000
FXUS63 KBIS 040404
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1004 PM CST TUE DEC 3 2013

.UPDATE...
ISSUED AT 947 PM CST TUE DEC 3 2013

ONLY MINOR CHANGES TO TEMPERATURE TRENDS FOR THE LATE EVENING
UPDATE. OPTED TO LEAVE THE ADVISORY IN PLACE ACROSS THE FAR
NORTHWEST COUNTIES FOR SEVERAL REASONS: LIGHT SNOW IS STARTING TO
SPREAD INTO THE WILLISTON AND STANLEY AREAS AND SHORT RANGE MODELS
INDICATE ADDITIONAL LIGHT QPF OVERNIGHT...LINGERING BLOWING AND
DRIFTING SNOW...AND FINALLY WIND CHILLS EXPECTED TO DROP AROUND 25
BELOW ZERO OVERNIGHT. ELSEWHERE...ADVISORY AND WARNING HEADLINES
CONTINUE WITH NO CHANGES. STEADY SNOW EXPECTED TO CONTINUE
OVERNIGHT AND GRADUALLY TAPER OFF FROM WEST TO EAST THROUGH THE
DAY ON WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 315 PM CST TUE DEC 3 2013

AN UPPER LEVEL LOW CONTINUES TO SWIRL OVER WESTERN MONTANA THIS
AFTERNOON. MOISTURE CONTINUES TO BE DRAWN NORTHWARD OVER MOST OF
THE STATE AHEAD OF THIS FEATURE...GENERATING LIGHT TO MODERATE
SNOW OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. GENERALLY 3-5
INCHES HAVE BEEN REPORTED OVER SOUTHWESTERN NORTH DAKOTA SO
FAR...WITH MORE SNOW FORECAST TO CONTINUE OVERNIGHT THROUGH
WEDNESDAY.

AS THE UPPER LEVEL LOW SLOWLY MOVES EAST THROUGH WEDNESDAY
NIGHT...SNOW WILL CONTINUE OVER THE NORTHERN PLAINS. THE MEDIUM
RANGE MODELS HAVE SLOWED THE PROGRESSION OF THE LOW AND ARE IN A
LITTLE BETTER AGREEMENT WITH THE SNOW INTENSITY AND PLACEMENT OVER
NORTH DAKOTA THROUGH WEDNESDAY NIGHT. GIVEN THE LIGHT TO MODERATE
INTENSITY AND SLOW DURATION OF THE EVENT...6 INCH STORM TOTALS
WILL PROBABLY NOT BE SEEN SOUTHWEST UNTIL AFTER MIDNIGHT TONIGHT.
AROUND 6 INCH STORM TOTALS WILL LIKELY BE ACHIEVED OVER SOUTH
CENTRAL AND SOUTHEASTERN NORTH DAKOTA BY MID TO LATE DAY
WEDNESDAY. SURFACE HIGH PRESSURE NOSING INTO NORTHERN NORTH DAKOTA
SHOULD KEEP SNOW AMOUNTS IN THE 2 TO 4 INCH RANGE NEAR THE
CANADIAN BORDER.

EVEN THOUGH THE 12Z MODELS ARE TRENDING A LITTLE SLOWER WITH SNOW
TAPERING OFF LATE WEDNESDAY...ADDITIONAL SNOWFALL AMOUNTS
WEDNESDAY NIGHT SHOULD REMAIN LESS THAN ONE-HALF AN INCH. GIVEN
THE EXPECTED RELATIVELY LIGHT SNOW AMOUNTS WEDNESDAY
NIGHT...MAINTAINED THE CURRENT AREAL AND TEMPORAL RESOLUTION OF
THE WINTER STORM WARNING AND WINTER WEATHER ADVISORY. THE NEXT
WEATHER ISSUE WILL BE THE DANGEROUSLY COLD WIND CHILLS THURSDAY
AND BEYOND. SEE DISCUSSION BELOW FOR MORE DETAILS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 315 PM CST TUE DEC 3 2013

THE MAIN FORECAST CONCERNS IN THE EXTENDED PERIOD ARE FRIGID
TEMPERATURES AND RESULTING HIGHLIGHTS. WILL UTILIZE A MODEL BLEND
WITH PERSISTENCE FOR WEATHER ELEMENTS.

BY THE TIME WE REACH THE EXTENDED PERIOD (THURSDAY) ARCTIC AIR HAS
SETTLED ACROSS THE NORTHERN PLAINS AND SOUTHERN PRAIRIE PROVINCES OF
CANADA. THE UPPER LEVEL LOW CIRCULATION ASSOCIATED WITH THE ARCTIC
AIR IS COMPOSED OF TWO STRONG SHORTWAVES THAT ARE FORECAST TO ROTATE
COUNTERCLOCKWISE WITHIN THE BROAD CIRCULATION.

BY DAYBREAK THURSDAY THE MODELS DEPICT THE SHORTWAVE ASSOCIATED WITH
THE WIDESPREAD SNOWFALL FROM MONDAY-WEDNESDAY LIFTING NORTHEASTWARD
INTO MANITOBA/ONTARIO. THUS WILL KEEP THURSDAY DRY. MEANWHILE AT THE
SURFACE...THE ARCTIC HIGH AXIS SHOULD EXTEND FROM NORTHERN ALBERTA
TO EASTERN MONTANA AND THE WESTERN DAKOTAS. AFTER MORNING LOWS FROM
10 TO 15 BELOW IN THE WEST TO 5 TO 10 BELOW IN CENTRAL NORTH
DAKOTA...TEMPERATURES WILL STRUGGLE TO RISE TO ZERO. THE LATEST
THINKING IS THAT HIGH TEMPERATURES THURSDAY WOULD RANGE FROM AROUND
ZERO IN THE JAMES RIVER VALLEY TO NEAR 10 BELOW IN THE NORTHWEST.

FRIDAY AND SATURDAY WILL BE DRY BUT WILL REMAIN BITTERLY COLD AS THE
ARCTIC SURFACE HIGH CONTINUES MOVING SOUTHEAST OUT OF ALBERTA AND
MOVES SLOWLY SOUTHEAST ACROSS THE DAKOTAS. THE COLDEST OF THE AIR
MASS MOVES EAST OF THE AREA SATURDAY NIGHT AND TEMPERATURES WARM
SLIGHTLY SUNDAY BEFORE A REINFORCING SHOT OF ARCTIC AIR ARRIVES
SUNDAY NIGHT. WE COULD SEE A CHANCE OF LIGHT SNOW SATURDAY NIGHT
INTO SUNDAY AS A SHORTWAVE MOVES THROUGH THE LARGE UPPER LEVEL
TROUGH...BUT AT THIS TIME IT APPEARS THAT WAVE AND RESULTING
PRECIPITATION WILL BE MAINLY OVER SOUTH CENTRAL TO SOUTHEASTERN
NORTH DAKOTA.

TEMPERATURES THROUGH THE EXTENDED PERIOD WILL REMAIN WELL BELOW
NORMAL. THE COLDEST TIME PERIOD SHOULD BE THURSDAY NIGHT THROUGH
SATURDAY. THE LOWEST NIGHTTIME MINIMUM TEMPERATURES SHOULD OCCUR
THURSDAY NIGHT AND FRIDAY NIGHT. THE LOWEST DAYTIME TEMPERATURES
SHOULD OCCUR FRIDAY AND SATURDAY...WITH HIGHS FROM ZERO TO 10 BELOW.

TEMPERATURES MODIFY SLIGHTLY ON SUNDAY AHEAD OF THE NEXT ARCTIC
SURGE...BUT HIGHS ACROSS THE NORTH MAY STILL REMAIN BELOW ZERO.
IN GENERAL LOWS WILL RANGE FROM 10 TO 20 BELOW. SNOWFALL IN THE
SHORT TERM PERIOD WILL HAVE A NEGATIVE INFLUENCE ON TEMPERATURES. A
BLANKET OF FRESH SNOW COULD RESULT IN EVEN COLDER TEMPERATURES THAN
CURRENTLY FORECAST.

WE WILL DEFINITELY NEED WIND CHILL HIGHLIGHTS...PERHAPS THROUGH THE
ENTIRE EXTENDED PERIOD FOR SOME AREAS. HOWEVER AT THIS TIME WITH THE
CURRENT SHORT TERM HEADLINES IN EFFECT...WILL HIGHLIGHT THE
DANGEROUS WIND CHILLS IN THE HAZARDOUS WEATHER OUTLOOK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 947 PM CST TUE DEC 3 2013

MAINLY IFR TO LIFR CONDITIONS WILL CONTINUE OVERNIGHT INTO
WEDNESDAY MORNING IN LIGHT TO MODERATE SNOW AND BLOWING SNOW.
CONDITIONS EXPECTED TO GRADUALLY IMPROVE WEDNESDAY AFTERNOON FROM
WEST TO EAST ACROSS THE STATE.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST /5 PM MST/ WEDNESDAY FOR
NDZ018>023-025-031>037-040>048-050-051.

WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR NDZ001>005-
009>013-017.

&&

$$

UPDATE/AVIATION...RP KINNEY
SHORT TERM...TM
LONG TERM...JV