Weather Prediction Center

National Oceanic and Atmospheric Administration

US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
329 PM EDT Fri Jun 02 2023

Valid Monday June 05 2023 - Friday June 09 2023

Hazards:
- Flooding possible across portions of the Northern Plains.
- Flooding occurring or imminent across portions of the Northern Rockies and the Northern Great
Basin.
- Flooding likely across portions of the Central Rockies, the Central Great Basin, the Northern
Rockies, and the Northern Great Basin.
- Heavy rain across portions of mainland Alaska, Mon-Wed, Jun 5-Jun 7.
- High winds across portions of mainland Alaska, Mon-Tue, Jun 5-Jun 6.

Detailed Summary:

...CONUS...

The medium range timeframe (Monday, June 5 to Friday June, 9) will continue the theme of stagnant
upper-level flow featuring upper troughing/closed lows over the Southwest and Northeast, while an
upper-level high anchors over the north-central United States. No hazards are posted on the hazards
chart at this time. Precipitation chances are expected to be mostly light and spread from the
northern Great Basin to the Rockies and High Plains. Locally heavy rain cannot be ruled out for
these regions, but is difficult to pinpoint specific areas at the moment for potential hazards.
Precipitable water anomalies are forecast to be greatest over central/western Montana and nearby
surrounding areas. This part of the country has also been wet as of late and could be more
susceptible to flash flooding. However, current probabilities for 1"/24-hr and 2"/48 hr
probabilities between Thursday and Friday are low. The other area of potentially heavy rain is
across southern Florida, where a weak lingering frontal boundary could focus around 2" PWATs and
slow-moving storms. Guidance shows low probabilities for 2" of rain on Thursday and Friday over far
southern Florida and the Gold Coast.

Temperatures throughout the medium range will feature above average highs from the Pacific
Northwest through the northern Plains and parts of the Midwest. This equates to afternoon
temperatures into the upper 80s and low 90s. Given this early summer warmth doesn't reach hazardous
threshold or challenge daily records at this point, any potential much above normal temperature
areas were omitted.

...Alaska...

A combination of low pressure systems in the northern Pacific and into the Bering Sea, influenced
by the extratropical remnants of Typhoon Mawar, are forecast to eventually consolidate over the
eastern Aleutians/Alaska Peninsula. The model guidance has continued to indicate this will lead to
a significant plume of moisture/Atmospheric River ahead of the system into the Gulf of Alaska with
the potential for heavy rainfall totals along coastal locations. This is most likely to occur from
the eastern Alaska Peninsula through Kodiak Island, the southern Kenai Peninsula, and around Prince
William Sound Monday (June 5th) - Wednesday (June 7th). The amount of moisture that surges
northward still varies between model guidance, which has expected impacts on forecast rainfall
totals. However, even the lower end of the guidance still indicates daily totals of 1-2"+, which in
itself is still enough to raise some attention. Additional rainfall may also linger through the
remainder of the week, but should become more scattered and less intense. In addition, a moderate
pressure gradient will overspread the east Aleutians into the Alaskan Peninsula and southwest
mainland, with strong, gusty easterly winds most likely on Monday and Tuesday. Some notable gap
winds will also be possible. Guidance has trended slightly downward with the strength of the
associated low pressure system, possibly weakening the highest winds and lowering maximum rainfall
potential.

Snell