From DVN:
UPDATE
ISSUED AT 809 PM CST THU JAN 13 2022
18Z GUIDANCE, SPECIFICALLY THE NAM BRINGS MORE SNOW ACCUMULATION
FURTHER EAST. DIVING INTO THE DETAILS OF WHY THIS HAPPENS AND WHAT
WE NEED TO SEE IN 00Z GUIDANCE TO SEE IF THIS IS A FLUKE OR A
TREND FOLLOWS. SNOWFALL ACCUMULATION IN THE 18Z NAM RAMPS UP FROM
21Z TO 03Z AND DROPS CLOSE TO 3/4 TO ONE INCH AN HOUR FOR A FEW
HOURS. THIS IS WHAT INCREASE THE EASTERN SNOW TOTALS. LOOKING TO
FORCING, THE OMEGAS IN THE DGZ PEAK EARLY IN THE NAM, 15 TO 21Z
AND THEN FALL THROUGHOUT THE EVENT. TRUE WE GET COLDER, BUT WE SEE
MORE CLIMO SNOW RATIOS AT THIS TIME. THIS EASTERN EXTENSION OF THE
HIGHER SNOW AMOUNTS DON'T SEEM TO BE TIED WITH THE HEAVIER AXIS
SHIFTING EAST, AS MUCH AS ADDITIONAL SNOW THERE. THE CLIPPER AND
BETTER CVA ARE WEST OF THE AREA, WHERE MODELS HAVE CONSISTENTLY
HAD THE HEAVIEST SNOWFALL. THE NBM HAS TRENDED EAST WITH AN
ADDITIONAL INCH OR SO TO TOTALS, LIKELY FROM THE 18Z GUIDANCE. THE
00Z NAM IS STARTING TO COME IN AND IS BACKING OFF ALL SO SLIGHTLY
FROM THE 18Z WITH EASTERN AMOUNTS. WILL NEED TO KEEP AN EYE ON 00Z
GFS ALONG WITH ENSEMBLE DATA, WHICH CONTINUES TO SUGGEST THE
CURRENT FORECAST IS CORRECT. WHILE THE DIFFERENCES HERE ARE
AMOUNTS, THE IMPACTS ARE LIKELY TO BE UNCHANGED UNLESS WE CAN SEE
1+ INCHES AND HOUR AND DRIER SNOW BLOWING AROUND. WITH WET SNOW TO
START, ONE WOULD THINK THAT THE CURRENT SNOWPACK WOULD BE MORE
STICKY TO THAT THAN DRIER SNOW. 00Z GUIDANCE, ESPECIALLY ENSEMBLES
WILL HELP FINE TUNE FORECAST OVERNIGHT.
THE 00Z HRRR IS IN AND,
WHILE NOT AS AGGRESSIVE AS THE 18Z NAM, DOES HAVE MORE SNOW EAST.
THIS SOLUTION WOULD POINT TOWARDS A POSSIBLE EXTENSION OF THE
WARNING EAST BY ONE COLUMN OF COUNTIES.