The Nation’s Weather

…The risk for severe weather and flash flooding will shift eastward
across the Mississippi Valley and South on Tuesday and across the
Southeast and Mid-Atlantic on Wednesday …

…Above average temperatures continue across parts of Texas, the Florida
Peninsula, and across California and the Southwest…

…Much of the northern and eastern tier of the country will see showery
and cool conditions as an area of low pressure matures and moves eastward
from the Plains to the Mid-Atlantic…

A maturing central U.S. storm system is producing dangerous storms this
afternoon and expected to continue through this evening. The Storm
Prediction Center has a Moderate Risk across much of the southern Plains
and into the western zones of the Mississippi Valley. All severe weather
hazards are likely: large hail, damaging winds, and a few strong tornadoes
are possible. Additionally, a Moderate Risk for Excessive Rainfall is
active across most of northern Arkansas and southern Missouri with a
Slight Risk extending across much of the Mississippi Valley. Storms are
expected to expand in coverage and may train. Some locations could see 4-5
inches in the near term through the overnight. Turn around, don’t drown !
The severe weather risk and flooding risk will shift east across the
Tennessee and Ohio Valleys for tomorrow. The current severe weather
outlook has an Enhanced Risk for these regions with a mix storm mode of
organized clusters and discrete supercells. Hazards of a few strong
tornadoes, damaging winds, and hail are messaged. The flooding risk will
not be as high tomorrow, but scattered flash flooding will certainly be
possible where thunderstorm complexes train and drop high hourly rainfall
rates. Because of this threat, WPC has issued a Slight Risk for Excessive
Rainfall across much of the Tennessee and Ohio Valley region. On
Wednesday, the Southeast and southern Mid-Atlantic have a Marginal Risk
for severe weather as thunderstorms along a cold front could produce some
gusty winds and contain a tornado or two. A Marginal Risk for Excessive
Rainfall is valid for much of the Mid-Atlantic and Northeast as a shield
of rainfall in association with the storm system may bring 1-2 inches of
rainfall. Some isolated flooding could be possible in sensitive urban
areas and small streams.

The Heat Advisories and Warnings over Texas have been allowed to drop as
temperatures have cooled off to an extent. However, temperatures will
remain above average. High temperatures are expected to be in the low to
middle 90s across the gulf shores and the upper 90s to even low 100s for
parts of central Texas to the Rio Grande region. My home state of Florida
will remain around 5-10 degrees above average as ridging continues to hold
strong and brings warm and mostly dry conditions. For the specifics,
middle 90s are expected for the short range. The Heat Risk Index has some
of the metros of Orlando and Miami beginning to enter the Major category.
People should avoid activities in the peak heating hours and stay
hydrated. The Southwest will also see heat build as mid-level ridging
takes hold over the region. Moderate and Major Heat Risk is expected
tomorrow, Wednesday, and Thursday for most of the Desert Southwest,
including the Los Angeles metro. High temperatures will be in the middle
to upper 90s across the California valleys to the low 100s across the
Deserts.

On the other side of the coin, much of the northern and eastern U.S. will
be cool and unsettled as general upper troughing and rain from the low
pressure system traversing from the Plains to the Mid-Atlantic. Widespread
morning low temperatures in the 30s and 40s across the Inter-Mountain West
and Northern Plains will be possible for Tuesday and Wednesday mornings.
Low temperatures may bring frost potential across upper parts of the
Northeast on Tuesday morning. Low temperatures will then remain in the
lower to middle 40s through Thursday across the Northeast. For
precipitation, much of the Midwest and northern Plains will see rain
showers for Tuesday and Wednesday with cool high temperatures in the 40s
and 50s. The Mid-Atlantic and Northeast will have a particularly wet and
windy Wednesday and Thursday with below average high temperatures in the
50s and 60s. Most of the areas discussed could see high temperatures more
than 20 degrees cooler than expected for mid-late May.

Wilder

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