Severe Thunderstorm Warning 52, NWS Aberdeen, SD

AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
230 PM CDT SAT JUL 01 2000

MAIN FORECAST CHALLENGES TONIGHT AND NEXT COUPLE OF DAYS FOCUS ON
PRECIP/THUNDERSTORM CHANCES...AND POSSIBLILITY OF SEVERE WX
ESPECIALLY THIS EVE/TONIGHT. MODELS IN FAIR AGREEMENT ON OVERALL TRENDS
NEXT 48 HOURS OR SO...BUT AS USUAL DIFFER ON THE CRITICAL DETAILS.
WILL FOLLOW ETA/NGM BLEND...LEANING TOWARD ETA FOR MAIN DETAILS. AVN
APPEARED TO UNDER-INITIALIZE STRENGTH OF UPSTREAM H5/H7 TROUGH AND
ASSOCIATED VORT MAX. ATMOSPHERE OVER MOST OF CWA SEEMS QUITE PRIMED
FOR THUNDERSTORMS...A FEW QUITE POSSIBLY SEVERE IN THE BUNCH...VERY
LATE AFTN AND THIS EVE...CONTINUING OVERNIGHT FAR EASTERN PORTION OF
AREA. TEMPS NEAR OR ABOVE 90F WHILE DEW POINTS GENERALLY IN 60S. ABR
19Z T/TD 92/69F. MONITORING GOES SOUNDER DATA...CINH VALUES HAVE
BEEN DROPPING STEADILY ACROSS THE AREA...AND EXPECT CAP TO BE FULLY
ERODED BY LATE AFTN. 17Z GOES LIS VARY FROM AROUND -2C EASTERN SD
TO -7C CENTRAL SD WITH CAPES IN 2500-3500 J/KG RANGE CNTL AND
EASTERN SD. LAPS SOUNDINGS SUPPORT THIS...IF NOT HIGHER INSTABILITY.
GOOD VEERING WIND PROFILE ALSO EVIDENT IN LAPS SOUNDINGS. ABR VWP
HAS GOOD DATA THROUGH 9 KFT AND IS SIMILAR. 4 HR LOOP OF GOES PW
SHOWS INCREASING MOISTURE ESPECIALLY SOUTH CENTRAL AND EASTERN SD.
ETA/NGM HAVE FRONTAL BOUNDARY DROPPING SOUTH FROM ND...AT 19Z
BOUNDARY APPEARS TO BE JUST SOUTH OF BIS AND JUST NORTH OF JMS. WITH
BOUNDARY CONTINUING TO DRIFT SOUTH...AND A SFC LOW OVER WESTERN SD
DRIFTING EAST...AND H5 VORT MAX RIDING OVER FRONTAL BOUNDARY LATER THIS
EVE/TONIGHT...ELEMENTS COMING TOGETHER FOR GOOD TSTM PROBABILITY MAINLY
EASTERN 1/2 OF CWA THIS EVENING/TONIGHT. ETA 250/300 MB DIVERGENCE
SHOWS A DIVERGENCE MAXIMUM STRENGTHENING OVER EASTERN SD-MN
TONIGHT...SUGGESTING POSSIBLE MCS FORMING AS COVECTION DEVELOPS AND
MERGES TOGETHER OVER EASTERN CWA. WILL MENTION PSBL SVR TSTMS THIS
EVE/TONIGHT...WITH MAIN EMPHASIS EASTERN SD/W CNTL MN. FOR
SUNDAY...DOUBTS EXIST AS TO DETAILS...BUT BELIEVE BOUNDARY WILL
SLIDE JUST TO OUR SOUTH AND WEST...WITH SLIGHTLY DRIER/COOLER AIR
FILTERING IN AS BRIEF H5/H7 RIDGE REDEVELOPS OVER AREA...AND WILL
INDICATE PTLY SUNNY IN FCST. THIS IS SUBJECT TO CHANGE OF COURSE IN
SUBSEQUENT FCST PACKAGES. NEXT GOOD CHANCE APPEARS TO BE LATER...ON
MON...AS THE BOUNDARY SHIFTS BACK NORTH AND EAST...AND ANOTHER VORT
MAX MOVES EAST-NORTHEAST OVER FAR N PLAINS. MAIN ENERGY CENTER MAY
BE JUST NORTH OF OUR AREA AS SUGGESTED BY ETA. FOR TEMPS...GENERALLY
FOLLOWED A COMPROMISE OF FWC/MAV/FAN GUIDANCE...LEANING MORE TOWARD
FWC. THANKS FOR ALL THE COORD. OZF OUT SHORTLY.

...EXTENDED FORECAST DISCUSSION...
A SFC LOW WILL MOVE SLOWLY EAST THROUGH THE CWA MONDAY NIGHT AND
TUESDAY...BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. ANOTHER
WEAK SHORT WAVE WILL MOVE THROUGH THE NORTHERN PLAINS ON
WEDNESDAY...WHICH WILL CONTINUE A CHANCE OF SHOWERS AND THUNDERSTORM
ACROSS THE CWA.  BY THURSDAY...A SFC HIGH WILL MOVE SOUTHEAST OUT OF
CANADA BRINGING WEAK NORTHERLY WINDS AND MORE STABILIZED
CONDITIONS...THUS MOSTLY DRY WEATHER CONDITIONS.  TEMPS WILL REMAIN
AROUND NORMAL THROUGH THE PERIOD.

.ABR...NONE.

LORENS/SALMONS