February 10-12, 2019 Storm

[arlwx]

The latest from LWX:

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Sunday starts out fairly benign, with perhaps only some
increasing high clouds suggesting the change of the weather
which will be approaching. Depending on how long the sun lasts,
temps may get stuck in the 30s, or could sneak into the 40s.

By late afternoon, warm advection ahead of the first disturbance
combined with jet forcing from a streak to our northeast should
combine to start causing precip to break out across the region,
though dry low levels likely keep most areas dry until after
sunset. Temperatures aloft are extremely tricky this time
around, with many models showing a warm tongue - however, its
location, position and strength will make a lot of difference.
If a heavier band of precipitation moves through, the column may
cool and we could see more snow than we are currently
predicting Sunday night, while weaker precip would allow
rain/sleet and freezing rain to prevail in the areas where the
warm layer is relatively weak. After the initial wave,
additional weak impulses and continued warm advection/fgen aloft
may keep light precip around much of the day Monday before a
stronger surge of moisture and forcing ahead of the second,
stronger low pressure system bring steadier and heavier precip
across the region Monday night.

Given timing and type uncertainties, for the time being we are
keeping the forecast relatively general, with light amounts of
snow/sleet followed by some potential for freezing rain Sunday
night into Monday with the first wave, then additional freezing
rain and sleet (and perhaps a little snow near the Mason/Dixon
line) later Monday into early Tuesday as the stronger wave of
low pressure lifts northeastward to our northwest. As far as
impacts, the best bet for them is during the Monday morning
commute, with lesser odds for the evening commute (given mainly
lighter precip during the day, potential for some warming during
daylight, and crews being able to get out and treat the roads).
High uncertainty regarding Tuesday morning`s commute exists
given potential for cold air to get drawn back south Monday
night, especially north and west of the I-95 corridor. Advisory
level snow/ice is generally expected across much of the forecast
area, keeping in mind the ice threshold is very low and the snow
threshold during rush hour in the metro is also quite low. That
said, at this time, while nothing can be ruled out, we are not
explicitly forecasting warning level snow or ice. However, if a
band of heavier snow developed, or if the cold air drains back
south while heavier precip is moving in Monday night, warning
level snow/ice would be quite possible. Temps through the short
term will remain generally below normal during the day, and near
normal at night, with areas north and west of I-95 having
trouble getting above freezing Monday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
On Tuesday a mid to upper level trough will be over the Midwest
while a low pressure system is at the surface. This system will
be moving NW as a warm front associated to it will lift north
over our CWA through the day Tuesday, followed by a cold front
on Tuesday night. Widespread precipitation during this time is
possible. It may start as a wintry mix of precip early on
Tuesday, but there may be enough warm air to see all rain.
Wintry mix could return Tuesday night before precipitation moves
away from our area along with a cold front.

High pressure builds from the southwest on Wednesday and
remains in control into Thursday. The next weather system to
watch for approaches on Friday bringing precipitation over our
region, with the potential for rain and/or snow.
 

[psuhoffman]

3 hours ago, NorthArlington101 said:

EURO is moderate ice for N/W of DC and decent snow in N MD. Better run than 12z.

 

Better????

12z op

0z op

12z eps

0z eps 

 

[psuhoffman]

I want this back...

But now we have...

unfortunately the upper level pattern supports the second solution there. I can’t find any analogs with significant warning level snowfalls with a west based -epo, -pna  without major blocking or a displaced Tpv. The upper air analogs to this week were really bad. No real snowstorms near the dates for any of them. Best in the lot were a couple nuessance 1” slop events. 

I don’t know why from range models like to push the boundary too far south in a -epo/-pna pattern but they do. General rule if there isn’t a strong block, a displaced tpv to our north, or the epo isn’t centered into western Canada, storms will adjust NW and the favored track is cutting to the lakes. 

[CAPE]

13 minutes ago, psuhoffman said:

I want this back...

But now we have...

unfortunately the upper level pattern supports the second solution there. I can’t find any analogs with significant warning level snowfalls with a west based -epo, -pna  without major blocking or a displaced Tpv. The upper air analogs to this week were really bad. No real snowstorms near the dates for any of them. Best in the lot were a couple nuessance 1” slop events. 

I don’t know why from range models like to push the boundary too far south in a -epo/-pna pattern but they do. General rule if there isn’t a strong block, a displaced tpv to our north, or the epo isn’t centered into western Canada, storms will adjust NW and the favored track is cutting to the lakes. 

Only thing this really had going for it was the vortex in the 50-50 region and the second lobe rotating underneath enhancing confluence. The surface high is on the move though. If the initial wave were juiced up more, there probably would be a decent period of snow/sleet, esp up your way. It is inevitable though with the trough out west and no blocking the main event is, and always was, going to be a mild cutter.

[psuhoffman]

8 minutes ago, C.A.P.E. said:

Only thing this really had going for it was the vortex in the 50-50 region and the second lobe rotating underneath enhancing confluence. The surface high is on the move though. If the initial wave were juiced up more, there probably would be a decent period of snow/sleet, esp up your way. It is inevitable though with the trough out west and no blocking the main event is, and always was, going to be a mild cutter.

But 3-4 days ago most guidance kept the wave under us. Look at that gfs I posted above.  At the time euro and fv3 agreed. People are saying that now because as the look started to degrade they began to cling to what snow options were left and for a time the hope of some frontrunning waa wave was all they had. But the problem with that is nothing can amplify into the ridge so a weak wave will wash out. A strong one will cut. It’s just a bad upper level pattern.  We can luck our way to 1-2” in any pattern in mid winter. I don’t even waste my time on identifying patterns for that. But the look next week is flat awful for anything of significance.  But Ralph loves a -epo-pna gradient pattern so there’s that!!!

[CAPE]

Just now, psuhoffman said:

But 3-4 days ago most guidance kept the wave under us. Look at that gfs I posted above.  At the time euro and fv3 agreed. People are saying that now because as the look started to degrade they began to cling to what snow options were left and for a time the hope of some frontrunning waa wave was all they had. But the problem with that is nothing can amplify into the ridge so a weak wave will wash out. A strong one will cut. It’s just a bad upper level pattern.  We can luck our way to 1-2” in any pattern in mid winter. I don’t even waste my time on identifying patterns for that. But the look next week is flat awful for anything of significance.  But Ralph loves a -epo-pna gradient pattern so there’s that!!!

I do recall that 18z run but I guess looking at h5 I never bought it. I haven't had a lot of time lately to pore over each model cycle, but IIRC guidance was holding back the main energy even when they had the good CAD look. That was a hint of what was coming. Like you said, and the analogs back it up- the overall long wave pattern is simply unfavorable for snow here. Great for the upper MW.

[psuhoffman]

6 minutes ago, C.A.P.E. said:

I do recall that 18z run but I guess looking at h5 I never bought it. I haven't had a lot of time lately to pore over each model cycle, but IIRC guidance was holding back the main energy even when they had the good CAD look. That was a hint of what was coming. Like you said, and the analogs back it up- the overall long wave pattern is simply unfavorable for snow here. Great for the upper MW.

This week doesn’t bother me much. Phase 6/7 isn’t a good look. This is about what should happen. I’ve tried not to deb on it when models were spitting out pretty snow maps and people wanted to believe but I never had much hope before the 20th. But if we get phase 8/1 and a -soi and the trough stays out west and we get cutters the following week, hide all the cute furry animals!!!

[MillvilleWx]

19 minutes ago, psuhoffman said:

This week doesn’t bother me much. Phase 6/7 isn’t a good look. This is about what should happen. I’ve tried not to deb on it when models were spitting out pretty snow maps and people wanted to believe but I never had much hope before the 20th. But if we get phase 8/1 and a -soi and the trough stays out west and we get cutters the following week, hide all the cute furry animals!!!

Bunnies are pretty extinct in the Rockville area after December. Should be good up your way though. Just watch out for Bambi

[psuhoffman]

11 minutes ago, MillvilleWx said:

Bunnies are pretty extinct in the Rockville area after December. Should be good up your way though. Just watch out for Bambi

Lol. What’s your take long term?  Why does the trough want to get stuck out west on guidance despite every favorable tele to a trough in the east? 

[MillvilleWx]

1 minute ago, psuhoffman said:

Lol. What’s your take long term?  Why does the trough want to get stuck out west on guidance despite every favorable tele to a trough in the east? 

We were talking about it at the other day at work. We think the MJO/SOI is just ruling the roost for the entire longwave pattern. It's unusual to have something dominate like it has, but that's really the only thing we can come up with. The Nino not budding like what was projected has also shifted focus to other teleconnections with very little influence over the pattern. We've been skipped over all winter down here, which is unusual for a Nino. In fact, going back, we don't really have much of an analog for what has transpired. It's like a mixture of a few, but we had normal precip in those years. I'm not a long range guy, I love the mid and short term. That's part of the reason I rarely interject in the long range thread. It's like pulling teeth, and I'm more of a shooting fish in a barrel kind of guy lol

[CAPE]

29 minutes ago, MillvilleWx said:

Bunnies are pretty extinct in the Rockville area after December. Should be good up your way though. Just watch out for Bambi

Too many Bambis around here. Lots of road slaughter.

[psuhoffman]

8 minutes ago, MillvilleWx said:

We were talking about it at the other day at work. We think the MJO/SOI is just ruling the roost for the entire longwave pattern. It's unusual to have something dominate like it has, but that's really the only thing we can come up with. The Nino not budding like what was projected has also shifted focus to other teleconnections with very little influence over the pattern. We've been skipped over all winter down here, which is unusual for a Nino. In fact, going back, we don't really have much of an analog for what has transpired. It's like a mixture of a few, but we had normal precip in those years. I'm not a long range guy, I love the mid and short term. That's part of the reason I rarely interject in the long range thread. It's like pulling teeth, and I'm more of a shooting fish in a barrel kind of guy lol

Agreed but the soi is about to tank and the mjo goes unti high amplitude 8/1 which correlate to a deep eastern trough yet the long range guidance wants to keep a SE ridge. That’s the part that has me confused. 

[MillvilleWx]

5 minutes ago, C.A.P.E. said:

Too many Bambis around here. Lots of road slaughter.

I drive that area sometimes to get to my parents using the back way and avoiding Rt 50. It's crazy how many deer roam that area. 

[MillvilleWx]

1 minute ago, psuhoffman said:

Agreed but the soi is about to tank and the mjo goes unti high amplitude 8/1 which correlate to a deep eastern trough yet the long range guidance wants to keep a SE ridge. That’s the part that has me confused. 

Yeah. That part is pretty abnormal. Like I said, we have really haven't seen much like this in the past for down here. It's an anomaly that will need to be further investigated to put all the pieces together. I think guidance will adjust with the SOI and MJO progression and dampen the SE ridge over the next week, but some remnant version will stick in place is my feeling. We're kind of in a tough spot here because spring is approaching and we've missed on multiple good rain chances to our north. That's going to put us in a rare spot where a slight positive ENSO might exhibit an average to above average Fire Wx season. Trough along the PAC coast doesn't want to help us at all outside of some wind. 

[showmethesnow]

For those that saw the latest EPS snowfall maps and their withdrawing the snow northward thought it indicated weaker CAD I don't think that was necessarily the case. The setup with the High to the north actually looked a touch more favorable. I think what we are seeing with the reductions of the snowfalls lies elsewhere. 

Could throw up a bunch of different maps but I think these two (12z + 00z eps total precip) probably best show the issue here in a general way. First the circled areas through southern MD are precip that fell with our initial impulse Sun so just ignore that. What I want you to take note of are the heavy totals to the west. What we have seen is a slight adjustment northward on the latest run. So what this basically means is that with the 12z's run we were having a better influx of initial moisture/rates for the more southern portions of our region (Dc/S MD) with the WAA. But with the latest runs shifting of the precip maxes northward the better moisture and rates have shifted north as well for this initial slug of moisture. These better rates are needed to cool the column down and in such a marginal setup, especially with temps to the south, this means a world of difference between snow/no snow.

 

 

 

 

 

[paxpatriot]

I mean, someone said this yesterday, but the Ukie continues to show basically the exact same result each time. Maybe consistently wrong, but impressive anyway.

[Wonderdog]

I'm gonna hang with the CMC for our upcoming storm. Looks like some snow and pretty good CAD showing up on the 0z run.

 

[snowmagnet]

33 minutes ago, showmethesnow said:

For those that saw the latest EPS snowfall maps and their withdrawing the snow northward thought it indicated weaker CAD I don't think that was necessarily the case. The setup with the High to the north actually looked a touch more favorable. I think what we are seeing with the reductions of the snowfalls lies elsewhere. 

Could throw up a bunch of different maps but I think these two (12z + 00z eps total precip) probably best show the issue here in a general way. First the circled areas through southern MD are precip that fell with our initial impulse Sun so just ignore that. What I want you to take note of are the heavy totals to the west. What we have seen is a slight adjustment northward on the latest run. So what this basically means is that with the 12z's run we were having a better influx of initial moisture/rates for the more southern portions of our region (Dc/S MD) with the WAA. But with the latest runs shifting of the precip maxes northward the better moisture and rates have shifted north as well for this initial slug of moisture. These better rates are needed to cool the column down and in such a marginal setup, especially with temps to the south, this means a world of difference between snow/no snow.

 

 

 

 

 

So you’re saying there’s a chance....

[Chris78]

12 minutes ago, paxpatriot said:

I mean, someone said this yesterday, but the Ukie continues to show basically the exact same result each time. Maybe consistently wrong, but impressive anyway.

It's seems that the ukie hasn't amped up systems enough this winter, causing it to produce white not wet outcomes for our area. Especially since we've been on the southern edge.

The storm back in January that  along M/d  line received an inch or so and then a deluge of rain , the ukie was calling for a 1' + 24 hours to go time

 

[MD Snow]

Agree with LWX. If we can get a good slug of moisture coming through Sunday night temps would drop and could get interesting. 12k nam has temps around freezing with dews in the teens at 0z Monday for much of the area as precip moves in. We need to be rooting for that precip to come in thumping. It’s looking like it is quickly becoming our only shot with this system. 

[osfan24]

I feel like the Ukie has been terrible the past couple of years. It'll show a solution and sometimes stick with it for awhile and then suddenly make a huge jump. I expect that with this.

[dallen7908]

Gradient pattern FTL? Forum Civil War?: Over the next 96 hours, 76% of 00UT EPS members give Westminster > 3" while only 6% of the members give Upper Marlboro  the same. 

[MD Snow]

It’s hard to ignore the warming trend across all guidance over the last 24 hrs. If that trend doesn’t stop today there is no reason to think that many in this sub will see mainly rain. Sunday night-Tuesday. 

[poolz1]

06z euro looks better for MD Line.  

[NorthArlington101]

Better????

This is probably why I shouldn’t post at 1:00am coming back from a house party, but I coulda sworn it showed more wintery precip (FRZA) than at 0z. I’ve personally given up on seeing snowfall, so an expansion of anything wintery southward is a win for me.

[Solution Man]

2 minutes ago, NorthArlington101 said:

 

This is probably why I shouldn’t post at 1:00am coming back from a house party, but I coulda sworn it showed more wintery precip (FRZA) than at 0z. I’ve personally given up on seeing snowfall, so an expansion of anything wintery southward is a win for me.

 

Keep enjoying the house parties especially tonight. Need u to drag that line South 

[BaltimoreWxGuy]

10 minutes ago, losetoa6 said:

Rgem bullish for round 1 

Not a surprise since the Canadian has been 

[Chris78]

6 minutes ago, poolz1 said:

06z euro looks better for MD Line.  

If we want any chance at seeing accumalting snow we really need to reverse the trends and that's a nice start. Needs to sag another 50 miles or so.

I'm afraid another model cycle or so and it will be a shut out for the entire forum.

[Chris78]

9 minutes ago, poolz1 said:

06z euro looks better for MD Line.  

How much of that falls with round 1?

[aldie 22]

Today is when the CAD strength gets noticed....book it