Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 250358
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
958 PM CST MON NOV 24 2014

.UPDATE...
ISSUED AT 958 PM CST MON NOV 24 2014

THE 00 UTC GFS HAS COME INTO AGREEMENT WITH THE 18 UTC AND 00 UTC
NAM WITH STRONGER MESOSCALE BANDING OF MODERATE TO HEAVY SNOW ASSOCIATED
WITH STEEP MID LEVEL LAPSE RATES AND A MORE POTENT SHORTWAVE
ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA. WILL WAIT FOR THE
REMAINDER OF THE 00 UTC SUITE TO COME IN...HOWEVER...A WINTER
WEATHER ADVISORY FOR SNOWFALL WITH A BAND OF THREE TO FIVE INCHES
FROM THE NORTHWEST ARCHING INTO THE CENTRAL IS INCREASING IN
LIKELIHOOD OF BEING ISSUED AT SOME POINT TONIGHT. WILL ALSO HAVE TO
MONITOR THE WIND POTENTIAL WEST TUESDAY AFTERNOON WITH SIGNIFICANT
ISALLOBARIC FORCING AND 0-2 KM MEAN WINDS OF 45 TO 50 KTS.

UPDATE ISSUED AT 731 PM CST MON NOV 24 2014

PER COORDINATION WITH WFO GRAND FORKS AND ABERDEEN...ADDED PATCHY
LIGHT FREEZING DRIZZLE TO THE SOUTH CENTRAL...THROUGH THE TURTLE
MOUNTAINS AND THE JAMES RIVER VALLEY BETWEEN 06-12 UTC TONIGHT AS
THE STRATUS DECK ACROSS THE NORTHWEST CONTINUES TO PROPAGATE EAST.
THE 18 UTC NAM/GFS BUFR SOUNDINGS SUGGEST THE POTENTIAL FOR THE
LACK OF ICE CRYSTALS IN THE COLUMN WITH SATURATION WARMER THAN -10
C.

UPDATE ISSUED AT 554 PM CST MON NOV 24 2014

THE FOCUS FOR THE SHORT TERM IS THE TUESDAY INTO TUESDAY EVENING
SNOW EVENT. DID INCREASE FORECAST SNOWFALL AMOUNTS FOR THE EVENT
INTO THE TWO TO FOUR INCH RANGE FOR LOCATIONS GENERALLY BOUNDED
ALONG AND EAST OF US HIGHWAY 83 AND ALONG AND SOUTH OF US HIGHWAY
2. THIS IS SUPPORTED BY STEEP MID LEVEL LAPSE RATES EXPECTED
TUESDAY AFTERNOON AND INTO THE EVENING WITH GOOD OMEGA IN THE
DENDRITIC GROWTH ZONE. THESE TOTALS ARE IN LINE WITH THE 15 UTC
SREF SNOWFALL PLUMES...18 UTC GFS AND 12 UTC ECMWF. THE 18 UTC NAM
APPEARS TO BE THE OUTLIER FOR NOW...WITH SNOWFALL ACCUMULATIONS OF
4 TO 6 INCHES OFFERED FOR THE EVENT. WILL SEE IF THIS CONTINUES
WITH ITS UPCOMING 00 UTC RUN. ALSO...SIGNIFICANT DIFFERENCES IN
THE LOW TO MID LEVEL WIND FIELD ARE NOTED BETWEEN THE 18 UTC
GFS/NAM BUFR SOUNDINGS...WITH THE NAM MUCH STRONGER INTO ADVISORY
LEVEL CRITERIA. THIS IS LIKELY AN ARTIFACT OF ITS STRONGER MESOSCALE
FORCING AND PRECIPITATION GENERATION.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 306 PM CST MON NOV 24 2014

FORECAST CHALLENGE TODAY WILL BE SNOW AMOUNTS TUESDAY. TONIGHT A
REGION OF SURFACE HIGH PRESSURE WILL KEEP SKIES CLEAR THE CENTRAL
AND EAST PORTION OF THE FORECAST AREA. MEANWHILE A WEAK RIPPLE IN
THE H5 NORTHWEST FLOW WILL BRING CLOUDS ACROSS A BAROCLINIC
ZONE ACROSS WESTERN NORTH DAKOTA PRODUCING FLURRIES/SLIGHT
CHANCE OF SNOW. SEE LITTLE/NO ACCUMULATION WITH THIS WEAK FEATURE.
ON TUESDAY A MORE SUBSTANTIAL SHORTWAVE WILL MIGRATE ACROSS THE
BAROCLINIC ZONE. THIS WILL SUPPORT THE DEVELOPMENT OF A SURFACE LOW
PRESSURE AREA ACROSS EASTERN MONTANA THAT WILL TRACK SOUTHEAST
THROUGH WESTERN NORTH DAKOTA. THIS WILL PLACE A RELATIVE WARM
SECTOR OVER SOUTHWEST NORTH DAKOTA WITH FORECAST HIGHS THERE IN THE
MID 30S. THIS WILL BE WARM ENOUGH FOR A RAIN SNOW MIX SOUTHWEST
TUESDAY AFTERNOON. ACROSS THE CENTRAL AND NORTH ALL SNOW IS
EXPECTED TUESDAY AND TUESDAY NIGHT. DURING THIS 24 HOUR PERIOD
CURRENT EXPECTATIONS FOR SNOW AMOUNTS ARE 1 TO 3 INCHES ACROSS
NORTHERN AND CENTRAL NORTH DAKOTA...FROM WILLISTON TO GARRISON TO
JAMESTOWN. LESSER AMOUNTS ON EITHER SIDE OF THIS LINE. FOR THIS
EVENT AND FOR THE REMAINDER OF THE WEEK WILL ISSUE A SPECIAL
WEATHER STATEMENT AND KEEP THIS HIGHLIGHTED IN THE HAZARDOUS
WEATHER OUTLOOK.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 306 PM CST MON NOV 24 2014

THE MAIN FORECAST CONCERN IN THE LONG TERM PERIOD WILL BE PERIODIC
CHANCES FOR LIGHT SNOW AND COLD TEMPERATURES.

A QUICK MOVING H5 WAVE WILL CONTINUE TO PUSH ACROSS PARTS OF CENTRAL
AND EASTERN NORTH DAKOTA TUESDAY EVENING.  LIGHT SNOW WILL CONTINUE
TUESDAY EVENING...ESPECIALLY TOWARDS THE JAMES RIVER VALLEY.

ONCE THIS WAVE EXITS...ATTENTION SHIFTS BACK TO THE WEST CLOSER TO
A QUASI-STATIONARY FRONTAL BOUNDARY. ISENTROPIC LIFT INCREASES
OVER WESTERN NORTH DAKOTA WEDNESDAY....THEN SHIFTS ACROSS THE
STATE WEDNESDAY NIGHT AND THURSDAY. THIS WILL BRING MORE LIGHT
SNOW CHANCES...WITH 1 TO 2 INCHES OF SNOW POSSIBLE IN THE WEST /
SOUTHWEST WEDNESDAY INTO WEDNESDAY NIGHT. THE BETTER CHANCES FOR
ACCUMULATIONS THEN SHIFT NORTH AND EAST FOR THANKSGIVING DAY INTO
EARLY FRIDAY. THERE ARE A COUPLE MODELS SOLUTIONS THAT SUGGEST
THERE COULD BE A LIGHT WINTRY MIX ON THURSDAY AS WARMER AIR ALOFT
MOVES BACK INTO NORTH DAKOTA. CONFIDENCE IN THIS IS NOT HIGH...SO
WILL NOT INTRODUCE YET.

TEMPERATURES WILL BE COLD TO START THE LONG TERM PERIOD...AND WIND
CHILLS COULD APPROACH 25 BELOW ZERO WEDNESDAY NIGHT INTO THURSDAY
MORNING TOWARDS THE TURTLE MOUNTAINS.  WARMER AIR ARRIVES BY
FRIDAY...BUT ANOTHER ROUND OF ARCTIC AIR LOOMS FOR THE WEEKEND.
THIS COULD AGAIN PUSH WIND CHILLS TO NEAR 25 BELOW ZERO IN NORTHERN
PARTS OF THE STATE SATURDAY NIGHT INTO SUNDAY MORNING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 957 PM CST MON NOV 24 2014

MVFR STRATUS WITH OCCASIONAL LIGHT SNOW WILL OVERSPREAD WESTERN
AND CENTRAL NORTH DAKOTA THIS EVENING...TRENDING INTO IFR CEILINGS
AND VISIBILITIES THROUGH TUESDAY IN LIGHT TO MODERATE SNOW. PATCHY
LIGHT FREEZING DRIZZLE MAY BE POSSIBLE AT KBIS AND KJMS LATE
TONIGHT.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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






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