290
FXUS02 KWBC 040641
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
141 AM EST THU JAN 04 2024
VALID 12Z SUN JAN 07 2024 - 12Z THU JAN 11 2024
...MAJOR WINTER STORM TO CONTINUE BRINGING HAZARDOUS WEATHER
ACROSS PARTS OF THE NORTHEAST INTO SUNDAY...
...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 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
WILL BE EXITING THE EAST ON SUNDAY, WITH SOME POTENTIAL FOR
LINGERING HAZARDOUS WEATHER ACROSS PARTS OF THE NORTHEAST. IN ITS
WAKE, A NEXT MAIN UPPER TROUGH WILL BE DIGGING THROUGH 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 GUSTY 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
THE LATEST GUIDANCE CONTINUES TO OFFER ABOVE AVERAGE AGREEMENT ON
THE LARGER SCALE PATTERN, BUT PLENTY OF UNCERTAINTIES IN THE
DETAILS OF EMBEDDED SYSTEMS AND FLOW INTERACTIONS. REGARDLESS,
THERE IS HIGH CONFIDENCE IN A VERY ACTIVE JANUARY STORM PATTERN
ACROSS MUCH OF THE NATION FOR AT LEAST THE NEXT WEEK. WITH THE
WEEKEND STORM EXITING THE EAST COAST BY THE START OF THE MEDIUM
RANGE PERIOD (SUNDAY), THE MAIN FOCUS WILL BE ON THE STORM LIKELY
TO DEVELOP AND IMPACT MUCH OF EASTERN HALF OF THE COUNTRY NEXT
WEEK. MODELS SHOW GOOD AGREEMENT ON A DEEPENING TROUGH ACROSS THE
WEST SUNDAY, BUT BEGIN TO HAVE SOME TIMING UNCERTAINTIES AS THE
SYSTEM KICKS OUT INTO THE PLAINS AND TRACKS ACROSS THE MIDWEST
MON-WED. ELSEWHERE, PLENTY OF UNCERTAINTY AS A SERIES OF
SHORTWAVES MOVES ACROSS THE NORTHWEST NEXT WEEK, WITH POTENTIAL
FOR ANOTHER LOW PRESSURE SYSTEM TO MOVE INTO THE NORTH-CENTRAL
U.S. NEXT WEDNESDAY-THURSDAY.
THE WPC MEDIUM RANGE PRODUCT SUITE FOR TONIGHT USED A BLEND OF THE
DETERMINISTIC GUIDANCE FOR SUNDAY-MONDAY, BEFORE INCORPORATING
SOME OF THE GEFS/ECENS ENSEMBLE MEANS TO HELP SMOOTH OUT THE
SMALLER SCALE DIFFERENCES. DID CONTINUE SOME LESSENING PARTS OF
THE DETERMINISTIC SOLUTIONS LATE PERIOD TO HELP MAINTAIN
REASONABLE SYSTEM DEFINITION. THIS APPROACH MAINTAINED VERY GOOD
CONTINUITY WITH THE PREVIOUS WPC FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
THE MAJOR SURFACE LOW BRINGING SNOW AND ICE TO PARTS OF THE
MID-ATLANTIC/NORTHEAST WILL BE EXITING THE EAST COAST BY SUNDAY,
BUT THERE COULD STILL BE SOME HAZARDOUS WEATHER ACROSS PARTS OF
NEW ENGLAND, INCLUDING MODERATE TO HEAVY SNOWS AND GUSTY WINDS.
THE NEXT MAIN TROUGH INTO THE WEST WILL BRING SOME RAIN AND
MOUNTAIN SNOWS ACROSS THE FOUR CORNERS REGION ON SUNDAY WITH A
DECENT SIGNAL FOR MEANINGFUL SNOW ACCUMULATIONS ACROSS PARTS OF
THE 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. GIVEN AMPLE MOISTURE AND
INSTABILITY, AND RAINFALL EXPECTED IN THE SHORT RANGE PERIOD, A
SLIGHT RISK WAS INCLUDED ON THE DAY 5 EXCESSIVE RAINFALL OUTLOOK
TONIGHT, WITH A BROAD MARGINAL FOR SURROUNDING AREAS ACROSS THE
DEEP SOUTH. RAIN WILL MOVE INTO THE EASTERN U.S. ON TUESDAY AND
DEPENDING ON SNOW ACCUMULATIONS ACROSS PARTS OF THE EAST THIS
WEEKEND, 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.
ADDITIONAL DYNAMIC SYSTEMS IN THE SERIES LOOK TO MOVE INTO THE
PACIFIC NORTHWEST EARLY NEXT WEEK WITH ROUNDS OF MODERATE TO HEAVY
RAINFALL EXPECTED FOR THE COASTAL RANGES AND FOOTHILLS OF THE
WA/OR CASCADES. GIVEN THE ONGOING WET PATTERN ACROSS THIS REGION
LATER THIS WEEK/THIS WEEKEND, A MARGINAL RISK WAS ADDED TO THE DAY
5/MONDAY EXCESSIVE RAINFALL OUTLOOK FOR THIS REGION. HEAVY SNOWS
ARE EXPECTED IN THE HIGHER TERRAIN OF THE CASCADES, WITH RAIN AND
MOUNTAIN SNOW ALSO EXTENDING INTO PARTS OF THE INTERIOR WEST
THROUGH WEDNESDAY.
TEMPERATURES SHOULD GENERALLY TREND COOLER ACROSS MUCH OF THE
WESTERN U.S. INTO NEXT WEEK AS MEAN TROUGHING REMAINS ANCHORED
OVER THE REGION. DAYTIME HIGHS 5-15 DEGREES ABOVE NORMAL ARE
EXPECTED SUNDAY-MONDAY WITH SOME SLIGHT MODERATION
TUESDAY-WEDNESDAY, BEFORE TRENDING EVEN COLDER NEXT THURSDAY, WITH
WIDESPREAD HIGHS 10-20 DEGREES BELOW NORMAL ACROSS INTERIOR
PORTIONS OF THE WEST AND EXTENDING INTO PARTS OF THE CENTRAL AND
NORTHERN PLAINS. AHEAD OF THE NEXT STORM SYSTEM IN THE CENTRAL
U.S. EARLY NEXT WEEK, TEMPERATURES ACROSS THE EAST WILL LIKELY BE
MODERATELY ABOVE NORMAL.
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, 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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