Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS04 KWBC 181819

Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
219 PM EDT Wed Apr 18 2018

Prelim Day 1 QPF Discussion
Valid Apr 19/0000 UTC thru Apr 20/0000 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr

Day 1

...Lower Great Lakes---central Appalachians--northern Mid Atlantic
into southern New England...

The strong compact closed low producing late season heavy snow
Wednesday afternoon over the Upper MS Valley region will be moving
quickly eastward tonight to the south of the lower Great Lakes and
across the central Appalachians and Mid Atlantic Thursday.  There
is fairly good model agreement on a narrow axis of moderate precip
totals in the .25-.50" range in the region comprising a well
defined comma head/deformation precip band to the north of the
closed low center and an isentropic lift maxima to the northeast
of the associated surface wave.  This will support the .25-.50"
precip band from portions of the lower Great Lakes---across the
northern Mid Atlantic/southern tier of NY state into southern New
England.  Late season accumulating snows possible on the northern
edge of this precip shield from northeast OH into northern
PA---southern tier of  NY state.  See the latest QPFHSD for
additional winter weather information across this region.

...Mid Atlantic---southeast---southern Appalachians---gulf coast
and Lower MS Valley...

The trailing frontal boundary from the surface wave pushing
eastward from the lower Great Lakes---northern Mid Atlantic into
southern New England is not expected to have much in the way of
precipitation along and ahead of it.  The inflow off the Gulf of
Mexico ahead of this front is not expected to have a significant
southerly component---limiting the potential for above average pw
values being entrained ahead of this front.  This along with the
fast movement of the front and generally poor dynamics will keep
any precip on the light side from the Mid Atlantic---into the
southeast---southern Appalachians---gulf coast into the Lower MS

...Oregon---California into the Great Basin...

The next in the recent series of strong closed low to affect the
western U.S. will be pushing inland into northern to central
California tonight and into the southern Great Basin Thursday.  PW
values are not expected to be anomalous---mostly at or below
seasonal norms. This will limit precipitation potential with this
system---with mostly light to moderate totals expected from
Oregon----California and into the Great Basin.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.