February 10-12, 2019 Storm

[psuhoffman]

Yoda does the UK still look "decent"?

[yoda]

17 minutes ago, psuhoffman said:

Yoda does the UK still look "decent"?

Sure... if you want to believe the snow map lol

[WesternFringe]

59 minutes ago, SnowGolfBro said:

While the snowfall output is fun to laugh at it does show how the CAD could be significant enough to at least get decent frozen as far South as Fredericksburg. And how our MD friends could get a significant snow/sleet/ice event

It also shows how CAD may help out here in the Shen Valley at elevation, which is why I haven't yet totally given up on this storm.  Low around 12 tonight per NWS.  Hoping the cold has some lasting power.

[BaltimoreWxGuy]

Euro still looks pretty aggressive on the snowfall map. IF I get 5” from this I’d be estatic 

[NorthArlington101]

[dsnowman]

Two things. The globals are still not picking up on the CAD as evidenced by both the latest Euro and NAM(s) depicted above. Forecasted (and therefore modeled) temperatures are coming in 2-3 degrees colder for both Saturday highs and tonight’s lows across DC metro area. This is a cold airmass. And with cloud cover rolling in Sunday afternoon I doubt we reach the forecasted low/mid 40’s for DC metro area. I think we could be in for a surprise at least Sun into Mon with snow/ice for DC metro.

[arlwx]

WWAs are up.

URGENT - WINTER WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
302 AM EST Sun Feb 10 2019

MDZ003>006-011-014-501>508-VAZ028-031-505-WVZ050>053-055-501>504-
102000-
/O.NEW.KLWX.WW.Y.0010.190211T0000Z-190211T1500Z/
Washington-Frederick MD-Carroll-Northern Baltimore-
Southern Baltimore-Anne Arundel-Extreme Western Allegany-
Central and Eastern Allegany-Northwest Montgomery-
Central and Southeast Montgomery-Northwest Howard-
Central and Southeast Howard-Northwest Harford-Southeast Harford-
Frederick VA-Clarke-Western Loudoun-Hampshire-Morgan-Berkeley-
Jefferson-Hardy-Western Grant-Eastern Grant-Western Mineral-
Eastern Mineral-
302 AM EST Sun Feb 10 2019

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM THIS EVENING TO
10 AM EST MONDAY...

* WHAT...Snow, sleet and freezing rain expected. Total snow
  accumulations of 1 to 2 inches and ice accumulations of less
  than a tenth of an inch expected.

* WHERE...Portions of central, northern and western Maryland,
  northern Virginia and eastern West Virginia.

* WHEN...From 7 PM this evening to 10 AM EST Monday.

---

URGENT - WINTER WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
302 AM EST Sun Feb 10 2019

DCZ001-MDZ013-VAZ025>027-029-030-036>040-050>054-501>504-506>508-
WVZ505-506-102000-
/O.NEW.KLWX.WW.Y.0010.190211T0000Z-190211T1500Z/
District of Columbia-Prince Georges-Augusta-Rockingham-Shenandoah-
Page-Warren-Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-
Culpeper-Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Northern Fauquier-
Southern Fauquier-Western Highland-Eastern Highland-
Eastern Loudoun-Northern Virginia Blue Ridge-
Central Virginia Blue Ridge-Western Pendleton-Eastern Pendleton-
302 AM EST Sun Feb 10 2019

...WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM THIS EVENING TO
10 AM EST MONDAY...

* WHAT...Snow, sleet and freezing rain expected. Total snow
  accumulations of up to one inch and ice accumulations of less
  than a tenth of an inch expected.

* WHERE...The District of Columbia along with portions of central
  Maryland, central, northern and western Virginia and eastern
  West Virginia.

* WHEN...From 7 PM this evening to 10 AM EST Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions. The
  hazardous conditions will impact the Monday morning commute.

---

 

[Deck Pic]

30/11

I fully accept that I live in UHI hell, but sometimes it is beyond funny.

[North Balti Zen]

1 minute ago, Deck Pic said:

30/11

I fully accept that I live in UHI hell, but sometimes it is beyond funny.

That is insane. I am in 21/11 in my part of Balt city and we are usually running warm compared to surrounds.

[ravensrule]

5 minutes ago, Deck Pic said:

30/11

I fully accept that I live in UHI hell, but sometimes it is beyond funny.

That’s insane. I’m 17/10 right now. 

[showmethesnow]

18 minutes ago, Deck Pic said:

30/11

I fully accept that I live in UHI hell, but sometimes it is beyond funny.

Just realized you are now in DC. Weren't you originally from N Carroll/Westminster county?

[showmethesnow]

Overnight GFS FV3 was more agressive with the snow/ice north of DC especially into NE MD where they get pummeled.

[MD Snow]

Nams and rgem are coming in with less snow/mix for Baltimore south and southwest.

The cause? temps on the nam were running slightly higher. Not much but a degree of 2 will make all the difference in the world. 

[MountainGeek]

13 minutes ago, MD Snow said:

Nams and rgem are coming in with less snow/mix for Baltimore south and southwest.

The cause? temps on the nam were running slightly higher. Not much but a degree of 2 will make all the difference in the world. 

Interesting -- we're going to bust low out here, forecast was supposed to drop to 17 but it's 15 right now.

NAM is wrong already from onset, it's showing temps 4-5 degrees warmer than it is right now. Not sure how much that is going to help later on, but certainly not a bad sign. 

[arlwx]

The latest from LWX:

Warm advection precip should start breaking out across the
region from west to east this evening as the first of several
disturbances moves across the region along a developing
stationary front. A warm nose is depicted in guidance, but its
strength varies, along with the intensity/degree of low level
cold lingering. Given dry air in place, feel it likely most
places see some snow and sleet at the onset, with snow likely to
linger much if not most of the night and morning on Monday in
northern MD. Thus, have highest accumulations generally along
the I-70 corridor, with lower amounts elsewhere. However, the
greater risk of freezing rain further south has caused us to
issued an advisory for most of the CWA. If heavier precip
overwhelms the relatively weak warm nose, greater amounts of
snow are possible, while if precip turns out lighter, it could
be mostly ice/rain instead of snow/sleet. Lows tonight should
settle near or below freezing in most areas thanks to
evaporation from precip falling into the dry air.

On Monday, the first wave pushes east and there may be a lull in
precip, most likely later in the morning into the mid afternoon.
Guidance allows surface temps to warm up during this time, as
well. Thus, cut advisory at 10 AM for now, though its certainly
possible it may need to be extended later for parts of the
region. Temps likely stay in the 30s in most of the CWA, and
across interior locations, it likely struggles to rise above
freezing.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
A second surge of warm advection will develop late Monday and
continue into Tuesday morning. At the same time, strengthening
high pressure over southern Canada may intensify the cold air
damming down the east side of the Appalachians, and temperatures
at low levels may actually fall even as warm advection
intensifies aloft. Thus, some areas which rise above freezing
during the day Monday may drop back below freezing Monday night
before a final rise above freezing Tuesday. This period will
likely see the end of snow in northern Maryland, along with the
greatest risk of significant ice accumulations. Before the snow
ends, however, several more inches are possible in northern MD,
and its not out of the question someone ends up with 6 inches or
more. In addition, the ice risk also brings the potential for a
quarter inch or more of ice, most likely in western MD, but
potentially in locations further east and south as well. Bottom
line is that while we technically have no headlines up for
Monday night, we will certainly need winter weather advisories,
and it may end up being a warning level event. Confidence on
this is not yet high, though, so have left this in the HWO for
now.

Low pressure passing to the northwest should allow just enough
warm air to push north to bring most places to plain rain later
Tuesday. Precip may briefly change back to snow on the back end
as the cold front crosses the region, but confidence on this is
very low.

[MD Snow]

12 minutes ago, MountainGeek said:

Interesting -- we're going to bust low out here, forecast was supposed to drop to 17 but it's 15 right now.

NAM is wrong already from onset, it's showing temps 4-5 degrees warmer than it is right now. Not sure how much that is going to help later on, but certainly not a bad sign. 

Temps during this system will be rate dependent. Get a good slug of moisture in here at onset tonight and we wet bulb below freezing fast. Especially south of b-more. That will play a roll in how high we get on Monday as well. 

[MD Snow]

Gfs finally gets a good slug of moisture in tonight after being stingy about it up until now. Not much frozen south of Baltimore but it’s got a bias for not picking up cad, right? 

[CAPE]

8 minutes ago, MD Snow said:

Gfs finally gets a good slug of moisture in tonight after being stingy about it up until now. Not much frozen south of Baltimore but it’s got a bias for not picking up cad, right? 

I was just looking at the Euro. Problem tonight is the first wave looks like it may only produce light precip for most areas and at the same time a warm nose is moving in aloft from the SW. It would be easily overcome and snow with some good lift. Euro seems to focus the best combo of qpf and cold (850 temps) tonight in the N and NE part of the area, and esp N DE into NJ. Beyond that when the better moisture arrives it looks like a tight N-S gradient sets up from liquid to freezing/frozen to all snow. For a time there could be big differences from just south of Baltimore, to the north side of town. Ultimately the big winners in this set up will be the very N part of MD and points north. PSU and losetoa6 will probably see 5-6" of snow/sleet and some ice before ending as rain.

[showmethesnow]

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

I was just looking at the Euro. Problem tonight is the first wave looks like it may only produce light precip for most areas and at the same time a warm nose is moving in aloft from the SW. It would be easily overcome and snow with some good lift. Euro seems to focus the best combo of qpf and cold (850 temps) tonight in the N and NE part of the area, and esp N DE into NJ. Beyond that when the better moisture arrives it looks like a tight N-S gradient sets up from liquid to freezing/frozen to all snow. For a time there could be big differences from just south of Baltimore, to the north side of town. Ultimately the big winners in this set up will be the very N part of MD and points north. PSU and losetoa6 will probably see 5-6" of snow/sleet and some ice before ending as rain.

Haven't looked at the Euro yet but have been glancing over the American models with their soundings. Am thinking the Baltimore latitude is probably a good dividing point from some snow to appreciable snows myself.

[CAPE]

Just now, showmethesnow said:

Haven't looked at the Euro yet but have been glancing over the American models with their soundings. Am thinking the Baltimore latitude is probably a good dividing point from some snow to appreciable snows myself.

Yeah that is pretty much where the Euro has it. I don't trust the GFS in these set ups, or the NAMs over the Euro even at this range. NAM is in the process of getting to where the Euro is I think. It has been too cold with too much frozen too far south.

[showmethesnow]

1 minute ago, C.A.P.E. said:

Yeah that is pretty much where the Euro has it. I don't trust the GFS in these set ups, or the NAMs over the Euro even at this range. NAM is in the process of getting to where the Euro is I think. It has been too cold with too much frozen too far south.

When comparing the GFS to the 3K the GFS is losing the CAD quicker. Seeing a quicker shifting of low level winds (surface to 925mb) to an E/SE trajectory which is warming the surface quicker. Don't buy it. The NAM is the one to put your money on with it's higher resolution and the GFS' known bias of eroding CAD prematurely. And looking at the 3k NAM 00Z vs. 06z I am not so sure we actually did see what you would call a general warming overall. Maybe, maybe not. Think what we are seeing is more so a difference in timing with the better rates. Where we should probably be looking at is how well it is holding onto CAD and besides some noise it was pretty consistent run over run.

[CAPE]

6 minutes ago, showmethesnow said:

When comparing the GFS to the 3K the GFS is losing the CAD quicker. Seeing a quicker shifting of low level winds (surface to 925mb) to an E/SE trajectory which is warming the surface quicker. Don't buy it. The NAM is the one to put your money on with it's higher resolution and the GFS' known bias of eroding CAD prematurely. And looking at the 3k NAM 00Z vs. 06z I am not so sure we actually did see what you would call a general warming overall. Maybe, maybe not. Think what we are seeing is more so a difference in timing with the better rates. Where we should probably be looking at is how well it is holding onto CAD and besides some noise it was pretty consistent run over run.

Agree on the GFS. The 3km NAM is probably more correct with the low level cold. And yes the rates are going to be a big factor, but the way this usually works out is the best precip will align with the areas that have coldest column, so places further south that could get a good thump before the inevitable low level warming will get screwed lol. Might not work out that way though, especially if the initial shot tonight into tomorrow AM is more robust.

[showmethesnow]

@C.A.P.E.Right now I am thinking there is good potential for a decent sleet/icing event around Balt and especially in its colder western suburbs through the whole period. Just north I would not be surprised if the 10-1 snowfall maps are much closer to reality, especially around the PA line, then the +snow depth maps which I am not really keen on. Think DC scores an inch or two snowboarded. But looking at everything in general there is a high boom/bust potential. We are talking a razors edge here with the temps (mid-levels and surface) where better/weaker rates could mean a world of difference. This doesn't even factor in the air mass being colder/warmer then projected leading into the event. 1 degree here or there probably shifts everything fairly significantly north or south. Shave a degree off the warm nose at midlevels and we see more snow. Shave a degree off the surface and we see more ice. This event pretty much has, 'We won't know what we have until we get it', written all over it. 

[CAPE]

2 minutes ago, showmethesnow said:

@C.A.P.E.Right now I am thinking there is good potential for a decent sleet/icing event around Balt and especially in its colder western suburbs through the whole period. Just north I would not be surprised if the 10-1 snowfall maps are much closer to reality, especially around the PA line, then the +snow depth maps which I am not really keen on. Think DC scores an inch or two snowboarded. But looking at everything in general there is a high boom/bust potential. We are talking a razors edge here with the temps (mid-levels and surface) where better/weaker rates could mean a world of difference. This doesn't even factor in the air mass being colder/warmer then projected leading into the event. 1 degree here or there probably shifts everything fairly significantly north or south. Shave a degree off the warm nose at midlevels and we see more snow. Shave a degree off the surface and we see more ice. This event pretty much has, 'We won't know what we have until we get it', written all over it. 

I agree with your assessment. It could surprise on the southern fringe, or be a total non event. I lean towards the latter because I have seen it happen over and over in these setups. The wildcard and  the part that has my interest, is what happens tonight with the lead area of lift. I am nearly 100% sure anything that happens from tomorrow afternoon forward will result in nothing appreciable on the ground here. Places just north of the City could have a prolonged period of frozen/freezing precip. North of that will probably be frozen for the majority of the event.

[showmethesnow]

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

Agree on the GFS. The 3km NAM is probably more correct with the low level cold. And yes the rates are going to be a big factor, but the way this usually works out is the best precip will align with the areas that have coldest column, so places further south that could get a good thump before the inevitable low level warming will get screwed lol. Might not work out that way though, especially if the initial shot tonight into tomorrow AM is more robust.

Have hit on this first impulse several times over the last few days. It will pretty much show us where the boundary is set up. Those that see snow then will more then likely see snow afterwards as well. It also throws a possibly wild card into the equation as well. Not that I expect it but if we even see some marginal strengthening as that feature runs through our region to off the coast that will tend to drag the boundary a touch farther south. To add another possibly wildcard it looks as if there is another impulse following it that is somewhat hard to separate from the WAA precip moving in. As with the first impulse if we see any strengthening of that feature through our region we could see a little southward shift of the boundary as well. Honestly, this is when tracking is at its most enjoyable. When you have such a marginal setup where just small differences can mean a world of difference in regards to ground truth.

[CAPE]

22 minutes ago, showmethesnow said:

Have hit on this first impulse several times over the last few days. It will pretty much show us where the boundary is set up. Those that see snow then will more then likely see snow afterwards as well. It also throws a possibly wild card into the equation as well. Not that I expect it but if we even see some marginal strengthening as that feature runs through our region to off the coast that will tend to drag the boundary a touch farther south. To add another possibly wildcard it looks as if there is another impulse following it that is somewhat hard to separate from the WAA precip moving in. As with the first impulse if we see any strengthening of that feature through our region we could see a little southward shift of the boundary as well. Honestly, this is when tracking is at its most enjoyable. When you have such a marginal setup where just small differences can mean a world of difference in regards to ground truth.

The 0z Euro shifted the southern fringe of frozen a bit north of previous runs, but I kind of buy it's depiction. Pretty tight gradient. Verbatim the northern burbs of DC east to Dover would see a couple inches of snow/sleet, and beyond that maybe a period of zr. Not much south of there. Just north of that area through Baltimore City has the biggest boom-bust potential IMO. The north part of the city could see several inches of snow and some ice, while BWI would see much less and go over to plain rain much quicker. Ofc this zone could end up further south. Or north.

[aldie 22]

14 hours ago, leesburg 04 said:

All I cared about today was that the models began to recognize the cold air strength. I'd imagine 0z will be better but my make or break for anything beyond conversational is 12z tomorrow. My bar right now is 2" of snow a fair amount of freezy rain at 31 and a little bit of 34 and rain.

I'm gonna stick with this call although the GFS is insistent I stay all rain with zero frozen. 0z nam was the best run for my house 6z not as sexy. Stat padder on the way hopefully.

[PDIII]

I remember a day back in the 90s where we had a similar set up to this.  It was supposed to be a brief period of snow and then a wash out.  My dad and I decided to take the dog for a walk in middle River when it began to snow. By the time we got done there was 3 inches on the ground. It never changed over. I think we got like 5 inches and some sleet. 

Maybe we get lucky. It happens. I am in Baltimore so I can dream...

[CAPE]

1 minute ago, leesburg 04 said:

I'm gonna stick with this call although the GFS is insistent I stay all rain with zero frozen. 0z nam was the best run for my house 6z not as sexy. Stat padder on the way hopefully.

I am hoping for an inch to get me to double digits for the winter. Not exactly padding stats for me. Not sure what to call it lol. Avoiding total futility?

[aldie 22]

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

I am hoping for an inch to get me to double digits for the winter. Not exactly padding stats for me. Not sure what to call it lol. Avoiding total futility?

Hang in there cat man....the great Easter blizzard of 2019 is on the way