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Heat Builds in the West; Severe Thunderstorms and Heavy Rain in the Upper Midwest and Mid-Mississippi Valley; Extremely Critical Fire Weather in the Northwest on Saturday

A heat wave over the Southwest will intensify this week, peaking and expanding into the Intermountain West and northern High Plains this weekend. Severe thunderstorms and heavy rainfall are expected over parts of the Upper Midwest to mid-Mississippi Valley today. Critical to extremely critical fire weather conditions from the Northwest and the northern Great Basin on Saturday and Sunday. Read More >


292
FXZS60 NSTU 310137
AFDPPG

Area Forecast Discussion
National Weather Service Pago Pago AS
237 PM SST Thu Jul 30 2026

.Short term...

Satellite imagery has shown a trough just to the north of the
territory for this morning and early afternoon, but still
bringing more clouds than sun over American Samoa. No rainfall was
observed at the airport or recorded on the ASPA/University of
Hawaii Mesonet stations so far today.

A ridge from the south is now over the territory and interacting
with the trough to the north to produce winds around 20 mph with
higher gusts. These elevated winds are to continue through the
overnight hours. The risk of rain is only isolated to scattered
(20 to 30% chance) with an warm layer about 6000 feet over the
territory. This warm layer of air, called an inversion, will not
allow heavy rainfall to develop over the territory during this
time.

For Friday and early this weekend, the ridge begins to move
further away from the region. This is to slowly decrease winds and
increase rainfall. By Saturday, rainfall is forecast to be
scattered (40% chance) with east/southeasterly winds reaching up
to 15 mph. Temperatures remain below average.

.Long term...

For Sunday and early Monday, the ridge will be far enough away to
increase showers to scattered to numerous (50 to 60% chance).
Winds are forecast to be around 10 mph with temperatures back to
around normal.

However, for later Monday through the majority of next week,
another ridge is to push a trough back over the region early in
the week to increase the likelihood of showers to numerous
showers. Strong southeasterly trades develop by Tuesday through
the rest of the week to reach near Wind Advisory levels.

&&

.Marine...

The latest conditions from the PacIOOS buoys to the east of Aunu`u
and to the west of Tutuila shows seas around 9 feet. Seas have
been building yesterday and today due to winds increasing to a
fresh southeasterly breeze with a weak southerly swell moving
through the American Samoa coastal waters.

Winds are to slowly decrease Friday and into the weekend. Seas
will slowly ease as this occurs. A weak southerly swell is to
continue into Friday before becoming more a prodominent
east/southeasterly wind driven seas. However, with the long fetch
of winds, it is still projected to produce peak periods of around
10 to 12 seconds. Seas are likely to remain high enough with the
period timing to have surf continue reaching the lower levels of
the High Surf Advisory through Saturday. Seas may reach to below
Small Craft Advisory levels by Sunday and early Monday.

By later Monday, however, southeasterly trades begin to increase
once again to eventually reach a fresh southeasterly breeze. This
will likely create Small Craft Advisory conditions and high surf
conditions for early to at least the middle of next week.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...

A High Surf Advisory remains in effect through Saturday.
A Small Craft Advisory remains in effect.

&&

$$

LaPlante