429
FXUS01 KWBC 221905
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
304 PM EDT SAT JUN 22 2024
VALID 00Z SUN JUN 23 2024 - 00Z TUE JUN 25 2024
...HEAT WAVE FOCUS SHIFTS FROM THE MIDWEST/OHIO VALLEY INTO THE
MID-ATLANTIC STATES THIS WEEKEND...
...EXCESSIVE RAINFALL AND SEVERE WEATHER CONCERNS ACROSS THE UPPER
GREAT LAKES/MISSISSIPPI VALLEY TONIGHT FOLLOWED BY NEW ENGLAND
SUNDAY...
...HEAT EXPANDS FROM WEST INTO PLAINS EARLY NEXT WEEK,
MONSOON-LIKE CONDITIONS FOR THE DESERT SOUTHWEST...
A HEAT WAVE WILL CONTINUE OVER MUCH OF THE EASTERN U.S. SOUTH OF A
QUASI-STATIONARY BOUNDARY AND UNDER THE INFLUENCE OF LONGWAVE
RIDGING ALOFT THIS WEEKEND. FORECAST LOW TEMPERATURES SATURDAY
WILL GENERALLY BE IN THE MID- TO UPPER 70S FROM THE
CENTRAL/SOUTHERN PLAINS TO THE EAST COAST. THESE TEMPERATURES
REMAIN THE MOST ANOMALOUS AND DANGEROUS FOR EARLY SUMMER OVER
PORTIONS OF THE MIDWEST/OHIO VALLEY EAST TO THE MID-ATLANTIC. A
POTENT UPPER-LEVEL SHORTWAVE WILL HELP TO FINALLY PUSH THE
BOUNDARY SOUTHWARD SUNDAY, BRINGING WELCOME RELIEF TO MUCH OF THE
MIDWEST/OHIO VALLEY, WHILE THE MID-ATLANTIC CONTINUES TO SIMMER.
NUMEROUS RECORD-TYING/BREAKING HIGHS ARE POSSIBLE. IN ADDITION,
OVERNIGHT LOW TEMPERATURES WILL REMAIN TO THE MID- AND EVEN UPPER
70S, PROVIDING LITTLE RELIEF FROM THE HEAT OVERNIGHT. THE
COMBINATION OF THIS HEAT COMING EARLY IN THE SUMMER SEASON AND
PERSISTING OVER SEVERAL DAYS INCREASES THE LEVEL OF HEAT STRESS
FOR THOSE WITHOUT RELIABLE AIR CONDITIONING.
WIDESPREAD SHOWERS AND THUNDERSTORMS WILL CONTINUE TO THE NORTH
ALONG THE QUASI-STATIONARY BOUNDARY DRAPED FROM NEW ENGLAND WEST
THROUGH THE GREAT LAKES AND INTO THE UPPER MISSISSIPPI VALLEY.
PLENTIFUL MOISTURE WILL INCREASE THE CHANCE FOR LOCALLY HEAVY
DOWNPOURS. THE HIGHEST CHANCE FOR POTENTIALLY SIGNIFICANT HEAVY
RAINFALL WILL BE ALONG THE BOUNDARY AHEAD OF AN UPPER-LEVEL WAVE
OVER PORTIONS OF THE UPPER GREAT LAKES/UPPER MISSISSIPPI VALLEY
TONIGHT. ONGOING ORGANIZED STORMS FROM OVERNIGHT FRIDAY AS WELL AS
THE RISK FOR MORE WIDESPREAD, ORGANIZED STORMS INTO THE DAY
SATURDAY HAS PROMPTED A MODERATE RISK OF EXCESSIVE RAINFALL (LEVEL
3/4) OVER SOUTHERN WISCONSIN AND NORTHEASTERN IOWA FOR THE THREAT
OF SCATTERED TO NUMEROUS INSTANCES OF FLASH FLOODING. A BROADER
SLIGHT RISK (LEVEL 2/4) COVERS THE REGION. IN ADDITION, A FEW
STORMS MAY BE SEVERE, WITH A SLIGHT RISK OF SEVERE WEATHER (LEVEL
2/5) ISSUED BY THE STORM PREDICTION CENTER FOR THE THREAT OF SOME
DAMAGING WINDS AND A FEW TORNADOES. A LOCALLY HIGHER THREAT FOR
HEAVIER DOWNPOURS WILL ALSO EXIST OVER SOUTHERN NEW ENGLAND, WITH
A SLIGHT RISK IN PLACE. THE NOTED MORE POTENT UPPER-LEVEL
SHORTWAVE ARRIVING SUNDAY WILL HELP TO PUSH THE BOUNDARY SOUTH AND
EASTWARD, BRINGING HIGHER STORM CHANCES MORE BROADLY ACROSS NEW
ENGLAND AND SOUTHWESTWARD THOUGH THE MID-ATLANTIC/OHIO
VALLEY/TENNESSEE VALLEY. STRONGER, VERY MOIST LOW-LEVEL FLOW
INTERACTING WITH THE BOUNDARY OVER NORTHERN NEW ENGLAND WILL BRING
THE GREATEST CHANCE FOR HEAVY DOWNPOURS AND SCATTERED FLASH
FLOODING, WITH ANOTHER SLIGHT RISK IN PLACE. SPC UPGRADED THEIR
SLIGHT RISK TO AN ENHANCED RISK OVER PARTS OF CENTRAL NEW
ENGLAND/MUCH OF NEW HAMPSHIRE AND VERMONT, WHERE DAMAGING WINDS
AND A FEW TORNADOES WILL ONCE AGAIN BE THE MAIN THREATS.
UPPER-LEVEL RIDGING WILL BEGIN TO BUILD OVER THE WESTERN AND THEN
CENTRAL U.S. FOLLOWING THE SHORTWAVE PASSAGE, BRINGING RISING
TEMPERATURES ACROSS THIS REGION AS WELL. THE FOCUS OVER THE
NORTHERN TIER WILL BEGIN TO SHIFT EASTWARD WITH THE RIDGE ON
SUNDAY, WITH COOLER HIGHS IN THE PACIFIC NORTHWEST BUT
TEMPERATURES SOARING INTO THE MID- AND UPPER 90S OVER MUCH OF THE
CENTRAL/NORTHERN HIGH PLAINS. CONDITIONS WILL REMAIN HOT FROM
CENTRAL TO SOUTHERN CALIFORNIA. TEMPERATURES WILL STILL BE HOT BUT
CLOSER TO AVERAGE FOR THE DESERT SOUTHWEST AS MONSOON-LIKE
CONDITIONS REMAIN OVER THE REGION. HIGHS ON SUNDAY AND MONDAY WILL
RANGE IN THE MID- TO UPPER 100S, WITH SCATTERED SHOWERS AND STORMS
BRINGING THE THREAT FOR SOME LOCALLY HEAVY DOWNPOURS AND AN
ISOLATED RISK FOR FLASH FLOODING, PARTICULARLY IN SLOT CANYONS.
ELSEWHERE, A PAIR OF WAVES OF LOW PRESSURE PASSING OVER PORTIONS
OF THE SOUTHEAST/FLORIDA AS WELL AS SOUTH TEXAS WILL BRING DAILY
SHOWER AND STORM CHANCES.
KEBEDE/PUTNAM
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