Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 040559
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1259 AM CDT SAT JUL 4 2015

.UPDATE...
ISSUED AT 1249 AM CDT SAT JUL 4 2015

SMOKE STILL REDUCING VISIBILITIES...WITH BETTER VISIBILITIES WEST
AND LOWER VISIBILITIES EAST. LOW LEVEL SOUTHERLY JET IS FORECAST TO
DEVELOP THIS MORNING AND CONTINUE STRENGTHENING DURING THE DAYTIME
HOURS ON SATURDAY. THIS SHOULD IMPROVE VISIBILITIES GREATLY ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.

LATEST SHORT TERM HIGH RES MODELS CONTINUE TO DEPICT ISOLATED
SHOWERS/THUNDER OVER SOUTH CENTRAL NORTH DAKOTA EARLY THIS MORNING.
HOWEVER...NOTHING YET DETECTED ON SATELLITE OR RADARS. LATEST
MESOSCALE ANALYSIS FROM SPC PAGE INDICATES SUFFICIENT CAPE AND SHEAR
TO SUPPORT CONVECTION...AND WEAK UPPER LEVEL SHORTWAVE CONTINUES TO
DRIFT EASTWARD ACROSS SOUTH CENTRAL ND AND NORTH CENTRAL SD. THUS
KEPT THE SLIGHT CHANCE MENTION FOR THE OVERNIGHT HOURS.

CURRENT FORECAST ON TRACK.

UPDATE ISSUED AT 910 PM CDT FRI JUL 3 2015

ADDED SMOKE TO THE SOUTHWEST WHERE 9 PM CDT OBSERVATIONS FROM
DICKINSON AND HETTINGER HAVE 5 MILES VISIBILITY IN SMOKE AND HAZE.
APPEARS THE CONVECTION HAS DIED OUT ACROSS THE WEST SO WILL END
THE THREAT FOR THUNDERSTORMS FOR THE REMAINDER OF THE EVENING.

UPDATE ISSUED AT 621 PM CDT FRI JUL 3 2015

ONE OR TWO STRONG THUNDERSTORMS ARE EXPECTED TO CONTINUE FOR A FEW
HOURS THIS  EVENING WEST CENTRAL. CURRENTLY THERE IS LITTLE SHEAR
ALTHOUGH THESE STORMS HAVE SUPERCELL CHARACTERISTICS. POTENTIAL
FOR LARGE HAIL WILL BE PRESENT FOR AN HOUR OR TWO THIS EVENING.
RAISED POPS WEST CENTRAL.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 236 PM CDT FRI JUL 3 2015

MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE ISOLATED
THUNDERSTORM CHANCES AND REDUCTIONS IN VISIBILITY DUE TO SMOKE.

LATEST SATELLITE IMAGERY SHOWS WEAK SHORTWAVES EMBEDDED IN
NORTHWEST FLOW OVER EASTERN NORTH DAKOTA/MINNESOTA AND DROPPING
THROUGH WESTERN SOUTH DAKOTA. ANOTHER WAVE WAS NOTED MOVING ACROSS
NORTHWEST MONTANA.

ACROSS WESTERN AND CENTRAL NORTH DAKOTA. AFTERNOON CUMULUS
FORMATION WITH LITTLE IN THE WAY OF VERTICAL EXTENT AT THIS TIME.
THERE WERE A COUPLE SHOWERS NOTED DURING THE PAST HOUR OVER THE
SOUTHWEST...BUT THESE HAVE SINCE DISSIPATED. DID KEEP A MENTION OF
A SHOWER OR THUNDERSTORMS FOR CONSISTENCY SAKE THIS AFTERNOON
THROUGH TONIGHT. THIS AFTERNOON/EVENING WOULD BE SOLELY DUE TO
AFTERNOON HEATING WITH 1000-3000 J/KG OF CAPE...BUT NO SHEAR AND
WEAK LAPSE RATES. ANYTHING THAT MIGHT DEVELOP WOULD BE SHORT LIVED
AND NOT EXPECTED TO BE SEVERE.

TONIGHT THE AFOREMENTIONED MONTANA SHORTWAVE MOVES INTO WESTERN
NORTH DAKOTA. THIS...COMBINED WITH AN INCREASING LOW LEVEL JET
WILL RESULT IN INCREASING INSTABILITY ALOFT. THUS AN ELEVATED
THUNDERSTORM CAN NOT BE RULED OUT. HAVE TAPERED DOWN THE AREA OF
SLIGHT CHANCE SHOWERS AND THUNDERSTORMS BOTH LATE THIS
AFTERNOON/THIS EVENING AND OVERNIGHT. KEEPING THIS
AFTERNOON/EVENING CHANCES WEST OF THE HIGHWAY 83 CORRIDOR...AND
OVERNIGHT CHANCES CONFINED TO THE SOUTHWEST AND SOUTH CENTRAL. DID
KEEP A MENTION OF SMOKE FOR MOST AREAS TONIGHT WITH WEAK SURFACE
AND UPPER LEVEL FLOW OVER THE AREA TONIGHT...DO NOT SEE ANY BIG
IMPROVEMENTS.

ON INDEPENDENCE DAY...A COLD FRONT WILL MOVE INTO NORTHWEST NORTH
DAKOTA BY LATE AFTERNOON. AHEAD OF THIS...THE ATMOSPHERE WILL
BECOME INCREASINGLY UNSTABLE WITH INCREASING SHEAR AHEAD OF THE
FRONTAL BOUNDARY MU CAPES OF 2000-3000 J/KG WITH SHEAR INCREASING
TO 20-30 KNOTS WOULD BE SUFFICIENT TO SUSTAIN ISOLATED STRONG TO
SEVERE THUNDERSTORMS. WILL NEED TO MONITOR AS WE MOVE INTO THE DAY
ON SATURDAY...BUT NO SEVER WORDING YET.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 236 PM CDT FRI JUL 3 2015

SATURDAY NIGHT THE COLD FRONT MENTIONED IN THE SHORT TERM
DISCUSSION WILL LIKELY BE DRAPED ACROSS CENTRAL NORTH DAKOTA. THE
GFS/ECMWF/NAM/SREF ARE ALL IN GOOD AGREEMENT ON THE TIMING AND
LOCATION OF THE FRONTAL PASSAGE. A FEW THUNDERSTORMS ARE POSSIBLE
AHEAD OF THE FRONT IN THE JAMES VALLEY...HOWEVER THE BULK OF THE
PRECIPITATION IS EXPECTED ALONG AND BEHIND THE FRONT.

THE COLD FRONT IS EXPECTED TO STALL ACROSS SOUTHERN NORTH DAKOTA
SUNDAY MORNING AS A SECONDARY SURFACE LOW IS FORECAST TO DEVELOP
ACROSS SOUTHEASTERN MONTANA. THIS SURFACE LOW WILL PROPAGATE
EASTWARD THROUGH THE DAY SUNDAY...SPAWNING SHOWERS AND
THUNDERSTORMS ACROSS MAINLY SOUTHERN NORTH DAKOTA. AFTER THIS
SYSTEM MOVES OUT SUNDAY EVENING...SURFACE HIGH PRESSURE IS
EXPECTED TO BUILD IN AND KEEP THE WEATHER RATHER QUIET UNTIL
MIDWEEK. TEMPERATURES WILL FALL BEHIND THE FRONT AND REMAIN BELOW
NORMAL...WITH READINGS IN THE 70S FOR HIGHS AND 40S/50S FOR
LOWS...THROUGH MIDWEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1249 AM CDT SAT JUL 4 2015

SURFACE HIGH PRESSURE OVER THE GREAT LAKES AREA WITH LOW PRESSURE
IN THE LEE OF THE ROCKIES HAS KEPT A WEAK SOUTHEASTERLY WIND FLOW
ACROSS TAF SITES AT 05Z. SMOKE CONTINUES TO REDUCE VISIBILITIES
TO MVFR AND IFR CATEGORIES. ASOS CIG INDICATOR DETECTING SMOKE AS A
CLOUD LAYER IN SOME AREAS. THE RADIATION INVERSION SETTING UP SHOULD
KEEP THESE CONDITIONS PERSISTENT FOR THE EARLY MORNING HOURS.
HOWEVER...AS THE LOW LEVEL INVERSION BREAKS LATER TODAY...AROUND
16Z...EXPECTING VSBYS TO IMPROVE TO VFR ALL TAF SITES. ATTENTION
THEN TURNS TO COLD FRONT APPROACHING NORTHWESTERN NORTH DAKOTA THIS
AFTERNOON. HAVE MENTION OF VCTS AT KISN AND KMOT LATE AFTERNOON AND
EVENING.

&&

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

$$

UPDATE...JV
SHORT TERM...TWH
LONG TERM...AJ
AVIATION...JV



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