343
FXUS01 KWBC 182024
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
423 PM EDT FRI AUG 18 2023
VALID 00Z SAT AUG 19 2023 - 00Z MON AUG 21 2023
...HURRICANE HILARY TO BRING HEAVY RAINFALL AND FLASH FLOODING TO
PARTS OF THE SOUTHWEST THIS WEEKEND...
...CRITICAL FIRE CONDITIONS EXPECTED FROM THE NORTHWEST TO THE
NORTHERN HIGH PLAINS TONIGHT...
..DANGEROUS HEAT REDEVELOPING OVER THE CENTRAL U.S..
SHORTWAVE ENERGY OUT AHEAD OF HURRICANE HILARY WILL GENERATE
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE DESERT SOUTHWEST,
SOUTHERN SIERRA NEVADA AND CENTRAL GREAT BASIN TONIGHT. THE
HEAVIEST RAINFALL (~1 INCH) WILL OCCUR ALONG THE U.S. MEXICO
BORDER, BUT RAIN-SENSITIVE AREAS IN THE SOUTHWEST AND FOUR CORNERS
REGIONS COULD EXPERIENCE FLASH FLOODING FROM RELATIVELY LIGHTER
AMOUNTS. A SLIGHT RISK OF EXCESSIVE RAINFALL LEADING TO FLASH
FLOODING IS IN EFFECT ACROSS SOUTHEASTERN CALIFORNIA, SOUTHERN
NEVADA/UTAH AND NORTHWESTERN ARIZONA THROUGH TONIGHT. DRY
CONDITIONS AND STRONG WINDS BENEATH THE BASE OF AN ENERGIZED UPPER
TROUGH WILL SUPPORT TWO TARGETED CRITICAL FIRE WEATHER RISK AREAS
OVER PARTS OF EASTERN WASHINGTON/NORTHERN OREGON AND NORTHERN
MONTANA, RESPECTIVELY TONIGHT.
RAIN AND THUNDERSTORM ACTIVITY ASSOCIATED WITH HILARY BEGIN TO
RAMP UP ACROSS THE DESERT SOUTHWEST ON SATURDAY. A MODERATE RISK
OF EXCESSIVE RAINFALL IN EFFECT FOR MUCH OF SOUTHEASTERN
CALIFORNIA, PARTS OF WESTERN ARIZONA AND SOUTHERN NEVADA ON
SATURDAY DUE TO POTENTIAL FLASH FLOODING CONCERNS OVER SENSITIVE
BURN SCARS, ELEVATED TERRAIN AND SLOT CANYONS. WINDS AND RAIN
RATES WILL INTENSIFY MORE ACROSS CALIFORNIA AND THE SOUTHWEST
EARLY SUNDAY MORNING INTO MONDAY, WHEN THE BRUNT OF HILARY'S
IMPACTS WILL BE FELT. RAINFALL AMOUNTS OF 3 TO 6 INCHES, WITH
ISOLATED AMOUNTS OF 10 INCHES, ARE EXPECTED ACROSS PORTIONS OF
SOUTHERN CALIFORNIA AND SOUTHERN NEVADA. DANGEROUS TO LOCALLY
CATASTROPHIC FLOODING WILL BE POSSIBLE. ELSEWHERE ACROSS PORTION
OF THE WESTERN UNITED STATES, RAINFALL TOTALS OF 1 TO 3 INCHES ARE
EXPECTED, RESULTING IN LOCALIZED FLASH FLOODING. THE DELUGE OF
RAINFALL COULD SET RECORDS WHEN ALL IS SAID AND DONE. RECORD LOW
MAXIMUM TEMPERATURES ARE ALSO LIKELY ACROSS THE DESERT SOUTHWEST
ON SUNDAY AND MONDAY DUE TO THE ABNORMAL LACK OF SUNSHINE CAUSED
BY HILARY.
DANGEROUS HEAT WILL CONTINUE TO INTENSIFY AND EXPAND INTO THE
PLAINS STATES THROUGH SATURDAY, WITH NUMEROUS DAILY HIGH
TEMPERATURE RECORDS EXPECTED, ESPECIALLY IN THE CENTRAL PLAINS AND
TEXAS. THE HEAT WAVE WILL FURTHER EXPAND ON SUNDAY AND EARLY NEXT
WEEK TO INCLUDE MUCH OF THE CENTRAL AND SOUTHEAST U.S.. SOME
LOCATIONS IN THE MIDWEST MAY SEE THEIR HOTTEST DAY OF THE YEAR SO
FAR THIS WEEKEND, AND PORTIONS OF THE SOUTH-CENTRAL U.S. AND GULF
COAST MAY FURTHER EXTEND THEIR RECORD NUMBER OF HOURS WITH A HEAT
INDEX READING OF AT LEAST 110F DEGREES. THE PROLONGED NATURE OF
THE HEAT WAVE COMBINED WITH VERY WARM OVERNIGHT TEMPERATURES WILL
LIMIT RELIEF FROM THE OPPRESSIVE DAYTIME HEAT AND COMPOUND OVERALL
HEAT IMPACTS.
KEBEDE
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