Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 280530
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1230 AM CDT THU APR 28 2016

.UPDATE...
ISSUED AT 1222 AM CDT THU APR 28 2016

NO MAJOR CHANGES REQUIRED FOR THIS UPDATE. LIGHT SNOW CONTINUES
ACROSS FAR SOUTHWESTERN NORTH DAKOTA. AN ADDITIONAL INCH OR SO OF
SNOW IS POSSIBLE THROUGH THE EARLY MORNING HOURS. TRAVEL IS NOT
ADVISED ACROSS BOWMAN...SLOPE...ADAMS AND HETTINGER COUNTIES DUE
TO SLICK...SLUSHY ROADS.

UPDATE ISSUED AT 924 PM CDT WED APR 27 2016

FOR LATE EVENING UPDATE HAVE TAKEN GOLDEN VALLEY AND BILLINGS
COUNTIES OUT OF THE WINTER WEATHER ADVISORY. WEBCAMS AND OBS IN
THE AREA SUGGEST MOST OF THE SNOW HAS ENDED. WILL KEEP REMAINDER
GOING AS BOWMAN NDARB RADAR CONTINUES TO SHOW A BROAD AREA OF
ENHANCED REFLECTIVITY MOVING THROUGH THE FAR SOUTHWEST. HAVE ALSO
PUT A MENTION OF PATCHY FOG OVER THE SOUTHWEST GIVEN THE FRESH
SNOWFALL THAT HAS BEEN DOING SOME MELTING. UPDATES HAVE BEEN SENT.

UPDATE ISSUED AT 630 PM CDT WED APR 27 2016

FOR EARLY EVENING UPDATE HAVE PULLED HIGHER PRECIPITATION CHANCES
A BIT FURTHER NORTH IN LINE WITH LATEST RADAR TRENDS.
OTHERWISE...PREVIOUS FORECAST REMAINS IN GOOD SHAPE WITH WINTER
HEADLINES CONTINUING OVER THE FAR SOUTHWEST.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 401 PM CDT WED APR 27 2016

THE FOCUS OF THE SHORT TERM FORECAST IS ON THE LINGERING SNOW IN
SOUTHWEST ND...AND RAIN SOUTH CENTRAL...TONIGHT AND THURSDAY.

OVERALL...THE GOING FORECAST IS ON TRACK. AS OF 2045 UTC...WARMER
AIR ALOFT HAS WORKED FAR ENOUGH WEST TO CAUSE A CHANGE FROM SNOW
TO RAIN IN DICKINSON. BASED ON THAT CHANGE-OVER AND TRENDS IN THE
BOWMAN RADAR IMAGERY...WE CANCELLED THE WINTER WEATHER ADVISORY
FOR STARK COUNTY. THE REMAINDER OF THE ADVISORY WAS CONTINUED AS-
IS...THOUGH NORTHERN PIECES OF THAT /BILLINGS AND GOLDEN VALLEY
COUNTIES AT THE LEAST/ WILL LIKELY BE CANCELLED EARLY. SNOWFALL
INTENSITY HAS LESSENED SINCE ABOUT 18 UTC BASED ON RADAR IMAGES
AND ASOS/AWOS VISIBILITY TRENDS...WHICH IS CONSISTENT WITH WANING
FORCING ALOFT AS MID-LEVEL FRONTOGENESIS WEAKENS. RECENT RAP/HRRR
GUIDANCE...AS WELL AS OTHER HIGH-RESOLUTION GUIDANCE LIKE THE 12
UTC WRF-ARW AND WRF-NMM THAT HAS BEEN HANDLING THE SITUATION WELL
TODAY...ALL CONCURS WITH THAT WEAKENING TREND. THUS...ONLY MINOR
ADDITIONAL SNOW ACCUMULATIONS ARE EXPECTED ACROSS SOUTHWEST ND BY
THURSDAY MORNING.

PER SPOTTERS AND EMERGENCY MANAGEMENT OFFICIALS...A WIDESPREAD 3
TO 5 INCH SNOWFALL HAS OCCURRED IN SOUTHWEST ND SO FAR TODAY. THE
SNOW HAS...HOWEVER...BEEN SETTLING AND MELTING SOME ON THE GROUND.
MOREOVER...MOST ROADS HAVE BECOME WET THIS AFTERNOON...REDUCING
TRAVEL IMPACTS. THEREFORE...EVEN THOUGH SOME LOCALIZED AMOUNTS IN
EXCESS OF OUR TRADITIONAL 6 INCH/12 HOUR CRITERIA FOR ISSUANCE OF
A WINTER STORM WARNING ARE LIKELY...THE IMPACTS HAVE NOT BEEN
SUFFICIENT TO UPGRADE TO A WARNING ANYWHERE. NOTE HOWEVER THAT WE
DO BELIEVE SOME OF THE WET ROADS WILL LIKELY FREEZE TONIGHT /EVEN
AFTER THE PRECIPITATION HAS ENDED/...SO THERE MAY BE ADDITIONAL
TRAVEL IMPACTS. FINALLY...WE DID INCLUDE A SLIGHT CHANCE OF LIGHT
FREEZING RAIN IN THE GRIDDED FORECAST OVER A SMALL PORTION OF
SOUTHWEST ND TONIGHT AS THE WARM LAYER ALOFT IS FORECAST TO EXCEED
+3 C AS WEAK THETA-E ADVECTION CONTINUES ALOFT.

FINALLY...THURSDAY WILL BE A RELATIVELY QUIET WEATHER DAY...WITH A
LINGERING CHANCE OF PRECIPITATION IN SOUTHWEST AND SOUTH CENTRAL
ND. HIGHS ARE FORECAST TO RANGE FROM THE MID 40S IN SOUTHWEST ND
TO THE MID 50S NORTH CENTRAL BASED ON THE 12 UTC MODEL CONSENSUS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 401 PM CDT WED APR 27 2016

THE KEY MESSAGE WE WANT TO CONVEY IN THE LONG TERM FORECAST PERIOD
IS THAT A DRIER AND WARMER WEATHER PATTERN IS LIKELY NEXT WEEK.

ON THE LARGE SCALE...RECENT GFS AND ECMWF RUNS AND THEIR ENSEMBLES
HAVE AGREED WELL IN SUGGESTING A BREAKDOWN OF THE COMPLEX...BLOCKY
FLOW ALOFT THAT HAS BEEN IN PLACE ACROSS NORTH AMERICA RECENTLY. A
BLOCKING PATTERN LIKE THIS ONE OFTEN TAKES TIME TO DISSOLVE...BUT
THE MAIN THEME IN THE 00 AND 12 UTC MODEL SIMULATIONS IS FOR MEAN
500-MB RIDGING TO TAKE HOLD OVER THE NORTHERN PLAINS BY EARLY NEXT
WEEK. IN FACT...TAKEN AT FACE VALUE THE 12 UTC ECMWF AND GFS BOTH
SUGGEST A PASSING REX BLOCK WILL DEVELOP THIS WEEKEND WITH A RIDGE
OVER SOUTHERN CANADA NUDGING INTO ND...SUPPRESSING THE NEXT TROUGH
THAT CROSSES THE CENTRAL PLAINS AND REDUCING THE CHANCE OF RAIN IN
ND. HOWEVER...THAT PARTICULAR TIMEFRAME IS A LOWER-CONFIDENCE PART
OF THE FORECAST AS THERE HAS BEEN RATHER CONSIDERABLE WOBBLING IN
THE GUIDANCE WITH HOW FAR NORTH THE INFLUENCE OF THAT TROUGH WILL
BE FELT. THUS...AT THIS POINT WE ARE MAINTAINING A CHANCE OF RAIN
IN THE FORECAST SATURDAY...MAINLY ALONG AND TO THE SOUTH OF
INTERSTATE 94.

REGARDLESS OF WHAT OCCURS THIS WEEKEND...THERE IS RELATIVELY GOOD
AGREEMENT THAT MID-LEVEL TEMPERATURES WILL WARM BENEATH THE MEAN
RIDGING NEXT WEEK. OUR FORECAST IS CALLING FOR HIGHS SOLIDLY BACK
INTO THE 60S F MONDAY THROUGH WEDNESDAY PER A CONSENSUS OF THE 12
UTC MODEL GUIDANCE. THAT FORECAST IS WELL-SUPPORTED BY MOS OUTPUT
FROM THE 00 AND 12 UTC GFS AND ECMWF AND THEIR ENSEMBLE MEMBERS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1222 AM CDT THU APR 28 2016

VFR AT ALL TAF SITES THROUGH THE TAF PERIOD. KBIS MAY FLIRT WITH
MVFR CONDITIONS TODAY AS LIGHT RAIN MOVES IN ACROSS SOUTHERN NORTH
DAKOTA. FOR NOW SHORT TERM MODELS KEEP THE BULK OF THE LOW STRATUS
AND RAIN SOUTH OF THE BISMARCK AREA SO ELECTED TO KEEP ANY
MENTION OUT OF THE TAF AT THIS TIME.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR NDZ040-041-
043-044.

&&

$$

UPDATE...AJ
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...AJ



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