Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
345 PM EDT Tue Jun 06 2023

Valid 00Z Wed Jun 07 2023 - 00Z Fri Jun 09 2023

...Much above average temperatures from the Northern Plains to the Pacific
Northwest while the Southwest/California and the Northeast remain below
average...

...Numerous and Widespread Air Quality Alerts from the Northeast to the
Great Lakes as well as for other urban areas in the central/eastern U.S...

...Scattered to widespread showers and storms with the risk for flash
flooding continue from the High Plains into the Intermountain West...

The upper-level pattern over the CONUS will remain rather stagnant the
next couple of days with lows over the Northeast and California and
ridging in between. This will keep temperatures for many locations from
New England southwest into the Mid-Atlantic, Appalachians, and Ohio
Valley, as well as California and the Southwest, as much as 10-20 degrees
below average Wednesday and Thursday. Highs for portions of New England
will only be in the 50s and 60s, with 70s generally expected further to
the south. Similarly, most of coastal California should remain in the 60s
while highs will be warmer, but still below average, into the interior
valleys and Desert Southwest, with 80s to low 90s expected. In contrast,
under the ridging stretching northwestward over the Plains and Northwest,
temperatures will be running as much as 10-20 degrees above average. Highs
Wednesday and Thursday in the Northern Plains and interior Pacific
Northwest will be in the upper 80s to low 90s, with 80s to near 90 for the
I-5 urban corridor as well on Thursday. 

Another notable event in this pattern, with northwesterly flow around the
northeastern upper-level low, is the recurring, widespread smoke streaming
into the Great Lakes and Northeast due to wildfires in Canada. Numerous
Air Quality Alerts remain in effect throughout the region late Tuesday,
with the expectation that not much will change about the pattern over the
next couple of days. While not quite as thick or widespread, smoke has
also continued to spread further over portions of the central and eastern
CONUS, with Air Quality Alerts for many of the regional urban areas. In
addition, breezy winds and low humidity over portions of the Lower Great
Lakes into the Mid-Atlantic, where conditions remain very dry due to a
recent lack of rainfall, have prompted an Elevated Risk of Fire Weather
from the Storm Prediction Center for Wednesday.

Showers and thunderstorms will be possible along a backdoor cold front
sinking southwestward through portions of the Missouri/Mississippi Valley
and into the Southeast. Rainfall totals should generally remain light to
moderate, expect for South Florida where more abundant tropical moisture
will lead to heavier downpours. Scattered to widespread showers and
thunderstorms will also continue along the High Plains and into the
Rockies. Anomalously moist southeasterly upslope flow will contribute to
the risk for locally heavy downpours and rainfall totals, with Slight
Risks of Excessive Rainfall in effect for portions of the central/southern
High Plains into the central Rockies Wednesday and for portions of Montana
and Idaho Wednesday and Thursday. Scattered instances of flash flooding
will be possible with wet antecedent conditions in place from recent
episodes of heavy rainfall. Storms will also continue over portions of
northern California into the northern Great Basin as the upper-level low
slowly shifts northward. There will be an attendant risk for a few
isolated instances of flash flooding, particularly for terrain sensitive
areas as well as burn scars.

Putnam


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