000
FXUS63 KBIS 120202
AFDBIS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
902 PM CDT TUE JUN 11 2013

.UPDATE...
ISSUED AT 855 PM CDT TUE JUN 11 2013

MAIN CONCERNS CONTINUE TO BE THUNDERSTORM THREAT. FINALLY GETTING
SOME CONVECTION GOING ACROSS THE SOUTHWEST. LOOKS AS THOUGH THIS
WILL CONTINUE TO EXPAND THROUGH TH EARLY MORNING. RAISED POPS
WEST CENTRAL THROUGH SOUTHWEST FOR THE EVENING INTO THE EARLY
MORNING. OTHERWISE...CONTINUE TO MONITOR FOR SEVER STORMS. MID
LEVEL LAPSE RATES NOT VERY IMPRESSIVE NORTH OF SOUTH DAKOTA. STILL
LOOKING FOR SEVERE POTENTIAL MAINLY FAR SOUTHWEST.

UPDATE ISSUED AT 638 PM CDT TUE JUN 11 2013

MAIN CONCERNS FOR THIS UPDATE INCLUDE TIMING OF PRECIPITATION AND
THE POSSIBILITY OF SEVERE STORMS. AT THIS TIME...FOLLOWING THE
SATELLITE TRENDS...LIFT OVER THE FRONTAL BOUNDARY ACROSS SOUTH
DAKOTA IS GENERATING CLOUDS ACROSS SOUTHWEST AND SOUTH CENTRAL
NORTH DAKOTA. THERE IS LITTLE INSTABILITY THERE YET. SKIES ARE
MAINLY CLEAR OVER MUCH OF CENTRAL NORTH DAKOTA.

DELAYED THE ONSET OF THUNDERSTORMS A FEW HOURS...ESPECIALLY WEST
AND SOUTH CENTRAL...TO LET THE THERMODYNAMICS CATCH UP. STILL
THINK THERE WILL BE THE POTENTIAL FOR A SEVERE STORM OR TWO FAR
SOUTHWEST. TEMPERATURES AND WINDS LOOK OK TONIGHT. CLOUDS WILL FILL
IN ACROSS CENTRAL NORTH DAKOTA LATER THIS EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 343 CDT TUE JUN 11 2013

THE MAIN FORECAST CHALLENGE FOR THE PERIOD WILL BE CHANCES FOR
SEVERE THUNDERSTORMS THIS EVENING AND TONIGHT.

FOR THIS AFTERNOON...MOSTLY DRY CONDITIONS ARE EXPECTED AREAWIDE.
AN UPPER LEVEL JET STREAK COMBINED WITH MID-LEVEL INSTABILITY IS
GENERATING A LINE OF ALTO-CU EXTENDING FROM HETTINGER TO NEAR
LINTON TO JAMESTOWN. DO NOT EXPECT MUCH...IF ANY...PRECIP AS THE
LOW-LEVELS ARE RELATIVELY DRY. AREAS SOUTH OF I-94 WILL LIKELY
MAINLY SEE VIRGA.

FOR THIS EVENING...MIXED LAYER MUCAPE IS PROGGED TO INCREASE TO UP
TO 400 J/KG ACROSS SOUTHWESTERN NORTH DAKOTA AFTER 00Z. DEEP LAYER
(0-6KM) WIND SHEAR IS PROGGED TO BE AROUND 35 KNOTS AT THE SAME
TIME. FURTHERMORE...AN UPPER LEVEL SHORTWAVE IS FORECAST TO LIFT
INTO NORTHEASTERN WYOMING/SOUTHEASTERN MONTANA. THE COMBINATION OF
INSTABILITY...SHEAR...AND LIFT MAY PRODUCE A SEVERE THUNDERSTORM OR
TWO ACROSS EXTREME SOUTHWESTERN NORTH DAKOTA THIS EVENING. LARGE
HAIL AND DAMAGING WINDS ARE THE PRIMARY THREATS. WILL HIGHLIGHT
THESE THREATS IN THE HWO.

THE CONVECTIVE ACTIVITY SHOULD DIMINISH AFTER MIDNIGHT TONIGHT AS
THE INSTABILITY AND SHEAR AXES SHIFT FARTHER INTO SOUTH DAKOTA.

FOR WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO DIMINISH THROUGH THE
MORNING HOURS. DRY CONDITIONS ARE EXPECTED AREAWIDE BY THE AFTERNOON
AS UPPER LEVEL RIDGING BUILDS ACROSS THE NORTHERN PLAINS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 343 CDT TUE JUN 11 2013

FOCUS IN THE LONG TERM WILL BE ON THE CHANCE FOR THUNDERSTORMS
FRIDAY.

MODELS ARE STILL IN GOOD AGREEMENT ON SOUTHWESTERLY FLOW ALOFT
SETTING UP OVER CENTRAL AND WESTERN NORTH DAKOTA BY 00 UTC FRIDAY AS
AN RIDGE BEGINS TO PROPAGATE EAST. A BIT OF UNCERTAINTY DOES REMAIN
AT THE SURFACE AS THE 12 UTC GUIDANCE SUITE DIFFERS ON HOW FAR EAST
THE SURFACE COLD FRONT WILL ADVANCE THROUGH THE AFTERNOON. THE 12
UTC ECMWF AND 15 UTC SREF NEARLY CLEAR THE CWA BY 00 UTC WITH THE 12
UTC GFS/GEM LAGGING THE FRONT ACROSS CENTRAL NORTH DAKOTA. THIS
DIFFERENCE IN FRONTAL POSITION HAS A SIGNIFICANT IMPACT AS TO WHERE
CONVECTION WILL BE FOCUSED BY PEAK AFTERNOON AND EARLY EVENING
HEATING ON FRIDAY...AS INSTABILITY AND SHEAR PROFILES SUPPORT
POSSIBLE SEVERE CONVECTION. THAT BEING SAID WITH AMPLE MOIST
SOUTHERLY FLOW AHEAD OF THE FRONT AT THE SURFACE AND A MODERATELY
STRONG UPPER LEVEL SOUTHWESTERLY JET...DO EXPECT SHOWERS AND
THUNDERSTORMS TO FORM ALONG THE FRONT AS IT PUSHES EAST ACROSS THE
STATE. THIS SYSTEM WILL HAVE TO CONTINUED TO BE WATCHED THROUGH THE
WEEK TO SEE IF THE TIMING IS EITHER SPED UP OR DELAYED.

OTHERWISE FOR THE LONG TERM...MODELS ARE IN GOOD AGREEMENT ON
CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY ACROSS WESTERN NORTH
DAKOTA AND A DRY SATURDAY. WITH RESPECT TO HYDRO...ACCUMULATIONS
FROM THESE CHANCES FOR RAIN FROM BOTH THE 12 UTC GFS AND ECMWF RANGE
FROM A TENTH OF AN INCH TO THREE QUARTERS OF AN INCH THROUGH THE
WEEKEND. EVEN WITH THE SATURATED SOILS ACROSS CENTRAL AND WESTERN
NORTH DAKOTA THIS SHOULD NOT PRESENT ANY FURTHER FLOODING PROBLEMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 855 PM CDT TUE JUN 11 2013

THE MAIN HAZARD TO AVIATION WILL BE THUNDERSTORMS ACROSS THE WEST
AND SOUTH TONIGHT AND WEDNESDAY MORNING. AT 9 PM CDT...THE MAIN
WEATHER FEATURES INCLUDED...A TROUGH OF LOW PRESSURE ACROSS
WYOMING INTO WESTERN SOUTH DAKOTA...WITH AN ASSOCIATED FRONTAL
BOUNDARY EXTENDING FROM NORTHEAST WYOMING THROUGH THE NEBRASKA AND
SOUTH DAKOTA BORDER. THE FRONTAL SYSTEM WILL BE THE FOCUS FOR
SCATTERED THUNDERSTORMS ACROSS WESTERN AND SOUTHERN NORTH
DAKOTA...INCREASING WITH TIME THROUGH THE EARLY MORNING HOURS.
OTHERWISE...VFR CONDITIONS CAN BE EXPECTED.

&&

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

$$

UPDATE...WAA
SHORT TERM...TM
LONG TERM...MM
AVIATION...WAA