Jan. 19-20th, 2024 | Winter Storm Speculation

[Poco]

Fwiw 

12z eps mean snowfall  10:1

[Undertakerson2.0]

FWIW - CIPS 

[Wtkidz]

LWX. About this storm

 

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Arctic high pressure and below normal temperatures will dominate the
weather pattern during the second half of the week. A reinforcing
shot of Arctic air is likely for the upcoming weekend.

Dry conditions are currently anticipated Wednesday through Thursday
thanks to high pressure pushing very dry air overhead, suppressing
any precipitation to our south. By Thursday night, a trough will
approach from the Midwest. Ridging over the western CONUS and a
downstream upper-level low near the Canadian Maritimes results in a
blocky pattern, where low pressure may develop near the East Coast.
Given cold air in place, precipitation would most likely be of a
wintry variety. Trends will need to be closely monitored through the
week for this system.

In the wake of the trough/low, blustery and very cold conditions are
likely Saturday into Sunday.

 

[Bucikaroo]

I really think who ever is doing our forecast is on something good,

[Penn State]

[Poco]

18z gfs 

 

18z nam 

 

gfs really dampens that energy while Nam has it holding up a bit longer.  Obviously some native resolution and time constraints comes into play here.  However that is the piece that rotates down around the ULL.  How strong it drops in can determine the depth of the eventual ULL.   So although the long and medium range models see that energy right now it is quite possible they aren’t getting parcel strength exactly right.   I remember the one run the gfs had where the energy dropping down remained strong and it was the best run for storm lovers.   Another thing to look at is the Nam has an ULL already created at hr84 whereas the gfs hasn’t split yet, not until hr 114, again native resolution aside it’s a bit different. 
 

So for me the two things I’d watch for here is the strength of that parcel and the positioning of the eventual ULL which is getting pulled by our midweek storm one way as the north western energy parcel pulls it the down in the other.  Where that ULL is positioned and how strong the vortmax is at the bottom will determine everything. 
 

I like the concept and idea of a strong compact snow band on this one.  If that vort can scream down and turn the ULL strong dynamics would be at play at that point. 
 

remains very interesting 

Edited January 15 by Poco

[Poco]

Gefs at 18z was like a 5050 split with about half members running coast and half on the other side of the mean. 

Kinda funky, but clustering maps would be like 50/50. It’s that kind of setup, not much middle ground as of right now 

Edited January 15 by Poco

[Rickrd]

0z Euro at this time is weaker then 12z. 

Edited January 15 by Rickrd

[Wtkidz]

LWX  AFD

 

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
High pressure will move east on Thursday to allow for a front to
setup across the region Thursday afternoon through Thursday night.
Low pressure will form along this front Thursday night as a mid-
level disturbance moves across the Ohio Valley into the mid-Atlantic
region. There is a chance for some light snow late Thursday
into Thursday night along the front and accompanying the low
pressure system. Light snow is likely in the mountains of the
Alleghenies Thursday night. Temperatures will be 5 to 10 degrees
below average for mid-January on Thursday.

During the period of Friday and Friday night, the low pressure
system and its associated mid-level energy will transverse to the
East Coast of the U.S. Here is where the low pressure will rapidly
intensify offshore. It is within this period of Friday and Friday
night, more light snow or snow showers are possible over a large
part of our region. It is too early to know how much snow will
accumulate and where, but this low will be the next weather maker
once Tuesday morning`s low pressure system exits our region.
Temperatures will once again be below average Friday into Friday
night.

A building ridge of high pressure will evolve Saturday and Sunday as
the low pressure system and its energy exits to the east. Dry
conditions with sunshine expected each day; however, temperatures
will remain quite cold with highs and lows 10 to 15 degrees below
their normal mid-January values.

&&

[Sentinel]

The coast should not sleep on this one. 

[Penn State]

This thing has life.. If things could consolidate a little quicker, would be fun! 

[GregRups]

I like where it is right now. The GFS is still shifting tomorrows storm NW. 

[Penn State]

3 minutes ago, GregRups said:

I like where it is right now. The GFS is still shifting tomorrows storm NW. 

You can see the shift W on the 500mb.. Have to think it’s a good shift. 

[Penn State]

GDPS with the shift W too.. 

[GregRups]

Just now, Penn State said:

GDPS with the shift W too.. 

Big Shift. I dont know how to do GIFs on my Mac but hour 108 looks like a really nice storm. Def moved NW

[Undertakerson2.0]

Meh - I'll wait to Baby-G comes into range (lol) 

[Penn State]

Anyone have the GMAO? Curious if it shows anything prior to the Euro this afternoon. 

[Undertakerson2.0]

5 minutes ago, Penn State said:

Anyone have the GMAO? Curious if it shows anything prior to the Euro this afternoon. 

I looked, it seems like its a relatively modest event with no raging SLP - decent QPF and with ratios probably a bit more than today/tomorrow

So hard to tell for sure given the maps they provide

https://fluid.nccs.nasa.gov/wxmaps//?one_click=1&tau=117&stream=G5FPFC&level=0&region=nam&fcst=20240115T000000&field=precip

[Penn State]

9 minutes ago, Undertakerson2.0 said:

I looked, it seems like its a relatively modest event with no raging SLP - decent QPF and with ratios probably a bit more than today/tomorrow

So hard to tell for sure given the maps they provide

https://fluid.nccs.nasa.gov/wxmaps//?one_click=1&tau=117&stream=G5FPFC&level=0&region=nam&fcst=20240115T000000&field=precip

That description is about dead on.. I still think this is close to being something. 

[Undertakerson2.0]

I  will say, the Ens's look pretty sweet for this one. I still say we get no big-uns until Feb, but these large NADS events will hold over. 

 

[Poco]

End of run Nam comparison 18z to 12z 

12z

 

18z

 

Northwest parcel orientation is more vertical and the northern ull has a more consolidated and further south lobe that is looking to interact  with the pac stream 

these small differences affect the surface reflection on the last frames 

 

do note this is long range Nam so not looking at it as if right or wrong, just noting any small differences run to run 

[Wtkidz]

Maybe a threat . All the rest are green. Minor inconvenience. 

• 

[Wtkidz]

Sterling is monitoring, 

LONG TERM /THURSDAY THROUGH MONDAY/...
High pressure overhead Thursday morning will be pushed eastward
throughout the day as an upper level trough deepens and pivots
towards the area from the west. Upslope snow showers return to the
forecast Thursday morning as westerly winds gust 15 to 20 knots at
higher elevations. There is a slight chance of precipitation in
Maryland and the southern portions of our forecast area Thursday
afternoon with cooler temperatures leading to possible wintry
precipitation. High temperatures on Thursday will top out in the mid
30s to low 40s for most with higher elevations staying in the 20s.

Precipitation chances overspread the area overnight Thursday into
Friday as model guidance indicates an area of low pressure
developing and travelling up the east coast. With high temperatures
forecast in the low to mid 300s for most (teens and 20s at higher
elevations), any precipitation will be snow. We will continue to
monitor this event as it gets closer in time

Edited January 15 by Wtkidz

[Penn State]

RDPS long-range.. looks more organized than than the major global models to me at least.

[StretchCT]

Graph is the only AI model with this remotely close.

The rest all have it either forming way offshore or weak and moving well ots, then bombing out in the Maritimes.

 

Edited January 15 by StretchCT