Euro was the first to pick up on the mid level warmth issue on its Monday night run.
The best runs for the storm showed a Saturday night into Sunday storm w a different setup vs the Saturday storm we have now so who knows if that initial scenario would’ve worked.
The surface has been holding pretty steady but the 850 level in particular has been degrading across the past few model cycles to a razors edge at this point
12z 3k NAM looks pretty similar to the 12/16/20 storm with a heavy burst of snow initially across the metro area then watched the CC line move steadily NW; wasn't a bad storm here w around 3 inches and dumped ~6 inches in Frederick https://www.washingtonpost.com/weather/2020/12/17/snow-ice-dc-md-va/
In that storm I went from my parents house in Potomac where we had a plowable snow to Comet Ping Pong in NW where it wasn't much more than a cartopper. 2-17-18 was another one w a sharp gradient from downtown to western suburbs as well.
06z EPS Mean for 1 inch plus is 82% for DCA which is the highest it's been in the past 4 cycles. The 4 inch mean is holding steady the past few cycles around 30% for DCA.
Euro is showing a pronounced warm layer from 850-700 close to the cities in the key 93-96 hr window that the GFS doesn't have. 925 layer is definitely better and 850 is marginally better closer to the cities than the 12z run.
12 z EPS has 31, 69 for 4,1 inch chances for DC
6 z EPS had 35, 65 for 4,1 inch chances for DC
12 z EPS has 92, 55 for 4,1 inch chances for Germantown
6z EPS had 78, 49 for 4,1 inch changes for Germantown
The storm is still 4 days and ~16 model cycles until onset. The final solution isn’t going to be exactly like any of the 12z runs today (for better or worse) so no reason to punt this yet
Worth staying up for the Euro (and having an earthquake) but it reminds me a bit of the 12/16/20 storm where 4-5 days out we looked good for significant snow but the mix line quickly punched into the immediate metro. It was still a pretty fun storm with some high initial rates.