Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EDT Wed Apr 04 2018


Prelim Day 1 QPF Discussion
Valid Apr 04/1200 UTC thru Apr 05/1200 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr


Day 1

...Great Lakes---Northeast---Eastern Seaboard...

The strong closed low moving into the lower Great Lakes Wednesday
morning is expected to progress steadily northeastward across
southeast Ontario into southern QB Wednesday and northeast into
eastern QB Wednesday night/early Thursday.  The well defined comma
head/deformation precipitation band to the north of this closed
low may linger early day 1 over the northeast portion of the L.P.
of MI---but remain mostly north of the border across portions of
southeast Ontario and southern Quebec.  Strong isentropic lift
ahead of this closed low will also support heavy snow potential
over far northern Maine.

In the wake of this system moving northeastward---west northwest
cyclonic flow will persist across all of the Great Lakes day 1. 
This will support scattered snow showers down wind of the lakes
and into upslope of the central Appalachians.

The trailing surface cold front emanating from the above mentioned
low will push quickly eastward Wednesday through the northeast/New
England and off the Eastern Seaboard.  The fast movement of the
front will be a limiting factor for significant precip amounts
with model consensus for .10-.25" amounts from eastern NY
state---central to southern New England---south through the Mid
Atlantic---Southeast and northeast Gulf Coast.


...Pacific Northwest into the northern Rockies...

PW values will be increasing to 1 to 2 standard deviations above
the mean day 1 over the Pacific Northwest into the northern
Rockies as west southwest to southwest onshore flow persists
across these regions.  This will support heavy precipitation
potential from the Washington Cascades west to the Washington
coast range and Olympic Range.  Moderate to isolated heavy precip
totals possible inland through the northern Rockies from northwest
WY into western MT---and northern ID.

Oravec