Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Mon Apr 12 2021
Valid 00Z Tue Apr 13 2021 - 00Z Thu Apr 15 2021
...A slow moving, blocked upper level pattern to support late season snows
across portions of the Northern Plains, Central Rockies and northern Great
...An Elevated to Critical Fire Weather threat expected across the
Southwest Tuesday and Wednesday...
...Additional Heavy rains possible along the Central Gulf Coast and Lower
The mid to upper level flow pattern across much of North America will
continue to exhibit a high degree of blocking, resulting in very slow
moving systems affecting large portions of the nation. The lead slow
moving upper low over the Northern Plains/Upper Mississippi Valley region
will continue to support late season accumulating snows across northern to
eastern North Dakota into northwestern Minnesota Monday night night into
Tuesday. The snow threat from this system will decrease significantly
late Tuesday into Wednesday with only light snow possible from the
Northern Plains into the Upper Great Lakes.
While the lead mid to upper level system meanders over the Northern
Plains/Upper Mississippi Valley region, a second slow moving system will
develop over the Pacific Northwest on Tuesday and sink only slowly
southward into the northern Great Basin by Wednesday. This system will
not have a lot of associated precipitation initially, but should expand
its precipitation effects from Tuesday night into Wednesday across the
northern Great Basin and into the Central Rockies. Late season heavy
snows are possible across the Rockies of Colorado and Wyoming and across
the Wasatch and Unitas of Utah.
Additional heavy rains are on tap late Tuesday into Wednesday across the
Lower Mississippi Valley and Central Gulf coastal regions. These areas
have been wet over the past week with rain totals 200-300% of average.
This has resulted in high stream flow values and saturated soils. The
additional heavy rainfall threat will also lead to an increasing threat of
flooding across portions of the Lower Mississippi Valley and Central Gulf
coast late Tuesday into Wednesday.
In contrast to the wet conditions along the Central Gulf Coast into the
Lower Mississippi Valley, dry conditions, low relative humidities and
gusty winds will support an Elevated to Critical Fire Weather Threat over
the Southwest Tuesday and Wednesday. With the large scale pattern not
expected to change much over the western U.S., with the above mentioned
slow moving mid to upper level system, there will likely continue to be a
fire weather threat over the Southwest into the end of this week.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php