860
FXUS01 KWBC 190747
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
346 AM EDT SAT AUG 19 2023
VALID 12Z SAT AUG 19 2023 - 12Z MON AUG 21 2023
...CATASTROPHIC AND LIFE-THREATENING FLOODING LIKELY OVER PORTIONS
OF THE SOUTHWEST...
..DANGEROUS HEAT EXPANDING OVER THE CENTRAL U.S..
HURRICANE HILARY HAS NOW TURNED NORTH-NORTHWESTWARD AND IS
FORECAST TO TRACK NEAR BAJA CALIFORNIA BEFORE MAKING LANDFALL NEAR
THE U.S.-MEXICO BORDER LATER THIS WEEKEND. HEAVY RAINFALL
ASSOCIATED WITH THE SYSTEM IS FORECAST TO DEVELOP ACROSS THE
SOUTHWESTERN U.S. TODAY, WELL IN ADVANCE OF THE STORM'S CENTER,
AND CONTINUE THROUGH THE WEEKEND, WITH THE HEAVIEST AMOUNTS
EXPECTED ON SUNDAY. HIGHLY ANOMALOUS MOISTURE TRANSPORT INTO THE
REGION WILL SUPPORT RAINFALL AMOUNTS EXCEEDING THE AVERAGE ANNUAL
TOTALS FOR SOME LOCATIONS IN THE SOUTHWEST. FLASH, URBAN, AND
ARROYO FLOODING IS EXPECTED, WITH DANGEROUS AND LOCALLY
CATASTROPHIC IMPACTS LIKELY. IN ADDITION TO FLOODING RAINS,
HILARY IS FORECAST TO BRING TROPICAL STORM CONDITIONS TO PORTIONS
OF SOUTHERN CALIFORNIA ON SUNDAY. LARGE SWELLS WILL AFFECT
PORTIONS OF SOUTHERN CALIFORNIA OVER THE NEXT FEW DAYS. THESE
SWELLS ARE LIKELY TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS. WIDESPREAD CLOUD COVER WILL KEEP TEMPERATURES BELOW
AVERAGE, WITH UNSEASONABLY COOL TEMPERATURES FORECAST TO EXPAND
NORTHWARD FROM SOUTHERN CALIFORNIA AND WESTERN ARIZONA INTO THE
SIERRA NEVADA AND THE GREAT BASIN THROUGH THE WEEKEND.
IN CONTRAST TO THE TEMPERATURES IN THE WEST, DANGEROUS HEAT WILL
CONTINUE TO INTENSIFY AND EXPAND, WITH WELL ABOVE-NORMAL TO
RECORD-BREAKING TEMPERATURES FORECAST ACROSS THE PLAINS AND LOWER
MISSISSIPPI VALLEY TODAY. THE HEAT WAVE WILL CONTINUE TO EXPAND
ON SUNDAY TO INCLUDE MORE OF THE MIDWEST ON SUNDAY. THIS WEEKEND,
SOME LOCATIONS IN THE MIDWEST MAY EXPERIENCE THEIR HOTTEST DAY OF
THE YEAR. THE PROLONGED NATURE OF THE HEAT WAVE, COMBINED WITH
VERY WARM OVERNIGHT TEMPERATURES, WILL LIMIT RELIEF FROM THE
OPPRESSIVE DAYTIME TEMPERATURES AND COMPOUND THE OVERALL HEAT
IMPACTS.
A RELATIVELY QUIET PERIOD IS EXPECTED FOR MUCH OF THE EASTERN
U.S., WITH SHOWER AND THUNDERSTORMS CONFINED MAINLY TO FLORIDA AND
THE SOUTHEAST COAST. AFTER ANOTHER DAY OF SEASONAL TO
BELOW-AVERAGE TEMPERATURES TODAY, SUMMER HEAT IS FORECAST TO
RETURN TO MUCH OF THE NORTHEAST AND MID-ATLANTIC STATES ON SUNDAY.
PEREIRA
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