January 24-26: Miracle or Mirage Thread 2

[Terpeast]

Just catching up. So the gfs didn’t fully cave, but pretty much all guidance met in the middle. I’d cut gfs accums by 75% though to account for ip/zr. That gets us to 6-10 for dc/balt metros, with a foot being in play for NW suburbs (1-2 counties off from I-95 and north of 50)

[psuhoffman]

1 minute ago, TSSN+ said:

Looks pretty dang cold to me 

 

If you look at the euro or 3k skew for the same time its surface temp is within 1 degree. The problem is the gfs cannot see the warm layer at 750mb. It’s not capable of it. This is a known problem. In cases where there is WAA and a mid level warm layer you have to adjust the snow/sleet line NW on the gfs. You can figure out where it should be a number of ways. Least technical is to look at the 3k or euro and say ok now if their Synoptics were identical to the gfs where would they have the snow/sleet line?  Then make the adjustment. If you use the GFS snow line in wAA situations you’ll be wrong EVERY SINGLE TIME. It won’t ever see the mid level warming.

Caveat…the only way we overcome the mid levels is if the precip is so heavy (death banded) that dynamic cooling can overcome a bit and the heavy precip can mix out the admittedly small warm layer all the better guidance has for our area. That’s not impossible but it wouldn’t be the gfs being correct it would a similar result for different reasons. 
 

like if you call a crossing route on 4th and goal from the 5 and the receiver falls down and the QB scrambles and breaks 2 tackles and dives into the end zone. Sure it ended up with a TD, same results, but when breaking it down in film study you wouldn’t say the play worked. 

[Solution Man]

3 minutes ago, Terpeast said:

Just catching up. So the gfs didn’t fully cave, but pretty much all guidance met in the middle. I’d cut gfs accums by 75% though to account for ip/zr. That gets us to 6-10 for dc/balt metros, with a foot being in play for NW suburbs (1-2 counties off from I-95 and north of 50)

75%?

[Terpeast]

2 minutes ago, Solution Man said:

75%?

Sorry, meant 25%. iow, use 75% of gfs values

[psuhoffman]

9 minutes ago, CAPE said:

Mt Holly only mentions snow and freezing rain in the forecast for here- no mention of sleet. Maybe they are taking the Euro verbatim with its freezing rain output. GFS has more significant sleet and less amounts of zr.

That seems lazy if true, not saying it is. If you look at the skew on the euro it’s clear their algorithm is just wrong and misidentifying  p type. It does have some legit freezing rain for you but it also is showing freezing rain for hours where there is a warm layer above 800mb and it’s like 22 at the surface.  Thats sleet. 

[CAPE]

12 minutes ago, Terpeast said:

Just catching up. So the gfs didn’t fully cave, but pretty much all guidance met in the middle. I’d cut gfs accums by 75% though to account for ip/zr. That gets us to 6-10 for dc/balt metros, with a foot being in play for NW suburbs (1-2 counties off from I-95 and north of 50)

Mount Holly going pretty aggressive here with the snow. Quite a range though so they cover their ass lol. 3-7 tomorrow night and 4-8 Sunday.

I would have 2-5" here Sunday and insert sleet into the forecast.

[Solution Man]

Just now, Terpeast said:

Sorry, meant 25%. iow, use 75% of gfs values

Got it, thanks 

[SomeguyfromTakomaPark]

For dc Euro looks like about 0.8 qpf as snow, and then 0.6 qpf as sleet. 6-10 of snow and a thick layer of sleet, that’ll be a high impact event if it verifies. 

[SomeguyfromTakomaPark]

NAM is only 0.4 qpf for dc pre flip, ive learned that when the NAM shows a mixing related disaster scenario, take it seriously.  Not saying its gonna happen, hopefully its still figuring out the Synoptics, but don’t write it off. 

[psuhoffman]

@TSSN+

All I’m saying is if you shave 2-3” off the GFS to account for it’s known issue not seeing mid level warmth these are all getting pretty close now. 
gfs

rgem

0z euro 

[Silver Meteor]

34 minutes ago, Weather Will said:

4 pm

Thank you for showing a Mid-Atlantic view. 

[dailylurker]

3 minutes ago, SomeguyfromTakomaPark said:

NAM is only 0.4 qpf for dc pre flip, ive learned that when the NAM shows a mixing related disaster scenario, take it seriously.  Not saying its gonna happen, hopefully its still figuring out the Synoptics, but don’t write it off. 

It's pretty clear that DC and east is going to be a massive sleet bomb. Such a bummer. Record cold and still can't snow lol. 

[snowfan]

Updated percentage chance of hitting or exceeding 8” snowfall before flipping. For reference, DCA is at the 50% threshold.

 

[snowfan]

5 minutes ago, dailylurker said:

It's pretty clear that DC and east is going to be a massive sleet bomb. Such a bummer. Record cold and still can't snow lol. 

That may be, but your backyard is still well within the 8-10” range before a flip. Of course that could still change, but you haven’t received that much in a single storm in 10 years. 

[GreyHat]

4 hours ago, goodwidp said:

Ha. They just released an updated one at 1:17am that is a tad more conservative. 

 

How do they come up with these maps? I ask because how it has that tear drop of 12" over Dover Delaware. I've never seen that before. 

[dailylurker]

Just now, snowfan said:

That may be, but your backyard is still well within the 8-10” range before a flip. Of course that could still change, but you haven’t received that much in a single storm in 10 years. 

I had almost 10" of cold smoke last January. No mix, no drama. Just a beautiful snow followed by cold. I'm just frustrated as always watching pa get crushed by our storm lol

[snowfan]

1 minute ago, dailylurker said:

I had almost 10" of cold smoke last January. No mix, no drama. Just a beautiful snow followed by cold. I'm just frustrated as always watching pa get crushed by our storm lol

That’s climo. 

[Terpeast]

3 minutes ago, snowfan said:

That’s climo. 

Yep. This is the kind of storm I've often seen when I was a kid. PA gets the most snow while we mix. I was jealous of State College then. But they've had a terrible, terrible run at snowfall in recent years. Like, worse than us.

[JenkinsJinkies]

38 minutes ago, Terpeast said:

That gets us to 6-10 for dc/balt metros

Fingers crossed Baltimore is still within striking distance of the ceiling.

[Benjamn3]

4 minutes ago, Terpeast said:

Yep. This is the kind of storm I've often seen when I was a kid. PA gets the most snow while we mix. I was jealous of State College then. But they've had a terrible, terrible run at snowfall in recent years. Like, worse than us.

 I was thinking the same. This reminds me of a few storms from the early 2000s. Models 72 hours out showed us getting crushed, ended up with about 4-8 with sleet. 

[snowfan]

 

 

[psuhoffman]

0z eps and 6zgefs both increased the 10% snowfall quite a bit across the area indicating the chances for a low end bust went down. The 10% snowfall on the EPS is still around 6” in DC and 9” up here. That’s a pretty decent “floor”. GEFS is significantly better of course but it also increases the floor. 

[JenkinsJinkies]

Just now, psuhoffman said:

0z eps and 6zgefs both increased the 10% snowfall quite a bit across the area indicating the chances for a low end bust went down. The 10% snowfall on the EPS is still around 6” in DC and 9” up here. That’s a pretty decent “floor”. GEFS is significantly better of course but it also increases the floor. 

Looking at the euro runs for 18z and 0z I’m thinking DC and surrounding areas get the floor, Baltimore and surrounding areas get the ceiling. So I think your area could get more than a foot.

[psuhoffman]

1 minute ago, JenkinsJinkies said:

Looking at the euro runs for 18z and 0z I’m thinking DC and surrounding areas get the floor, Baltimore and surrounding areas get the ceiling. So I think your area could get more than a foot.

Considering NWS has me in 18-24” “could get a foot” seems reasonable. I’d go 8-12 for my area no idea what NWS is smoking. 

[mappy]

Happy Friday weenies 

[Solution Man]

2 minutes ago, BristowWx said:

damn brother.  you are bringing the heat...or cold.  you and Will are burning the candle at both  ends.  

Got some sleep,  @Weather Willbrings the heat daily

[mappy]

My point and click has added snow to Sunday night now 

Saturday night  3-5

Sunday 7-11

Sunday night 2-4

[DDweatherman]

9 minutes ago, psuhoffman said:

Considering NWS has me in 18-24” “could get a foot” seems reasonable. I’d go 8-12 for my area no idea what NWS is smoking. 

I think I like 10-15” for your backyard, and I SHOULD be far enough n/w for 12-18” (wishful thinking?) 

[mappy]

I was hoping the warm layer would have eased on overnight runs, but was just a dream. Sleety up here by mid afternoon Sunday. 

[mappy]

1 minute ago, DDweatherman said:

I think I like 10-15” for your backyard, and I SHOULD be far enough n/w for 12-18” (wishful thinking?) 

I think we are all good for a foot before a flip. more for you, PSU, highstakes, Mitch, tssn, etc. it wouldn’t surprise me if yall stay pure snow while I sleet