MESOSCALE DISCUSSION 1598
NWS STORM PREDICTION CENTER NORMAN OK
1123 PM CDT THU JUL 03 2003
AREAS AFFECTED...CNTRL/SRN MN...NRN IA AND WRN WI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...SEVERE THUNDERSTORM
WATCH 629...630...
VALID 040423Z - 040600Z
TWO SEVERE MCS/S CONTINUE TO TRACK TOWARD THE UPPER MS VLY. BOW
ECHO NOW APPROACHING THE SD/ND/MN BORDER IS MOVING 290/47 KTS...AND
IS RIDING AN INSTABILITY GRADIENT THAT IS SITUATED SEWD TOWARD THE
MSP METRO AREA. AT THE SAME TIME...ANOTHER LONG LIVED BOW ECHO WAS
MOVING 245/50 KTS INTO SWRN MN AND NWRN IA AND IS LIKELY TO
DEVELOP/TURN MORE ELY AS IT MOVES INTO SRN MN IN A COUPLE OF HOURS.
EXTRAPOLATION WOULD MERGE THE TWO MCS/S OVER SERN MN AND WRN WI
BETWEEN 07-08 UTC. DOWNSTREAM AIR MASS IS VERY MOIST AND UNSTABLE
WITH SURFACE DEW POINTS IN THE 70S. H5 FLOW IS EXPECTED TO
STRENGTHEN CONSIDERABLY WITH AT LEAST 40 KTS OF FLOW. COMBINATION
OF MOIST BOUNDARY LAYER...WELL DEVELOPED FORWARD PROPAGATING MCS/S
AND STRENGTHENING KINEMATICS ALL POINT TO A DAMAGING WIND THREAT
CONTINUING ACROSS CNTRL/SRN MN AND NRN IA FOR SEVERAL HOURS. THIS
THREAT WILL LIKELY BE LONG LIVED AND MOVE INTO THE UPPER MS VLY
AFTER ABOUT 07 UTC.
OTHERWISE...FARTHER WEST IN WS 629...A FEW ISOLD TSTM HAVE
DEVELOPED/BEEN MAINTAINED ALONG A MYRIAD OF OUTFLOW BOUNDARIES WHERE
AIR MASS WAS NOT OVERTURNED EARLIER THIS EVENING. THESE STORMS WILL
ADVANCE EWD ACROSS SRN SD AND PROBABLY WEAKEN WITH TIME LATER
TONIGHT.
..RACY.. 07/04/2003
ATTN...WFO...DLH...MPX...FGF...ABR...BIS...DMX...FSD...OAX...LBF...UNR...GRB...MKX...DVN...ARX...
45679856 47309713 47319105 45679274
45649465 41709317 41760057 45930266
45389419 45609207 45229038 43598946 42459083 42759339
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