078
FXUS02 KWBC 090701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST FRI DEC 09 2022
VALID 12Z MON DEC 12 2022 - 12Z FRI DEC 16 2022
...MOUNTAIN/INLAND HEAVY SNOW/WIND THREAT INTO THE ROCKIES ON
MONDAY...
...MAJOR STORM SYSTEM TO BRING HEAVY SNOW/BLIZZARD CONDITIONS TO
NORTHERN-CENTRAL PLAINS WITH A HEAVY RAIN/SEVERE WEATHER THREAT
FOR SOUTHERN AREAS NEXT WEEK...
..OVERVIEW
RAIN AND THUNDERSTORMS WILL BE LIKELY ACROSS PARTS OF THE
SOUTHEAST ALONG A WAVY FRONTAL BOUNDARY, WHILE PERIOD OF RAIN/SNOW
MOVE THROUGH THE NORTHEAST AS A DEEP UPPER LOW ROTATES OFFSHORE
NEAR THE CANADIAN MARITIMES. THE MAIN STORY HOWEVER DURING THE
MEDIUM RANGE PERIOD CONTINUES TO FEATURE A MAJOR STORM SYSTEM
TRACKING ACROSS THE WEST AS THE PERIOD BEGINS MONDAY, SUPPORTING
WIDESPREAD AND POTENTIALLY SIGNIFICANT MOUNTAIN SNOWS ACROSS PARTS
OF THE INTERIOR WEST AND THE ROCKIES. BY TUESDAY AND BEYOND,
INTENSE CYCLOGENESIS IS EXPECTED TO OCCUR WITH INCREASING
CONFIDENCE IN A MAJOR STORM SYSTEM EMERGING INTO THE PLAINS. THIS
SYSTEM SHOULD BRING A WIDE ARRAY OF HAZARDS INCLUDING HEAVY
RAIN/SEVERE WEATHER TO THE SOUTH, AND HEAVY SNOW WITH BLIZZARD
CONDITIONS ACROSS PARTS OF THE NORTH-CENTRAL PLAINS AND INTO THE
UPPER MIDWEST AROUND MID WEEK NEXT WEEK WITH SOME CHANCE OF
FREEZING RAIN IN THE TRANSITION ZONE. THIS STORM SYSTEM SHOULD
TRACK STEADILY EASTWARD BRINGING A HEAVY RAIN THREAT TO PARTS OF
THE SOUTHEAST AND MID-ATLANTIC (WITH SOME SNOW POTENTIAL FARTHER
NORTH) LATER NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
A DEEP UPPER LOW AND SHORTWAVE TRACKING THROUGH THE CANADIAN
MARITIMES AND THE NORTHEAST ON MONDAY-TUESDAY SHOWS GOOD
CLUSTERING IN THE GUIDANCE, THOUGH WITH SOME LINGERING QUESTIONS
ON DETAILS. UPSTREAM, GUIDANCE CONTINUES TO AGREE FOR AN AMPLIFIED
TROUGH/CLOSED LOW OVER THE WEST TO DEEPEN WITH VIGOROUS SURFACE
CYCLOGENESIS INTO THE PLAINS MIDWEEK. THE GUIDANCE REMAINS WELL
CLUSTERED ON THE PARENT DEEP UPPER LOW TRACKING ACROSS THE CENTRAL
PLAINS ON WEDNESDAY TO THE MIDWEST BY FRIDAY. FOR THIS MID TO DEEP
MEDIUM RANGE TIME FRAME, THERE'S FAIRLY REMARKABLE AGREEMENT IN
THE SETUP AND GENERAL TRACK, WITH SOME LINGERING QUESTIONS ON
TIMING (CMC SEEMS TOO QUICK FOR THIS WRAPPED UP/DEEP OF A SYSTEM,
UKMET A LITTLE SLOWER). EITHER WAY, A GENERAL MODEL COMPROMISE
WEIGHTED TOWARDS THE AGREEABLE GFS AND ECMWF SEEMS REASONABLE
THROUGH DAY 5. BY LATER NEXT WEEK, THERE ARE SOME MORE DIFFERENCES
ESPECIALLY REGARDING TRACK/TIMING OF POSSIBLE COASTAL LOW
DEVELOPMENT OFF THE MID-ATLANTIC AS THE MAIN UPPER LOW SHIFTS INTO
THE MIDWEST. INCREASING CONTRIBUTIONS FROM THE ENSEMBLE MEANS
SEEMED REASONABLE BY THIS POINT, THOUGH STILL MAINTAINED AT LEAST
50 PERCENT DETERMINISTIC MODELS FOR ADDED SYSTEM DEPTH, WHICH
MAJORITY OF MODELS CONTINUE TO DEPICT A FAIRLY DEEP SYSTEM EVEN
THROUGH DAY 7. COMPARED TO PREVIOUS WPC CONTINUITY, THIS RESULTED
IN A SLIGHTLY SLOWER FRONTAL PROGRESSION ACROSS THE CENTRAL AND
EASTERN U.S., THOUGH THAT IS CONSISTENT WITH THE LATEST MODEL
TRENDS. A TREND TOWARDS THE ENSEMBLE MEANS LATER NEXT WEEK ALSO
HELPED RESOLVE SOME LARGER UNCERTAINTIES WITH ANOTHER UPPER LOW
OFF THE WEST COAST.
..WEATHER/HAZARD HIGHLIGHTS
THE SYSTEM ROTATING OVER THE NORTHEAST SHOULD CONTINUE TO BRING
SOME RAIN/SNOW TO PARTS OF THE REGION INTO MONDAY, WHILE FARTHER
SOUTH, A LINGERING WAVY FRONTAL BOUNDARY RESULTS IN SCATTERED RAIN
AND THUNDERSTORMS. AS THE MAIN UPPER TROUGH DIGS ACROSS THE WEST
ON MONDAY, AND SHIFTS EASTWARD THE REMAINDER OF THE WEEK, A WIDE
VARIETY OF HAZARDS ARE LIKELY ACROSS THE COUNTRY. HEAVY
PRECIPITATION IS IMMINENT ACROSS THE WEST THROUGH MONDAY, INTO
HIGHER ELEVATIONS OF THE GREAT BASIN AND ROCKIES. THEN AS THE
UPPER TROUGH/LOW APPROACHES THE PLAINS AND A SURFACE LOW
CONSOLIDATES AND DEEPENS, AMPLE MOISTURE WILL SPREAD AHEAD OF A
COLD FRONT TO PRODUCE SIGNIFICANT RAINFALL ACROSS THE LOWER/MIDDLE
MISSISSIPPI VALLEY AND VICINITY BEGINNING MONDAY AND ESPECIALLY BY
TUESDAY AND SHIFTING EAST WITH TIME. THE STORM PREDICTION CENTER
CONTINUES TO MONITOR AND HIGHLIGHT THE POTENTIAL FOR STRONG TO
SEVERE CONVECTION ACROSS THIS REGION AS WELL. ON THE BACKSIDE OF
THE LOW, COLD TEMPERATURES AND WRAP-BACK MOISTURE WILL SUPPORT
SIGNIFICANT SNOW/WINDS IN THE NORTHERN PLAINS/UPPER MIDWEST AS
SHOWN BY STEADILY INCREASING WPC WINTER WEATHER OUTLOOK
PROBABILITIES AS WELL AS AREAS OF ICE/FREEZING RAIN IN A
TRANSITION ZONE. THIS ALSO SHOWS SOME WINTRY WEATHER POTENTIAL
SPREADING ACROSS THE GREAT LAKES REGION AND NORTHEAST IN FAVORABLE
DOWNSTREAM THETA-E ADVECTION OVER A PRE-COOLED AIRMASS.
THE WEST SHOULD SEE BELOW NORMAL CONDITIONS THROUGH THE PERIOD,
WITH THE MOST WIDESPREAD READINGS OF AT LEAST 10-15F BELOW NORMAL
FOR HIGH TEMPERATURES AS THE DEEP UPPER TROUGH CROSSES THE REGION
FOR THE FIRST HALF OF NEXT WEEK. SOME OF THIS COLDER AIR SHOULD
SPILL INTO THE HIGH PLAINS BY NEXT TUESDAY-THURSDAY BEHIND THE
EXPECTED PLAINS STORM. ON THE OTHER HAND, SOUTHERN/EASTERN AREAS
WILL BE NEAR TO ABOVE NORMAL FOR TEMPERATURES. ANOMALIES WILL BE
GREATEST FOR MORNING LOWS, WITH SOME PLUS 15-25F ANOMALIES ACROSS
THE SOUTHERN TIER THROUGH MUCH OF THE PERIOD EXPANDING NORTHWARD
AT TIMES ACROSS THE MISSISSIPPI VALLEY. HIGHS ARE FORECAST TO BE
AROUND 10-15F ABOVE NORMAL FOR THE CENTRAL AND THEN EAST-CENTRAL
U.S., LOCALLY HIGHER.
SCHICHTEL/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
HAZARDS:
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT LAKES AND THE
UPPER MISSISSIPPI VALLEY, TUE-WED,
DEC 13-DEC 14.
- HEAVY PRECIPITATION ACROSS PORTIONS OF THE MID-ATLANTIC AND THE
NORTHEAST, SUN, DEC 11.
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,
CALIFORNIA, AND THE SOUTHWEST, SUN, DEC 11.
- HEAVY RAIN ACROSS PORTIONS OF THE MISSISSIPPI VALLEY, THE
CENTRAL/SOUTHERN APPALACHIANS, THE
TENNESSEE VALLEY, THE GREAT LAKES, THE MID-ATLANTIC, THE
SOUTHEAST, THE SOUTHERN PLAINS, AND THE
OHIO VALLEY, TUE-THU, DEC 13-DEC 15.
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL GREAT BASIN,
CALIFORNIA, THE NORTHERN ROCKIES, THE
NORTHERN GREAT BASIN, AND THE SOUTHWEST, SUN, DEC 11.
- HEAVY SNOW ACROSS PORTIONS OF THE SOUTHERN ROCKIES, THE CENTRAL
ROCKIES, THE CENTRAL GREAT BASIN,
AND THE SOUTHWEST, MON, DEC 12.
- HEAVY SNOW ACROSS PORTIONS OF THE CENTRAL PLAINS, THE GREAT
LAKES, THE UPPER MISSISSIPPI VALLEY,
AND THE NORTHERN PLAINS, MON-WED, DEC 12-DEC 14.
- SEVERE WEATHER ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY
AND THE SOUTHERN PLAINS, MON, DEC
12.
- SEVERE WEATHER ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY,
THE LOWER MISSISSIPPI VALLEY,
THE SOUTHERN PLAINS, AND THE TENNESSEE VALLEY, TUE, DEC 13.
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES 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
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