Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
252 AM EDT Thu May 10 2018


Prelim Day 1 QPF Discussion
Valid May 10/1200 UTC thru May 11/1200 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr


Day 1...

...Central Plains to the Upper Mississippi Valley...

As deepening moisture interacts with a shortwave trough emerging
from the northern Rockies, there remains a good model signal for
moderate to locally heavy, and potentially excessive rains, from
the high plains of eastern Wyoming and western Nebraska to
southern Minnesota and northern Iowa Thu night into Fri morning. 

As a mid-upper level shortwave trough moves across the northern
Rockies Thu afternoon, Overall models are in good agreement
indicating surface low development over eastern Colorado   This
will result in deepening moisture across eastern Wyoming and
western Nebraska as increasing southeasterly flow north of the low
draws moisture into an east-west oriented boundary stretched
across the region.  This moisture, along with afternoon heating
and the larger scale lift supported by the approaching shortwave,
is expected to spur convection developing from southeastern
Wyoming across western and central Nebraska Thu evening. 

As the low level jet continues to amplify, focus for convection
and the heavy rain potential is expected to shift further north
during the overnight hours to along the 850mb boundary extending
from the eastern Nebraska-South Dakota border to the
Minnesota-Iowa border.  Sustained southerly low level inflow into
the western flank of the boundary may support redeveloping
convection as it interacts with the approaching shortwave and
right-entrance region upper jet dynamics -- raising the threat for
heavy amounts across the region through the end of the period.

Given the overall good agreement with respect to the larger scale
features, WPC QPF was weighted largely toward the HREF mean.

Pereira