238
FXUS02 KWBC 251808
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
208 PM EDT TUE JUN 25 2024
VALID 12Z FRI JUN 28 2024 - 12Z TUE JUL 02 2024
...HAZARDOUS HEAT THREATS TO FOCUS ACROSS PARTS OF THE SOUTH NEXT
WEEKEND AND INTO EARLY NEXT WEEK...
..OVERVIEW
AN UPPER LEVEL LOW/TROUGH WILL TRAVERSE THE NORTHERN TIER OF THE
NATION AND PUSH A SURFACE FRONTAL SYSTEM ACROSS PARTS OF THE
CENTRAL AND EASTERN U.S. LATE THIS WEEK INTO THE WEEKEND. THIS
SYSTEM WILL BRING A THREAT OF HEAVY RAINFALL TO PORTIONS OF THE
MIDWEST ON FRIDAY AND NORTHEAST ON SATURDAY. MEANWHILE, AN UPPER
LEVEL RIDGE WILL BUILD OVER THE SOUTH AND SOUTHEAST THIS WEEKEND,
AND THERE WILL BE AN INCREASED THREAT FOR HAZARDOUS HEAT FOR THESE
AREAS UNDER THE RIDGE THROUGH MUCH OF THE MEDIUM RANGE PERIOD. A
SECOND UPPER LEVEL LOW/TROUGH WILL MOVE INTO THE NORTHWEST LATE
THIS WEEKEND AND PUSH TOWARDS THE UPPER MIDWEST EARLY NEXT WEEK.
THIS SYSTEM WILL LIKELY BRING ANOTHER ROUND OF HEAVY RAINFALL TO
PARTS OF THE MIDWEST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE OVERALL
PATTERN THROUGH THE MEDIUM RANGE PERIOD WITH SOME EXPECTED
DIFFERENCES IN DETAILS. SOME TIMING DIFFERENCES WITH THE SECOND
UPPER LOW/TROUGH EARLY NEXT WEEK MAY HAVE AN AFFECT ON THE IMPACTS
OF SENSIBLE WEATHER, BUT THESE DETAILS WILL LIKELY BE IRONED OUT
AS THIS EVENTS GETS CLOSER TO THE SHORT RANGE PERIOD. GIVEN THE
AGREEMENT, A GENERAL MODEL BLEND (WITH ENSEMBLE MEANS LATER IN THE
PERIOD) WILL SERVE AS A GOOD STARTING POINT FOR THE WPC FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
THE FRONTAL SYSTEM MOVING ACROSS THE NORTHERN TIER LATE THIS WEEK
INTO THE WEEKEND WILL FOCUS HEAVY RAINFALL POTENTIAL OVER THE
MIDWEST ON FRIDAY. THIS HIGHEST RISK FOR EXCESSIVE RAINFALL
POTENTIALLY LEADING TO FLASH FLOODING WILL BE FROM SOUTHEASTERN
IOWA/NORTHEASTERN MISSOURI THROUGH NORTHERN ILLINOIS INTO SOUTHERN
WISCONSIN. PARTS OF THIS AREA RECEIVED HEAVY RAINFALL RECENTLY AND
WILL BE PARTICULARLY SENSITIVE TO IMPACTS FROM ANY ADDITIONAL
HEAVY RAINFALL.
AS THE FRONTAL SYSTEM PROGRESSES, PRECIPITATION CHANCES WILL
SPREAD INTO THE EASTERN U.S. AND AND BACK INTO THE CENTRAL PLAINS
AND SOUTHERN ROCKIES OVER THE WEEKEND. LATEST MODEL GUIDANCE HAS
BEEN SHOWING THE HEAVIEST PRECIPITATION DEVELOPING OVER EASTERN
OHIO THROUGH PENNSYLVANIA AND INTO CENTRAL NEW YORK ON SATURDAY,
AND SCATTERED INSTANCES OF FLASH FLOODING MAY BE POSSIBLE.
ANOTHER ROUND OF HEAVY RAIN IS FORECAST TO IMPACT PARTS OF THE
NORTHERN PLAINS AND UPPER MIDWEST MONDAY INTO TUESDAY AS A SECOND
UPPER LEVEL LOW/TROUGH MOVES ACROSS THE NORTHERN TIER. THIS SYSTEM
WILL REQUIRE CLOSE MONITORING GIVEN RECENT AND FORECAST HEAVY RAIN,
WHICH COULD CAUSE NEW FLOODING ISSUES AND EXACERBATE ANY ONGOING
FLOODING.
COVERAGE OF STORMS ACROSS THE SOUTHWEST SHOULD DECREASE LATER THIS
WEEK, BUT A SURGE OF MOISTURE FROM THE SOUTH WILL LIKELY MAINTAIN
OR SLIGHTLY INCREASE PRECIPITATION CHANCES ACROSS PORTIONS OF NEW
MEXICO AND ARIZONA THROUGH THE MEDIUM RANGE PERIOD. THIS WILL
BRING A RENEWED THREAT FOR FLASH FLOODING, PARTICULARLY OVER BURN
SCARS AND SLOT CANYONS. DAILY PRECIPITATION CHANCES WILL ALSO
PERSIST IN THE SOUTHEAST/FLORIDA AS ABOVE NORMAL MOISTURE LINGERS
OVER THE REGION.
HAZARDOUS HEAT POTENTIAL WILL FOCUS ACROSS THE SOUTH AND SOUTHEAST
UNDERNEATH A PERSISTENT UPPER RIDGE THROUGH THE WEEKEND INTO EARLY
NEXT WEEK. SEVERAL DAYS OF ABOVE NORMAL TEMPERATURES (BOTH DAYTIME
HIGHS AND NIGHTTIME LOWS) ARE FORECAST FROM THE CENTRAL AND
SOUTHERN PLAINS EASTWARDS. ABOVE AVERAGE HEAT WILL ALSO SPREAD
INTO THE MIDWEST AND GREAT LAKES REGION EARLY NEXT WEEK AS A WARM
FRONT LIFTS ACROSS THESE REGIONS.
DOLAN
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC MEDIUM
RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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