Holston_River_Rambler

6z continues its tick south:

6z AIFS ha a pretty good look:

Euro AIFS is running, let's see what it does.

GFS automatically gets a processing upgrade when it shows 30" + of snow in any given Tennessee location. In all seriousness though.........

WPC extended Disco: Model guidance is in pretty good agreement on the upper level pattern through the period, especially over the central and eastern U.S. under the broad upper trough. All model guidance shows Arctic air making it down to the Gulf and East Coasts, which will clash with southern stream energy to produce a potentially high impact winter storm across the southern tier. There are some southern stream differences among the models that may affect sensible weather. The 06Z and 12Z GFS solutions were the only deterministic solutions still hanging on to a slower upper low lingering near Baja California into next week, while other guidance (including AI) has trended much more progressive with this feature. For this reason, the WPC forecast favored a faster solution with very limited influence from the GFS. A faster solution allows for increased moisture across the south-central U.S. ahead of the upper low with a broader precipitation footprint. There is still a significant amount of uncertainty in the QPF forecast this weekend. Models have been trending northwards with the heavy precipitation axis, which is in line with what the AI guidance has been showing, so adjustments were made to the NBM to reflect these trends in the WPC forecast. The WPC forecast used a blend of the ECMWF/GFS/CMC/UKMET early in the period, then increased contributions from ensemble means through the second half of the period while decreasing the influence of the GFS.

New WPC graphic: from this site: https://www.wpc.ncep.noaa.gov/threats/threats.php

Maybe this overpowering northern stream will finally do us a favor and keep heights suppressed in front just enough to ward off as much ice as possible

Euro:

Some pivotal satellite for data collection over the pole will probably get knocked out, lol.

Anything even remotely like a Miller A/B hybrid triggers me lol.

It looks like it ticked south a smidge, but it reeaaaalllly wants to get the big hp out in front of the system and then have the LP attack it.

Neither one have started yet on pivotal:

I guess the AIFS doesn't always start at 15 minutes after the hours 6 and 12.

We need a mountain wave event with the ice too, that'll help.

for posterity (or at least until imgur deletes them) FRAM estimate:

If it keeps to its schedule from last night, Euro AIFS should start up around 12:15.

Every time I try to speculate, lol. disregard the above.

It ran out of color contours lol.

Thank you for asking him about that.

That's where I'm at as far as hope goes now. The 6z AIFS is a much more common winter storm scenario than something like the 1988 Jan southern slider.

Not sure. My (probably wrong) running hypothesis is that it reviews thousands of scenarios at initialization and then runs with a "given a certain set up "X," "Y" will then happen 90% of the time." Lower resolution helps this approach.

Supposedly the Euro AI has been trained on 80 years of ERA 5 data

At least the WPC isn't entirely leaning into the AIFS

AIFS