Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
542 PM EDT Thu Sep 29 2022

Valid 00Z Fri Sep 30 2022 - 00Z Sun Oct 02 2022

...Conditions will improve this evening in the Florida Peninsula as
Hurricane Ian exits into the Atlantic Ocean...

...Ian is forecast to make a second landfall in South Carolina on Friday
as a Category 1 hurricane, with strong winds and storm surge near the
coast, and widespread heavy rain spreading well inland across the
Southeast and Mid-Atlantic...

...Cool high pressure system will dominate the eastern half of the country
outside of Ian as heat in the West will give way to rain and cooler
temperatures moving into the Pacific Northwest and the northern Rockies...

Hurricane Ian has exited the Florida Peninsula after making landfall near
Cayo Costa, Florida yesterday afternoon as a category-4 major hurricane.
Conditions along the western Florida coastline will improve this evening
as the last convective bands of the tropical system push eastward into the
Atlantic. Now in the open waters of the warm ocean, Ian is forecast to
make landfall tomorrow afternoon in South Carolina with hurricane-force
winds and torrential rainfall expected to impact much of the northern GA &
SC coastline. Ian's continued interaction with a front draped around the
system will help focus an axis of widespread heavy rainfall as a warm
front moves onshore to the northeast of Ian. Current forecasts indicate
that widespread 3 to 5 inches of rain could fall across the Mid-Atlantic,
increasing to 6 to 10  inches near where Ian is forecast to make landfall.
As a result, a Moderate Risk of Excessive Rainfall is in effect for much
of South Carolina,central North Carolina and southwestern Virginia on
Friday. After landfall later on Friday, Ian is expected to lose tropical
characteristics and become an extratropical low while moving inland toward
the southern Appalachians by Saturday morning. This will allow rainfall to
spread northward into much of the Mid-Atlantic, resulting in a Slight Risk
of Excessive Rainfall being hoisted for much of West Virginia,
northeastern Kentucky, western Virginia, as well as the southern New
Jersey coastline and the Delmarva Peninsula on Saturday.

Elsewhere, fall-like cool temperatures will prevail across much of the
eastern half of the country outside of Ian under the influence of an
expansive high pressure system from Canada. Freeze Warnings and Frost
Advisories are in effect this morning for much of interior New England,
upstate New York, and Pennsylvania through tomorrow morning as nightime
temperatures will approach and dip below freezing. The high pressure
system will weaken by the weekend, allowing temperatures to rebound, but
should also help to keep much of Ian's rainfall to the south, leaving
northern New England dry.

Further west, above-average temperatures will give way to rain and cooler
temperatures as a low pressure system moves into the Pacific Northwest,
reaching the northern Rockies by Friday and into the weekend.
High-elevation wet snow is  possible over northwestern Wyoming by Friday
morning. The Desert Southwest will still be hot as afternoon temperatures
are forecast to soar to near the century mark for the next couple of days.
Meanwhile, monsoonal moisture is forecast to return for the Four Corners
region.


Russell/Kong


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