580
FXUS21 KWNC 041944
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT June 04 2026

SYNOPSIS: Mid-level high pressure initially over interior eastern North America
is expected to deamplify while pushing northeastward early week-2, leaving a
lingering potential for extreme heat across parts of the central and eastern
Contiguous United States (CONUS) in its wake. Meanwhile, prevailing
above-normal temperatures, in combination with insufficient rainfall and
antecedent dryness, increases the potential for Rapid Onset Drought (ROD) over
the southwestern Great Lakes Region. Farther south, a persistent influx of
tropical moisture is expected along with the potential for slow-moving low
pressure development in the eastern Gulf. This enhances the risk of heavy
precipitation across most of Florida and adjacent areas through most of week-2.
At the same time, a slowly-amplifying mid-level ridge is expected to bring
gradually increasing temperatures and an increasing risk of extreme heat to the
Southwest, California Valleys, and some adjacent areas which is expected to
continue through most of week-2.

HAZARDS

Slight risk of extreme heat across much of the Plains, the Mississippi and
Lower Ohio Valleys, the southern Great Lakes region, and the central
Appalachians, Fri, Jun 12, 2026.

Slight risk of extreme heat in much of the Mid-Atlantic and lower Northeast,
Fri-Sat, Jun 12-13, 2026.

Slight risk of extreme heat in the Desert Southwest, California Valleys, and
some adjacent areas, Sat-Thu, Jun 13-18, 2026.

Slight risk of High Winds along the northern California and southern Oregon
coastline, Fri, Jun 12, 2026..

Slight risk of heavy precipitation over most of Florida, southern Georgia,
southeastern Alabama, and some adjacent areas, Thu-Tue, Jun 13-18, 2026.

Rapid onset drought possible for parts of northeastern Illinois and
northwestern Indiana.

DETAILED SUMMARY

FOR SUNDAY JUNE 07 - THURSDAY JUNE 11:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR FRIDAY JUNE 12 - THURSDAY JUNE 18: At the start of week-2, the models all
depict a mid level ridge stretching from Canada southward into the interior
CONUS that is in the process of deamplifying and pushing eastward. As a result,
unusually hot weather that built into the central and eastern CONUS during
week-1 is expected to moderate early week-2, but a lingering risk of extreme
heat is anticipated during the first day or two of the period from the central
CONUS through portions of the East Coast. Forecast uncertainty is introduced by
poor model agreement on the location and evolution of this mid-level ridge,
which results in differences in the placement of the greatest heat risk. The 0z
GEFS mean depicts a mid-level ridge axis extending from Canada through the
western Great Lakes while the Canadian ensemble (CMCE) mean and European
ensemble (ECENS) mean place the axis closer to the Northeast at the outset of
week-2. Today there is less spread between the GEFS and the other ensemble
means, and there good agreement on the strength of the mid-level ridge as it
dissipates, but the GEFS still shows the hottest weather and greatest
temperature anomalies over the Great Plains and Mississippi Valley on day 8
(Fri Jun 12) while the ECENS and to a lesser degree the CMCE place the largest
anomalies farther east over the Great Lakes, Mid-Atlantic, and lower Northeast.
The Probabilistic Extremes Tools (PETs) from the GEFS and ECENS show similar
differences in the forecast location of the greatest chances for extreme heat.
The likelihood that temperatures will be among the warmest 15 percent of
recorded history exceed 40 percent in the GEFS PET from the Upper Mississippi
Valley into the central Great Lakes Region while the ECENS PET depicts chances
exceeding 60 percent from Upstate New York through the central Appalachians.
Because of these discrepancies, a broad area with a slight risk of extreme heat
is posted from portions of the Great Plains eastward through the Mid-Atlantic
and lower Northeast. The extreme heat risk is removed from the Appalachians,
where none of the guidance indicates a significant potential for extreme heat.
West of the Appalachians, the slight risk is removed after the first day of the
period. Farther east, closer to the decaying mid-level ridge, the slight risk
of extreme heat continues for an additional day. Also, while the best odds for
highly anomalous temperatures cover the northern tier of the eastern CONUS, the
slight risk of extreme heat has been removed since there seems to be little
chance for temperatures to rise much above 90 deg. F there. In contrast, there
are low but non-trivial chances for temperatures to reach 100 deg. F farther
south across the central tier of the eastern CONUS. 500-hPa heights return to
near normal by the third day of the period (Sun Jun 14), ending the extreme
heat threat.



For the past several weeks, precipitation has been significantly below normal
over portions of the western Great Lakes region and adjacent parts of the
Mississippi Valley. Recently, the U.S. Drought Monitor has highlighted
abnormally dry conditions across this region, and the weekly issue released
this morning introduced some moderate drought in portions of this area. The
week-2 precipitation outlook depicts marginally enhanced chances for
above-normal precipitation across this area, but the expected hot weather and
associated increases in evaporative moisture losses, in conjunction with the
elevated human and ecological demand for surface water inherent to summertime,
makes it likely that the precipitation will not be sufficient to offset surface
moisture losses. As a result, a potential for rapid-onset drought (ROD) is
maintained across much of northern Illinois and northwestern Indiana. Farther
in the areas where drought was introduced this week, some relatively quick
deterioration into more severe drought classifications is possible. Elevated
ROD potential was removed from areas farther west in parts of Iowa and
Minnesota, where heavy short-term rains (1.5 to 2.5 inches) over the next
several days should be enough to preclude rapid drought development there,
although less dramatic deterioration over the next few weeks is possible.



A departing mid-level trough is expected to leave low surface pressure in its
wake over the interior West. Meanwhile, mid-level ridging is forecast to build
toward or into the West Coast, resulting in higher surface pressures. The
resulting pressure gradient supports a slight risk of high winds over parts of
northern coastal California and the Pacific Northwest early week-2 (Jun 12).
Surface pressure forecasts from the ensemble means highlight this potential,
and the PETs derived from the GEFS and ECENS show somewhat enhanced chances for
winds to reach the top 15 percent of the climatological range. Models have
trended a bit farther north relative to yesterday, placing the greatest
positive 500-hPa height anomalies near the Pacific Northwest. This reduces the
chances for high winds farther south, and the slight risk of high winds is
removed from central and southern sections of the California Coast.



Some guidance continues to highlight the potential for a wave of low pressure
to develop west or southwest of Florida in conjunction with a potent flow of
tropical moisture from into the Gulf and adjacent southeastern CONUS. The
models have been inconsistent in handling the evolution of this potential
system, which is not unexpected given the relatively subtle mid-level features
that determine the evolution of low pressure in lower latitudes during summer.
Today, the preponderance of models agree that this system will form and
increase chances for heavy precipitation across most of Florida and nearby
portions of the Southeast, with the best chances across southern Florida. This
system is forecast to drift northward over the course of week-2, but after
mid-week, models significantly diverge from each other on the timing,
placement, and intensity of the heaviest rainfall as well as the track of any
surface low pressure that develops. The dynamical European model (ECMWF) drops
4 to 6 inches of rain on southern Florida through the middle of week-2, and
forecasts 2 or more inches into the central Florida Peninsula. The dynamical
GEFS Artificial Intelligence model is similar, but restricts amounts over 4
inches to the southwestern coastline, and brings more than 2 inches through
almost all of the Florida Peninsula. The ECENS mean and the ECENS Artificial
Intelligence ensemble mean depict maximum amounts of 2-3 inches south of Lakes
Okeechobee or along the southwestern Florida coast, respectively, with amounts
of an inch or more expected across the rest of the state. During the last half
of week-2, the models diverge even further, bringing the heaviest rainfall
farther north, anywhere from the central Gulf Coast to the South Atlantic
Coastline. Most models eventually bring an additional 1 to 2 inches of rain to
northern Florida and anywhere from the central Gulf Coast to the interior
Southeast to the South Atlantic coastline, depending on the model. Regardless
of the specifics, there are enough indicators favoring heavy precipitation to
support a slight risk of heavy precipitation across most of Florida and
adjacent parts of the Deep South. The risk extends through most of week-2, but
the timing, location, and magnitude of any heavy rainfall is highly uncertain.



Most tools depict a mid-level ridge amplifying in the eastern North Pacific
that builds slowly toward or into the western CONUS. As this evolves,
temperatures are expected to slowly increase across the western CONUS,
resulting in a slight risk of extreme heat across the Desert Southwest and
California Valleys during most of week-2. The ECENS mean is more robust with
this solution than the GEFS and CMCE means, but there is less model disparity
than yesterday. The mean solution from the new GEFS artificial intelligence
ensemble (AIGEFS) generally supports the ECENS scenario, as does dynamical
European artificial intelligence model (ECMWF-AI) ensemble mean. Temperatures
are expected to reach 100 to 105 deg. F for several days during the middle of
week-2, with the ECENS mean forecasting temperatures of 110 to 115 deg. F in
the most arid locations near the lower Colorado River and Mexican border.
Today, the GEFS and ECENS forecast the mid-level ridge to retrograde toward the
central Pacific later in the period, potentially bringing temperatures a little
closer to normal. The CMCE, however, locks the ridge in place along or near the
West Coast. These divergent solutions lower confidence in the forecast end of
the slight risk of extreme heat.



In Alaska, river ice breakup season is ending, but many rivers north of the
Brooks Range remain icebound. River breakup flooding can occur with little or
no notice as conditions on frozen rivers can change quickly, so please check
with the Alaska Pacific River Forecast Center for the latest conditions and
advisories.

FORECASTER: Rich Tinker

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