Area Forecast Discussion
Issued by NWS Bismarck, ND

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000
FXUS63 KBIS 011455
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
955 AM CDT FRI AUG 1 2014

.UPDATE...

ISSUED AT 955 AM CDT FRI AUG 1 2014

SURFACE LOW PRESSURE CENTERED NEAR SOUTHWEST NORTH DAKOTA...WITH
A FRONTAL BOUNDARY STRETCHED FROM WESTERN SOUTH DAKOTA BACK
NORTHWEST ACROSS EASTERN MONTANA. NORTHWEST FLOW ALOFT WITH A MID
LEVEL S/WV IMPULSE MOVING SLOWLY SOUTHEAST ACROSS EASTERN MONTANA
IS INTERACTING WITH THIS BOUNDARY TO TRIGGER A FEW
SHOWERS/ISOLATED THUNDERSTORMS OVER MY FAR WESTERN COUNTIES.

ADDITIONAL MID LEVEL IMPULSES WILL PUSH THROUGH ALOFT
TODAY/TONIGHT. WITH THE FRONTAL BOUNDARY REMAINING QUASI-
STATIONARY...WILL CONTINUE TO MENTION A CHANCE OF
PRECIPITATION...WEST AND SOUTH THIS EVENING...NORTH OVERNIGHT.
WHILE WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...WILL HAVE
ENOUGH INSTABILITY AND SUFFICIENT 0-6KM SHEAR FOR THE POSSIBILITY
OF A FEW ORGANIZED UPDRAFTS AND THUS A SMALL THREAT FOR LARGE
HAIL. ALSO...CIGS AT AROUND 8-10K FEET AGL WILL ELEVATE THE CHANCE
FOR A FEW STRONGER WIND GUSTS WITH ANY STORMS.


UPDATE ISSUED AT 643 AM CDT FRI AUG 1 2014

NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE OTHER THAN TO
BLEND TO THE 1130 UTC OBSERVED TRENDS AS THE INHERITED FORECAST IS
IN LINE WITH THE 06 UTC GFS/NAM AND 08-09 UTC HRRR ITERATIONS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CDT FRI AUG 1 2014

CURRENTLY...A SURFACE LOW WAS OVER EASTERN MONTANA WHILE BROAD HIGH
PRESSURE STRETCHES FROM MANITOBA THROUGH THE EASTERN DAKOTAS INTO
THE MINNESOTA. AT UPPER LEVELS A RIDGE EXTENDED FROM THE GREAT BASIN
INTO THE NORTHERN ROCKIES WHILE AN UPPER LEVEL LOW SPINS NEAR JAMES
BAY BRINGING NORTH-NORTHWESTERLY FLOW TO OUR AREA WITH A VARIETY OF
WEAK IMPULSES SLIDING THROUGH.

A SMALL CLUSTER OF THUNDERSTORMS OVER SOUTH CENTRAL SASKATCHEWAN...IN
THE SWIFT CURRENT AREA...CONTINUED TO SUSTAIN ITS CONVECTION THROUGH
THE EARLY MORNING HOURS. THE MODELS DEPICT A WEAK UPPER LEVEL
IMPULSE IN THE AREA WHERE CURRENT THUNDERSTORM ACTIVITY WAS
OCCURRING. THE NAM DEPICTS THE WEAK UPPER LEVEL IMPULSE MOVING
SOUTHEASTWARD SLOWLY...APPROACHING NORTHWESTERN NORTH DAKOTA
BEFORE/AROUND DAYBREAK...THEN MOVING THROUGH SOUTHWESTERN NORTH
DAKOTA FRIDAY AFTERNOON.

LATER TODAY...THE MODELS INDICATE THE EASTERN MONTANA SURFACE LOW
DEVELOPS SOUTHWARD AND AN EAST-WEST SURFACE FRONTAL BOUNDARY BECOMES
ESTABLISHED OVER NORTHERN SOUTH DAKOTA. THIS SURFACE BOUNDARY
COMBINED WITH WEAK UPPER LEVEL IMPULSES MOVING THROUGH THE
NORTHWESTERLY FLOW ALOFT SHOULD RESULT IN BETTER CHANCES OF
CONVECTION IN SOUTH DAKOTA...THUS WILL KEEP THE MENTION OF SLIGHT
CHANCE OF THUNDERSTORMS ACROSS THE SOUTH.

FRIDAY NIGHT...THE UPPER LEVEL IMPULSE AND ASSOCIATED SURFACE
BOUNDARY IN SOUTH DAKOTA MOVES FARTHER SOUTH. ATTENTION THEN TURNS
TO THE NEXT UPPER LEVEL IMPULSE MOVING SOUTHEASTWARD OUT OF
SASKATCHEWAN. THIS FEATURE APPROACHES NORTHWESTERN NORTH DAKOTA
FRIDAY EVENING...AND IS PROGGED TO REACH THE CENTRAL DAKOTAS AFTER
MIDNIGHT. WILL KEEP SLIGHT CHANCES OF THUNDERSTORMS NORTHWEST THIS
EVENING...WITH ISOLATED TO SCATTERED CHANCES LATE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 333 AM CDT FRI AUG 1 2014

A MORE ACTIVE WEATHER PATTERN WILL HIGHLIGHT THE EXTENDED FORECAST.

THE 00 UTC DETERMINISTIC AND ENSEMBLE SUITES ARE IN GOOD AGREEMENT
ON AN UPPER LEVEL RIDGE CENTERED ACROSS THE INTERMOUNTAIN WEST
THIS WEEKEND...SLOWLY BREAKING DOWN WITH A TRANSITION TO NEAR
ZONAL FLOW EARLY NEXT WEEK. THIS SUPPORTS DAILY CHANCES FOR
THUNDERSTORMS ASSOCIATED WITH IMPULSES PROPAGATING ALONG THE
NORTHERN PERIPHERY OF THE RIDGE AND EMBEDDED WITHIN THE ZONAL
FLOW. CERTAINLY CANNOT RULE OUT AN ISOLATED SEVERE THREAT EACH DAY
SUNDAY THROUGH WEDNESDAY...HOWEVER...A WIDESPREAD SEVERE THREAT
IS NOT EXPECTED AT THIS TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI AUG 1 2014

A SMALL CLUSTER OF THUNDERSTORMS THAT ENTERED NORTHEASTERN MONTANA
FROM SASKATCHEWAN WILL CONTINUE TO MOVE TOWARDS KISN. STORMS COULD
DIMINISH GREATLY AFTER 13Z-15Z. OTHERWISE VFR CONDITIONS EXPECTED
THROUGH THE FORECAST PERIOD. ADDITIONAL ISOLATED STORMS ARE
FORECAST LATE THIS AFTERNOON AND EVENING ACROSS WESTERN AND SOUTH
CENTRAL NORTH DAKOTA. HOWEVER...GIVEN LOW COVERAGE...DIRECT IMPACTS
TO ANY ONE TERMINAL ARE UNLIKELY.


&&

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

$$

UPDATE...NH
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD





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