Weather Prediction Center

National Oceanic and Atmospheric Administration

US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
408 PM EDT Tue Oct 03 2023

Valid Friday October 06 2023 - Tuesday October 10 2023

Hazards:
- Heavy rain across portions of south Texas, Fri, Oct 6.
- Heavy rain across portions of the Northeast, Fri-Sat, Oct 6-Oct 7.
- Flooding occurring or imminent across a small portion of Florida.
- Frost/freeze across portions of the Central/Northern Plains, and the Upper Mississippi Valley,
Fri-Sat, Oct 6-Oct 7.
- Heavy rain across portions of Southeast Alaska, Fri-Sat, Oct 6-Oct 7.

Detailed Summary:

...CONUS...

The medium range period (Friday, October 6 to Tuesday, October 10) will feature a strong upper
level trough moving across the Northern Plains and the Upper Midwest/Great Lakes this weekend.
Behind the attendant cold front, a chilly airmass with overspread much of the central U.S. with
minimum temperatures dropping into the 30s Friday and Saturday mornings for many across the High
Plains to central/northern Plains and parts of the Upper Midwest. Continuing breezy conditions on
Friday should limit the overall frost/freeze threat, except for possibly portions of the northern
High Plains. However, as conditions calm Friday into Saturday, a more widespread threat is expected
to develop farther east. Despite this being around the normal time of year for reaching the first
frost/freeze for most of these areas, this entire region (outside of the terrain) has not seen
temperatures this low yet this year. For this reason, kept the area introduced yesterday for
frost/freeze, with some modifications based on the latest guidance data.

The associated cold front will swing through Texas late this week with upper level support for some
heavier showers and thunderstorms, mainly on Thursday but possibly extending into Friday. The WPC
Day 4 Excessive Rainfall Outlooks shows a marginal risk for Friday across far south Texas and so a
heavy rain hazard area remains on the map for today in that region. Across the Northeast, models
show good agreement the upper trough will close off into a deep upper low and meander over the
region for a few days. This should support heavy rainfall with models indication decent chances for
at least an inch of rain Friday into Saturday. The WPC EROs for Friday and Saturday show a marginal
to slight risk for flash flooding, especially considering some of this area is particularly
susceptible to flooding after recent heavy rains, and so a heavy rain area is on the map for this
region.

Conditions across the CONUS after Saturday should be mostly calm and dry. A deepening upper trough
and cold front into the Pacific Northwest early next week will be accompanied by modest rainfall,
but at this time, amounts look to remain below the hazards threshold for a heavy rain area.


...Alaska...

A low pressure system is forecast to approach Alaska mid-week and stall near the eastern Aleutian
Islands through much of the upcoming weekend. This will allow a stream of Pacific
moisture/atmospheric river to setup over much of Southeast Alaska, which will likely cause multiple
periods of heavy rainfall through the weekend. The worst of the rains look to end by the start of
the hazards period on Friday, but renewed energy into the region could support additional, at least
locally heavy rainfall, through Saturday. This system may also bring the potential for freezing
rain in the Kuskokwim Valley where temperatures will be hovering around freezing, but too localized
for any areas on todays hazards map. A strong pressure gradient between this surface low in the
Gulf and high pressure across the Arctic could bring a period of gusty winds to portions of
interior Alaska. Another low pressure system will approach early next week, and bring another
chance of heavy rainfall to the Alaskan Panhandle on Monday, and a heavy rain area was included
across this region on todays map.

Santorelli