Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 231939
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
239 PM CDT SAT MAY 23 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 237 PM CDT SAT MAY 23 2015

THE MAIN FOCUS FOR THE SHORT TERM IS TIMING AND AREAL COVERAGE
OF RAIN TONIGHT AND SUNDAY.

THE LATEST MODEL TRENDS INDICATE YET MORE DELAY IN TIMING OF THE
ONSET OF RAIN MOVING NORTHWARD FROM THE LARGE STORM SYSTEM CENTERED
OVER COLORADO.

THE GFS MODEL REMAINS THE MOST AGGRESSIVE IN BRINGING MEASURABLE
PRECIPITATION ACROSS THE STATE...ALREADY INDICATING THAT RAIN
SHOULD BE ADVANCING NORTH TOWARDS I-94. THIS MODEL WAS DISCOUNTED
FOR TODAY`S FORECAST. INSTEAD USED A BLEND OF THE NAM...ECMWF...HRRR
AND CANADIAN MODELS IN DETERMINING CLOUD AND PRECIPITATION ADVANCEMENT
NORTHWARD. LOW CLOUDS REMAINED STEADY BROKEN/OVERCAST AT HETTINGER
THIS AFTERNOON...WITH OVERCAST SKIES REACHING DICKINSON AND NEARLY
AT BISMARCK. RADAR RETURNS FROM THE BOWMAN RADAR HAVE BEEN
INCREASING WITH INTENSITY AND AREAL COVERAGE THROUGHOUT THE DAY.
NOTED THAT BISON SD RECEIVED 0.01 OF RAIN EARLY THIS
AFTERNOON...THUS PRECIPITATION IS NOW FINALLY REACHING THE GROUND.
EXPECT THAT THE BOWMAN AREA IS SEEING SOME SCATTERED LIGHT RAIN.

CURRENT THINKING IS THAT SHOWERS IN THE FAR SOUTHWEST SHOULD BECOME
MORE NUMEROUS DURING THE EVENING...AND THAT SCATTERED RAIN SHOULD
SPREAD NORTH AND EAST WITH TIME. THE MODELS WERE KEYING IN ON
THE UPPER LEVEL LOW REMAINING SOUTHWEST OF THE STATE TONIGHT...
MAINLY OVER THE FRONT RANGE OF COLORADO AND WYOMING...WITH MORE
OF THE ENERGY AND ASSOCIATED MOISTURE REMAINING FARTHER WEST OVER
THE SOUTHWEST PORTION OF NORTH DAKOTA. HELD OFF WITH HIGHER PRECIP
CHANCES OVER MUCH OF THE JAMES VALLEY UNTIL AROUND DAYBREAK SUNDAY.

ON SUNDAY THE SOUTH HALF OF THE STATE IS LIKELY TO SEE RAIN...WITH
INCREASING CHANCES FARTHER NORTH WITH TIME...BUT THE NORTHERN TIER OF
COUNTIES ALONG THE CANADIAN BORDER WILL HAVE LESS THAN 50 PERCENT
CHANCES OF RAIN. SURFACE AND BOUNDARY LAYER INSTABILITY INCREASES
THROUGH THE MORNING WITH BETTER FORCING AND CAPE. WILL HAVE A
SLIGHT CHANCE MENTION OF THUNDER SUNDAY MORNING...AND FOR THE CHANCE
OF SCATTERED THUNDERSTORMS IN NUMEROUS RAIN SHOWERS SOUTH IN
THE AFTERNOON.

EXPECTING ONLY A TENTH OR TWO TENTHS OF AN INCH OF RAIN TONIGHT SOUTHWEST.
EXPECTING 0.25 TO 0.50 SOUTHWEST ON SUNDAY WITH 0.20 TO 0.40 OVER THE
REST OF SOUTH CENTRAL NORTH DAKOTA SUNDAY. LESSER AMOUNTS FARTHER NORTH.

LOWS TONIGHT FROM 45 TO 50 MOST AREAS IN CLOUD COVER. HIGHS SUNDAY
FROM THE UPPER 50S TO MID 60S SOUTH...AND UPPER 60S TO 70 NORTH.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 237 PM CDT SAT MAY 23 2015

UNSETTLED WEATHER FOR MUCH OF THE LONG TERM PERIOD. RELIED MORE ON
THE ECMWF VERSUS THE GFS BEFORE THE SUPERBLEND TOOK OVER TUESDAY
AFTERNOON THROUGH SATURDAY. THE GFS HAS BEEN CONSISTENTLY OVER-
FORECASTING AREAL COVERAGE OF RAINFALL AND ASSOCIATED AMOUNTS. PER
ECMWF...A NEARLY VERTICALLY STACKED SYSTEM FROM THE SHORT TERM
PERIOD WILL GRADUALLY LIFT FROM SOUTHEAST WYOMING SUNDAY NIGHT TO
EASTERN MINNESOTA BY MONDAY AFTERNOON. LIKELY SHOWERS AND A SLIGHT
CHANCE FOR THUNDERSTORMS DURING THIS TIME...FAVORING CENTRAL AND
SOUTHERN NORTH DAKOTA...WITH LESSER CHANCES IN THE NORTH. FOR MONDAY
NIGHT THROUGH SATURDAY...A PROGRESSIVE PATTERN WITH A MID LEVEL
SHORTWAVE ALMOST ON A DAILY BASIS. THE DAYS WITH THE LOWEST
PROBABILITIES FOR PRECIPITATION AND HENCE MOSTLY A DRY FORECAST
RESIDE IN THE MONDAY NIGHT THROUGH TUESDAY NIGHT PERIOD...AND  ON
SATURDAY. WEDNESDAY THROUGH FRIDAY FAVOR HIGHER CHANCES FOR SHOWERS
AND POSSIBLE THUNDERSHOWERS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1225 PM CDT SAT MAY 23 2015

VFR CONDITIONS ARE EXPECTED AT KMOT THROUGH THE TAF PERIOD...WITH
VFR AT KISN UNTIL AROUND 06Z WHEN MVFR CIGS FORECAST.
VFR CONDITIONS WILL LIKELY DETERIORATE TO MFVR CIGS AT KDIK/KBIS
AROUND 00Z WITH VCSH...AND MVFR CIGS AND VSBYS WITH RAIN BY AROUND
04Z-06Z. KJMS TO BECOME MVFR LATER TONIGHT WITH RAIN.


&&

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

$$

SHORT TERM...JV
LONG TERM...KS
AVIATION...JV



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