Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
148 PM EST Sun Mar 04 2018


Prelim Day 1 QPF Discussion
Valid Mar 05/0000 UTC thru Mar 06/0000 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr


Day 1

...Rockies and Central U.S...

Locally terrain enhanced snows will linger over the northern
Rockies into tonight as a dynamic mid-upper level trough and
associated height falls/jet punch works through. System
progression meanwhile spawns plains cyclogenesis with surface
system deepening coincident tomorrow with development of a closed
low aloft over the north central plains and upper midwest.
Moisture feed will deepen with precipitable water values expected
to rise in excess of 2.5 standard deviations above normal wrapping
on the eastern periphery of the system. Precipitation will
increasingly expand/organize in a region of favorable upper
diffluence mainly along/ahead of a lead frontal system/boundaries
over the MS valley and back into the snowy comma head over the
colder and windy Dakotas and Upper Midwest. Please see local WFO
and WPC winter weather desk products for more information on this
disrupting March storm that could produce local blizzard
conditions. The return flow of moisture farther south near the
surface from the Gulf of Mexico, with a continued connection aloft
from offshore Baja California, will meanwhile generate showers and
thunderstorms across the lower and mid MS valley with some
moderate rainfall potential. Overall, the WPC day1 qpf for this
period was primarily derived from WPC continuity as locally
adjusted to latest trends from reasonably compatable 12 UTC GFS
and a ARW/NNMB meso-model and NBM guidance.

...Northeast...

Guidance generally now agrees that compact closed trough energy
will slide southeastward across New England underneath higher
latitude blocky flow today. The unsettling flow could be dynamic
enough to squeeze out a swath of light-modest snows today/tonight
with a potential focus over southeast New England, but moisture
will be quite limited.    

Schichtel