Area Forecast Discussion
Issued by NWS Bismarck, ND

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467
FXUS63 KBIS 271334
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
834 AM CDT WED APR 27 2016

.UPDATE...
ISSUED AT 834 AM CDT WED APR 27 2016

QUICK UPDATE TO ISSUE A WINTER WEATHER ADVISORY FOR SOUTHWEST ND
THROUGH 12 UTC THURSDAY MORNING. VISIBILITIES AT BOTH DICKINSON
AND HETTINGER HAVE FALLEN TO 1/2SM IN MODERATE SNOW AS OF 13 UTC
AND WEB CAMERAS SHOW SNOW STICKING TO ROADS...CAUSING IMPACTS TO
TRAVEL. GIVEN THE ONGOING SNOWFALL INTENSITY...WE INCREASED SNOW
AMOUNTS IN THE FORECAST TO BETWEEN 3 AND 6 INCHES. CONFIDENCE IN
THE TOTAL SNOWFALL IS MODEST AT BEST GIVEN UNCERTAINTY WITH WHEN
SNOW MAY CHANGE TO RAIN AND HOW MUCH MELTING AND COMPACTION MAY
OCCUR TODAY WITH RELATIVELY WARM GROUND. BASED ON AN IN-HOUSE SET
OF PROBABILITY GUIDANCE FROM RECENT MODEL OUTPUT...THERE IS ABOUT
A 20 OR 30 PERCENT PROBABILITY OF GREATER THAN 6 INCHES OF SNOW IN
FAR SOUTHWEST ND...NAMELY BOWMAN AND HETTINGER COUNTIES....SO WE
WILL NEED TO MONITOR CLOSELY FOR A POTENTIAL UPGRADE TO A WINTER
STORM WARNING IN SOME AREAS.

UPDATE ISSUED AT 645 AM CDT WED APR 27 2016

MADE SOME MINOR ADJUSTMENTS TO POPS BASED ON LATEST RADAR
ANALYSIS. OTHERWISE NO SIGNIFICANT UPDATES WARRANTED. DID ISSUE A
SPS BEFORE THE UPDATE FOR SOME SNOW ACCUMULATIONS OVER SOUTHWEST
NORTH DAKOTA THIS MORNING AND AGAIN TONIGHT. LATEST MESOSCALE
MODELS ARE HITTING THE SOUTHWEST PRETTY HARD WITH SNOW
ACCUMULATIONS THROUGH THE DAY TODAY. LATEST RAP/HRRR DO SHOW AN
AREA OF STRONG OMEGA THIS MORNING WITHIN THE SNOW GROWTH ZONE
ACROSS SOUTHWEST NORTH DAKOTA. BASED ON THIS WE UPDATED SNOW
AMOUNTS TO THE 1-3 INCH RANGE OVER A GOOD PORTION OF THE
SOUTHWEST. THE MESOSCALE MODELS ARE BANKING ON PRECIPITATION
REMAINING SNOW THROUGH THE DAY AND WITH FORECAST HIGHS IN THE MID
30S THIS CAN NOT BE RULED OUT. WILL BRIEF THE UPCOMING SHIFT BUT
FOR NOW WILL STICK WITH GENERALLY A 1-3 INCH RANGE IN GRASSY AREAS
WITH NOT MUCH ACCUMULATION DURING THE AFTERNOON HOURS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 304 AM CDT WED APR 27 2016

THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE
PRECIPITATION POTENTIAL...PLACEMENT AND TYPE. GLOBAL MODEL QPF
DIFFERENCES REMAIN TODAY WITH THE ECMWF MORE BULLISH WITH QPF INTO
SOUTHWEST AND FAR SOUTH CENTRAL NORTH DAKOTA. THE NAM/GFS ARE NOT
AS FAR EAST AND NORTH WITH THE HIGHER QPF AMOUNTS. ALL DO INDICATE
THE SOUTHWEST AND FAR SOUTH CENTRAL WILL BE THE MOST LIKELY AREA
FOR QPF SO HAVE ADJUSTED POPS ACCORDINGLY. THE BIGGEST CHANGE FROM
THE PREVIOUS FORECAST WAS LOWERING POPS OVER THE JAMES RIVER
VALLEY AND NORTHWARD INTO NORTH CENTRAL NORTH DAKOTA. EXCEPT FOR
THE FAR SOUTHERN TIER COUNTIES OF DICKEY AND MCINTOSH ALONG THE SD
BORDER...POPS ARE MAINLY CHANCE TO SLIGHT CHANCE HERE WITH DRY
CONDITIONS OVER THE TURTLE MOUNTAINS.

THE POP CHANGES ALSO RESULTED IN WARMER TEMPERATURES NORTH AND
EAST WITH MID 50S NORTH CENTRAL. CONTINUED CLOUDY SKIES WITH HIGHER
POPS SOUTHWEST YIELDED ONLY MID TO UPPER 30S FOR A GOOD PORTION
OF THE SOUTHWEST.

CURRENT SURFACE OBSERVATIONS ARE INDICATING SOME SNOW OVER THE
SOUTHWEST THIS MORNING. A MULTI-MODEL BLEND OF TEMPERATURES AND
SNOW RATIOS INDICATES SNOW CHANGING TO RAIN OVER THE SOUTHWEST
THIS AFTERNOON...WHEN THE HIGHEST QPF AMOUNTS ARE EXPECTED.
PRECIPITATION THEN CHANGES BACK TO SNOW TONIGHT AS TEMPERATURES
COOL AGAIN...BUT QPF AMOUNTS ALSO DIMINISH. CURRENT SNOW AMOUNTS
ARE INDICATING SOME HALF INCH TO ONE INCH ACCUMULATIONS IN THE
SOUTHWEST THROUGH THIS MORNING. THEN ANOTHER 0.5 TO 1.5 INCHES
OVER THE FAR SOUTHWEST TONIGHT INTO THURSDAY MORNING. WILL NEED TO
MONITOR TEMPERATURES AND PRECIPITATION TODAY IN THE FAR SOUTHWEST.
GIVEN THE HIGHER ELEVATIONS AND FORECAST HIGHS IN THE MID 30S...WE
COULD SEE SOME HIGHER SNOW AMOUNTS IF PRECIPITATION FALLS AS ALL
SNOW DURING THE AFTERNOON HOURS. PRECIPITATION REMAINS CONFINED TO
MAINLY THE SOUTHWEST AND SOUTH CENTRAL TONIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 304 AM CDT WED APR 27 2016

MAINLY DRY AND COOL CONDITIONS HIGHLIGHT THE BEGINNING OF THE LONG
TERM PERIOD...WITH ANOTHER CHANCE OF PRECIPITATION FOR THE WEEKEND
AND THEN WARMING TEMPERATURES NEXT WEEK.

HIGH PRESSURE IN THE UPPER LEVELS STRENGTHENS OVER THE NORTHERN
PLAINS REGION ON THURSDAY AND FRIDAY BRINGING MAINLY DRY
CONDITIONS AND SEASONABLY COOL TEMPERATURES IN THE 40S AND 50S.
ANOTHER UPPER LOW MOVES ONTO THE CALIFORNIA COAST TODAY AND
SLOWLY MAKES ITS WAY INTO THE SOUTHWEST U.S. LATE IN THE WORK
WEEK. THE LOW THEN LIFTS NORTHWARD THROUGH THE CENTRAL PLAINS WITH
THE NORTHERN FRINGES OF THE SYSTEM PUSHING INTO SOUTHERN NORTH
DAKOTA ON SATURDAY. THE LATEST MODEL TRENDS KEEP PRECIPITATION
MAINLY ALONG AND SOUTH OF THE HIGHWAY 200 CORRIDOR SATURDAY
THROUGH SUNDAY WITH QPF AMOUNTS RANGING FROM A QUARTER TO A THIRD
OF AN INCH ALONG THE SOUTH DAKOTA BORDER TO AROUND A TENTH OF AN
INCH ALONG THE I-94 CORRIDOR...AND TAPERING TO TRACE AMOUNTS AS
YOU GO NORTH TO THE HIGHWAY 200 CORRIDOR. THIS WOULD BE FOR THE
TWO DAY PERIOD OF SATURDAY THROUGH SUNDAY. THERE COULD AGAIN BE
SOME LIGHT SNOW DURING THE OVERNIGHT HOURS SATURDAY NIGHT INTO
EARLY SUNDAY MORNING ALONG AND WEST OF THE HIGHWAY 83 CORRIDOR.

HIGH PRESSURE AGAIN BUILDS OVER THE NORTHERN PLAINS EARLY NEXT
WEEK WITH A STRONG UPPER LEVEL RIDGE TRYING TO BECOME ESTABLISHED
OVER A GOOD PORTION OF THE WESTERN U.S TOWARD MID WEEK. THIS
SHOULD BRING MAINLY DRY CONDITIONS WITH SEASONABLE TEMPERATURES IN
THE SIXTIES EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 645 AM CDT WED APR 27 2016

WIDESPREAD IFR CEILINGS EXPECTED TO CONTINUE OVER SOUTHWEST NORTH
DAKOTA THROUGH THE EARLY MORNING HOURS INCLUDING KDIK. AREAS OF
FOG ALSO AT KDIK AND KBIS. MAINLY SNOW AT KDIK WITH VISIBILITIES
UNDER A MILE AT TIMES THIS MORNING. PRECIPITATION EXPECTED TO
REMAIN ALL RAIN AT KBIS. CONDITIONS WILL SLOWLY IMPROVE WEDNESDAY
AFTERNOON. FARTHER NORTH AND EAST...IFR TO MVFR CONDITIONS AT KISN
THROUGH WEDNESDAY MORNING...THEN IMPROVING. MAINLY VFR CONDITIONS
AT KMOT AND KJMS THROUGH THE 06Z TAF PERIOD...BUT OCCASIONAL MVFR
CEILINGS POSSIBLE...ESPECIALLY AT KJMS FROM 12-18 UTC WEDNESDAY.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR NDZ031>033-
040-041-043-044.

&&

$$

UPDATE...CJS
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH



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