Hail and Damaging Wind in Minnesota, July 31, 2008

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
732 PM CDT THU JUL 31 2008

.UPDATE...
PUT ISOLATED THUNDERSTORMS THROUGHOUT THE AREA TONIGHT...WITH
SCATTERED THUNDERSTORMS ALONG THE CANADIAN BORDER. MADE SOME
ADJUSTMENTS TO THE WIND...DEFINING AREAS OF ONSHORE FLOW.

&&

.DISCUSSION...
A VERY BROAD EAST TO WEST JET HAS AN AXIS SOUTH OF OUR AREA. A
VERY POTENT LINE OF INTENSE THUNDERSTORMS IS MOVING EAST THROUGH
THE DRYDEN AREA OF WESTERN ONTARIO. THIS LINE IS IN THE LEFT EXIT
REGION OF THE JET...WITH CAPES APPROXIMATELY 1500 J/KG ANCPD TO
PRST ALONG THE BORDER THROUGH 12Z FRIDAY. THE SOUTHERN TIP OF THE
CANADIAN LINE APPARENTLY WILL CONTINUE TO PROPAGATE DOWN ACROSS
THE ENTIRE RAINY RIVER VALLEY...THEN MOVE THROUGH THE NORTHERN
ARROWHEAD. OUTFLOW AND INTERACTION WITH A ROBUST LAKE BREEZE
PRECLUDES RULING OUT THUNDERSTORMS FIRING UP FURTHER SOUTH. THE
STORMS ARE NORTH OF A WEAK SURFACE LOW...WITH WEAK BUT DISTINCT
SURFACE TROUGHS EXTENDING FURTHER SOUTH...INTO VERY MOIST AIR JUST
TO OUR SOUTH. WE ANCPT THE FRONT EXITING THE EASTERN PARTS OF OUR
AREA AND HIGH PRESSURE BUILDING IN...ENDING THE THUNDERSTORM
SITUATION EARLY FRIDAY MORNING.

&&

.PREV DISCUSSION... /ISSUED 256 PM CDT THU JUL 31 2008/

DISCUSSION...
FAIRLY QUIET AFTERNOON DESPITE INCREASING INSTABILITY...MSAS LIS
RANGE FROM 0 TO -4C ACROSS NE MINNESOTA. AN AREA OF STEEPER MID
LVL LAPSE RATES...6.5 C/KM TO 8 C/KM...PER LATEST RUC13
ANALYSIS...IS FCST TO MOVE TOWARDS WCRTL AND SWRN CWA LATE THIS
AFTERNOON AND EARLY THIS EVENING. CONFIDENCE IS LOW ON CONVECTION
PART OF FCST IN SHORT TERM AS LIMITED/NO ACTIVITY CURRENTLY
OCCURRING WEST OF CWA DESPITE SIMILAR FCST FIELDS. DESPITE SFC
BDRY/WINDSHIFT OVER ERN NDAK..IT APPEARS LARGE MCS TO SOUTH OF CWA
EARLY TODAY MAY HAVE DISRUPTED NORMAL INFLOW TOWARDS APPROACHING
BDRY. RESULT IS VERY SLOW FORMATION OF ENOUGH BL LIFT/CONVERGENCE
TO GENERATE RW/TRW. LATEST 88D SHOWS LAKE BREEZE HAS PUSHED WELL
INLAND.

LATE TODAY/TONIGHT...SFC BDRY WILL MOVE EAST WITH ISO/SCT RW/TRW.
STILL CONCERNED THAT FCST 0-6KM BULK SHEAR VALUES IN EXCESS OF
45KTS...AND SBCAPES AROUND 1500/2000 J/KG... IN NRN CWA COULD
ALLOW BRIEF POTENTIAL FOR STRONG/SVR STORMS LATE TODAY AND
EARLY THIS EVENING. WILL NEED TO MONITOR LATEST 88D/SFC MESOANALYSIS.
OTHERWISE EVENING CONVECTION SHOULD DISSIPATE AS LOSS OF BL HEATING
REMOVES MOST OF THE LIFT.

FRIDAY...SFC HIGH WILL MOVE EAST OVER CWA WHICH WILL ALLOW A
PLEASANT DECREASE IN SFC DEWPOINTS. INCREASING MID LVL
RIDGING/SUBSIDENCE SHOULD KEEP ABUNDANT SUNSHINE IN FCST.

EXTENDED...QUIET WEATHER INTO FIRST PART OF WEEKEND AS SFC HIGH
SLOWLY EDGES EAST. MDLS CONVERGE REASONABLY WELL ON TAKING NEXT
MID LVL SHORTWAVE ACROSS CWA SAT NIGHT/SUNDAY WITH INCREASING
LIFT/PRECIP. A NOCTURNAL LLJ APPEARS LIKELY WITH NOSE OF MSTR
TRANSPORT AIMING TOWARDS SRN CWA BY 12Z SUNDAY. TOO EARLY TO
ASCERTAIN EXTENT/MAGNITUDE OF CONVECTIVE POTENTIAL AS SFC MESO
BDRIES MAY DOMINATE BEST FORCING/HIGHEST QPF.

AVIATION...
SCT TO BKN CU FIELD COVERS THE FA WITH VFR CIGS. A FEW
LOCATIONS MAY BRIEFLY REACH MVFR NEAR CANADA AS AN UPPER LEVEL SHORT
CLIPS THE INTERNATIONAL BORDER. A STRONGER SHORT WAVE WILL PRODUCE
SCATTERED THUNDERSTORMS LATE THIS AFTERNOON INTO TONIGHT AND SHOULD
END IN ALL LOCATIONS AROUND 12Z FRIDAY. TIMING IS DIFFICULT AND IS
REFLECTED IN THE FORECASTS. VFR CONDITIONS ARE ANTICIPATED FOR
FRIDAY.

&&

POINT TEMPS/POPS...
DLH  56  81  52  78 /  20  10  10  10
INL  52  80  44  83 /  30  10  10  20
BRD  56  84  53  88 /  20  10  10  20
HYR  53  85  47  86 /  20  10  10  10
ASX  54  82  49  80 /  20  10  10  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...

MN...NONE.
WI...NONE.
LS...NONE.

EOM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DULUTH MN
443 AM CDT THU JUL 31 2008

MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-011030-
KOOCHICHING-NORTHERN ST. LOUIS-NORTHERN COOK/NORTHERN LAKE-
NORTHERN ITASCA-CENTRAL ST. LOUIS-SOUTHERN LAKE/LAKESHORE-
SOUTHERN COOK/LAKESHORE-NORTHERN CASS-SOUTHERN ITASCA-
SOUTHERN CASS-CROW WING-NORTHERN AITKIN-SOUTHERN AITKIN-
CARLTON/SOUTHERN ST. LOUIS-PINE-DOUGLAS-BAYFIELD-ASHLAND-IRON-
BURNETT-WASHBURN-SAWYER-PRICE-
443 AM CDT THU JUL 31 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST MINNESOTA AND
NORTHWEST WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT
ACROSS THE NORTHLAND. THESE STORMS ARE NOT EXPECTED TO BE
SEVERE...BUT SOME MAY CONTAIN SMALL HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE POSSIBLE SATURDAY AFTERNOON THROUGH TUESDAY
NIGHT. SOME OF THE STORMS MAY BE SEVERE THIS WEEKEND THROUGH EARLY
NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT.

LSZ121-140>148-011030-
BAYFIELD TO OAK POINT WI-GRAND PORTAGE TO GRAND MARAIS MN-
GRAND MARAIS TO TACONITE HARBOR MN-
TACONITE HARBOR TO SILVER BAY HARBOR MN-
SILVER BAY HARBOR TO TWO HARBORS MN-TWO HARBORS TO DULUTH MN-
DULUTH MN TO PORT WING WI-PORT WING TO SAND ISLAND WI-
SAND ISLAND TO BAYFIELD WI-OAK POINT TO SAXON HARBOR WI-
443 AM CDT THU JUL 31 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE NEARSHORE WATERS OF
WESTERN LAKE SUPERIOR.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
TONIGHT. THESE STORMS ARE NOT EXPECTED TO BE SEVERE...BUT SOME
MAY CONTAIN SMALL HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE POSSIBLE SATURDAY AFTERNOON THROUGH TUESDAY
NIGHT. SOME OF THE STORMS MAY BE SEVERE THIS WEEKEND THROUGH EARLY
NEXT WEEK.

LILES

MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING WEB ADDRESS:
HTTP://WWW.WEATHER.GOV/DULUTH (ALL LOWER CASE)