776
FXUS01 KWBC 202000
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EDT WED SEP 20 2023
VALID 00Z THU SEP 21 2023 - 00Z SAT SEP 23 2023
...BELOW-NORMAL TEMPERATURES EXPECTED ACROSS MUCH OF THE WESTERN
U.S., WITH WIDESPREAD PRECIPITATION OVER THE NORTHERN
INTERMOUNTAIN WEST AND ROCKIES...
...INCREASING CHANCE FOR STRONG TO SEVERE STORMS AND HEAVY RAIN
OVER PORTIONS OF THE NORTHERN AND CENTRAL PLAINS ON FRIDAY...
...STRONG TO SEVERE THUNDERSTORMS AND HEAVY RAIN EXPECTED FOR
PORTIONS OF THE SOUTHERN PLAINS ON THURSDAY...
...GUSTY WINDS, HEAVY RAIN, AND HIGH SURF LIKELY FOR PORTIONS OF
THE SOUTHEAST AND SOUTHERN MID-ATLANTIC LATE THIS WEEK...
A DEEP UPPER-LEVEL LOW DEVELOPING OVER THE NORTHWEST TODAY IS
FORECAST TO SINK SLOWLY SOUTH OVER THE NEXT DAY BEFORE DRIFTING
EAST LATER IN THE WEEK. THIS SYSTEM IS EXPECTED TO BRING
WIDESPREAD PRECIPITATION TO THE INTERMOUNTAIN WEST AND NORTHERN
ROCKIES, WITH BELOW-NORMAL TEMPERATURES SPREADING ACROSS MUCH OF
THE WESTERN U.S. A FREEZE WATCH IS IN EFFECT FOR PORTIONS OF
NORTHWESTERN CALIFORNIA AND SOUTH-CENTRAL OREGON, WHERE WIDESPREAD
AREAS OF SUBFREEZING TEMPERATURES ARE POSSIBLE EAST OF THE
CASCADES TONIGHT INTO THURSDAY MORNING. A RED FLAG WARNING IS IN
EFFECT FARTHER TO THE SOUTHEAST, INCLUDING THE NORTHERN SACRAMENTO
VALLEY, WHERE GUSTY WINDS AND LOW HUMIDITY ARE EXPECTED BEGINNING
TONIGHT AND CONTINUING INTO THURSDAY.
OVER THE NORTHERN INTO THE CENTRAL PLAINS, SHOWERS AND
THUNDERSTORMS ARE FORECAST TO FOCUS NEAR A SLOW-MOVING FRONTAL
BOUNDARY THROUGH THE PERIOD, WITH THE THREAT FOR ORGANIZED HEAVIER
PRECIPITATION INCREASING BY FRIDAY AS THE SYSTEM IN THE WEST
BEGINS TO DRIFT EAST. ALSO INCREASING WILL BE THE THREAT FOR
SEVERE WEATHER, WITH SCATTERED STRONG TO SEVERE STORMS CAPABLE OF
LARGE HAIL, DAMAGING WINDS, AND PERHAPS A COUPLE OF TORNADOES
EXPECTED ACROSS PORTIONS OF THE CENTRAL PLAINS ON FRIDAY.
OVER THE SOUTHERN PLAINS, AN UPPER LEVEL DISTURBANCE INTERACTING
WITH A MOIST AIRMASS ALONG A SLOW-MOVING BOUNDARY WILL SUPPORT
SHOWERS AND THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS, WITH AN
INCREASED CHANCE FOR STRONG TO SEVERE STORMS AND HEAVY RAINFALL ON
THURSDAY ACROSS PORTIONS OF SOUTHERN OKLAHOMA AND NORTH TEXAS INTO
THE ARKLATEX REGION. DAMAGING WINDS AND HAIL, ALONG WITH HEAVY
RAINFALL RESULTING IN FLASH FLOODING ARE POSSIBLE ACROSS THIS AREA.
IN THE EAST, HIGH PRESSURE IS FORECAST TO PREVAIL ACROSS MUCH OF
THE REGION THROUGH LATE FRIDAY. THE PRIMARY EXCEPTION WILL BE
ALONG THE SOUTHEAST AND SOUTHERN MID-ATLANTIC COASTS. THIS REGION
WILL LIKELY BE IMPACTED BY A NON-TROPICAL LOW PRESSURE SYSTEM THAT
IS FORECAST TO DEVELOP EAST OF THE FLORIDA PENINSULA WITHIN THE
NEXT DAY OR TWO. THIS SYSTEM COULD ACQUIRE SOME SUBTROPICAL
CHARACTERISTICS AS IT TRACK NORTH ON FRIDAY. REGARDLESS OF
DEVELOPMENT, THIS LOW IS LIKELY TO BRING GUSTY WINDS, HEAVY RAIN,
AND HIGH SURF TO PORTIONS OF THE SOUTHEAST AND MID-ATLANTIC STATES
LATE THIS WEEK.
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