1/21 - 1/22 Winter Storm Threat

[SnowGoose69]

Can't stop laughing at this.  I guess they never had to use a SNINCR remark before.  Don't believe IAH will have beaten the record for Houston, not sure HOU is considered official site or not

211500 METAR 211453Z COR 01012KT 1/2SM SN FZFG VV007 M03/M04 A3066 RMK        AO2 SLP387 60006 SNOW ON GROUND 3 INCHES TOTAL ACCUMULATED        PRECIP.27 T10281039 53025

[Seminole]

Not an area forecast discussion you see everyday in Florida. The last paragraph had me laughing. 

 

434
FXUS62 KTAE 211124
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
624 AM EST Tue Jan 21 2025

...New AVIATION...

.NEAR TERM...
(Today and tonight)
Issued at 425 AM EST Tue Jan 21 2025

KEY MESSAGES...

-A Winter Storm is expected across the area today and tonight
 with potentially significant snowfall and ice accumulation
 totals.

-Everywhere could see a mixture of precipitation types, although areas
 further north and west are more likely to get snow while areas
 south and east are more likely to get sleet and/or freezing rain.

-There is a low to medium chance (20-40%) of significant and very
 impactful ice accumulation across portions of the FL Big Bend
 and south Central Georgia. If realized, significant impacts to
 trees and power lines are likely.

-Snow amounts of 2 to 4 inches are forecast across portions of
 the FL Panhandle, SE Alabama, and SW Georgia, although there is a
 low to medium chance (20-40%) of accumulations of 6+ inches.

-Regardless of wintry precipitation, extremely cold temperatures
 and dangerous wind chills are expected overnight. Forecast wind
 chills are in the 4 to 17 degree range, which can absolutely be
 dangerous or even deadly to unprotected persons.

A developing low pressure system over the western Gulf of Mexico
is already bringing snow and ice to the Texas and Louisiana coasts
this morning. This system will continue to deepen and move
eastward towards the area today as a shortwave swings across the
base of a large trough positioned over much of the CONUS.
Southwesterly flow aloft will continue to bring increasing
moisture up over a layer of much colder, drier air at the surface.
As precipitation falls into this layer at the surface, it will
gradually cool and moisten over time. Once enough moistening
occurs, wintry precip will begin to reach the surface and
accumulate.

Surface temperatures will matter quite a bit for eventual impacts of
wintry precipitation. The sooner temps fall below freezing, the
sooner accumulation of snow and/or ice will begin. It`s a bit
concerning that we`re already seeing some returns aloft on radar
across the area this morning, indicating that we may be getting a
quicker start to the moistening of the surface layer than previously
expected and therefore a sooner onset of impacts. For that reason,
we have pushed up the Winter Storm Warnings by a couple of hours to
account for this.

Mixed precipitation will be possible everywhere, although areas
roughly from Panama City over to Tifton are most likely to see
mostly snow. Areas further southeast including Apalachicola,
Tallahassee, and Valdosta are more likely to see a mix of rain,
snow, sleet and freezing rain. The Southeast Big Bend (Perry, Cross
City) are more likely to see predominantly rain and freezing rain.
These differences are likely to hinge on razor thin changes in the
surface temps and vertical thermal profile which could very easily
change.

Snow and ice accumulation amounts remain similar to the previous
forecast if not increased just a bit. 2 to 4 inches of snow are
possible across portions of the FL Panhandle, SE Alabama, and SW
Georgia with lower amounts elsewhere. Ice accumulation of .1 to .25
inches are possible across the FL Big Bend and south central GA.
However, there is a low to medium chance (20-40%) that a band (or
bands) of heavier precipitation sets up somewhere over the area.
Models are suggesting frontogenesis may occur along a southwest to
northeast oriented line at the 850 to 700mb level. Wherever that
occurs could really enhance precipitation rates and lead to more
accumulation than expected. If in the snowy area, I would not be
surprised if we saw 6+ inches of snow underneath that band. If it
occurs over the sleet/freezing rain area (particularly the FL Big
Bend and south central GA), significant and impactful ice
accumulation will be possible.

Regardless of winter precipitation, dangerously cold conditions are
expected tonight with low temperatures in the teens to mid 20s and
wind chills ranging from 4 to 17 degrees. However, if there is more
snow/ice accumulation than expected or even earlier in the afternoon
than expected, temperatures may fall faster and end up even colder
than currently forecast.

Please, please take this system seriously. Finish your cold weather
preparations this morning and be prepared to lose power and avoid
travel for a couple of days. Check on your neighbors, family, and
friends; particularly the elderly or other vulnerable
populations. Take care of any animals, pipes, or plants. Playing
in the snow is fun, but make sure you are dressed warmly in loose
fitting layers and change into warm and dry clothing as soon as
you`re done. Monitor for signs of hypothermia and frostbite.

[BooneWX]

Based on saturation above our heads, I just get a feeling that the upstate to Charlotte are in for quite a surprise. 

[CaryWx]

For NC folks west of I95 it all depends on where the FGEN sets up for best precip rates

[wxmoose]

3 minutes ago, SnowGoose69 said:

Can't stop laughing at this.  I guess they never had to use a SNINCR remark before.  Don't believe IAH will have beaten the record for Houston, not sure HOU is considered official site or not

211500 METAR 211453Z COR 01012KT 1/2SM SN FZFG VV007 M03/M04 A3066 RMK        AO2 SLP387 60006 SNOW ON GROUND 3 INCHES TOTAL ACCUMULATED        PRECIP.27 T10281039 53025

Very much a "I don't know what to do with my hands" moment

[GaWx]

14Z HRRR has spot on dewpoints in ATL and GA in general as of 10AM fwiw. But 12Z NAM 10AM dewpoints too high as KATL at 17F vs reality of 8F. It has dewpoints in other parts of GA also too high. Something to keep in mind when considering qpf differences between the two models at least in GA. HRRR may be more realistic.

[Brick Tamland]

[calm_days]

i didn't realize that Mack hadn't posted for a few years now, i just knew that he moved to the midwest!!  hopefully he is doing really well !! 

Anyway this is a good time to honor him as an oldschool snow loving member of the SE forum!!   

@mackerel_sky  

speaking of mackerel, holy mackerel this pattern really stands out in the imagery too!!

[neatlburbwthrguy]

TWC thinking Atlanta metro gets no accumulating snow.  My hopes for a dusting are fading.

[GaWx]

1 minute ago, neatlburbwthrguy said:

TWC thinking Atlanta metro gets no accumulating snow.  My hopes for a dusting are fading.

Even near the airport? What’s changed?

[Silver Meteor]

58 minutes ago, stormwatcherJ said:

I’ve been thinking about this too. Was thinking of driving to the coast to try to see some decent snow. Fortunately wiggle room time is dwindling. I think we get snow at the coast.

 

[neatlburbwthrguy]

Just now, GaWx said:

What’s changed?

The guy on TWC just said he knew all along the snow would be south of ATL.  Pretty bold statement

 

[wake4est]

GFS will raise some eyebrows triangle west

 

 

[Tony Sisk]

2 minutes ago, GaWx said:

What’s changed?

there is not enough moisture.

[WinstonSalemArlington]

Shivering groudhogs

[GaWx]

1 minute ago, Tony Sisk said:

there is not enough moisture.

But we were just talking about the possibility of snow starting in ATL area by late morning.

[NorthHillsWx]

2 minutes ago, WinstonSalemArlington said:

Shivering groudhogs

What a cold winter. We’d forgotten what these were

[ST21]

3 minutes ago, wake4est said:

GFS will raise some eyebrows triangle west

 

 

I’d take that, but does GFS include Virga?

[NorthHillsWx]

12z GFS is WAYYYY west 

[dsaur]

1 hour ago, neatlburbwthrguy said:

Yes, I think so.  Not sure how accurate the KFFC radar is but those returns moving into ATL soon should saturate the atmosphere

Yeah, if something falls it'll be black ice immediately, then it's when can the trucks get the roads treated. Better off the roads than sorry.

[Tony Sisk]

2 minutes ago, GaWx said:

But we were just talking about the possibility of snow starting in ATL area by late morning.

just look at the radar. There is decent "moisture" moving into south Alabama along I-65, and none of that is hitting the ground. This is a very stubborn, cold and dry, artic airmass. 

[Brick Tamland]

12z GFS

[yotaman]

Just now, Brick Tamland said:

12z GFS

8" for my area. I'll take it.

[QC_Halo]

Been in this exact spot in NOLA many times….but not like this!

https://www.earthcam.com/usa/louisiana/neworleans/bourbonstreet/?cam=bourbonstreet

[GaWx]

1 hour ago, neatlburbwthrguy said:

Yes, I think so.  Not sure how accurate the KFFC radar is but those returns moving into ATL soon should saturate the atmosphere

 

3 minutes ago, Tony Sisk said:

just look at the radar. There is decent "moisture" moving into south Alabama along I-65, and none of that is hitting the ground. This is a very stubborn, cold and dry, artic airmass. 

1.5 hours ago it was looking like ATL could have snow before noon. And now you two both think it probably won’t snow at all?

[olafminesaw]

Starting to think there will be an extremely sharp cutoff East of which will get 1"+ and ~30 miles west gets little or nothing. I'm guessing a long or a little east of 85

[NorthHillsWx]

Just now, olafminesaw said:

Starting to think there will be an extremely sharp cutoff East of which will get 1"+ and ~30 miles west gets little or nothing. I'm guessing a long or a little east of 85

That’s a bingo! Agreed. You’ll go from flurries to 1” quick given how little moisture will be needed for 1”

[dsaur]

1 hour ago, RamblinRed said:

In fairness on 2014, since I lived through that - the roads went from drivable to ice rinks in about a 30 minute timespan.

As soon as they iced everything became impassable because of accidents and the inability of cars to drive up icy hills.

Thankfully I worked from home that day but I had teammates who went in to town to work and they got stuck on those roads. 

They brined the highways but it rained first and washed it all away. Then the temp dropped and the frozen precip started. 

There is a great time lapse somewhere of traffic in Atlanta that day. It went from every road being green to every road being red in about 45 minutes.

  I suggest he go out in an automatic without snow tires or chains, find a good untreated hill, with a quarter inch of frozen on it and see how he does, before he disparages Atl drivers, most of whom come from somewhere else, not Ga., lol.

[Brick Tamland]

RAP is coming in like the last NAM.

[Brick Tamland]

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