000
FXUS63 KBIS 062048
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
248 PM CST FRI DEC 6 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 239 PM CST FRI DEC 6 2013

ARCTIC AIR FIRMLY IN PLACE TODAY THROUGH SATURDAY AS TEMPERATURES
REMAIN BELOW ZERO ACROSS THE WEST AND CENTRAL. DIMINISHED WINDS
DEEP SNOW COVER AND AND THE CENTER OF THE ARCTIC HIGH MOVING
THROUGH SOUTHWEST NORTH DAKOTA TONIGHT SHOULD ALLOW OVERNIGHT LOWS
TO FALL INTO THE 20S BELOW ZERO. EVEN A MODEST AMOUNT OF WIND WILL
RESULT IN WIND CHILLS COLDER THAN 40 BELOW ACROSS THE NORTH
C=SOUTH CENTRAL AND EAST. ISSUED A WIND CHILL WARNING MAINLY ALONG
AND NORTH AND EAST OF LAKE SAKAKAWEA AND THE MISSOURI RIVER
VALLEY. SOME CLOUDS...AND LIGHTER WINDS ACROSS THE SOUTHWEST SHOULD
HOLD THE WIND CHILLS IN THE ADVISORY CATEGORY. THERE WILL PROBABLY
BE FURTHER ADVISORIES SATURDAY NIGHT INTO SUNDAY...ESPECIALLY
NORTH. WILL CONCENTRATE TO ION THE MOST HAZARDOUS ASPECTS OF THE
ARCTIC AIR TONIGHT AND SATURDAY FIRST.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 239 PM CST FRI DEC 6 2013

THE LONG TERM BEGINS WITH A BRIEF PHASING OF THE NORTHERN/SOUTHERN
STREAMS SUNDAY...FOLLOWED BY THE NORTHERN STREAM TAKING FIRM CONTROL
AGAIN MONDAY THROUGH WEDNESDAY. FOR THURSDAY AND FRIDAY...A NEAR
ZONAL FLOW IS EXPECTED AS THE COLDEST OF THE ARCTIC AIR RETREATS
NORTH.

FOR SATURDAY NIGHT AND SUNDAY...CLOUDS WILL THICKEN AND LOWER ACROSS
THE SOUTH SATURDAY NIGHT WITH LIGHT SNOW FORECAST TO DEVELOP ALONG
AN INVERTED SURFACE TROUGH WHICH EXTENDS FROM COLORADO INTO
SOUTHERN NORTH DAKOTA. QPF AMOUNTS REMAIN LIGHT WITH A COUPLE
HUNDERETHS. WITH SNOW RATIOS AT 20 TO 1...EXPECT THE POTENTIAL FOR
AROUND A HALF INCH OF SNOW...ALONG AND SOUTH OF INTERSTATE 94
THROUGH SUNDAY AFTERNOON. THE NORTH WILL REMAIN DRY BUT VERY COLD.
EXPECTING A WIND CHILL HEADLINE/ADVISORY FOR THE NORTH INTO SUNDAY
MORNING. THE CENTRAL AND SOUTH WILL BE UNDER THE INFLUENCE OF CLOUDS
AND INCREASING POTENTIAL FOR LIGHT SNOW...THUS WILL NOT SEE WIND
CHILL CRITERIA BEING MET CENTRAL AND SOUTH FOR SATURDAY NIGHT INTO
SUNDAY MORNING.

FOR SUNDAY NIGHT...DRY BUT VERY COLD WITH WIND CHILL VALUES BETWEEN
25 AND 39 BELOW ZERO...WHICH WILL LIKELY NECESSITATE ANOTHER WIND
CHILL ADVISORY FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA.

FOR MONDAY INTO MONDAY NIGHT...AN ALBERTA CLIPPER REMAINS POISED TO
SWEEP THROUGH MONDAY AFTERNOON INTO MONDAY NIGHT. STRONG H85 WINDS
OF 50KT WILL ACCOMPANY THE CLIPPER. HOW MUCH OF THIS MOMENTUM WILL
TRANSLATE TO THE SURFACE IS STILL UNKNOWN. GFS SOUNDINGS INDICATE AN
ISOTHERMAL LAYER JUST ABOVE THE SURFACE...AND AN ADIABATIC LAPSE
RATE IS NOT SEEN UNTIL FARTHER UP IN THE SOUNDING. THUS THERE MAY BE
A DISCONNECT WITH LINKING UP TO THESE STRONGEST WINDS. CONCUR WE
WILL HAVE WINDS BETWEEN 20 AND 35 MPH WITH GUSTS TO 40 MPH...WHICH
WILL PRODUCE BLOWING AND DRIFTING SNOW...BUT NOT READY TO GO WITH
ANYTHING MUCH HIGHER THAN THAT AT THIS TIME. HAVE COLLABORATED WITH
NEIGHBORING OFFICES AND INCREASED WINDS BUY 5KT OVER THE ALLBLEND.
WILL AWAIT FUTURE RUNS BEFORE MAKING ANY OTHER CHANGES. DO EXPECT
LIGHT SNOW TO DEVELOP IN THE MORNING ACROSS THE NORTHWEST AND THEN
SPREAD SOUTHEAST IN THE AFTERNOON/EVENING. BLOWING/DRIFTING SNOW
WILL COMMENCE MONDAY AFTERNOON THROUGH MONDAY NIGHT. A SPECIAL
WEATHER STATEMENT OR POSSIBLE WINTER WEATHER ADVISORY MAY BE NEEDED
IN THE NEXT DAY OR TWO. THE LIGHT SNOW WILL DIMINISH MONDAY NIGHT.
NEW SNOWFALL ACCUMULATIONS SHOULD RANGE FROM A HALF INCH UP TO ONE
INCH MONDAY INTO MONDAY NIGHT. IN ADDITION...WE WILL LIKELY NEED WIND
CHILL HEADLINES LATE MONDAY NIGHT INTO TUESDAY MORNING FOR THE NORTH
AND EXTENDING INTO THE JAMES RIVER VALLEY WITH READINGS BETWEEN 25
AND 35 BELOW ZERO.

FOR TUESDAY AND WEDNESDAY...NORTHWEST FLOW ALOFT WITH A 1040MB
SURFACE HIGH WILL SLIDE ACROSS NORTH DAKOTA. GENERALLY A DRY AND
COLD PATTERN DURING THIS TIME. WIND CHILL TEMPERATURES OF 25 TO 35
BELOW ZERO ARE FORECAST ACROSS THE NORTH...AND INTO THE JAMES RIVER
VALLEY.

FOR THURSDAY AND FRIDAY...WARM AIR ADVECTION PROCESSES WILL ALLOW FOR THE
POTENTIAL OF LIGHT SNOW MAINLY ACROSS THE NORTH AND INTO THE TURTLE
MOUNTAINS THURSDAY. HIGH TEMPERATURES THURSDAY WILL RANGE BETWEEN 15
AND 28 DEGREES ABOVE ZERO THURSDAY. HOWEVER THIS WILL BE SHORT LIVED
AS ANOTHER SURGE OF COLD AIR ADVECTION FRIDAY...WITH HIGHS FORECAST
FROM ZERO TO 15 ABOVE. NORTHWEST FLOW FRIDAY MAY ALLOW ANOTHER
SYSTEM TO PRODUCE A CHANCE OF SNOW FRIDAY INTO FRIDAY NIGHT. THE GFS
AND ALLBLEND BOTH ADVERTISE THIS...BUT THE ECMWF IS DRY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 239 PM CST FRI DEC 6 2013

VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD. THE MAIN
HAZARD TO AVIATION WILL BE THE FRIGID TEMPERATURES AND DANGEROUS
WIND CHILLS ACROSS WEST AND CENTRAL NORTH DAKOTA. WIND CHILLS IN
THE 30S BELOW SOUTHWEST TO AS LOW AS 45 BELOW NORTH AND EAST WILL
CREATE DANGEROUS WEATHER CONDITIONS TO ANYONE CAUGHT WITH OUT
ADEQUATE COVERING.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING UNTIL 1 PM CST SATURDAY FOR NDZ001>005-
009>013-017>023-025-034>037-046>048-050-051.

WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ SATURDAY FOR
NDZ031>033-040>045.

&&

$$

SHORT TERM...WAA
LONG TERM...KS
AVIATION...WAA