MKC MCD 251728
SDZ000-MNZ000-252000-

SPC MESOSCALE DISCUSSION #1481 FOR NE SD/CNTRL MN
CONCERNING...CONVECTIVE TRENDS/SEVERE THUNDERSTORM POTENTIAL...

WE ARE MONITORING CONVECTIVE DEVELOPMENT ACROSS REGION.
LOW-LEVEL WARM ADVECTION AND FORCING FOR UPWARD VERTICAL MOTION IN
LEFT EXIT REGION OF UPPER JET STREAK HAVE SUPPORTED SCATTERED
THUNDERSTORMS PAST SEVERAL HOURS ACROSS PARTS OF EASTERN NORTH
DAKOTA AND NORTHWEST MINNESOTA. LATEST VISIBLE IMAGERY INDICATES
NEW CONVECTIVE ACTIVITY IS BEGINNING TO FORM WITH DAYTIME HEATING
IN MOIST TONGUE AHEAD OF SURFACE COLD FRONT WHICH EXTENDS SOUTHWARD
INTO AREAS NEAR FARGO ND/ABERDEEN SD. HOWEVER...SIGNIFICANT
CAPPING IN THE 850 MB TO 700 MB LAYER STILL APPEARS TO BE IN
PLACE...AND MAY IN FACT INCREASE SLIGHTLY WITH LOW-LEVEL WARM
ADVECTION OVER PARTS OF EASTERN SOUTH DAKOTA AND SOUTHWEST
MINNESOTA THIS AFTERNOON. THIS WILL TEND TO INHIBIT DEEPENING
SURFACE-BASED CONVECTION NEAR FRONT ACROSS THIS REGION...WITH
BETTER THREAT LIKELY AFTER 21Z...AS LARGE-SCALE AND DESTABILIZATION
LIFT INCREASES AHEAD OF FRONT ACROSS CENTRAL MINNESOTA...WHERE/WHEN
VERTICAL SHEAR PROFILES/INSTABILITY WILL SUPPORT THREAT FOR SEVERE
THUNDERSTORMS.


..KERR.. 07/25/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL
ACUS3 KMKC 251946
MKC MCD 251946
MNZ000-252200-

SPC MESOSCALE DISCUSSION #1482 FOR MN
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 618

WE WILL CONTINUE TO MONITOR CENTRAL/SOUTHERN MINNESOTA FOR
POSSIBILITY OF AN ADDITIONAL WW.

UPWARD VERTICAL MOTION FIELD FORCED BY MID-LEVEL VORTICITY CENTER
CONTINUES TO SUPPORT CLUSTERS OF STRONG/SEVERE THUNDERSTORMS ACROSS
NORTHWEST MINNESOTA FROM BEMIDJI TO FERGUS FALLS...WHILE LOW-LEVEL
WARM ADVECTION EAST OF DEVELOPING WARM FRONT AHEAD OF UPPER SYSTEM
APPEARS TO BE PROVIDING SUPPORT FOR CLUSTER OF STORMS NORTH OF ST.
CLOUD. LARGE HAIL WILL LIKELY BE MAIN THREAT WITH THIS ACTIVITY...
WHICH WILL CONTINUE TO INCREASE IN COVERAGE ACROSS NORTH CENTRAL
MINNESOTA LATE THIS AFTERNOON.

TO THE SOUTH...SURFACE COLD FRONT IS NOW EAST OF FARGO ND AND
ABERDEEN SD...AND WILL CONTINUE EASTWARD WITH DIGGING UPPER TROUGH
CURRENTLY OVER THE DAKOTAS. AS TEMPERATURES AHEAD OF FRONT HEAT
INTO THE MID/UPPER 80S DURING THE NEXT 2 TO 3 HOURS...AND LARGE-
SCALE FORCING FOR UPWARD VERTICAL MOTION INTENSIFIES OVER PARTS OF
CENTRAL/SOUTHERN MINNESOTA...MID-LEVEL CAP EVIDENT IN RAOBS WILL
WEAKEN SUFFICIENTLY FOR INCREASING/INTENSIFYING THUNDERSTORM
ACTIVITY. STRENGTHENING MID-LEVEL FLOW WILL ENHANCE VERTICAL SHEAR
PROFILES...WHICH MODELS SUGGEST WILL BE SUFFICIENT FOR SUPERCELLS

...POSSIBLY WITH ISOLATED TORNADOES GIVEN ENVIRONMENT WITH CAPE OF
2000 TO 4000 J/KG.

GREATEST RISK APPEARS TO BE NEAR WEAK SURFACE LOW...NOW SOUTHWEST
OF BEMIDJI MN...AS IT DEVELOPS SOUTHEASTWARD INTO AREAS NEAR/
SOUTHWEST OF ST. CLOUD BY 26/00Z.


..KERR.. 07/25/00

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC MKCSWOMCD ALL
ACUS3 KMKC 252306
MKC MCD 252306
MNZ000-SDZ000-260100-

SPC MESOSCALE DISCUSSION #1483 FOR...CENTRAL AND SRN MN...
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 619...

STORMS WERE INCREASING ALONG CONVERGENCE AND INSTABILITY AXIS
SITUATED JUST WEST OF A LINE FROM FSD TO STC. LATEST DIAGNOSTIC
DATA WAS SHOWING SURFACE BASED CAPE OVER 3000 J/KG IN THIS
AREA...AS WELL AS A SURFACE PRESSURE FALL CENTER. THEREFORE...
EXPECT ACTIVITY TO CONTINUE TO INCREASE AS IT MOVES TOWARD SOUTH-
CENTRAL MN.

SURFACE WINDS WERE VEERED AHEAD OF THIS CONVECTION RESULTING IN
STORM RELATIVE HELICITY GENERALLY LESS THAN 100 M2/S2. HOWEVER...
INCREASING DEEP LAYER SHEAR OF 30-40 KT WILL SUPPORT SUPERCELL
STRUCTURE ESPECIALLY NEAR THE TAIL END OF THE LINE. IN
ADDITION...VISIBLE SATELLITE IMAGERY SUGGESTS AN OUTFLOW BOUNDARY
FROM ERN STORMS HAS DROPPED ACROSS MEEKER AND KANDIYOHI COUNTIES...
POSSIBLY INTERSECTING STORMS NEAR WILLMAR. THIS OUTFLOW COULD
LOCALLY ENHANCE SRH AND RESULT IN LOW LEVEL UPDRAFT ROTATION.
21Z RUC2 WAS FORECASTING 50-55 KT 500 MB SPEED MAX TO MOVE ACROSS
ERN SD THROUGH 03Z. THIS INCREASING MID LEVEL FLOW INTO THE BACK OF
THE CONVECTIVE LINE WILL INCREASE DAMAGING STRAIGHT LINE WIND
POTENTIAL.


..CARBIN.. 07/25/00
NNNN
ZCZC MKCSWOMCD ALL
ACUS3 KMKC 260226
MKC MCD 260226
MNZ000-IAZ000-260400-

SPC MESOSCALE DISCUSSION #1484 FOR...SRN MN...NRN IA...
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 620...

LARGE COLD POOL HAS EVOLVED OVER WEST CENTRAL MN AND WILL AID LOW
LEVEL CONVERGENCE AND LIFT ALONG LEADING EDGE OF SURFACE
TROUGH/WINDSHIFT CURRENTLY ANALYZED ALONG A FSD TO MSP LINE.
AT LEAST TWO SUPERCELL THUNDERSTORMS WERE LOCATED ALONG THE TROUGH
LINE... ONE MOVING TOWARD BLUE EARTH COUNTY MN AND THE OTHER OVER
NOBLES COUNTY MN AND OSCEOLA COUNTY IA. ANOTHER SUPERCELL MAY BE
ASSCOCIATED WITH A MESOLOW AT THE INTERSECTION OF OUTFLOW FROM NWRN
WI CONVECTION. THIS ACTIVITY WAS WITHIN SURFACE BASED INSTABILITY
AXIS WITH 2500-3500 J/KG CAPE. LOW TO MID LEVEL JET STREAK /50 KT
AT 700 MB/ MOVING OVER THE AREA WILL MAINTAIN DEEP LAYER SHEAR
FAVORABLE FOR STORM ROTATION. LATEST MSP VWP DATA SUGGESTS 0-3 KM
HELICITY HAS INCREASED TO ABOUT 200 M2/S2 GIVEN A STORM MOTION OF
290/25. THEREFORE THE THREAT FOR ISOLATED TORNADOES CONTINUES
WITHIN WW.


..CARBIN.. 07/26/00
NNNN
ZCZC MKCSWOMCD ALL
ACUS3 KMKC 260405
MKC MCD 260405
IAZ000-NEZ000-SDZ000-260600-

SPC MESOSCALE DISCUSSION #1485 FOR...NWRN IA/ERN NEB/EXTREME SERN
SD...
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...REF WW 621...

VIGOROUS CONVECTION TAKING PLACE ALONG STRONGLY CONVERGENT SURFACE
TROUGH MOVING SEWD ACROSS NWRN IA ATTM. AIRMASS OVER THE MISSOURI
RIVER VALLEY IS VERY MOIST AND UNSTABLE WITH SURFACE BASED CAPE
2500-3000 J/KG. REGIONAL VWP AND PROFILER DATA WAS SHOWING LOW
LEVEL VEERING AHEAD OF THE TROUGH INDICATIVE OF WARM AIR ADVECTION
AND ASCENT. MEANWHILE...NEW UPDRAFTS WERE DEVELOPING JUST NORTH OF
THE TROUGH...OVER SERN SD. SOME BACKBUILDING UPDRAFTS ARE EXPECTED
INVOF SURFACE TROUGH AS IT DEVELOPS INTO ERN NEB. HOWEVER...
RELATIVELY WEAK LOW LEVEL JET MAY BE OFFSET BY STRONGER MID LEVEL
FLOW WITH STRONGEST UPDRAFTS CONTINUING TO PROPAGATE SEWD AT ABOUT
20 KT. GIVEN STRONG DEEP LAYER SHEAR OF AROUND 50 KT STORMS SHOULD
CONTINUE TO EXHIBIT SOME ORGANIZATION WITH SMALL SCALE BOWS/LEWPS
PRODUCING DAMAGING WINDS AND HAIL.


..CARBIN.. 07/26/00
NNNN