Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 220938
AFDBIS

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

.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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1240 AM CST SAT NOV 22 2014

LCL IFR VIS WILL BE POSSIBLE THROUGHOUT THE AREA TONIGHT SHOULD
PATCHY FOG DEVELOP. MELTING SNOW ON FRIDAY HAS ADDED LOW LEVEL
MOISTURE...BUT THE SOUTHWESTERLY WINDS MAY MAINTAIN AT 5 TO 10 MPH
AND KEEP THE LOWER ATMOSPHERE MIXED ENOUGH TO PREVENT FOG. WILL
REFRAIN FROM ADDING TO INDIVIDUAL TERMINAL FORECASTS FOR NOW AS
COVERAGE IS EXPECTED TO BE LOW AND CONFIDENCE IS LOW FOR DEVELOPMENT
AND TIMING IS STILL IN QUESTION. AFTER SUNRISE EXPECTING SCT-BKN MID
CLOUDS WITH SOME 5000 FT CU AS LIGHT RAIN MAY DEVELOP IN WESTERN AND
NORTH CENTRAL NORTH DAKOTA AFTER 18Z. AFTER 00Z KEPT A MENTION OF
VCSH WITH A POSSIBLE MIX OF RAIN...FREEZING RAIN...AND SNOW AT
KISN/KDIK THROUGH 06Z.


&&

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

$$

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






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