Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
403 PM EDT Tue Sep 27 2022

Valid 00Z Wed Sep 28 2022 - 00Z Fri Sep 30 2022

...Hurricane Ian is forecast to make landfall on the west coast of Florida
late Wednesday; slow forward motion of Ian will likely prolong impacts
from high winds, heavy rain, and flooding even for areas further inland...

...Cool weather expected to persist across the Northeast and Great Lakes
through at least mid-week...

...Well above average temperatures across much of the West, with excessive
heat continuing over parts of southern California, followed by arrival of
rain and cooler temperatures over the Pacific Northwest later on
Wednesday...

Hurricane Ian continues to re-intensify as it pulls away from Cuba and
begins its approach towards the western coast of Florida. The latest NHC
forecasts depict the storm moving northward this evening, bypassing the
Florida Keys to the west before making landfall as a major hurricane
tomorrow evening south of Tampa Bay, FL. With the storm just 100 miles
southwest of Key West, outer bands of Hurricane Ian have already begun
impacting much of southern Florida, with heavy rain ongoing. As Ian
continues its northward progression, winds will begin to increase to
hurricane force along coastal portions of Florida. Ian is forecast to slow
down its forward motion as it begins to interact with a stationary front
settling across northern Florida.  This interaction will likely prolong
the threat of heavy rain and high winds near and to the northeast of where
Ian makes landfall.  How fast/slow Ian moves will partly depend on how
fast/slow an amplified upper trough retreats into eastern Canada as well
as how fast/slow Ian interacts with the front. As a result of the heavy
rain and slow movement speed, a Moderate Risk of Excessive Rainfall is in
place for southern FL in the Day 1 timeframe, with a High Risk of
Excessive Rainfall being hoisted in the Days 2 & 3 timeframes across much
of FL. As heavy rain falls on top of already wet grounds, widespread
instances of flooding are expected. In addition to the rainfall threat,
the Storm Prediction Center has included central and southern FL in a
Slight Risk for Severe Thunderstorms through Thursday due to the threat of
tornados. The combination of life-threatening storm surge, and
hurricane-force winds, in addition to the likelihood of flooding
associated with heavy rainfall, will lead to a very dangerous situation
across central and southern Florida through Thursday as Hurricane Ian
makes landfall.

Elsewhere, cool, fall-like temperatures will continue across the Midwest
and Northeast through Thursday as a deep, upper-level trough moves
eastward. Most of the Upper Midwest, Great Lakes, and interior Northeast
will see highs in the upper-50s and low-60s through Thursday. Freeze
Warnings have been issued for portions of the northern Great Lakes region,
with Frost Advisories also in effect in the Upper Mississippi Valley as
Wednesday morning lows will bottom out in the mid-30s.  Southern portions
of the Midwest as well as the coastal Northeast will see highs in the
mid-60s to low 70s. Temperatures across the Southeast will cool from the
upper 70s/low 80s today to the mid-70s Wednesday and Thursday. Conditions
are forecast to remain fairly dry across the region, outside of areas
along the Lake Erie and Ontario shorelines in interior NY & PA, as strong
winds blowing cool air over the warm lakewater will lead to heavy
lake-effect rainfall through this evening. As a result, a Slight Risk for
Excessive Rainfall has been hoisted along the Lake Ontario shoreline in
western NY.

Further west, above-average temperatures will remain over the region as a
strong upper-level ridge moves eastward. Temperatures are forecast to soar
into the 100s and 90s for the desert southwest and interior southern
California, leading to the issuance of Excessive Heat Warnings and Heat
Advisories in the Los Angeles and San Diego metro areas through Wednesday
evening. By late Wednesday, moisture ahead of a Pacific cyclone is
forecast to reach the Pacific Northwest, bringing a period of unsettled
weather further inland as well as a general cool down to the region.  Rain
associated with the system is expected to reach the northern Rockies
Wednesday night/Thursday morning.  Some monsoonal moisture is forecast to
return near/west of the Four Corners region.

Russell/Kong


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