016
FXUS01 KWBC 291957
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
356 PM EDT THU JUN 29 2023
VALID 00Z FRI JUN 30 2023 - 00Z SUN JUL 02 2023
...SLIGHT RISKS OF EXCESSIVE RAINFALL ARE IN EFFECT OVER THE
CENTRAL US ON THURSDAY AND SATURDAY...
...THERE IS AN MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE MIDDLE MISSISSIPPI AND OHIO VALLEYS ON THURSDAY, AND AN
ENHANCED RISK OF SEVERE WEATHER OVER THE CENTRAL HIGH PLAINS
THURSDAY EVENING...
...EXCESSIVE HEAT WARNINGS AND ADVISORIES OVER PARTS OF THE
CENTRAL/SOUTHERN PLAINS, MIDDLE/LOWER MISSISSIPPI VALLEY, AND
CENTRAL GULF COAST...
...AIR QUALITY ALERTS OVER PARTS OF THE UPPER/MIDDLE MISSISSIPPI
VALLEY, GREAT LAKES, WESTERN OHIO VALLEY, CENTRAL APPALACHIANS,
NORTHEAST, AND MID-ATLANTIC...
A FRONTAL SYSTEM DRAPED ACROSS THE CENTRAL PLAINS CONTINUES TO
RESULT IN AREAS OF HEAVY PRECIPITATION ACROSS CENTRAL US,
INCLUDING AREAS OF SEVERE WEATHER. A SLIGHT RISK OF EXCESSIVE
RAINFALL (LEVEL 2/4) AND A MODERATE RISK OF SEVERE WEATHER (LEVEL
4/5) ARE IN EFFECT ACROSS PORTIONS OF THE LOWER OHIO RIVER VALLEY
INTO PORTIONS OF TENNESSEE AS A COMPLEX PRODUCES HEAVY
PRECIPITATION, HAIL, AND DAMAGING WIND GUSTS. A WARM AND MOIST
AIRMASS TO THE SOUTH IS HELPING TO PROVIDE AMPLE MOISTURE FOR THE
CURRENT CONVECTIVE ACTIVITY ACROSS THE REGION. ON THURSDAY
EVENING, THE FOCUS FOR HEAVY PRECIPITATION WILL SHIFT TOWARD
PORTIONS OF THE NORTH-CENTRAL ROCKIES AND HIGH PLAINS AS ENERGY
ROUNDING THE CLOSED UPPER LOW OVER THE WEST WILL INTERACT WITH A
SURFACE BOUNDARY IN THE NORTHERN ROCKIES, WHICH IS FORECAST TO
PRODUCE HEAVY PRECIPITATION AND SEVERE WEATHER ACROSS THE REGION,
INCLUDING REGIONS ALREADY SATURATED WITH RECENT HEAVY RAINS. A
SLIGHT RISK OF EXCESSIVE RAINFALL AND AN ENHANCED RISK OF SEVERE
WEATHER (LEVEL 3/5) ARE IN EFFECT OVER THE CENTRAL HIGH PLAINS DUE
TO THE EXPECTED FORMATION OF CONVECTION OVERNIGHT. ON FRIDAY, THIS
ENERGY WILL PROGRESS EASTWARD INTO THE CENTRAL PLAINS AND MIDWEST.
GIVEN THE MOIST ENVIRONMENT IN PLACE, WIDESPREAD CONVECTION IS
LIKELY TO INITIATE ACROSS THE REGION. AS A RESULT, A MARGINAL RISK
OF EXCESSIVE RAINFALL IS IN EFFECT FOR MUCH OF CENTRAL PLAINS ON
FRIDAY. ON SATURDAY, THE THREAT FOR EXCESSIVE RAINFALL INCREASES
AS SOUTHWESTERLY FLOW AHEAD OF A SURFACE TROUGH WILL FORCE AMPLE
MOISTURE INTO A REGION OF LARGE-SCALE ASCENT OVER THE MIDWEST,
INCLUDING AREAS IMPACTED BY HEAVY PRECIPITATION ON THURSDAY AND
FRIDAY. AS A RESULT, A SLIGHT RISK OF EXCESSIVE RAINFALL IS IN
EFFECT ACROSS THE MIDWEST ON SATURDAY.
A DEEP UPPER-LEVEL TROUGH OVER PORTIONS OF NEW ENGLAND AND THE
EAST COAST IS FORECAST TO CONTINUE LIFTING NORTHEASTWARD IN THE
SHORT TERM, PROVIDING A BREAK FROM THE CONVECTIVE ACTIVITY THAT
HAS IMPACTED THE REGION RECENTLY. A SLOW-MOVING FRONTAL SYSTEM AT
THE SURFACE WILL CONTINUE TO PROGRESS THROUGH EASTERN NEW ENGLAND
WHILE SLOWLY WEAKENING. THE COMBINATION OF MODEST FORCING AND
TERRAIN-INDUCED LIFT RESULTED IN A MARGINAL RISK FOR EXCESSIVE
RAINFALL TO BE ISSUED IN PORTIONS OF NORTHWESTERN MAINE AND THE
WHITE MOUNTAINS OF NEW HAMPSHIRE. AS THE TROUGH CONTINUES TO LIFT
NORTHEASTWARD, THE THREAT FOR HEAVY RAINFALL SHIFTS TOWARD THE
NEXT SYSTEM APPROACHING FROM THE MIDWEST. THERE ARE MARGINAL RISKS
FOR EXCESSIVE RAINFALL ON FRIDAY AND SATURDAY ACROSS THE REGION AS
LOCALLY HEAVY RAINFALL AMOUNTS ARE POSSIBLE AHEAD OF A FRONTAL
SYSTEM APPROACHING FROM THE NORTHWEST. ON FRIDAY, PORTIONS OF THE
OHIO VALLEY AND SOUTH-CENTRAL APPALACHIANS MAY SEE LOCALLY HEAVY
RAINFALL AHEAD OF THIS SYSTEM. ON SATURDAY, THE THREAT FOR HEAVY
RAINFALL SHIFTS NORTHEASTWARD INTO THE NORTH-CENTRAL APPALACHIANS
AND NORTHERN NEW ENGLAND. THE RISK FOR FLASH FLOODING IS
HEIGHTENED IN AREAS THAT HAVE ALREADY SEEN LOCALIZED HEAVY
RAINFALL RECENTLY. TEMPERATURES ACROSS THE REGION WILL REMAIN
RELATIVELY SEASONAL THROUGH THE FORECAST PERIOD, WITH A MODEST
WARMING TREND EXPECTED HEADING INTO THE WEEKEND.
THE UPPER-LEVEL RIDGE CENTERED OVER THE MID-SOUTH IS EXPECTED TO
BEGIN MOVING EAST AND GRADUALLY WEAKEN THROUGH SATURDAY. FOR
PORTIONS OF NORTHERN AND INTERIOR TEXAS, THIS MEANS THAT
TEMPERATURES WILL BE RETURNING TO NEAR SEASONAL VALUES, THOUGH
STILL GENERALLY ABOVE AVERAGE. FOR THE MID-SOUTH AND GULF COAST,
HAZARDOUS HEAT IS EXPECTED THROUGH THE END OF THE WORK WEEK
UNDERNEATH THE UPPER-LEVEL RIDGE. TEMPERATURES WILL NEAR TRIPLE
DIGITS, WITH MAXIMUM HEAT INDICES LIKELY EXCEEDING 110F ACROSS
PORTIONS OF THE MID-SOUTH, LOW-MID MISSISSIPPI VALLEY, AND
PORTIONS OF THE GULF COAST THROUGH SATURDAY. NIGHTTIME LOWS ARE
EXPECTED TO BE EXTREMELY WARM, AND POTENTIALLY RECORD BREAKING,
PROVIDING LITTLE RELIEF FOR THE HEAT AT NIGHT.
IN ADDITION TO THE CURRENT WEATHER ACTIVITY, CANADIAN WILDFIRE
SMOKE IS EXPECTED TO CONTINUE IMPACTING PORTIONS OF THE EASTERN US
OVER THE NEXT FEW DAYS. HOWEVER, AIR QUALITY IS EXPECTED TO
IMPROVE IN THE SHORT TERM AS A COMBINATION OF THUNDERSTORM
ACTIVITY AND DISPERSION OF SMOKE WILL ULTIMATELY RESULT IN
IMPROVING AIR QUALITY CONDITIONS FOR MUCH OF THE COUNTRY HEADING
INTO THE WEEKEND.
GENZ
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