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000
FXUS63 KBIS 011249
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
649 AM CST SUN DEC 1 2013

.SYNOPSIS...

ISSUED AT 445 AM CST SUN DEC 1 2013

A BROAD...POSITIVELY TILTED MIDDLE/UPPER LEVEL TROUGH DIGGING INTO
THE PACIFIC NORTHWEST WILL EJECT SEVERAL SHORTWAVES INTO THE
NORTHERN PLAINS OVER THE NEXT FEW DAYS. MODEL AGREEMENT ON THE
EVOLUTION AND PROGRESSION OF THIS FULL LATITUDE TROUGH HAS BEEN
POOR...BUT CONSENSUS IS BEGINNING TO DEVELOP.

&&

.UPDATE...

ISSUED AT 649 AM CST SUN DEC 1 2013

INHERITED FORECAST REMAIN MOSTLY ON TRACK. MID LEVEL S/WV OVER FAR
SOUTHERN SASKATCHEWAN AND ASSOCIATED FRONTAL BOUNDARY OVER WESTERN
NORTH DAKOTA GENERATING A WINTRY MIX OF PRECIPITATION WEST OF
HIGHWAY 83 TO THE MONTANA BORDER. BOTH KHEI AND KISN HAVE REPORTED
UNKNOWN PRECIP THIS MORNING. MIXED PRECIPITATION SHOULD BECOME ALL
SNOW AS IT MOVES INTO CENTRAL NORTH DAKOTA WITH A COLDER THERMAL
PROFILE BELOW FREEZING. HAVE HAD REPORTS OF ICY ROAD CONDITIONS
NORTHWEST AND WILL THROW OUT A FREEZING RAIN ADVISORY FOR THIS
MORNING ACROSS MY 5 NORTHWEST COUNTIES.


&&

.SHORT TERM...(TODAY AND TONIGHT)

ISSUED AT 445 AM CST SUN DEC 1 2013

THERE ARE SEVERAL HAZARDS PRESENTING FORECAST CHALLENGES OVER THE
NEXT 24 HOURS.

FOG NORTHEAST OF A LINE FROM KENMARE TO OAKES HAS
HELD ON A BIT LONGER THAN EXPECTED. THIS IS DESPITE THE ADVECTION
OF MIDDLE LEVEL CLOUDS. VISIBILITIES SHOULD CONTINUE TO IMPROVE
OVER THE NEXT FEW HOURS.

AN AREA OF LIGHT FREEZING RAIN AND SNOW OVER NORTHEASTERN MONTANA
IS FORECAST TO SLIDE EASTWARD TODAY AND EXPAND/INTENSIFY. BY
MID MORNING...BUFKIT SOUNDINGS FROM THE 00 UTC NAM/GFS SUPPORT
ONLY SNOW EXCEPT OVER THE FAR SOUTHWESTERN COUNTIES. ACCUMULATIONS
WILL BE PRIMARILY IN THE FORM OF SNOW...AND SHOULD BE LESS THAN 2
INCHES...AT LEAST ACCORDING TO THE 00 UTC ECMWF/GFS/NAM/GEM GLOBAL.

ANOTHER APPROACHING SHORTWAVE WILL FORCE OVERRUNNING AND
ASSOCIATED LIGHT TO MODERATE PRECIPITATION TONIGHT. THERMAL
PROFILES SUPPORT A WINTRY MIX ACROSS THE SOUTHWEST...WITH SNOW
ELSEWHERE. AT PRESENT...IT APPEARS THAT UP TO 0.05 INCH OF GLAZE
IS POSSIBLE ACROSS SOUTHWESTERN COUNTIES. NORTHEAST OF
DICKINSON...THE ABSENCE OF FREEZING RAIN SHOULD LIMIT IMPACTS TO
THOSE TYPICALLY ASSOCIATED WITH ALL SNOW. THERE WILL PROBABLY BE A
SHORT BREAK BEFORE THE HEAVIER PRECIPITATION ASSOCIATED WITH
THE PRIMARY SURFACE LOW BEGINS. THIS IS DISCUSSED BELOW.

.LONG TERM...(MONDAY THROUGH SATURDAY)

ISSUED AT 445 AM CST SUN DEC 1 2013

UNCERTAINTY DECREASING AND CONFIDENCE GOING UP ON THE POTENTIAL FOR
SEVERE WINTER WEATHER ACROSS THE NORTHERN PLAINS THROUGH THE LONG
TERM PERIOD. LATEST 00Z MODELS HAVE CONTINUED THE TREND TOWARDS A
CONSENSUS. NEAR SEAMLESS AGREEMENT ON THE LEAD WAVE FOR
MONDAY-MONDAY EVENING. FOR MONDAY NIGHT THROUGH WEDNESDAY...THE
SPREAD AMONGST MODELS HAS DECREASED SIGNIFICANTLY...BUT THERE
REMAINS TIMING AND PLACEMENT ISSUES ON SURFACE AND MID LEVEL
FEATURES. HAVE BASED THE FORECAST ON A 75% 00Z ECMWF/25% 00Z GFS
BLEND.

UPPER LEVEL LOW PRESSURE TRACKING SLOWLY SOUTHWARD THIS MORNING
ALONG THE BRITISH COLUMBIA COAST. A POTENT LEAD SHORT WAVE
ORIGINATING WITH THE UPPER LOW WILL EJECT EAST-SOUTHEAST TODAY
ACROSS THE ROCKIES AND INTO THE NORTHERN PLAINS EARLY MONDAY
MORNING. WILL HAVE ONGOING PRECIPITATION ACROSS MY NORTH AND EAST AT
THE ONSET OF THE LONG TERM PERIOD 12Z MONDAY ASSOCIATED WITH THIS
FEATURE WITH MOISTURE WRAPPING AROUND LOW PRESSURE CENTERED OVER
WESTERN SOUTH DAKOTA. QPF UP TO A QUARTER OF AN INCH...POSSIBLY AS
HIGH AS FOUR TENTHS...IS FORECAST ACROSS NORTH CENTRAL ND AND INTO
THE TURTLE MOUNTAINS...WITH 0.1 TO 0.2 INCHES NORTHWEST AND ACROSS
THE JAMES RIVER BASIN. MAY SEE PARTIAL CLEARING SOUTHWEST IN THE
S/WV`S WAKE MONDAY MORNING BEFORE CLOUDING BACK UP MONDAY
AFTERNOON. WILL MAINTAIN A CHANCE FOR MIXED PRECIPITATION
SOUTHWEST INTO THE SOUTH CENTRAL ON THE TRAILING EDGE OF
PRECIPITATION WHERE A WARM POCKET OF AIR WILL BE NEAR A WARM
FRONT. SFC TEMPS WILL BE THE DECIDING FACTOR. MORE OF A RAIN/SNOW
MIX OR ALL RAIN WITH SFC TEMPERATURES WARMING TO ABOVE FREEZING
EARLY TO MID MORNING. CANNOT RULE OUT A SNOW/SLEET MIX BEFORE THIS
WARMING TAKES PLACE. THE CHANCE FOR MIXED PRECIPITATION WILL END
MONDAY EVENING AS CAA OVERTAKES THE STATE. ADVISORY LEVEL SNOWFALL
TOTALS WILL BE POSSIBLE MONDAY MORNING INTO MONDAY EVENING ACROSS
MY NORTHERN COUNTIES ALONG THE HIGHWAY 2 CORRIDOR TO THE CANADIAN
BORDER. OPTED TO NOT ISSUE HEADLINES WITH THIS FORECAST PACKAGE
FOR THIS LEAD S/WV MONDAY DAYTIME IN ORDER TO FOCUS ON THE BIGGER
THREAT MID-WEEK.

MODELS TRENDING TOWARDS A CONSENSUS MONDAY NIGHT THROUGH
WEDNESDAY...ALTHOUGH NOT THERE JUST YET. STRONG S/WV/CLOSED LOW IS
DEPICTED BY THE LATEST GFS/ECMWF TO MOVE ACROSS THE DAKOTAS MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH AN AREA OF MODERATE TO HEAVY SNOW
WRAPPING AROUND A SURFACE TROUGH AND UNDERNEATH THE SYSTEMS TROWAL.
LATEST GUIDANCE PUTS THE AREA OF HEAVY SNOW OVER MUCH OF THE CWA.
DIFFERENCES IN TIMING AND SNOW AMOUNTS REMAIN...WITH THE 00Z GFS
STILL FASTER BUT WITH HEAVIER PRECIP...AND THE 00Z ECMWF SLOWER AND
NOT AS WET. THE 06Z GFS RECENTLY CAME IN...AND SLOWED DOWN CLOSER TO
THE 00Z EC...AND HAS ALSO REMAINED WET WITH OVER AN INCH OF QPF
FORECAST FOR SOME AREAS. STILL TOO EARLY TO SPECIFY SNOWFALL
AMOUNTS...BUT COULD EASILY SEE SIX INCHES OR MORE MANY LOCATIONS
THROUGH WEDNESDAY BASED ON MODEL QPF AND HPC MEAN SNOW RATIOS
APPROACHING 12/18:1. BOTH MODELS GENERATE STRONG WINDS ON THE
BACKSIDE OF THE SURFACE LOW LIKELY PRODUCING BLOWING AND DRIFTING
SNOW IF ON THE GROUND OR FALLING. ENOUGH POTENTIAL IS NOW PRESENT
TO ISSUE A WINTER STORM WATCH MONDAY EVENING THROUGH WEDNESDAY
AFTERNOON.

ADDITIONAL WINTER WEATHER HEADLINES FOR WIND CHILLS WILL LIKELY BE
NEEDED THURSDAY AND INTO THE WEEKEND AS ARCTIC AIR TAKES UP
RESIDENCE ACROSS THE NORTHERN PLAINS. FORECAST HIGHS THURSDAY
THROUGH SUNDAY ARE IN THE SINGLE DIGITS ABOVE OR BELOW ALONG WITH
NIGHTTIME LOWS SUBZERO...POSSIBLY COLDER THAN 20 BELOW. RESULTANT
WIND CHILLS WILL EASILY RANGE 20-30 BELOW...WITH 45 BELOW VALUES
CURRENTLY FORECAST NORTH CENTRAL FRIDAY NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)

ISSUED AT 445 AM CST SUN DEC 1 2013

LIFR CONDITIONS AT KJMS/KMOT WILL GRADUALLY IMPROVE OVER THE NEXT
FEW HOURS. CEILINGS SHOULD REMAIN IN THE 100 TO 200 FT RANGE
UNTIL AROUND 13Z. AN ASSORTMENT OF PRECIPITATION TYPES WILL IMPACT
VISIBILITIES AT KISN/KDIK/KBIS/KMOT TODAY.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR NDZ001>005-009>013-017>023-025-031>037-040>048-050-
051.

FREEZING RAIN ADVISORY UNTIL NOON CST TODAY FOR NDZ001-002-009-
010-017.

&&

$$

UPDATE...NH
SYNOPSIS...SCHECK
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...SCHECK