Winter 2015-16

[tnweathernut]

Relax and get your rest the next week to 10 days.  It's likely we aren't done with winter in the TN Valley.  Tall PNA's and large highs might be in our future after the cutter next mid week.  Shortly after that we may have opportunities.

[jaxjagman]

 

DAY 4-8 CONVECTIVE OUTLOOK CORR 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0406 AM CST WED JAN 27 2016

   VALID 301200Z - 041200Z

   CORRECTED FOR WORDING IN SECOND PARAGRAPH

   ...DISCUSSION...
   THE MEDIUM-RANGE MODELS CONTINUE TO INDICATE THAT A STRONG
   MID-LATITUDE SHORT WAVE TROUGH WILL DIG INLAND ACROSS THE CALIFORNIA
   COAST LATE THIS COMING WEEKEND...AND RAPIDLY THROUGH THE FOUR
   CORNERS REGION BY EARLY MONDAY.  DIFFERENCES BETWEEN THE ECENS AND
   NCEP MREF THEN SLOWLY BEGIN TO INCREASE CONCERNING THE SPEED OF
   FORWARD PROGRESS...EASTWARD ACROSS THE CENTRAL/SOUTHERN
   ROCKIES...AND NORTHEASTWARD THROUGH THE MISSISSIPPI VALLEY BY THE
   MIDDLE OF NEXT WEEK.  HOWEVER...AGREEMENT EXISTS CONCERNING SUPPORT
   FOR STRONG SURFACE CYCLOGENESIS FROM THE SOUTH CENTRAL PLAINS
   THROUGH THE LOWER OHIO VALLEY.  AND IT APPEARS PROBABLE THAT A
   SUBSTANTIVE RETURN FLOW OF MOISTURE FROM THE GULF OF MEXICO INTO THE
   WARM SECTOR OF THE LOW WILL EVENTUALLY SUPPORT A CONSIDERABLE
   INCREASE IN POTENTIAL FOR SEVERE STORM DEVELOPMENT...IN THE PRESENCE
   OF STRONG VERTICAL SHEAR.

   GUIDANCE IS SUGGESTIVE THAT A 100 KT WESTERLY JET STREAK AT 500 MB
   WILL ACCOMPANY THE UPPER SYSTEM...WITH A 50-70 KT SOUTHERLY JET AT
   850 MB DEVELOPING BY NEXT TUESDAY ACROSS THE LOWER MISSISSIPPI
   VALLEY.  DIFFERENTIAL THERMAL ADVECTION AND STRONG FORCING FOR
   UPWARD VERTICAL MOTION MAY SUPPORT INCREASING POTENTIAL FOR SEVERE
   STORMS ACROSS PARTS OF THE SOUTH CENTRAL PLAINS INTO THE ARKLATEX
   AND OZARK PLATEAU AS EARLY AS MONDAY NIGHT.  HOWEVER...CONFIDENCE IN
   SUBSTANTIVE LOW-LEVEL MOISTURE RETURN /SURFACE DEW POINTS INCREASING
   THROUGH THE 60S...PRECIPITABLE WATER INCREASING UP TO 1.25 INCHES/
   AND BOUNDARY LAYER DESTABILIZATION IS GREATER ON TUESDAY ACROSS THE
   LOWER MISSISSIPPI VALLEY.  SEVERE STORM DEVELOPMENT AS FAR NORTH AS
   THE MIDDLE MISSISSIPPI AND LOWER OHIO VALLEYS DOES NOT APPEAR OUT OF
   THE QUESTION BY TUESDAY...AND EASTWARD TOWARD THE APPALACHIANS AND
   SOUTHEAST NEXT WEDNESDAY...BUT LOWER CONFIDENCE PRECLUDES 15 PERCENT
   SEVERE PROBABILITIES ACROSS THESE AREAS AT THIS TIME.

   ..KERR.. 01/27/2016

[tnweathernut]

Just for fun, but on the 12z Euro it looks like we build a -NAO starting at hour 168 that continues through the end of the run. It's not a monster block, but it certainly better than raging positive too.  It's orientation isn't great, but I'd call it helpful.  At the same time it appears there are a couple of pieces of the PV floating around in eastern Canada under this blocking.  

You also have a -AO building from hour 96 eventually reaching a closed block by 144.  There should be cold high pressures building in Canada and sliding southeast into the upper midwest before spreading out beyond this time period.

Between hours 192 and 240, you have a healthy southern vort moving from central California through AZ and NM into the Texas panhandle.  At the same time you have a vort diving southeast from Montana which looks like it could try and phase with the southern system past 240.  Looking upstream this system would have a hard time cutting though it could head ENE.

 

I am guessing this at least has the potential to be a time period to watch just after our warmup and cutter for next early and midweek.  Way too much in the way of specifics here, but I found it interesting anyway and wanted to share, especially after having withdrawals from several days with nothing wintry to track...  

[Daniel Boone]

Lost most of our snow yesterday as an all day moderate Rain took it's toll even though the high was only 39. 0.69" fell, well above guidance. Lee county received the heaviest amounts in the e. Tenn./ Swva area. Much more than most. Therefore, those areas kept much of their snow.

[weathertree4u]

Just for fun, but on the 12z Euro it looks like we build a -NAO starting at hour 168 that continues through the end of the run. It's not a monster block, but it certainly better than raging positive too.  It's orientation isn't great, but I'd call it helpful.  At the same time it appears there are a couple of pieces of the PV floating around in eastern Canada under this blocking.  

You also have a -AO building from hour 96 eventually reaching a closed block by 144.  There should be cold high pressures building in Canada and sliding southeast into the upper midwest before spreading out beyond this time period.

Between hours 192 and 240, you have a healthy southern vort moving from central California through AZ and NM into the Texas panhandle.  At the same time you have a vort diving southeast from Montana which looks like it could try and phase with the southern system past 240.  Looking upstream this system would have a hard time cutting though it could head ENE.

 

I am guessing this at least has the potential to be a time period to watch just after our warmup and cutter for next early and midweek.  Way too much in the way of specifics here, but I found it interesting anyway and wanted to share, especially after having withdrawals from several days with nothing wintry to track...  

I have to say I like where the pattern is headed and feel like we have at least one more good snow in our future. I sincerely hope we can get away without any ice. Seen arctic fronts get hung up over the TN Valley too many times.

[Runman292]

Here's David Aldrich's confidence cast for temperatures this weekend and next weekend.

[stadiumwave]

Relax and get your rest the next week to 10 days.  It's likely we aren't done with winter in the TN Valley.  Tall PNA's and large highs might be in our future after the cutter next mid week.  Shortly after that we may have opportunities.

FEB 8-14TH....couple of chances

[Greyhound]

FEB 8-14TH....couple of chances

Nice to see somebody from my hometown posting!!!

[jaxjagman]

Into the 2nd wk of Feb is looking interesting looking at the GEFS  .DT already made a post of the about this time frame on the main board

 

http://www.americanwx.com/bb/index.php/topic/47758-rut-roh-raggy/

[nrgjeff]

I favor the guarded stance from Don. http://www.americanwx.com/bb/index.php/topic/47332-winter-2015-2016-medium-term-discussion/?p=3932543

 

Sure sounds more reasonable than forecasting a winter storm Day 10. Today and tomorrow generated chatter 7 days ago. Better to count our blessing from last week.

 

Next 2-3 weeks feature less than impressive winter weather except a passing but sharp cold front late next week. Frankly, I'm a lot more interested in the thunderstorms ahead of the front. No surprise? 

 

Otherwise blocking attempts appear half-way and PNA ridging gets undercut by Pacific flow. MJO is either dead or in warm zones. Dead MJO or weak cold zones favors strong El Nino forcing mild.

 

March or even late February may offer another opportunity for cold. I am not looking for any SSW but perhaps the tropospheric vortex will get jostled again. MJO is forecast to maybe drift into colder phases in a few weeks.

[Coach B]

 

 

Next 2-3 weeks feature less than impressive winter weather except a passing but sharp cold front late next week. Frankly, I'm a lot more interested in the thunderstorms ahead of the front. No surprise? 

 

Otherwise blocking attempts appear half-way and PNA ridging gets undercut by Pacific flow. MJO is either dead or in warm zones. Dead MJO or weak cold zones favors strong El Nino forcing mild.

 

March or even late February may offer another opportunity for cold. I am not looking for any SSW but perhaps the tropospheric vortex will get jostled again. MJO is forecast to maybe drift into colder phases in a few weeks.

Looking at the long range ensembles the last couple of days I was starting to get cautiously optimistic about February. Talk about a bucket of cold water!  Of course you are right, tapping the brakes/tempering the expectations is never a bad idea when it comes to wintry weather in the South. Thanks Jeff!

[Runman292]

I'm looking forward to a snowy February.

[John1122]

I think there's a very good chance we get back into the freezer for February, though I was skeptical of it earlier this month. 

 

January was much colder than any of the long range models predicted. CFSV2 on Dec 31st had above normal from I40 north and wayyyyy above normal from 1-80 north for January. This is what actually happened.

 

 

 

 

[John1122]

Tomorrow will be cold again and many of us will see snow showers/flurries overnight into Friday. Then we get basically Saturday-Tuesday above normal. After that we start seeing decent departures below normal.

 

 

 

 

Of course this is all subject to change, but it's been pretty consistently modeled. Joe Bastardi has been pointing out the current strat warming event and it shows that if one occurs in Early Feb during the last few Ninos, temps get well below normal from the Dakotas to Texas and points East. As to any snow, as always, it's all about timing. We could be below normal every day except the days the precip arrives or even be below normal those days and still rain. But I like having cold around and taking my chances.

[jaxjagman]

Tomorrow will be cold again and many of us will see snow showers/flurries overnight into Friday. Then we get basically Saturday-Tuesday above normal. After that we start seeing decent departures below normal.

 

 

 

 

Of course this is all subject to change, but it's been pretty consistently modeled. Joe Bastardi has been pointing out the current strat warming event and it shows that if one occurs in Early Feb during the last few Ninos, temps get well below normal from the Dakotas to Texas and points East. As to any snow, as always, it's all about timing. We could be below normal every day except the days the precip arrives or even be below normal those days and still rain. But I like having cold around and taking my chances.

And this should add up to what the EPS in east Asia  is showing but a couple days after this.Think the weeklies will back off the cold it's been showing to around the 12th-13th to the 16-17,but this will be more transit.If the MJO is right like Jeff mentioned above the MJO is being shown in the cold phase towards wk3 to 4 of Feb,if its right of course but we are headed into a transition period during this time into spring,with the enso still hanging on,is this more severe than cold?

[Carvers Gap]

Just for fun, but on the 12z Euro it looks like we build a -NAO starting at hour 168 that continues through the end of the run. It's not a monster block, but it certainly better than raging positive too.  It's orientation isn't great, but I'd call it helpful.  At the same time it appears there are a couple of pieces of the PV floating around in eastern Canada under this blocking.  

You also have a -AO building from hour 96 eventually reaching a closed block by 144.  There should be cold high pressures building in Canada and sliding southeast into the upper midwest before spreading out beyond this time period.

Between hours 192 and 240, you have a healthy southern vort moving from central California through AZ and NM into the Texas panhandle.  At the same time you have a vort diving southeast from Montana which looks like it could try and phase with the southern system past 240.  Looking upstream this system would have a hard time cutting though it could head ENE.

 

I am guessing this at least has the potential to be a time period to watch just after our warmup and cutter for next early and midweek.  Way too much in the way of specifics here, but I found it interesting anyway and wanted to share, especially after having withdrawals from several days with nothing wintry to track...  

 

 

Tomorrow will be cold again and many of us will see snow showers/flurries overnight into Friday. Then we get basically Saturday-Tuesday above normal. After that we start seeing decent departures below normal.

 

Of course this is all subject to change, but it's been pretty consistently modeled. Joe Bastardi has been pointing out the current strat warming event and it shows that if one occurs in Early Feb during the last few Ninos, temps get well below normal from the Dakotas to Texas and points East. As to any snow, as always, it's all about timing. We could be below normal every day except the days the precip arrives or even be below normal those days and still rain. But I like having cold around and taking my chances.

 

12z EPS (control and mean) and 12z GEFS show considerable cold dropping into the country's mid-section after Feb 5th and lasting through at least the 12th.  Both have been showing that for a bit.  The 12z Euro OP did not agree w/ its ensembles today as it(op)  was a good deal warmer.  I don't like seeing the CPC ensembles out of sync today - their signal is warm.  They signaled the flip at the end of February quite nicely.  The current PNA is positive which fits the LR models.  The AO is all over the place which may signal a drop in the future.  As Jeff, pointed out DonS was pretty guarded about February, and I hesitate to go against him or the CPC teleconnections.  He is like money in the bank w/ his forecasts.   The MJO is also not in sync for winter weather.  So, I tread on the thinnest of later winter's ice when saying it certainly looks like the return of winter on February 5th-ish.  The LR models (ops/ensembles) have been consistent in this cold depiction for well over a week, rarely even skipping a beat.   So, at some point...either the model or the indices are going to have to give.  Bad teleconnections, the MJO being out of phase, and DonS...give me very low confidence in saying it will return to winter sooner than later.  But model consistency among several models(ops/ensembles) gives me the lean towards the cooler direction.  Plus, climatology favors snow in the TN Valley for February.  But I cannot lie, very close call on that decision. 

 

As for storms, the MA blizzard was modeled about eight days out by the GFS and Euro.  They rarely wavered.  This weekend is a miss for sure(and was noted correctly by most here three days ago) , and for me anyway, falls in the category of the "false second storm signal" that seems to follow many blizzards on modeling.  

 

With cold air coming and an active southern branch, tough not to see more wintry wx not showing up in February.

[John1122]

This is what the Cansips advertised for Jan on December 1st.

 

 

This is what it advertised for February on Jan 1st.

 

 

It's pretty much taking the CFS to school.

[John1122]

Last two Nino Febs with strat warming event. Which is underway per Joe B. with various models showing quite a disruption in the PV in a week or so, especially the UKmet.

 

 

 

 

[John1122]

The PNA is on our side, hopefully it's joined by the AO, although last February was as wintery as any time in my life and it had a positive AO and NAO. Last year we had massive winter storms and -10 to -15 degree cold with the AO between +2.5 and +4. The pacific drove the pattern that much.

[Carvers Gap]

The PNA is on our side, hopefully it's joined by the AO, although last February was as wintery as any time in my life and it had a positive AO and NAO. Last year we had massive winter storms and -10 to -15 degree cold with the AO between +2.5 and +4. The pacific drove the pattern that much.

The most recent run of the CFS2 (1.27) is now bringing some weak cold anomalies to the GC states and is overall a weakening version of its original warm self. Has a strange habit of "correcting" during the last few days preceding its upcoming forecast month.

[Daniel Boone]

12z EPS (control and mean) and 12z GEFS show considerable cold dropping into the country's mid-section after Feb 5th and lasting through at least the 12th.  Both have been showing that for a bit.  The 12z Euro OP did not agree w/ its ensembles today as it(op)  was a good deal warmer.  I don't like seeing the CPC ensembles out of sync today - their signal is warm.  They signaled the flip at the end of February quite nicely.  The current PNA is positive which fits the LR models.  The AO is all over the place which may signal a drop in the future.  As Jeff, pointed out DonS was pretty guarded about February, and I hesitate to go against him or the CPC teleconnections.  He is like money in the bank w/ his forecasts.   The MJO is also not in sync for winter weather.  So, I tread on the thinnest of later winter's ice when saying it certainly looks like the return of winter on February 5th-ish.  The LR models (ops/ensembles) have been consistent in this cold depiction for well over a week, rarely even skipping a beat.   So, at some point...either the model or the indices are going to have to give.  Bad teleconnections, the MJO being out of phase, and DonS...give me very low confidence in saying it will return to winter sooner than later.  But model consistency among several models(ops/ensembles) gives me the lean towards the cooler direction.  Plus, climatology favors snow in the TN Valley for February.  But I cannot lie, very close call on that decision. 

 

As for storms, the MA blizzard was modeled about eight days out by the GFS and Euro.  They rarely wavered.  This weekend is a miss for sure(and was noted correctly by most here three days ago) , and for me anyway, falls in the category of the "false second storm signal" that seems to follow many blizzards on modeling.  

 

With cold air coming and an active southern branch, tough not to see more wintry wx not showing up in February.

Could be a similar pattern to the one back in late Dec./early Jan. that brought big snows to the southern plains.Mjo was in warmer phases for East the. Also, the normal outcome for Mjo phases are somewhat off kilter during ninos.especially, strong ones.. Doubt there would be the exact same outcome here as AO was still quite positive then. So, more of that cold will prob. Bleed East even so.

[jaxjagman]

The MJO on the euro is getting some stronger signals away from the COD in P4,it surely today reflects to what the weeklies are showing.I don't have my 5 and 85 maps loaded yet but by looking at the 2m's it looks flat out ugly now heading into wk3 and 4.We need help by the looks from a displaced PV.

[Daniel Boone]

Yeah, think definitely gonna need that to happen and preferably initiate a decent -nao, as even what cold that did make eastward intrusions could most likely be behind systems, thus cold chasing moisture. Last Feb. Was unusual in that this area was slammed repeatedly even with a +AO and nao but, the +pna was out the roof and one lp after another at rather close distance followed one another up through Eastern Canada into Greenland and therefore disrupted the normal +nao action.

Instead of funneling the cold around the lp over Greenland into the north atlantic, as is the case with a typical +nao, the lined up lp's funnelled that cold southward into the Midwest/Ohio and Tenn. Valley.

[Carvers Gap]

The MJO on the euro is getting some stronger signals away from the COD in P4,it surely today reflects to what the weeklies are showing.I don't have my 5 and 85 maps loaded yet but by looking at the 2m's it looks flat out ugly now heading into wk3 and 4.We need help by the looks from a displaced PV.

Just looked briefly at the NA pattern on the weeklies and on the 46 day parallel...did not feel the weeklies or parallel looked that bad for 850 anomalies or at 500. What am I missing, everybody? Again, close call to go w cooler than normal for sure. Seeing mainly a lot of back and forth which would be to our benefit IMO.

[John1122]

Reading about some Euro monthly forecast verification scores. The skill of the model drops by 75-90 percent beyond day 14 according to research I'm reading about. It says that beyond week 2 it's only useful over oceans for things like Nino forecasts.

[Carvers Gap]

Yeah, think definitely gonna need that to happen and preferably initiate a decent -nao, as even what cold that did make eastward intrusions could most likely be behind systems, thus cold chasing moisture. Last Feb. Was unusual in that this area was slammed repeatedly even with a +AO and nao but, the +pna was out the roof and one lp after another at rather close distance followed one another up through Eastern Canada into Greenland and therefore disrupted the normal +nao action.

Instead of funneling the cold around the lp over Greenland into the north atlantic, as is the case with a typical +nao, the lined up lp's funnelled that cold southward into the Midwest/Ohio and Tenn. Valley.

The one advantage is that the northern jet on average (per wxsouth) is at its southernmost latitude in Feb. WxSouth had a great article this evening. Basically said that the cold air has not made as far south as modelled this winter. Said the battle zone should set-up just north of I40. Going to be interesting as climo/models are opposite the MJO/teleconnections.

[Carvers Gap]

Reading about some Euro monthly forecast verification scores. The skill of the model drops by 75-90 percent beyond day 14 according to research I'm reading about. It says that beyond week 2 it's only useful over oceans for things like Nino forecasts.

IMO, it has been blind to cold for two big cold outbreaks during the last two winters. Again, I didn't think they looked all that bad tonight. Lots of seasonal back and forth like would be expected in Feb.

[Daniel Boone]

Where's the article Carver ,Is it on his member site ?

[John1122]

This is directly from the report on the 30+ day European model forecasts.

"In forecast week 2 (days 12-18), continental skill drops to much lower values of about 0.1-0.2. Beyond forecast week 2, pronounced prediction skill is predominantly found over the oceans, particularly over the ENSO region and in the central and eastern Pacific. Continental skill, however, essentially vanishes after forecast week 2, apart from some areas in tropical Africa and South America. "

[Carvers Gap]

Where's the article Carver ,Is it on his member site ?

Pay site. Had an article about the next six weeks. Was very well written.