Severe Thunderstorm Warning 116, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
833 PM CDT FRI JUL 28 2006

.UPDATE...
PER WATER VAPOR A 500 MB SHORT WAVE WAS NOTED MOVING INTO SW
MANITOBA. AN AREA OF MOISTURE NEAR 500 MB WAS NOTED MOVING OVER
MOST OF ND EARLY THIS EVENING...AND IN AREAS OF NW SD/SW ND WHERE
TEMPS REACHED NR 110F HIGH BASED TSTMS FORMED AND ARE MOVING EAST
THRU SOUTH CENTRAL ND AND NW SD.

EXPECT SVR POTENTIAL AND TSTM COVERAGE TO INCREASE QUICKLY OVER
THE NEXT 1-3 HOURS. 850 MB WINDS WILL INCREASE TO 30-35 KTS AND
OVERRUN THE STRONG 850 MB FRONT OVER FAR SRN ND. SFC FRONT HAS
SAGGED INTO FAR NRN SD...WITH ALL OF THE FCST AREA NOW IN
NORTHEAST WINDS. VERY TIGHT TEMP/MOISTURE GRADIENT WITH FRONT
ALONG SOUTH DAKOTA BORDER WITH LOW 50 DEW PTS ALONG MANITOBA
BORDER TO MID 70 DEW PTS IN THE FAR SOUTH. ALTHOUGH THERE HAS BEEN
CONSIDERABLE MOVEMENT SOUTHWARD OF DRIER SFC AIR IN THE PAST FEW
HOURS WITH FARGO DEW PT FALLING TO NEAR 60 AT 01Z WHILE 70-75 DEW
PTS REMAIN IN THE WADENA-FERGUS FALLS-WAHPETON AREAS.

00Z BISMARCK SOUNDING SHOWS A VERY CAPPED ENVIRONMENT WITH
MOISTURE QUITE HIGH UP ROOTED ABV 12000 FT. AS LOW LEVEL JET
DEVELOPS NEXT 1-3 HOURS IT WILL HELP SPREAD SOME RICHER 850 MB
MOISTURE NORTHWARD OVER 850 THERMAL BOUNDARY ALONG SD/ND BORDER
WITH VERY LARGE INCREASES IN THETA-E EXPECTED IN THE JMS-FAR-DTL
CORRIDOR 03-06Z TIME PERIOD. THIS ADVECTION WILL SPREAD NORTHWARD
REACHING THE GFK-BJI AREA 06-09Z. ATTM TSTMS MOVING INTO JAMESTOWN
AREA ARE HIGH BASED...BUT AS 850-700 THERMAL AND MOISTURE FIELDS
GET BETTER BASED WILL LOWER AND SUFICIENT STEEP LAPSE RATES IN THE
850-500 MB LAYER FOR INCREASINGLY STRONGER TSTMS AROUND 03Z.

ALL MODELS HIGHLIGHT THE 03Z TIME PERIOD AS THE START OF THE MAIN
TSTM ACTION...WITH NAM APPEARING TO BE A BIT BETTER DEFINED.
EVOLUTION TO MCS SHOULD OCCUR PRETTY QUICKLY IN THE 06Z-09Z PERIOD TONIGHT
AND THEN EXIT MINNESOTA PART OF FCST AREA AROUND 12Z OR SO.
FREEZING LEVELS ARE QUITE HIGH IN THE 14500 TO 15000 FT
RANGE...BUT WITH ELEVATED CONVECTION AND STRONG ISENTROPIC LIFT
EXPECTED OVER THE FRONT OVERNIGHT STRONG ENOUGH UPDRAFTS SHOULD
OCCUR FOR LARGE HAIL. IN ADDITION....EXAMINATION OF DOWNDRAFT CAPE
REVEALS OVER 1500 J/KG AVBL THRU 06Z IN THE FAR SOUTH JUST NORTH
OF THE SFC FRONT. WOULD APPEAR AN AREA FROM THE SFC FRONT
NORTHWARD TO THE MIDDLE PART OF THE FCST WOULD STAND THE BEST
THREAT FOR SEVERE TONIGHT WITH WIND THREAT PROBABLY CLOSER TO
RICHER SFC MOISTURE JUST NORTH OF SFC FRONT ITSELF IN THE FAR
SOUTHERN AREAS OF THE FCST AREA.

SWODY1 AND HWOFGF CURRENTLY OUT EXPLAINS THINGS WELL AND WILL
ISSUE NOWCAST TO HIGHLIGHT THREAT FOR RAPID SEVERE DEVELOPMENT OF
CURENT ACTIVITY SPREADING INTO ECNTRL/SE ND.

&&

.PREV DISCUSSION... (ISSUED 241 PM CDT FRI JUL 28 2006)

SHORT TERM (THRU MON)...CHALLENGES ABOUND FOR THIS FORECAST
DEALING MAINLY WITH THE EVOLUTION OF AN MCS OVERNIGHT. A FAIRLY
POTENT COLD FRONT IS PUSHING SOUTH THIS AFTERNOON CURRENTLY
RESIDING ALONG A LINE FROM KINL-KPKD-KBWP. THIS FRONT IS EXPECTED
TO DROP ABOUT ANOTHER 50 MILES SE THEN STALL OUT OVERNIGHT BEFORE
RETREATING NORTH AS A WARM FRONT ON SAT. A TIGHT TEMP/DEWPOINT
GRADIENT HAS SET UP FROM NORTH TO SOUTH WITH TEMPS IN THE LOW 70S
NORTH TO AROUND 100 DEGREES NEAR THE SD BORDER. THIS GRADIENT WILL
ONLY ENHANCE THE INSTABILITY AND EFFECTIVE SHEAR NEEDED TO FUEL
STORMS TONITE. AS AN UPPER LEVEL WAVE NOW SEEN IN NORTH CENTRAL MT
SLIDES EAST...THE INTERACTION OF THIS FEATURE ALONG WITH STRONG
SURFACE HEATING AND THE BOUNDARY WILL GENERATE STORMS STRETCHING
FROM CENTRAL ND INTO NE MN.

STORMS NORMALLY FORM 50-100 MILES NORTH OF THE BOUNDARY...WHICH
WOULD PUT THE LIKELY CORRIDOR FOR THUNDER ALONG I-94. WE HAVE
SEVERAL JET STRUCTURES AT WORK TONITE WITH AN 80KT SPEED MAX
RIDING THE WESTERLIES ACROSS CENTRAL ND AND AN INCREASING H85 LLJ
OF AROUND 30KTS POKING INTO SOUTH CENTRAL ND. THIS CREATES
SUFFICIENT SPEED AND DIRECTIONAL SHEAR TO POSSIBLY SUSTAIN
SUPERCELLS, WITH A BOW ECHO STRUCTURE MORE LIKELY. THE
THUNDERSTORM COMPLEX SHOULD PROPAGATE W-E WITH A SOUTHERLY TURN AS
THE LLJ VEERS CLOSER TO DAY BREAK ON SAT. THE STORMS SHOULD MOVE
SWIFTLY, BUT WITH UP TO 2 INCHES OF PRECIPITABLE WATER...VERY
HEAVY RAIN IS ANOTHER CONCERN. UNFORTUNATELY...NOT EVERYONE WILL BE
IMPACTED BY THIS COMPLEX, BUT THOSE WHO SEE RAIN MAY GET MORE THAN
THEY BARGAINED FOR.

AS THE WARM FRONT RETREATS NORTH TOWARD THE CANADIAN BORDER BY
EARLY SUNDAY...VERY HOT AIR WILL BE PULLED NORTH. MORE OF A
SOUTHWESTERLY TRAJECTORY SETS UP ON SUN...WHICH IS A WARMING
WIND...ALLOWING TEMPS TO EASILY EXCEED 100 DEGREES IN CENTRAL ND
TAPERING TO THE MID 90S FURTHER NORTH AND EAST. ALSO DURING THIS
TIME...DEWPOINTS REMAIN QUITE HIGH IN THE MID 60S RESULTING IN
SWELTERING HEAT INDEX VALUES WELL OVER 105 DEGREES.

THE HOT AIR WILL EFFECTIVE CAP US OFF FROM MUCH IF ANY CONVECTIVE
DEVELOPMENT FROM SUN ON...BUT STORMS MAY TRY TO FORM ON THE
PERIPHERY OF THE WARM AIR IN NRN MN...ESPECIALLY DURING THE
OVERNIGHT HOURS AS THE NOCTURNAL LLJ INCREASES. FINALLY THE
OFFENDING LOW PRESSURE SYSTEM AND ASSOCIATED FRONTS MAKE SOME
EASTWARD PROGRESS ON MON...BUT IT SHOULD BE ANOTHER HOT DAY EAST
OF THE RED RIVER WHERE SOUTHERLY WINDS WILL PREVAIL FOR ONE MORE
DAY.

LONG TERM (TUES THRU FRI)...GENERALLY ZONAL PATTERN FOR THE EARLY
FORECAST PERIOD...WITH EMBEDDED SHORT WAVE SWINGING THROUGH ON
TUESDAY...OFFERING BEST PRECIP. CHANCES TO THE SOUTH AND EAST.
THIS TO BE FOLLOWED BY ANOTHER SWITCH TO NORTHWEST FLOW THURSDAY
AND FRIDAY...ACCOMPANIED BY SEASONAL CONDITIONS WITH DAILY HIGHS
NOT TOO FAR FROM 80. KEPT FORECAST DRY DURING THIS TIME
FRAME...BUT INEVITABLY CHANCES FOR ISOLATED TRW WILL OCCUR IN THE
NORTHWEST FLOW.

AVIATION...INTRODUCED PROB30/TEMPO FOR SCATTERED THUNDER LATER THIS
EVENING AND OVERNIGHT AS STORM COMPLEX MOVES THROUGH AREA.
TRW RELATED WINDS MAY HAVE TO BE BOLSTERED IN NEW TAF ISSUANCE.

&&

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

RIDDLE

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GRAND FORKS ND
319 PM CDT FRI JUL 28 2006

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-292030-
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-
319 PM CDT FRI JUL 28 2006

...SEVERE THUNDERSTORMS POSSIBLE ACROSS EASTERN NORTH DAKOTA AND
WESTERN MINNESOTA OVERNIGHT...

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL DEVELOP THIS EVENING AND MOVE EAST OVERNIGHT.
THE PRIMARY THREAT FROM THESE STORMS WILL BE POTENTIALLY DESTRUCTIVE
WINDS AND POSSIBLY LARGE HAIL. THE PRIME TIME FOR STORMS WILL
MAINLY BE FROM AROUND MIDNIGHT TO 7 AM ON SATURDAY.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

STORMS WILL BE ONGOING EARLY SATURDAY MORNING THEN VERY WARM AIR
WITH POTENTIALLY LIFE THREATENING HEAT INDICIES OVER 100 DEGREES
ENTER THE PICTURE FOR SUNDAY AND MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

JCA/AYD

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
927 PM CDT FRI JUL 28 2006

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

0440 PM     HAIL             4 SE HALLOCK            48.73N 96.88W
07/27/2006  E0.88 INCH       KITTSON            MN   PUBLIC

0440 PM     TSTM WND DMG     4 SE HALLOCK            48.73N 96.88W
07/27/2006                   KITTSON            MN   PUBLIC

            SIGNIFICANT TREE DAMAGE DUE TO STRAIGHT LINE WINDS.

0450 PM     FUNNEL CLOUD     3 ESE KENNEDY           48.63N 96.85W
07/27/2006                   KITTSON            MN   PUBLIC

            A FUNNEL CLOUD BEGAN TO DEVELOP UNDER A PERSISTENT WALL
            CLOUD FORMATION AND WAS VIEWED BY A FARMER IN HIS FIELD
            SOUTHEAST OF KENNEDY. THE WALL CLOUD APPEARED TO TURN TO
            THE RIGHT OF ITS ORIGINAL SOUTHEAST PATH AND TOWARDS A
            MORE SOUTHERLY DIRECTION AT THAT POINT. A TORNADIC
            TOUCHDOWN INITIATED SEVERAL MINUTES LATER EAST OF
            DONALDSON.

0458 PM     HAIL             5 ENE DONALDSON         48.60N 96.80W
07/27/2006  M2.75 INCH       KITTSON            MN   NWS STORM SURVEY

            SEVERAL SQUARE MILES OF CROPS WERE SHATTERED OR FLATTENED
            BY LARGE HAIL IN EASTERN DAVIS AND WESTERN SPRINGBROOK
            TOWNSHIPS.

0501 PM     HAIL             4 E DONALDSON           48.57N 96.81W
07/27/2006  E1.75 INCH       KITTSON            MN   LAW ENFORCEMENT

0502 PM     TORNADO          3 ENE DONALDSON         48.59N 96.84W
07/27/2006  F1               KITTSON            MN   NWS STORM SURVEY

            A TORNADO TOUCHED DOWN IN A FIELD JUST NORTH OF HIGHWAY
            11 AND TRAVELED FOR ABOUT 3.5 MILES BEFORE IT ENDED IN
            MARSHALL COUNTY. TORNADIC WINDS SNAPPED SEVERAL
            COTTONWOOD TREES AT A HOMESTEAD AND SWIRLED TREE BRANCHES
            AROUND THE YARD. SMALLER TREE BRANCHES WERE LOFTED OVER A
            MILE TO THE SOUTH BY THE TORNADO AND CROPS WERE SWIRLED
            BY THE WINDS. THE TORNADO CONTINUED SOUTH BY
            SOUTH-SOUTHEAST AND CROSSED INTO MARSHALL COUNTY ABOUT 5
            ESE OF DONALDSON AROUND 509 PM. PEAK WINDS ARE ESTIMATED
            AT 80 MPH.

0504 PM     HAIL             9 NE STEPHEN            48.54N 96.74W
07/27/2006  E1.75 INCH       MARSHALL           MN   PUBLIC

0509 PM     TORNADO          6 NNE STEPHEN           48.53N 96.83W
07/27/2006  F1               MARSHALL           MN   NWS STORM SURVEY

            A TORNADO CONTINUED FROM KITTSON COUNTY INTO MARSHALL
            COUNTY AND TRACKED FOR ABOUT 1 MORE MILE TO THE SOUTH
            UNTIL 512 PM. THE TORNADO BLEW OVER A ROAD SIGN AND
            CAUSED ADDITIONAL EXTREME WIND STRESS AS CROPS WERE
            SWIRLED BY THE WINDS. PEAK WINDS SPEEDS WERE ESTIMATED TO
            80 MPH.

0629 PM     HAIL             13 SW THIEF RIVER FALLS 47.98N 96.37W
07/27/2006  E0.88 INCH       PENNINGTON         MN   PUBLIC

            MARBLE TO NICKEL SIZED HAIL CONTINUED FOR ABOUT 5 MINUTES
            NEAR THE RED LAKE COUNTY LINE UNTIL 634 PM.

0630 PM     HAIL             1 NE DOROTHY            47.94N 96.43W
07/27/2006  M0.88 INCH       RED LAKE           MN   PUBLIC

            MARBLE TO NICKEL SIZED HAIL CONTINUED FOR ABOUT 5 MINUTES
            UNTIL 635 PM.

0637 PM     FUNNEL CLOUD     1 SSE DOROTHY           47.91N 96.44W
07/27/2006                   RED LAKE           MN   AMATEUR RADIO

            A PERSISTENT WALL CLOUD WITH DEVELOPING FUNNEL WAS
            OBSERVED MOVING TO THE SOUTH-SOUTHEAST. A TOUCHDOWN LATER
            OCCURED EAST OF HUOT.

0644 PM     HAIL             RED LAKE FALLS          47.89N 96.27W
07/27/2006  E1.00 INCH       RED LAKE           MN   CO-OP OBSERVER

0646 PM     TORNADO          1 E HUOT                47.87N 96.40W
07/27/2006  F0               RED LAKE           MN   NWS STORM SURVEY

            A TORNADO TOUCHED DOWN INTERMITTENTLY ALONG A 2.5 MILE
            TRACK TO THE SOUTH. THE TORNADO CROSSED INTO POLK COUNTY
            AFTER TRAVELING A LITTLE OVER ONE MILE. IT EXITED RED
            LAKE COUNTY ABOUT 1.5 MILES SOUTHEAST OF HUOT AT ABOUT
            650 PM. THE TORNADO SWIRLED SWATHS OF GRAIN AND FLIPPED A
            SHED DOOR UP ONTO THE SHED ROOF. IT ALSO BROKE OFF
            NUMEROUS LARGE TREE BRANCHES IN SHELTERBELTS ALONG ITS
            PATH. PEAK WINDS ARE ESTIMATED AT ABOUT 65 MPH.

0650 PM     TORNADO          4 NNE GENTILLY          47.84N 96.42W
07/27/2006  F0               POLK               MN   NWS STORM SURVEY

            THE TORNADO CROSSED FROM RED LAKE COUNTY INTO POLK COUNTY
            AND CONTINUED FOR ABOUT 1.5 MILES. THE TORNADO BROKE
            NUMEROUS LARGE BRANCHES IN VARIOUS SHELTER BELTS ALONG
            ITS ROUTE AND LIFTED ABOUT 2.5 MILES NE OF GENTILLY
            AROUND 654 PM. PEAK WINDS ARE ESTIMATED AT 65 MPH.

0654 PM     FUNNEL CLOUD     14 NW MENTOR            47.84N 96.36W
07/27/2006                   POLK               MN   TRAINED SPOTTER

0657 PM     TORNADO          4 SSW RED LAKE FALLS    47.83N 96.31W
07/27/2006  F0               RED LAKE           MN   AMATEUR RADIO

            A WALL CLOUD AND FUNNEL WAS ORIGINALLY REPORTED AND
            TRACKED BY TWO TRAINED SPOTTERS WHOSE VIEW OF THE SURFACE
            WAS OBSCURED BY TREES. A STORM SURVEY CONFIRMED AN
            INTERMITTENT SURFACE TRACK FOR ABOUT 2.5 MILES WHICH
            ENDED ABOUT 6 MILES SOUTH OF RED LAKE FALLS BY ABOUT 708
            PM. NUMEROUS LARGE TREE BRANCHES WERE BROKEN OFF IN
            SHELTER BELTS ALONG THE ROUTE AND LARGE HAY BALES WERE
            TUMBLED. ESTIMATED PEAK WIND SPEEDS WERE ABOUT 70 MILES
            AN HOUR.

0709 PM     HAIL             3 SE GENTILLY           47.76N 96.40W
07/27/2006  E1.00 INCH       POLK               MN   PUBLIC

0710 PM     HAIL             7 SW TERREBONNE         47.76N 96.24W
07/27/2006  M2.50 INCH       RED LAKE           MN   PUBLIC

            QUARTER TO TENNIS BALL SIZED HAIL FELL FOR ABOUT 5
            MINUTES UNTIL 715 PM. HAIL CROSSED INTO POLK COUNTY.

0711 PM     HAIL             6 NW MENTOR             47.76N 96.24W
07/27/2006  M2.50 INCH       POLK               MN   PUBLIC

            HAIL FROM QUARTER TO TENNIS BALL SIZED HAIL FELL FOR
            ABOUT 5 MINUTES UNTIL 716 PM.

0724 PM     HAIL             MENTOR                  47.70N 96.14W
07/27/2006  E1.00 INCH       POLK               MN   PUBLIC

0729 PM     HAIL             3 SW MENTOR             47.67N 96.19W
07/27/2006  M1.75 INCH       POLK               MN   TRAINED SPOTTER

0745 PM     HAIL             4 S MENTOR              47.64N 96.14W
07/27/2006  E1.00 INCH       POLK               MN   PUBLIC

0746 PM     TSTM WND GST     7 SW ERSKINE            47.59N 96.12W
07/27/2006  E65.00 MPH       POLK               MN   PUBLIC

            DAMAGING WINDS AND HAIL TO THE SIZE OF GOLF BALLS HIT
            PORTIONS OF UNION LAKE. NUMEROUS LARGE TREE BRANCHES AND
            SMALLER TREES WERE WERE SNAPPED OFF. HEAVY LOG BUILT LAWN
            FURNITURE AND A SMALL STORAGE SHED WERE BLOWN AROUND.

0747 PM     HAIL             5 S ERSKINE             47.59N 96.01W
07/27/2006  M0.75 INCH       POLK               MN   TRAINED SPOTTER

0752 PM     HAIL             6 W WINGER              47.54N 96.11W
07/27/2006  E0.88 INCH       POLK               MN   TRAINED SPOTTER

0758 PM     HAIL             3 W WINGER              47.54N 96.05W
07/27/2006  M2.00 INCH       POLK               MN   TRAINED SPOTTER

            HAIL FROM QUARTER TO HEN EGG SIZED COVERING THE ROAD.
            ESTIMIMATED WIND GUSTS TO 45 MILES AN HOUR.

0800 PM     HAIL             4 N BEJOU               47.50N 95.97W
07/27/2006  E1.00 INCH       MAHNOMEN           MN   PUBLIC

0800 PM     HAIL             WINGER                  47.54N 95.99W
07/27/2006  E1.75 INCH       POLK               MN   PUBLIC

0802 PM     HAIL             3 NE RANUM              47.49N 96.09W
07/27/2006  M0.75 INCH       NORMAN             MN   PUBLIC

            MARBLE TO PENNY SIZED HAIL COVERED THE GROUND.

0827 PM     HAIL             4 NE MAHNOMEN           47.36N 95.91W
07/27/2006  E0.88 INCH       MAHNOMEN           MN   PUBLIC

&&

GGUST