213
FXUS02 KWBC 021941
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EST FRI JAN 2 2026
VALID 12Z MON JAN 05 2026 - 12Z FRI JAN 09 2026
...ANOTHER ROUND OF RAIN AND MOUNTAIN SNOW FOR CALIFORNIA ON MONDAY...
..OVERVIEW
WITH TROUGHS OFF BOTH COASTS, FLOW ACROSS THE CONUS ITSELF SHOULD
BE PRETTY ZONAL EARLY NEXT WEEK, AS A LOW AMPLITUDE RIDGE CAUSING
WARMER THAN AVERAGE TEMPERATURES ACROSS THE CENTRAL U.S. GETS
FLATTENED ON THE NORTHERN SIDE BY A COUPLE OF NORTH-CENTRAL TO
NORTHEASTERN U.S. CLIPPER SYSTEMS. TROUGHING OFF THE WEST COAST MAY
CLOSE OFF INTO AN UPPER LOW OFF CALIFORNIA AND BRING ONE MORE
ROUND OF POSSIBLE HEAVY RAIN AND MOUNTAIN SNOW FOR CALIFORNIA ON
MONDAY. THIS SHORTWAVE/LOW SHOULD SHIFT INLAND ACROSS THE SOUTHWEST
AND EVENTUALLY THE CENTRAL STATES AS ADDITIONAL ENERGY DIVES DOWN
THE WEST COAST LATE WEEK. THIS POTENT ENERGY WILL DEVELOP DEEPER
TROUGHING MOVING THROUGH THE WEST WHILE RIDGING STRENGTHENS IN THE
EAST, YIELDING A MORE AMPLIFIED PATTERN. THE PATTERN WILL ALLOW FOR
AN INCREASE IN PRECIPITATION COVERAGE ACROSS THE CENTRAL U.S. FOR
MID TO LATE WEEK, WHILE SHIFTING WELL ABOVE NORMAL TEMPERATURES
INTO THE EAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE STARTS THE MEDIUM RANGE PERIOD MONDAY IN GOOD
AGREEMENT ON THE LARGE SCALE PATTERN. SHORTWAVES IN THE NORTHERN
TIER SHOW SOME MINOR SPREAD, BUT THE MAIN OUTLIER SEEMED TO BE THE
00Z CMC THAT WAS STRONGER THAN CONSENSUS WITH A MIDWEST TUESDAY TO
NORTHEAST WEDNESDAY SHORTWAVE. A MULTI-MODEL BLEND FAVORING THE
ECMWF AND GFS SEEMED TO WORK WELL FOR THIS ASPECT OF THE FORECAST.
A PRIMARY MODEL DIAGNOSTICS CONCERN CONTINUES TO BE THE TROUGHING
OFF THE WEST COAST ON MONDAY THAT MAY CLOSE OFF A LOW (OR AT LEAST
SEPARATE INTO THE SOUTHERN STREAM) BY TUESDAY AS IT MOVES TOWARD
CALIFORNIA. THE 00/06Z MODEL GUIDANCE WAS REASONABLY AGREEABLE WITH
THE TIMING OF THIS FEATURE ON TUESDAY-WEDNESDAY, THOUGH
INTERESTINGLY THE 12Z MODELS HAVE DIVERGED A BIT COMPARED TO THE
PREVIOUS CYCLE. NAMELY, THE 12Z CMC HAS SPED UP WHILE THE 12Z GFS
SLOWED DOWN. THE GFS IS NOT TOO FAR OFF FROM THE AIGFS AND AIFS
THOUGH, SO SOMEWHERE BETWEEN THAT AND THE MIDDLE GROUND ECMWF SEEMS
TO BE A REASONABLE POSITION, WITH SLIGHTLY MORE CONFIDENCE THAT
THE CMC IS TOO FAST. THEN MODELS AGREE THAT ADDITIONAL STRONG
VORTICITY WILL DROP INTO THE NORTHWEST AND DEEPEN TROUGHING ACROSS
THE WESTERN AND CENTRAL U.S. BY LATER WEEK, BUT WITH PLENTY OF
UNCERTAINTY IN THE DETAILS LIKE SHORTWAVES WITHIN THE TROUGH THAT
WOULD HAVE IMPACTS ON SURFACE LOW/FRONTAL POSITIONS. OVERALL,
BLENDED THE ECMWF AND GFS WITH INCREASING PROPORTIONS OF THE GEFS
AND EC ENSEMBLE MEANS AS THE PERIOD PROGRESSED TO MINIMIZE
INDIVIDUAL MODEL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
ENERGY DROPPING SOUTH AND DEVELOPING AN EASTERN PACIFIC/CALIFORNIA
UPPER LOW MONDAY-TUESDAY WILL LEAD TO YET ANOTHER ROUND OF
PRECIPITATION FOR MUCH OF CALIFORNIA ON MONDAY, AFTER A WET SHORT
RANGE PERIOD. A SURFACE FRONTAL SYSTEM WILL LIKELY DIRECT MOISTURE
FROM SOUTHWEST TO NORTHEAST INTO MAINLY NORTHERN AND CENTRAL
CALIFORNIA, WITH MOST MODEL GUIDANCE BACKING OFF ON NOTABLE
RAINFALL FARTHER SOUTH INTO THE TRANSVERSE RANGES. A MARGINAL RISK
REMAINS IN PLACE IN THE DAY 4/MONDAY ERO FOR ISOLATED FLOODING
POTENTIAL. ADDITIONAL SNOW IS LIKELY FOR THE HIGHER TERRAIN OF THE
SIERRA, AND RAIN AND MOUNTAIN SNOW ARE LIKELY FOR THE INTERMOUNTAIN
WEST AS WELL. MODEST PRECIPITATION IS FORECAST TO CONTINUE INTO
TUESDAY AND WEDNESDAY ACROSS THE SOUTHWEST AS THE UPPER ENERGY
MOVES EAST. MEANWHILE, NORTHERN STREAM ENERGY DROPPING INTO THE
NORTHWEST BY TUESDAY WILL PROMOTE PRECIPITATION FOR THAT REGION.
THE PACIFIC NORTHWEST CAN EXPECT MODERATE TO LOCALLY HEAVY
PRECIPITATION TUESDAY, BUT WITH DRIER ANTECEDENT CONDITIONS AND
RAIN RATES STAYING LOW, ALONG WITH HIGHER ELEVATIONS SEEING SNOW,
THIS IS NOT EXPECTED TO CAUSE EXCESSIVE RAINFALL THREATS. MODEST
PRECIPITATION COULD OVERSPREAD MUCH OF THE WEST INTO WEDNESDAY.
ELSEWHERE ACROSS THE COUNTRY, A COUPLE OF CLIPPER SYSTEMS ARE
FORECAST TO TRACK FROM THE UPPER MIDWEST TO THE GREAT LAKES AND
THEN THE NORTHEAST DURING THE FIRST HALF OF NEXT WEEKEND. THESE
RELATIVELY WEAK SYSTEMS COULD PRODUCE A SWATH OF LIGHT TO MODERATE
SNOW AND PERHAPS SOME MIXED WINTRY PRECIPITATION ALONG THE SOUTHERN
PORTION OF THE TRACK. THEN BY MIDWEEK, PHASING TROUGHING TRACKING
INTO THE ROCKIES/HIGH PLAINS FROM THE WEST COULD TAP INTO GULF
MOISTURE AND LEAD TO INCREASING RAIN CHANCES (AND PERHAPS SOME
THUNDERSTORMS) ACROSS SOUTHERN/CENTRAL PARTS OF THE PLAINS AND
MISSISSIPPI VALLEY INTO THE MID-SOUTH, AND GENERALLY EXPECT RAIN TO
OVERSPREAD THE TENNESSEE/OHIO VALLEYS BY THURSDAY. WINTRY
PRECIPITATION IS POSSIBLE ON THE WESTERN AND NORTHERN SIDES OF THE
PRECIPITATION SHIELD, BUT THIS REMAINS HIGHLY UNCERTAIN.
TEMPERATURES ARE LIKELY TO BE MUCH WARMER THAN AVERAGE ACROSS A
WIDE EXPANSE OF THE COUNTRY INTO MUCH OF NEXT WEEK, ESPECIALLY
ACROSS THE PLAINS AND MISSISSIPPI VALLEY, WHERE TEMPERATURE
ANOMALIES OF 15 TO 30 DEGREES ABOVE AVERAGE WILL BE COMMON AND SOME
DAILY RECORDS FOR WARM LOWS AND HIGHS COULD BE SET. UNSEASONABLY
WARM TEMPERATURES WILL GRADUALLY EXPAND AND SPREAD EASTWARD THROUGH
THE WEEK, REACHING THE EAST WITH +10 TO +15 ANOMALIES AFTER A
COLDER THAN AVERAGE START TO THE WEEK ACROSS THE NORTHEAST. THE
WEST/SOUTHWEST SHOULD REMAIN NEAR OR BELOW NORMAL MUCH OF THE WEEK
AS THE PATTERN TURNS MORE AMPLIFIED AND TROUGHING DEVELOPS, WHICH
COULD EVENTUALLY COOL TEMPERATURES IN THE PLAINS CLOSER TO AVERAGE.
TATE/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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