January 24-25: Miracle or Mirage

[SomeguyfromTakomaPark]

The low is basically going just east of north last 2 panels of 6Z euro, LFG!!!!

[mitchnick]

1 minute ago, SomeguyfromTakomaPark said:

Beautiful look, delayed but not denied 

And look where the main trough is! It's going to be snowing for a while after that and ratios will be 2/10/10-like potentially. 

[mappy]

3 minutes ago, winter_warlock said:

It's a beaut Clark!!!  And looks like there is more to come after he 144

Yes but about a tenth less in precip compared to 0z at the end of the run. Probably just noise 

[DDweatherman]

1 minute ago, mitchnick said:

And look where the main trough is! It's going to be snowing for a while after that and ratios will be 2/10/10-like potentially. 

I would pay to see extra frames of that 6z euro fun. Woulda been a HECS for a good bit of this sub given that h5 at the end and what was already OTG thru 144

[Eskimo Joe]

What an awesome batch of overnight runs. To make things even better, I get to be on a panel at IMD today that moderate by Dr. Louis Uccellini. 

[DMAC98]

 

2 minutes ago, Stormchaserchuck1 said:

Did anyone see how far north the 3z SREF is at the end of its run? Even gives us some snow Friday

I was about to mention this because the NAM and RRFS have it as well, almost like an appetizer of sorts.

Looks to be on the Euro as well but it's well S of those two:

[DDweatherman]

Just now, mappy said:

Yes but about a tenth less in precip compared to 0z at the end of the run. Probably just noise 

I think mainly a factor of speed. End result might have been more robust than 0z in totals. Looks awesome up at h5

[Chris78]

6 minutes ago, Weather Will said:

WB 6Z EURO at 1am Monday.

Hey Will. What's the start time? Looks like it's pushed back a little?

[mitchnick]

At 144hrs, the slp is sitting over Nags Head with the 50/50 feeding in cold air and the midwest trough pulling in the Gulf moisture while the slp is sorta stuck. Oh boy!

[Jebman]

NWS in south central TX is hinting at anomalous moisture over our region at the same time that very cold weather is in our area. I may NOT be safe here at all. Anyone in ice accretion regions with this storm please be extremely careful. This storm means serious bisnass.

[SomeguyfromTakomaPark]

1 minute ago, DDweatherman said:

I would pay to see extra frames of that 6z euro fun. Woulda been a HECS for a good bit of this sub given that h5 at the end and what was already OTG thru 144

If it can turn the corner the way it’s showing on 6Z euro this could be a 1 to 2 foot type deal for our subforum. Then we can talk about wind too as the coastal deepens. 

[mitchnick]

If you look at the progression of the Euro, it brings the northern stream trough down with a delay that allows the Baja low to fully ejected and the 2 combined/phased are what we get with that 5H anomaly map I posted.

[DDweatherman]

Just now, mitchnick said:

If you look at the progression of the Euro, it brings the northern stream trough down with a delay that allows the Baja low to fully ejected and the 2 combined are what we get with that 5H anomaly map I posted.

They say good things come to those who wait, slightly slower evolution but the ceiling is very high in that scenario. Would be very PD2 ish in duration and potentially even magnitude. 

[mappy]

8 minutes ago, DDweatherman said:

I think mainly a factor of speed. End result might have been more robust than 0z in totals. Looks awesome up at h5

Oh for sure, just something I noticed up here when comparing runs 

[yoda]

Morning discussion from LWX 

KEY MESSAGE 2...Near-record cold this weekend, along with increasing
potential for a significant winter storm.

As mentioned above, a potent cold front pushes through the
region late Thursday into Friday, followed by a reinforcing
Arctic front late Friday into Saturday. This will lead to
increasingly cold conditions each day from Thursday through the
weekend. Well below average temperatures are forecast,
especially by Sunday. In addition, some upslope snow showers are
possible over the Alleghenies, with low but non-zero chances of
light precipitation further east on Friday. Extremely cold
temperatures are becoming likely Saturday night into next week,
with lows in the single digits and wind chills at or below zero.
Near-record low temperatures are possible during this time.

The upper-level pattern becomes quite active in both the northern
and southern branches of the jet stream heading into this
weekend. Models continue to be in generally good agreement
regarding the development of a low pressure system that tracks
across the southern U.S. A broad area of baroclinic/frontogenetic
forcing will develop along the interaction of an Arctic high to
the north and the deepening low. Ensemble guidance continues to
show an amplified southern stream influence - something we have
seen very little of so far this winter (typical of La Nina).
The surface low may not escape so easily out to sea given the
negative NAO block. The nearby steady source of very cold air
and the amplified southern stream occurring in tandem are what
raise some red flags for significant wintry precipitation
potential this weekend. Ample cold air will remain aloft and at
the surface with strong high pressure to the north and the
strong baroclinic zone to the south. As a result, the 01Z NBM
48-hour probability for at least 6 inches of snow (ending 12Z
Mon Jan 26) are at 40-70pct from NW to SE, and around 20-45pct
for 1 foot of snow from NW to SE. There are some noteworthy
probabilities for even higher amounts, as well, but uncertainty
still remains in regards to the exact track of the system which
could lead to a sharp QPF gradient on the north/northwest side
of the system possibly somewhere over our area.

The latest numerical model guidance continues to show
consistency in regards to the potential of this significant
weekend winter storm across the area. Trends for precipitation
onset time favor Saturday (most likely in the afternoon), with
the heaviest precipitation over the area then occurring through
Sunday afternoon. The last four runs of the ECMWF-AIFS
(deterministic) have shown a southward tick to the axis of
heaviest QPF, likely due in large part to a slower ejection of
shortwave energy out of the Southwest CONUS causing a slightly
flatter and more suppressed storm track. However, the 00Z
operational ECMWF (deterministic) as well as several members of
the EPS and EPS-AIFS (among a handful of members from other
ensembling systems) are also slower and more amplified with a
trailing northern stream wave dipping into the Rockies late in
the weekend; these two slower/deeper waves then phase as they
exit the Rockies and head for the Mississippi Valley. This
scenario results in a broad, flat area of low pressure the gets
caught underneath Arctic high pressure building over the
Northeast CONUS Saturday night, and drifts over the baroclinic
zone draped from the SW Atlantic into the Gulf. This low then
eventually gets absorbed into the deeper phasing trough
approaching from the west. This lifts the low pressure northward
up the coast causing precipitation to linger into Monday. It
should be noted that this is a relatively new shift, not yet
reflected in 01Z NBM progs that were used as a baseline to the
overnight forecast. Have not deviated from NBM and will instead
wait to see if there is some consistency in this outcome, or if
a more suppressed solution becomes more likely.

Depending on where the frontal zone is and where the area of low
pressure tracks, there could be significant wintry precipitation
this weekend over a large part of the South to Mid-Atlantic CONUS.
As noted, the potential is still there for that strong Arctic
high pressure to suppress the low pressure system to our south.
However, the strengthening upstream blocking pattern could
essentially put a floor on how far south the low will track.

Accumulating snow looks almost certain this weekend, with an
increasing likelihood of a warning-level event for much of the
region. But how exactly all of the moving pieces interact will
determine the difference between a moderately impactful snowfall
versus something much more significant.

It is important to monitor this threat closely this week as the
different parts of the system become better sampled by surface and
upper air observations. Stay tuned to weather.gov/lwx/winter
for the latest updates.

 

[Chris78]

Crazy long duration depicted by the Euroai

Starts overnight Saturday into Sunday and doesn't pull out till Early Tuesday.

[mitchnick]

Euro 144hrs 700mb RH map. Southwesterly winds pumping in Gulf moisture all the way back to central Missouri. Yeah...it's gunna' keep snowing for a while after the 144hr panel.

[WxUSAF]

43 minutes ago, mitchnick said:

The snowfall pattern on the Euro last night tells me it'll come further north and even up thru NE should do well. They already did OK on 0z, but I'll bet it gets better for them...and probably us too.

 

21 minutes ago, mitchnick said:

At 144hrs, the slp is sitting over Nags Head with the 50/50 feeding in cold air and the midwest trough pulling in the Gulf moisture while the slp is sorta stuck. Oh boy!

The 0z (and seems like 6z) euro evolution is what I was honking at last night with the 18z run. Long duration events are super rare for a reason, but I’m getting major PD2 type vibes with overrunning and then a coastal. This thing keeps slowing down though so we’re only gaining like 45 minutes on the start time for every hour that passes lol.

[Eskimo Joe]

1 minute ago, mitchnick said:

Euro 144hrs 700mb RH map. Southwesterly winds pumping in Gulf moisture all the way back to central Missouri. Yeah...it's gunna' keep snowing for a while after the 144hr panel.

Oh wow that's classic for a KU event in these parts.

[SnoSki14]

The somewhat slower evolution is a big deal. It allows the high to erode some which will lead to north ticks. 

It also allows more phasing and energy to come in which slows down the storm and increases duration. 

With timing shifting more towards later Sun-Mon that will also increase impacts for all. So you go from a significant/major storm to a KU biggie 

[snowmagnet]

44 minutes ago, Paleocene said:

If this thing holds, Montgomery County school children (like my middle schooler) will be annoyed. They have off Monday for an end of quarter teacher grading day. I think the teachers have to report in though, so they will be happy.

They will probably be off all week. 

[WxUSAF]

Digital red = lots of digital blue

 

[mitchnick]

Eps Snowfall.  North creep continues. 0z on bottom for comparison. 

[Ji]

Digital red = lots of digital blue
 

lol

[Wxdavis5784]

47 minutes ago, Fozz said:

Man I’d love to be in Maryland for this as I’ve waited 10 years for this kind of storm, but it will be tough for me. No need to feel bad though, I’m way up north now and can look forward to single digit highs this weekend 

You all better enjoy this, especially @SnowenOutThere and other young guys who’ve never seen a double digit storm above age 8-10.

Exactly this! I was chatting with my 3 kids over the weekend (Ages 19, 15, 13) Only the oldest can barely remember 2016. I swear these kids think I am lying about the snowstorms of winters past. 

Sorry for the banter. 

[Heisy]

Euro 144hrs 700mb RH map. Southwesterly winds pumping in Gulf moisture all the way back to central Missouri. Yeah...it's gunna' keep snowing for a while after the 144hr panel.

VA in a sweet spot because they’re going to cash in on the WAA goods one way or another it seems. The phase adds risk but also rewards for us. With the phase it’s been slowed a day so still 6+ days out we still have a long way to go


.

[Ji]

Digital red = lots of digital blue
 

I guess the next time the European shows a 4 foot snowstorm at hour 360 we should probably take it seriously

[CAPE]

Latest blend. I think we got us a solid signal across guidance for a major winter storm lol

[LeesburgWx]

3 minutes ago, CAPE said:

Latest blend. I think we got us a solid signal across guidance for a major winter storm lol

Wow, about as good of a blend we can get

[Weather Will]

51 minutes ago, Chris78 said:

Hey Will. What's the start time? Looks like it's pushed back a little?

Fell asleep again.... mid late morning Sunday.