281
FXUS01 KWBC 270707
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
306 AM EDT THU JUL 27 2023
VALID 12Z THU JUL 27 2023 - 12Z SAT JUL 29 2023
...DANGEROUS HEAT WAVE TO BEGIN IN NORTHEAST & MID-ATLANTIC ON
THURSDAY AND CONTINUE THROUGH WEEKEND...
...SEVERE THUNDERSTORMS AND FLASH FLOODING POSSIBLE THROUGHOUT
PORTIONS OF NORTHEAST ON THURSDAY...
...RECORD-BREAKING HEAT TO CONTINUE ACROSS SOUTHWEST AND CENTRAL
U.S. THROUGH END OF WEEK...
A DANGEROUS HEAT WAVE WILL BEGIN THURSDAY FOR MUCH OF THE I-95
CORRIDOR AS DAYTIME HIGH TEMPERATURES APPROACHING 100 F COMBINED
WITH OPPRESSIVE HUMIDITY WILL PRODUCE HEAT INDEX VALUES OF 105+ F
THROUGH SATURDAY. MAJOR METROPOLITAN AREAS SUCH AS WASHINGTON
D.C., PHILADELPHIA, AND BOSTON ARE UNDER A HEAT ADVISORY, WHILE AN
EXCESSIVE HEAT WARNING IS IN EFFECT FOR THE NEW YORK CITY METRO
AREA. NUMEROUS HIGH MAXIMUM AND HIGH MINIMUM TEMPERATURE RECORDS
ARE FORECAST TO BE BROKEN THROUGH SATURDAY, AS NIGHTTIME LOWS WILL
BE AS MUCH AS 10-15 DEGREES ABOVE AVERAGE FOR THE REGION,
EXACERBATING THE POTENTIAL HEAT-RELATED HEALTH IMPACTS. IT IS
IMPERATIVE THAT RESIDENTS IN THE NORTHEAST AND MID-ATLANTIC
PRACTICE HEAT SAFETY THIS WEEK AS THE HOTTEST STRETCH OF THE
SUMMER BEGINS ON THURSDAY AND CONTINUES THROUGH SATURDAY.
IN ADDITION TO THE HOT WEATHER, AN UPPER-LEVEL SHORTWAVE WILL HELP
DRIVE THE RISK FOR SEVERE WEATHER THROUGHOUT THE MID-ATLANTIC AND
NORTHEAST ON THURSDAY, RESULTING IN THE STORM PREDICTION CENTER
(SPC) HIGHLIGHTING AN AREA WITH A SLIGHT RISK OF SEVERE
THUNDERSTORMS FROM WASHINGTON D.C. NORTHWARD THROUGH PORTLAND, ME.
FURTHERMORE, ANOMALOUSLY MOIST AIR ADVECTING NORTHWARD AHEAD OF
THE SHORTWAVE WILL SET THE STAGE FOR POSSIBLE FLASH FLOODING
ACROSS NEW ENGLAND AS A CONVECTIVE COMPLEX PUSHES THROUGH THE
REGION PRODUCING HEAVY RAINFALL RATES ON TOP OF ALREADY WET SOILS.
AS A RESULT, A SLIGHT RISK OF EXCESSIVE RAINFALL HAS BEEN HOISTED
FOR THE REGION ON THURSDAY.
FURTHER WEST, HEAT WILL ALSO BE OF CONCERN THROUGHOUT THE CENTRAL
PLAINS, UPPER MISSISSIPPI VALLEY, OHIO VALLEY, AND MIDWEST AS
DAYTIME HIGH TEMPERATURES APPROACH AND EXCEED 100 F THROUGH THE
END OF THE WEEK. WIDESPREAD HEAT ADVISORIES ARE IN EFFECT THROUGH
FRIDAY EVENING AS DANGEROUS HEAT INDICES OF 105 F TO 110+ F ARE
EXPECTED. SOME RELIEF IS IN SIGHT FOR PORTIONS OF THE MIDWEST AS
ANOTHER FRONTAL SYSTEM IS FORECAST TO PUSH SOUTH FROM CANADA,
TRIGGERING SHOWERS AND THUNDERSTORMS IN THE UPPER MIDWEST AND
GREAT LAKES THURSDAY AFTERNOON INTO FRIDAY. SHOWERS AND
THUNDERSTORMS WILL THEN EXPAND INTO THE NORTHEAST AND MID-ATLANTIC
LATE FRIDAY INTO SATURDAY.
ELSEWHERE, DAILY DIURNAL SHOWERS AND THUNDERSTORMS ARE FORECAST TO
PERSIST ACROSS THE FOUR CORNERS REGION AND ALONG THE SEA BREEZE IN
THE SOUTH AND SOUTHEAST, AS THE RECORD-SETTING HEAT WAVE WILL
CONTINUE IN THE SOUTHWEST THROUGH THE END OF THIS WEEK.
RUSSELL
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