Winter 2015-2016 Medium-Term Discussion

[WXeastern]

Is there a reason that 97-98 is not in that list?

 

 

Out of the 5 Ninos thats considered strong on record (this one not counted yet). On average 4 had positive AO/EPO values during the month of December.

[tim]

 

I used the word "often" because the sample size is small. One can't be too certain. Below are some composite 500 mb and surface temperature anomalies (January):

 

 

...don,looking at the anomalies maps you posted in re: to SOI drop it doesn't seem to help

the east coast in regard to colder temps..this coming from an 'untrained' eye..

[donsutherland1]

...don,looking at the anomalies maps you posted in re: to SOI drop it doesn't seem to help

the east coast in regard to colder temps..this coming from an 'untrained' eye..

One would need to look for blocking (EPO and/or AO) before one winds up with cold anomalies in the East.But even the above idea argues against a continuation of the extreme warmth that has prevailed through much of December.

[donsutherland1]

More hints of at least a pattern relaxation…

 

If one looks at the latest run of the GFS ensembles, one finds more evidence that ridging is forecast to develop in the West and the pattern responsible for the extreme warmth in the eastern half of North America is poised to relax.

 

Below are charts showing a comparison of the composite anomalies for extreme warmth during the second half of December and the 12/22/2015 0z run of the GFS ensembles at 48 hours.

 

Afterward, the 500 mb height anomalies for 240 hours and 360 hours are posted.

 

 

In sum, it now appears very likely that the pattern will relax in the extended range. The major question is whether the relaxation will prove temporary or a stage along the way toward a pattern change that will provide for more persistent cold across the section of North America that has experienced excessive warmth.

[donsutherland1]

If one examines the latest monthly forecast from the CFSv2 for January, one might be tempted to believe that the traces of summer than have lingered throughout December to date might never be purged fully from North America. Yet, there continue to be increasing hints of a changing pattern.

 

1. The PNA is forecast to go positive.

2. Even as there remains poor run-to-run continuity regarding the EPO and disagreement among the guidance, it does appear that the EPO will at least go neutral in the extended range.

 

Both those developments should be sufficient to relax the predominant pattern responsible for December's abnormal warmth.

 

If one looks further at the GFS ensemble trimmed objective analog pool, taking into consideration, ENSO, one finds that the cases rolled forward for January would yield a different pattern. The northern tier of the CONUS would remain generally warmer than normal, as would much of Canada. However, there would also be a large area of near normal anomalies, as well.

 

Furthermore, the 11-15 day mean 500 mb pattern seems to offer a hint of the predominant pattern suggested by the latest GFS ensemble objective analog pool rolled forward for January.

 

At this point, even as one should not take the numbers literally (e.g., warm anomalies may be more widespread, though they won't rival December's extreme figures) and should be aware that there remains uncertainty, the idea that January will not be a replica of December appears to have reasonable support, even if the CFSv2 remains locked on a much warmer idea.

 

 

[40/70 Benchmark]

If one examines the latest monthly forecast from the CFSv2 for January, one might be tempted to believe that the traces of summer than have lingered throughout December to date might never be purged fully from North America. Yet, there continue to be increasing hints of a changing pattern.

 

1. The PNA is forecast to go positive.

2. Even as there remains poor run-to-run continuity regarding the EPO and disagreement among the guidance, it does appear that the EPO will at least go neutral in the extended range.

 

Both those developments should be sufficient to relax the predominant pattern responsible for December's abnormal warmth.

 

If one looks further at the GFS ensemble trimmed objective analog pool, taking into consideration, ENSO, one finds that the cases rolled forward for January would yield a different pattern. The northern tier of the CONUS would remain generally warmer than normal, as would much of Canada. However, there would also be a large area of near normal anomalies, as well.

 

Furthermore, the 11-15 day mean 500 mb pattern seems to offer a hint of the predominant pattern suggested by the latest GFS ensemble objective analog pool rolled forward for January.

 

At this point, even as one should not take the numbers literally (e.g., warm anomalies may be more widespread, though they won't rival December's extreme figures) and should be aware that there remains uncertainty, the idea that January will not be a replica of December appears to have reasonable support, even if the CFSv2 remains locked on a much warmer idea.

 

 

This idea seems to be lost on some folks.

[donsutherland1]

This idea seems to be lost on some folks.

I suspect that by this time next week, there will be a lot more confidence in that idea. Certainly, this afternoon's guidance does nothing to change my thinking concerning the pattern evolution ahead.

[donsutherland1]

The SOI was up to +30.72 this morning. That's its highest figure since June 13, 2014 when it reached +31.28. This lofty value coincides with an extreme pattern amplification that is currently underway and responsible for record warmth in the East.

 

All of the guidance continues to suggest that decay of the current pattern, which should allow the first week of January to start out with more seasonable temperatures in a large part of the CONUS. The westward location of the Aleutian Low and PNA+ will result in the ridge's being centered in western North America, not eastern North America as has been the case for much of December.

[Wow]

The SOI was up to +30.72 this morning. That's its highest figure since June 13, 2014 when it reached +31.28. This lofty value coincides with an extreme pattern amplification that is currently underway and responsible for record warmth in the East.

 

All of the guidance continues to suggest that decay of the current pattern, which should allow the first week of January to start out with more seasonable temperatures in a large part of the CONUS. The westward location of the Aleutian Low and PNA+ will result in the ridge's being centered in western North America, not eastern North America as has been the case for much of December.

 

This morning's model runs are giving me more confidence the much desired pattern change will indeed occur after the holidays.

[Bob Chill]

Great updates, Don. I've posted about this in the MA sub forum earlier this month. You and I have both looked at the AO behavior quite a bit over the years. December can be quite telling at times when the monthly index is anomalous (at least 1 SD one way or the other). And with this Dec obviously being anomalous in the wrong direction, it does have some bad company with similar Decembers in the past. 

 

However, the duration of anomalous events typically run around 45-60 days. I've only looked at Decembers and forward so I've never really thought about November implications. Theoretically, the currently anomalous period began in November so the end of December could mark the 60 day point. So a breakdown of the strong + phase showing on guidance does fit theory. 

 

 

Of course it could be a simple relaxation and then reload. Similar to what we've seen the last couple years. Or it could possible be the beginning of all out flip. I have my doubts about it but if it were to happen it would be quite similar to 82-83's progression but a few weeks ahead of schedule. 

 

Here's the 82-83 daily graph for DJF:

 

 

If I knew what I knew now back then I would be sick to my stomach during the first week of Jan 83. lol. Quite an anomalous event before the shakeup and then flip. 

 

Looking deeper, the h5 plots for the first half of Jan 83 show a similar pattern to what we are suffering through right now in the high latitudes. Very strong and dominant +AO/NAO combo 

 

 

Pretty abrupt change around the pole during the second half of the month in:

 

 

There are some similarities to what ensemble guidance currently looks like for early Jan. Not a perfect match of course but not terribly different either. 

 

If (the proverbial big IF) the current AO spike is the "last hurrah" then we could potentially be moving into a blocking regime sooner than Feb like what happened in 82-83 but ahead of schedule. Personally, I'm pretty skeptical of that happening but there are some encouraging signs showing up for early Jan. Time will tell. 

[donsutherland1]

Latest 11-15-day 500 mb anomalies (12z GFS ensembles):

 

 

Source: Tropicaltidbits.com

[donsutherland1]

Great updates, Don. I've posted about this in the MA sub forum earlier this month. You and I have both looked at the AO behavior quite a bit over the years. December can be quite telling at times when the monthly index is anomalous (at least 1 SD one way or the other). And with this Dec obviously being anomalous in the wrong direction, it does have some bad company with similar Decembers in the past. 

 

However, the duration of anomalous events typically run around 45-60 days. I've only looked at Decembers and forward so I've never really thought about November implications. Theoretically, the currently anomalous period began in November so the end of December could mark the 60 day point. So a breakdown of the strong + phase showing on guidance does fit theory. 

 

15dailyAO.JPG

 

Of course it could be a simple relaxation and then reload. Similar to what we've seen the last couple years. Or it could possible be the beginning of all out flip. I have my doubts about it but if it were to happen it would be quite similar to 82-83's progression but a few weeks ahead of schedule. 

 

Here's the 82-83 daily graph for DJF:

 

82-83 ao.JPG

 

If I knew what I knew now back then I would be sick to my stomach during the first week of Jan 83. lol. Quite an anomalous event before the shakeup and then flip. 

 

Looking deeper, the h5 plots for the first half of Jan 83 show a similar pattern to what we are suffering through right now in the high latitudes. Very strong and dominant +AO/NAO combo 

 

jan83.JPG

 

Pretty abrupt change around the pole during the second half of the month in:

 

jan832.JPG

 

There are some similarities to what ensemble guidance currently looks like for early Jan. Not a perfect match of course but not terribly different either. 

 

If (the proverbial big IF) the current AO spike is the "last hurrah" then we could potentially be moving into a blocking regime sooner than Feb like what happened in 82-83 but ahead of schedule. Personally, I'm pretty skeptical of that happening but there are some encouraging signs showing up for early Jan. Time will tell. 

Very nice discussion, Bob. To add to your discussion:

 

Of the 14 cases in which December had an AO average of +1.000 or above, 50% saw either January or February (or both) have negative AO averages. The two biggest turnarounds from that sample were 1951-52 (December: +1.987; January-February: -0.654) and 1979-80 (December: +1.295; January-February: -1.519).

 

Having said this, the odds lean somewhat toward an absence of strong monthly blocking (AO average of -1.000 or below). From the above sample, 29% of cases saw either January or February have an AO average of -1.000 or below (just over 7% in January and just over 21% in February). February tended to be somewhat favored (1951-52, 2004-05, 2006-07).

 

Also, from the sample, 29% of cases saw the January-February AO average +1.000 or above and 43% saw it average +0.500 or above. 43% saw the January-February AO average < 0 and 67% of those cases were El Niño winters.

 

21% of cases saw the January-February AO average exceed the December figure (1. 1988-89: December: +1.679; January-February: +3.188); 2. 1992-93: December: +1.627; January-February: +1.924; 3. 1999-00: December: +1.043; January-February: +1.176). However, none of those cases featured El Niño winters.

 

Considering the above information, with a decent degree of uncertainty, my thinking is as follows:

 

1. The January-February AO is very likely to average below the December figure (currently at +1.386).

2. It is very likely that either January or February will see the AO average < 0 (the probabilities favor February).

3. It is somewhat likely that the month that averages < 0 could average -1.000 or below.

4. The AO will likely average > 0 for meteorological winter as a whole.

[Superstorm93]

12z EPS coming in with much higher heights over the Arctic and the trough in the east continues to deepen with this new run. 

 

The weeklies later tonight will be telling on whether or not this pattern holds for a while.

 

(Just a little blocking would be perfect)

 

[donsutherland1]

Select records from December 24, 2015:

 

[donsutherland1]

Did Santa deliver an AO- forecast?

 

That seems to be a reasonable question, even as record high temperatures have again tumbled in parts of the East. The latest GFS ensemble forecast shows the development of an AO-/PNA+ pattern.

 

 

Although the 500 mb pattern evolution differed, winter 1965-66 featured a turnaround following a warm December across much of North America. During January 1966, a series of storms brought increasing snowfall to the East. On January 8, a system dumped 4.3" snow in Boston. Two weeks later as sustained blocking was taking hold, another storm brought 2"-4" snows to such cities as Philadelphia and New York and 8.5" to Boston. January 26-27 saw another storm bring snows that extended farther south into the Middle Atlantic region, including Washington, DC. January 29-31 provided the winter's biggest storm, a blizzard that brought more than a foot of snow to parts of the Middle Atlantic region into Upstate New York.

 

While one should not expect an identical scenario to unfold, the important point is that should the AO-/PNA+ pattern become sustained, there will likely be opportunities for snowfall in a winter that has seen almost none. Perhaps a storm that could bring a swath of snow across New York State into New England during the December 28-29 period offers the first hint of a more promising period ahead.

[leo2000]

 

Did Santa deliver an AO- forecast?

 

That seems to be a reasonable question, even as record high temperatures have again tumbled in parts of the East. The latest GFS ensemble forecast shows the development of an AO-/PNA+ pattern.

 

 

Although the 500 mb pattern evolution differed, winter 1965-66 featured a turnaround following a warm December across much of North America. During January 1966, a series of storms brought increasing snowfall to the East. On January 8, a system dumped 4.3" snow in Boston. Two weeks later as sustained blocking was taking hold, another storm brought 2"-4" snows to such cities as Philadelphia and New York and 8.5" to Boston. January 26-27 saw another storm bring snows that extended farther south into the Middle Atlantic region, including Washington, DC. January 29-31 provided the winter's biggest storm, a blizzard that brought more than a foot of snow to parts of the Middle Atlantic region into Upstate New York.

 

While one should not expect an identical scenario to unfold, the important point is that should the AO-/PNA+ pattern become sustained, there will likely be opportunities for snowfall in a winter that has seen almost none. Perhaps a storm that could bring a swath of snow across New York State into New England during the December 28-29 period offers the first hint of a more promising period ahead.

 

It that a strongly negative AO?. It looks like the EPO will be going negative too which is good and the NAO heading towards neutral. 

[donsutherland1]

It that a strongly negative AO?. It looks like the EPO will be going negative too which is good and the NAO heading towards neutral. 

A number of ensemble members show a strongly negative AO. 

[BuffaloWeather]

LOOKING A LITTLE FARTHER AHEAD...OUR LONG RUN OF RECORD WARMTH IS
ABOUT TO COME TO AN END WITH IMPORTANT CHANGES STARTING TO TAKE
SHAPE IN THE LONGWAVE PATTERN ACROSS THE NORTHERN HEMISPHERE.
SOMEWHAT COLDER AIR WILL BEGIN TO TAKE HOLD ACROSS THE NORTHERN
TIER OF THE UNITED STATES NEXT WEEK WITH SOME SNOW OPPORTUNITIES
HERE IN WESTERN NY. THIS WILL INITIALLY BE DELIVERED BY LOCAL...
RATHER SMALL SCALE CHANGES TO THE FLOW PATTERN DRIVEN BY SYNOPTIC
SYSTEMS.

AS WE HEAD INTO THE FIRST FEW WEEKS OF JANUARY...THE LONGWAVE
HEMISPHERIC PATTERN IS FORECAST TO ADJUST. THE PNA INDEX WILL FLIP
TO POSITIVE...WHICH WILL ALLOW A RIDGE TO BEGIN TO BUILD ALONG THE
WEST COAST AND FORCE A LONGWAVE TROUGH IN THE MEAN TO DEVELOP
ACROSS EASTERN NORTH AMERICA...DIRECTING MORE COLD AIR INTO THE
GREAT LAKES AND NORTHEAST. THE MADDEN JULIAN OSCILLATION /MJO/
WHICH HAS BEEN FAVORING VERY WARM TEMPS IN THE EASTERN US THIS
MONTH...WILL BEGIN TO ORBIT TOWARDS A MORE FAVORABLE PHASE FOR
COLD IN THE EAST BY THE MIDDLE OF JANUARY.

LASTLY...THE VERY STRONG STRATOSPHERIC POLAR VORTEX IS NOW UNDER
PRESSURE FROM UPWARD PROPAGATING ROSSBY WAVES...WHICH ARE FORECAST
TO WEAKEN THE POLAR VORTEX AND CAUSE AT LEAST SOME STRATOSPHERIC
WARMING OVER THE NEXT WEEK TO 10 DAYS. IT IS UNCLEAR YET WHETHER
THIS WILL BE A FULL FLEDGED SUDDEN STRATOSPHERIC WARMING EVENT...
BUT THE WEAKER STRATOSPHERIC POLAR VORTEX SHOULD ALLOW FOR MORE
HIGH LATITUDE BLOCKING TO DEVELOP AS WE GO THROUGH THE FIRST FEW
WEEKS OF JANUARY...WHICH SUPPORTS COLD INTRUSIONS INTO THE GREAT
LAKES AND NORTHEAST.

WITH THE ABOVE IN MIND...EXPECT A NOTABLE TURN TOWARDS MORE
TYPICAL COLD AND SNOW AS WE HEAD INTO JANUARY.

[40/70 Benchmark]

I'm surprised by how many doubts remain regarding the AO.

Still doubters.

[MJO812]

I'm surprised by how many doubts remain regarding the AO.

Still doubters.

Earlier this month, people thought the pattern was not going to change until February.

 

This looks good

[Isotherm]

http://www.lightinthestorm.com/     12/26 Update: Pattern Evolution On Track

 

 

My previous post discussed the potential for tropospheric pattern changes in early January. This largely appears to be on track. The initial change anticipated was the development of more conducive NPAC Geopotential heights. Over the past couple of weeks, we’ve seen the primary inter-seasonal +ENSO forcing cell retrograde westward, while contemporaneously, there has been a gradual dampening of the walker cell induced convective flare-up in the western tropical Pacific. I think this convection has been interfering with the MJO plots, masquerading as a MJO signal. However, the upper divergence plots are not suggestive of a propagating wave at 200hpa, and thus, I am more inclined to believe that a reorientation of the walker cell is promoting increased suppression over the E IO/WPAC and enhancement of convection closer to the international dateline. Further, it is highly unlikely that a MJO wave of the progged amplitude would be present in this very potent El Nino regime.

 

Stratospherically, the prior post discussed the development of a favorable tropospheric precursor pattern earlier in December which would initiate stronger wave activity flux in late December. There is a robust pulse of energy propagating from the troposphere into the stratosphere right now, as evidenced by the recent significant warming of 10hpa temperatures, in addition to improved poleward eddy heat flux. Heat flux has increased to values of approximately 1 standard deviation above normal; however, we are still somewhat early in the stratospheric perturbation process, with much stronger burst(s) of heat flux likely to occur in a couple of weeks.

 

 

 

 

The enhanced wave-1 EP flux will promote the pressing of warmth up against the stratospheric vortex and consequently an elongation, such that the vortex circulation becomes more asymmetrical. This – in concert with variations in ENSO related forcing – will act concurrently to promote increased mid level Geopotential heights over the Western US/NW Canada/Alaska. The PNA (EPO) should turn positive (negative) by the first week of January as a result. Over the next several days, there will be important changes in the northern hemispheric circulation pattern with a transition into a regime which arguably could not be much more conducive for both wave-1/wave-2 forcing. This week’s tropospheric circulation is such that the ridges / troughs are generally destructively interfering with wave-1 and especially wave 2 activity, which is why there will be a transient relaxation in wave activity flux at the end of December / beginning of January. However, the developing tropospheric regime will rapidly increase wave driving such that stratospheric vortex perturbation significantly increases in the second week of January, and should reach a climax around January 20th. I still think that circa January 20th is a reasonable time frame for a potential sudden stratospheric warming event (most likely displacement).

 

 

The zonal mean wind anomalies at 10hpa/65N are progged to decrease significantly in early January, down to more climatological levels. History indicates that vortex intensification usually peaks immediately prior to a rapid deceleration of the mean zonal winds. This forecasted decline, when examined in conjunction with other data, suggests that the stratospheric vortex should continue to weaken in the first half of the month. However, as previously noted, the most robust burst of WAF will likely wait until the middle of month.

 

 

 

Although any sudden stratospheric warming event is still probably at least 3 weeks away, the tropospheric changes occur well prior to that event, as outlined in previous discussions. The reversal of the RNA pattern / -PNA into a predominately +PNA regime is occurring essentially in tandem with similar past El Nino episodes. The PNA in 1977, 1957, and 1965 shifted from negative to positive (in a sustained fashion) in the first week of January. This year should feature that transition around New Year’s Day, which is not unexpected given the available statistics and tropospheric pattern progression.

 

 

The upcoming perturbation of the stratospheric vortex, particularly following increased energy transfer via Geopotential height changes in the eastern hemisphere, should act to weaken the tropospheric vortex, resulting in significant height rises by January 7th. The expectation has been for the neutralization and bias negative of the northern annular mode to begin in the second week of January. This idea is still on track, and current model data supports that notion. Some recent ensemble guidance indicates that the AO could become strongly negative as we approach mid January, which is a possibility, particularly in light of prior similar years. The AO in January 1958 plummeted to around -3 standard deviations near mid month, for example.

 

Going forward, one may wonder if the upcoming regime will feature predominantly dry conditions devoid of the classic El Nino induced sub-tropical jet. Upon examination of prior El Nino’s in which the NPAC pattern shifted from RNA / Western trough to +PNA / Western ridge in January, one will find that there was a significant eastward extension of the sub-tropical jet across the southern/southeastern US. Thus, as the GOAK vortex begins retrograding into the Aleutian Islands for the month of January, I anticipate that the sub-tropical jet will extend further northeast, thereby increasing opportunities for southern stream waves and/or phasing with the northern jet.

 

December 1977/1957/1965:

 

 

 

 

 

January 1958/1966/1978:

 

 

 

The pattern initially, in the beginning of January, may not be one that promotes significant snowfall in the I-95 corridor. Without high latitude blocking in the Arctic/Atlantic, there may not be sufficient backing of the mid/upper level flow to direct short waves along the coast. However, I expect that the rapidly improving Arctic heights, and eventually NAO, should promote increased probabilities for significant coastal snow. Although the magnitude of December’s warmth was historic, the pattern reversal should be quite impressive. The totality of indicators – some of which were alluded to in this discussion – are suggestive of an overall continuation of an active / blocky pattern for the remainder of the meteorological winter, once that pattern fully develops over the course of the next 1-3 weeks.

[DTWXRISK]

Mostly    dumb people 

 

Earlier this month, people thought the pattern was not going to change until February.

 

This looks good

[DTWXRISK]

ISOTHERM

 

    fabulous    outstanding post  -- agree 100%   ...I too think the MJO signal is  somewhat bogus  ( and I  got  caught up into it  as well) 
 QBO is clearly   weakening

[Wow]

Concur with DT. Awesome post Isotherm. Definitely clear our record warm December pattern is coming to an end.

[donsutherland1]

The GFS ensemble's objective analogs include January 1961, January 1981, January 1985, and January 2003, all of which featured some notable cold in the eastern half of North America. While there remains no assurance of genuine Arctic blasts in the near-term, the evolving pattern change should allow for the coldest air so far this season to make it into parts of the U.S. during the first half of January. 

 

FWIW, the trimmed objective analog pool rolled forward to January 15 suggest that below normal temperatures in such cities as Boston, Chicago, Cleveland, Detroit, New York City, Philadelphia, and Washington, DC are somewhat more likely than above normal readings. The main takeaway is that the guidance continues to suggest an end to the extreme warm pattern that had predominated through much of December producing historic warmth in parts of North America.

[40/70 Benchmark]

Pretty in Sync with what we've always expected Dave and Tom.

Oustanding.

[Isotherm]

Thanks for the kind words DT and Wow. Great write-up as well DT. Will be interesting to see how this pattern evolves over the next couple weeks.

[donsutherland1]

Long-Awaited Pattern Evolution Now Underway…

 

The long-awaited pattern regime change from a persistent super ridge centered over eastern North America is now underway. The SOI has now fallen to -23.25 after peaking at +30.72 on December 24. The rate of decline in the ongoing super El Niño has shown some indications of picking up. The most recent weekly changes were as follows:

 

Region 1+2: -0.3°C

Region 3: -0.2°C

Region 3.4: -0.2°C

Region 4: -0.1°C

 

In the larger scale, the kind of historic warmth that covered the eastern half of December during super El Niño events is typically unsustainable, not just in magnitude (otherwise that kind of warmth wouldn’t be such a rare event), but also in coverage. Even as the sample size is limited to two super El Niño cases (1877-78 and 1982-83), super warm winters for the entire December-February period are rare. Hence, with a degree of caution, one can argue that it is more likely than not that the warm anomalies should be expected to retreat to the northern tier (perhaps running from Montana or North Dakota to northern New England and northward) if the current ENSO event is reasonably similar to the two cases and the larger historical experience has relevance. The latest CFSv2 guidance shows just such an outcome.

 

 

The ensembles have persistently been forecasting a return of the PNA+, which is a favored state when the Pacific Decadal Oscillation is positive. More recently, ensemble support for AO- and EPO- blocks has increased. The 12/28/2015 GFS ensembles now show strong agreement that the AO will be falling to negative values with a cluster of members supporting severely negative values during and after the first week in January. Even a few ensemble members support a negative NAO during the extended range.

 

 

At this point, the guidance strongly supports the idea that a pattern evolution is now underway. There will likely be a short lag before the impact of the blocking takes hold on the hemispheric pattern. Before then, there will likely be a transitional pattern that lasts 1-2 weeks. During that transitional pattern, eastern North America will likely be much cooler than during December, even as readings average somewhat above normal in some of the areas that saw extraordinary warmth during December. There may yet be opportunities for systems to cut to the Great Lakes, producing short periods of much warmer than normal readings in the East. The West will generally remain colder than normal, but toward the end of the transitional period, a warming trend may begin to appear in the Pacific Northwest and northwestern Canada on account of the PNA+.

 

What happens afterward will depend on whether the forecast blocking develops. The turnaround that occurred during winter 1965-66 when sustained blocking developed in late January could provide some insight.

[CoastalWx]

Thanks for the kind words DT and Wow. Great write-up as well DT. Will be interesting to see how this pattern evolves over the next couple weeks.

 

I agree with others. A great write-up for sure.

[pcbjr]

I agree with others. A great write-up for sure.

Unfortunately, DT's post seems to have vanished (????)