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000
FXUS63 KBIS 181151
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
651 AM CDT TUE JUN 18 2013

.UPDATE...
ISSUED AT 648 AM CDT TUE JUN 18 2013

NO SIGNIFICANT CHANGES FOR EARLY MORNING FORECAST UPDATE.
VISIBILITIES CONTINUE TO GO UP AND DOWN ACROSS PORTIONS OF WESTERN
AND CENTRAL NORTH DAKOTA. PATCHY DENSE FOG CONTINUES IN FORECAST
UNTIL 10 AM CDT...ALTHOUGH NOT WIDESPREAD OR PERSISTENT ENOUGH TO
WARRANT AN ADVISORY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT TUE JUN 18 2013

THE INITIAL CONCERN FOR TODAY IS FOG. EARLY MORNING SURFACE
ANALYSIS PLACES AN AXIS OF SURFACE HIGH PRESSURE ACROSS CENTRAL
NORTH DAKOTA. THIS HAS BROUGHT LIGHT WINDS...WHICH COMBINED WITH
CLEAR SKIES AND LOW DEWPOINT DEPRESSIONS HAS ALLOWED PATCHY FOG TO
DEVELOP. WILL ADD FOG TO THE CENTRAL AND EAST...WHICH ARE IN THE
HEART OF THE SURFACE HIGH. ONCE THE FOG LIFTS...A MOSTLY SUNNY DAY
SHOULD BE IN STORE FOR MUCH OF THE FORECAST AREA. FOLLOWED A BLEND
OF GUIDANCE VALUES FOR HIGHS TODAY WITH MID 70S TO NEAR 80
EXPECTED IN MOST LOCATIONS.

ATTENTION TONIGHT SHIFTS TO THE POSSIBILITY OF CONVECTION IN PARTS
SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA. A WAVE WILL RIDE AN H5
RIDGE INTO PARTS OF SOUTH DAKOTA TONIGHT. THIS WILL BRING
THUNDERSTORMS TO WESTERN SOUTH DAKOTA...WHICH COULD SPREAD INTO
SOUTHERN PARTS OF THE FORECAST AREA LATER THIS EVENING / TONIGHT.
WILL MAINTAIN SLIGHT CHANCE POPS FOR NOW SINCE CONFIDENCE IN
THUNDERSTORMS REACHING THE FORECAST AREA IS NOT HIGH. LOWS TONIGHT
SHOULD BE IN THE MID 50S TO NEAR 60.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 356 AM CDT TUE JUN 18 2013

THE MAIN FORECAST ISSUE THROUGH THE LONG TERM PERIOD IS CONVECTIVE
TRENDS AND POTENTIAL FOR PERIODS OF STRONG TO SEVERE STORMS...SOME
ACCOMPANIED BY HEAVY RAINFALL.

THE 18/00Z OPERATIONAL RUNS OF THE GFS/ECMWF ARE IN GENERAL
AGREEMENT WITH A SLOWER PROGRESSION OF A LARGE CLOSED UPPER LOW IN
THE PACIFIC NORTHWEST EARLY IN THE PERIOD. HAVE FAVORED THESE
SOLUTIONS FOR POPS WEDNESDAY NIGHT AND THURSDAY. THERE IS SOME
POTENTIAL FOR AN MCS TO CLIP NORTHWEST COUNTIES LATE WEDNESDAY
NIGHT INTO THURSDAY MORNING...FUELED BY A 40+ KT LOW LEVEL JET AND
PWAT VALUES AOA 1.5 INCHES. STRONG TO SEVERE STORMS ARE ALSO
FAVORED ACROSS THE NORTHERN HALF OF THE FORECAST AREA THURSDAY
AFTERNOON AND NIGHT. ADDITIONAL SHORT WAVE ENERGY WILL STREAM INTO
THE NORTHERN PLAINS IN PERSISTENT SOUTHWEST FLOW FRIDAY THROUGH
SATURDAY...PROVIDING ADDITIONAL CHANCES FOR SEVERE STORMS AND
LOCALLY HEAVY RAINFALL. HPC DAY 1 TO 7 QPF INDICATES POTENTIAL FOR
WIDESPREAD AMOUNTS AROUND 2 INCHES...ESPECIALLY NORTH ACROSS THE
SOURIS BASIN WHERE FLOODING ISSUES CONTINUE. TEMPERATURES ARE
EXPECTED TO BE NEAR OR SLIGHTLY ABOVE SEASONAL NORMS THROUGH THE
PERIOD...WITH HIGHS IN THE UPPER 70S/LOWER 80S...AND LOWS
GENERALLY IN THE UPPER 50S/LOW 60S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 648 AM CDT TUE JUN 18 2013

PATCHY DENSE FOG HAS DEVELOPED ACROSS PARTS OF CENTRAL
AND WESTERN NORTH DAKOTA EARLY THIS MORNING.  VISIBILITIES HAVE
FLUCTUATED RAPIDLY DUE TO THE SHALLOW DENSE NATURE OF THE FOG.  WILL
CARRY A BRIEF TEMPO GROUP AT KBIS/KJMS/KISN FOR REDUCED VISIBILITIES
SINCE FOG HAS ALREADY BEEN REPORTED AT THOSE LOCATIONS. THE FOG
SHOULD LIFT QUICKLY THIS MORNING LEAVING VFR CONDITIONS IN PLACE
FOR THE REMAINDER OF THE TAF PERIOD. THERE COULD BE AN ISOLATED
THUNDERSTORM AT KDIK OR KBIS LATER TONIGHT...BUT CHANCES APPEAR
SMALL ENOUGH TO OMIT FROM THE FORECAST FOR NOW.

&&

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

$$

UPDATE/LONG TERM...RP KINNEY
AVIATION...CK