Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 251 PM EDT Sat May 22 2021 Valid 00Z Sun May 23 2021 - 00Z Tue May 25 2021 ...Big temperatures contrasts expected between the western, and central to eastern U.S... ...Scattered Thunderstorms through the Plains will produce locally heavy rains, isolated Flash Flooding and the risk of Severe Weather... ...A Fire Weather threat to continue for portions of the Southwest... The mid to upper level flow will remain highly amplified across the lower 48 over the next two days with a strong closed low lifting northeast from the Great Basin and through the Northern Rockies, while an upper level ridge along the Mississippi pushes east into the Southeast. In this flow regime, a strong frontal boundary will separate much below average temperatures across the Great Basin and Rockies region with much above average temperatures from the Northern to Central Plains, eastward across much of the Mississippi Valley and eastern U.S. Temperatures are expected to be 10 to 20 degrees below average on the cold side of this front across the Great Basin and Rockies , while temperatures will equally above average on the warm side of the front from the Northern to Central Plains, eastward across much of the Mississippi Valley and eastern U.S. Some record high temperatures are possible Sunday in the urban corridor from Boston to Washington DC, where highs are forecast in the upper 80s to low 90s. While temperatures are expected to be below average across portions of the west, no records are forecast, although late season snows are possible across portions of the Northern Rockies on Sunday. The above average temperature region will also encompass all of the historical region of the Brood X periodic cicada. This will ensure additional warming of the soil and expansion of the regions of emergence and continued active cicada singing where they have already surfaced. Above average levels of moisture expected to continue to stream northward off the western Gulf of Mexico across much of the Plains over the next two days along and ahead of the above mentioned strong front. This will support widespread scattered thunderstorms through the Plains with locally heavy rains, isolated flash flooding and the threat of severe weather. Contrasting this will be a continued fire weather threat across portions of the Southwest from southern to eastern Arizona, western New Mexico and southern Utah where the combination of low relative humidities and gusty winds will support a fire risk. Oravec Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php