000
FXUS63 KBIS 181756
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
1256 PM CDT TUE JUN 18 2013

.UPDATE...
ISSUED AT 1245 PM CDT TUE JUN 18 2013

A WEAK FEATURE ALOFT IS GENERATING SOME RADAR RETURNS IN EAST
CENTRAL MONTANA. MAY OR MAY NOT YET BE REACHING THE GROUND...BUT
HAVE ADDED SOME SPRINKLES TO WEST CENTRAL NORTH DAKOTA FRO THE
AFTERNOON. OTHERWISE...CURRENT FORECAST TODAY TRACKING ON
SCHEDULE.

UPDATE ISSUED AT 932 AM CDT TUE JUN 18 2013

WILL END THE MENTION OF PATCHY FOG FOR THIS UPDATE AS SATELLITE
LOOPS SHOW IT IS RAPIDLY BURNING OFF. MOSTLY SUNNY TODAY WITH
HIGHS CLOSE TO 80 SOUTHWEST AND MID 70S NORTH.

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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1245 PM CDT TUE JUN 18 2013

A SURFACE TROUGH IN EASTERN MONTANA WITH AN ASSOCIATED WARM FRONT
WILL BE THE FOCUS FOR INCREASING CHANCES FOR THUNDERSTORMS OVER
WEST AND CENTRAL NORTH DAKOTA TONIGHT AND WEDNESDAY. INITIALLY
THE THUNDERSTORMS WILL BE WIDELY SCATTERED ACROSS SOUTHWEST NORTH
DAKOTA AFTER 00Z. BECAUSE OF THIS HAVE NOT INCLUDED IN THE KDIK TAF.
ON WEDNESDAY...SOUTHERLY WINDS WITH THE APPROACHING WARM FRONT
SEEN IN THE SURFACE WIND FORECAST FOR KDIK-KISN-KBIS WITH
INCREASING SOUTHEAST WINDS TO 25 KTS AFTER 14Z. MAIN THREAT OF
THUNDERSTORMS AFTER 18Z SO DID NOT INCLUDE IN TAF FORECASTS...BUT
FOR AVIATION PLANNING MORE NUMEROUS STORMS WEDNESDAY AFTERNOON AND
NIGHT.

&&

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

$$

UPDATE...WAA
AVIATION...WAA