413
FXUS02 KWBC 060605
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
205 AM EDT TUE OCT 6 2026
VALID 12Z FRI OCT 09 2026 - 12Z TUE OCT 13 2026
...EXCESSIVE RAINFALL/FLASH FLOOD THREAT CONTINUES FOR PORTIONS OF
THE GULF COAST AND SOUTHEAST THROUGH THIS WEEKEND...
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE CONTINUES TO SHOW AGREEMENT WITH THE
MEAN TROUGH OVER EASTERN U.S. GRADUALLY PUSHING OFFSHORE, WHILE
THE WESTERN TROUGH MOVES INLAND. THE HIGHEST UNCERTAINTY REMAINS
WITH THE WESTERN TROUGH, ESPECIALLY WHEN THE SOLUTIONS DIVERGE
TOWARDS SUNDAY. DETERMINISTIC MODELS SHOW THAT DEPENDING ON THE
EVENTUAL POSITION AND STRENGTH OF THE CUTOFF LOW OVER THE
NORTHWEST, PERIODS OF RAIN AND MOUNTAIN SNOW CAN PERSIST INTO EARLY
NEXT WEEK ACROSS THE NORTHWEST AND NORTHERN ROCKIES. ENSEMBLE
MEANS SOLUTION TENDS TO AVOID EMPHASIZING A HIGHLY SPECIFIC
EVOLUTION AND SMOOTH SOME OF THE EXTREME PRECIPITATION AMOUNTS.
THEREFORE, CONTINUED USE OF THE ENSEMBLE MEANS AND MULTI- MODEL
BLEND IS FAVORED TO LIMIT SENSITIVITY TO INDIVIDUAL DETERMINISTIC
SOLUTIONS.
..PATTERN OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
THE BROAD TROUGHING ACROSS EASTERN U.S. WILL BEGIN TO PUSH OFFSHORE
THROUGH THE WEEKEND, WHILE A MORE COMPLEX SPLIT-FLOW REGIME
DEVELOPS OVER THE WEST. THE MOST SIGNIFICANT RAIN THREAT THROUGH
THE WEEKEND WILL BE ACROSS THE GULF COAST INTO THE SOUTHEAST AS A
SLOW-MOVING FRONTAL BOUNDARY REMAINS STRETCHED ACROSS THE
SOUTHEAST/GULF COAST. THE DISTURBANCE LIFTING NORTHEASTWARD FROM
THE GULF WILL ENCOUNTER ABUNDANT MOISTURE AND SUFFICIENT
INSTABILITY, LEADING TO ENHANCED RAINFALL RATES ALONG THE FRONTAL
BOUNDARY. LOCALLY FLASH FLOODING WILL BE POSSIBLE OVER AREAS THAT
WILL RECEIVE REPEATED CONVECTION. THIS IS HIGHLIGHTED WITH A
SLIGHT RISK IN THE WPC EXCESSIVE RAINFALL OUTLOOK DAY4/FRIDAY FOR
PORTIONS OF THE GULF COAST. THE FRONTAL BOUNDARY WILL CONTINUE TO
LIFT NORTHEAST THROUGH THE WEEKEND, SHIFTING THE AXIS OF HEAVIER
RAINFALL TOWARDS PORTIONS OF OHIO/TENNESSEE VALLEY AND MID-
ATLANTIC BY SATURDAY. THEREFORE, THE SLIGHT RISK EXPANDS FURTHER
NORTH INTO PORTIONS OF THE SOUTHEAST FOR DAY5/SATURDAY, WHILE A
MARGINAL COVERS PORTIONS OF THE TENNESSEE VALLEY. SHOWERS WILL
CONTINUE TO EXTEND FURTHER NORTH ACROSS PORTIONS OF THE NORTHEAST
BY SUNDAY.
ACROSS THE WEST, THE WEAKENING RIDGE AND DEVELOPING UPPER TROUGH
WILL BRING A SIGNIFICANT WEATHER PATTERN CHANGE. TEMPERATURES
ACROSS PACIFIC NORTHWEST INTO NORTHERN PLAINS WILL TRANSITION TO
BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
ADDITIONALLY, MOISTURE COMBINING FROM TROPICAL CYCLONE RACHEL AND
THE PACIFIC TROUGH WILL BRING AN INCREASE IN PRECIPITATION CHANCES
ACROSS MUCH OF WESTERN U.S. STARTING WITH THE NORTHWEST ON FRIDAY THEN
EVENTUALLY SPREAD ACROSS THE INTERMOUNTAIN WEST, ROCKIES, AND
SOUTHWEST THROUGH THE WEEKEND. AS THE UPPER LOW BECOMES MORE
ESTABLISHED, RAINFALL AMOUNT SHOULD INCREASE THROUGH THE WEEKEND.
FURTHERMORE, SNOW LEVELS WILL LOWER WITH THE ARRIVAL OF COLDER AIR,
WHICH MAY LEAD TO HEAVY TO MODERATE MOUNTAIN SNOW. BY LATE SUNDAY
INTO MONDAY, THE FRONTAL BOUNDARY WILL SUPPORT SHOWERS EXPANDING
ACROSS THE PLAINS INTO THE UPPER MIDWEST.
OUDIT
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, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES
ARE AT:
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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