Fall 2025 WX Discussion Thread

[John1122]

2 hours ago, *Flash* said:

My hometown got crushed by the severe storms today. I didn't take the photo below but was parked within the hail core. Got trees split in the backyard I'll need to clean up tomorrow. Gotta get my kiddos a new trampoline too. 

Glad you guys are okay!

[fountainguy97]

Finally getting into range of high res and the NAM is bringing the goods.  This ULL  could be fun. Perfect timing right after sunset.  And we are COLD COLD. 

[fountainguy97]

This is a very deep batch of moisture (for NW events) and is more than just your typical NW flow.  If the NAM is correct this would bring a few hours of snow across a large portion of the region and not just confined to the NW slopes. 
 

[John1122]

The NAM has it cranking snow over me Monday at 7pm at 23 degrees. May be fun if true.

[Wurbus]

I'm limiting my expectations for this one in Knoxville, but seeing light snow/flurries in the air this early in November is a huge win. If I get a dusting, I'd be happy! Not looking bad at all for plateau, NE TN, & the mountains.

[John1122]

I'm sure it's wonky but the 0z HRRR just walloped me with about 4 inches. It pushes a 2-3 inch streak over deep west Knox county, Loudon County, and into Blount County. The 21z RAP isn't too far off the HRRR except its 2 inch band runs NE of Knox over Morristown.

[John1122]

Looks like most of the hi-res models are showing some convective streaks of snowfall on Monday into Monday night. If that truly happens, someone who gets under one will have a nice surprise. Temps are generally in the 20s for most areas where they happen.  

[Daniel Boone]

1 hour ago, John1122 said:

I'm sure it's wonky but the 0z HRRR just walloped me with about 4 inches. It pushes a 2-3 inch streak over deep west Knox county, Loudon County, and into Blount County. The 21z RAP isn't too far off the HRRR except its 2 inch band runs NE of Knox over Morristown.

There's going to be several area's get more than Forecasted. 

[Holston_River_Rambler]

I haven't started any subscriptions yet, so I don't have access to all the fun charts, but I pulled 0-3km CAPE and lapse rates on the RAP on the COD site from 12z Monday through about the next 20 hours 

CAPE:

 

Low level lapse rates:

Can we praise the sun angle for this one, lol? 

 

 

Euro throws out some 700 mb frontogenesis:

 

Really helps this vort. is rolling through at what peak heating we will have. No matter how you slice it, it looks like we will have moisture, lift, and cooperative temps. Thankfully this isn't October, so we don't have that La Nina kiss of death. 

 

Euro and RGEM take the vort. right over my head in Morgan County. NAMs like TRI, SWVA and Eastern KY.  GFS looks like MRX gets the overhead pass. 

 

[Holston_River_Rambler]

New graphic as of 5am eastern from MRX:

Watches, advisories, and warnings:

 

Some key goosies from teh overnight Disco:

As such, I am highly confident there will be widespread snow showers
across at least the northern half of the CWA, if not the northern
two thirds of the CWA during that time. It`s entirely possible some
locations could pick up an inch of snow or more - one might even say
it`s likely. However, confidence in where exactly that occurs is
very low.

 

Recent ensemble data shows
increasing confidence in a notable snowfall event for the Smokies,
with probabilistic data giving high confidence in snowfall totals
exceeding 8 inches. The evening shift updated the totals to include
an 11" total for Mount LeConte area, and Newfound Gap won`t be too
far behind that I don`t believe. Went ahead and upgraded the Watch
to a Winter Storm Warning because of this. Additionally, there`s
sufficient confidence in snowfall totals exceeding Advisory level
criteria elsewhere in the east TN mountains and the higher terrain
of our Virginia counties, so I added an Advisory to those areas,
grabbing Monroe county on the southern end too. There`s signal in
the higher resolution guidance that shows Sams Gap area along the I-
26 corridor closing in on the 5-6" range; I wouldn`t be surprised if
the High Knob area in Wise county winds up with something similar.
Elsewhere, other areas in the advisory should be covered just
fine with the 1-4" totals.

It`s highly likely that some adjustments or outright
expansion of snowfall totals, areal coverage of these headlines, or
both, will be needed on the day shift today.

[tnweathernut]

On 11/7/2025 at 6:46 PM, fountainguy97 said:

Not to derail the thread but why did it get shut down? Drama? 

That I don’t remember.  I seem to recall one person was in control of everything.  That alone was likely enough to be a big problem, just waiting for a time to present itself.

[Save the itchy algae!]

Sounds like the local office is going to expand advisories in the pm update. We’ll see! Getting my leaves situated by the road hoping the cold front blows them down the street later..


.

[John1122]

Temp has started falling here. It's down 6 degrees in the last 45 minutes. 

[Holston_River_Rambler]

RAP and HRRR give us a radar presentation like a little cyclone tomorrow. I wonder if that will verify? 

[jaxjagman]

My thinking is later on there will be a phoon headed towards China the next couple days,this will pump up the heights from the Yellow Sea into Japan along with the MJO headed into the WP,so that should be height rises towards Mid Nove for a few days,guess the good news right now is the MJO could possibly go into the COD,but anyways what the EPS seems to be showing today is a trough going thru East Asia round the 15th,so we'd probably be seeing a CF right before thanksgiving and back to BN temps at least for a bit..JMO

[John1122]

MRX keeps the higher snow chance tonight for my area but models seem to suggest tomorrow afternoon is the better shot. Either way, they chose to not expand any advisory to my area. 

[Daniel Boone]

16 minutes ago, John1122 said:

MRX keeps the higher snow chance tonight for my area but models seem to suggest tomorrow afternoon is the better shot. Either way, they chose to not expand any advisory to my area. 

Typical MRX. The area's they have in the 1-3" Range should of had an Advisory as it meets Snow Advisory Criteria. Sad. 

[TellicoWx]

43 minutes ago, John1122 said:

MRX keeps the higher snow chance tonight for my area but models seem to suggest tomorrow afternoon is the better shot. Either way, they chose to not expand any advisory to my area. 

Depending on how the overnight runs go, I could see them doing an expansion in the morning. Setup is 2 separate features potentially (tonight's true NW flow, and tomorrow midday thru evening vort pass). Hrrr and 3k differ in exactly how far south into the valley the vort will pass. Add in some daytime instability and would not be surprised to see even the central valley floor over produce in streaks. Even the lower res models are subtly hinting at the potential. 

[John1122]

Temp is down to 39 with a few sprinkles starting.