793
FXUS01 KWBC 260817
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
412 AM EDT WED JUN 26 2024
VALID 12Z WED JUN 26 2024 - 12Z FRI JUN 28 2024
...HEAT WAVE CONTINUES FOR THE SOUTHERN PLAINS, LOWER MISSISSIPPI
VALLEY, AND SOUTHEAST...
..MONSOON-LIKE CONDITIONS PERSIST FOR THE FOUR CORNERS REGION
...SEVERE STORMS AND FLASH FLOODING EXPECTED OVER THE
NORTHERN/CENTRAL PLAINS THURSDAY...
A HEATWAVE PERSISTS OVER MUCH OF THE SOUTHERN TIER OF THE COUNTRY
AS A STUBBORN UPPER-LEVEL HIGH LINGERS OVER THE
SOUTHWESTERN/SOUTH-CENTRAL U.S. HIGHS ARE FORECAST IN THE MID- TO
UPPER 90S WEDNESDAY ACROSS THE REGION, WITH LOW 100S EXPECTED OVER
PORTIONS OF SOUTH CAROLINA AND GEORGIA AS WELL AS THE SOUTHERN
HIGH PLAINS. HUMID CONDITIONS WILL LEAD TO HEAT INDEX VALUES IN
THE MID- TO UPPER 100S OUTSIDE OF DRIER AREAS IN THE SOUTHERN HIGH
PLAINS, WITH WIDESPREAD HEAT ADVISORIES IN PLACE. THE MOST INTENSE
HEAT WILL BE OVER PORTIONS OF CENTRAL/SOUTHERN OKLAHOMA AND
NORTHWEST TEXAS, WHERE AN EXCESSIVE HEAT WARNING IS IN PLACE FOR
HEAT INDICES AS HIGH AS 112. IN ADDITION, OVERNIGHT LOWS IN THE
MID- TO UPPER 70S WILL PROVIDE LITTLE RELIEF FROM THE HEAT
OVERNIGHT. THE EARLY ARRIVAL AND PERSISTENCE OF THE INTENSE HEAT
WILL LEAD TO MORE HEAT STRESS THAN NORMAL GIVEN SIMILAR CONDITIONS
LATER IN THE SUMMER, ESPECIALLY FOR THOSE WITHOUT RELIABLE AIR
CONDITIONING. PORTIONS OF THE LOWER MISSISSIPPI VALLEY AND
SOUTHEAST WILL SEE SOME RELIEF ON THURSDAY FOLLOWING A COLD FRONT
PASSAGE, WITH HIGHS A FEW DEGREES LOWER AND SLIGHTLY LESS HUMID
CONDITIONS. UNFORTUNATELY, CONDITIONS WILL REMAIN DANGEROUSLY HOT
OVER PORTIONS OF GEORGIA/SOUTH CAROLINA AND THE SOUTHERN PLAINS.
SOME HEAT WILL ALSO SPREAD BACK INTO THE MID-ATLANTIC WEDNESDAY
WITH HIGHS IN THE MID- TO UPPER 90S. A COLD FRONT PASSAGE WILL
BRING TEMPERATURES BACK DOWN A BIT INTO THE 80S TO LOW 90S
THURSDAY.
FURTHER TO THE WEST, MONSOON-LIKE CONDITIONS WILL PERSIST UNDER
THE UPPER-LEVEL HIGH OVER THE FOUR CORNERS REGION GIVEN A
CONTINUED INFLUX OF ANOMALOUSLY HIGH MOISTURE. DAILY SCATTERED
THUNDERSTORMS MAY PRODUCE SOME LOCALLY HEAVY DOWNPOURS, WITH SOME
SCATTERED INSTANCES OF FLASH FLOODING POSSIBLE, ESPECIALLY FOR
TERRAIN SENSITIVE AREAS SUCH AS BURN SCARS AND SLOT CANYONS. THE
GREATEST STORM COVERAGE ON WEDNESDAY IS EXPECTED OVER PORTIONS OF
NORTHERN NEW MEXICO, WHERE A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2/4) IS IN PLACE. AN APPROACHING UPPER-LEVEL SYSTEM TO THE
NORTH WILL HELP TO BREAK DOWN THE UPPER-LEVEL HIGH AND BRING MORE
ZONAL UPPER-LEVEL FLOW ACROSS THE REGION, EXPANDING HIGHER STORM
CHANCES NORTHWARD ON THURSDAY WITH A SLIGHT RISK STRETCHING FROM
NORTHERN NEW MEXICO NORTH THROUGH WESTERN COLORADO.
STORM CHANCES WILL INCREASE OVER PORTIONS OF THE PLAINS AND
MIDWEST AHEAD OF AN APPROACHING UPPER-LEVEL SYSTEM ON THURSDAY.
FIRST, ON WEDNESDAY, SOME SEVERE THUNDERSTORMS WILL BE POSSIBLE
OVER THE CENTRAL HIGH PLAINS AS UPSLOPE FLOW BRINGS SOME
INCREASING MOISTURE AND LEADS TO A BIT OF INSTABILITY. THE STORM
PREDICTION CENTER HAS OUTLINED A SLIGHT RISK (LEVEL 2/5) OF SEVERE
WEATHER FOR THE THREAT OF SOME DAMAGING WINDS AND LARGE HAIL.
THEN, AS THE UPPER-LEVEL SYSTEM APPROACHES, LEE CYCLOGENESIS IN
THE NORTHERN HIGH PLAINS WILL LEAD TO A STRENGTHENING LOW
PRESSURE/FRONTAL SYSTEM, EVENTUALLY MOVING EASTWARD INTO THE
PLAINS THROUGH THE DAY THURSDAY. ENHANCED SOUTHERLY FLOW AHEAD OF
THE SYSTEM WILL BRING MOISTURE NORTHWARD AND LEAD TO A BROAD AREA
OF SCATTERED THUNDERSTORM DEVELOPMENT OVER THE NORTHERN HIGH
PLAINS SOUTHWARD THROUGH THE CENTRAL PLAINS. THE STORM PREDICTION
CENTER HAS ISSUED A SLIGHT RISK FOR THIS REGION FOR THE THREAT OF
LARGE HAIL AND DAMAGING WINDS, PERHAPS SIGNIFICANT OVER THE
NORTHERN HIGH PLAINS, AS WELL AS A COUPLE ISOLATED TORNADOES.
ADDITIONALLY, TWO AREAS OF CONCERN FOR HEAVY RAINFALL WILL DEVELOP
INTO THURSDAY EVENING. AN UPPER LEVEL SHORTWAVE PASSING OVER THE
CENTRAL PLAINS WILL HELP TO TRIGGER THUNDERSTORMS ALONG AND AHEAD
OF A LIFTING WARM FRONT, LIKELY ORGANIZING INTO A CONVECTIVE
SYSTEM BRINGING MORE WIDESPREAD HEAVY RAIN TOTALS. TO THE NORTH,
STRONG DYNAMIC FORCING AHEAD OF THE UPPER-LEVEL SYSTEM OVER THE
NORTHERN PLAINS IS ALSO EXPECTED TO LEAD TO MORE WIDESPREAD,
ORGANIZED STORM DEVELOPMENT. SLIGHT RISKS OF EXCESSIVE RAINFALL
COVER BOTH SCENARIOS, WITH WET ANTECEDENT CONDITIONS IN BOTH
LOCATIONS ALSO CONTRIBUTING TO THE RISK FOR SOME SCATTERED
INSTANCES OF FLASH FLOODING.
ELSEWHERE, A BROAD AREA OF SHOWERS AND THUNDERSTORMS WILL CONTINUE
EASTWARD AHEAD OF A COLD FRONT STRETCHING FROM NEW ENGLAND
SOUTHWESTWARD THROUGH THE MID-ATLANTIC, OHIO/TENNESSEE VALLEYS,
AND INTO THE LOWER MISSISSIPPI VALLEY AND EASTERN PORTIONS OF THE
SOUTHERN PLAINS WEDNESDAY. MODERATE TO LOCALLY HEAVY RAINFALL CAN
EXPECTED, WITH A FEW ISOLATED INSTANCES OF FLASH FLOODING
POSSIBLE. A FEW MORE POTENT AND WIDESPREAD STORMS OVER PORTIONS OF
THE MID-ATLANTIC/UPPER OHIO VALLEY AND THE OZARKS/LOWER
MISSISSIPPI VALLEY COULD BRING THE THREAT FOR SOME DAMAGING WINDS,
WITH SLIGHT RISKS OF SEVERE WEATHER COVERING BOTH LOCATIONS. THE
FRONT WILL CLEAR THE EAST COAST OVER NEW ENGLAND AND THE
MID-ATLANTIC THURSDAY WHILE PUSHING FURTHER INTO THE SOUTHEAST,
WITH STORM CHANCES MOVING INTO THE CAROLINAS SOUTHWESTWARD THROUGH
THE CENTRAL GULF COAST. ANOTHER DAY OF DIURNAL SEA BREEZE DRIVEN
STORMS IS FORECAST FOR FLORIDA WEDNESDAY BEFORE CONDITIONS BEGIN
TO DRY OUT ON THURSDAY.
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