January 24-25: Miracle or Mirage

[baltosquid]

1 minute ago, mitchnick said:

I posted earlier the 6z GGEM was colder at 84hrs vs 90hrs at 0z, so they're consistent. 

Also RGEM definitely slower with the Baja piece. Way too much heartburn over 06z. It was a much more skeptical set of runs concerning a phase. Also watch the flow out front… it seems like it wants to angle down, more northwesterly than southwesterly across guidance. That kind of suppressive look will also be super helpful to keep this thing pinned.

[Scraff]

4 minutes ago, H2O said:

We are now into the debate over watches and what kind and timing and who gets a WSW vs a WWA?  #toosoon

My question. When will they issue the flood watch for Georgetown? 

[Stormchaserchuck1]

11 minutes ago, H2O said:

We are now into the debate over watches and what kind and timing and who gets a WSW vs a WWA?  #toosoon

They may eventually issue some blizzard warnings if that High pressure stays so strong to the north. 

[clskinsfan]

NAM running. 

[stormtracker]

5 minutes ago, H2O said:

We are now into the debate over watches and what kind and timing and who gets a WSW vs a WWA?  #toosoon

Damn. I thought the WSW debates would have waited to 18z at least.   Guess we starting Christmas decorations right after the 4th of July here too. 

[baltosquid]

4 minutes ago, WxUSAF said:

FWIW, we’re in that range where EuroAI has been deadly and I think pretty much our entire sub would sign up for its 6z in a hot minute. 

I do think with the past weekend small event the AIs (both of them) tended to overdo the NW trend a bit before backing off to a middle ground. So if that is something they repeat, would be excellent. Obviously on a much different scale…

[Stormchaserchuck1]

9z SREF

[TSSN+]

1 minute ago, Stormchaserchuck1 said:

9z SREF

Ah yes I love the ncep maps from the civil war era 

[T. August]

Like others are saying, if we can lock in an incredible front-end thump of 10-15” region-wide with 2”/hr rates, I don’t really care if it mixes after the fact. 

[H2O]

7 minutes ago, Scraff said:

My question. When will they issue the flood watch for Georgetown? 

They should raise the flood gates in preparation

5 minutes ago, stormtracker said:

Damn. I thought the WSW debates would have waited to 18z at least.   Guess we starting Christmas decorations right after the 4th of July here too. 

Don't need to put them up if you never take them down.  

 

28.6/14 and full sun  

 

Where's the obs thread?

[Nomz]

Good morning. Kept my forecast for DC at 4-8+ for now. Probably gonna revise up to 6-10 if the 12z suite doesn’t move much.

[Quasievil]

This is what model watching is all about folks. We can't expect clean model runs from now until Saturday. In any event, remember this - no one really cares if you switch to sleet if you're staring at a foot of snow. These robust systems tend to do that anyway given their dynamic nature. We can start to panic a bit if the LOW ends up in PA.

[BristowWx]

3 minutes ago, Nomz said:

Good morning. Kept my forecast for DC at 4-8+ for now. Probably gonna revise up to 6-10 if the 12z suite doesn’t move much.

I'll admit you lost me as you've given us quite a bit to digest there.  Gonna need a minute.  

[IUsedToHateCold]

I feel like the recon data ingest is the last point where this can fail. If we get good modeling on the energy coming on shore and we're still good, then it's all systems go. 

I feel like the solutions where we flip to sleet in the east/southeast are probably right based upon past storms. I'd say the majority of major storms since I moved to the area in 2011 have been that way. If that doesn't happen we're probably ending up with less overall QPF as we end up with a weaker coastal or none at all. So it's like 10-14 inches or 14-20 inches plus sleet. I'll take the sleet any day. It's a good chance to go out and shovel since it doesn't accumulate fast and you can put salt down to melt it easily.

[Weather Will]

Going to put my heat mats out today.  Hopefully won't jinx things...

[Wonderdog]

15 hours ago, BristowWx said:

There you are…Jesus I was getting nervous 

Don't get nervous. We're still days away.

[baltosquid]

FWIW FV3 run seems to hang the Baja low back a tad thru hr30, bit more separation from the NS… yes this is a very premature read!

[87storms]

Growing up in Silver Spring, sleet was usually the price to be paid for a juiced up EC storm. Less worried about that scenario in Frederick (unless this system cuts like Feb 94) and looks like everyone closer to the fall line gets an overrunning thump anyway.
 

We’re in the Euro’s money range. Today’s runs will be important.

[Scraff]

1 minute ago, Weather Will said:

Going to put my heat mats out today.  Hopefully won't jinx things...

WTF? Are you trying to make it sleet!? 

 

[midatlanticweather]

12 minutes ago, T. August said:

Like others are saying, if we can lock in an incredible front-end thump of 10-15” region-wide with 2”/hr rates, I don’t really care if it mixes after the fact. 

No... pure powder is the only thing for me.. I do care... I would care less.. but still care

[EstorilM]

32 minutes ago, NorthArlington101 said:

Aldie basically said it but LWX pushed their updates to the maps…

That's pretty impressive considering how conservative they typically are.  The big storm that went south last year didn't have this type of confidence (at any point.) 

I guess we've been burned so many times that I'm not sure how to handle what's happening. There's a unicorn appearing before my very eyes and I'm not sure how to interpret it lol. 

Sterling NWS / LWX AFD - https://forecast.weather.gov/product.php?site=LWX&issuedby=LWX&product=AFD&format=CI&version=1&glossary=1&highlight=off

In a multi-
day sense, global ensemble probabilities remain very high for
seeing 6+ inches of snow. This comes with the presumed snow-
to-liquid ratio of 10:1 which this system will not be given the
Arctic nature of the air mass. Ratios could be considerably
higher yielding a fluffier snow. With the parent features still
across the more barren high latitudes, models may take another
day or two to resolve such features with better precision (note:
recon flights are expected to take place near the Southwest
CONUS later today - that`s where models have been most sensitive
to changes, so hopefully this additional data will help hone in
on details). The details will be important in determining any
precipitation type transitions. However, given the very cold air
locked in at and near the surface with strong Arctic high
pressure anchored firmly to our north, plain rain is highly
unlikely anywhere in the region. It will therefore come down to
snow versus ice, both of which could be significant and highly
impactful across a widespread area.

.
 

KEY MESSAGE 2...Frigid temperatures are looking like a virtual certainty
this weekend into early next week.

As mentioned in the winter storm section, Arctic high pressure takes
charge over the weekend which yields frigid temperatures across the
area. On Saturday, forecast 850-mb temperatures range from -15 to
as low as -20C which even dry adiabatic mixing would keep
surface temperatures below freezing. However, given the time of
year and the fact 1000-850 mb winds are northerly, mixing
largely tops out around 900 mb. With that said, Saturday`s high
temperatures should struggle to escape the teens in most spots,
with a few low 20s possible across far southern Maryland. Along
the Allegheny Front, single digits are likely all that can be
mustered. As snow comes in Saturday night, this will fall amidst
temperatures in the single digits to lower teens.

I'm still not used to the "key message" numbering thing for AFDs vs. the normal 1 day, 3 day, extended, etc. 

[87storms]

29 minutes ago, csnavywx said:

RRFS-A coming into range and has basically the same evolution. Slower/less perfect interaction between 00 and 06Z and a bit stronger with the eastern lobe of the high. Interested to see if this becomes a trend given that both trailing N/S waves have yet to become their own entities.

I can’t be the only that hasn’t loved the look at h5. I’m used to seeing a closed low south of us for the biggies. But science Is science and a snowstorm is a snowstorm. Just makes me pause a bit until all the Euro and GFS really start to converge.

[CAPE]

[paulythegun]

21 minutes ago, Stormchaserchuck1 said:

9z SREF

This is a picture perfect overrunning precip profile. Would love to be tickled by some of that dark blue on the next run.

The red on the Greenland coast is "rage"

[BristowWx]

7 minutes ago, Wonderdog said:

Don't get nervous. We're still days away.

Few days.  It’s hard to wrap our heads around things coming together.  Doesn’t happen that often.  The obs thread will be poppin’ soon

[clskinsfan]

NAM slow as hell this morning. Hopefully not a sign of the rest of the model runs.

[T. August]

NAM a lil slower/less interaction through 42

[Buddy1987]

5 minutes ago, clskinsfan said:

NAM slow as hell this morning. Hopefully not a sign of the rest of the model runs.

@36 the large lobe of energy north of MN/WI seems to be having an effect here. More pronounced with strength and progression on kinking southwest. Curious how it will relate downstream.

Ok yea.. @42 confluence is pretty pronounced here compared to 6Z. Again I KNOW we are talking Nam but any positive shift is always a good sign to kick off 12z runs.

[yoda]

Since we all have nothing better to look at right now... 12z NAM at 45 h5

 

[adelphi_sky]

5 minutes ago, BristowWx said:

Few days.  It’s hard to wrap our heads around things coming together.  Doesn’t happen that often.  The obs thread will be poppin’ soon

I am excited that the what falls won't melt away in three days. Give me enough to make everything white and then freeze it for a week. My dream winter.