718
FXUS01 KWBC 282001
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EDT FRI JUL 28 2023
VALID 00Z SAT JUL 29 2023 - 00Z MON JUL 31 2023
...EXCESSIVE HEAT ADVISORIES AND WARNINGS ARE IN EFFECT FOR
PORTIONS OF THE EAST COAST, CENTRAL/SOUTHERN PLAINS, AND OVER THE
SOUTHWEST...
...TEMPERATURE RELIEF EXPECTED FOR THE NORTHEAST AND MID-ATLANTIC
AS A COLD FRONT DESCENDS INTO THE NORTHERN TIER...
...AN ENHANCED RISK OF SEVERE THUNDERSTORMS IS IN EFFECT FOR
PORTIONS OF THE LOWER GREAT LAKES ON FRIDAY EVENING...
WIDESPREAD NEAR-RECORD HEAT CONTINUES TO IMPACT A LARGE PORTION OF
THE U.S. TODAY AS A LARGE UPPER-LEVEL RIDGE SITS OVER MUCH OF THE
CENTRAL AND EASTERN U.S. HEAT ADVISORIES AND WARNINGS ARE IN
EFFECT FOR THE MID-ATLANTIC, NORTHEAST, AND PORTIONS OF THE
CENTRAL PLAINS/MIDWEST. SOME CITIES CURRENTLY UNDER EXCESSIVE HEAT
WARNINGS INCLUDE VIRGINIA BEACH, WASHINGTON D.C., PHILADELPHIA,
ST. LOUIS, AND KANSAS CITY. THESE AREAS MAY SEE HIGH TEMPERATURES
CLIMB WELL NORTH OF 90F, EVEN 100F IN SOME AREAS. IN ADDITION,
OPPRESSIVE HUMIDITY CURRENTLY AFFECTING MUCH OF THE COUNTRY WILL
CONTRIBUTE TO WIDESPREAD HEAT INDICES OF 100-110+ OVER THESE
AREAS. NIGHTTIME TEMPERATURES MAY ONLY FALL INTO THE UPPER 70S AND
LOW 80S, WHICH WILL REDUCE OVERNIGHT RELIEF FROM THE DAYTIME HEAT.
MANY PLACES ARE SET TO BREAK THEIR TEMPERATURE RECORDS FOR DAYTIME
HIGHS AS WELL AS WARM NIGHTTIME LOWS THROUGH SATURDAY MORNING. IF
YOU ARE AFFECTED BY THIS HEAT WAVE, IT IS IMPERATIVE TO PRACTICE
HEAT SAFETY, ESPECIALLY IF SPENDING EXTENDED PERIODS OF TIME
OUTDOORS.
FOR THOSE ON THE EAST COAST, TEMPERATURE RELIEF ARRIVES SOONER
THAN LATER. AREAS OF SCATTERED THUNDERSTORMS ALONG AND PRECEDING A
COLD FRONT APPROACHING FROM CANADA MAY HELP TO LIMIT THE HEAT ON
SATURDAY FOR THOSE IN THE NORTHEAST. ON SUNDAY, THIS COLD FRONT
WILL PROGRESS THROUGH MID-ATLANTIC, ULTIMATELY ENDING THE HEAT
WAVE FOR MUCH OF THE EAST COAST. HOWEVER, OVER THE CENTRAL PLAINS
AND SOUTHERN TIER, A MORE GRADUAL RELIEF FROM THE HEAT IS
EXPECTED. A SURFACE COLD FRONT WILL SLOWLY DESCEND OVER THE
NORTHERN TIER OF THE COUNTRY AS THE UPPER-LEVEL RIDGE RESPONSIBLE
FOR THE HOT CONDITIONS FOCUSES OVER THE CENTRAL U.S. HIGH
TEMPERATURES OVER THE WEEKEND ARE SET TO BE IN THE MID TO UPPER
90S OVER MUCH OF THE CENTRAL AND SOUTHERN U.S., WITH HEAT INDEX
VALUES OF 100-105F. BY SUNDAY, TEMPERATURES OVER THE CENTRAL
PLAINS WILL TREND CLOSER TO AVERAGE FOR THIS TIME OF YEAR, AND THE
HEAT WAVE WILL FOCUS OVER THE SOUTHERN PLAINS AND GULF COAST.
A FEW AREAS OF SEVERE WEATHER AND HEAVY RAIN ARE EXPECTED TO FORM
DURING THE SHORT-TERM FORECAST PERIOD. THE STORM PREDICTION CENTER
HAS ISSUED AN ENHANCED RISK OF SEVERE THUNDERSTORMS (LEVEL 3/5)
OVER THE LOWER GREAT LAKES REGION, EFFECTIVE THROUGH SATURDAY
MORNING. UPPER-LEVEL ENERGY OVER THE NORTHERN PLAINS IS EXPECTED
TO INTERACT WITH AN EXTREMELY UNSTABLE AIR MASS CENTERED OVER
IOWA, WHICH WILL HELP TO CREATE AN AREA OF STRONG THUNDERSTORMS ON
FRIDAY EVENING. THE MAIN THREATS EXPECTED FROM THIS AREA OF
THUNDERSTORMS ARE DAMAGING WIND GUSTS AND LARGE HAIL.
ADDITIONALLY, WPC HAS ISSUED A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2/4) FOR THIS SYSTEM, NOTING THE POTENTIAL FOR REPEATED
ROUNDS OF THUNDERSTORMS WITH INTENSE RAINFALL RATES, CREATING
LOCALIZED FLASH FLOODING CONCERNS. ON SATURDAY, THIS AREA OF
THUNDERSTORMS IS EXPECTED TO CONTINUE INTO THE MID-ATLANTIC.
WIDELY-SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE
MID-ATLANTIC INTO SOUTHERN NEW ENGLAND AHEAD OF THE COLD FRONT.
THE STORM PREDICTION CENTER HAS ISSUED A SLIGHT RISK FOR SEVERE
THUNDERSTORMS (LEVEL 2/5) OVER THIS AREA, WITH DAMAGING WINDS
BEING THE PRIMARY SEVERE THREAT.
OVER THE SOUTHEAST, A TROPICAL UPPER-LOW AND ASSOCIATED SURFACE
SYSTEM CONTINUES TO FORCE A WIDE REGION OF SCATTERED THUNDERSTORMS
OVER THE REGION. THE SURFACE LOW IS EXPECTED TO PROGRESS NORTHWARD
THROUGH SOUTHEASTERN GEORGIA BEFORE EVENTUALLY WEAKENING OVER THE
WEEKEND. PERSISTENT ONSHORE FLOW MAY RESULT IN LOCALLY HEAVY
RAINFALL AMOUNTS ALONG THE SOUTHEAST COASTS OF GEORGIA AND SOUTH
CAROLINA ON FRIDAY EVENING. OVER THE SOUTHWEST, SUMMER HEAT WILL
CONTINUE, WITH PORTIONS OF THE SOUTHWEST AND SOUTHERN CALIFORNIA
SET TO EXPERIENCE NEAR RECORD HIGHS AND WARM NIGHTTIME LOWS. AN
GRADUAL INFLUX OF UPPER-LEVEL MOISTURE WILL BEGIN TO IMPACT THE
REGION, WHICH MAY RESULT IN AN INCREASE IN THUNDERSTORM COVERAGE
OVER THE COURSE OF THE WEEKEND.
GENZ
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