000
FXUS63 KBIS 091702
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1102 AM CST MON DEC 9 2013

.UPDATE...
ISSUED AT 1047 AM CST MON DEC 9 2013

WILL UPGRADE THE ADVISORY TO A BLIZZARD WARNING FOR THE WEST
CENTRAL...SOUTHWEST AND FAR SOUTH CENTRAL. ALSO ADDING ANOTHER
TIER OF COUNTIES INTO THE WINTER WEATHER ADVISORY...INCLUDING
EMMONS BURLEIGH AND SHERIDAN. EXAMINED MODEL SOUNDINGS AND SEE
STRONG POTENTIAL FOR 45 MPH WIND GUSTS WITH THE ALBERTA CLIPPER
ACROSS THE SOUTHWEST. ALSO...SUPERSATURATED WITH RESPECT TO ICE IN
THE DENDRITIC GROWTH ZONE FROM THE BOUNDARY LAYER TO 700 MB. WITH
THAT IN MINE SEE POTENTIAL TO GENERATE A BURST OF SNOWFALL WITH
THE SYSTEM. NOT MUCH MORE THAN 1 TO 2 INCHES BUT ADDING THE SNOW TO
THE WINDS AND SNOW ON GROUND SHOULD LOWER VISIBILITIES TO LESS THAN
A QUARTER MILE. THE ONLY NEGATIVE I SEE IS THE FACT THAT COLD
DENSE AIR IS IN PLACE..AND THIS COULD LIMIT THE TRANSFER OF
MOMENTUM. OTHERWISE...MOST INGREDIENTS ARE IN PLACE FOR A 3 TO 5
HOUR PERIOD OF BLIZZARD CONDITIONS ACROSS THE WEST CENTRAL AND
SOUTHWEST BEGINNING AROUND 3 AND EXTENDING INTO THE MID EVENING.
BLIZZARD CONDITIONS MAY TAKE A FEW MORE HOURS...AROUND 5 PM OR SO
TO REACH SIOUX COUNTY.

UPDATE ISSUED AT 638 AM CST MON DEC 9 2013

NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME.
ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING
MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY
THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20
BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY
CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY
TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT
SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18
UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER
WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN
AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST MON DEC 9 2013

THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND
CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING.

THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL
CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD
FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS
AFTERNOON.

OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL
INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE
EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW
ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A
WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND
EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A
BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH
NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY
FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST
WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING
SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE
STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC
LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE
MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS
WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH
PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE
POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED
SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA
AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE
HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING
MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES
TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE
MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA
MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH
AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE
EXPECTED TO BE THE STRONGEST.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 332 AM CST MON DEC 9 2013

THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING
SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW
CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC
ZONE OVER THE NORTHERN PLAINS.

CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC
TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE
MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD
WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND
PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS
INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE
DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE
SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO
DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO
TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME.

COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS
THE FORECAST AREA.

THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE.
SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW
PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH
PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE
AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH
DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN
ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH
HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1047 AM CST MON DEC 9 2013

MAIN HAZARD TO AVIATION WILL BE STRONG WINDS...AND BLIZZARD
CONDITIONS ACROSS THE SOUTHWEST AND WEST CENTRAL...IMPACTING
PRIMARILY KDIK...BUT KISN-KBIS WILL BE ION THE PERIPHERY. MAIN
TIMING WILL BE BETWEEN 3 PM AND MIDNIGHT. OUTSIDE OF THIS
AREA...MVFR TO OCNLY IFR CONDITIONS AFTER 21Z WILL BE FOUND IN
AREAS OF SNOW AND BLOWING SNOW.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR NDZ001>004-009>012-019>022-034-035-046.

BLIZZARD WARNING FROM 3 PM CST /2 PM MST/ THIS AFTERNOON TO
MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ017-018-031>033-040>045.

WIND CHILL ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ003>005-
011>013-022-023-025-036-037-047-048-050-051.

&&

$$

UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA