Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
322 AM EDT Fri May 12 2023

Valid 12Z Fri May 12 2023 - 12Z Sun May 14 2023

...Heavy rain, flash flooding and severe weather likely across large
portions of the Plains...

...Much above average to record heat building across the Pacific
Northwest, while below average temperatures expected across large portions
of the Plains...

Mean troughing in the West will eject waves of potent upper energy into
the the Great Plains, while upper ridging builds over the Pacific
Northwest this weekend. A surface cold front and dry-line have, and will
continue to be the focus for heavy rainfall, flash flooding and severe
weather across the Great Plains today. There is a Moderate Risk of
Excessive Rainfall leading to Flash Flooding over portions of the Rio
Grande Plain today as 2-3+ inches of rain are expected for many areas. The
Storm Prediction Center issued a Slight Risk of Severe Thunderstorms for
much of Texas and into Oklahoma due to the potential for very large hail
and wind damage from storms. Elsewhere, there's a Slight Risk of Excessive
Rainfall leading to Flash Flooding over much of the Dakotas and Nebraska
today as potent surface low pressure in the Front Range directs moisture
and instability up into the Northern Central Plains. 1-2 inches of
rainfall is expected today. The Storm Prediction Center issued an Enhanced
Risk of Severe Thunderstorms over portions of southeastern South Dakota,
eastern Nebraska, western Iowa and northwestern Missouri, where a few
tornadoes, very large hail and wind damage are especially possible.

Another round of heavy rainfall is expected to impact Texas and the
greater Southern Plains region on Saturday. The heaviest rainfall will
occur over already saturated soils in southern Texas where between 2-3
additional inches of rainfall are expected. Thus, another Moderate Risk of
Excessive Rainfall is in place from the Rio Grande Plain across to the
Gulf Coast of Texas. A complex of thunderstorms will develop over portions
of South Texas early Saturday morning and move toward the coast. A Slight
Risk of Severe Thunderstorms is in effect for this scattered convection,
with potential for locally damaging winds and hail. Elsewhere on Saturday,
there are Slight Risks of Excessive Rainfall and Severe Thunderstorms over
parts of southern Minnesota, Iowa and northwestern Illinois where 1-2
inches of rainfall and locally damaging winds and hail are possible.

An upper ridge will build over southwestern Canada and the Pacific
Northwest this weekend leading to the advection of anomalously warm air
into the area. High temperatures in the 80s and 90s are possible across
the West Coast this weekend. This will constitute a 20-30 degree departure
from normal for much of the region. Parts of the Pacific Northwest, in
particular, could reach or break high temperature records. Elsewhere,
cooler air will filter in along the foothills of the Rockies this weekend
with high temperature departures of 15-25 degrees below average from
eastern Montana to western Texas. Temperatures in the East will remain
above average through the weekend.

Kebede


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php