000
FXUS63 KBIS 051240
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
640 AM CST THU DEC 5 2013

.UPDATE...
ISSUED AT 640 AM CST THU DEC 5 2013

LOW PRESSURE OVER THE NORTHERN GREAT LAKES AND ARCTIC HIGH
PRESSURE DROPPING SOUTH FROM CANADA INTO MONTANA AND THE DAKOTAS
IS RESULTING IN MODERATE NORTHWEST WINDS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA THIS MORNING. SURFACE TEMPERATURES FROM ZERO
TO 10 BELOW WITH WINDS OF 15 TO 25 MPH HAVE RESULTED IN WIND
CHILLS MAINLY FROM 25 TO 35 BELOW ZERO THIS MORNING. NO CHANGES TO
CURRENT WIND CHILL ADVISORY. SOME MVFR TO IFR STRATUS IS STREAMING
SOUTH FROM CANADA AND COULD CONTAIN A FEW FLURRIES. CURRENT
FORECAST HAS A GOOD HANDLE ON THIS WITH LIGHT SNOW NORTH AND
PATCHY BLOWING SNOW THROUGH THE MORNING ACROSS THE ENTIRE AREA. NO
SIGNIFICANT CHANGES TO THE MORNING UPDATE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 302 AM CST THU DEC 5 2013

BLOWING SNOW THIS MORNING CENTRAL AND DANGEROUS WIND CHILLS AREA
WIDE WILL HIGHLIGHT THE SHORT TERM FORECAST.

BASED ON WEBCAMS AND SURFACE OBSERVATIONS AS OF 09
UTC...BLOWING SNOW IS NOT CAUSING SIGNIFICANT VISIBILITY ISSUES
THIS MORNING. HOWEVER...MAINTAINED THE MENTION OF PATCHY TO AREAS
OF BLOWING SNOW INTO THE EARLY AFTERNOON AS STRONG NORTHWEST
WINDS TO 30 KTS ON THE BACKSIDE OF THE DEPARTING LOW WILL
CONTINUE TO LOFT THE POWDERY SNOW. OVERALL WINDS DO SLOWLY WEAKEN
THROUGH THE DAY AS THE PRESSURE GRADIENT WEAKENS AS THE SURFACE
RIDGE AXIS BECOMES LOCATED FROM NORTH CENTRAL MONTANA THROUGH
SOUTHWEST NORTH DAKOTA BY 00 UTC.

IN REGARDS TO TEMPERATURES FOR TODAY...GIVEN THE FRESH SNOW
COVER...CONTINUED LOW LEVEL COLD AIR ADVECTION AND A SUB-ZERO
START TO BEGIN WITH...DID FAVOR THE COOLER EDGE OF GUIDANCE WITH
SUB-ZERO HIGHS FOR TODAY...NAMELY THE 00 UTC ECMWF/GEM. FOR
TONIGHT...AS THE SURFACE RIDGE CONTINUES TO BUILD ACROSS WESTERN
AND CENTRAL NORTH DAKOTA...A FRIGID NIGHT IS IN STORE FOR THE AREA
WITH MUCH WEAKER WINDS COMPARED TO EARLY THIS MORNING. THAT
SAID...WINDS WILL NOT BE CALM EITHER...WITH NORTHWEST WINDS OF
AROUND 10 KTS EMANATING FROM THE HIGH. HOWEVER...WITH THE WEAKER
WINDS...SNOW AND COLD EVENING TEMPERATURES...UPSTREAM OBSERVATIONS
IN CANADA SUPPORT OVERNIGHT LOWS OF -20 F ACROSS THE WEST...TO -10
F TO -15 F CENTRAL. AGAIN...THIS IS WELL BELOW THE 00 UTC
CONSENSUS...FAVORING THE OBSERVED TRENDS ACROSS CANADA THIS
MORNING. THERE IS SOME UNCERTAINTY ON IMPACTS OF LOW...THIN
STRATUS ON TEMPERATURES WHICH IS HARD TO RESOLVE IN BOTH THE
SATELLITE AND THE MODELS. NEEDLESS TO SAY...WIND CHILL
TEMPERATURES STAY LESS THAN -25 F FOR MOST AREAS EVEN DURING THE
DAY TODAY...WITH WIND CHILLS APPROACHING -40 F TONIGHT. WILL
CONTINUE THE WIND CHILL ADVISORY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 302 AM CST THU DEC 5 2013

MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT IN THE LONG TERM
PERIOD. ESPECIALLY THROUGH EARLY NEXT WEEK. ARCTIC AIR WILL REMAIN
OVER THE NORTHERN PLAINS DURING THIS PERIOD WITH A LARGE UPPER LEVEL
TROUGH COVERING MUCH OF THE WESTERN AND CENTRAL U.S. UTILIZED MAINLY
PERSISTENCE FOR TEMPERATURES THROUGH EARLY NEXT WEEK AS BLENDS SEEM
TOO WARM. ESPECIALLY CONSIDERING OUR RECENT WIDESPREAD SNOWFALL
ACROSS WESTERN AND CENTRAL NORTH DAKOTA.

FRIDAY AND SATURDAY WILL BE VERY COLD WITH HIGHS NEAR ZERO FAR SOUTH
TO 10 BELOW NORTH. LOWS FRIDAY NIGHT ARE EXPECTED TO BE 15 TO 25
BELOW ACROSS THE ENTIRE AREA. A SLIGHT MODERATION SATURDAY NIGHT AND
SUNDAY AS THE INITIAL UPPER TROUGH EXITS TO THE EAST BEFORE ANOTHER
REINFORCING SHOT OF ARCTIC AIR SUNDAY NIGHT. EVEN WITH THE SLIGHT
MODERATION HIGHS ON SUNDAY ARE ONLY EXPECTED TO REMAIN IN THE SINGLE
DIGITS ABOVE OR BELOW ZERO. CURRENT WIND CHILL HEADLINES RUN THROUGH
MIDDAY SATURDAY. WILL PROBABLY NEED ADDITIONAL HEADLINES GOING
FORWARD...BUT THIS CAN BE RE-EVALUATED AS WE GET CLOSER TO THE
WEEKEND.

UPPER LEVEL RIDGING OFF THE WEST COAST PUSHES INLAND MONDAY...THUS
OUR ARCTIC SURGE SUNDAY NIGHT WILL TRANSLATE QUICKLY EAST MONDAY.
MONDAY THROUGH WEDNESDAY WILL BRING PERIODIC PACIFIC AND ARCTIC AIR
ACROSS THE LOCAL AREA AS THE RIDGE/TROUGH NORTHWEST FLOW PATTERN
UNDULATES BACK AND FORTH WITH EACH SUCCESSIVE WAVE. THERE ARE SOME
MINOR TIMING DIFFERENCES...BUT GFS/ECMWF INDICATE A CLIPPER MOVING
ACROSS THE AREA MONDAY NIGHT...BRINGING A CHANCE OF LIGHT SNOW AND
GUSTY WINDS. BEYOND TUESDAY...MODELS ARE INDICATING AT LEAST A
TEMPORARY BREAK IN THE PATTERN AS A MORE WESTERLY FLOW BECOMES
ESTABLISHED FROM THE PACIFIC INTO THE NORTHERN PLAINS. HOWEVER...
THE COLD SHOULD REMAIN THROUGH WEDNESDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM CST THU DEC 5 2013

SCATTERED MVFR STRATUS...WITH POCKETS OF IFR WILL CONTINUE AT LEAST
THROUGH THIS MORNING. THERE IS SOME UNCERTAINTY AS TO HOW THE
STRATUS WILL EVOLVE THROUGH THE AFTERNOON AS THIN ARCTIC STRATUS IS
HARD TO RESOLVE IN BOTH THE SATELLITE AND THE MODELS. IFR CONDITIONS
IN BLOWING SNOW AND LIGHT FALLING SNOW ARE POSSIBLE AT KJMS AND KMOT
THROUGH 15-16 UTC THIS MORNING.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ SATURDAY FOR
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.

&&

$$

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