560
FXUS02 KWBC 210658 AAC
PMDEPD
EXTENDED FORECAST DISCUSSION...UPDATED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 AM EDT THU MAR 21 2024
VALID 12Z SUN MAR 24 2024 - 12Z THU MAR 28 2024
***LATE SEASON WINTER STORM FOR THE DAKOTAS AND INTO MINNESOTA AND
WISCONSIN SUNDAY AND INTO MONDAY***
..GENERAL OVERVIEW
A STRONG LOW PRESSURE SYSTEM WILL BE DEVELOPING ACROSS THE CENTRAL
PLAINS AND THEN CROSSING THE UPPER MIDWEST GOING INTO THE BEGINNING
OF NEXT WEEK, IN RESPONSE TO AN AMPLIFYING UPPER LEVEL TROUGH OVER
THE ROCKIES. THIS WILL RESULT IN HEAVY SNOW NORTHWEST OF THE LOW,
AND NUMEROUS SHOWERS AND THUNDERSTORMS AHEAD OF THE COLD FRONT
ACROSS THE SOUTH-CENTRAL STATES. A SECOND SURFACE LOW IS LIKELY TO
DEVELOP OVER THE SOUTHEAST U.S. BY NEXT THURSDAY AND RESULT IN
RENEWED PROSPECTS FOR ADDITIONAL RAIN FOR THIS REGION. MEANWHILE, A
LOW PRESSURE SYSTEM FROM THE PACIFIC IS PROGGED TO MOVE INLAND
ACROSS THE NORTHWESTERN U.S. AND RESULT IN ADDITIONAL RAIN AND
MOUNTAIN SNOW FOR MID-WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE NOW HAS A GOOD OVERALL DEPICTION ON THE
EXPECTED EVOLUTION OF THE CENTRAL U.S. LOW PRESSURE SYSTEM, AND
THERE HAS BEEN A TREND FOR THE LOW TO LIFT OUT FARTHER NORTH INTO
SOUTHERN CANADA COMPARED TO EARLIER MODEL RUNS. THE UKMET STILL
STRAYS SOME FROM THE MODEL CONSENSUS WITH THE LOW OFF THE EAST
COAST ON SUNDAY, SO IT WAS NOT FAVORED AS A RESULT SINCE IT HAD
LITTLE IN THE WAY OF ENSEMBLE SUPPORT. MODEL AGREEMENT HAS
IMPROVED FOR THE STORM SYSTEM REACHING THE PACIFIC NORTHWEST LATE
IN THE FORECAST PERIOD.
THE WPC FRONTS/PRESSURES FORECAST WAS PRIMARILY DERIVED FROM A
CMC/GFS/ECMWF BLEND THROUGH MONDAY, FOLLOWED BY GRADUALLY
INCREASING PERCENTAGES OF THE ENSEMBLE MEANS THROUGH THURSDAY WHILE
USING SOME PREVIOUS WPC CONTINUITY THROUGH WEDNESDAY.
..WEATHER/HAZARDS HIGHLIGHTS
ON SUNDAY, A MARGINAL RISK AREA FOR EXCESSIVE RAINFALL IS PLANNED
FOR PORTIONS OF THE CENTRAL PLAINS WITH A CORRIDOR OF HEAVIER RAIN
LIKELY DEVELOPING FROM NORTHERN KANSAS TO EASTERN NEBRASKA AS A
STRONG SURFACE LOW IS FORECAST TO DEVELOP IN THE LEE OF THE
ROCKIES. THE LOW THEN TRACKS TOWARDS THE UPPER MIDWEST BY MONDAY
MORNING AND BECOMES THE DRIVER FOR A BIG LATE SEASON WINTER STORM.
THERE CONTINUES TO BE AN UPWARD TREND FOR SIGNIFICANT SNOWFALL
ACCUMULATIONS (8"+) ACROSS NORTHERN SOUTH DAKOTA, SOUTHERN NORTH
DAKOTA, CENTRAL MINNESOTA, AND NORTHWESTERN WISCONSIN, AS THIS
REGION WILL BE ON THE COLDER SIDE OF THE LOW WITH A DEFORMATION
ZONE DEVELOPING, AND PRODUCING BANDS OF HEAVIER WET SNOW WITH GUSTY
WINDS. THERE MAY ALSO BE A SWATH OF POTENTIALLY IMPACTFUL MIXED
PRECIPITATION, INCLUDING SOME FREEZING RAIN, MOST LIKELY TO THE
SOUTHEAST OF THE HEAVY SNOW SWATH FROM EASTERN NEBRASKA TO
NORTHWEST IOWA AND INTO SOUTHERN MINNESOTA. TIMING/TRACK
UNCERTAINTY MAY CHANGE THE EVENTUAL LOCATION OF THE IMPACTFUL
WINTER WEATHER, BUT THE RISK FOR DISRUPTIONS TO DAILY LIFE AND
HAZARDOUS TRAVEL IS LIKELY.
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS, SOME OF WHICH COULD
BE STRONG TO SEVERE, CAN BE EXPECTED IN THE WARM SECTOR OF THE
SYSTEM, BEGINNING FROM THE SOUTHERN PLAINS SUNDAY, AND THEN
SPREADING EASTWARD TO THE DEEP SOUTH ON MONDAY WHERE A MARGINAL
RISK AREA IS PLANNED FOR DAY 5. THERE ARE STILL QUESTION MARKS
ABOUT HOW MUCH INSTABILITY WILL EXIST AHEAD OF THE FRONT AS THE
SYSTEM PROGRESSES EASTWARD, EVEN THOUGH THE KINEMATIC ENVIRONMENT
WILL BE MORE FAVORABLE FOR POTENTIAL SEVERE WEATHER. NONETHELESS, A
QUASI-LINEAR CONVECTIVE SYSTEM (QLCS) IS EVIDENT ON THE LATEST GFS
AND ECMWF RUNS. THE STORMY WEATHER THEN REACHES THE FLORIDA
PANHANDLE AND PORTIONS OF ALABAMA AND GEORGIA ON TUESDAY WITH A
SECONDARY LOW LIKELY DEVELOPING OVER THE NORTHERN GULF.
IN TERMS OF TEMPERATURES, IT WILL FEEL MORE LIKE JANUARY ACROSS THE
WESTERN HIGH PLAINS FROM WESTERN KANSAS TO MONTANA AND THE DAKOTAS
IN THE WAKE OF THE STRONG COLD FRONT. HIGHS WILL ONLY BE IN THE 20S
AND 30S FOR THESE AREAS ON MONDAY, BUT A MODERATING TREND WILL
COMMENCE GOING INTO THE MIDDLE OF THE WEEK, EVEN THOUGH MONTANA AND
NORTH DAKOTA WILL STILL REMAIN CHILLY BY LATE MARCH STANDARDS.
WARMER WEATHER LIKELY MAKES A RETURN TO MUCH OF THE SOUTH-CENTRAL
U.S. BY NEXT WEDNESDAY AND THURSDAY.
HAMRICK
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page