048
FXUS21 KWNC 141933
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT June 14 2024

SYNOPSIS: A heat wave is forecast to be ongoing across portions of the Midwest,
Mid-Atlantic, and Northeast as well as much of the Interior West at the outset
of week-2 associated with broad mid-level high pressure over much of the
contiguous U.S.(CONUS). Enhanced southerly flow and an influx of tropical
moisture favor elevated chances of heavy precipitation and potential flooding
near the Gulf of Mexico coast, although there is uncertainty regarding timing
and coverage of the heaviest precipitation. High temperatures and antecedent
rainfall deficits result in the potential for Rapid Onset Drought for portions
of the Corn Belt and Mid-Atlantic.

HAZARDS

Moderate risk of excessive heat across portions of the Ohio Valley, Northern
Appalachians, Mid-Atlantic, and Northeast Sat-Mon, Jun 22-24.

Moderate risk of excessive heat across portions of the Central Great Basin,
Sat-Tue, Jun 22-25.

Slight risk of excessive heat across portions of the central and eastern CONUS,
Sat-Wed, Jun 22-26.

Slight risk of excessive heat across portions of the western CONUS, Sat-Wed,
Jun 22-26.

Moderate risk of heavy precipitation along the western and central Gulf of
Mexico coast, Mon-Wed, Jun 24-26.

Slight risk of heavy precipitation for much of the Gulf Coast and Lower
Mississippi Valley, Sat-Thu, Jun 22-27.

Slight risk of heavy precipitation across portions of the Northern Plains and
Upper Mississippi Valley, Sat-Sun, Jun 22-23.

Slight risk of high winds across portions of the eastern Rockies, and the
Central and Southern Plains, Sat-Mon, Jun 22-24.

Flooding possible across portions of the Gulf of Mexico coast.

Rapid Onset Drought Risk for parts of the eastern Corn Belt and Mid-Atlantic.

DETAILED SUMMARY

FOR MONDAY JUNE 17 - FRIDAY JUNE 21:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SATURDAY JUNE 22 - FRIDAY JUNE 28: Todays ensemble solutions from the GEFS
and ECMWF are showing good continuity with yesterday, particularly with regard
to the spreading mid-level ridge over the CONUS at the outset of week-2.
Guidance from the GEFS and ECMWF Probabilistic Extremes Tools (PETs) continue
to depict at least a 40% probability of daily maximum temperatures exceeding
the 85th percentile for portions of the Ohio Valley, Mid-Atlantic, Northern
Appalachians and Northeast on Jun 22. Todays model solutions do not favor a
weakening of this ridge translating to the PETs indicating at least a 40%
chance of temperatures exceeding hazardous thresholds through the 24th.
Therefore, a moderate risk for excessive heat is posted for areas highlighted
above for Jun 22-24. By the 24th  the GEFS and ECMWF solutions diverge, with
the GEFS favoring cooler conditions than the ECMWF, which maintains the heat
over the East. The GEFS solution is preferred due to historical skill in the
region with respect to summertime excessive heat. Both the GEFS and ECWMF PETs
continue to indicate at least a 20% probability of daily maximum temperatures
exceeding the 85th percentile for a broader area of the central and eastern
CONUS for Jun 22-25, encompassing much of the Tennessee Valley and Michigan,
Mid-Atlantic,  and Northeast. Much of the West is also influenced by this broad
ridge, which is also indicated by the PETs having widespread 20% chances of
maximum temperatures exceeding the 85th percentile for most of the forecast
period. Therefore, a slight risk for excessive heat is posted for Jun 22-26 for
much of the western CONUS. Additionally, both the GEFS and ECMWF PETs indicate
at least a 40% probability of exceeding the 85th percentile for maximum
temperatures for the Wasatch Front of Utah and extending eastward into eastern
Nevada early in week-2, thus a moderate risk for excessive heat is designated
for this region, Jun 22-25.



In addition to the widespread potential for excessive heat across large
portions of the CONUS, ensemble solutions continue to depict an increase in
tropical moisture and convective activity over the southern Gulf of Mexico late
in week-1 and continuing into week-2. Todays solutions distribute the heaviest
precipitation across a broader area relative to yesterday, continuing the
increased potential for heavy precipitation across much of the Gulf Coast. The
GEFS and ECMWF PETs depict at least a 20% probability of 3-day precipitation
totals exceeding the 85th percentile and at least one inch for much of the Gulf
Coast, Jun 22-27, with higher probabilities and the potential for exceeding 2
inches across portions of the western Gulf. Todays model solutions are a
little slower to bring the heaviest precipitation onshore, therefore a moderate
risk for heavy precipitation is now posted for portions of the western and
central Gulf Coast for Jun 24-26, with a slight risk for heavy precipitation
extending further inland and including the rest of the Gulf Coast for Jun
22-27. Finally, abundant antecedent rainfall over much of eastern Texas has
resulted in most of the area reservoirs at or near capacity. Given the
potential for heavy rainfall during week-2, a risk for possible flooding and
flash flooding is also highlighted for the coastal plains of Texas and
Louisiana.



Ensemble solutions depict a clipper system potentially affecting the Northern
Tier early in the period, increasing the likelihood for heavy precipitation
across portions of the Upper Midwest at the outset of week-2. This is
well-indicated by the ECMWF (and to a lesser extent the GEFS) PETs, which
depict at least a 20% probability of 3-day precipitation totals exceeding the
85th percentile and 1 inch for Jun 22-24. Therefore a slight risk for heavy
precipitation is posted for portions of the Upper Midwest and Upper Mississippi
Valley for the dates indicated above. The synoptic pattern also favors enhanced
winds along the eastern Rockies and western Great Plains. The ECMWF and GEFS
both indicate high probabilities (>60%) of wind speeds to reach at least 10kt,
and the ECMWF wind-gust forecast depicts a near-certainty for gusts exceeding
20kt, early in the forecast period. A slight risk for high winds is posted for
portions of the eastern Rockies and western Plains for Jun 22-24 given these
enhanced wind signals.



Portions of the Mid-Atlantic from northern Virginia to southern New Jersey, the
Ohio Valley and Midwest have had substantial precipitation deficits over the
last month. With soil moisture deficits already in place, an extended heat wave
for the region predicted, and minimal precipitation anticipated through at
least the middle of week-2, these areas are highlighted in todays outlook for
the potential of rapid onset drought.

FORECASTER: Danny Barandiaran

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