000
FXUS63 KBIS 201229
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
629 AM CST FRI DEC 20 2013

.UPDATE...
ISSUED AT 629 AM CST FRI DEC 20 2013

WIND CHILLS ARE RUNNING ABOUT 25 TO 30 BELOW ZERO OVER MOST OF
WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. AS A RESULT...WILL
KEEP THE CURRENT TEMPORAL AND SPATIAL RESOLUTION OF THE WIND CHILL
ADVISORY IN EFFECT.

HIGH PRESSURE SHIFTING EAST OF THE REGION WILL MAINTAIN DRY AND COLD
CONDITIONS ACROSS THE STATE TODAY. AFTERNOON HIGHS WILL STRUGGLE TO
GET INTO THE SINGLE DIGITS ABOVE ZERO EAST OF HIGHWAY 83.

THE CURRENT FORECAST IS ON TRACK WITH NO MAJOR UPDATES REQUIRED.
FRESHENED UP PRODUCTS HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST FRI DEC 20 2013

TEMPERATURES AND WIND CHILL VALUES ACROSS THE FORECAST AREA ARE THE
MAIN CONCERNS IN THE SHORT TERM.

A WIND CHILL ADVISORY REMAINS IN EFFECT THROUGH LATE MORNING.
TEMPERATURES WERE MAINLY IN THE 10 TO 20 BELOW ZERO RANGE EARLY THIS
MORNING...WITH WIND CHILLS OF 25 TO 40 BELOW EXPECTED TO PERSIST
THROUGH LATE MORNING.

A SURFACE ARCTIC HIGH PRESSURE AXIS THAT EXTENDED FROM EASTERN
MONTANA ACROSS SOUTHERN NORTH DAKOTA INTO NORTHERN MINNESOTA IS
FORECAST TO MOVE SOUTHEASTWARD TODAY. MEANWHILE UPPER LEVEL CYCLONIC
FLOW REMAINS ACROSS THE REGION...AND AN UPPER LEVEL VORT ENERGY
IMPULSE WILL MOVE EASTWARD THROUGH THE FLOW THIS
AFTERNOON...SPREADING SOME MID-LEVEL CLOUDINESS INTO WESTERN NORTH
DAKOTA THIS AFTERNOON AND REACHING CENTRAL NORTH DAKOTA THIS
EVENING. THE CLOUD COVER WILL ACCOMPANY WARM ADVECTION MOVING IN AS
THE SURFACE HIGH EXITS THE REGION...AND TEMPERATURES IN THE
SOUTHWEST ARE EXPECTED TO RISE TO AROUND 10 TO 15 ABOVE THIS
AFTERNOON. DO NOT EXPECT TEMPERATURES IN THE JAMES RIVER VALLEY TO
RECOVER MUCH ABOVE 5F.

ANOTHER UPPER LEVEL VORT ENERGY IMPULSE IS FORECAST TO MOVE EAST
ACROSS SOUTHERN MONTANA TONIGHT...APPROACHING WESTERN NORTH DAKOTA
LATE TONIGHT. KEPT A MENTION OF SLIGHT CHANCE OF LIGHT SNOW OVER
WESTERN NORTH DAKOTA AROUND MIDNIGHT AND SPREADING TO NORTH CENTRAL
NORTH DAKOTA LATE. LOWS TONIGHT ARE EXPECTED TO RANGE FROM AROUND
ZERO IN THE SOUTHWEST TO NEAR 10 BELOW IN THE TURTLE MOUNTAINS.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 323 AM CST FRI DEC 20 2013

THE MEDIUM RANGE MODELS ARE NOW A LITTLE STRONGER WITH A
SHORTWAVE/ALBERTA CLIPPER GENERATING SNOW CHANCES OVER WESTERN AND
CENTRAL NORTH DAKOTA SATURDAY. AS LONG AS THIS FEATURE REMAINS AN
OPEN WAVE...SNOWFALL AMOUNTS BY SATURDAY NIGHT SHOULD BE AROUND AN
INCH NORTH OF HIGHWAY 2...AND LESS THAN AN INCH SOUTH OF HIGHWAY
2.

DRY ARCTIC AIR WILL THEN FILTER IN BEHIND THE WAVE SUNDAY/SUNDAY
NIGHT GENERATING THE COLDEST TEMPS OF THE PERIOD. WIDESPREAD WIND
CHILL VALUES AROUND 30 BELOW ZERO (WITH POCKETS OF 35 BELOW ZERO)
ARE FORECAST FOR SUNDAY NIGHT. DRY CONDITIONS CONTINUE AND
TEMPERATURES BEGIN TO MODERATE WEST MONDAY AS UPPER LEVEL RIDGING
DEVELOPS OVER THE NORTHERN ROCKIES.

THE MEDIUM RANGE MODEL SOLUTIONS BEGIN TO DIVERGE WITH RESPECT TO
THE UPPER PATTERN TUESDAY AND BEYOND. THE LATEST ECMWF IS MORE
PROGRESSIVE AND FARTHER SOUTH WITH THE TRACK OF THE NEXT ALBERTA
CLIPPER FORECAST TO AFFECT THE REGION. THE GFS IS RELATIVELY
SLOWER AND FARTHER NORTH WITH THIS FEATURE. GIVEN THE MODEL TO
MODEL AND RUN TO RUN INCONSISTENCIES...OPTED TO BROAD BRUSH SLIGHT
CHANCE POPS AREAWIDE FOR THE TUE-WED PERIOD. BOTH THE LATEST
ECMWF/GFS DEEPEN THE CLIPPER INTO A LOW OVER ONTARIO THURSDAY.
THIS WOULD GENERATE YET ANOTHER SURGE OF ARCTIC AIR AND WELL BELOW
NORMAL TEMPERATURES INTO NORTH DAKOTA BY THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 629 AM CST FRI DEC 20 2013

LARGE ARCTIC HIGH PRESSURE AXIS EXTENDED FROM THE DAKOTAS TO
NORTHERN MINNESOTA. THIS HIGH IS FORECAST TO MOVE SOUTHEAST AND
WILL BRING VFR CONDITIONS BUT VERY COLD AIR TO THE REGION TODAY.
SOUTH TO SOUTHWEST WINDS TODAY AS THE ARCTIC HIGH EXITS TO THE
SOUTHEAST. ANOTHER COLD FRONT WILL DROP SOUTH INTO NORTHERN NORTH
DAKOTA AROUND 03Z AND MOVE SOUTH ACROSS THE STATE TONIGHT. MVFR
CIGS ARE POSSIBLE LATE TONIGHT BEHIND THE COLD FRONT.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.

&&

$$

UPDATE...TM
SHORT TERM...JV
LONG TERM...TM
AVIATION...JV