Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
251 PM EDT Thu May 24 2018


Prelim Day 1 QPF Discussion
Valid May 25/0000 UTC thru May 26/0000 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr


Day 1

...Northern California---central to southern Oregon---northwest
Nevada...

Overall very good agreement on the slow east northeast movement of
the developing closed low off the central California coast--with
this system pushing inland Friday into central to northern
California.  Strongly difluent upper flow to the north and
northeast of this closed low will support increasing convection
Friday from northern California---across northwest NV and into
southern to central Oregon.  Much above average pw values in this
strongly upper difluent pattern will support heavy to isolated
excessive rainfall amounts across these areas.  No changes made to
the marginal risk on the Excessive Rainfall Outlook.

...Upper Great Lakes---Upper MS Valley---portions of the Great
Plains...

A fairly large region of scattered convection possible day 1 ahead
of surface cold front expected to move slowly eastward across the
Great Plains.  Continued low confidence in this scattered
convection regime---with a large spread with respect to the
details of potential max qpf areas.  There is some model consensus
for a potential max region from central to eastern KS---northeast
OK into southwest MO and northwest AR.  Another possible max
region is over portions of the Upper MS Valley into the Upper
Lakes in a region of max isentropic lift along and to the
northeast of a northeast moving warm front.  With pw values
remaining above average across these areas---localized areas of
heavy precip possible where convection does maximize.

...Central Gulf coast into the Southeast...

Not a lot of changes expected to the recent pattern across the
Central Gulf coastal region and into the Southeast day 1. PW
values expected to remain 2+ standard deviations above the mean
along and to the south of the weakening stationary front draped
from the Lower MS Valley into the Southeast.  A nearly stationary
mid to upper level vort over central Georgia will continue to act
as a focus for heavy precip totals in the vicinity of this feature
over large portions of Georgia.  Somewhat higher confidence with
heavy precip totals near this feature---with lower confidence
elsewhere across the Central Gulf coast and Southeast.  There will
continue to be the potential for slow movement of cells and heavy
to locally excessive rainfall amounts across these areas day 1. 

...Keys into South Florida...


Precipitation should be increasing day 1 across the Keys and South
Florida as the developing area of low pressure in the vicinity of
the Yucatan Peninsula begins to push northward.  With tropical
moisture being advected northward on the eastern side of this
low---the heavy precip threat will increase day 1---continuing
into the day 2 and 3 time period.  See the latest NHC outlooks or
potential future advisories for additional information on this
system.

...Northern Maine...

Height falls dropping southeast across central QB will support the
potential for several waves of precip to streak in a west
northwest to east southeasterly direction across northern Maine
this period.  The potential for several waves of precip will
support moderate to locally heavy totals---with the latest models
showing fairly good agreement here.

Oravec