557
FXUS02 KWBC 060700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST THU FEB 6 2025
VALID 12Z SUN FEB 09 2025 - 12Z THU FEB 13 2025
...HEAVY RAIN DEVELOPING IN THE SOUTHEASTERN QUADRANT OF THE LOWER
48 MONDAY-WEDNESDAY...
...ROUNDS OF SNOW AND ICE ARE POSSIBLE STRETCHING FROM THE
CENTRAL PLAINS TO MID-ATLANTIC/NORTHEAST NEXT WEEK...
..OVERVIEW
THE SYNOPTIC PATTERN SETTING UP NEXT WEEK WILL CONSIST OF A
DEVELOPING POSITIVELY TILTED TROUGH AXIS IN THE INTERIOR WEST
TOWARD HUDSON BAY, WITH GENERAL SOUTHWESTERLY UPPER FLOW OVER THE
EAST THAT ALLOWS FOR SHORTWAVES MOVING THROUGH. ONE SHORTWAVE AND
SURFACE LOW WILL PULL AWAY FROM THE NORTHEAST SUNDAY AFTER
SPREADING SOME HEAVY SNOW TO THE REGION. RAIN CHANCES WILL INCREASE
FROM THE ARK-LA-TEX INTO THE SOUTHEAST MONDAY AND BEYOND, WITH
HEAVY RAIN AND FLOODING POSSIBLE. MEANWHILE SNOW IS POSSIBLE ON THE
NORTHERN SIDE OF THE PRECIPITATION SHIELD, GENERALLY ACROSS THE
CENTRAL PLAINS/MIDDLE MISSISSIPPI VALLEY AND OHIO VALLEY TOWARD THE
MID-ATLANTIC AND NORTHEAST, WITH SOME PLACES SEEING MULTIPLE
ROUNDS OF WINTRY WEATHER. SLEET AND FREEZING RAIN ARE POSSIBLE AS
WELL. MEANWHILE, THE WEST WILL SEE DRIER CONDITIONS EARLY NEXT WEEK
BEFORE AN ATMOSPHERIC RIVER RETURNS AROUND MIDWEEK. TEMPERATURE-
WISE, BELOW AVERAGE TEMPERATURES IN THE NORTHERN TIER ARE FORECAST
TO TREND COLDER AND SPREAD ACROSS THE CENTRAL U.S. AS THE WEEK
PROGRESSES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS SHOW GENERALLY GOOD AGREEMENT ON THE OVERALL PATTERN DURING
THE PERIOD BUT WITH DIFFERENCES IN THE SMALLER SCALE DETAILS THAT
WILL HAVE SENSIBLE WEATHER IMPLICATIONS. MODELS SHOW A WESTERN
ATLANTIC SURFACE LOW PRODUCING SNOW IN THE NORTHEAST AT THE START
OF THE PERIOD SUNDAY THAT QUICKLY PULLS AWAY TO THE NORTHEAST. IN
THE SOUTHERN TO EASTERN U.S. NEXT WEEK, THE PATTERN WILL BE
DOMINATED BY SMALL FRONTAL POSITION DIFFERENCES AND LOW PRESSURE
WAVES ALONG THE FRONT. THESE LEAD TO DIFFERENCES IN PRECIPITATION
TYPE AND AMOUNTS AND TIMING, BUT ARE RATHER UNPREDICTABLE THIS FAR
OUT.
IN THE WESTERN AND CENTRAL U.S., SEVERAL NORTHERN AND SOUTHERN
STREAM ENERGIES MOVING THROUGH THE TROUGH ARE MORE UNCERTAIN AS THE
PERIOD PROGRESSES. AFTER SEVERAL CMC RUNS SHOWED A TROUGH AXIS
ORIENTED TO THE SOUTHWEST IN THE EASTERN PACIFIC EARLY NEXT WEEK
UNLIKE OTHER GUIDANCE, THE 00Z RUN FINALLY ALIGNS BETTER WITH THE
CONSENSUS. BUT THERE REMAINS CONSIDERABLE SPREAD WITH A SHORTWAVE
DROPPING SOUTHWARD THROUGH THE NORTHERN SIDE OF THE TROUGH MONDAY-
TUESDAY AND ITS PIVOT EASTWARD. THIS RESULTS IN CONSIDERABLE QPF
DIFFERENCES ALONG THE WEST COAST BY TUESDAY AND WEDNESDAY,
INCLUDING THE TIMING OF PRECIPITATION ARRIVAL, AND MODELS LIKE THE
12Z ECMWF AND 18Z GFS FOCUSING HEAVIER QPF AMOUNTS IN SOUTHERN
CALIFORNIA BY MIDWEEK. EXPECT FURTHER CHANGES TO THE FORECAST WITH
THIS UNCERTAIN SYSTEM.
THE WPC FORECAST USED A BLEND OF THE DETERMINISTIC ECMWF/GFS/UKMET
EARLY IN THE PERIOD, AND GRADUALLY INCREASED THE PROPORTION OF
ENSEMBLE MEANS TO JUST OVER HALF BY THE LATE PERIOD GIVEN THE
INCREASE OF SPREAD IN INDIVIDUAL MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
THE PATTERN LOOKS TO BECOME INCREASINGLY FAVORABLE FOR RAIN ACROSS
PARTS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY TO
TENNESSEE VALLEY AND SOUTHEAST FOR EARLY TO MID-NEXT WEEK. LOCAL TO
WIDESPREAD HEAVY RAIN COULD BE A THREAT IN THESE AREAS. ON MONDAY,
MOISTURE AND INSTABILITY MAY POOL CENTERED IN ARKANSAS AND
TRAINING OF CONVECTION IS POSSIBLE GIVEN THE WEST-EAST ORIENTED
FRONTS. THUS A MARGINAL RISK SEEMS PRUDENT FOR THE DAY 5/MONDAY
ERO. ERO AREAS WILL LIKELY BE NEEDED IN THE SOUTHEAST TUESDAY-
WEDNESDAY ONCE THOSE HEAVY RAIN AREAS PHASE INTO THE ERO TIMEFRAME.
ON THE NORTHERN SIDE OF THE PRECIPITATION SHIELD, ROUNDS OF
POTENTIALLY DISRUPTIVE WINTRY PRECIPITATION ARE POSSIBLE NEXT WEEK.
THE FAVORED AREA FOR WINTER WEATHER WILL BE GENERALLY FROM THE
CENTRAL PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY, OHIO VALLEY,
CENTRAL APPALACHIANS, AND MID-ATLANTIC/NORTHEAST WHERE MOISTURE
OVERRUNNING SOUTHERN TIER FRONTS WILL INTERACT WITH COLD AIR.
CURRENTLY THE HIGHEST PROBABILITIES (50-70 PERCENT) FOR A QUARTER
INCH OF LIQUID EQUIVALENT SNOW/SLEET ARE IN PLACE ACROSS THE MID-
ATLANTIC TO SOUTHERN PARTS OF THE NORTHEAST FOR TUESDAY TO
WEDNESDAY MORNING, INCLUDING SOME OF THE LARGER I-95 METROPOLITAN
AREAS. MEANWHILE SLEET AND FREEZING RAIN ARE POSSIBLE IN BETWEEN
THE CHANCES FOR HEAVY RAIN TO THE SOUTH AND SNOW TO THE NORTH. STAY
TUNED FOR REFINEMENTS TO THE FORECAST AS THE PLACEMENT, AMOUNT,
AND TYPE OF PRECIPITATION REMAINS UNCERTAIN AT ANY INDIVIDUAL
LOCATION.
PRECIPITATION IS FINALLY FORECAST TO LESSEN IN SCOPE AND MAGNITUDE
IN THE WEST EARLY NEXT WEEK, WITH JUST SOME LIGHT AMOUNTS IN THE
PACIFIC NORTHWEST AND PARTS OF THE NORTHERN/CENTRAL ROCKIES. MODELS
VARY ON THE TIMING, STRENGTH, AND POSITIONING OF ANOTHER ROUND OF
PRECIPITATION ENTERING THE WEST NEXT WEEK WITH A POSSIBLE
ATMOSPHERIC RIVER. PRECIPITATION CHANCES GENERALLY LOOK TO INCREASE
TUESDAY AND ESPECIALLY WEDNESDAY FOR PARTS OF THE WEST COAST, BUT
STAY TUNED FOR POTENTIAL FORECAST CHANGES FOR THIS UNCERTAIN
SYSTEM.
COLDER THAN AVERAGE TEMPERATURES ARE FORECAST FOR NORTHWESTERN AND
NORTH-CENTRAL PARTS OF THE LOWER 48 THROUGH THE PERIOD. THE COLD
WILL BE ESPECIALLY PRONOUNCED ACROSS MONTANA AND NORTH DAKOTA INTO
MINNESOTA AS THE WORKWEEK BEGINS. BY MONDAY THROUGH MUCH OF THE
WEEK, LOWS ARE FORECAST TO BE IN THE -10S AND -20S, ALONG WITH SOME
BELOW ZERO HIGHS. COLDER THAN AVERAGE TEMPERATURES WILL SPREAD
SOUTH BEHIND A COLD FRONT NEXT WEEK, DISPLACING UNSEASONABLE WARMTH
THAT PERSISTS ACROSS THE SOUTHERN TIER INTO SUNDAY. WARMER THAN
AVERAGE TEMPERATURES SHOULD BE LIMITED TO FLORIDA AND THE ADJACENT
SOUTHEAST BY MIDWEEK.
TATE
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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