Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 221243
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
643 AM CST SAT NOV 22 2014

.UPDATE...
ISSUED AT 642 AM CST SAT NOV 22 2014

LOW PRESSURE DEVELOPING IN THE LEE OF THE CANADIAN ROCKIES WILL
MOVE INTO SOUTHERN SASKATCHEWAN BY EARLY THIS EVENING. WARM
ADVECTION PRECIPITATION IS EXPECTED TO REMAIN MAINLY IN CANADA BUT
COULD SKIRT THE FAR NORTHERN BORDER THIS AFTERNOON. SHORTWAVE
ENERGY CURRENTLY MOVING INTO THE NORTHERN ROCKIES WILL BRING A
CHANCE OF SHOWERS TO WESTERN NORTH DAKOTA BY THIS AFTERNOON.
CURRENT THINKING IS THAT ANY DAYTIME PRECIPITATION WILL BE RAIN.
CURRENTLY...HIGH LEVEL CLOUDS ARE MOVING INTO WESTERN NORTH DAKOTA
WITH MVFR STRATUS OVER SOUTHERN SASKATCHEWAN AND MANITOBA AND
DIPPING DOWN INTO FAR NORTHEAST NORTH DAKOTA. OTHERWISE MAINLY
CLEAR TO START THE MORNING. LOWERED SKY COVER ACROSS CENTRAL NORTH
DAKOTA THIS MORNING. OTHERWISE NO SIGNIFICANT UPDATES TO THE
CURRENT FORECAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CST SAT NOV 22 2014

HIGHLIGHTS IN THE SHORT TERM INCLUDE A LOW PRESSURE SYSTEM THAT WILL
BRING A WARM FRONT ACROSS THE REGION TODAY...AND A COLD FRONT
TONIGHT. A WARM DAY TODAY WITH A CHANCE OF RAIN SHOWERS...FOLLOWED
BY COLD AIR MOVING INTO THE FORECAST AREA TONIGHT...WITH THE SYSTEM
BRINGING A MIX OF PRECIPITATION TYPES TO WESTERN AND CENTRAL NORTH
DAKOTA.

CURRENTLY...A STRONG UPPER LEVEL SHORTWAVE WAS OVER THE PACIFIC
NORTHWEST...WITH MAINLY ZONAL WEST-TO-EAST FLOW OVER NORTH DAKOTA. A
LEE-SIDE SURFACE LOW CONTINUED TO DEVELOP OVER BRITISH
COLUMBIA/ALBERTA THIS MORNING IN RESPONSE TO THE UPPER LEVEL
SHORTWAVE. A SURFACE LEE-SIDE TROUGH EXTENDED FROM THE SURFACE LOW
SOUTHWARD ALONG THE FRONT RANGE. THIS WAS KEEPING THE SURFACE WINDS
OVER NORTH DAKOTA IN A LIGHT SOUTHWESTERLY REGIME...WITH
TEMPERATURES IN THE MID 20S TO LOWER 30S ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.

THE UPPER LEVEL SHORTWAVE IS PROGGED TO EMERGE INTO THE FRONT RANGE
OF MONTANA AND SOUTHERN SASKATCHEWAN THIS MORNING...AND MOVE EAST
INTO MANITOBA AND THE DAKOTAS TONIGHT. MEANWHILE THE SURFACE LOW IS
PROGGED TO MOVE EAST TO SOUTHERN SASKATCHEWAN THIS AFTERNOON...AND
REACH THE MANITOBA/NORTH DAKOTA/MINNESOTA BORDER BY SUNRISE ON
SUNDAY MORNING.

AS THE SURFACE LOW MOVES EAST...THE ASSOCIATED WARM FRONT WILL MOVE
EAST ACROSS THE DAKOTAS TODAY. HIGHS SHOULD BE MAINLY IN THE 40S
OVER THE STATE...NEARING 50 IN THE SOUTHWEST. THE UPPER LEVEL
SHORTWAVE ENERGY COMBINED WITH THE SURFACE CONVERGENCE/LIFTING ALONG
THE WARM FRONT WILL BRING A CHANCE OF RAIN SHOWERS TO WESTERN NORTH
DAKOTA THIS AFTERNOON.

TONIGHT THE COLD FRONT ASSOCIATED WITH THE SYSTEM MOVES INTO WESTERN
NORTH DAKOTA DURING THE EVENING...REACHING THE JAMES RIVER VALLEY
BEFORE SUNRISE. A COMPLICATED SCENARIO OF PRECIPITATION TYPES WITH
THE WARM AIR ALOFT AHEAD OF THE COLD FRONT TO PRODUCE A PERIOD OF
SLEET/FREEZING RAIN AHEAD OF THE COLD AIR...BEFORE CHANGING OVER TO
SNOW FROM WEST TO EAST WITH TIME.

OVER WESTERN NORTH DAKOTA...EXPECTING RAIN EARLY IN THE EVENING
CHANGING RATHER QUICKLY TO SNOW - WITH ONLY A BRIEF PERIOD OF SLEET
OR FREEZING RAIN.

OVER CENTRAL NORTH DAKOTA...CHANCES OF RAIN IN THE EVENING COULD BE
MIXED WITH FREEZING RAIN - DEPENDING ON HOW QUICKLY SURFACE
TEMPERATURES DIP BELOW FREEZING. AS THE COLD FRONT MAKES ITS WAY
EAST ACROSS CENTRAL NORTH DAKOTA...ANY PRECIPITATION THAT FALLS
SHOULD CHANGE TO ALL SNOW. IN THE JAMES VALLEY...THIS MAY NOT OCCUR
UNTIL AROUND SUNRISE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 338 AM CST SAT NOV 22 2014

THE MAIN FORECAST HIGHLIGHT IN THE EXTENDED PERIOD CONTINUES TO BE
THE POTENTIAL FOR HAZARDOUS WINTER WEATHER IN SNOW AND BLOWING SNOW
SUNDAY THROUGH EARLY MONDAY.

WE BEGIN THE PERIOD SUNDAY MORNING WITH A SURFACE LOW PROGGED NEAR
RUGBY ON THE 22 NOV 00 UTC GFS. THE GEM/ECMWF ARE A LITTLE FARTHER
NORTH WITH THE LOW IN FAR SOUTHERN MANITOBA. BY THIS TIME A MID
LEVEL SHORTWAVE IS EXPECTED TO BE MOVING ACROSS THE DAKOTAS WITH ITS
ASSOCIATED PRECIPITATION EXITING EASTERN PORTIONS OF CENTRAL NORTH
DAKOTA...WITH WRAP AROUND MOISTURE AND STRONG WINDS PUSHING INTO
WESTERN NORTH DAKOTA. THERE IS STILL ENOUGH WARM AIR ALOFT OVER THE
JAMES RIVER VALLEY THAT IF THERE IS SOME LINGERING PRECIPITATION
HERE AFTER 12 UTC SUNDAY...IT COULD FALL AS FREEZING RAIN. THIS WILL
QUICKLY END AS STRONG COLD ADVECTION DROPS TEMPERATURES ALOFT. THE
MAIN HAZARD ON MONDAY WILL BE COMBINATION OF STRONG NORTHWEST WINDS
WITH GUSTS OF 40 TO 50 MPH...COMBINED WITH SNOW SHOWERS ASSOCIATED
WITH THE WRAP AROUND MOISTURE ON THE BACK SIDE OF THE MID LEVEL LOW
AS IT TRACKS SOUTHEAST ACROSS THE FORECAST AREA.

THE STRONG WINDS AND SNOW SHOWERS COULD STILL BE AN ISSUE OVER
EASTERN PORTIONS OF CENTRAL NORTH DAKOTA INTO MONDAY MORNING. WILL
CONTINUE TO MONITOR FOR POSSIBLE HIGHLIGHTS FOR THE LATE SAT
NIGHT-SUNDAY NIGHT PERIOD. FOR NOW WE WILL ISSUE AN SPS HIGHLIGHTING
THE MIXED PRECIPITATION SATURDAY NIGHT AND THE SNOW/BLOWING SNOW ON
SUNDAY AND SUNDAY NIGHT.

AFTERWARDS...TUESDAY-FRIDAY...ANOTHER CLIPPER MOVES ACROSS THE
FORECAST AREA TUESDAY-TUESDAY EVENING WHICH WOULD BRING ANOTHER
SWATH OF LIGHT SNOW ACROSS THE AREA. THIS IS FOLLOWED BY ANOTHER
SURGE OF COLD AIR ON WEDNESDAY. SIGNIFICANT DIFFERENCES BETWEEN THE
GFS/GEM AND THE ECMWF WITH THE INTERACTION OF THE COLD SURGE AND A
BUILDING UPPER RIDGE TO THE WEST. THE GFS/GEM ARE FARTHER WEST WITH
THE COLD HIGH DROPPING SOUTH AND THUS THE BUILDING RIDGE IS
FLATTER...WHICH RESULTS IN A BAROCLINIC ZONE OF PRECIPITATION
EXTENDING ACROSS MONTANA AND INTO WESTERN AND SOUTH CENTRAL NORTH
DAKOTA ON WEDNESDAY. THIS COULD PRODUCE SOME ACCUMULATING SNOW AND
POSSIBLY SOME MIXED PRECIPITATION OVER THE FAR SOUTHWEST. THE ECMWF
KEEPS ANY PRECIPITATION CONFINED TO THE FAR SOUTHWEST. FOR NOW A
MODEL BLEND BRINGS CHANCE POPS TO THE SOUTHWEST...WITH SLIGHT CHANCE
POPS WEST OF A LINE FORM ROUGHLY WILLISTON TO BISMARCK.

IT STILL LOOKS RATHER COLD BUT MAINLY DRY ON THANKSGIVING DAY. BUT
THE WEST COULD RISE INTO THE 20S. BEYOND THURSDAY THE ECMWF
INDICATES AN ACTIVE NORTHWEST FLOW PATTERN WHILE THE GFS CONTINUES
TO GO BACK AND FORTH BETWEEN A COLD NORTHWEST FLOW AND A MORE ACTIVE
QUASI-ZONAL FLOW. THUS WILL CONTINUE TO USE A MODEL BLEND WHICH
GIVES MAINLY 20S FOR HIGHS AND SINGLE DIGITS TO LOWER TEENS FOR LOWS
INTO THE BEGINNING OF THE HOLIDAY WEEKEND...WITH NO SIGNIFICANT
STORM SYSTEMS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 642 AM CST SAT NOV 22 2014

EXPECTING SCT-BKN MID CLOUDS TO MOVE INTO WESTERN NORTH DAKOTA AND
SPREAD EAST. SOME 5000 FT CU TO DEVELOP WITH A CHANCE OF LIGHT RAIN
SHOWERS AT KISN/KDIK/KMOT AFTER 18Z. AFTER 00Z KEPT A MENTION OF
VCSH WITH A POSSIBLE MIX OF RAIN...FREEZING RAIN...AND SNOW AT
KISN/KDIK THROUGH 06Z. AFTER 06Z A SLIGHT CHANCE OF LIGHT SNOW AT
KISN/KDIK. ONLY A SLIGHT CHANCE OF A MIX OF LIGHT RAIN OR FREEZING
RAIN POSSIBLE AT KMOT/KBIS/KJMS AND DID NOT MENTION IN THIS 12Z
ISSUANCE OF THE TAFS. STRONG NORTHWEST WINDS AND BLOWING SNOW
EXPECTED AFTER 12Z DEVELOPING FROM WEST TO EAST ON SUNDAY.

&&

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

$$

UPDATE...TWH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...TWH





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