060
FXUS02 KWBC 130758
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 AM EDT SAT SEP 13 2025
VALID 12Z TUE SEP 16 2025 - 12Z SAT SEP 20 2025
..OVERVIEW
THE MOST PROMINENT UPPER-AIR FEATURE NEXT WEEK IS TROUGHING OVER
THE NORTH-CENTRAL STATES THAT SHIFTS TO THE GREAT LAKES BY NEXT
WEEKEND. RIDGES AND ABOVE NORMAL TEMPERATURES ARE ON EITHER SIDE
OF THIS TROUGH WITH FURTHER TROUGHING OVER THE SOUTHEAST THAT
BRINGS RAIN CHANCES AS IT LIFTS OVER OR OFF THE MID- ATLANTIC
THROUGH MIDWEEK AND AN APPROACHING TROUGH OVER THE NORTHEAST
PACIFIC THAT LIKELY CLOSES INTO A LOW OVER WASHINGTON STATE IN THE
MID TO LATE WEEK TIMEFRAME. TROUGHING IN THE EAST WITH THE
POTENTIAL FOR A LINGERING CLOSED LOW WOULD BRING INCREASING RAIN
CHANCES ALONG AT LEAST COASTAL AREAS OF THE CAROLINAS/SOUTHERN MID-
ATLANTIC.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE IS INITIALLY WELL CLUSTERED WITH THE POSTIVELY-TILTED
UPPER TROUGH OVER THE NORTH-CENTRAL U.S. TUESDAY THAT DRIFTS EAST
TO THE GREAT LAKES BY THE WEEKEND AND A POTENT UPPER TROUGH FROM
THE NORTHEASTERN PACIFIC THAT REACHES THE PACIFIC NORTHWEST COAST
ON WEDNESDAY. DIFFERENCES ARE WITH THE PROGRESSION OF A LOW OVER
THE SOUTHEAST TRACKING UP OR OFF THE MID-ATLANTIC COAST THROUGH
MIDWEEK AND WHETHER THE NORTHWEST TROUGH REMAINS SOMEWHAT
PROGRESSIVE (GFS SOLUTION) OR CLOSES INTO A STALLED LOW (ECMWF).
PREFERENCE IN THE WPC FORECAST IS WITH THE 12Z ECMWF FOR THE
NORTHWEST TROUGH SHIFTING INTO A LOW WHICH IS FURTHER SUPPORTED BY
THE 00Z ECMWF AS WELL AS THE 00Z CMC. OTHERWISE A GENERAL MODEL
BLEND SUFFICES THROUGH DAY 5 WITH A HEAVY RELIANCE ON ENSEMBLE
MEANS FOR DAYS 6/7. IT IS WORTH NOTING THAT THE EC AIFS IS IN THE
CAMP FOR A MORE SIGNIFICANT LOW OVER THE MID-ATLANTIC (MORE LIKE
THE 00Z GFS AND CMC) WHILE NOT IN FAVOR OF A CLOSED/STALLED LOW
OVER THE NORTHWEST.
..WEATHER/HAZARDS HIGHLIGHTS
UPPER TROUGHING OVER THE NORTHERN PLAINS TUESDAY AND WEDNESDAY WILL
ENCOURAGE ENHANCED GULF MOISTURE TRANSPORT UP THE PLAINS WITH
CONVERGENCE AHEAD OF A SLOW MOVING FRONTAL SYSTEM. HEAVY RAIN IS
LIKELY OVER THE CENTRAL PLAINS BOTH DAYS. THE DAY 4 MARGINAL RISK
ERO IS EXPANDED SOUTH INTO NORTHWEST KANSAS WHILE A NEW DAY 5
MARGINAL RISK ERO IS DRAWN JUST EAST OF THERE FROM EASTERN NEBRASKA
THROUGH SOUTHWEST MINNESOTA.
MONSOONAL MOISTURE GETS INTO SOUTHWEST NEW MEXICO ON TUESDAY WHICH
WARRANTS INCLUSION OF A SMALL DAY 4 MARGINAL RISK ERO FROM THE
WHITE MTNS OF AZ THROUGH THE MOGOLLON MTNS OF NM.
OTHERWISE, THE LOW MOVING UP THE CAROLINA AND MID-ATLANTIC COAST
SHOULD BRING SOME ONSHORE FLOW AND RAIN. THE WETTEST GUIDANCE IS
THE ECAIFS WHICH HAS A COAST HUGGING LOW TRACK WHILE CONVENTIONAL
GUIDANCE IS GENERALLY MORE OFFSHORE WITH THE TRACK. MEANWHILE, THE
TRAILING PORTION OF THE STATIONARY FRONT WILL LINGER OVER OR NEAR
SOUTH FLORIDA TUESDAY THROUGH THE REST OF THE WEEK WHICH MAY
EVENTUALLY REACH EXCESSIVE LEVELS WITH THE PROLONGED NATURE OF THE
HEAVY RAIN.
ELSEWHERE THE RIDGE AXIS OVER THE SOUTHWEST SHIFTS EAST STARTING
WEDNESDAY WHICH WILL SEND ANOMALOUS MOISTURE NORTH OVER SOUTHERN CA
LATER IN THE WEEK AND POTENTIALLY EXCESSIVE RAINFALL.
AN UPPER-RIDGE WILL PROMOTE HOT TEMPERATURES CENTERED ON THE
MIDWEST/MISSISSIPPI VALLEY THROUGH AT LEAST MID-NEXT WEEK, WITH
ANOMALIES OF 10-20 DEGREES ABOVE AVERAGE. TEMPERATURES WELL IN THE
90S WILL BE COMMON, AND A HANDFUL OF RECORD HIGHS ARE POSSIBLE BUT
CURRENTLY DO NOT LOOK TO BE WIDESPREAD. RECENT MODEL TRENDS
CONTINUE TO FAVOR SOME WARMER THAN AVERAGE TEMPERATURES TO MOVE
INTO THE NORTHEAST AS THE WEEK PROGRESSES. INITIALLY COOLER THAN
AVERAGE TEMPERATURES IN THE NORTHWEST LOOK TO MODERATE AS THE WEEK
PROGRESSES.
JACKSON
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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