Area Forecast Discussion
Issued by NWS Bismarck, ND

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KBIS 311237
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
637 AM CST SAT JAN 31 2015

.UPDATE...
ISSUED AT 637 AM CST SAT JAN 31 2015

NO MAJOR CHANGES TO THE GOING FORECAST. LIGHT SNOW IS DEVELOPING
ACROSS THE NORTHERN TIER COUNTIES THIS MORNING AND WILL SPREAD
SOUTH AND EAST THROUGH THE DAY. DID EXTEND THE MENTION OF FOG
THROUGH 15 UTC ACROSS THE SOUTHWEST AND FAR SOUTH CENTRAL. UPDATED
TEXT WILL BE OUT SHORTLY

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST SAT JAN 31 2015

THE MAIN FOCUS FOR THE SHORT TERM IS ACCUMULATING SNOW TODAY/TONIGHT.

A SHORTWAVE TROUGH CURRENTLY OVER SOUTHERN ALBERTA AND AN INVERTED
SURFACE TROUGH...CURRENTLY CENTERED ACROSS EASTERN MONTANA...WILL
SLOWLY PROPAGATE SOUTHEAST THROUGH THE MORNING HOURS. AS IT DOES
WIDESPREAD SNOW ACROSS SOUTHERN CANADA IS EXPECTED TO CONTINUE TO
DEVELOP AND ENTER NORTHWESTERN NORTH DAKOTA. A DEFORMATION ZONE IS
EXPECTED TO SET UP ACROSS WESTERN NORTH DAKOTA LATER THIS MORNING
AS A SHORTWAVE TROUGH OVER THE FOUR CORNERS INTERACTS WITH THE
ALBERTA SHORTWAVE. 00 UTC MODELS ARE IN GOOD AGREEMENT ON TIMING
AND LOCATION OF THE SNOW. BY 6AM A LIGHT SNOW BAND SHOULD BEGIN
OVERSPREADING NORTHWESTERN NORTH DAKOTA. THIS BAND IS EXPECTED TO
SLIDE SLOWLY SOUTH THROUGH THE DAY. THE ECMWF/NAM/SREF/GFS ALL
HAVE THE HEAVIEST QPF AMOUNTS ACROSS WEST CENTRAL NORTH DAKOTA
DURING THE AFTERNOON HOURS. FOR THE FORECAST WENT WITH A BLEND OF
THE OPERATIONAL MODELS WHICH ENDS UP PRODUCING WIDESPREAD 2 TO 3
INCHES OF SNOW ACROSS WESTERN AND CENTRAL NORTH DAKOTA...WITH
HEAVIEST AMOUNTS WEST OF HIGHWAY 83.

TEMPERATURES WILL CONTINUE TO GRADUALLY FALL THROUGH THE DAY WITH
CLOUDY SKIES LIMITING SOLAR INSULATION AND COLD AIR ADVECTION
CONTINUES IN FULL FORCE. TEMPERATURES WILL LIKELY FALL BELOW ZERO
ACROSS THE JAMES VALLEY TONIGHT. WIND CHILL READINGS WILL NEAR 20
BELOW BY THE EARLY MORNING HOURS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM CST SAT JAN 31 2015

MAIN FORECAST HIGHLIGHTS ARE COLD AND UNSETTLED WEATHER THROUGH AT
LEAST MID WEEK WITH A NUMBER OF LIGHT SNOW EVENTS. THEN POSSIBLY A
RETURN TO MORE MILD CONDITIONS AT THE END OF THE EXTENDED PERIOD.

DETERMINISTIC MODELS ARE IN QUITE GOOD AGREEMENT THROUGH MOST OF THE
EXTENDED PERIOD AND USED A MODEL BLEND FOR FORECAST DETAILS.

WE BEGIN THE PERIOD SUNDAY WITH A 1040 MB SURFACE HIGH DROPPING
FROM SOUTHERN CANADA INTO CENTRAL NORTH DAKOTA BY 18 UTC SUNDAY.
LIGHT SNOWS FROM THE EXITING SHORT TERM SYSTEM SHOULD BE ALL BUT OUT
OF THE SOUTHERN CWA BY 18 UTC...BUT DID INCLUDE A SLIGHT CHANCE OF
LIGHT SNOW WITH OVER THE FAR SOUTH CENTRAL AS REMNANTS MOVE OUT OF
THE FORECAST AREA SUNDAY MORNING. OTHERWISE DRY BUT COLD SUNDAY.
WIND CHILL HIGHLIGHTS MAY BE NEEDED SUNDAY MORNING IF CURRENT TRENDS
HOLD...OVER THE TURTLE MOUNTAINS INTO THE JAMES RIVER VALLEY.

AS THE SURFACE HIGH SLIDES SOUTHEAST SUNDAY NIGHT WARM ADVECTION
RETURNS TO WESTERN NORTH DAKOTA. BY MONDAY MORNING...UPPER LEVEL
FORCING WITH A 120KT JET INDUCES A SURFACE LOW PRESSURE CENTER OVER
SOUTHEAST MONTANA THAT TRACKS SOUTHEAST ACROSS INTO CENTRAL SOUTH
DAKOTA. THE GFS IS THE WEAKEST AND FARTHEST SOUTH WITH THE SURFACE
LOW AND BRINGS VERY LIGHT SNOW AMOUNTS INTO THE FAR SOUTHWEST. ALL
OTHER DETERMINISTIC MODELS TRACK THE SURFACE LOW IN A FAVORED
POSITION TO BRING LIGHT SNOWS TO WESTERN AND SOUTH CENTRAL NORTH
DAKOTA. AMOUNTS HERE ARE DEFINITELY SUB-ADVISORY CRITERIA AND AS A
FIRST GUESS HAVE GONE WITH HALF INCH TO ONE INCH AMOUNTS ALONG AND
SOUTH OF LAKE SAKAKAWEA AND THE MISSOURI RIVER...WITH LITTLE OR NO
ACCUMULATIONS NORTH AND EAST OF HERE. TAKING THE GFS OUT OF THE
BLEND WOULD YIELD HIGHER AMOUNTS...MAYBE 1-2 INCHES IN THIS SAME
GENERAL AREA...SO WILL HAVE TO MONITOR...BUT STILL SUB-ADVISORY
SNOWS.

ANOTHER IMPULSE QUICKLY RACES INTO THE AREA ALREADY BY LATE MONDAY
NIGHT. THIS TIME THERE IS A TIGHTER BAROCLINIC ZONE THAT IMPULSES
WILL INTERACT WITH OVER THE SAME GENERAL AREA OF WESTERN INTO SOUTH
CENTRAL NORTH DAKOTA. THERE ARE SOME MODEL DIFFERENCES IN THE
PLACEMENT OF THE SURFACE AND UPPER LEVEL FEATURES BUT MODELS ARE
CURRENTLY IN GOOD AGREEMENT IN BRINGING ANOTHER SWATH OF LIGHT SNOWS
OVER WESTERN AND SOUTH CENTRAL NORTH DAKOTA...WITH THE TURTLE
MOUNTAINS AREA ONCE AGAIN SEEING THE THE SMALLEST CHANCES OF
ACCUMULATING SNOWS. IN GENERAL...WE ARE TALKING SUB-ADVISORY
CRITERIA SNOWS OF 1 TO 3 INCHES LATE MONDAY NIGHT THROUGH TUESDAY.
THE GFS IS A LITTLE MORE IMPRESSIVE WITH THE SURFACE LOW AND HINTS
AT SOME INDIRECT JET CIRCULATION BETWEEN THE TWO STRONG JETLETS OVER
THE NORTHERN PLAINS. THUS WILL NEED TO KEEP AN EYE ON THIS SYSTEM AS
WELL.

ONE LAST IMPULSE KEEPS A LINGERING CHANCE OF LIGHT SNOW OVER THE
SOUTHWEST THROUGH TUESDAY EVENING...THEN ARCTIC HIGH PRESSURE DROPS
INTO THE AREA AND PUTS AN END TO THE SNOW CHANCES BY LATE TUESDAY
NIGHT. HOWEVER...WIND CHILLS WILL LIKELY AGAIN BE AN ISSUE OVER
MAINLY THE NORTHERN THIRD OF THE FORECAST AREA.

WE THEN WARM UP QUICKLY THURSDAY AS THE ARCTIC HIGH DIVES QUICKLY
SOUTH AND EAST. WE TRANSITION TO A MORE QUASI-ZONAL FLOW WITH
SHORTWAVES TRAVERSING THE AREA FRIDAY AND SATURDAY. WITH THE WARMER
TEMPERATURES WE MAY NEED TO WORRY MORE ABOUT POSSIBLE MIXED
PRECIPITATION BUT TEMPERATURES WILL BE BACK ABOVE NORMAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 637 AM CST SAT JAN 31 2015

MVFR TO IFR CIGS WILL CONTINUE OVER THE AREA THROUGH THE FORECAST
PERIOD. SNOW HAS DEVELOPED IN THE FAR NORTH AND WILL SPREAD SOUTH
AND EAST ACROSS ALL AERODROMES THROUGH THE DAY. AREAS OF DENSE FOG
SOUTHWEST INCLUDING KDIK SHOULD LIFT BY AROUND 15 UTC.

&&

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

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.