Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 310206
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
906 PM CDT SAT MAY 30 2015

.UPDATE...
ISSUED AT 901 PM CDT SAT MAY 30 2015

NO MAJOR CHANGES WERE NEEDED FOR THIS UPDATE. TWEAKED POPS BASED
ON RADAR TRENDS AND HRRR/RAP GUIDANCE. LOWERED HIGH TEMPERATURES
ON SUNDAY BY A DEGREE OR TWO TO ACCOUNT FOR WIDESPREAD CLOUD
COVER IN THE CENTRAL PART OF THE STATE. STILL LOOKS LIKE THE BEST
CHANCES FOR MEASURABLE PRECIPITATION WILL RESIDE IN SOUTHWESTERN
AND SOUTH CENTRAL NORTH DAKOTA OVERNIGHT.

UPDATE ISSUED AT 624 PM CDT SAT MAY 30 2015

CLOUDS CONTINUE TO BE ON THE INCREASE AS BROAD AREA OF SHOWERS
AND A FEW THUNDERSTORMS MOVE THROUGH EASTERN MONTANA. A FEW SMALL
SHOWERS ARE NOTED AHEAD OF THE MAIN SYSTEM MOVING THROUGH WESTERN
NORTH DAKOTA. WILL ADD SOME VERY LOW POPS FOR THESE AS DO NOT
EXPECT MUCH IF ANYTHING PRECIPITATION WISE. OTHERWISE...ONLY
CHANGE TO PREVIOUS FORECAST WAS TO INCREASE POPS A BIT LATER THIS
EVENING TO ACCOUNT FOR TIMING OF THE APPROACHING SYSTEM.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 213 PM CDT SAT MAY 30 2015

THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE
PRECIPITATION CHANCES AND PLACEMENT TONIGHT THROUGH SUNDAY.

MODELS ARE STILL NOT IN COMPLETE AGREEMENT ON PRECIPITATION
PLACEMENT TONIGHT-SUNDAY ASSOCIATED WITH THE SHORTWAVE TROUGH
THAT IS CURRENTLY MOVING INTO WESTERN MONTANA. HOWEVER...THE
GENERAL CONSENSUS IS FOR SHOWERS TO MOVE INTO WESTERN NORTH DAKOTA
02-04 UTC THIS EVENING AND TRACE EAST SOUTHEAST DURING THE
OVERNIGHT HOURS. MAJORITY OF MODELS HIGH WEST CENTRAL INTO
SOUTHWEST NORTH DAKOTA WITH BEST PRECIPITATION CHANCES 06-12 UTC
SUNDAY...THEN SOUTH CENTRAL NORTH DAKOTA...SOUTH OF THE INTERSTATE
12-18Z SUNDAY. A FEW MODELS DO BRING PRECIPITATION CHANCES FARTHER
NORTH ON SUNDAY. BUT ALL MODELS ARE PRETTY LIGHT WITH QPF ACROSS
THE NORTHWEST AND NORTH CENTRAL...THUS AM HEDGING POP CHANCE AND
QPF AMOUNTS TO THE SOUTHERN SOLUTION. LOOKS LIKE ON AVERAGE A
QUARTER INCH OR LESS QPF AMOUNTS. THERE IS SOME LIMITED INSTABILITY
IN THE FAR SOUTHWEST TONIGHT AFTER MIDNIGHT...BUT IN GENERAL THE
PROBABILITY OF THUNDER LOOKS PRETTY LOW. HAD A MENTION OF THUNDER
IN THE EVENING AND NOTHING AFTER MIDNIGHT. WILL PULL THUNDERSTORM
CHANCES FOR TONIGHT.

SUNDAY AFTERNOON...SOME MODELS STILL WANT TO LINGER SOME LIGHT QPF
ACROSS THE SOUTH CENTRAL. LOW TO MID LEVEL WARM ADVECTION
CONTINUES IN EARNEST SUNDAY AFTERNOON LOW LEVEL CLOUDS WILL LIKELY
LINGER AS MID LEVEL SHORTWAVE TROUGH REMAINS OVER CENTRAL NORTH
DAKOTA. WILL KEEP SOME SLIGHT CHANCE POPS SOUTH CENTRAL SUNDAY
AFTERNOON. WITH THE INCREASE IN CLOUDS ALSO DROPPED HIGH
TEMPERATURES A BIT SUNDAY AFTERNOON FROM THE PREVIOUS FORECAST.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 213 PM CDT SAT MAY 30 2015

AN ACTIVE WEATHER PATTERN WILL CONTINUE TO BE THE MAIN HIGHLIGHT IN
THE LONG TERM PERIOD.

THE LONG TERM BEGINS SUNDAY NIGHT WITH ZONAL FLOW ALOFT AND WEAK
SHORTWAVE ENERGY MOVING EAST/SOUTHEAST ACROSS CENTRAL NORTH DAKOTA.
THE NAM...CANADIAN REGIONAL...AND SREF MODELS KEEP LIGHT RAIN OVER
SOUTH CENTRAL/SOUTHEAST NORTH DAKOTA DURING MAINLY THE EVENING
HOURS. THERE IS SUFFICIENT H850 SOUTHEAST WINDS OF 20 TO 30 KNOTS
WITH HIGH MOISTURE CONTENT MOVING NORTHWARD TO WARRANT THE SLIGHT
CHANCE MENTION OF RAIN SHOWERS SUNDAY EVENING.

SUNDAY NIGHT AND MONDAY A LARGE UPPER LEVEL LONGWAVE TROUGH OVER THE
WEST COAST/PACIFIC NORTHWEST DEVELOPS SOUTHWEST FLOW ALOFT OVER THE
ROCKIES AND INTO THE FRONT RANGE BY MONDAY AFTERNOON. THUNDERSTORM
DEVELOPMENT OVER MONTANA MOVING INTO WESTERN NORTH DAKOTA WILL KEEP
A CHANCE OF THUNDERSTORMS WEST DAYTIME MONDAY. LOW LEVEL JET SETS UP
MOVING NORTHWARD INTO NORTH DAKOTA WITH CAPE INCREASING DURING THE
AFTERNOON WEST. THERE IS A CHANCE THAT THUNDERSTORMS WEST COULD
MAINTAIN SEVERE LEVELS MONDAY AFTERNOON AS THEY MOVE INTO OR DEVELOP
OVER FAR WESTERN NORTH DAKOTA.

MONDAY NIGHT THE UPPER LEVEL RIDGE MOVES EAST ACROSS THE STATE AND
ALLOWS SOUTHWEST FLOW ALOFT TO BRING PLENTY OF UPPER LEVEL
SHORTWAVES NORTHEAST INTO THE NORTHERN PLAINS. INCREASING BULK SHEAR
AND CAPE SPREADING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE
SURFACE LOW REMAINS OVER MONTANA/WYOMING. SOME SEVERE STORMS MAY
MOVE INTO OR DEVELOP OVER WESTERN INTO CENTRAL NORTH DAKOTA...WITH
INCREASING CAPE AND BULK SHEAR. STORM PREDICTION CENTER HAS THE FAR
SOUTHWEST IN A SLIGHT RISK OF SEVERE STORMS WITH MARGINAL SEVERE FOR
THE WEST HALF OF THE STATE.

BY DAYBREAK ON TUESDAY MORNING THERE SHOULD BE ONGOING CONVECTION
FROM MONDAY NIGHT WITH A STRONG UPPER LEVEL SHORTWAVE MOVING
NORTHEAST ACROSS WESTERN NORTH DAKOTA. THE SURFACE LOW BECOMES MORE
BROAD OVER THE DAKOTAS DURING THE DAY WITH H850 TRANSPORT WELL NORTH
INTO CANADA AND A WARM FRONT MOVING NORTHWARD ACROSS NORTH DAKOTA
DURING THE DAY. DURING THE AFTERNOON THE SURFACE LOW IS PROGGED TO
BE OVER THE WESTERN DAKOTAS WITH DRY AIR MOVING IN BEHIND WESTERLY
WINDS OVER FAR SOUTHWESTERN NORTH DAKOTA. SURFACE BOUNDARIES MOVING
ACROSS THE STATE...INCREASING BULK SHEAR AND CAPE...ALL INGREDIENTS
WILL BE IN PLACE FOR WIDESPREAD THUNDERSTORMS TUESDAY. SEVERE
PARAMETERS ALSO IN PLACE. MOST UNSTABLE CAPE VALUES OF 1000-3500
J/KG AND BULK SHEAR VALUES IN THE 25-45 KNOT RANGE - AND STORM
PREDICTION CENTER HAS THE DAKOTAS IN A SLIGHT RISK FOR SEVERE STORMS
IN THE OUTLOOK FOR TUESDAY AND TUESDAY NIGHT. WILL SEE HOW THE NEXT
COUPLE OF MODEL RUNS LOOK - AND LATER SHIFTS MAY ADD SEVERE WORDING
TO THE FORECAST FOR TUESDAY.

THE REST OF THE WEEK THE MODELS KEEP AN UPPER LEVEL LOW/TROUGH
NEARLY PERSISTENT OVER THE WESTERN US...WITH SOUTHWEST UPPER LEVEL
FLOW OVER NORTH DAKOTA. THIS WILL KEEP THE MENTION OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST EACH DAY.

THE WARMEST DAY IN THE LONG TERM LOOKS TO BE MONDAY BEFORE THE BIG
CHANCES OF THUNDERSTORMS OCCUR. LOOKING FOR HIGHS FROM 75 TO 85
MONDAY...WITH MAINLY 70S THROUGH THE WEEK INTO NEXT WEEKEND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 624 PM CDT SAT MAY 30 2015

CIGS WILL LOWER LATE THIS EVENING OVER MANY LOCATIONS AS RAIN
SHOWERS APPROACH THE AREA. MVFR CIGS ARE EXPECTED OVER MOST
LOCATIONS BY LATE TONIGHT...WITH SHOWERS PRODUCING AREAS OF MVFR
VIS. LCL IFR VIS MAY BE POSSIBLE IN HEAVIER SHOWERS OVER PORTIONS
OF SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA. CIG LEVELS WILL
INCREASE BY LATE MORNING TO VFR OVER MOST LOCATIONS.


&&

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

$$

UPDATE...ZH
SHORT TERM...TWH
LONG TERM...JV
AVIATION...JJS


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