Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 180816
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
216 AM CST THU DEC 18 2014

.UPDATE...
ISSUED AT 215 AM CST THU DEC 18 2014

QUICK UPDATE AS A NARROW BAND OF MODERATE TO HEAVY SNOW PER LATEST
RADAR...AND CONFIRMATION FROM LOCAL LAW ENFORCEMENT ACROSS WEST
CENTRAL NORTH DAKOTA. THE GFS 1.5 PVU 850-700MB AXIS ATOP AN AREA
OF 850MB FRONTOGENESIS IS RESULTING IN A NARROW BAND OF HEAVY
SNOWFALL. TIGHT CIRCULATION CAN BE SEEN ON THE 0.5 DEGREE RADAR
SLICE. THE BAND OF SNOW BEGINS FROM HIGHWAY 8...JUST WEST OF
HALLIDAY WHERE LAW ENFORCEMENT REPORTED VISIBILITY OF AROUND
FIFTEEN 15 FEET WITH ABOUT A HALF INCH OF SNOW. WEBCAMS AT
COLEHARBOR AND WHITE SHIELD CONFIRM BRIEF BUT INTENSE SNOW. HAVE
UPDATED THE GRIDDED FORECAST AND FOLLOWED THIS AXIS THROUGH THE
MORNING AS IT SLIDES NORTH. THE BAND EXTENDS SOUTHEAST INTO
GARRISON...WILTON...REGAN AND WING. A NOWCAST WAS SENT EARLIER
REFLECT CURRENT CONDITIONS. UPDATES TO THE TEXT PRODUCTS
FORTHCOMING.


UPDATE ISSUED AT 1212 AM CST THU DEC 18 2014

LATEST WATER VAPOR IMAGERY LOOP PLACES AN UPPER LOW CIRCULATING JUST
SOUTH OF WILLISTON WITH A SHORTWAVE MOVING INTO THE BASE OF THE
TROUGH...LOCATED ACROSS SOUTHEAST MONTANA. THIS SHORTWAVE IS
FORECAST TO PROPAGATE SLOWLY EAST OVERNIGHT/THURSDAY...BEING LOCATED
BETWEEN DICKINSON AND BISMARCK BY 12Z...AND BETWEEN BISMARCK AND
JAMESTOWN BY 18Z THURSDAY. THE LATEST RAP13 BUFKIT SOUNDINGS FOR
KDIK/KBIS/KJMS INDICATE ENOUGH OMEGA/LIFT IN THE LOW LEVEL SATURATED
LAYER WITH RESPECT TO ICE. AS THE FROST POINT EXCEEDS THE
TEMPERATURE...SNOW PRODUCTION WILL RESULT IN THE SUPERSATURATED
ENVIRONMENT FOR A MENTION OF ISOLATED TO SCATTERED SNOW
SHOWERS/MEASURABLE AMOUNTS OVERNIGHT INTO THURSDAY AFTERNOON AS IT
SLOWLY MOVES EAST. HAVE UPDATED THE GRIDS FOR THIS FEATURE AND WILL
MONITOR AS IT EVOLVES THROUGH THE EARLY MORNING. THINKING IS ONE TO
TWO TENTHS OF AN INCH OF SNOW POSSIBLE ACROSS PORTIONS SOUTHERN
NORTH DAKOTA. SCATTERED FLURRIES STILL A GOOD BET WITH THE ACTUAL
UPPER LOW IN THE NORTHWEST AND NORTH CENTRAL OVERNIGHT AND WILL
CONTINUE WITH THIS IDEA.

UPDATE ISSUED AT 949 PM CST WED DEC 17 2014

MAIN ISSUE LATE THIS EVENING WILL BE LIGHT SNOW/FLURRY CHANCES.
TEMPERATURES WILL BE A HASSLE AGAIN ALONG THE BORDER BETWEEN THE
LOW CLOUDS AND CLEAR SKIES OVER CENTRAL ND...BUT TREND SEEMS
REASONABLE SO NO BIG CHANGES HERE.

LATEST 00 UTC NAM AND 02 UTC RAP SHOW A COUPLE SHORTWAVE IMPULSES
ROTATING AROUND AN UPPER LOW OVER EASTERN MONTANA. THE LEAD WAVE
IS AIDING IN THE DEVELOPMENT OF A SMALL BAND OF SNOW SHOWERS
LIFTING NORTHWARD THROUGH SOUTHWEST INTO CENTRAL NORTH DAKOTA.
GROUND REPORTS ARE INDICATING A BRIEF PERIOD OF SNOW SHOWERS WITH
NO SIGNIFICANT ACCUMULATIONS. WITH THE SMALL BAND LIFTING QUICKLY
NORTH...OPTED TO KEEP THIS AS A CONTINUED MENTION OF FLURRIES AS
GETTING A HUNDREDTH OF AN INCH IS NOT LIKELY.

LATER TONIGHT AND INTO THURSDAY MORNING A STRONGER SHORTWAVE MOVES
WEST ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. ALTHOUGH RAP/NAM
QPF IS CURRENTLY NIL...THE RAP/HRRR ARE SHOWING SOME LIGHT RADAR
REFLECTIVITIES DEVELOPING OVER SOUTHWEST NORTH DAKOTA IN THE 07-12
UTC TIMEFRAME. THINKING AS WE GO THROUGH A FEW MORE ITERATIONS OF
THE RAP/HRRR...THIS MAY CONTINUE TO PROGRESS INTO THE SOUTH
CENTRAL DURING THE MORNING HOURS...AND POSSIBLY INCREASE GIVEN THE
STRENGTH OF THE SHORTWAVE. WITH A MOIST BOUNDARY LAYER AND
INCREASING SEEDER-FEEDER MECHANISM WITH INCREASING MID LEVEL
CLOUDS...HAVE EXTENDED FLURRIES THROUGH THURSDAY MORNING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. THINK MID SHIFT WILL HAVE THE
TIME TO RE-EVALUATE AND ADD A MENTION OF LIGHT SNOW FOR THE
MORNING HOURS IF NEEDED. ACCUMULATIONS WILL REMAIN LIGHT BUT THIS
SECOND WAVE LOOKS STRONG ENOUGH TO GIVE SOME OF US A LITTLE MORE
THAN JUST FLURRIES.

UPDATE ISSUED AT 551 PM CST WED DEC 17 2014

LOW STRATUS REMAINS ACROSS MUCH OF WESTERN AND CENTRAL NORTH
DAKOTA...AND WILL ONCE AGAIN BE A CONCERN FOR OVERNIGHT LOW
TEMPERATURES. DO EXPECT THE STRATUS TO BEGIN TO PROGRESS EASTWARD
LATER THIS EVENING AND OVERNIGHT...COVERING MOST IF NOT ALL OF THE
FORECAST AREA BY THURSDAY MORNING. SHORTWAVE LOCATED OVER EASTERN
MONTANA WILL PROVIDE ENOUGH LIFT FOR SOME LIGHT SNOW SHOWERS
MAINLY OVER THE SOUTHWEST. HOWEVER...WHEREVER WE HAVE THE STRATUS
WE CAN EXPECT A FEW FLURRIES. THIS IS CURRENTLY HANDLED WELL BY
PREVIOUS FORECAST.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED DEC 17 2014

CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE MIDWEST WITH TROUGH
MOVING TOWARDS THE SOUTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES
RIDGE WORKING TOWARDS THE MIDWEST WITH COMPACT LOW LIFTING THROUGH
EASTERN MONTANA. BROAD LOW CLOUD COVER REMAINS OVER WESTERN NORTH
DAKOTA...THOUGH SOME HIGHER CLOUDS ARE ALSO MOVING THROUGH WITH
APPROACHING UPPER LOW.

FOR TONIGHT...CLOUD COVER OVER THE WEST WILL SPREAD TOWARDS THE
EAST THROUGH THE NIGHT. SOME LIGHT SNOW IS POSSIBLE WITH
APPROACHING UPPER LOW...MAINLY OVER THE SOUTHWEST...BUT WITH
LIMITED MOISTURE AVAILABLE ANY ACCUMULATIONS WILL BE QUITE LIGHT.
ELSEWHERE...FLURRIES REMAIN POSSIBLE.

ON THURSDAY...UPPER LOW CONTINUES TO SLOWLY WORK ITS WAY TO THE
EAST WHILE MILDER AIRMASS SLOWLY STARTS TO WORK ITS WAY INTO THE
AREA...BRINGING TEMPERATURES CLOSER TO AVERAGE. MODELS CONTINUE TO
KEEP MOISTURE IN PLACE OVER THE REGION KEEPING CLOUDY SKIES OVER
MOST LOCATIONS...WITH SOME CLEARING DEVELOPING OVER THE FAR WEST
IN THE AFTERNOON.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED DEC 17 2014

QUIET THROUGH SATURDAY...ACTIVE END TO THE WEEKEND AND EARLY
HOLIDAY WEEK.

A WEAK SHORTWAVE TROUGH IS PROGGED TO SWING ACROSS SOUTHERN CANADA
SATURDAY/SUNDAY. THIS COULD SPARK SOME LIGHT SNOW SHOWERS ACROSS
NORTHERN NORTH DAKOTA. HOWEVER...IF ANY PRECIPITATION DOES DEVELOP
ONLY VERY LIGHT AMOUNTS SEEM POSSIBLE WITH THIS WAVE AS IT SHOULD BE
DISCONNECTED FROM THE MAIN PACIFIC MOISTURE FLOW THAT WILL ARRIVE
LATER SUNDAY INTO MONDAY.

SPEAKING OF SUNDAY INTO MONDAY...BROAD NORTHWEST FLOW AND A
LONGWAVE TROUGH IS EXPECTED TO DEVELOP ACROSS THE NORTHERN
PLAINS. THIS WILL LEAD TO A MUCH MORE ACTIVE WEATHER PERIOD. AT
THIS TIME IT APPEARS THE MOST SIGNIFICANT IMPACTS WITH THIS SYSTEM
WILL REMAIN JUST SOUTH AND EAST. HOWEVER...THE LATEST MODELS (12
UTC ECMWF/GFS) VARY GREATLY IN THE EVOLUTION OF THIS WAVE AND
PRECIPITATION PLACEMENT. THEREFORE...CLOSE ATTENTION WILL BE GIVEN
TO FOLLOWING MODEL RUNS AND THE EVOLUTION OF THIS SIGNIFICANT WAVE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1212 AM CST THU DEC 18 2014

IFR STRATUS CONTINUES AT KDIK WITH MVFR STRATUS AT KDIK. LOW STRATUS
IS EXPECTED TO MOVE INTO CENTRAL NORTH DAKOTA (KBIS-KMOT) 07-10 UTC
AND INTO KJMS 13-16 UTC. THE LOW STRATUS IS EXPECTED TO LINGER AT
ALL AERODROMES THROUGH THE FORECAST PERIOD. COULD SEE SOME LIFTING
AT KDIK LATE IN THE PERIOD BUT FOR NOW WILL KEEP THE LOW CLOUDS AT
KDIK THROUGH 06 UTC.

A COUPLE SHORTWAVES ROTATING AROUND AN UPPER LOW...WHICH TRACKS EAST
ACROSS THE FORECAST AREA THROUGH THURSDAY WILL PROVIDE PERIOD OF
LIGHT SNOW. THE FIRST IS EXPECTED TO BRING SOME POSSIBLE LIGHT SNOW
TO KISN AND KMOT LATE TONIGHT. THE SECOND WAVE WILL PROVIDE A CHANCE
OF LIGHT SNOW ACROSS THE SOUTHERN TAF SITES...KDIK AROUND 10-16
UTC...KBIS AROUND 14-20 UTC AND KJMS AROUND 18-24 UTC. DID ADD A
TEMPO AT KDIK AND KBIS FOR SOME LOWER CEILINGS/VSBYS IN SNOW
SHOWERS. WILL HOLD OFF ON LOWER CIGS/VSBYS FOR KJMS AT THIS TIME AS
IT`S PRETTY FAR OUT.


&&

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

$$

UPDATE...KS
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH







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