415
FXUS21 KWNC 031908
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT June 03 2024

SYNOPSIS: Mid-level high pressure predicted over the western contiguous U.S.
(CONUS) is predicted to slightly weaken toward the end of week-1 with slight
rebuilding at the beginning of week-2 before shifting eastward and gradually
weakening by the latter half of week-2. This pattern translates to some
possible resurgence of excessive heat across the Interior West and southern
Texas during the earlier half of week-2 after a slight decrease in heat signals
at the end of week-1. Intensification of a thermal low over the Sonoran Desert
increases chances for periods of high winds from the middle to end of week-2
across portions of the Central Great Basin and Southwest.

HAZARDS

Moderate risk of excessive heat for parts of the Central Valley of California,
Nevada, and Desert Southwest, Tue-Wed, Jun 11-12.

Slight risk of excessive heat across parts of the Interior West and western and
southern Texas, Tue-Fri, Jun 11-14.

Slight risk of periods of high winds for portions of the Central Great Basin
and Southwest, Thu-Mon, Jun 13-17.

Rapid onset drought risk across parts of southern Texas.

DETAILED SUMMARY

FOR THURSDAY JUNE 06 - MONDAY JUNE 10:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR TUESDAY JUNE 11 - MONDAY JUNE 17: After a brief waning in the strength of
the mid-level ridge across the western CONUS at the end of week-1, multiple
models indicate a slight increase in amplification during the beginning of
week-2 before shifting eastward, and gradually weakening by the latter half of
the period. This pattern translates to a potential resurgence of heat across
parts of the West and south-central CONUS at the beginning to middle of week-2
with decreasing heat signals thereafter. The ECENS ensemble mean indicates
greater 500 hPa height departures across the western CONUS compared to the GEFS
and CMCE counterparts resulting in the ECENS tools having a greater heat signal
than the GEFS and CMCE.



A slight risk of excessive heat is highlighted across parts of the Interior
West and western and southern Texas, Jun 11-14, where the GEFS, ECENS, and
Canadian Probabilistic Extremes Tools (PETs) show a 20-40% chance of maximum
temperatures exceeding the 85th percentile climatologically and 90 deg F across
the Northwest and greater than 95 deg F further south. An embedded moderate
risk area is designated for parts of the Central Valley of California, Nevada,
and Desert Southwest, June 11-12, primarily based on where the ECENS PET
indicates at least a 40% chance of exceeding hazardous criteria (GEFS PET
limits probabilities to 30-40% and CMCE PET 20-30%). The greatest heat index
values are anticipated across Texas, where values are expected to exceed 105
deg F. The National Blend of Models (NBM) shows possible near record
temperatures for parts of northern California and Texas June 12-13.



Thermal low pressure over the Sonoran Desert is predicted to strengthen from
the middle to the end of the period, supporting a slight risk of high winds for
portions of the Central Great Basin and Southwest, June 13-17. The GEFS and
ECENS PETs indicate at least a 20% chance of wind speeds exceeding the 85th
percentile and 20 mph. Anticipated hot, dry, and windy conditions may increase
wildfire risk across the Southwest especially where the National Interagency
Fire Center (NIFC) shows moderate risk of significant fire potential by the end
of week-1.



Above normal precipitation forecast for the week-2 period supports removal of
the rapid onset drought risk for Florida. Over southern Texas, precipitation
deficits over the past 30- and 60-days, high rates of evapotranspiration (ET),
and the continued forecast of high heat and subnormal precipitation supports
possible rapid onset drought, albeit some northeastern coastal portions have
been eliminated in todays outlook due to anticipated week-2 precipitation.



Mid-level troughing anticipated over the eastern CONUS combined with some
models showing the potential for tropical disturbances may increase the
potential for heavy rainfall across parts of Florida, especially June 12-14.
However, at this time there are significant model differences precluding the
designation of any associated heavy precipitation hazards at this time but will
be monitored in the upcoming days.

FORECASTER: Melissa Ou

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