265
FXUS02 KWBC 111859
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 PM EDT WED JUN 11 2025
VALID 12Z SAT JUN 14 2025 - 12Z WED JUN 18 2025
...BROAD HEAVY RAIN/FLASH FLOOD THREAT FROM THE SOUTH-CENTRAL U.S.
TO THE TENNESSEE/OHIO VALLEYS AND MID-ATLANTIC INTO THE WEEKEND...
..GENERAL OVERVIEW
IT GENERALLY REMAINS THE CASE THAT A SLOW MOVING SHORTWAVE TROUGH
ALOFT MAY BE GRADUALLY LIFTING OUT OF THE SOUTH-CENTRAL U.S. THIS
WEEKEND AND THEN MAY ALSO PROVE SLOW TO MOVE OUT OF THE OHIO
VALLEY/MID-ATLANTIC REGION WITH PERIODIC RELOADING FROM IMPULSE
ENERGY DIGGING TO THE LEE OF AN AMPLIFIED UPSTREAM RIDGE. THIS WILL
KEEP THE WEATHER UNSETTLED THROUGH MUCH OF THE PERIOD WITH
WIDESPREAD SHOWERS AND THUNDERSTORMS TO INCLUDE HARD TO PINPOINT,
BUT VIABLE THREATS FOR HEAVY TO EXCESSIVE RAINFALL OVER A BROAD
AREA. SHORTWAVE ENERGY ORIGINATING FROM TROUGHING OVER THE WEST
COAST WILL MEANWHILE SLIDE OVER THE NORTHERN TIER STATES WITH
ACCOMPANYING SHOWERS AND STORMS. TROUGHING, IN SOME FORM, SHOULD
MAINTAIN ACROSS THE WESTERN U.S. INTO NEXT WEEK. UPPER RIDGING WILL
FOCUS HIGH HEAT OVER THE SOUTHWEST THIS WEEKEND INTO NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE REMAINS IN REASONABLY GOOD AGREEMENT WITH MOST OF THE
SYNOPTIC SCALE FEATURES AND OFFERS GOOD PATTERN PREDICTABILITY.
HOWEVER, GUIDANCE CONTINUES TO SUFFER FROM NUMEROUS SMALLER SCALE
SYSTEM AND CONVECTIVE FOCUS ACROSS THE BOARD. ACCORDINGLY, THE WPC
MEDIUM RANGE PRODUCT SUITE WAS MAINLY DERIVED FROM A BLEND OF
GFS/ECMWF/CMC/UKMET MODEL AND GEFS/ECMWF/CANADIAN ENSEMBLE MEAN
SOLUTIONS ALONG WITH THE NATIONAL BLEND OF MODELS AND WPC
CONTINUITY THROUGH MEDIUM RANGE TIME SCALES. THE BLENDING PROCESS
TENDS TO SMOOTH SYSTEM DETAIL CONSISTENT WITH FEATURE PROBABILITY.
APPLIED MANUAL ADJUSTMENTS TO ENSURE SUFFICIENT QPF AS WARRANTED
WITH AREAS OF ENHANCED MOISTURE/INSTABILITY AND SLOW TRANSLATION.
..WEATHER/HAZARDS HIGHLIGHTS
DAILY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE WIDESPREAD FROM
THE SOUTHERN PLAINS AND GULF COAST TO THE OHIO VALLEY/MID-ATLANTIC
AND INTO THE NORTHEAST ASSOCIATED WITH PERSISTENT AND PESKY UPPER
LEVEL IMPULSE/TROUGH ENERGIES IMPACTING THE BROAD REGION. THERE
REMAINS A LOT OF UNERTAINTY IN THE DETAILS, BUT THERE IS SOME
GENERAL AGREEMENT THAT HEAVIER RAINS MAY FOCUS ALONG/NEAR SLOW
MOVING AND WAVY DRAPING FRONTAL BOUNDARIES AND WITH LOCAL
BOUNDARIES WITH A MOIST AND UNSTABLE SURROUNDING ENVIRONMENT FROM
THE CENTRAL TO EASTERN U.S.. OPTED TO MAINTAIN VERY BROAD WPC
MARGINAL RISK AREAS ON BOTH THE DAYS 4 AND 5 EXCESSIVE RAINFALL
OUTLOOKS (EROS) FOR THIS WEEKEND STRETCHED FROM THE SOUTHERN
PLAINS AND GULF COAST NORTHEASTWARD THROUGH THE TENNESSEE/OHIO
VALLEYS TO THE MID-ATLANTIC. THESE AREAS CONTINUE TO BECOME
SLIGHTLY MORE DEFINED AS WE LEAD INTO THE EVENT. THIS IS A WET
PATTERN. IT IS HIGHLY LIKELY EMBEDDED SLIGHT RISKS AREAS WILL BE
NEEDED ONCE GUIDANCE SIGNALS BECOME MORE DEFINED CLOSER TO
OCCURANCE. FARTHER NORTH, SHORTWAVE ENERGY THROUGH THE NORTHERN
TIER WILL SUPPORT SHOWERS AND STORMS, WITH A MARGINAL RISK
HIGHLIGHTED ON THE DAY 5/SUNDAY ERO FOR CONVECTIVE COMPLEX
POTENTIAL OVER THE NORTHERN PLAINS. MODERATE TO HEAVIER RAIN MAY
TRY TO MATERIALIZE ACROSS PARTS OF THE NORTH- CENTRAL U.S. TO
MONNITOR NEXT WEEK AS A STRONGER SHORTWAVE MOVES INTO THE PLAINS.
TEMPERATURES SHOULD REMAIN SLIGHTLY ABOVE NORMAL FOR MUCH OF THE
INTERMOUNTAIN WEST THIS WEEKEND UNDER THE INFLUENCE OF AN UPPER
RIDGE. TEMPERATURES SHOULD BE CLOSER TO NORMAL ALONG THE COAST.
SHORTWAVE ENERGY MOVING INTO THE REGION NEXT WEEK SHOULD HELP
MODERATE TEMPERATURES ACROSS THE INTERIOR WEST SOMEWHAT. TO THE
SOUTH, HEAT WILL BUILD ACROSS THE DESERT SOUTHWEST WITH HIGHS
MAKING A RUN AT 110 DEGREES FOR THE LOWER ELEVATIONS OF SOUTHERN
ARIZONA AND SOUTHEAST CALIFORNIA, WITH HEAT RISK LIKELY REACHING
THE MAJOR CATEGORY BY SUNDAY AND MONDAY, WITH ADDITIONAL THREAT
EXTENDING WELL INTO NEXT WEEK. MEANWHILE, SLIGHTLY BELOW AVERAGE
TEMPERATURES ARE LIKELY FROM THE UPPER MIDWEST TO THE GREAT LAKES
AND NORTHERN NEW ENGLAND GOING INTO THE WEEKEND AS THIS REGION WILL
BE NORTH OF THE MAIN FRONTAL BOUNDARY.
SCHICHTEL/SANTORELLI
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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