363
FXUS02 KWBC 031912
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
212 PM EST WED JAN 03 2024
VALID 12Z SAT JAN 06 2024 - 12Z WED JAN 10 2024
...MAJOR WINTER STORM TO BRING HAZARDOUS WEATHER ACROSS THE
APPALACHIANS/MID-ATLANTIC AND NORTHEAST THIS WEEKEND...
...ANOTHER MAJOR STORM TO BRING HEAVY RAIN/STRONG CONVECTION AND
GUSTY WINDS ACROSS THE SOUTH-CENTRAL U.S. AND INTO THE EAST EARLY
TO MIDDLE OF NEXT WEEK, WITH A HEAVY SNOW THREAT TO THE NORTH...
...DYNAMIC STORM SYSTEMS TO FOCUS COASTAL RAIN/INLAND HEAVY SNOW
THREATS OVER THE NORTHWEST/WEST THIS WEEKEND AND NEXT WEEK...
..OVERVIEW
AN EXTREMELY ACTIVE MEDIUM RANGE PERIOD REMAINS ON TAP WITH A
SERIES OF MAJOR STORM SYSTEMS IN THE FORECAST. A LEADING SYSTEM
MOVES INTO THE EAST THIS WEEKEND, WITH POTENTIAL FOR HEAVY RAIN
NEAR THE COAST AND HEAVY SNOW ACROSS THE APPALACHIANS AND INTERIOR
PORTIONS OF THE MID-ATLANTIC AND NEW ENGLAND WITH COASTAL STORM
DEVELOPMENT. IN ITS WAKE, A NEXT MAIN UPPER TROUGH DIGS INTO A
HIGHLY UNSETTLED WEST THIS WEEKEND AS WELL, FOCUSING WINTRY
THREATS FOR TERRAIN/MOUNTAIN SNOWS AND WINDS. DEEP CYCLOGENESIS
THAN REMAINS LIKELY ACROSS THE SOUTH-CENTRAL PLAINS BY MONDAY,
WITH IMPRESSIVE LEAD MOISTURE AND INSTABILITY RETURN TO FUEL
WIDESPREAD HEAVY RAINFALL/CONVECTION AND RUNOFF ISSUES ACROSS THE
SOUTH-CENTRAL TO EASTERN U.S. THROUGH NEXT MIDWEEK. THERE IS ALSO
A SIGNIFICANT SNOW/ICE THREAT TO THE NORTH OF THE DEEP LOW TRACK
FROM THE CENTRAL PLAINS TO THE MIDWEST/GREAT LAKES AND NORTHEAST
MONDAY-WEDNESDAY, ALONG WITH ENHANCED WINDS. ADDITIONAL DYNAMIC
SYSTEMS IN THE SERIES LOOK TO MOVE INTO THE PACIFIC NORTHWEST
EARLY NEXT WEEK BEFORE DIGGING ACROSS THE WEST INTO NEXT MIDWEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL AND ENSEMBLE SOLUTIONS CERTAINLY CONTINUE TO OFFER
UNCERTAINTIES WITH EMBEDDED SYSTEM DETAILS/FOCUS AND FLOW
INTERACTIONS, BUT WITH SOME IMPROVEMENT AND STEADFAST DEVELOPMENT
OF QUITE THE ACTIVE JANUARY STORM PATTERN TO IMPACT MUCH OF THE
NATION OVER THE NEXT WEEK. MODEL VARIANCES THOUGH SEEM REASONABLE
ENOUGH TO ALLOW FOR A COMPOSITE BLEND THAT PRODUCED DECENTLY
DEFINED AND CONSISTENT SYSTEM DEPICTIONS AND THREAT FOCI. THE WPC
MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A BLEND OF
THE GFS/ECMWF/UKMET/CANADIAN FOR SATURDAY INTO NEXT MONDAY BEFORE
MIXING IN SOME GEFS/ECMWF ENSEMBLE MEANS TO INCREASINGLY SMOOTH
THE LESS PREDICTABLE ROUGH EDGES WHILE STILL MAINTAINING
SUBSTANTIAL SYSTEM BREATH AND IMPACT POTENTIAL. WPC PRODUCT
CONTINUITY WAS REASONABLY WELL MAINTAINED IN THIS MANNER.
..WEATHER/HAZARDS HIGHLIGHTS
A MAJOR SURFACE LOW TRACKING OFF THE MID-ATLANTIC COAST SATURDAY
INTO SUNDAY CONTINUES TO SHOW AMPLE SNOW POTENTIAL TO THE NORTH OF
THE LOW, PRIMARILY FOR PORTIONS OF THE CENTRAL APPALACHIANS AND
INTERIOR MID-ATLANTIC AND NORTHEAST. THERE MAY BE A PERIOD OF
FREEZING RAIN/ICE AS WELL FOR PARTS OF/LEE OF THE CENTRAL
APPALACHIANS SATURDAY. CLOSER TO THE COAST, AND INCLUDING THE
MAJOR DC-NYC CORRIDOR THIS WEEKEND, THERE IS PLENTY OF UNCERTAINTY
REGARDING PRECIPITATION TYPE AND AMOUNTS, HIGHLY DEPENDENT ON THE
EXACT TRACK OF THE LOW AND AVAILABILITY OF SUFFICIENTLY COLD AIR
CONSIDERING LACK OF A CLASSIC COLD AIR WEDGE DUG DOWN OVER THE
EAST IN ADVANCE OF THE MAIN LOW. THERE IS A SUBSET OF GUIDANCE
SUGGESTING THESE MAJOR CITIES COULD SEE MODERATE TO HEAVY SNOW
ACCUMULATIONS, WHICH HAS NOT HAPPENED IN A QUITE A WHILE, BUT ALSO
AMPLE POTENTIAL FOR MORE MODEST ACCUMULATIONS AND COLD RAINS. A
MARGINAL RISK FOR FLASH FLOODING REMAINS ON THE DAY 4/SATURDAY
EXCESSIVE RAINFALL OUTLOOK, BUT WAS CONFINED MAINLY FOR THE
COASTAL CAROLINAS AND EASTERN MID-ATLANTIC GIVEN A OVERALL FASTER
PROGRESSION AND LACK OF SIGNIFICANT RAINFALL.
THE NEXT MAIN TROUGH INTO THE WEST WILL BRING EXPANDING COVERAGE
OF RAIN AND MOUNTAIN SNOWS ACROSS THE NORTHWEST AND INTO THE FOUR
CORNERS REGION THIS WEEKEND. THERE IS A DECENT SIGNAL FOR
MEANINGFUL MOUNTAIN SNOWS ACROSS PARTS OF THE CASCADES, SIERRA
NEVADA, AND INTERIOR MOUNTAIN RANGES/SOUTHERN ROCKIES. AS THE
PARENT TROUGH EJECTS INTO THE PLAINS, AN AREA OF LOW PRESSURE
LOOKS TO FORM AND DEEPEN AS IT TRACKS NORTHEASTWARD INTO THE
MISSISSIPPI VALLEY AND GREAT LAKES NEXT WEEK. THIS WILL TAP GULF
OF MEXICO MOISTURE TO FUEL WIDESPREAD MODERATE TO HEAVY RAINFALL
ACROSS MUCH OF THE MID/LOWER MISSISSIPPI VALLEY AND THE SOUTH ON
MONDAY WITH SOME SEVERE WEATHER POTENTIAL AS WELL ALONG THE
CENTRAL GULF COAST, PER THE LATEST FROM THE STORM PREDICTION
CENTER. RAIN WILL MOVE INTO THE EASTERN U.S. ON TUESDAY AND
DEPENDING ON SNOW ACCUMULATIONS ACROSS PARTS OF THE EAST EARLY IN
THE PERIOD, THIS COULD BRING AN INCREASED RISK FOR FLOODING DUE TO
EXCESSIVE RAIN AND SNOWMELT. A PROTRACTED PERIOD OF GUSTY WINDS
AROUND THE DEEP LOW LOOKS LIKELY AS WELL ACROSS THE EAST-CENTRAL
U.S. TO NORTHEASTERN U.S. AS THIS SYSTEM STRENGTHENS. THERE IS
ALSO AN INCREASING THREAT FOR A WIDESPREAD SWATH OF HEAVY SNOWS
AND ICE TO THE NORTH OF THE LOW FROM THE CENTRAL PLAINS TO THE
MIDWEST/GREAT LAKES THEN NORTHEAST. AS AFOREMENTIONED, ADDITIONAL
DYNAMIC SYSTEMS IN THE SERIES LOOK TO MOVE INTO THE PACIFIC
NORTHWEST EARLY NEXT WEEK BEFORE DIGGING ACROSS THE WEST INTO NEXT
MIDWEEK.
THIS WEEKEND ABOVE SEASONAL AVERAGE TEMPERATURES CAN BE EXPECTED
ACROSS THE FAR NORTHERN TIER STATES WITH ANOMALIES GENERALLY PLUS
5-15F FOR HIGHS, AND PERHAPS AS HIGH AS PLUS 15-25F FOR MORNING
LOWS OVER PARTS OF MINNESOTA/WISCONSIN. ABOVE NORMAL TEMPERATURES
ALSO LOOK TO RETURN TO THE SOUTHERN PLAINS/LOWER MISSISSIPPI
VALLEY AND EVENTUALLY THE EAST EARLY NEXT WEEK. THE SOUTHERN
TWO-THIRDS OF THE WEST WILL LIKELY HAVE BELOW NORMAL TEMPERATURES
LATE THIS WEEK, WITH SOME COOLER ANOMALIES AT LEAST 10F BELOW
NORMAL FOR HIGHS SPREADING ACROSS THE WEST INTO THE HIGH PLAINS BY
SUNDAY-TUESDAY AS UPPER TROUGHING MOVES OVER THE REGION. PARTS OF
THE NORTHWEST AND NORTHERN PLAINS SHOULD TREND BELOW NORMAL AS
WELL, WITH MODESTLY BELOW NORMAL TEMPERATURES ACROSS THE SOUTHERN
PLAINS/SOUTHEAST FOLLOWING PASSAGE OF THE STRONG COLD FRONT EARLY
NEXT WEEK.
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, 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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