February 12-13 Storm, Part III: Trilogy ends and then Obs thread soon!

[Bari]

a good 24 hour event

[dtk]

Cool, but you might wanna take that up with the forecaster who said it.

 

I was just stating that vinyl and some others might not have been off and on the usual weenie excuse of convective feedback, give than someone in the know offered the same opinion.

 

I don't hate the GFS.

I explicitly stated that I fully expect the GFS to be wrong.  I would be making the same arguments if it was the NAM, ECMWF, or other model showing the same thing.

 

We do have regular meetings on model evaluation and are working hard to bring developers and forecasters closer together.  A lot of operational forecasting folks don't have intimate knowledge about NWP, data assimilation, etc. (nor should we necessarily expect them to).  I was just offering my perspective and opinion....take it for what it's worth, you're free to ignore me.

[Deck Pic]

NAM Is like 8" of snow for DC with probably 2" in the afternoon/evening.....~10".....ends at 8pm or so...nice 24 hour event

[PDIII]

Agree, it's all induced by a fall in uvv and proximity of dry slot. If we're sitting under 20+ dbz with a NW wind it's still likely snow at 31-33 surface.

Thats why I am not to worried about these warm solutions... looks like the change over period is just drizzle...and then the back side potential looks to be real.... 

[yoda]

According to the HI-RES, 06z to 15z is a shellacking on the MSLP/850 map

[eurojosh]

NAM Is like 8" of snow for DC with probably 2" in the afternoon/evening.....~10".....ends at 8pm or so...nice 24 hour event

 

Seems to come back for a bit more back end... really ends (per the nam) around 1am...

[stormtracker]

I explicitly stated that I fully expect the GFS to be wrong.  I would be making the same arguments if it was the NAM, ECMWF, or other model showing the same thing.

 

We do have regular meetings on model evaluation and are working hard to bring developers and forecasters closer together.  A lot of operational forecasting folks don't have intimate knowledge about NWP, data assimilation, etc. (nor should we necessarily expect them to).  I was just offering my perspective and opinion....take it for what it's worth, you're free to ignore me.

Not sure why you think I'd ignore you, but alright.  I happen to enjoy  your insight on the models, I just think you may have taken my comment as directed at you or something.   I don't know enough about NWP to ignore anybody. 

[vinylfreak89]

I am pleasantly surprised the models are beginning to resolve the deform band. Consensus looking good for a shellacking. Usual stress could see upwards of 20" in the prime of deformation axis.

[Deck Pic]

At a doctors appointment and hate to weenie like this but how does the back side look on the NAM?

Very impressed by the pbp so far.

 

decent...not great..none of the models look amazing, but I'd say you get 2" with the backside...it is a tough forecast for tomorrow....rain seem unlikely for DC and NW.....sleet is the better call for say late morning through mid afternoon...then back to snow.....soundings at 12z and 15z are way better than you might think....18z and 21z are sleet soundings...unless you really believe that we are getting rain with 850 temps of 0.5 or so.....or that you think they will even really warm above 0

[HighStakes]

I think it's somewhat say this will be a 24 hour event. Yesterday at this time some models especially the NAM had the precip leaving the area shortly after 18z. That is no longer the case.

[H2O]

NAM Is like 8" of snow for DC with probably 2" in the afternoon/evening.....~10".....ends at 8pm or so...nice 24 hour event

If we cash in at the beginning then the rest is gravy.  More is better but until the mixing issue is resolved(which will only happen during the storm) that initial thump is where its at.

[weathercoins]

I bet LWX ups the snow totals in the warning statements later this morning. 4 to 8 for DC/suburbs seems a bit too conservative, even just from the pre-sleet initial thump.

[Kmlwx]

decent...not great..none of the models look amazing, but I'd say you get 2" with the backside...it is a tough forecast for tomorrow....rain seem unlikely for DC and NW.....sleet is the better call for say late morning through mid afternoon...then back to snow.....soundings at 12z and 15z are way better than you might think....18z and 21z are sleet soundings...unless you really believe that we are getting rain with 850 temps of 0.5 or so.....or that you think they will even really warm above 0

Thanks!

Even if the back side isn't great... I'm sure I'll be high on life if this front side is like 8 or 10 inches.

[EasternUSWX]

RAP out far enough to show incoming shellacking.

 

[SomeguyfromTakomaPark]

Just push that deform band a little to the right and tomorrow afternoon and evening will make a lot of I95 people happy

[Bob Chill]

Highres through 7am. I'm not sure we could ask for much better. Looks pretty awesome to me. 

 

 

[stormtracker]

Highres through 7am. I'm not sure we could ask for much better. Looks pretty awesome to me. 

 

 

hres7am.JPG

If the NAM's qpf numbers are right, I'd say some of the calls I'm seeing on TV and NWS are on the conservative side.

[Deck Pic]

If we cash in at the beginning then the rest is gravy.  More is better but until the mixing issue is resolved(which will only happen during the storm) that initial thump is where its at.

 

Hi Res shows the evolution well...we get raked until 10am....is some of that sleet?...maybe me and you mix...I am not confident we do a full flip for very long but maybe that is wishful thinking

 

From 10-4pm we lull with light rain/sleet/snow/drizzle etc.....as the precip picks back up, from 4-10 we flip to moderate snow and get a solid 4+ hours of snow....probably tacking on another 2", maybe 3"....

[HM]

This could be a high ratio punch in the face where it's maximized in frontogen bands at 2-3"/hr within the broad shield.

[Bob Chill]

This could be a high ratio punch in the face where it's maximized in frontogen bands at 2-3"/hr within the broad shield.

 

I was thinking about that. It could be really hot and heavy for a time overnight. Flirting with sleet line is never a bad thing in our parts with a coastal. 

[yoda]

Hi Res shows the evolution well...we get raked until 10am....is some of that sleet?...maybe me and you mix...I am not confident we do a full flip for very long but maybe that is wishful thinking

 

From 10-4pm we lull with light rain/sleet/snow/drizzle etc.....as the precip picks back up, from 4-10 we flip to moderate snow and get a solid 4+ hours of snow....probably tacking on another 2", maybe 3"....

 

850's stay east enough for us... but barely looks like... I am going to assume if the precip is heavy enough like the hi-res shows it should be snow... prob tapering to sleet 10am or so after

[Deck Pic]

This could be a high ratio punch in the face where it's maximized in frontogen bands at 2-3"/hr within the broad shield.

 

yup...I'm ready

[Bob Chill]

It's awful close between 7am-10am but if we held on verbatim with the nam model, here's the totals through 10am. VERY impressive. 

 

[HM]

I was thinking about that. It could be really hot and heavy for a time overnight. Flirting with sleet line is never a bad thing in our parts with a coastal.

You guys are saturated to the strat with omega throughout the mid levels. Maybe someone with bufkit can comment, but I don't see a lot to stop the dendrite unloading at peak forcing. Arguably, the dendritic zone is a little high, giving flakes time to alter/rime but meh...

[mattie g]

According to the HI-RES, 06z to 15z is a shellacking on the MSLP/850 map

 

Yeah, the HI-RES is a smackdown all morning.

[HM]

yup...I'm ready

That west NAO signal always sends the threats to you guys. Let's hope it works out!

[astarck]

Point and click for DC looks like it was upped slightly, no?

 

 

 

• Tonight Snow. The snow could be heavy at times. Low around 26. North wind 7 to 13 mph, with gusts as high as 23 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
• Thursday Snow before noon, then snow and sleet between noon and 3pm, then snow after 3pm. The snow could be heavy at times. High near 34. North wind 13 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New snow and sleet accumulation of 2 to 4 inches possible.

[RevWarReenactor]

I wonder if we switch to rain, that actually could be bad. If temps crash into the 20's Thur night the snow could freeze solid like a block of ice. The type where you can stand on top of it and its impossible to move. Ala March 1993.

[Deck Pic]

850's stay east enough for us... but barely looks like... I am going to assume if the precip is heavy enough like the hi-res shows it should be snow... prob tapering to sleet 10am or so after

 

it's the warm nose at 900-925mb that we need to be worried about....it is a very shallow layer and so close to freezing not sure we get PD2 style driving sleet...that was an inversion layer above 850mb anyway which is harder to combat.....that happens to us mid morning...we get a warm layer above...it is much less likely to get snow when you have that....a tiny warm nose at 900mb?...f-uck that...we can snow through that...

[Bob Chill]

You guys are saturated to the strat with omega throughout the mid levels. Maybe someone with bufkit can comment, but I don't see a lot to stop the dendrite unloading at peak forcing. Arguably, the dendritic zone is a little high, giving flakes time to alter/rime but meh...

 

We're all pretty pumped about the front end threat here. It's been so long since we had area wide +SN. I doubt many hardcore or even casual weenies will be sleeping tonight. I'm napping after the euro. lol