164
FXUS01 KWBC 160852
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
451 AM EDT SUN JUL 16 2023
VALID 12Z SUN JUL 16 2023 - 12Z TUE JUL 18 2023
...OVER 40 MILLION PEOPLE ARE UNDER A MODERATE RISK OF EXCESSIVE
RAINFALL FOR PARTS OF THE NORTHEAST TODAY WITH THE POTENTIAL FOR
SIGNIFICANT FLASH FLOODING, SLIGHT RISK OF SEVERE STORMS IN
SOUTHERN NEW ENGLAND...
...VARIOUS AREAS OF HEAVY SHOWERS AND THUNDERSTORMS THROUGHOUT THE
EAST & SOUTH, INCLUDING PARTS OF SOUTHERN ARIZONA...
...EXCESSIVE HEAT WARNINGS AND HEAT ADVISORIES PERSIST FROM THE
PACIFIC NORTHWEST, CALIFORNIA, AND THE GREAT BASIN TO PARTS OF THE
SOUTHERN PLAINS, CENTRAL GULF COAST, AND SOUTH FLORIDA...
...AIR QUALITY ALERTS OVER PARTS OF THE NORTHERN HIGH PLAINS,
MIDWEST, AND GREAT LAKES...
AS DAY BREAKS ON THIS SUNDAY, JULY 16, COPIOUS AMOUNTS OF MOISTURE
STREAMING AHEAD OF A COLD FRONT SLOWLY APPROACHING FROM THE WEST
WILL IGNITE NUMEROUS HEAVY SHOWERS AND STORMS FROM THE
MID-ATLANTIC TO THE NORTHEAST. THESE STORMS WILL BE CAPABLE OF
PRODUCING TORRENTIAL RAINFALL RATES AND MAY ALSO COINCIDE WITHIN
TRAINING AREAS OF THUNDERSTORMS. GIVEN SOME PARTS OF THE NORTHEAST
CONTAIN SATURATED AND SENSITIVE SOILS FROM RECENT HEAVY RAINFALL
OVER THE PAST 10 DAYS, THIS IS A SETUP PRIMED TO PRODUCE FLASH
FLOODING THAT COULD BE SIGNIFICANT IN AFFECTED AREAS. THE WEATHER
PREDICTION CENTER (WPC) HAS ISSUED A MODERATE RISK FROM THE
DELAWARE VALLEY ON NORTH AND EAST INTO CENTRAL NEW ENGLAND. THE
MODERATE RISK DOES INCLUDE THE NYC, PHILADELPHIA, HARTFORD, AND
BOSTON METRO AREAS. POTENTIAL IMPACTS AS A RESULT OF FLOODING
INCLUDE IMPASSABLE ROADWAYS, SWIFTLY FLOWING CREEKS AND STREAMS,
AND IN HIGHER TERRAIN LOCATIONS, POSSIBLE MUDSLIDES. THE SLIGHT
RISK AREA EXTENDS FROM THE VIRGINIA TIDEWATER ON NORTH TO NORTHERN
MAINE. THE STORM PREDICTION CENTER (SPC) ALSO ISSUED A SLIGHT RISK
FOR SEVERE WEATHER FROM THE NYC METRO AREA ON EAST TO INCLUDE ALL
OF SOUTHERN NEW ENGLAND. SEVERE STORMS WITHIN THE SLIGHT RISK AREA
HAVE THE MAY PRODUCE DAMAGING WIND GUSTS AND TORNADOES.
WHILE THE NORTHEAST FACES THE MORE SIGNIFICANT THREAT FOR FLASH
FLOODING TODAY, THERE ARE NO SHORTAGE OF OTHER AREAS THAT ARE ALSO
AT-RISK FOR BOTH EXCESSIVE RAINFALL AND SEVERE WEATHER. TODAY, SPC
HAS A SLIGHT RISK OF SEVERE STORMS IN THE CENTRAL PLAINS. BOTH WPC
AND SPC HAVE MARGINAL RISKS FOR EXCESSIVE RAINFALL AND SEVERE
STORMS THAT STRETCH FROM THE CENTRAL PLAINS TO THE MIDDLE
MISSISSIPPI VALLEY. BOTH NATIONAL CENTERS ALSO FEATURE MARGINAL
RISK AREAS FOR THE ARKLATEX AND ALONG PORTIONS OF THE GULF COAST.
BY MONDAY, THE THREAT FOR SEVERE STORMS AND EXCESSIVE RAINFALL
BECOMES MORE SCATTERED ACROSS THE COUNTRY. SPC POSTED A SLIGHT
RISK FOR SEVERE WEATHER IN SOUTHERN SOUTH DAKOTA AND NORTHERN
NEBRASKA WITH A FEW MARGINAL RISKS AREAS; ONE IN THE NORTH-CENTRAL
PLAINS, ONE IN CENTRAL MONTANA, AND THE OTHER IN THE OHIO VALLEY.
WHEN IT COMES TO EXCESSIVE RAINFALL, AREAS FROM THE EASTERN GREAT
LAKES ON SOUTH TO THE TENNESSEE VALLEY COULD WITNESS STORMS
POSSIBLY CAUSE AREAS OF FLASH FLOODING. THERE ARE ALSO MARGINAL
RISKS IN FLORIDA, THE CENTRAL GULF COAST, AND EVEN SOUTHERN
ARIZONA.
SPEAKING OF ARIZONA, "THE GRAND CANYON STATE" AND MANY OF ITS
NEIGHBORING STATES IN THE WEST WILL CONTINUE TO CONTEND WITH AN
ONGOING DANGEROUS HEAT WAVE. IN TOTAL, FROM SOUTH FLORIDA AND THE
GULF COAST TO THE SOUTHWEST, OVER 80 MILLION PEOPLE REMAIN UNDER
EITHER AN EXCESSIVE HEAT WARNING OR HEAT ADVISORY AS OF EARLY THIS
MORNING. IN THE SOUTHWEST TODAY, DAYTIME HIGHS WILL APPROACH THE
CENTURY MARK IN THE INTERIOR NORTHWEST, RANGE BETWEEN 100-110F
THROUGHOUT INTERIOR CALIFORNIA AND THE GREAT BASIN, AND EVEN TOP
115F IN PARTS OF THE HIGH DESERT OF SOUTHERN CALIFORNIA, SOUTHERN
NEVADA, AND SOUTHERN ARIZONA. WIDESPREAD RECORD BREAKING HIGH
TEMPERATURES, AS WELL AS RECORD BREAKING WARM DAILY MINIMUMS ARE
EXPECTED IN PARTS OF THE SOUTHWEST, ALONG THE WESTERN GULF COAST,
AND IN SOUTH FLORIDA. BY MONDAY, THE CORE OF RECORD BREAKING HEAT
SHIFTS MORE INTO THE FOUR CORNERS STATES WITH PARTS OF SOUTH TEXAS
AND SOUTH FLORIDA STILL SEEING POSSIBLE RECORD HEAT. THE
COMBINATION OF SIZZLING TEMPERATURES AND OPPRESSIVELY HIGH DEW
POINTS WILL RESULT IN SULTRY HEAT THROUGHOUT THE SOUTH INTO THE
UPCOMING WEEK. FOR MORE INFORMATION REGARDING BOTH ONGOING AND
POTENTIAL IMPACTS FROM THIS HEAT WAVE, PLEASE VISIT HEAT.GOV.
IN ADDITION TO THE FLOODING/SEVERE THREATS AND STIFLING HEAT, AIR
QUALITY ALERTS ARE IN PLACE FOR MUCH OF THE GREAT LAKES, MIDWEST,
AND NORTHERN HIGH PLAINS. THIS IS DUE TO THE LINGERING THICK
CONCENTRATION OF CANADIAN WILDFIRE SMOKE OVER THESE REGIONS. WHILE
THE CONCENTRATION OF SMOKE IN THE ATMOSPHERE SHOULD BEGIN TO WAIN
BY MONDAY, THERE IS STILL ENOUGH SMOKE TO SUPPORT UNHEALTHY AIR
QUALITY THAT IS UNHEALTHY FOR SENSITIVE GROUPS IN PARTS OF THESE
REGIONS INTO THE START OF THE UPCOMING WEEK.
MULLINAX
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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