NH Winter/SH Summer 2020-21 Discussion Thread

Well the much anticipated and well advertised winter storm is
almost upon us. The upper-level low is currently moving across New
Mexico and will gradually continue eastward into central Texas
through the day today. We have been talking about this system for
some time now, so if you have been following along, here are the
main changes...Snowfall totals have increased slightly across the
area. Still thinking the greatest amounts will be along and to
the south of I-20 to a line from near Lufkin, TX to Columbia, LA.
As such, the Winter Storm Watch which was previously in effect has
been upgraded to a Winter Storm Warning, where 2-4 inches of snow
will be possible. Have also added Wood, Upshur and Marion
counties in Texas to the Warning. The remaining parishes and
counties not listed in the Winter Storm Warning have been placed
in Winter Weather Advisory where up to 2 inches of snow
accumulation will be possible. To keep confusion down, both the
Warning and the Advisory will go into effect at 2:00 PM CST today
and continue through 8:00 AM CST Monday.

Short range models, namely the HRRR and NAM, continue to indicate
much higher amounts than the self advertised 2-4 inches we have in
the forecast. Per the previous discussion, true snow to liquid
ratios should be in the 6:1 to 9:1 range instead of the
traditional 10:1 ration many models assume for their associated
snow totals. Our forecast takes into account that surface
temperatures and fairly warm near ground temperatures should make
for inefficient accumulation at first. The higher amounts also
account for the areas where higher snowfall rates could outpace
the melting potential at the surface.