Sunday, January 13, 2019

Winter wakes up

1-24  Results


We had 2-4" generally in the I84 corridor with 4-5" to the north.  DXR reported .35" of ice. Meriden Airport  reported .57" of ice.  I'd go with .45" for here. Other reports from Upton are here

Started as snow Sat evening, transitioned briefly to sleet, so that we didn't even hear it.  Then around 3am we lost power.  Came back around 4:30.  Then went off again around daybreak.  Generator went on around 8am.  Power came back around 11:30am and went off from 2:30pm Sunday until 5pm Monday.

Temps plummeted to -1 Monday morning and the generator ran longer hours than usual. Winds gusted to 40mph.  Newtown had 25% of customers without power at the peak.

The low pressure actually passed just south of LI, which was only forecast by a few models, NAM3k, WRFARW2 and ICON.  NAM 3k came closest to idea of ice. 

1-19 - Well its here.  NAM abandoned the idea of a southern low, now all models agree.
NWS was a little slow recognizing this but has since lessesed the expected amounts.  These snow amounts are only possible if we get a good front thump of snow sometime between 10pm and 2am (adjust to 8pm and midnight for NJ, etc).  I'm uncomfortable giving up on the idea of ice in the I84 corridor and north.  But snow looks right. Its not all that cold out at 6:30 pm.  32°



1-18  late afternoon

Despite many attempts to draw a snow map, I've given up.  The system coming across the country now has little opportunity to shift. The questions are does it head through the Cumberland gap and out the Delmarva/ACY area, ala the NAM, or does it go through PA/NJ over NYC and inside ACK?

Whichever, we will get some heavy snow to start.  Typically these events stay snow longer than forecast, and the ground temp stays cold longer. Moisture streams in faster than the rise in temps.   Then the NAM has us in CT going to sleet.  GFS/Euro/CMC/UKMet have us turning to rain.

Winter Storm warnings have gone up for most of the area. The NWS office in Upton has the following outlooks

 I think it may be overdone, but only by an inch.  I like this map too.

 Euro is my second favorite, GFS third
12z Euro

12z GFS
Freezing rain remains a threat.  Pay attention to this line as it can cause some serious trouble.  NWS says its more likely sleet than freezing rain though.


1-16 evening

We did see shifts today in the 12z runs and the NAM is starting to come into range and looks to be colder than the GFS.  Actually, the hr 84 of the nam had the temp here at 19 while the GFS was 35.  😲
I can't figure out why the GFS isn't shifting further SE, which is concerning me.   The pieces of the storm are the main storm(A). Energy from the north (B) and energy from the west (C).


Parts B&C act to steer the storm.  Should they remain separate from A, as depicted on the NAM run below, then the storm should exit south of the area and bring more in the way of frozen precip.


If either part ends up in the back side of the trough, that may cause the trough to tilt negative and the storm comes up to our west or over us. GFS was advertising this yesterday, but no longer does.  The problem is that it didn't correct enough.

WXDisco comment on this


1-16  Tomorrow is the day to really start taking model runs seriously.  Yesterday morning started out with a shift NW of the GFS, Euro, Navy and GEM.  Then in the afternoon, the UKMET, usually the furthest west, jumped to an off shore solution.  Slowly the GFS and Euro have followed with the shift evident in the images below.   The energy for this storm is hitting the coast on the 17th.  Currently there is no data other than from satellite so models have less to go on.  This is why through the day Thursday and into Friday, there could be some major changes.

Wednesday morning Euro snowfall forecast

Tuesday afternoon Euro snowfall forecast

0z Wednesday Euro ensemble members

12z Tuesday Euro ens members
The GFS snowfall GIF shows the retreat NW yesterday then a jump to the coast today.


The Experimental GFS Replacement FV3 also shows the advancing southeast of the snow line


GEM shifted SE too
Timing and track are not the only open questions.  We have to contend with two different scenarios with type of storm as well.  GFS is more strung out like a frontal passage.  Two lows develop and as the trough approaches, they ride up in front of it.  The other low is by the yellow convection
While the GEM, Euro, JMA, UKMET all have a single low.
CMC single low as example

The timing portion is do they ride up before, after or during the cold front passage. The track depends where the trough is - the track is pretty certain to be between midway to the 40/70 benchmark and Albany.  Closer the benchmark means all snow, Albany means snow to rain.  In between may result in snow-ice-rain-ice-snow.  We're only talking 200 miles difference here 4 days out.


1-13  Winter woke up today in the Mid Atlantic with 2-6" of snow reported in the VA/DC/MD area.  But as alluded to in the last post, a more meaningful storm is brewing for MLK weekend.

This will grab attention!
0z Canadian

6z FV3

18z FV3

18z GFS
Well you laugh and say, thats the GFS or FV3 - what about the Euro
We're a week out or so.  Don't be surprised to see this move out of our area the next two days.  But if that happens, check back in on day 3 or 4.   

Details as to what causes this storm when I have time to look at it more, along with a what can go wrong analysis.  Sadly with work and a wake tomorrow, Tuesday might be the earliest I can spend some time.

Thursday, January 10, 2019

ZZZZZZ......old man winter sleeping

1/10  Well this post shouldn't take long.  Next chance at meaningful snow is around the 20th.  Being 10 days out, I'm not biting.  The snow this weekend should stay south, more impactful around DC/Delmarva.

Out of boredom, some stats from my area.

Counting today's snow showers, we've now had 6 days in which it snowed in December and January, surpassing the # of days it snowed in November finally.

Using OXC (Oxford/Waterbury Airport) as my official weather info climate site I've found the following interesting.

  • we haven't had a low temperature that was below normal since December 19th.  
  • since December 1st, we've had 8 nights with below normal low temps, all before December 19th and were mostly in the 12/4 to 12/12 date range
  • December was 2.9° above normal with 7.24" of rain and 0.5" of snow.  Normal precip is 3.65"
  • November was also wet with 7.28" of rain.  Normal is 4.26".  Also had 8" of snow
  • Since December 14th, there have been 3 days averaging below normal temps, and those were -2
  • January is running +8.5 temperature wise and on par for precip
  • Our average temperature (high+low)/2 is 34.2 which is higher than our average high.
  • OXC coldest days are 1/14 to 1/27 where highs are 33 and lows are 13.
There's been a lot of chatter about a sudden stratospheric warming (SSW) that took place in the beginning of the month.  These typically shake up the troposphere eventually and are thought to bring colder temperatures.  There is a shot at that on the Euro weeklies, but it doesn't stick around.  Not what is usually expected from an SSW event.



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Looking at December stats from DXR.  High temp of 62, low of 13.  Average departure 1.8 (likely +2 after today).  Precip was 124% of normal. 0.6" of snow.

Looking at other Decembers with under an inch of snow: 2011, 2014 and 2015.  Throwing out 2015 since it was 12 degrees above normal and dry.

Dec 2011 - High temp of 60, low of 13 (very similar).  Average departure +4.8 (a little warmer, but yet a torch).  Precip 126% (very close) and snow a trace.
Dec 2014 - High temp 61, low 13 (very similar).  Average departure +2.8 (closer than 2011).  Precip 110% (pretty close) and snow .4"
So what happened in Jan-Mar of 2012?  Stayed warm the entire winter.  January +4.8; Feb +4.1 and Mar +8.  11" of snow between those three months.  
And Jan-Mar of 2015?  Brutally cold - seriously bad.   January 3.6 degrees below normal with 16" of snow; Feb was nearly 16 degrees below normal with 26" of snow and Mar was 7.6 below normal with 14" of snow. 
Even after the torch of Dec 15, we came back with 26" of snow in Jan-Mar. 

Point is that, well, anything can happen.

Thursday, December 13, 2018

White, wet or green Christmas


12-23
Every model showing snow now. Dusting to 2".  Euro and ICON have the least amounts.
GFS

Canadian Global
Canadian Regional
Canadian Hi Res
NAM
NAM hi Res

German ICON

Euro


12-22  Still a good chance for light snow.  Actually, it should snow, just not sure if its flurries, snow showers or more sustained.  Depends how much moisture makes it over the Appalachians.  Nothing to be worked up over, just mood flakes.  The 2" areas are in blue. 
NAM

Euro

GFS


12-20  There's a shortwave disturbance that is out there on the Euro for the 12-24 to 12-26 period.  Brings a dusting to an inch .



 FV3 has it too


12-15  And just like that, the snow opportunities disappear.  That storm on the 21st really goes bonkers on the GFS and brings  2+" of rain.
There is a following clipper that drops down behind it, but its very light. Could provide mood snow for Christmas Day, but nothing worse at this point.
FV3 has the 12-21 storm further east and weaker, but the clipper behind completely falls apart.
Euro lacks the clipper altogether.

6z navgem has an interesting solution - keep the southern and northern stream separate, and run the storm in the gulf up the seaboard like a miller a type storm.  Weaker storm, but keeps the warm air from coming up.  But there isn't a lot of cold air to work with either.
So this mornings update is a green Christmas, possible with mood flakes.





12-13
With Christmas coming into long range on the GFS, FV3 and EPS, will there be snow on the ground, in the air, rain or just green?

Today's FV3 did not disappoint with multiple chances at moderate snow.




EPS from 0z today also looks good with a good size storm on Christmas day
GFS has a big storm as well.  The 0z early on the 24th, 6z run late on the 24th into 25th.

We are due for a big storm.  Haven't had a storm with over 1" of precip from a storm in one day since Nov 2.

Tuesday, December 4, 2018

December....where's the snow.

 12-11 GFS and NAVGEM are following suit with sliding the storm on the 14th, which was originally going to the lakes, now to our south.  We may get a feature dropping a dusting to an inch as trough slips in briefly.

Euro doesn't have this feature and instead develops the upper low into a surface low and sends out to sea (GFS does this as well, just faster.) Note how warm the Euro is.



12-9  The storm below stayed to the south.  Another storm is progged to go to the lakes on the 14th.  With a few other chances between now and the 25th.  The problem is its warm and they want to go to our west.


 The euro eps and operational  have a different solution for 12-14 timeframe

For the 14th-16th, the GFS ensembles are coming in closer to the NE, as is the FV3.  But too warm for snow.

12-4

We are coming out of a cold and stormy pattern in November and December looks a bit warmer and tamer, at least until the last week.  Currently watching a storm from the 9-11th time frame that looks to be headed to the south of CT, perhaps scraping coastal areas with some light accumulation.

 In the longer range, the EPS monthly has a storm up the EC around Christmas.

Tuesday, November 6, 2018

When will it snow!

11/6


Yes the season is upon us.  Christmas lights are out already and waiting for the snow to help bring us into winter.  First flakes last year were Nov 10.

The models have been showing sporadic chances for snow on some runs, but not until today do I feel it necessary to start talking snow.

0z GFS with its typical bias of pushing the storm and trough too fast
0z Euro with a more realistic solution, but the storm itself brings only a mix to deep interior NE
There's room for that to come back, but if it did it would rain.  
The 6z GFS showing it can be realistic. 
Now before we start stocking up,  I'm only expecting at most a wet snow with the low and even that is not likely, but I am expecting flurries and snow showers behind it, which should give us first flakes. Pattern after this quiets through Thanksgiving.  

Feb 25 clipper

 Got a quick 3" in 3 hours this morning Driveway was completely clear