Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 271435
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
935 AM CDT SAT JUN 27 2015

.UPDATE...
ISSUED AT 935 AM CDT SAT JUN 27 2015

A FEW THUNDERSTORMS IN ROLETTE COUNTY HAVE EXITED THAT AREA OVER
THE LAST HOUR. BASED ON CURRENT RADAR...SATELLITE AND SHORT RANGE
MODELS...REMOVED LOW POPS FOR THE NEXT FEW HOURS. OTHERWISE...WEAK
FRONT HAS MOVED THROUGH WILLISTON AS OF 14Z. 12Z NAM IS COMING IN
NOW AND APPEARS TO BE CONSISTENT WITH PREVIOUS RUN. MAIN ISSUE
TODAY WILL BE THUNDERSTORM COVERAGE AND POSSIBILITY OF SEVERE.
HIGH RES MODELS CONTINUE TO SHOW INITIATION OF ISOLATED/SCATTERED
STORMS AFTER 18Z. NAM/GFS KEEP BEST COVERAGE ON CYCLONIC SHEAR
SIDE OF 110KT JET STREAK...MAINLY TO OUR EAST...THAT IS NOSING
INTO NORTH CENTRAL ND AT THIS TIME. HOWEVER THERE IS STILL 1000+
J/KG CAPE AHEAD OF THE FRONT...MAINLY ACROSS OUR SOUTHEASTERN AREA
THIS AFTERNOON. WILL CONTINUE TO CARRY ISOLATED/SCATTERED COVERAGE
FOR THIS AFTERNOON AND EARLY EVENING. SPC HAS CONTINUED TO KEEP
THE JAMES RIVER VALLEY IN SLIGHT CHANCE FOR SEVERE THIS
AFTERNOON.

UPDATE ISSUED AT 649 AM CDT SAT JUN 27 2015

REGIONAL RADAR MOSAIC SHOWS MUCH OF THE SHOWER / THUNDERSTORM
ACTIVITY HAS DIMINISHED EARLY THIS MORNING. THE LATEST HRRR AND
RAP 13 STILL SUGGEST AN ISOLATED SHOWER OR STORM IS POSSIBLE THIS
MORNING IN THE CENTRAL AND EAST....SO WILL KEEP A SMALL CHANCE IN
THE FORECAST. DID NOT CHANGE MUCH FOR THIS AFTERNOON WITH HIGH
RESOLUTION MODELS CONTINUING TO FOCUS THE THUNDERSTORM CHANCES
TOWARDS THE JAMES RIVER VALLEY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 259 AM CDT SAT JUN 27 2015

MAIN CONCERN IS THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS
AFTERNOON/EARLY EVENING OVER EAST CENTRAL NORTH DAKOTA...FROM THE
TURTLE MOUNTAINS SOUTH INTO THE JAMES RIVER VALLEY.

THE LATEST WATER VAPOR IMAGERY SHOWS NORTHWESTERLY FLOW INTO
NORTH DAKOTA WITH A MID LEVEL SHORTWAVE PUSHING THROUGH NORTHWEST
AND NORTH CENTRAL NORTH DAKOTA. LOCAL RADAR SHOWS ISOLATED SHOWERS
DWINDLING...HOWEVER AN AREA OF THUNDERSTORMS OVER SOUTHEAST
SASKATCHEWAN AND SOUTHWEST MANITOBA...WERE MOVING TOWARD THE
TURTLE MOUNTAINS BUT SHOWING SIGNS OF WEAKENING. FARTHER
UPSTREAM...A STRONGER MID LEVEL SHORTWAVE WITH AN 80KT JET STREAK
OVER CENTRAL SASKATCHEWAN WAS ALSO MOVING SOUTHEAST WITH TIME. AT
THE SURFACE...3HR PRESSURE FALLS WERE MAXIMIZED OVER SOUTHERN
SASKATCHEWAN/MANITOBA...AHEAD OF AN ADVANCING COLD FRONT IN
CENTRAL SASKATCHEWAN AND NORTH CENTRAL MONTANA.

TIMING AND PLACEMENT OF THE COLD FRONT WILL DETERMINE THE
COVERAGE AND INTENSITY OF SEVERE WEATHER POTENTIAL. THE HIGH
RESOLUTION MODELS SUGGEST THE GREATEST RISK FOR SEVERE WEATHER
RESIDES IN THE JAMES RIVER VALLEY...WITH MORE UNCERTAINTY NORTH IN
THE TURTLE MOUNTAINS. THE GLOBAL MODELS KEEP THE BEST DYNAMICS
EAST...WHERE THE SHORTWAVE AND JET STREAK WILL INTERACT WITH
HIGHER INSTABILITY THIS AFTERNOON. THIS IS IN LINE WITH THE SLIGHT
RISK PER SPC CONVECTIVE OUTLOOK. HOWEVER CAPE VALUES RANGING
BETWEEN 1500-2000 J/KG AND 0-6KM BULK SHEAR OF 45KT TO 55KT ARE
FORECAST ACROSS THE JAMES RIVER VALLEY BY MID TO LATE
AFTERNOON...NEAR OR JUST PRIOR TO FRONTAL PASSAGE. THE CAPE/SHEAR
VALUES DECREASE NORTH INTO THE TURTLE MOUNTAINS...BUT STILL MAY
POSE A THREAT...ALBEIT A LESSER THREAT AS MENTIONED ABOVE. LATEST
SPC CONVECTIVE OUTLOOK HAS A SHARP GRADIENT BETWEEN
GENERAL/MARGINAL/SLIGHT RISK OVER EAST CENTRAL NORTH DAKOTA
TODAY...WHICH COULD CHANGE LATER THIS MORNING AS NEWER DATA
BECOMES AVAILABLE. FOR NOW...HAVE INJECTED SEVERE THUNDERSTORM
WORDING INTO THE FORECAST PRODUCTS FROM NEAR THE TURTLE MOUNTAINS
SOUTH INTO THE JAMES RIVER VALLEY. OTHERWISE NORTHWEST FLOW WITH
EMBEDDED SHORTWAVES AHEAD OF THE MAIN FEATURE THIS AFTERNOON WILL
LIKELY RENEW ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE
MORNING HOURS IN CENTRAL NORTH DAKOTA. HAVE INCLUDED THIS IN THE
MORNING FORECAST. NORTHWEST WINDS 15KT TO 25KT WILL DEVELOP BEHIND
THE COLD FRONT THIS AFTERNOON WEST AND CENTRAL. DRY CONDITIONS
WEST TODAY. H85 TEMPS WARM BY ANOTHER 3C TO 4C WHICH YIELDS
AFTERNOON HIGHS IN THE UPPER 80S TO AROUND 90.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 259 AM CDT SAT JUN 27 2015

DRY WEATHER IS EXPECTED TO START THE LONG TERM PERIOD...THOUGH
CAN`T COMPLETELY RULE OUT A ROGUE SHOWER OR THUNDERSTORM SUNDAY
NIGHT AS PER THE GFS. BY MONDAY NIGHT...WEST / NORTHWEST FLOW WILL
BE IN PLACE ALOFT WITH PERIODIC WAVES MOVING ACROSS THE NORTHERN
PLAINS. WILL GENERALLY FOLLOW A MODEL BLEND WHICH KEEPS A CHANCE
OF THUNDERSTORMS MUCH OF NEXT WEEK.

TEMPERATURES WILL START OUT ON THE WARM SIDE OF AVERAGE...WITH
MONDAY APPEARING TO BE THE WARMEST DAY OF THE PERIOD. THE REST OF
THE WEEK SHOULD BE RELATIVELY SEASONABLE WITH HIGHS IN THE MID 70S
TO LOWER 80S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 649 AM CDT SAT JUN 27 2015

A COLD FRONT WILL MOVE  ACROSS WESTERN AND CENTRAL NORTH DAKOTA
SATURDAY...WITH WINDS SHIFTING TO THE NORTHWEST BETWEEN 15KT AND
25KT. THE HIGHEST THREAT FOR A THUNDERSTORM SATURDAY AFTERNOON
RESIDES AT KJMS FROM 21Z SATURDAY THROUGH 00Z SUNDAY. HAVE A VCTS
MENTION AT KJMS UNTIL SOMETHING MORE DEFINITIVE DEVELOPS. ALSO HAVE
INTRODUCED A VCTS AT KBIS BETWEEN 17Z AND 22Z SATURDAY...JUST PRIOR
TO THE COLD FRONTAL PASSAGE.


&&

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

$$

UPDATE...JNS
SHORT TERM...KS
LONG TERM...CK
AVIATION...KS


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