Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 230008
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
608 PM CST SAT NOV 22 2014

.UPDATE...
ISSUED AT 607 PM CST SAT NOV 22 2014

AN AREA OF LIGHT RAIN CONTINUES TO MOVE ACROSS CENTRAL NORTH
DAKOTA AT THIS HOUR...WITH OTHER LIGHT ECHOES SHOWN BY AREA RADARS
IN EASTERN MONTANA. SHORT TERM MODELS SOLUTIONS INCLUDING THE
HRRR...SUPPORT A GENERAL DECLINE IN THE PRECIPITATION THIS
EVENING IN CENTRAL NORTH DAKOTA...WHILE THE PRECIPITATION IN
EASTERN MONTANA EVENTUALLY ARRIVES IN THE WESTERN PART OF THE
STATE. HAVE GENERALLY DECEASED POPS IN THE VERY NEAR TERM IN PARTS
OF THE NORTHWEST...AND TRIED TO SURROUND THE ONGOING PRECIPITATION
IN THE CENTRAL WITH SLIGHTLY HIGHER POPS. PRECIPITATION AMOUNTS
HAVE GENERALLY BEEN A TRACE TO 0.01...SO DO NOT EXPECT MUCH
ACCUMULATION WITH THIS INITIAL ROUND.

PRECIPITATION TYPE REMAINS A BIT CHALLENGING...WITH SURFACE
TEMPERATURES SLOWLY FALLING THIS EVENING WHICH COULD LEAD TO A
PERIOD OF FREEZING RAIN. THE GOOD NEWS IS MODEL SOLUTIONS SUGGEST
A SLOW TEMPERATURE DECLINE...SO CURRENT THINKING IS ANY FREEZING
RAIN SHOULD BE VERY LIGHT AND BRIEF. THERE COULD ALSO BE A BRIEF
PERIOD OF SLEET AS COLDER AIR ARRIVES BEHIND A COLD FRONT LATER
THIS EVENING / TONIGHT. MODEL QPF IS LIGHT...SO AGAIN THINKING IS
AMOUNTS SHOULD BE VERY LIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)

ISSUED AT 342 PM CST SAT NOV 22 2014

SHORT TERM CHALLENGE INVOLVES WINTER WEATHER AND WINDS. SURFACE
LOW ACROSS ALBERTA WILL TRACK EAST TONIGHT THROUGH SUNDAY.
CURRENTLY A WARM FRONT ACROSS SOUTHEAST MONTANA IS THE FOCUS FOR
RAIN FOR SOUTHWEST NORTH DAKOTA AS TEMPERATURES REMAIN IN THE
UPPER 30S TO MIDDLE 40S THIS AFTERNOON. BY THIS EVENING AS
TEMPERATURES COOL BUT BOUNDARY LAYER TEMPERATURES REMAIN ABOVE
FREEZING WILL SOME SOME POTENTIAL FOR A BRIEF PERIOD OF FREEZING
RAIN ACROSS THE WEST. TONIGHT THE RAIN CHANCES WILL CHANGE TO SNOW
CHANCES WITH A BRIEF PERIOD OF FREEZING RAIN POTENTIAL MAINLY
NORTH. BY SUNDAY MORNING THE COLD FRONT WILL APPROACH AND ALL
SNOW IS EXPECTED WITH INCREASING WINDS. DEBATED THE MERITS OF A
SNOW AND BLOWING SNOW ADVISORY ACROSS THE NORTH CENTRAL WHERE 1 OR
2 INCHES OF SNOW IS POSSIBLE HOWEVER DECIDED FOR A WIND ADVISORY
AS SUFFICIENT SNOW POTENTIAL IS LOW. WILL BREAK OFF THE NORTHERN
PORTION...ALONG HIGHWAY 2 AND NORTH AND MENTION SOME SNOW AND
BLOWING SNOW IN THE WIND ADVISORY FOR SUNDAY. OTHERWISE SUNDAY WILL
BE BLUSTERY WITH SNOW LIKELY NORTH AND CHANCE FOR SNOW SOUTH.
TEMPERATURES WILL FALL DURING THE DAY SUNDAY AND WINDS WILL BE 25
TO 45 MPH. WAS CONCERNED ABOUT A 9-11 MB PRESSURE RISE SUNDAY
AFTERNOON NORTH AS THE COLDER AIR ARRIVES. COULD GET SOME GUSTY
WINDS SUNDAY AFTERNOON FROM CROSBY TO MINOT TO ROLLA. SUNDAY NIGHT
WINDS WILL DIMINISH WEST CENTRAL AND MAY STILL BE A BIT GUSTY JAMES
RIVER VALLEY.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)

ISSUED AT 342 PM CST SAT NOV 22 2014

MEDIUM RANGE MODELS HAVE AGAIN SHIFTED FOR MID-LATE NEXT
WEEK...NOW TRENDING BACK COLDER AS BOTH THE 12Z GFS/ECMWF DEPICT
A NORTHWEST FLOW ALOFT VERSUS PREVIOUS RUNS WHICH SHOWED A BUILDING
UPPER LEVEL RIDGE INTO THE REGION. THIS WILL HAVE A DRAMATIC
IMPACT ON FORECAST TEMPERATURES WEDNESDAY-SATURDAY ALONG WITH SNOW
CHANCES.

REMOVED SNOW MENTION FOR MONDAY MORNING WITH WRAP AROUND MOISTURE
MORE OVER THE EASTERN DAKOTAS AND UPPER MIDWEST. SOME VERY LIGHT
SNOW/FLURRIES WILL BE POSSIBLE MONDAY AFTERNOON-EVENING WHEN
MODELS DEPICT A SUBTLE EMBEDDED S/WV MOVING THROUGH THE FLOW
ALOFT. THIS REPEATS ON TUESDAY WITH ANOTHER AREA OF LIGHT SNOW
MOVING FROM NORTHWEST TO SOUTHEAST ACROSS THE NORTHERN PLAINS
ASSOCIATED WITH AN AREA OF WEAK LOW PRESSURE. TEMPERATURES DO
REBOUND TUESDAY AS SOME WEAK WAA MOVES INTO THE WESTERN HALF OF
THE STATE AHEAD OF THE SFC LOW.

TRENDED THE THANKSGIVING HOLIDAY COLDER WITH THE PATTERN SHIFT TO
MORE NORTHWEST VERSUS ZONAL.

OF MAIN INTEREST AND A RECENT DEVELOPMENT WILL BE THE POSSIBILITY
OF ACCUMULATING SNOWFALL FROM MONTANA THROUGH SOUTHWEST NORTH
DAKOTA (POSSIBLY OVER THE ENTIRE SOUTHWESTERN HALF OF THE
STATE)...WHICH WOULD CREATE IMPACTS TO HOLIDAY TRAVEL. BOTH THE
12Z GFS/ECMWF ARE NOW SHOWING A QUASI-STATIONARY FRONTAL BOUNDARY
DRAPED NORTHWEST TO SOUTHEAST FROM NORTHERN MONTANA THROUGH
SOUTHWEST ND/WESTERN SOUTH DAKOTA. ALOFT A STRONG JET STREAK WILL
INTERACT WITH THE SFC BOUNDARY TO PRODUCE A SWATH OF ACCUMULATING
SNOWFALL UNDER STRONG THERMAL LIFT ALONG TO EAST OF THE FRONT.
THE MAIN DIFFERENCES BETWEEN THE GFS AND EC ARE PLACEMENT...WITH
THE GFS FARTHER NORTH AND EAST GIVING A GOOD SHOT OF SNOWFALL TO
WESTERN AND SOUTH CENTRAL PARTS OF THE STATE. THE ECMWF IS MORE
SOUTH AND WEST AND KEEPS MOST OF THE SNOW CONFINED TO THE
SOUTHWEST CORNER. CONFIDENCE LOW AT THIS POINT CONSIDERING THE
RATHER SIGNIFICANT MODEL FLIP FLOPS OVER THE PAST 48 HOURS.
SHOULD ALSO NOTE THE 12Z GEM IS VERY SIMILAR TO THE ECMWF. WILL
CONTINUE TO MONITOR...AND WILL NOT HIGHLIGHT IN ANY PRODUCTS AT
THIS TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 607 PM CST SAT NOV 22 2014

VERY LIGHT RAIN IS POSSIBLE THIS EVENING FROM KMOT AND KBIS TO
PERHAPS KJMS. VFR CONDITIONS WILL PREVAIL INITIALLY...HOWEVER MVFR
LEVEL CLOUDS WILL MOVE IN BEHIND A COLD FRONT. LIGHT SNOW AND
BLOWING SNOW ARE POSSIBLE SUNDAY. THERE IS A SMALL CHANCE OF MIXED
PRECIPITATION THIS EVENING...BUT FOR NOW KEPT THAT OUT OF THE TAFS
SINCE THE CHANCES APPEAR RELATIVELY SMALL. WINDS WILL TURN WEST /
NORTHWEST BEHIND THE COLD FRONT AND BECOME GUSTY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CST /9 AM MST/ SUNDAY TO MIDNIGHT CST
/11 PM MST/ SUNDAY NIGHT FOR NDZ001>005-009>013-017>023-031>035-
040>045.

&&

$$

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






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