Severe Thunderstorm Warning 40, NWS Aberdeen, SD

AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
220 PM CDT MON JUN 19 2000

FCST FOCUS ON SVR PTNTL TNGT AND CLDS/TMPS/PCPN FOR TUES AND WED.

STG LO OVR NW SD PRODUCING MOIST SLY FEED INTO CWA WITH SFC DPTS IN
THE LOW TO MID 60S. MSAS LI'S DOWN TO -6 DESPITE CLDS STILL HANGING
ARND. GOES SOUNDER DATA INDICATES CAPES OF 1500 J/KG OVR OUR CWA
WITH OVER 2000 J/KG IN NEB. DOPPLER RADAR SHWS CONSISTENT BAND OF
LGT SHWRS IN OUR WRN CWA WITH SVR PTNTL PROBABLY DVLPG E OF THAT
AREA. SWOMCD ISSUED BY SPC CONCERNING CNTL SD WITH POSSIBLE WATCH
COMING UP. TRIGGER IS SHORT WAVE IN WY AND CO WITH QUITE A BIT OF
LTG ASSOC WITH IT. PROFILER NETWORK SHWS SLY LLJ IN THE PLNS OF
30-40 KTS.  CAN ALRDY SEE NICE DRY PUNCH IN WRN NEB WITH SFC DWPTS
IN THE 40S. WITH CDFNT PUSHING INTO AREA FM W TO E LATE THIS AFTN
AND TNGT INTO UNSTABLE ATMOS AHD OF STRENGHENING LLJ XPCT SVR TSTMS
TO DVLP. WET BULB ZERO HT OF 13K SEEMS WAY TOO HI TO GENERATE LRG
HAIL AT THE SFC SO MAIN THREAT TO BE DAMAGING WINDS AS WND FIELD
STRENGTHENS. STILL WUD LIKE TO SEE STRGR MID LVL WNDS BUT WE WILL
SEE HOW THIS ALL PANS OUT. XPTG AN ACTIVE EVE/NGT THO.

MJR UPR LO TO ROTATE FAIRLY SIGGY SHORT WAVES ACRS CWA ON TUES. WITH
PROGGED NEG LI'S AND SFC DWPTS STILL IN THE 50S AND COLDER AIR ALF
XPCT SHWRS/TSTMS LIKELY ERN CWA. ONLY A CHC IN THE WEST DUE TO DRIER
AIR. ON WED AVN BRINGS COLD POCKET OF COLDER THAN -20C AT H5 BUT SFC
DWPTS LWR INTO THE 40S BY THEN. STILL SHD BE BKN INSTABILITY CLDS
AND WILL GO WITH SML POP FOR SHWRS.

WILL BE QUITE WINDY ARND HERE TUES THRU WED WITH INTNS SFC LO
TRACKING FM N OF MN TO LKSUP AND H8 WINDS OF 30-40 KTS.

FAN/FWC TMPS/POPS LOOK GOOD AND CANT REALLY ARGUE AGAINST IT.

...EXTENDED DISCUSSION...
AFTER LOOKING AT THE VARIOUS LONG RANGE AND 12Z SHORT RANGE
DATA...IT APPEARS THE DEVIL IS IN THE DETAILS. HAVE DECIDED TO STICK
WITH THE MRF AS IT WAS FAIRLY WELL SUPPORTED BY 12Z AVN ALTHO THE
AVN IS NOW A TAD STRONGER WITH THE NEXT TROF MOVG THRU THE PACIFIC
NW. AS BIG FOR JUNE SYSTEM DEPARTS TO THE EAST BY THU A FLAT RIDGE
BUILDS OVER THE NORTHERN PLAINS JUST AHEAD OF NEXT WEAKER UPPER
TROF. TIMING DISTURBANCES RIDING THE RIDGE WILL BE TOUGH. HOWEVER
MOST MODELS LEAN TOWARD SOME ACTION FOR FRI AND SAT. NOT SURE ON THE
AREAL COVERAGE OF PCPN BUT FEEL I NEED TO INCLUDE RISK IN FORECAST.
OVERALL TEMPS FROM THE MEX AND FMR LOOKED IN THE BALLPARK AND WERE
FOLLOWED.

.ABR...NONE.
JH
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