654
FXUS01 KWBC 131953
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
353 PM EDT SUN AUG 13 2023
VALID 00Z MON AUG 14 2023 - 00Z WED AUG 16 2023
...FLASH FLOODING AND SEVERE THUNDERSTORMS POSSIBLE FOR PORTIONS
OF THE PLAINS/MISSISSIPPI VALLEY SUNDAY, SHIFTING TO THE GREAT
LAKES/OHIO VALLEY/MID-ATLANTIC MONDAY...
...THE SOUTH CONTINUES ITS DANGEROUS HEATWAVE WHILE ANOTHER HEAT
WAVE BEGINS ACROSS THE PACIFIC NORTHWEST SUNDAY...
...MONSOONAL SHOWERS CONTINUE ACROSS THE FOUR CORNERS REGION WITH
SOME LOCALLY HEAVY DOWNPOURS POSSIBLE...
THE NORTHERN STREAM WILL CONTINUE TO BE ACTIVE AND UNSETTLED AS AS
PAIR OF FRONTAL BOUNDARIES TRIGGER NUMEROUS SHOWERS AND
THUNDERSTORMS FROM THE PLAINS EASTWARD. THESES STORMS HAVE
POTENTIAL TO BE QUITE STRONG, AS SUFFICIENT DEEP LAYER SHEAR WILL
BE IN PLACE FOR SOME ORGANIZED SEVERE STORMS CAPABLE OF DAMAGING
WINDS, A FEW TORNADOES, AND LARGE HAIL. THEY MAY ALSO DUMP SEVERAL
INCHES OF RAIN. MOISTURE POOLING BETWEEN THE BOUNDARIES FROM
PORTIONS OF THE CENTRAL/SOUTHERN PLAINS INTO THE MIDDLE
MISSISSIPPI VALLEY WILL HELP PROMOTE EFFICIENT RAINFALL RATES WITH
THE PROSPECT OF STORMS MOVING PARALLEL TO THE FRONTS REPEATEDLY
OVER THE SAME REGION HEIGHTENING THE RISK FOR SEVERAL INCHES OF
RAINFALL. THE STORM PREDICTION CENTER HAS AN ENHANCED RISK IN
PLACE OVER THE MISSOURI/ARKANSAS OZARKS REGION WITH A BROADER
SLIGHT RISK SPANNING FROM THE OKLAHOMA/TEXAS PANHANDLES TO THE
TENNESSEE VALLEY. ADDITIONALLY, WPC HAS A MODERATE RISK FOR
EXCESSIVE RAINFALL OVER THE OZARKS REGION AND A SLIGHT FOR MUCH OF
THE SAME AREA AS SPC. THE THREAT AREA WILL SHIFT TO THE GREAT
LAKES, OHIO/TENNESSEE VALLEYS, MID-ATLANTIC AND THE NORTHEAST
MONDAY AND TUESDAY. BEHIND THE COLD FRONT, COOLER AIR WILL
INFILTRATE THE NORTHERN PLAINS AND UPPER MIDWEST YIELDING DAILY
MAXIMUMS TO RANGE FROM THE UPPER 60S TO LOWER 70S AND WILL SPREAD
EASTWARD INTO THE MIDWEST; MID 70S TO LOWER 80S CAN BE EXPECTED
FOR PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS. HIGHS WILL BE
CLOSER TO AND ABOVE SUMMERTIME AVERAGES AHEAD OF THE FRONT, WITH
UPPER 70S AND LOW 80S FOR NEW ENGLAND AND MID-80S TO LOW 90S FOR
THE MID-ATLANTIC.
IN CONTRAST, THE PROLONGED HOT SPELL WILL KEEP DANGEROUS
TEMPERATURES IN PLACE FOR MUCH OF THE SOUTH INTO EARLY NEXT WEEK
THANKS TO THE WELL ANCHORED UPPER RIDGE. WIDESPREAD HEAT-RELATED
ADVISORIES AND WARNINGS SPAN FROM FLORIDA NORTH TO THE CAROLINAS
AND WEST TO TEXAS/OKLAHOMA; WITH THE MOST EXCESSIVE HEAT FOCUSING
OVER TEXAS AND INTO THE LOWER MISSISSIPPI VALLEY. DAILY HIGH
TEMPERATURES ARE FORECAST TO RANGE FROM THE MID-90S IN FLORIDA AND
THE CAROLINAS, THE UPPER 90S INTO PORTIONS OF THE SOUTHEAST, THE
LOW 100S IN OKLAHOMA AND THE LOWER MISSISSIPPI VALLEY, AND THE MID
100S INTO PORTIONS OF TEXAS. THESE TEMPERATURES WHEN COMBINED WITH
HIGH HUMIDITY WILL ALLOW FOR HEAT INDICES AS HIGH AS 110 TO 120F
FOR MANY LOCATIONS. NUMEROUS RECORD-TYING/BREAKING HIGHS ARE
FORECAST BOTH DAYS, WITH SIMILARLY RECORD-LEVEL WARM LOW
TEMPERATURES IN THE UPPER 70S TO LOW 80S PROVIDING LITTLE RELIEF
FROM THE HEAT OVERNIGHT. SOME MODERATION OF THE HEAT IS EXPECTED
FOR NORTHERN PORTIONS OF THE REGION BY THE MIDDLE OF THIS UPCOMING
WEEK AS COOLER AIR FOLLOWS THE SOUTHWARD MOVING COLD FRONT CUTTING
ACROSS THE COUNTRY, STARTING WITH THE NOTED PORTIONS OF THE
SOUTHERN PLAINS MONDAY.
A HEATWAVE IS BEGINNING TO BUILD IN TODAY OVER THE PACIFIC
NORTHWEST IN RELATION TO THE STRONG RIDGE OF HIGH PRESSURE
OVERHEAD. TEMPERATURES WILL NEARING THE 100 MARK TODAY WITHIN THE
INTERIOR VALLEYS WEST OF THE CASCADES IN OREGON 100S AND WILL
FURTHER INTENSIFY AND EXPAND ACROSS THE REGION MONDAY. MAXIMUM
TEMPERATURES WILL RANGE FROM UPPER 80S TO LOW 90S AROUND PUGET
SOUND, THE UPPER 90S TO LOW 100S EAST OF THE CASCADES, AND THE
MID-100S TO POTENTIALLY OVER 110 DEGREES FOR THE INTERIOR WEST OF
THE CASCADES. NUMEROUS NEAR RECORD-TYING/BREAKING HIGHS ARE
POSSIBLE HERE AS WELL. THESE TEMPERATURES COMBINED WITH THE
DURATION OF HEAT, EXPECTED TO CONTINUE THROUGH THIS WEEK, WILL
INCREASINGLY POSE A HEIGHTENED HEALTH RISK, ESPECIALLY FOR THOSE
WITHOUT ADEQUATE AIR CONDITIONING.
DAILY ROUNDS OF THUNDERSTORM ACTIVITY CAN BE EXPECTED ACROSS THE
FOUR CORNERS REGION THANKS TO MONSOONAL MOISTURE AND A LINGERING
FRONTAL BOUNDARY NEAR THE REGION. ANY OF THESE STORMS MAY HAVE THE
POTENTIAL TO PRODUCE HEAVY DOWNPOURS WHICH BRINGS AN ISOLATED
THREAT FOR FLASH FLOODING. DAILY HIGHS WILL BE NEAR SEASONAL
NORMAL WITH 70S IN PROXIMITY OF THE CALIFORNIA COAST, LOW TO
MID-90S FOR THE GREAT BASIN, UPPER 90S TO LOW 100S FOR THE
INTERIOR CALIFORNIA VALLEYS, AND 100S FOR THE DESERT SOUTHWEST.
WITH COOLER, POST-FRONTAL AIR FILTERING SOUTH INTO THE CENTRAL
U.S., PORTIONS OF THE CENTRAL/SOUTHERN HIGH PLAINS/ROCKIES WILL
HAVE SOME COOLER HIGHS THAN POINT WEST; MAINLY IN THE UPPER 70S TO
LOW 80S.
CAMPBELL
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