleutians can cause an Alaskan ridge on its own if it's deep enough. The GFS ensemble image you posted for 120 hours doesn't show a near deep enough trough over Japan to have the desired affect.

Just quickly thumbing through the op GFS, you can see how the typhoon sets things off in about a week in a manner similar to what I described above.

@bolded.... I don't think that's the TR. That would create an immediate effect on our weather. That's why we saw the western ridge/eastern trough pattern amplify 2-3 days after Typhoon Nuri bombed out. The TR states that the impact will occur in 7-10 days

 

@italicized... it's true that it's probably much better when there's actually a Typhoon that recurves. But I'd much rather apply the TR in the near-term than rely on the 7-10 day forecast from the models. More often than not, you see that the 7-10 day forecast turns into what you were expecting from applying the TR. 

 

The TR runs into problems when there's strong blocking, such as this coming week... so I doubt we're gonna see a 10 day long eastern ridge/western trough like the TR would suggest. I expect it to be more progressive than that. 

 

Anyway... I'll gladly go on record to say that there should be a western trough around the 24th, then it'll come east and present us with a pre-Thanksgiving system to track.

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@bolded.... I don't think that's the TR. That would create an immediate effect on our weather. That's why we saw the western ridge/eastern trough pattern amplify 2-3 days after Typhoon Nuri bombed out. The TR states that the impact will occur in 7-10 days

@italicized... it's true that it's probably much better when there's actually a Typhoon that recurves. But I'd much rather apply the TR in the near-term than rely on the 7-10 day forecast from the models. More often than not, you see that the 7-10 day forecast turns into what you were expecting from applying the TR.

The TR runs into problems when there's strong blocking, such as this coming week... so I doubt we're gonna see a 10 day long eastern ridge/western trough like the TR would suggest. I expect it to be more progressive than that.

Anyway... I'll gladly go on record to say that there should be a western trough around the 24th, then it'll come east and present us with a pre-Thanksgiving system to track.

I agree with your last sentence either way :P

And the bolded is the physical reason the typhoon rule works...and it's not instantaneous as it does take time for cold to get into the U.S. after that series of events occurs (unless the preceeding weather pattern was already cold). I can't expand on this more more as I'm driving into work right now

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I agree with your last sentence either way :P

And the bolded is the physical reason the typhoon rule works...and it's not instantaneous as it does take time for cold to get into the U.S. after that series of events occurs (unless the preceeding weather pattern was already cold). I can't expand on this more more as I'm driving into work right now

Pssh... typing on your phone and driving? Calling the po-po on you :P

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BUF NWS says cold is coming.

 

GENUINE COLD WEATHER HAS BEEN TOUGH TO COME BY SO FAR THIS FALL...
AS THE COMBINATION OF SEVERAL GLOBAL TELECONNECTIONS HAVE GENERALLY
KEPT ANOMALOUSLY COLD AIR LOCKED NORTH OF 60N. A STRONG PACIFIC
JET...TYPICALLY ASSOCIATED WITH STRONG TO MODERATE EL NINO EVENTS...
HAS BEEN THE MOST NOTEWORTHY FACTOR IN BLOCKING ANY SIGNIFICANT COLD
AIR INTRUSIONS UP TO THIS POINT. THIS RESULTED IN NEAR NORMAL
TEMPERATURES FOR THE MONTH OF OCTOBER AND WELL ABOVE NORMAL READINGS
THROUGH THE MIDDLE OF THIS MONTH. THIS PATTERN MAY BE SHOWING SIGNS
OF BREAKING DOWN THOUGH.

 

SIGNIFICANT SNOW COVER ACROSS SIBERIA HAS LIKELY HELPED TO INTENSIFY
THE COLD AIR OVER THAT REGION...AND NOW SEVERAL ENSEMBLE GUIDANCE
PACKAGES ARE SUGGESTING THAT SOME OF THIS COLD AIR MAY SOON BE ON
THE MOVE. AFTER MORE THAN SIX WEEKS OF A PREDOMINANTLY POSITIVE NAO
WITH PERSISTENT LOW PRESSURE OVER THE NORTH ATLANTIC...MEDIUM TO
LONG RANGE GUIDANCE IS SUGGESTING THAT BLOCKING MAY FINALLY SET UP
OVER THAT REGION WHILE WEST COAST RIDGING SETS UP OFF NORTH AMERICA.
THIS WOULD RESULT IN A DEEP TROUGH OVER CENTRAL CANADA THAT WOULD
ENCOURAGE THE AFOREMENTIONED COLD AIR TO CROSS THE NORTHERN
LATITUDES OF THE CONTINENT...POSSIBLY TAKING AIM ON THE U.S. PLAINS.

 

THIS SCENARIO WOULD NOT TAKE PLACE UNTIL LATER THANKSGIVING WEEK OR
THANKSGIVING WEEKEND...BUT IT IS THE FIRST TIME THAT IT IS BEING
STRONGLY SUGGESTED BY SO MANY OF THE VARIOUS ENSEMBLE MEMBERS OF
BOTH THE ECMWF AND GFS. IT WILL BE INTERESTING TO SEE HOW THIS ALL
PANS OUT."

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I agree with your last sentence either way

And the bolded is the physical reason the typhoon rule works...and it's not instantaneous as it does take time for cold to get into the U.S. after that series of events occurs (unless the preceeding weather pattern was already cold). I can't expand on this more more as I'm driving into work right now

Maybe I'm not following here but didn't you say the TR puts the trough in the east? Or does it start in the west then move east? I was under the impression it spurred an Eastern trough.

Sent from my XT1060 using Tapatalk

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Maybe I'm not following here but didn't you say the TR puts the trough in the east? Or does it start in the west then move east? I was under the impression it spurred an Eastern trough.

Sent from my XT1060

I think the idea is it gets cold in the east. I'll have to read the paper on the topic here when I get a little time. I could see how where the cold dumps varies based on other factors such as wavelengths, the proceeding weather pattern and how strong the typhoon is. The TR has been around for a while and JB has mentioned it for years as have other mets, but the paper Cliche posted could be the first true "research" done on it.

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