797
FXUS02 KWBC 062000
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 PM EST TUE JAN 6 2026
VALID 12Z FRI JAN 09 2026 - 12Z TUE JAN 13 2026
...TENNESSEE VALLEY TO SOUTHERN APPALACHIANS HEAVY RAIN THREAT
FOCUS ON FRIDAY...
..OVERVIEW
DEEP UPPER TROUGHING DIGGING THROUGH THE WESTERN U.S./ROCKIES AND
THROUGH SOUTH-CENTRAL CANADA FRIDAY WILL GRADUALLY PROGRESS
EASTWARD AND PHASE OVER THE WEEKEND WITH DEEPENDED LOW FORMATION NEAR
A STORMY GREAT LAKES REGION. THIS WILL PROMOTE MODERATE TO HEAVY
PRECIPITATION CHANCES ALONG AND AHEAD OF THE ASSOCIATED FRONTAL
BOUNDARY ACROSS THE EASTERN THIRD OF THE COUNTRY. WINTRY
PRECIPITATION INCLUDING A SWATH OF HEAVY SNOW IS EXPECTED ON THE
WRAP-BACK SIDE OF THE SYSTEM/MAIN LOW INTO THE UPPER MIDWEST AND
GREAT LAKES WHERE ENHANCED LAKE EFFECT ACTIVITY WILL FLOURISH IN
THE COLD WAKE OF SYSTEM PASSAGE. AHEAD OF THIS FRONT, RECORD HIGH
PRE-FRONTAL TEMPERATURES ARE EXPECTED INTO FRIDAY/SATURDAY FOR
PORTIONS OF THE EAST-CENTRAL TO EASTERN STATES. ONCE THE FRONT
CLEARS THE EAST COAST THIS WEEKEND, MUCH OF THE COUNTRY WILL BE DRY
SUNDAY INTO EARLY NEXT WEEK UNDERNEATH SPRAWLING HIGH PRESSURE, BUT
EXPECT RENEWED RAINFALL TO THE PACIFIC NORTHWEST AND PERHAPS TEXAS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE SOLUTIONS ARE REASONABLY WELL CLUSTERED FOR FRIDAY/SATURDAY
DESPITE LOCAL WEATHER FOCUS VARIANCES SEEMINGLY BEST MITIGATED BY A
GFS/ECMWF/CANADIAN MODEL COMPOSITE IN AN ACTIVE PATTERN WITH
AVERAGE TO BETTER PREDICTABILITY. FAVOR A TRANSITION SUNDAY TO A
GEFS/ECMWF/CANADIAN ENSEMBLE MEAN BLEND THROUGH LONGER TIME FRAMES
AMID QUICKLY GROWING FORECAST SPREAD AND UNCERTAINTIES. RECENT
MODEL RUNS HAVE BEEN OFFERING WAY LESS THAN STELLAR CYCLE TO CYCLE
CONTINUITY WITH THE HANDLING AND PHASING OF MULTI-STREAM SYSTEM
ENERGIES DIGGING INTO THE WEST-CENTRAL TO EASTERN U.S. COMPARED TO
MORE CONSISTENT YET STILL UNCERTAIN ENSEMBLE MEAN GUIDANCE. LATEST
12 UTC MODEL GUIDANCE, ESPECIALLY THE ECMWF, CONTINUES TO SHOW
SIGNIFICANT TO WILD RUN-RUN CHANGES, NOW WITH A PROGRESSIVE TREND.
..WEATHER/HAZARDS HIGHLIGHTS
AMPLE GULF MOISTURE (WITH HIGHLY ANOMALOUS VALUES ABOVE THE 95TH
PERCENTILE) WILL STREAM AHEAD OF THE CENTRAL U.S. TROUGH TO PRODUCE
WIDESPREAD RAIN FROM THE GULF COAST TO THE OHIO VALLEY, MID-
ATLANTIC, AND NORTHEAST FRIDAY INTO SATURDAY. MODELS ARE SHOWING AN
INCREASING SIGNAL FOR HEAVY TO EXCESSIVE RAINFALL POTENTIAL,
PARTICULARLY FRIDAY ACROSS PORTIONS OF THE TENNESSEE VALLEY AND
INTO THE SOUTHERN APPALACHIANS. GIVEN THE ANOMALOUS MOISTURE AND
SOME INSTABILITY (ESPECIALLY SOUTH) WENT AHEAD WITH A SLIGHT RISK
UPGRADE FOR THE DAY 4/FRIDAY ERO PERIOD FROM NORTHEAST MISSISSIPPI
TO CENTRAL TENNESSEE WHERE MODEL 24-HOUR QPFS SHOW SUPPORT FOR 2-4+
INCHES OF RAIN AND SOME POTENTIAL FOR TRAINING ALONG THE INITIALLY
SLOW TO MOVE BOUNDARY. BY SATURDAY, THE PRECIPITATION MOVES INTO
THE EAST AND THE FRONTAL BOUNDARY SHOULD BE PROGRESSIVE ENOUGH BY
THAT TIME TO PRECLUDE A RISK AREA ON THE DAY 5 ERO AT THIS TIME.
PRECIPITATION SHOULD CLEAR THE COAST BY SUNDAY, WITH SOME POSSIBLE
SHOWERS LINGERING ACROSS FLORIDA.
ON THE COLD SIDE OF THIS SYSTEM, THERE IS THE POTENTIAL FOR
ACCUMULATING SNOW FROM THE CENTRAL PLAINS TO THE UPPER MIDWEST AND
NORTHERN GREAT LAKES FRIDAY INTO SATURDAY. THE SIGNAL IS GROWING FOR
A SWATH OF WRAP-BACK HEAVY SNOW AND BLOWING WINDS OVER THE UPPER
MIDWEST AND GREAT LAKES. LAKE EFFECT SNOWS WILL CONTINUE INTO
SUNDAY DOWNWIND OF FAVORABLE LOCATIONS. AFTER THIS THOUGH, MUCH OF
THE COUNTRY BY EARLY NEXT WEEK WILL BE DRY WITH THE EXCEPTION OF
WESTERN WASHINGTON IN FAVORABLE DEEP LAYERED SOUTHERLY FLOW NUDGING
INTO THE REGION AND POSSIBLY PARTS OF THE SOUTHERN PLAINS
CONTINGENT ON INDUCED RETURN FLOW BY SOUTHERN STREAM TROUGH ENERGY.
TEMPERATURES ARE LIKELY TO BE WELL ABOVE AVERAGE ACROSS THE
EASTERN THIRD OF THE COUNTRY FRIDAY INTO SATURDAY AHEAD OF THE BIG
TROUGH, WITH TEMPERATURE ANOMALIES OF 15 TO 25 DEGREES ABOVE
NORMAL. DAILY RECORDS FOR WARM LOWS AND HIGHS COULD BE SET ACROSS
THE SOUTHERN TIER AND INTO PARTS OF THE MID-ATLANTIC. TEMPERATURES
WILL RETURN TO NORMAL FROM WEST TO EAST FOLLOWING THE FRONTAL
PASSAGE. MEANWHILE THE WEST/SOUTHWEST MAY START BELOW NORMAL BUT
SHOULD TREND WARMER WITH TIME AS A RIDGE DEVELOPS OVER MUCH OF THE
REGION. THIS RIDGE WILL ALSO BUILD INTO THE NORTH-CENTRAL U.S. THIS
WEEKEND WITH THE RETURN OF ABOVE TO WELL ABOVE NORMAL TEMPERATURES.
SANTORELLI/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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