Tornado Warning 4, NWS Aberdeen, SD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
315 PM CDT MON JUN 15 2009

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
FORECAST CHALLENGES INCLUDE TIMING AND AREAL COVERAGE OF
THUNDERSTORMS OVER THE NEXT FEW DAYS.

CURRENTLY...A LEE-OF-THE-ROCKIES SURFACE TROF OF LOW PRESSURE
RESIDES ACROSS WESTERN SOUTH DAKOTA...WITH 60+ DEGREE DEWPOINT AIR
STREAMING NORTHWARD AHEAD OF THE TROF OVER THIS CWA. CONVECTION
HAS ALREADY BEGUN FIRING OUT ACROSS NORTHEAST WYOMING AND FAR
WESTERN SOUTH DAKOTA IN THE HIGHER TERRAIN OF THE NORTHERN HIGH
PLAINS. OVER THE FAR WESTERN ZONES OF THIS CWA...SURFACE
WIND/MOISTURE CONVERGENCE IS NOTED IN THE LAPS STREAMLINES
DATA...AND THIS IS WHERE A LINE OF CUMULUS CLOUDS HAVE DEVELOPED
THIS AFTERNOON. THERE IS ALSO 1500 TO 2500 J/KG OF CAPE NOTED
ACROSS THE FAR WESTERN ZONES WITH CONVECTIVE INHIBITION RIGHT
AROUND -20J/KG OR LESS. 0-6KM SHEAR IS ALSO AROUND 25 TO 35 KNOTS
OVER THIS AREA.

SW FLOW ALOFT WILL HOLD FOR THE NEXT COUPLE OF DAYS. 700HPA AND
500HPA S/W TROFS CONTINUE TO BE SHOWCASED IN THE MODEL DATA
RUMBLING ALONG OVER THE CENTRAL AND NORTHERN PLAINS STATES. ONE OF
THESE UPPER CIRCULATIONS CAN BE SEEN IN WATER VAPOR IMAGERY
SPINNING THROUGH SE MONTANA/NE WYOMING...WHILE TWO OTHER WAVES ARE
WORKING THROUGH SW WYOMING AND COLORADO AT THIS TIME. SUFFICE IT
TO SAY...THE ATMOSPHERE IS PRIMED FOR CONVECTION. ONE OR MORE OF
THESE UPPER WAVES WILL LIKELY PROVIDE THE SYNOPTIC SCALE KICK
NEEDED TO GET CONVECTION GOING THIS EVENING. AREAL COVERAGE IN
BETTER LOW LEVEL MOISTURE THIS EVENING SHOULD YIELD SCATTERED TO
NUMEROUS THUNDERSTORMS DEVELOPING ACROSS WESTERN SOUTH DAKOTA
/INCLUDING THE WEST RIVER FORECAST ZONES OF THIS CWA/ OVER THE
NEXT 3 TO 6 HOURS. CONVECTION SHOULD GRADUALLY SHIFT NORTH AND
EAST THROUGH LATE THIS EVENING...WITH SOME POTENTIAL FOR FURTHER
ELEVATED CONVECTIVE DEVELOPMENT ACROSS EASTERN SOUTH DAKOTA LATER
TONIGHT. SOME STORMS THIS EVENING ARE EXPECTED TO BECOME STRONG TO
SEVERE...GIVEN THE FAVORABLE COMBINATION OF INSTABILITY AND SHEAR
AROUND THIS EVENING. LARGE HAIL AND DAMAGING WINDS ARE THE MAIN
SEVERE WEATHER THREATS THIS EVENING.

DURING PEAK HEATING HOURS ON TUESDAY...ADDITIONAL S/W ENERGY WILL
BE WORKING THROUGH THE CENTRAL AND EASTERN FORECAST ZONES. ONCE
AGAIN...THERE WILL BE PLENTY OF LOW LEVEL MOISTURE AROUND TO
PRODUCE FAIRLY LARGE CAPE VALUES...ALONG WITH A SURFACE TROF AXIS
IN PLACE ACROSS THE CWA TO FIRE CONVECTION OFF OF. THE 0-6KM SHEAR
MAY BE LACKING...THOUGH...TO PRODUCE WIDESPREAD SEVERE CONVECTION.
WOULD EXPECT TO SEE SOME PULSE OR MULTI-CELLULAR CONVECTIVE
REDEVELOPMENT BY TUESDAY AFTERNOON ACROSS THE JAMES RIVER VALLEY
AND POINTS EAST.

BY TUESDAY EVENING...EXPECTING A LULL IN CONVECTIVE ACTIVITY THAT
WILL PERSIST INTO WEDNESDAY. HOWEVER...MODELS PROG ANOTHER AREA OF
LOW PRESSURE TO LIFT OUT ONTO THE CENTRAL/NORTHERN PLAINS
WEDNESDAY NIGHT. IT STANDS TO REASON THAT IF THIS AREA OF LOW
PRESSURE INITIATES CONVECTION ACROSS THE NORTHERN HIGH PLAINS OF
MONTANA/WYOMING...THERE COULD BE SOME FORM OF MESOSCALE CONVECTIVE
SYSTEM MOVING FROM WEST TO EAST ACROSS THE WESTERN/CENTRAL
FORECAST ZONES LATE WEDNESDAY NIGHT.

INHERITED POPS HAVE BEEN PUSHED BACK OUT THE DOOR...RELATIVELY
UNCHANGED. MAX/MIN TEMPERATURES WERE NUDGED UPWARDS A FEW DEGREES
ALL PERIODS...GIVEN THE PROLONGED PERIOD OF WEAK WAA TO NEUTRAL
THERMAL ADVECTION AND LOW LEVEL MOISTURE ADVECTION THAT WILL BE
AROUND THROUGH MID-WEEK. THE ONLY FLY-IN-THE-OINTMENT WOULD BE
CONVECTIVE DEBRIS CLOUDINESS THAT MIGHT KEEP THE LID ON MAX TEMPS
ON TUESDAY.

.LONG TERM...THURSDAY THROUGH MONDAY
MAIN FORECAST CHALLENGE IN THE LONG TERM IS PRECIPITATION CHANCES.
THE PERIOD STARTS OFF WITH AN UPPER LEVEL TROUGH SLIDING FROM THE
ROCKIES TO THE PLAINS...WITH DECENT SHORTWAVE ENERGY OVER THE
DAKOTAS. A SURFACE COLD FRONT WILL BE OVER THE WESTERN CWA EARLY
THURSDAY...THEN TRACKS TO THE EASTERN CWA DURING THE DAY AND EAST
OF THE REGION THURSDAY NIGHT. LIS FALL INTO THE -2 TO -6 RANGE
WITH CAPES BETWEEN 2500 AND 3500 J/KG DURING THE AFTERNOON AND
EARLY EVENING HOURS ACROSS THE EASTERN CWA. SOME SHEAR NOTED...BUT
NOT MUCH LOW OR UPPER LEVEL JET SUPPORT. FOR NOW...WILL KEEP A
CHANCE POP GOING FOR POSSIBLE THUNDERSTORMS. FRIDAY IS A LITTLE
TRICKY RIGHT NOW AS THE FRONTAL BOUNDARY BECOMES ANGLED FROM SOUTH
CENTRAL CANADA TO THE GREAT LAKES AND HIGH PRESSURE BROADENS FROM
THE ROCKIES TO THE CENTRAL AND SOUTHERN PLAINS. SOME WEAK
INSTABILITY REMAINS ACROSS THE EAST...SO HAVE OPTED TO LEAVE A
SMALL POP GOING FRIDAY FOR NOW. EXPECT TO SEE QUIET WEATHER
SATURDAY THROUGH THE DAY SUNDAY AS THE SURFACE HIGH BECOMES
DOMINANT OVER THE PLAINS. A LOW PRESSURE SYSTEM TRACKS
NORTHEASTWARD OVER THE CENTRAL PLAINS SUNDAY NIGHT BEFORE GETTING
PUSHED SOUTHWARD BY HIGH PRESSURE DROPPING OUT OF CANADA ON
MONDAY. LIS FALL INTO THE ZERO TO -4 RANGE WITH CAPES OF 1500-2500
J/KG SUNDAY NIGHT INTO MONDAY...AND THE LOW MAY BE IN THE VICINITY
LONG ENOUGH TO ALLOW FOR SOME SHOWERS AND STORMS TO DEVELOP...SO
WILL STICK WITH SOME SMALL POPS DURING THAT TIME FRAME AS WELL.

NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE
THROUGHOUT THE LONG TERM UNDER A DECENT AMOUNT OF SUN AND WITH H85
TEMPS IN THE TEENS.

&&

.AVIATION...
SCT-BKN VFR CIGS WILL BE OVER MUCH OF THE REGION THIS EVENING.
SOME LOWER CLOUDS MAY BE FOUND ACROSS THE FAR EASTERN CWA IN
ASSOCIATION WITH LIGHT RAIN SHOWERS THROUGH ABOUT 01Z...AFFECTING
KATY. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE
FAR WESTERN CWA THIS EVENING...AND MAY AFFECT KPIR AND KMBG. SOME
OF THE STRONGER STORMS MAY SEE CIGS AND VSBYS FALL INTO THE MVFR
CATEGORY...AND MAY BE CAPABLE OF PRODUCING HAIL AND STRONG WINDS.
THE CHANCE FOR RAIN WILL CONTINUE ACROSS THE ENTIRE CWA INTO
TUESDAY MORNING.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

SHORT TERM...DORN
LONG TERM...PARKIN
AVIATION...PARKIN

WEATHER.GOV/ABERDEEN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
330 AM CDT MON JUN 15 2009

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-160830-
TRAVERSE-BIG STONE-CORSON-CAMPBELL-MCPHERSON-BROWN-MARSHALL-
ROBERTS-WALWORTH-EDMUNDS-DAY-DEWEY-POTTER-FAULK-SPINK-CLARK-
CODINGTON-GRANT-HAMLIN-DEUEL-STANLEY-SULLY-HUGHES-HYDE-HAND-JONES-
LYMAN-BUFFALO-
330 AM CDT MON JUN 15 2009 /230 AM MDT MON JUN 15 2009/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MINNESOTA...CENTRAL SOUTH DAKOTA...NORTH CENTRAL SOUTH DAKOTA AND
NORTHEAST SOUTH DAKOTA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS THIS MORNING WILL REMAIN BELOW SEVERE LIMITS AS THEY
PUSH INTO NORTH DAKOTA AND WEAKEN. ANOTHER ROUND OF STORMS IS
EXPECTED WITH STORMS FIRING ACROSS WESTERN SOUTH DAKOTA THIS
AFTERNOON. THE MAIN THREAT FROM THESE STORMS WILL BE FOR HIGH
WINDS AND LARGE HAIL. STORMS WILL ALSO MOVE IN A NORTH NORTHEAST
DIRECTION WITH A SLOW EASTERLY PROGRESSION OF THE SYSTEM. THIS
COULD RESULT IN PROLONGED PERIOD OF INTENSE RAINFALL IF THE SYSTEM
ORGANIZES INTO A LINE OF STORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

AN ACTIVE PATTERN IS EXPECTED THROUGHOUT THE WORK WEEK...WITH
WEDNESDAY THE ONLY DAY THUNDERSTORMS ARE NOT FORECAST. NONE OF
THE DAYS IN WHICH THUNDERSTORMS ARE FORECAST APPEARS PARTICULARLY
FAVORABLE FOR A WIDESPREAD SEVERE WEATHER EVENT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED DURING THE LATE AFTERNOON HOURS.

CONNELLY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
821 PM CDT MON JUN 15 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0820 PM     HAIL             11 S GREEN GRASS        45.01N 101.25W
06/15/2009  E1.25 INCH       DEWEY              SD   TRAINED SPOTTER

0820 PM     HAIL             11 S GREEN GRASS        45.01N 101.25W
06/15/2009  E1.00 INCH       DEWEY              SD   LAW ENFORCEMENT

&&

ATG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
831 PM CDT MON JUN 15 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0823 PM     HAIL             11 S GREEN GRASS        45.01N 101.25W
06/15/2009  E1.50 INCH       DEWEY              SD   OTHER FEDERAL

&&

ATG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
903 PM CDT MON JUN 15 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0900 PM     HAIL             14 W MISSION RIDGE      44.69N 101.08W
06/15/2009  E1.75 INCH       STANLEY            SD   PUBLIC

&&

ATG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
920 PM CDT MON JUN 15 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0905 PM     HAIL             25 N HAYES              44.73N 101.02W
06/15/2009  E1.00 INCH       DEWEY              SD   TRAINED SPOTTER

&&

ATG

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
922 PM CDT MON JUN 15 2009

SDZ015-033-034-160300-
DEWEY-STANLEY-SULLY-
822 PM MDT MON JUN 15 2009

...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR NORTHERN
STANLEY...SOUTHERN DEWEY AND WESTERN SULLY COUNTIES UNTIL 900 PM
MDT/1000 PM CDT/...

AT 821 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 13 MILES SOUTH OF RIDGEVIEW...OR 25 MILES EAST OF
EAGLE BUTTE...MOVING SOUTHEAST AT 20 MPH.

SMALL HAIL...AND WINDS AROUND 50 MPH ARE EXPECTED WITH THIS STORM.

THE STORMS WILL REMAIN OVER MAINLY RURAL AREAS OF THE INDICATED
COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 4487 10042 4472 10065 4494 10100 4507 10073
TIME...MOT...LOC 0222Z 320DEG 19KT 4490 10074

DORN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ABERDEEN SD
929 PM CDT MON JUN 15 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0925 PM     HAIL             11 NNW SANSARC          44.65N 101.12W
06/15/2009  E1.75 INCH       STANLEY            SD   TRAINED SPOTTER

&&

ATG