717
FXUS02 KWBC 110703
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
303 AM EDT THU JUL 11 2024
VALID 12Z SUN JUL 14 2024 - 12Z THU JUL 18 2024
...ABOVE AVERAGE TEMPERATURES FORECAST FOR MUCH OF THE NATION NEXT
WEEK...
..OVERVIEW
PERSISTENT UPPER LEVEL RIDGING WILL BE IN PLACE NEXT WEEK ACROSS
THE INTERIOR WEST, SOUTHEAST, AND SOUTH-CENTRAL U.S. AND WILL
BRING ABOVE NORMAL TEMPERATURES TO MUCH OF THE NATION. THE RIDGE
WILL GRADUALLY WEAKEN THROUGH THE WEEK, AND TEMPERATURES SHOULD
BECOME LESS EXTREME. MEANWHILE, A SERIES OF POTENT UPPER LEVEL
SHORTWAVES WILL SWING ACROSS THE UPPER MIDWEST, GREAT LAKES, AND
NORTHEAST, AND A COUPLE OF FRONTAL BOUNDARIES WILL SINK SOUTH
ACROSS THE NORTH-CENTRAL U.S. AND THE NORTHEAST. PRECIPITATION
CHANCES WILL INCREASE ALONG THESE FRONTAL BOUNDARIES, AND DAILY
PRECIPITATION CHANCES WILL ALSO EXIST IN THE FOUR CORNERS REGION
AS MONSOONAL MOISTURE FOCUSES OVER THE AREA.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON THE OVERALL PATTERN,
WITH AN EXPECTED AMOUNT OF SPREAD/UNCERTAINTY IN THE DETAILS. THE
MOST IMPACTFUL UNCERTAINTY WILL LIKELY SURROUND THE TIMING OF
NORTHERN STREAM SHORTWAVES, WHICH WILL AFFECT THE TIMING AND
LOCATION OF FRONTS AND SENSIBLE WEATHER AT THE SURFACE. THESE
DIFFERENCES WILL BE RESOLVED WITH TIME.
GIVEN PRETTY GOOD OVERALL AGREEMENT, THE WPC FORECAST MODEL BLEND
WAS COMPRISED OF A GENERAL DETERMINISTIC BLEND OF THE
GFS/ECMWF/CMC/UKMET, WITH SLIGHTLY MORE WEIGHT PLACED ON THE
GFS/ECMWF, FOR THE FIRST HALF OF THE PERIOD. ENSEMBLE MEANS FROM
THE GEFS/ECENS WERE ADDED TO THE BLEND FOR THE SECOND HALF OF THE
PERIOD TO SMOOTH OUT SOME DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
MONSOONAL MOISTURE WILL FOCUS OVER PORTIONS OF THE FOUR CORNERS
REGION, WHICH WILL ALLOW FOR DAILY ROUNDS OF PRECIPITATION THAT
COULD RESULT IN FLASH FLOODING, ESPECIALLY NEAR STEEP TERRAIN AND
BURN SCARS. A MARGINAL RISK OF EXCESSIVE RAINFALL REMAINS IN PLACE
FOR MUCH OF THE REGION ON DAY 4 (SUNDAY), AND ANOTHER MARGINAL RISK
AREA WILL LIKELY BE ADDED FOR DAY 5 (MONDAY) FOR MUCH OF THE FOUR
CORNERS REGION AND PORTIONS OF THE SOUTHERN ROCKIES AS MOISTURE
PUSHES NORTH.
FLOODING MAY ALSO BE A CONCERN IN THE GREAT LAKES AND NORTHEAST
WHERE UPPER LEVEL SHORTWAVES AND SURFACE FRONTS WILL PROVIDE
SUPPORT FOR MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS. WITH
AMPLE MOISTURE AND INSTABILITY IN PLACE ACROSS THESE REGIONS,
LOCALLY HEAVY RAINFALL WILL BE POSSIBLE AND MAY LEAD TO ISOLATED
INSTANCES OF FLASH FLOODING. A MARGINAL RISK OF EXCESSIVE RAINFALL
REMAINS IN PLACE FOR MUCH OF THE GREAT LAKES REGION ON DAY 4
(SUNDAY), AND A MARGINAL RISK WILL LIKELY BE INTRODUCED FOR THE
EASTERN GREAT LAKES AND NORTHEAST ON DAY 5 (MONDAY), ESPECIALLY
GIVEN THE HEIGHTENED SENSITIVITY IN THE NORTHEAST FOLLOWING HEAVY
RAINS THIS WEEK.
ELSEWHERE, PRECIPITATION CHANCES WILL PROGRESS SOUTH ACROSS THE
REST OF THE CENTRAL AND EASTERN U.S. MID-NEXT WEEK AS A COLD FRONT
MOVES SOUTH, AND DAILY PRECIPITATION CHANCES WILL PERSIST IN
FLORIDA WITH SUMMERTIME CONVECTION. LOCALLY HEAVY RAIN WILL BE
POSSIBLE IN THESE AREAS WITH ANY HEAVIER THUNDERSTORM ACTIVITY. THE
WEST COAST AND MUCH OF THE PACIFIC NORTHWEST WILL REMAIN DRY
THROUGH NEXT WEEK.
MUCH OF THE NATION WILL EXPERIENCE ABOVE AVERAGE TEMPERATURES
NEXT WEEK, BECOMING DANGEROUSLY HOT IN SOME LOCATIONS.
TEMPERATURES IN THE 110S ARE LIKELY TO CONTINUE ACROSS THE DESERT
SOUTHWEST, AND HIGHS NEAR OR ABOVE 100 WILL BE COMMON IN THE
CENTRAL/SOUTHERN PLAINS. TEMPERATURES MAY BECOME LESS HOT MID/LATE
WEEK FOR THE NORTH-CENTRAL AND NORTHEASTERN U.S. IN THE WAKE OF
THE FRONTAL SYSTEMS, WITH HIGHS DROPPING FROM THE 80S/90S TO THE
70S/80S.
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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