Severe Thunderstorm Warning 167, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1014 AM CDT SAT AUG 12 2006

.SHORT TERM...
POTENTIAL IS THERE FOR A VERY ACTIVE LATE AFTN/EVE SEVERE WEATHER
WISE...BUT AS ALWAYS THE DEVIL IS IN THE DETAILS. AS USUAL...EACH
MODEL HAS ITS GOOD AND BAD. HAVE NOT VIEWED 12Z GFS AS OF THIS AFD
THOUGH...BUT 06Z GFS 300 MB DIVERGENCE SEEMS TO BE DOING A NICE
JOB IN SHOWING TWO AREAS OF CONVECTION AT 00Z...ONE BULLSEYE OF
DIVERGENCE IN SOUTHERN MANITOBA...MORE LIKELY ASSOC WITH 500 MB
UPPER LOW OVER CNTRL SASK...AND THE OTHER BULLSEYE OVER SE ND/NE
SD...ASSOC WITH SFC WARM FRONT AND SFC LOW. FOCUS OF THE 12Z
NAM/RUC IS WITH THE SOUTHERN ONE AND IT WOULD APPEAR FAR SOUTHEAST
ND INTO ERN SD AND WCNTRL MN IS ONE AREA WHERE CONSENSUS IS GOOD
THAT SVR WEATHER IS LIKELY TO OCCUR...SOMETIME IN THE 21Z TO 06Z
TIME PERIOD. SFC LOW CURRENTLY NORTH OF PHILLIPS SD WILL MOVE
NORTHEAST TO JUST NORTH OF ABERDEEN THEN INTO FAR SOUTHEAST ND AT
03Z. WITH THIS TRACK...NAM SHOWS STRONG 0-2 KM VGP VALUES OF .4 TO
.5 AND 0-1 KM EHI VALUES OF .2 TO .3 AND VERY LOW LCL LEVELS BELOW
1 KM. ALL OF THESE FACTORS BODE WELL FOR SUPERCELLS WITH TORNADIC
POTENTIAL RIGHT NEAR LOW AND SURFACE BOUNDARY FROM FARGO SOUTH AND
EAST INTO NE SD/WCNTRL MN.

FURTHER NORTH...VGP VALUES NOT AS HIGH BUT A BIT MORE COOLING AT
MID LEVELS WITH FRONT TO AID IN SVR TSTM DEVELOPMENT OVER NRN
VALLEY INTO FAR NW MN THIS AFTN/EVE. UNSURE OF CVRG OF SVR IN THIS
AREA.

WATER VAPOR SHOWS DISTINCT DEEP MOISTURE PLUME FROM ARIZONA INTO
SOUTHERN NORTH DAKOTA WITH PWATS INCREASING TO 2+ INCHES OVER FAR
SE ND BY 00Z. INGREDIENTS THERE FOR HEAVY RAIN FOR SURE...BUT
SINCE NOTHING HAPPENED LAST NIGHT IN THAT AREA NOT COMFORTABLE
ISSUING A FLASH FLOOD WATCH QUITE YET AS CONFIDENCE IN EXACT
PLACEMENT OF CONVECTION IS STILL NOT HIGH ENOUGH YET DESPITE THE
ABOVE DISCUSSION. MIGHT BE BEST TO HANDLE COUNTY TO COUNTY FFW
INSTEAD OF JUST BROADBRUSHING A WATCH.

TEMPS TODAY ARE TRICKY. AREAS OF MID AND HIGH CLOUDS OVER
AREA...AND LOWER CLOUDS DEVELOPED ON QUE RIGHT AFTER 12Z IN OUR
MOIST SOUTHEASTERLY FLOW. SOME BREAKS IN THE CLOUDS OVER SOUTHEAST
ND INTO CNTRL ND...BUT THICKER CLDS IN NORTHERN AREAS. MAY LOWER
TEMPS A TAD...BUT HESISTANT TO DO MUCH AS JUST A LITTLE SUN IS
NEEDED TO RAISE TEMPS TO ABOVE 80.

&&

.PREV DISCUSSION... (ISSUED 420 AM CDT SAT AUG 12 2006)

DISCUSSION...MAIN FORECAST CHALLENGE IS PRECIPITATION. WHEN LOOKING
AT THE LATEST SURFACE ANALYSIS...AN AREA OF LOW PRESSURE IS CENTERED
IN W SD WITH A WARM FRONT EXTENDING THROUGH ND ALONG A BIS TO DVL TO
HCO LINE. ON KMVX...THE THUNDERSTORM ACTIVITY HAS REMAINED CONFINED
TO NE ND...ALONG AND E OF THE WARM FRONT IN THE FEED OF 65+
DEWPOINTS. WHEN COMPARING MODELS...NAM AND GFS SIMILAR WITH SYSTEM
EVOLUTION...BUT GFS APPEARS TO HAVE A BETTER HANDLE ON TEMPERATURE
PROFILE. THUS...LEANED TOWARD GFS FOR FORECAST. WITH CAP EXPECTED TO
INTENSIFY THROUGH THE REMAINDER OF THE NIGHT...ADDITIONAL CONVECTIVE
DEVELOPMENT IN THE CURRENT WATCH AREA APPEARS UNLIKELY. WITH BEST
THUNDERSTORM ACTIVITY MOVING E OF CURRENT WATCH AREA...WILL ALLOW
SEVERE THUNDERSTORM WATCH TO EXPIRE ON TIME.

CONSIDERING THAT ANTICIPATED THUNDERSTORM ACTIVITY DID NOT DEVELOP
IN MUCH OF E ND...WILL NOT HAVE AS MUCH CLOUD COVER AND SHOULD BE
ABLE TO HEAT OUT EARLIER IN THE DAY. WITH THE LOW PRESSURE SYSTEM
AND WARM FRONT REMAINING IN VICINITY...AREA IS SET UP NICELY FOR
ANOTHER ROUND OF SEVERE WEATHER WHICH COULD DEVELOP BY LATE
AFTERNOON. THE LOW AND ASSOCIATED FRONT IS EXPECTED TO MOVE E
THROUGH THE AREA ON SAT NIGHT...PROVIDING THE BEST POTENTIAL FOR
THUNDERSTORMS AND SEVERE WEATHER. AS A RESULT...INCREASED POPS TO
LIKELY AND KEPT SEVERE WORDING IN THE GRIDS.

ON SUN...THE LOW PRESSURE SYSTEM MOVES E OF THE AREA WITH HIGH
PRESSURE BUILDING IN FROM THE W. HOWEVER...STILL KEPT A LOW POP FOR
THUNDERSTORMS DURING THE DAY ON SUN AS THE 500MB TROF SWINGS
THROUGH. FOR SUN NIGHT INTO EXTENDED FORECAST...KEPT FORECAST DRY AS
HIGH PRESSURE DOMINATES THROUGH WED. OTHERWISE...MINOR CHANGES TO
REST OF EXTENDED FORECAST.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

RIDDLE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND FORKS ND
649 AM CDT SAT AUG 12 2006

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-131200-
WEST POLK-NORMAN-CLAY-KITTSON-ROSEAU-LAKE OF THE WOODS-
WEST MARSHALL-EAST MARSHALL-NORTH BELTRAMI-PENNINGTON-RED LAKE-
EAST POLK-NORTH CLEARWATER-SOUTH BELTRAMI-MAHNOMEN-
SOUTH CLEARWATER-HUBBARD-WEST BECKER-EAST BECKER-WILKIN-
WEST OTTER TAIL-EAST OTTER TAIL-WADENA-GRANT-TOWNER-CAVALIER-
PEMBINA-BENSON-RAMSEY-EASTERN WALSH COUNTY-EDDY-NELSON-
GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT-
RICHLAND-WESTERN WALSH COUNTY-
649 AM CDT SAT AUG 12 2006

...THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS OVER EASTERN NORTH
DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA THIS AFTERNOON AND
TONIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH
DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS OVER EASTERN NORTH
DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA THIS AFTERNOON AND
TONIGHT. AN AREA OF LOW PRESSURE WILL MOVE THROUGH THE REGION TODAY...
PROVIDING THE FOCUS FOR THUNDERSTORM DEVELOPMENT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE IS A CHANCE FOR THUNDERSTORMS OVER PARTS OF EASTERN NORTH
DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA ON SUNDAY AND
WEDNESDAY NIGHT THROUGH FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON AND
TONIGHT.

NG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
200 PM CDT SAT AUG 12 2006

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

0145 PM     HAIL             1 NW KNOX               48.35N 99.70W
08/12/2006  E0.75 INCH       BENSON             ND   PUBLIC

&&

JANDERSO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
223 PM CDT SAT AUG 12 2006

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

0205 PM     HAIL             2 N LEEDS               48.32N 99.44W
08/12/2006  E0.75 INCH       BENSON             ND   PUBLIC

&&

DRIDDLE