171
FXUS01 KWBC 200803
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EST MON NOV 20 2023
VALID 12Z MON NOV 20 2023 - 12Z WED NOV 22 2023
...ENHANCED RISK OF SEVERE WEATHER ACROSS THE DEEP SOUTH LATER
TODAY/TONIGHT AHEAD OF A LOW PRESSURE SYSTEM...
...LOCALLY HEAVY RAIN AND POSSIBLY STRONG THUNDERSTORMS ACROSS THE
MID-MISSISSIPPI VALLEY TODAY AND THEN ACROSS THE INTERIOR
MID-ATLANTIC TUESDAY INTO EARLY WEDNESDAY...
...HIGH-ELEVATION SNOWS AND LOWER ELEVATION RAIN ACROSS THE
CENTRAL AND SOUTHERN ROCKIES/HIGH PLAINS EXPECTED TO TAPER OFF
TONIGHT...
...SANTA ANA WINDS DEVELOP OVER SOUTHERN CALIFORNIA DURING THE
NEXT COUPLE OF DAYS...
A LOW PRESSURE SYSTEM CURRENTLY DEVELOPING OVER THE MID-SECTION OF
THE COUNTRY WILL SEND A WAVE OF INCLEMENT WEATHER THROUGH THE
EASTERN TWO-THIRDS OF THE COUNTRY THROUGH THE NEXT COUPLE OF DAYS.
THE MOST SIGNIFICANT BOUT OF INCLEMENT WEATHER APPEARS TO BE
LATER TODAY INTO TONIGHT FROM EASTERN TEXAS TO THE LOWER
MISSISSIPPI VALLEY WHERE AN OUTBREAK OF SEVERE THUNDERSTORMS ARE
POSSIBLE AS A DYNAMIC COLD FRONT ASSOCIATED WITH THE INTENSIFYING
LOW PRESSURE SYSTEM SWEEPS ACROSS. SOME OF THE THUNDERSTORMS
COULD CONTAIN HIGH WINDS AND TORNADOES, TOGETHER WITH HEAVY
DOWNPOURS AND HAIL. THE SPEED OF THE SYSTEM IS EXPECTED TO LIMIT
THE THREAT OF FLASH FLOODING FOR THESE AREAS.
BY TUESDAY, THE CENTER OF THE LOW PRESSURE SYSTEM IS FORECAST TO
REACH THE LOWER GREAT LAKES BRINGING WIDESPREAD RAIN WITH SOME
EMBEDDED THUNDERSTORMS FROM THE MIDWEST TO THE LOWER GREAT LAKES
AND OHIO VALLEY, AND QUICKLY TOWARD NEW ENGLAND TUESDAY NIGHT.
TEMPERATURES WILL PROBABLY BE COLD ENOUGH TO SUPPORT SOME WET SNOW
EARLY ON TUESDAY OVER THE UPPER MIDWEST, REACHING EASTWARD INTO
INTERIOR NEW ENGLAND BY TUESDAY NIGHT ALONG WITH SOME FREEZING
RAIN POSSIBLE. MEANWHILE, SOME STRONG THUNDERSTORMS CAN BE
EXPECTED TO TRACK ACROSS THE TENNESSEE VALLEY/INTERIOR SOUTHEAST
EARLY TUESDAY, FOLLOWED BY THE SOUTHERN APPALACHIANS AND INTO
INTERIOR MID-ATLANTIC BY TUESDAY NIGHT INTO EARLY WEDNESDAY AS A
LOW PRESSURE WAVE FORMS AND TRACKS ALONG A WARM FRONT. COLDER AIR
WILL THEN BE USHERED ACROSS THE CENTRAL AND SOUTHERN PLAINS BEHIND
THE LOW PRESSURE SYSTEM. SOME HIGH-ELEVATION SNOWS AND LOWER
ELEVATION RAIN ARE EXPECTED ACROSS THE CENTRAL AND SOUTHERN
ROCKIES/HIGH PLAINS TODAY BUT THEY ARE EXPECTED TO TAPER OFF
TONIGHT BEHIND THE INTENSIFYING SYSTEM.
A LARGE DOME OF HIGH PRESSURE BUILDING BEHIND DEPARTING LOW
PRESSURE SYSTEM WILL THEN SETTLE ACROSS MUCH OF THE WESTERN U.S
FOR THE NEXT FEW DAYS. TIGHT PRESSURE GRADIENT AROUND THE HIGH
WILL PROMOTE SANTA ANA WINDS ESPECIALLY ACROSS SOUTHERN CALIFORNIA.
HIGH TEMPERATURES TODAY AND TUESDAY WILL REMAIN BELOW AVERAGE FROM
NEW ENGLAND SOUTH INTO THE MID-ATLANTIC FOLLOWING A FRONTAL
PASSAGE, WITH 30S AND 40S FOR NEW ENGLAND AND 50S INTO THE
MID-ATLANTIC. IN THE SOUTH, CONDITIONS WILL BE UNSEASONABLY WARM
AHEAD OF THE APPROACHING FRONTAL SYSTEM, WITH 70S AND EVEN SOME
80S ALONG THE GULF COAST. THE DIGGING TROUGH OVER THE CENTRAL U.S.
WILL BRING COOLER AND BELOW AVERAGE TEMPERATURES SOUTH INTO THE
SOUTHERN PLAINS AND TEXAS BY TUESDAY, WITH WIDESPREAD 50S
EXPECTED. HIGHS WILL BE MORE SEASONABLY COOL FURTHER NORTH ACROSS
THE NORTHERN PLAINS INTO THE GREAT LAKES WITH MAINLY 40S FORECAST.
TEMPERATURES WILL MODERATE IN THE WEST AFTER A COOLER WEEKEND,
WITH 40S AND 50S FOR THE GREAT BASIN/ROCKIES, 50S AND 60S FOR THE
PACIFIC NORTHWEST AND NORTHERN CALIFORNIA, AND 70S FOR SOUTHERN
CALIFORNIA AND THE DESERT SOUTHWEST.
KONG/PUTNAM
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