March 5-6 Storm Discussion

[BIG FROSTY]

Pretty decent def. band!

[Shawn]

I will take it, flurries it is!

 

Yeah, don't take that map totally seriously.  I think some melting is accounted for there.  All these snow maps look different.

 

EDIT, I should have posted the snowfall maps instead of depth.  I'll let someone get Allan's site maps in a bit instead.

[Cold Rain]

I still blame the PAC for being the ghost in the machine for two straight winters.  I've obviously done better this year, but as I stated last week, I do not trust those extreme solutions in such a fast flow.  

 

Yeah, it's bad.  We're in a super -PDO regime, so expect it to continue, with the occasional break, for a few years yet.

[NCSNOW]

http://www.americanwx.com/bb/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=92229'>ukarky.gif

Ill take the Euro ensembles, op and ukmet all day long at this range verse the American models.

[Brick Tamland]

WxSouth still saying significant snow extends down to NC.

[superjames1992]

0Z GFS clown actually better than the 18Z version for Superjames to Charlotte. Superjames gets 4" on 0Z vs. <1" on 18Z. Charlotte ~1" 0Z vs. very little on 18Z.

 

Pretty nice deformation band going on in the northwestern Piedmont this run.  If the "worst" model is giving me 4", maybe things aren't so bad.

 

I'm nowhere near giving up.  The Euro, Euro Ensembles, UK Met, GGEM, etc. still look pretty solid for this area, too.

[griteater]

I see the UKMet out to 96 on the neck wrenching French site...doesn't looked like it's budged for 3-4 straight runs...it's the farthest south, but that's also a known bias of the UKMet

[Shawn]

I see the UKMet out to 96 on the neck wrenching French site...doesn't looked like it's budged for 3-4 straight runs...it's the farthest south, but that's also a known bias of the UKMet

These COULD be outdated, but:

 EDIT, list was updated in 2000 on NOAA site, so yeah.. grain of salt.

UKMET

• Has problems with shallow cold air.
• Tends to progress shorter wavelength features too quickly.
• Westerlies are often too far south.
• The model tends to lower surface pressures too much and too far south and often implies synoptic-scale fronts too far south.
• Often too low with heights along the southern ends of short wave trofs, resulting in a southward displaced storm track
• Significant low pressure bias during the warm season over the western U.S., particularly when upper ridge conditions predominate
• Breaks down amplified long wave patterns too quickly
• Over the east, tends to be too weak and strung out with surface cyclogenesis along fronts when a significant short wave is digging into the trough position. This results from the forecasted baroclinic zone being too broad and low-level temperature gradients being too weak. (Doesn't take into account latent heat release from the Gulf Stream).
• Of the medium range models, it has the poorest performance forecasting polar vortices.
• Often is too flat with the upper and surface patterns over the western Pacific.
• Eastward forecast bias with upper lows, especially over eastern Canada, possibly due to its tendency to flatten amplified patterns too quickly
• The UKMET often develops an upper system too far to the south over the Gulf of Mexico and the northwest Caribbean. This is a tropical interaction problem or applies directly to tropical cyclones.

 

From Pennstate Ewall:

 

 

Model Biases

One general bias of the UKMET model is that it tends to place weather features too far south. The model tends to position storms too far south since the Westerlies on the model are often located too far to the south. Also the model is often too low with heights along the southern end of short wave troughs, which results in a storm track that is often too far south.

Some other basic model biases of the UKMET model are that the model has a problem grasping shallow cold air and tends to progress shorter wavelength features too quickly. The model also has a tendency to break down amplified long wave patterns too quickly. One major problem with the UKMET model is that it tends to be very weak with surface cyclogenesis along fronts when a large short wave is digging into a trough. The result of this is that the model tends to be too weak with low-level temperature gradients and too broad with the forecasted baroclinic zone. Out of the all the medium range forecast models; this model has the poorest performance when it comes to forecasting polar vortices.

One benefit of the UKMET model is that it seems that the model does fairly well in forecasting the phasing of systems in the northern and southern branches of the jet stream across the northern hemisphere.

[BIG FROSTY]

Ill take the Euro ensembles, op and ukmet all day long at this range verse the American models.

Me too! I said it back a few post I put much more weight on the Euro.. Now it may go north tonight so be it, it still gets more credit at this stage of the game. IMO

[beanskip]

Ukie has 850 low over the area where the Ind/Ill/Ky border intersect at 72 hours.

GFS has it well to the NE -- at the central border of Ind. and Ohio.

NAM has it up on Ind/Mich border.

 

Looks like the envelope might be 'rewidening' ...

[SN_Lover]

forum drama... lol but in all honesty some part of NC may still get some snow...may not be the foot of snow models were predicting a few days ago, but it's something at least. northern nc should get at least light accumulations. 

[Brick Tamland]

Ill take the Euro ensembles, op and ukmet all day long at this range verse the American models.

 

Foreign models look a lot better for NC. And that's three against two. 

[NCSNOW]

Pretty decent def. band!

it'd be a lot prettier if it where 50 - 75 miles further south. One noteworthy item about that map is it screws 2 well known mets over big time. One is in Richmond seeing heavy rain and the other is in PA getting a hundredth of an inch qpf s she heads OTS.

[BIG FROSTY]

it'd be a lot prettier if it where 50 - 75 miles further south. One noteworthy item about that map is it screws to well known mets over big time. One is in Richmond seeing heavy rain and the other is in PA getting a hundredth of an inch qpf s she heads OTS.

Yep didn't notice that. lol

[beanskip]

Looks like main difference on Ukie is it has one consolidate low (a la WeatherNC) vs. the secondary.

[Pilotwx]

For my area I like this run some of this is using you knowledge of how your area can get snow. I like the set-up for triad area and NW and West still see a huge potential for a lot of NC people to see snow. Our terrain to the West will ring out more moisture than what is being modeled. Low gets a going east of Rah. If this thing is stenghting it is going to pull more cold air down closer to the storm also.

[superjames1992]

The UK Met looks pretty good for us NC folks.  It has been consistent lately.

[LovingGulfLows]

I hope people in NC aren't complaining about getting 3-4 inches compared to 8+ modeled a few days back. Us down here in Atlanta would love to get any type of accumulating snow at this point.

[packbacker]

GGEM very similar to the GFS but does seen to wrap more moisture around back into central NC.

[NCSNOW]

I always gain a lot of confidence hanging my hat on a model that's upside down.

[chapelhill]

I guess there is always something. It's getting so it doesn't even matter what happens until 24 hours out. It never seems to work out for us if it looks good in the long range.

Well, its definitely not 24 hours out yet . Keep on keepin' on.

[NCSNOW]

GGEM very similar to the GFS but does seen to wrap more moisture around back into central NC.

Low is off the crystal coast/ Morehead as opposed to Norfolk. Huge difference in sensible weather.

[superjames1992]

I don't know, guys; I'm just not feeling that down right now.  The GFS is finally picking up on a stronger deformation band and the UK Met and GGEM haven't budged.  If the Euro stays the same or comes south tonight, I'm going to be pretty optimistic.

 

NOTE: Optimism is a known bias of this poster.

[Marion_NC_WX]

I hope people in NC aren't complaining about getting 3-4 inches compared to 8+ modeled a few days back. Us down here in Atlanta would love to get any type of accumulating snow at this point.

 

 

The 500 mb low track is just south of the NC/VA border...I think the area of getting 3-4 or more is going to be limited to the high country just due to the higher elevation. And maybe the northeast tip of North Carolina if that deformation band is as strong as the model is showing.

 

With the terrible positioning of the 500mb energy, a large majority of North Carolina is gonna get downsloped quickly once is moves east. I'm not buying into that deformation zone being down into NC with the positioning of the energy.

[Disc]

I don't know, guys; I'm just not feeling that down right now.  The GFS is finally picking up on a stronger deformation band and the UK Met and GGEM haven't budged.  If the Euro stays the same or comes south tonight, I'm going to be pretty optimistic.

 

The euro will be very telling tonight and I'm anticipating it more than the GFS.. GFS was definitely colder and had better precip especially with the deform band pushing into northwestern NC. I need to check soundings for ROA though because the meteograms were spitting out .50" of freezing rain then 8" of snow on top here on the 18z ..

[packbacker]

I think that was last nights run.

[calm_days]

 

I am seeing that the southern component about to come onshore looks fairly well-defined. 

 

Here is an animation of course!

http://www.ssd.noaa.gov/goes/west/weus/loop-wv.html

 

I am not exactly sure about the northern energy: the southern energy looks like a bowling ball bud whereas the northern circulation looks like it has less control over the shape of the huge water vapor plume than the southern. 

 

Looking at the 24-hour water vapor loop here, http://preview.weather.gov/edd/

I see how a specific modulation of the ULL west of this energy coming on shore interacted with that part of the plume to shape the southern energy into something.

[BIG FROSTY]

I think that was last nights run.

You may be right sorry!

[Disc]

CMC has a ton of rain on the onset even for most of Virginia. Looks like the initial low is cranking over Indiana and then transfers it to NC then drifts into VA and stalls out over RIC.

 

[mclean02]

So gso is done then? Well we had a good run lol