443
FXUS01 KWBC 010803
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT SAT JUL 01 2023
VALID 12Z SAT JUL 01 2023 - 12Z MON JUL 03 2023
...SEVERE THUNDERSTORMS AND AREAS OF HEAVY RAIN OVER THE MIDWEST
AND OHIO VALLEY TODAY ARE FORECAST TO REACH INTO THE NORTHEAST AND
MID-ATLANTIC ON SUNDAY...
...EXCESSIVE HEAT WARNINGS AND ADVISORIES ACROSS MUCH OF
CALIFORNIA INTO THE DESERT SOUTHWEST AS WELL AS THE DEEP SOUTH...
...AIR QUALITY ALERTS OVER PARTS OF THE MIDWEST, GREAT LAKES, AND
THE NORTHEAST, AND MID-ATLANTIC...
THE SLOW-MOVING WEATHER PATTERN RESPONSIBLE FOR THE SEVERE
THUNDERSTORMS AND AREAS OF HEAVY RAIN ACROSS THE CENTRAL PORTION
OF THE COUNTRY IS SHOWING SIGNS OF PROGRESSING EASTWARD TODAY AS
THE WESTERN U.S. UPPER-LEVEL TROUGH EXITS THE ROCKIES INTO THE
NORTHERN PLAINS. VERY ACTIVE DEVELOPMENT OF THUNDERSTORM
CLUSTERS ARE EXPECTED TO SHIFT FARTHER EAST ACROSS THE MIDWEST AND
THE OHIO VALLEY TODAY AHEAD OF A WARM FRONT, WHERE AN ENHANCED
RISK OF SEVERE THUNDERSTORMS IS ANTICIPATED BY THE STORM
PREDICTION CENTER. THESE THUNDERSTORMS WILL LIKELY CONTAIN HEAVY
DOWNPOURS, HAIL, DAMAGING WIND GUSTS, ALONG WITH THE POSSIBILITY
OF FLASH FLOODING. A LOW PRESSURE WAVE CURRENTLY DEVELOPING OVER
THE CENTRAL PLAINS IS FORECAST TO MOVE STEADILY NORTHEASTWARD INTO
THE MIDWEST BY SUNDAY MORNING, AND THEN ENTER THE LOWER GREAT
LAKES AND THE INTERIOR NORTHEAST BY MONDAY MORNING. SOME STRONG
THUNDERSTORMS ARE POSSIBLE ACROSS THE MID-ATLANTIC LATER TODAY OR
TONIGHT AHEAD OF THE LIFTING WARM FRONT. ANOTHER ROUND OF
SCATTERED THUNDERSTORMS CAN BE EXPECTED LATER ON SUNDAY ACROSS THE
MID-ATLANTIC AND THE CENTRAL APPALACHIANS AHEAD OF A COLD FRONT
WHILE THE MIDWEST AND THE OHIO VALLEY WILL BEGIN TO COOL DOWN AND
DRY OUT BEHIND THE FRONT. NEW ENGLAND APPEARS TO BE THE WETTEST
WITH THIS SYSTEM THROUGH THIS WEEKEND INTO MONDAY. GIVEN THE
LOCALLY HEAVY RAINFALL THAT HAS OCCURRED OVER THE PREVIOUS WEEK, A
MARGINAL RISK FOR EXCESSIVE RAINFALL IS IN EFFECT FROM THE OHIO
VALLEY INTO THE NORTHEAST ON SUNDAY INTO EARLY MONDAY.
MEANWHILE, THE SAME UPPER TROUGH EJECTING INTO THE CENTRAL U.S.
WILL BEGIN TO ERODE THE UPPER RIDGE THAT HAS BEEN RESPONSIBLE FOR
THE PROLONGED HEAT WAVE ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY. AS THE UPPER RIDGE WEAKENS, THE HIGHEST
TEMPERATURES AND HEAT INDICES WILL SLOWLY TREND DOWN, THOUGH
SWELTERING HEAT IS ANTICIPATED TO CONTINUE ACROSS THE SOUTHEAST,
PARTICULARLY ALONG THE GULF COAST. SEVERAL CITIES ACROSS THE LOWER
MISSISSIPPI VALLEY AND SOUTHEAST ARE EXPECTED TO BREAK THEIR DAILY
WARMEST NIGHTTIME LOW RECORDS THROUGH THE WEEKEND. HEAT-RELATED
DANGER REMAINS ELEVATED DUE TO THE LONGEVITY OF THIS HEAT WAVE. AS
THE RIDGE MOVES ACROSS THE SOUTH-CENTRAL PLAINS, HEAT WILL BUILD
ALONG THE WEST COAST AND REACH PORTIONS OF THE NORTHERN PLAINS BY
SUNDAY. AFTERNOON TEMPERATURES IN THE INTERIOR VALLEYS OF
CALIFORNIA MAY CLIMB OVER 100F TO NEAR 110F AT THE HOTTEST
LOCATIONS ON SATURDAY. THE DESERT SOUTHWEST WILL SEE TEMPERATURES
CLIMB WELL INTO THE 110S. THE RISK OF HEAT-RELATED ILLNESSES WILL
BE HIGH THROUGH THE WEEKEND.
IN ADDITION TO THE HEAT AND THE SEVERE STORMS, CANADIAN WILDFIRE
SMOKE IS EXPECTED TO CONTINUE IMPACTING PORTIONS OF GREAT LAKES
AND EAST COAST OVER THE NEXT FEW DAYS. HOWEVER, AIR QUALITY IS
EXPECTED TO SLOWLY IMPROVE DUE TO A COMBINATION OF THUNDERSTORM
ACTIVITY AND DISPERSION OF THE SMOKE AS WE HEAD INTO THE WEEKEND.
KONG/GENZ
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