Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 120556
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1256 AM CDT SAT APR 12 2014

.UPDATE...
ISSUED AT 1257 AM CDT SAT APR 12 2014

RADAR RETURNS IN THE PAST HOUR OR SO SHOWED INCREASING INTENSITY
OVER THE EASTERN THIRD OF THE STATE. THIS APPEARS TO BE ASSOCIATED
WITH AN UPPER LEVEL IMPULSE PROGGED BY THE MODELS TO INCREASE IN
INTENSITY AS IT MOVES EAST ACROSS THE STATE. MORE SHORTWAVE ENERGY
TO THE WEST OVER MONTANA AND IN WESTERN NORTH DAKOTA AND
SOUTHEASTERN SASKATCHEWAN IS PROGGED TO MOVE EASTWARD THROUGH THE
UPPER LEVEL FLOW DURING THE EARLY MORNING HOURS AND CONTINUING AFTER
SUNRISE. THUS EXPECT MORE PRECIPITATION DEVELOPMENT. VIRGA HAD
DEVELOPED DURING THE EVENING HOURS...AND HAD THE ATMOSPHERE AT LOWER
LEVELS BEEN NOT QUITE SO DRY...LIGHT PRECIPITATION WOULD HAVE
REACHED THE GROUND OVER WESTERN AND CENTRAL NORTH DAKOTA. THINKING
THAT OVERNIGHT THE UPPER LEVEL SHORTWAVE ENERGY AND CONTINUED
EASTERLY FLOW AT THE SURFACE WOULD RESULT IN SCATTERED SHOWERS SOUTH
AND MORE NUMEROUS SHOWERS NORTH. ONLY MINOR CHANGES WITH THIS UPDATE
IN SOME OVERNIGHT LOW TEMPERATURES BASED ON HOURLY TRENDS.

UPDATE ISSUED AT 1009 PM CDT FRI APR 11 2014

CONTINUED TO DELAY THE ONSET OF PRECIPITATION UNTIL LATER TONIGHT
AS THE LOW-LEVELS REMAIN RELATIVELY DRY. TEMP/DEWPOINT SPREADS
ARE RANGING FROM 10-15 DEGREES ALONG AND WEST OF HIGHWAY 83...WITH
5 DEGREE TEMP/DEWPOINT SPREADS EAST OF HIGHWAY 83.

WATER VAPOR IMAGERY DEPICTS A SHORTWAVE MOVING EAST ALONG THE
INTERNATIONAL BOUNDARY OVER SOUTH CENTRAL SASKATCHEWAN. THIS WAVE
SHOULD SERVE AS A TRIGGER FOR PRECIP DEVELOPMENT LATER TONIGHT. A
CHANGEOVER TO SNOW IS STILL EXPECTED OVER THE TURTLE MOUNTAINS
WELL AFTER MIDNIGHT.

UPDATE ISSUED AT 722 PM CDT FRI APR 11 2014

REGIONAL RADARS ARE DEPICTING PRECIPITATION DEVELOPING OVER
WESTERN AND CENTRAL NORTH DAKOTA LATE THIS AFTERNOON.
HOWEVER...NONE OF THIS ACTIVITY IS REACHING THE SURFACE. THE 00Z
KBIS SOUNDING SHOWS A VERY DRY LAYER FROM THE SURFACE UP TO AROUND
700MB. MOST...IF NOT ALL...PRECIPITATION IS EVAPORATING BEFORE
REACHING THE SURFACE.

AS A RESULT...LOWERED POPS A BIT THROUGH THE EARLY EVENING
HOURS...THEN MAINTAINED THE CURRENT POP FORECAST FOR THE LATE
EVENING/OVERNIGHT HOURS AS WET BULB COOLING SHOULD AID IN
SATURATING THE BOUNDARY LAYER. THE REMAINING FORECAST IS ON TRACK
WITH NO OTHER MAJOR UPDATES REQUIRED. THE UPDATED PRODUCTS HAVE
BEEN SENT.

&&

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

ISSUED AT 301 PM CDT FRI APR 11 2014

THE MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD IS
PRECIPITATION TYPE/AMOUNTS ACROSS THE FAR NORTH FOR TONIGHT INTO
SATURDAY.

BOUNDARY LAYER TEMPERATURES ARE EXPECTED TO PRECLUDE SNOW
ACCUMULATIONS ACROSS ALL BUT THE FAR NORTH. THE LATEST WINTER
WEATHER DESK GUIDANCE INDICATES BORDERLINE ADVISORY AMOUNTS IN THE
TURTLE MOUNTAINS AREA...GENERALLY 2 TO 4 INCHES. TIMING OF THE
RAIN TO SNOW CHANGE OVER WILL BE CRITICAL. THUS...CONFIDENCE NOT
THAT HIGH IN GETTING A SIGNIFICANT AREA WITH 3+ INCHES...WHICH
WOULD WARRANT AN ADVISORY. THE 11/12Z ECMWF IS LESS BULLISH WITH
TOTAL QPF NORTH COMPARED TO PREVIOUS RUNS...BUT DOES SPREAD UP TO
A QUARTER INCH OF RAIN FARTHER SOUTH. HAVE BUMPED UP POPS FOR
TONIGHT AND SATURDAY...ESPECIALLY NORTH. STRONG COLD AIR ADVECTION
WILL BEGIN BY LATE SATURDAY MORNING IN THE NORTHWEST...THEN SPREAD
SOUTHEAST ACROSS THE STATE THROUGH THE DAY. THE DAY TIME
TEMPERATURE REBOUND WILL BE LIMITED NORTH...BUT AFTERNOON READINGS
SHOULD BE ABLE TO RECOVER INTO THE 50S SOUTH AHEAD OF THE COLD AIR
SURGE. ADVISORY CRITERIA WINDS NOT ANTICIPATED AT THIS TIME
THROUGH SATURDAY AFTERNOON...BUT HAVE INCREASED SPEEDS A FEW MPH
FROM THE BLENDED GUIDANCE.

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

ISSUED AT 301 PM CDT FRI APR 11 2014

UPPER LEVEL FLOW PATTERN TRANSITIONS TO A CYCLONIC FLOW ALOFT SAT
NIGHT INTO SUNDAY...FOLLOWED BY NORTHWESTERLY FLOW EARLY TO MID
NEXT WEEK.

LINGERING RAIN OR SNOW CONTINUES SATURDAY NIGHT NORTHEAST ACROSS
THE WESTERN DEVILS LAKE BASIN/TURTLE MOUNTAIN REGION BEFORE
ENDING BY SAT NIGHT/EARLY SUNDAY. S/WV MID LEVEL TROUGH SWINGS
SOUTHEAST THROUGH THE NORTHERN PLAINS ON SUNDAY BRINGING A
REINFORCED SHOT OF COLD AIR. SFC FORCING WILL BE PRESENT WITH A
SUBTLE SFC TROUGH/AREA OF LOW PRESSURE MOVING SOUTH ACROSS THE
LOCAL AREA. EXPANDED THE AERIAL COVERAGE OF LOW POPS AS WILL
LIKELY SEE A RAIN OR SNOW SHOWER WITH THE UPPER TROUGH PASSAGE.
HIGHS SUNDAY ON THE CHILLY SIDE...LOW 30S-AROUND 40.

MODELS TREND TOWARDS DISARRAY NEXT WEEK REGARDING THE
EVOLUTION/TRACK OF DEEP LOW PRESSURE OVER THE HUDSON BAY IN
ADDITION TO EMBEDDED WAVES ORIGINATING OVER THE PACIFIC TRACKING
EAST THROUGH THE PACIFIC NORTHWEST AND ACROSS THE ROCKIES. STUCK
WITH THE ALLBLEND OUTPUT. MORE CERTAINTY THAT COLDER THAN NORMAL
TEMPERATURES WILL REMAIN OVER THE NORTHERN PLAINS INTO NEXT WEEK
WITH NORTHWESTERLY FLOW ALOFT AND A LACK OF WAA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1257 AM CDT SAT APR 12 2014

EXPECT MAINLY MID LEVEL CLOUDS AND VIRGA TO BECOME MVFR CEILINGS
NORTH (KISN-KMOT) IN THE NEXT COUPLE OF HOURS. SHOWERS WILL
CONTINUE TO DEVELOP OVER WESTERN AND CENTRAL NORTH DAKOTA
TONIGHT...AND SHOULD DIMINISH FROM WEST TO EAST SATURDAY MORNING.
BREEZY TO WINDY CONDITIONS ARE EXPECTED BY SATURDAY AFTERNOON.
WINDY CONDITIONS CONTINUING INTO THE EVENING AS STRONGER COLD
ADVECTION BEGINS WITH CIGS BECOMING MVFR.

&&

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

$$

UPDATE...JV
SHORT TERM...RP KINNEY
LONG TERM...NH
AVIATION...JV






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