Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
351 PM EDT Fri Oct 06 2023

Valid 00Z Sat Oct 07 2023 - 00Z Mon Oct 09 2023

...Post Tropical Cyclone Philippe to bring heavy rainfall with the risk of
flash flooding as well as gusty winds to the Northeast Saturday...

...Much cooler Fall temperatures overspreading the central and eastern
U.S. this weekend with a freeze expected Saturday morning for portions of
the Northern/Central Plains...

...Much above average temperatures and dry conditions for the West...

The main weather story over the next couple of days will be the rainfall
associated with Post Tropical Cyclone Philippe in the Northeast. A
deepening upper-level low and associated surface low/frontal system over
the Great Lakes/southeastern Canada will shift eastward over the Interior
Northeast as Philippe approaches from the south. It is expected that
Philippe will eventually be absorbed into this broader upper-level low
that will linger over the region through the weekend. A Slight Risk of
Excessive Rainfall (level 2/4) is in place Saturday through early Sunday
for portions of Upstate New York and New England where two corridors of
heavy rainfall and the risk for flash flooding are expected to set up. The
first will be a north/south corridor through the Hudson River and
Champlain Valleys along the eastward advancing cold front where increasing
moisture from the approach of Philippe and strengthening dynamics aloft
will lead to numerous storms with the potential to produce locally heavy
downpours. The second will be in eastern Maine for rainfall more directly
associated with Philippe as the system tracks onshore later Saturday/early
Sunday morning. Even more anomalous surface moisture and additional
upper-level dynamics from the approaching trough will help enhance
rainfall totals. In addition to the heavy rainfall, gusty winds are
expected for eastern Maine along the storm's track, as well as high surf
along the New England Coast. Philippe is expected to move quickly into
Canada during the day Sunday, with the threat for heavy rainfall likely
diminishing in the morning.

While much of the attention will be on Philippe, the frontal system will
also bring some lake-effect showers to the Great Lakes this weekend, as
well as much cooler Fall temperatures to the eastern half of the country
after what has been a warm start to October. Forecast highs this weekend
will range from the 40s and 50s for the Great Lakes/Midwest, the 50s and
60s for the Northeast southwest through the Ohio Valley into the Central
Plains, and the 60s and 70s for the South and Southern Plains. Numerous
Frost and Freeze related advisories are in effect for portions of the
Northern and Central Plains as temperatures drop into the upper 20s to low
30s Saturday morning, the first freeze of the season for much of the
region. Temperatures will remain warmer Saturday in Florida ahead of the
cold front with highs in the 80s to low 90s, but drop into the 70s to low
80s for all but South Florida on Sunday following the front passage. Some
scattered showers and thunderstorms will be possible for South Florida as
well.

Meanwhile, as the upper-level low/trough amplify over the East, an
upper-level ridge will remain in place over the West with much above
average temperatures and dry conditions this weekend. A handful of record
tying/breaking highs will be possible. Highs are forecast in the 70s and
low 80s for the Pacific Northwest, Great Basin, and Northern Rockies, with
90s to low 100s in the Desert Southwest and the central California
Valleys. Heat Advisories remain in place for portions of inland central
and southern California for highs into the 90s Saturday. A storm system
will approach the Pacific Northwest late Sunday with some light coastal
showers possible.

Putnam


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