Damaging Wind in Minnesota, April 30, 2001

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
225 PM CDT MON APR 30 2001

...WINDS AND SHOWER/THUNDERSTORM THREAT FORECAST CONCERNS...

ONE SHORT WAVE LIFTING OUT MN THIS AFTN...FOLLOWED BY SMALL ZONE OF
NVA AND MINI SFC HIGH PRES RIDGE IN CNTRL ND. REGION TEMPORARILY IN
BETWEEN STRONG UPPER LEVEL JETS...AS WATER VAPOR SHOWS IMPRESSIVE
JET BLASTING INTO PAC NW WITH BAND OF MOISTURE ORGANIZING INTO ERN
MT WHERE JET IS INTERSECTING SFC TROF. MINI WAVES ON THE FAST ZONAL
FLOW ARE PROMOTING ENOUGH COOLER AIR ALOFT AND INSTABILITY FOR
REGION OF HIGH BASED CU AND SPRINKLES NOW APPROACHING WRN CWA.

.SHORT TERM...
AVN INITIALIZED WELL WITH CURRENT UPPER AIR PATTERN...AND WL FOLLOW
CLOSEST TO THIS SOLUTION. ELONGATED VORT STRUCTURE TO SAIL THRU RRV
EARLY THIS EVE...WITH A FEW ISOLD SHOWERS FROM MID CLOUDS. BRIEF
QUIET PERIOD AROUND 06Z TO BE FOLLOWED BY NEXT UPSTREAM WAVE RACING
ALONG 130KT UPPER LEVEL JET BY 12Z. HEIGHT FALLS NOW IN SASK WILL
INDUCE NEXT LOW PRES WITH TROF NEAR A KBIS-KMOT LINE BY 12Z. LOW
LEVEL WINDS WILL BACK AROUND TO THE S...BUT MOISTURE ADVECTION WILL
BE SCANT. MODELS INDICATE IMPRESSIVE 700MB UVM BY 12Z AND 850MB JET
DOES INCREASE TO 40KTS RRV AND W. HOWEVER...SFC-850 DEW PTS WILL BE
VERY DRY...AND SHOWALTERS REMAIN ABOVE ZERO ALL NGT. APPEARS UVM IS
RELATED TO STRONG 700MB WARM ADVECTION AND EXIT REGION OF UPPER
LEVEL JET AND IMPRESSIVE 250MB DIVERGENCE. MOISTURE IS CENTERED FROM
750MB AND HIGHER WITH 850MB DEW PTS BLO ZERO. WL KEEP LOW POP THREAT
FOR FEW HIGH BASED SHRA AROUND 12Z IN MAINLY NE ND. TEMPS WL FALL
QUICKLY EARLY WITH DRY AIR IN PLACE...BUT SHOULD RECOVER/STABILIZE
LATE AS WAA AND S WIND COMMENCES.

.LONG TERM...DIFFERENCES IN MODELS APPEARS AS NGM/AVN/CANADIAN MORE
SIMILAR THAN ETA BUT AVN STRONGEST ON WINDS. REGARDLESS...LOOKS LIKE
WINDY/COOLER/UNSETTLED MID WEEK PATTERN. STRONG UPPER LOW WILL
TRAVERSE CANADIAN BORDER AS SFC TROF MOVES THRU RRV MIDDAY. EXPECT
GENERAL QPF UNDER QUARTER INCH WITH PASSAGE...WITH MAIN PROBLEM
BECOMING STRONG W WINDS BY LATE AFTN IN WRN ZONES AS
SUBSIDENCE...Q-VECTOR DIVERGENCE AND COLD ADVECTION...COMBINE WITH
UNIDIRECTIONAL FLOW ALOFT UNDER JET CORE BRINGING DOWNWARD MOMENTUM
TRANSPORT. MAV WINDS INDICATE SUSTAINED IN THE 35KT RANGE...WITH
ETA/NGM BIT MORE TAME. FIRE WX MAY ALSO BECOME A CONCERN IF DEW PTS
LOWER INTO THE 20S ON ND SIDE BY LATE AFTN...YIELDING RED FLAG
CONDITIONS. WL PASS ALONG PSBL NEED FOR WIND HEADLINES ON TUE TO
NEXT SHIFT. ANY DEEPER MOISTURE IS QUICKLY SHUNTED OFF TO THE
SE...WITH TSRA THREAT CONFINED WELL SE OF CWA BY 00Z MON. BREEZY
CONDITIONS WL CONTINUE THRU MON NGT AS UPPER LOW CAPTURES SFC SYSTEM
IN SW ONTARIO AND A SECONDARY COLD FRONT SWINGS THRU CWA WED
BRINGING SHOWERS TO NRN ZONES. TEMPS ON A DOWNWARD TREND NEXT FEW
DAYS AS 850MB TEMPS FALL TO 2C BY WED.

.EXTENDED....500 MB SPLIT FLOW REGIME WITH CLOSED LOW VICINITY OF
THE SOUTHWESTERN STATES SHOULD RESULT IN DRY PERIOD THURSDAY THROUGH
SATURDAY AS SURFACE HIGH BUILDS OVER THE NORTHERN PLAINS. CONVECTIVE
THREAT INCREASES OVER THE WEEKEND AS CLOSED LOW LIFTS NORTHEAST INTO
PLAINS IN RESPONSE TO STRONG UPSTREAM KICKER OVER PACIFIC NORTHWEST.
NEAR SEASONABLE TEMPERATURES EARLY IN PERIOD SHOULD GIVE WAY TO
WARMING TREND ON BACKSIDE OF HIGH OVER WEEKEND.

COORD WITH BIS.

.FGF...NONE

SOROKA/BERG