2016-2017 Great Tennessee Valley Winter Discussion

[AMZ8990]

1 minute ago, John1122 said:

GFS lost the event this morning but is slowly building it back over western areas. Canadian has a full fledged storm but too far north for snow.

I noticed the same thing when I was looking at some maps earlier in the day.  It is starting to creep into west Tennessee on the LR GFS, It's still only showing about an inch or so but at least we have potential for something.  It would not surprise me if the maps lost this piece of energy tomorrow or Sunday only to pick it back up on Monday or Tuesday.  As far as estimated amounts go, they will up and down all week.  I saw what you were talking about on the Canadian maps too, They have Kentucky getting plastered on that map.  

[jaxjagman]

This could  be another severe potential around the 18th give or take in the EAST.Positive tilted trough going into Mongolia and China will pump up the heights into South Korea and into the Sea of Japan.Something to watch anyways and keep an eye on the tele's.

 

 

 

 

 

 

[jaxjagman]

If we were to see these artic highs into N.America in a normal winter,this would have the potential to produce winter

[jaxjagman]

2014	-0.5	-0.5	-0.4	-0.2	-0.1	0.0	-0.1	0.0	0.1	0.4	0.5	0.6
2015	0.6	0.5	0.6	0.7	0.8	1.0	1.2	1.4	1.7	2.0	2.2	2.3
2016	2.2	2.0	1.6	1.1	0.6	0.1	-0.3	-0.6	-0.8	-0.8	-0.8	-0.7

 We have  officially achieved Nina in 2016

[John1122]

00z model suite so far is now a clipper for next Friday, more precip but rain on the GGEM Cold enough for snow on the GFS but after dumping 3-4 inches NW of the area is weakens and drops around an inch or less in East Tennessee. If the ridge in the west would be more west and higher, the system could possibly make some hay, as it is the ridge doesn't cooperate.

[John1122]

Mega +PNA on the GFS at day 10. 

 

GEFS as well.

 

The ENS are showing a +2 PNA. Very rare that it even exceeds +1.5. The following years since 1950 it went very close to or above +1.5.

February 28th 1957 it was +1.5. Stayed positive into March and the first week of March there was a 2-4 inch snow event from Nashville to Knox to Tri.

Jan 7th 1958 +1.49 highs in the 20s and lows near 0 for my area and Crossville with 1-2 inches of snow. BNA, Knox and Tri all report snow for the 7th and 8th.

February 18th 1958 it got to +1.4 and was more than +1 positive for the week from the 11th to the 18th.  Major V-Day snow. 3-4 Nashville area. 8-10 Plateau to Tri. 6-8 in Cha/Tys. Sub zero cold for BNA, CSV, TYS and TRI.

February 28th 1959 it gets to +1.4, high is near 70 across East Tn that day. By March 3rd 1-3 inches of snow fall across the Plateau and NE Tn with snow fall of less than an inch reported in TYS and BNA.

Dec 16th 1960 it gets to +1.4. Highs in the 30s, lows in the 10s with snow showers. Stayed around +1.2 to +1.3 for a week or so. Temps in the 20s and lows in the single digits through that time frame with several more days of snow showers.

Jan 19th 1961 spikes to +1.5 after slowly building for several days. Highs in the upper 50s and low 60s area wide on the 17th and 18th fall off the edge of the ocean. Several inches of snow falls over the next few days across the region 2-4 in the Eastern Valley, 3-6 along the Plateau. highs in the 20s and 30s and lows near 0 that week. It's +1.8 by the 20th, the highest reading between 1950 and 1961. The temp is -5 to -10 over the Plateau and NE Tn, near 0 in the valleys.

February 26th 1963 it gets close to +1.4 after being mildly positive since just before V-Day. There's a massive winter storm as it crosses +1 by the 18th/19th. The week following through the 26th there are 5 days with lows below 5 degrees at CSV and two separate snow events in the +pna event.

December 1963 it turns very +, peaking at +1.4 on the 21st TRI doesn't get above freezing for 6 of the next 8 days with 6 inches of snow falling near Christmas. Similar conditions at BNA and other areas of the state as well.

 

February 20th 1964. Goes to +1.4 at it's peak after being positive most of the month. Crossville records a foot of snow for the month. Temps are -15 to -20 from normal across the state on the 20th and 21st.

March 6th 1965. After being negative most of the winter, the PNA goes + peaking at +1.5 on March 6th. Temps go from the 60s to the 30s and 8 inches of snow falls in Crossville over the next week. 3-6 falls in other areas outside the Plateau.

 

March 29th 1966, after being negative it started positive, peaking at +1.6 on March 29th. On March 21st it was 85 in Nashville.  Temps were -15 from normal for 5 of the next 7 days at BNA after the PNA began to go quickly positive. It was in the mid 10s in Crossville and Tri by the 29th.

February 23rd 1968 saw a +1.7 after a +1.4 on the 22nd. Temp departures were -20 to -25 from normal across the area during this time. It spiked super positive on the 28th and 29th, crossing +2, which is exceptionally rare. Temps were once again around -20 from normal and 2-6 inches of snow fell on the 29th and March 1st in the region.

November 19th 1968 saw it hit +1.5. 1-3 inches of snow fell across the Plateau and NE Tn with temps in the 30s and 10s. A trace fell in valley areas.

December 2nd 1969 it got to +1.6. One of the least wintry spikes of the PNA to this level. Temps were only 10 to 15 degrees below normal. It stayed positive for most of the month though and 10 inches of snow fell along the Plateau.

March 16th 1970. Hit +1.4. Three straight days of snow showery weather with temps 15 to 20 degrees below normal across the region once again.

February 9th 1971 it hits +1.5. Highs in the 10s and lows below 0 area wide. 4-6 inches of snow at BNA/CSV/TYS etc. Nashville is 34 degrees below normal on the 9th after getting 5 inches of snow on the 8th.

It didn't get more than +1.4 for the next 4 years. Late February 1975 if finally got to +1.5. There was at least some snow in the area for 6 of the next 8 days after it hit almost +1.6 on the 26th. It was 15 to 20 degrees below normal the 1st week of March.

February of 1977 was a super + PNA for a good portion of the month, with quite a number of days at +1.4 or higher. 11 of the 28 days saw temps between -12 and -20 degrees from normal. Snow fell 8 days. Mostly a dry month. The PNA went neutral late and temps spiked to near 80. 

February 20-22nd 1978 saw it hit +1.6 three days in a row. Several inches of snow fell in the area and temps were -15 to -21 from normal during that stretch.

 

February 5-7th 1980 the PNA hit +1.5 to +1.7 while being positive the first 13 days of the month. It snow 4-8 inches in the area during this time frame and the warmest day saw temps around 8 degrees below normal, with most being 15 or so below normal. There was a brief secondary spike to +1.6 late month. When that happened the temp went from +17 from norm to -19 from norm 4 days later.

Jan 6th-7th 1981 had another spike to +1.5 with another +1.5 coming around the 22nd. The month was almost wall to wall cold. Sub zero lows happened around the fist spike. Only 4 days were above normal. There were several days of -25 to -30 departures from normal. Snow fell in parts of the area on almost half the days of the month.

March 6th-7th of 1981 saw it hit +1.6. Multiple days of -10 degree departures from norm followed.

December 1981 it went to +1.5 on the 18th. Multiple days in a row of -20 degree departures with a major winter storm on the 21st in the form of freezing rain.

Late February into Early March of 1983 it went super positive +1.5 to +1.8 for almost 2 weeks. Early on we had one or two days of -10 degree departures. Then it was actually very warm for the first week of March, which as you can see from reading so far, that's exceptionally rare here with a spiked PNA. From March 9th through the 12th it spiked again, all the way to +1.9. Temps were 10-15 below normal and there was some snow in that time frame in the area. Overall though, strangely mild stretch of positive PNA.

December 20th 1985 had a +1.6 spike and it stayed positive for several days in a row. Temps were -10 to -20 vs norm over all but 2-3 days the rest of the month.

March 1st 1986 had it hit +1.5. It was -10 to -15 from normal the first week of the month with snow showers in the area.

Outside winter months, but first week of April 1987 saw the rare +2 PNA spike. April 3rd 10-15 inches of snow fell across the East Tn area with temps 20 to 25 below normal

Nov 30th/December 1st 1987 +1.6 was 5-10 below norm the first week of the month with snow showers.

Feb 20th 1988. Got to +1.5. 4 of the next 5 days was -10 to -15 from normal in the area. Out of winter months when spikes are more common, but there was also a spike in mid April that saw -15 to -20 departures and sub freezing lows.

December 1988 saw an early month +1.4 around the 6th with the + lasting until the 18th 14 of those 18 days were below norm. Many 10-15 degrees below. There was a 1-3 inch snow event and several other days of snow showery weather.

December 1989 saw a +2 spike. We know the frigid that unleashed.

Late Feb 1991 saw it hit +1.5 for for a few days around the 26th. Temps were -15 from norm in an otherwise very mild winter.

Peaked at almost +1.4 Jan 19th 1992. Had 5 days of -15 to -25 departures including one day near 0 in another very mild winter.

Spiked again in late Feb/Early March 1993. Winter had been an absolute dud until then. Snowed 2-4 inches late Feb, several snow showery days in early March, then the blizzard.

Hit +1.7 Feb 7th 1995 with several days above 1.5 that week. Snowed 3-6 in the area on the 7th, lows were below 0 on the 8th and 9th with highs in the teens on the 8th.

Big positive spikes basically fled in the late 1990s. Next was February 2000. It went above +1 on the 1st or so, getting to +1.6 on the 5th. Temps were generally around 10 degrees below normal and it snowed several days in a row.

Had a +1.5 peak just after New Years 2001 after being just above +1 in late Dec. Temps -15 to -20 from normal for most of that time frame with several days of snow showers in the mix, something like 9 of 15 days in my area. Lowest lows in the single digits multiple times, lowest highs in the lower 20s multiple times.

December 2001 saw it go to +1.3, peaking at +1.6 in early January. 2 weeks of snow showery weather and temps in the 15 degrees below normal range.

Steady positive through early to mid December 2002, peaking at +1.9 on the 13th before crashing back to neutral in the next few days. The first two weeks of the month were 6-15 degrees below normal on the various days.

Spike to +1.7 in February 2006 that translated into -15 from normal and a 3-6 inch snow event in the area.

December 8th 2006, +1.6. Highs in the upper 20s, lows in the single digits.

Early Jan 2010 got up to 1.4, highs in the 10s, lows in the single digits and snow during the time frame.

Even in dreadful 2012 we had a brief +pna at 1.5 that last for 4 days in mid Feb. Temps were -6, -18, -15 and -12 from normal at CSV those days.

Last February it spike to +1.4 around the 10th and we got the big V-Day storm.

This ended up being a long post that took a while. But the point is, we rarely see PNA spikes approach 2.0. When we do see them go above 1.4 there's a high high chance it will be followed by at the very least, cold weather. Often with precip either in NW flow or in the form a a big storm. The big spikes are far and away more likely to happen in February. But even in April we saw what a spike to 2.0 did in 1987. The above maps may not come to pass, but if they do...good good potential around that time frme regardless of exact threats a model may be showing for now.

 

 

 

 

 

 

 

 

[JayCee]

Impressive post John.  Wow, that took a lot of work and research.  Kudos to you, and thanks for sharing. 

[Coach B]

Most of us know that a +PNA generally leads to cold for our area. But to link it to actual historical data over a long period of time takes it to another level. Thank you John! Fascinating reading. 

[weathertree4u]

2 hours ago, John1122 said:

Mega +PNA on the GFS at day 10. 

 

GEFS as well.

 

The ENS are showing a +2 PNA. Very rare that it even exceeds +1.5. The following years since 1950 it went very close to or above +1.5.

February 28th 1957 it was +1.5. Stayed positive into March and the first week of March there was a 2-4 inch snow event from Nashville to Knox to Tri.

Jan 7th 1958 +1.49 highs in the 20s and lows near 0 for my area and Crossville with 1-2 inches of snow. BNA, Knox and Tri all report snow for the 7th and 8th.

February 18th 1958 it got to +1.4 and was more than +1 positive for the week from the 11th to the 18th.  Major V-Day snow. 3-4 Nashville area. 8-10 Plateau to Tri. 6-8 in Cha/Tys. Sub zero cold for BNA, CSV, TYS and TRI.

February 28th 1959 it gets to +1.4, high is near 70 across East Tn that day. By March 3rd 1-3 inches of snow fall across the Plateau and NE Tn with snow fall of less than an inch reported in TYS and BNA.

Dec 16th 1960 it gets to +1.4. Highs in the 30s, lows in the 10s with snow showers. Stayed around +1.2 to +1.3 for a week or so. Temps in the 20s and lows in the single digits through that time frame with several more days of snow showers.

Jan 19th 1961 spikes to +1.5 after slowly building for several days. Highs in the upper 50s and low 60s area wide on the 17th and 18th fall off the edge of the ocean. Several inches of snow falls over the next few days across the region 2-4 in the Eastern Valley, 3-6 along the Plateau. highs in the 20s and 30s and lows near 0 that week. It's +1.8 by the 20th, the highest reading between 1950 and 1961. The temp is -5 to -10 over the Plateau and NE Tn, near 0 in the valleys.

February 26th 1963 it gets close to +1.4 after being mildly positive since just before V-Day. There's a massive winter storm as it crosses +1 by the 18th/19th. The week following through the 26th there are 5 days with lows below 5 degrees at CSV and two separate snow events in the +pna event.

December 1963 it turns very +, peaking at +1.4 on the 21st TRI doesn't get above freezing for 6 of the next 8 days with 6 inches of snow falling near Christmas. Similar conditions at BNA and other areas of the state as well.

 

February 20th 1964. Goes to +1.4 at it's peak after being positive most of the month. Crossville records a foot of snow for the month. Temps are -15 to -20 from normal across the state on the 20th and 21st.

March 6th 1965. After being negative most of the winter, the PNA goes + peaking at +1.5 on March 6th. Temps go from the 60s to the 30s and 8 inches of snow falls in Crossville over the next week. 3-6 falls in other areas outside the Plateau.

 

March 29th 1966, after being negative it started positive, peaking at +1.6 on March 29th. On March 21st it was 85 in Nashville.  Temps were -15 from normal for 5 of the next 7 days at BNA after the PNA began to go quickly positive. It was in the mid 10s in Crossville and Tri by the 29th.

February 23rd 1968 saw a +1.7 after a +1.4 on the 22nd. Temp departures were -20 to -25 from normal across the area during this time. It spiked super positive on the 28th and 29th, crossing +2, which is exceptionally rare. Temps were once again around -20 from normal and 2-6 inches of snow fell on the 29th and March 1st in the region.

November 19th 1968 saw it hit +1.5. 1-3 inches of snow fell across the Plateau and NE Tn with temps in the 30s and 10s. A trace fell in valley areas.

December 2nd 1969 it got to +1.6. One of the least wintry spikes of the PNA to this level. Temps were only 10 to 15 degrees below normal. It stayed positive for most of the month though and 10 inches of snow fell along the Plateau.

March 16th 1970. Hit +1.4. Three straight days of snow showery weather with temps 15 to 20 degrees below normal across the region once again.

February 9th 1971 it hits +1.5. Highs in the 10s and lows below 0 area wide. 4-6 inches of snow at BNA/CSV/TYS etc. Nashville is 34 degrees below normal on the 9th after getting 5 inches of snow on the 8th.

It didn't get more than +1.4 for the next 4 years. Late February 1975 if finally got to +1.5. There was at least some snow in the area for 6 of the next 8 days after it hit almost +1.6 on the 26th. It was 15 to 20 degrees below normal the 1st week of March.

February of 1977 was a super + PNA for a good portion of the month, with quite a number of days at +1.4 or higher. 11 of the 28 days saw temps between -12 and -20 degrees from normal. Snow fell 8 days. Mostly a dry month. The PNA went neutral late and temps spiked to near 80. 

February 20-22nd 1978 saw it hit +1.6 three days in a row. Several inches of snow fell in the area and temps were -15 to -21 from normal during that stretch.

 

February 5-7th 1980 the PNA hit +1.5 to +1.7 while being positive the first 13 days of the month. It snow 4-8 inches in the area during this time frame and the warmest day saw temps around 8 degrees below normal, with most being 15 or so below normal. There was a brief secondary spike to +1.6 late month. When that happened the temp went from +17 from norm to -19 from norm 4 days later.

Jan 6th-7th 1981 had another spike to +1.5 with another +1.5 coming around the 22nd. The month was almost wall to wall cold. Sub zero lows happened around the fist spike. Only 4 days were above normal. There were several days of -25 to -30 departures from normal. Snow fell in parts of the area on almost half the days of the month.

March 6th-7th of 1981 saw it hit +1.6. Multiple days of -10 degree departures from norm followed.

December 1981 it went to +1.5 on the 18th. Multiple days in a row of -20 degree departures with a major winter storm on the 21st in the form of freezing rain.

Late February into Early March of 1983 it went super positive +1.5 to +1.8 for almost 2 weeks. Early on we had one or two days of -10 degree departures. Then it was actually very warm for the first week of March, which as you can see from reading so far, that's exceptionally rare here with a spiked PNA. From March 9th through the 12th it spiked again, all the way to +1.9. Temps were 10-15 below normal and there was some snow in that time frame in the area. Overall though, strangely mild stretch of positive PNA.

December 20th 1985 had a +1.6 spike and it stayed positive for several days in a row. Temps were -10 to -20 vs norm over all but 2-3 days the rest of the month.

March 1st 1986 had it hit +1.5. It was -10 to -15 from normal the first week of the month with snow showers in the area.

Outside winter months, but first week of April 1987 saw the rare +2 PNA spike. April 3rd 10-15 inches of snow fell across the East Tn area with temps 20 to 25 below normal

Nov 30th/December 1st 1987 +1.6 was 5-10 below norm the first week of the month with snow showers.

Feb 20th 1988. Got to +1.5. 4 of the next 5 days was -10 to -15 from normal in the area. Out of winter months when spikes are more common, but there was also a spike in mid April that saw -15 to -20 departures and sub freezing lows.

December 1988 saw an early month +1.4 around the 6th with the + lasting until the 18th 14 of those 18 days were below norm. Many 10-15 degrees below. There was a 1-3 inch snow event and several other days of snow showery weather.

December 1989 saw a +2 spike. We know the frigid that unleashed.

Late Feb 1991 saw it hit +1.5 for for a few days around the 26th. Temps were -15 from norm in an otherwise very mild winter.

Peaked at almost +1.4 Jan 19th 1992. Had 5 days of -15 to -25 departures including one day near 0 in another very mild winter.

Spiked again in late Feb/Early March 1993. Winter had been an absolute dud until then. Snowed 2-4 inches late Feb, several snow showery days in early March, then the blizzard.

Hit +1.7 Feb 7th 1995 with several days above 1.5 that week. Snowed 3-6 in the area on the 7th, lows were below 0 on the 8th and 9th with highs in the teens on the 8th.

Big positive spikes basically fled in the late 1990s. Next was February 2000. It went above +1 on the 1st or so, getting to +1.6 on the 5th. Temps were generally around 10 degrees below normal and it snowed several days in a row.

Had a +1.5 peak just after New Years 2001 after being just above +1 in late Dec. Temps -15 to -20 from normal for most of that time frame with several days of snow showers in the mix, something like 9 of 15 days in my area. Lowest lows in the single digits multiple times, lowest highs in the lower 20s multiple times.

December 2001 saw it go to +1.3, peaking at +1.6 in early January. 2 weeks of snow showery weather and temps in the 15 degrees below normal range.

Steady positive through early to mid December 2002, peaking at +1.9 on the 13th before crashing back to neutral in the next few days. The first two weeks of the month were 6-15 degrees below normal on the various days.

Spike to +1.7 in February 2006 that translated into -15 from normal and a 3-6 inch snow event in the area.

December 8th 2006, +1.6. Highs in the upper 20s, lows in the single digits.

Early Jan 2010 got up to 1.4, highs in the 10s, lows in the single digits and snow during the time frame.

Even in dreadful 2012 we had a brief +pna at 1.5 that last for 4 days in mid Feb. Temps were -6, -18, -15 and -12 from normal at CSV those days.

Last February it spike to +1.4 around the 10th and we got the big V-Day storm.

This ended up being a long post that took a while. But the point is, we rarely see PNA spikes approach 2.0. When we do see them go above 1.4 there's a high high chance it will be followed by at the very least, cold weather. Often with precip either in NW flow or in the form a a big storm. The big spikes are far and away more likely to happen in February. But even in April we saw what a spike to 2.0 did in 1987. The above maps may not come to pass, but if they do...good good potential around that time frme regardless of exact threats a model may be showing for now.

 

 

 

 

 

 

 

 

Galloping Gaskets - I think I have been watching the baby channel too much - that is some great information thanks for all that hard work!

[Carvers Gap]

The time around the 10th has been showing up for some time as a favorable time.  I am usually not a Debbie Downer, but here goes...To be fair, shortly after that is still showing very warm temps on the ensembles.  The 6z GEFS takes a couple of extra days to get there.  The 0z GEPS and 0z EPS (quick glance) are warm overall after d10.  Basically the d10 PNA ridge rolls into the nation's midsection and gives the MJO 5-7 look, almost exactly.  All ensembles depict an expanding ridge w AN temps originating in the Plains shortly after d10.  As mentioned earlier the pattern could be trumped by -AO/+PNA combo.  But I am not seeing evidence that the PNA will hold in such a way to build a stable and lasting downstream trough w BN heights in the East. The model runs that do show some BN heights downstream often have help in the Atlantic.  The timeframe from Feb 10th to 25th looks very prone to warm temps.  Definitely hope I am wrong and that blocking can overcome a strong signal by the MJO for phases 5-7.  One last shot of cold water...the MJO looks to head into a high amplitude phase 8.  Saw a met on the MA forum say that is often followed by a crash into the COD.  Says it really needs to get to phase one for a stormy, winter pattern to develop.  I am going to have to see some big changes in the northern hemisphere pattern before jumping back on the cold band wagon.  Sustained cold has been muted or shortened in duration...every, single time this winter.  To quote packerbacker, right now find the warmest model and go with it...

[John1122]

Things seem to be slowly trending back to a potential snow event here next Fridayish. Euro and GFS now have a low, still very weak and ends up far south, but the NW trend is our friend as we know (until it's not) with these potential systems.

Day 10 looks pretty nice at 500 on the Euro as well.

[John1122]

Euro responds to the PNA spike late period and flips from way above normal temps here on 00z to below normal on 12z.  Maybe it won't work out, but as I posted above, it almost always does work. You essentially never see a majorly positive PNA without a cool down here, usually a significant one. Even in November or April. I wouldn't be surprised to see the Euro trend more in this direction as long as it keeps the big +PNA.

12z

 

00z

[Carvers Gap]

If we are going to capitalize on short window the PNA ridge is strongest...we either need a blocking scenario or we need a combo scenario.  First one is prob not happening.  Second one is possible.  What we need is a "thread the needle" situation where the first storm amplifies the downstream trough and forces the trailing system under the base of that trough.  Then we need the timing to be such that there is enough separation to allow the second system to be forced into the perfect slot.  To me it is similar to a screen in basketball.  While the GFS and Euro have been truly awful past d6-7, they do hint at a window where this second scenario is possible.   There is really no long term cold showing on the ensembles or operationals, and that is usually our best recipe for winter...where cold is in front of the incoming system like we had in early January.  For this potential window, we need the first storm to do the dirty work, because there is no blocking in the Atlantic that will slow the cold(always in and out) or slow the flow.  The first system will have to do both.  Overall, still not very enthused w the LR past d10....until late month.  But if we steal a snow during the warm-up and then later this month...that is about the best we could have hoped for.    We really have scored on the only system shown this winter.  We are one for one north of 40.  (I do realize Chatt is shutout...edit)Feb and early March are well known to be great climo for here.  Sometimes climo trumps everything else.

[jaxjagman]

Pattern upcoming towards the last week into Feb into March could be cold and dry.Nothing is showing up in East Asia on the GEFS long range.Hovmollers look dry also,maybe the only hope is clippers?

 

 

 

 

[jaxjagman]

8 hours ago, John1122 said:

Euro responds to the PNA spike late period and flips from way above normal temps here on 00z to below normal on 12z.  Maybe it won't work out, but as I posted above, it almost always does work. You essentially never see a majorly positive PNA without a cool down here, usually a significant one. Even in November or April. I wouldn't be surprised to see the Euro trend more in this direction as long as it keeps the big +PNA.

12z

 

00z

Probably not going to work out for winter as the models are hinting at a more long wave,probably just a linear line with winds right now by the looks

[jaxjagman]

16 minutes ago, jaxjagman said:

Probably not going to work out for winter as the models are hinting at a more long wave,probably just a linear line with winds right now by the looks

The dashboard also shows a severe risk into the S/C/Plains lower MS/Valley,Ozarks,OV maybe

 

[BlunderStorm]

Surprise late night Snowfall tonight for SWVA and maybe the Tri-Cities. Maybe a dusting is possible. I wouldn't be surprised if the mountains such as (High Knob, Beartown, Big A, Rogers, Pine, Brumley, Whitetop, Holston, White Rock, Clinch, ETC...you get the idea.) collected a little more in a sudden burst. That or virga has made a fool out of me again. *update* A trail mix of precipitation is falling a tad too warm for snow still fun to look at. That being said I need some sleep.*update 2* a trace of snow is on the ground. Bringing the seasonal accumulated total up to 7.25 inches.

[Carvers Gap]

I have been doing some digging into how long it takes for particular MJO signals to propogate to the US.  Right now, the best I can find is one to two weeks.  While looking, I ran across this paper about the MJO.  Decent read.

http://www.albany.edu/honorscollege/files/findlay_thesis.docx

[jaxjagman]

GFS  has a split,GEFS  tries but not enough ummph

 

 

 

 

 

[Carvers Gap]

Euro weeklies continue to advertise a Marvelous Early March.  It is true that they actually show that, and it is true that I am saying this with more than a touch of sarcasm.   But looks like one last window just at the end of Feb and for early March.  You know it is a bad winter for snow and temps when we are mailing in weeks at a time during primetime.  Might be a couple of outside chances before that(me sayihg that and not the weeklies).  The Weeklies did look like a reasonable progression and not wonky. At this point in the season, would like one or two more events to track.  Climo is tougher with each passing day and more so by late month.  But this is the time of year for big swings(of the bat).  I am realistic that the pattern is bad.  I am trying not to bang that drum too hard, but there are entire weeks of torchiness.  That said, I do like the very end of winter for one mo shot.

[Carvers Gap]

Some major difference between the GEM/Euro vs GFS between days 8-10....and even after that.   

[Carvers Gap]

Pretty decent -NAO showing up after d10 FWIW on the ensembles.  If it is real and can couple w John's PNA there may be a brief window around Feb15.  Bit of a long shot since the window is small...but it is becoming a consistent feature on both ensembles.  Now, be forewarned, many of those looks have not verified once inside d10, especially the -NAO.  We have needed help from the Atlantic this winter.  So, anytime I see temporary blocking in the Atlantic...time to perk-up.  Slows the flow and holds the cold.   Not overly fired-up at this point as cold and energy have been out of sync all winter.  But that look is far less boring than what we have now.

[rbowman]

I honestly can't remember the last winter that we have received much help from the Atlantic. Seems like the NAO tanks in the summer and then wants to stay positive most of the winter. Maybe when we get sn AMO flip - who knows?

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[Carvers Gap]

35 minutes ago, rbowman said:

I honestly can't remember the last winter that we have received much help from the Atlantic. Seems like the NAO tanks in the summer and then wants to stay positive most of the winter. Maybe when we get sn AMO flip - who knows?

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Agree on all counts....long term help has been seldom.  But when it shows on models it is usually a pretty good signal if it actually is real.  I do have my doubts that the look verifies(placement and strength) on the morning GEFS runs.  That model has been notorious for showing that look only to back off.   I have adopted a healthy dose of skepticism of late.   However, there are some signs that high latitude blocking may show...MJO and of course now that winter is almost over.  The one modeled around the 15th has been portrayed as transient...talking less than 96 hours.  The non-American models are basically a no go.  But watching because there is nothing else to watch before the late month potential window.

On on a different note....the northern stream system is looking pretty decent for the NE on the 12z GFS.  Just shows how late season energy has to be watched.  Mtns might get a quick shot of light accums from that.

[Angry Smokey]

6 hours ago, Carvers Gap said:

Agree on all counts....long term help has been seldom.  But when it shows on models it is usually a pretty good signal if it actually is real.  I do have my doubts that the look verifies(placement and strength) on the morning GEFS runs.  That model has been notorious for showing that look only to back off.   I have adopted a healthy dose of skepticism of late.   However, there are some signs that high latitude blocking may show...MJO and of course now that winter is almost over.  The one modeled around the 15th has been portrayed as transient...talking less than 96 hours.  The non-American models are basically a no go.  But watching because there is nothing else to watch before the late month potential window.

On on a different note....the northern stream system is looking pretty decent for the NE on the 12z GFS.  Just shows how late season energy has to be watched.  Mtns might get a quick shot of light accums from that.

Newb here, Where is best place to look for this northern stream? Basically, do we need to see the moisture build in eastern Montana/Canada similar to last week? TIA, trying to learn here

[Carvers Gap]

21 minutes ago, Angry Smokey said:

Newb here, Where is best place to look for this northern stream? Basically, do we need to see the moisture build in eastern Montana/Canada similar to last week? TIA, trying to learn here

No problem.  On the link below(might be time sensitive) you can see the low in the northern stream and one in the southern stream.  Sometimes, energy comes from just one stream.  If those two pieces were to form one storm, that is a phase.  The system over DC during the next day or so is northern stream only system.  The one below shows both.  I think technically there are three streams...but it is rare to see all three interact.  It is much easier to see the two streams if you loop the model.

[rbowman]

Good description above. The 2 streams that usually influence our weather are the polar jet stream (northern) and the subtropical jet stream (southern).

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[Angry Smokey]

41 minutes ago, Carvers Gap said:

No problem.  On the link below(might be time sensitive) you can see the low in the northern stream and one in the southern stream.  Sometimes, energy comes from just one stream.  If those two pieces were to form one storm, that is a phase.  The system over DC during the next day or so is northern stream only system.  The one below shows both.  I think technically there are three streams...but it is rare to see all three interact.  It is much easier to see the two streams if you loop the model.

Thanks! Hoping for one more decent snow chance before we move on to next winter

[Carvers Gap]

Where the two streams come together is the area of confluence.  Looking for areas of confluence on LR model can help us spot big storms, but not always.  Some big storms are not phases.  For E TN...We generally want to see the confluence area just to our east in central or southern GA...or the coastal plain of SC or NC if the system is moving slowly.  Ideally, we want the system phased just to our south or southeast. Too late and out to sea...too early and it cuts west of the Apps.    In NE TN we can handle a later phase if the storm is strong.  Now, our middle and west forum folks prob want confluence over Alabama or MS.  Then, the storm cuts up the eastern TN valley.   Lastly, the reason we all like the -NAO is because it slows/blocks both streams.  It is like the kid in the front of the line stopping suddeny.  Everybody just piles up behind.  With blocking areas of confluence show up where the blocking forces both streams northward. They just back-up storms in each stream and make a phase more likely as storms slow.

[Angry Smokey]

2 minutes ago, Carvers Gap said:

Where the two streams come together is the area of confluence.  Looking for areas of confluence on LR model can help us spot big storms, but not always.  Some big storms are not phases.  For E TN...We generally want to see the confluence area just to our east in central or southern GA...or the coastal plain of SC or NC if the system is moving slowly.  Ideally, we want the system phased just to our south or southeast. Too late and out to sea...too early and it cuts west of the Apps.    In NE TN we can handle a later phase if the storm is strong.  Now, our middle and west forum folks prob want confluence over Alabama or MS.  Then, the storm cuts up the eastern TN valley.   Lastly, the reason we all like the -NAO is because it slows/blocks both streams.  It is like the kid in the front of the line stopping suddeny.  Everybody just piles up behind.  With blocking areas of confluence show up where the blocking forces both streams northward. They just back-up storms in each stream and make a phase more likely as storms slow.

Good stuff, so best place for models is what you linked above?