679
FXUS02 KWBC 120707
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
307 AM EDT FRI JUL 12 2024
VALID 12Z MON JUL 15 2024 - 12Z FRI JUL 19 2024
...HAZARDOUS TO DANGEROUS HEAT FOR PARTS OF THE CENTRAL TO EASTERN
U.S. EARLY NEXT WEEK. HIGH HEAT BUILDS OVER THE WEST NEXT WEEK...
..OVERVIEW
UPPER LEVEL RIDGING WILL BE IN PLACE NEXT WEEK ACROSS THE INTERIOR
WEST, SOUTHEAST, AND SOUTH-CENTRAL U.S. TO BRING ABOVE NORMAL TO
HAZARDOUS TEMPERATURES TO MUCH OF THE NATION. UPPER TROUGH
DEVELOPMENT OFF THE WEST COAST NEXT WEEK MAY ACT TO BUILD UPPER
RIDGING OVER THE WEST. THIS WOULD ALLOW ENERGIES DIGGING TO THE
LEE TO INCREASINGLY WORK INTO DOWNSTREAM RIDGING OVER THE SOUTH.
MEANWHILE, A SERIES OF POTENT UPPER LEVEL SHORTWAVES WILL SWING
ACROSS THE UPPER MIDWEST, GREAT LAKES, AND NORTHEAST, AND A COUPLE
OF TEMPERATURE MODERATING FRONTAL BOUNDARIES WILL SINK SOUTH ACROSS
THE NORTH-CENTRAL U.S. AND THE NORTHEAST, WITH POTENTIAL TO SINK
DOWN INTO THE SOUTH/SOUTHEAST LATER PERIOD. 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
18 UTC GFS/GEFS AND 12 UTC ECMWF/UKMET/ECMWF ENSEMBLE MEAN
GUIDANCE SEEMS BEST CLUSTERED MONDAY INTO WEDNESDAY. PREFER A
COMPOSITE TO SMOOTH THE LEAST PREDICTABLE ROUGH EDGES. THIS SEEMS
GENERALLY IN STEP WITH THE 01 UTC NATIONAL BLEND OF MODELS (NBM)
AND WPC CONTINUITY IN A PATTERN WITH AT LEAST SLIGHTLY ABOVE NORMAL
PREDICTABILITY. FORECAST SPREAD OVERALL STAYS MANAGABLE INTO LATER
NEXT WEEK, BUT EMBEDDED SYSTEM TIMING DIFFERENCES DO STEADILY
GROW. LEANED WPC BLEND WEIGHTING FOR THIS PERIOD TOWARD THE
ECMWF/ECMWF ENSEMBLE MEAN THAT SHOW SOMEWHAT STRONGER BUILDING AND
MAINTAINANCE OF UPPER RIDGING OVER THE WEST. THIS SEEMS REASONABLE
GIVEN RELUCTANCE TO UNCHARACTERISTICALLY FAVOR WEAKENING GIVEN
TRENDS FOR FLOW AMPLIFICATION. NEWER 00 UTC CYCLE GUIDANCE REMAINS
OVERALL IN LINE AND TRENDS SLIGHTLY TOWARD THIS FORECAST PLAN.
..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 PLANNED
IS FOR DAY 4 (MONDAY) AND DAY 5 (TUESDAY) FOR MUCH OF THE FOUR
CORNERS REGION AND PORTIONS OF THE SOUTH-CENTRAL ROCKIES IN A
REGION WITH PROTRACTED FAVORABLE UPPER DIFFLUENCE, WITH SOME FOCUS
ALSO SPILLING INTO THE CENTRAL HIGH PLAINS AND SOUTHWEST TEXAS.
ACROSS THE GREAT LAKES AND NORTHEAST, UPPER LEVEL SHORTWAVES AND
WELL DEFINED AND WAVY 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 WPC MARGINAL RISK OF EXCESSIVE RAINFALL OUTLOOK
(ERO) REMAINS IN PLACE FOR THE GREAT LAKES AND NORTHEAST ON DAY 4
(MONDAY), ESPECIALLY GIVEN THE HEIGHTENED SENSITIVITY IN THE
NORTHEAST FOLLOWING HEAVY RAINS THIS WEEK. THE STORM PREDICTION
CENTER ALSO HIGHLIGHTS MIDWEST PARTS OF THIS REGION FOR SOME SEVERE
WEATHER. A DAY 5 (TUESDAY) MARGINAL RISK ERO HAS ALSO BEEN
INTRODUCED DOWN ACROSS THIS REGION AND INTO THE OHIO AND MID-
MISSISSIPPI VALLEYS AS THE MAIN FRONTAL ZONE SHIFTS SOUTHEASTWARD.
ELSEWHERE, PRECIPITATION CHANCES WILL PROGRESS FURTHER SOUTHWARD
ACROSS MUCH OF 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 MAINLY DRY THROUGH NEXT WEEK.
MUCH OF THE NATION WILL EXPERIENCE ABOVE AVERAGE TEMPERATURES
NEXT WEEK AND A THREAT A WIDESPREAD RECORD VALUES WHILE BECOMING
DANGEROUSLY HOT FOR MANY FROM ESPECIALLY THE CENTRAL TO EASTERN
U.S.. HAZARDOUS HEAT SHOULD SLOWLY SUPPRESS SOUTH AND EASTWARD WITH
TIME AS AMPLIFIED TROUGHING DIPS INTO THE GREAT LAKES AND
NORTHEAST/MID- ATLANTIC. 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 ACROSS
THE NORTHWEST MAY BE MARGINALLY ABOVE NORMAL THROUGH EARLY NEXT
WEEK, BUT AS UPPER RIDGING BUILDS BACK IN, ANOMALIES TICK UPWARD
AGAIN IN A PATTERN WITH INCREASING HOT CONDITIONS OVER THE WEST.
SCHICHTEL
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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