Severe Thunderstorm Warning 76, NWS Duluth, MN

AREA FORECST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
230 PM CDT MON JUN 1 1998

FORECAST FOCUS TONIGHT IS ON PRECIPITATION CHANCES AND SEVERE
POTENTIAL ACROSS SOUTHERN CWA.

ETA AND NGM IN GENERAL AGREEMENT BUT ETA HANDLING SHORTWAVE MOVING
INTO NORTHERN MONTANA BETTER THAN NGM AND ETA FORECASTING MORE QPF.
THE ETA IS ALSO FORECASTING MORE UNSTABLE CONDITIONS THIS AFTERNOON
AND EVENING WITH HIGHER SURFACE DEWPOINTS THAN NGM. SURFACE MAP
SHOWS THAT THE USUALLY MORE MOIST ETA IS UNDERFORECASTING DEWPOINTS
IN PARTS OF SOUTHERN MN CWA AT 18Z...THEY ARE IN THE LOWER TO MIDDLE
50S ATTM.

SOUTHWEST FLOW ADVECTING IN WARMER AIR AND HIGHER DEWPOINTS CAUSING
AIRMASS TO BECOME MORE UNSTABLE. 18Z SURFACE MAP SHOWING LOWER TO
MIDDLE 50S SURFACE DEWPOINTS ACROSS MUCH OF WESTERN AND SOUTHERN MN
CWA. SATELLITE AND LOOK OUT WINDOW SHOW CU/ACCAS DEVELOPED EARLY
THIS AFTERNOON AND LAPS DATA SHOWING LI/S FROM -2 IN SUPERIOR/DULUTH
AND SIREN TO -6 OVER SOUTHERN CASS CO. WITH CAPES RANGING FROM 1800
IN SOUTHERN CASS CO. TO 200 IN SUPERIOR/DULUTH. SIGNIFICANT H8 WARM
AIR ADVECTION(WAA) WASN/T SUPPLYING ENOUGH LIFT  TO CREATE
PRECIPITATION FURTHER SOUTH OF WARM FRONT...BUT LAST COUPLE OF RADAR
IMAGES SHOWING SHOWERS DEVELOPING. SIGNIFICANT LIFT WILL COME FROM VORT MAX
THAT WILL TRACK THROUGH NORTH DAKOTA THIS EVENING AND CONVERGENCE
ALONG LOW PRESSURE SYSTEM. THE SURFACE LOW SHOULD CONTINUE TO TRACK
SOUTHEAST AND 2 TO 4MB PRESSURE FALLS WERE OCCURRING ACROSS
MINNESOTA. IT APPEARS THIS EVENING WILL BE FAIRLY ACTIVE ACROSS
SOUTHERN CWA BUT BY 06Z MOST OF MN CWA GETS INTO CAA AND NW WI
STARTS CAA BEFORE 12Z.

FEEL WITH LOW WET BULB ZERO HEIGHTS...SUFFICIENT INSTABILITY...
GOOD CONVERGENCE AND LOW LEVEL SHEAR WITH FRONTAL SYSTEM...SEVERE
STORMS ARE POSSIBLE MAINLY SOUTH OF CASS LAKE TO DULUTH TO HURLEY.
THE STORMS SHOULD CONTINUE TO FIRE LATE THIS AFTERNOON AND CONTINUE
THIS EVENING.

FAN/FWC GUIDANCE TEMPERATURES CLOSE AND ACCEPTED.

MELDE