Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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

FXUS04 KWBC 171754

Quantitative Precipitation Forecast Discussion
NWS Weather Prediction Center College Park MD
153 PM EDT Sat Mar 17 2018

Prelim Day 1 QPF Discussion
Valid Mar 18/0000 UTC thru Mar 19/0000 UTC
Reference AWIPS Graphics under...Precip Accum - 24hr

Day 1

Southern Appalachians into the southern Mid-Atlantic

The relatively small closed low initially over the upper MS valley
region expected to continue to weaken day 1 as it presses east
southeastward from the upper OH valley into the central
Appalachians and southern Mid Atlantic tonight into early Sunday.
The model consensus is for precipitation ahead of this closed low
to refocus across the southern Appalachians this evening and move
fairly quickly east southeast across the southern Mid Atlantic
tonight.  The quick movement likely to be a detriment to any
widespread heavy totals with model consensus for areal average
moderate to possibly isolated heavy amounts across these areas.

Southern Plains---lower MS Valley---central Gulf coast

Height falls in the southern stream flow expected to push east
northeastward out of northern Mexico into the southern Plains this
evening---eastward toward the lower MS valley by early Sunday.
There is a fairly consistent signal in the hi res guidance for
convection to develop late this afternoon over portions of north
central TX and move fairly quickly downstream.  Despite the
expected fast movement---intense rainfall rates over a short
period will support locally heavy to isolated excessive rainfall
amounts---especially in the first 6 to 9 hours of the upcoming day
1 time period---with rainfall intensities and amounts expected to
decrease after this as the initial activity moves toward the lower
MS valley/central Gulf coast region.  The marginal risk area on
the latest excessive rainfall potential outlook over portions of
northeast TX was not changed with runoff issues possible in the
most intense heavy rain cores---especially if they occur over any
urban areas in the vicinity of Dallas to Waco.

Late Sunday morning into Sunday afternoon---another round of
precip expected to break out over portions of the Southern Plains
in an increasingly diffluent pattern ahead of additional southern
stream height falls moving northeastward from northern Mexico and
stronger upstream height pushing east from the southwest into the
southern high plains.  This next area of precip looks like it will
form farther to the north than the lead area---from north TX into
eastern OK Sunday afternoon---pushing into the lower AR river
valley toward the end of the day 1 period---with model consensus
for .25-50" amounts.

Western U.S.

The broad mean upper trof initially over the large portions of the
western U.S. will become increasingly separated into distinct
circulations day 1.  The northern portion of this trof will be
comprised of three fairly slowly moving circulations.  One moving
very slowly southward off the Pacific Northwest coast---while one
over the northern Rockies and another over southern
Alberta/southern Sask combine near the MT/Alberta/Sask border
region. Meanwhile---stronger and faster moving height falls will
eject out of the base of the trof tonight---pushing from southern
California---through the Southwest and emerging into the southern
high plains Sunday afternoon.  Overall---there is good model
agreement on what will be a large region of precip associated with
each circulation center.  Model consensus is for areal average
moderate totals---with locally heavy amounts possible in the
favored terrain regions from the Mogollon Rim of AZ---the central
Rockies of CO---through the Wasatch of UT and into the northern
Rockies of north central ID into western MT.



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