780
ACUS11 KWNS 092334
SWOMCD
SPC MCD 092334
MNZ000-IAZ000-NEZ000-SDZ000-100100-
MESOSCALE DISCUSSION 1504
NWS STORM PREDICTION CENTER NORMAN OK
0634 PM CDT THU JUL 09 2009
AREAS AFFECTED...SW MN...SE SD...NW IA...NE NEB
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 092334Z - 100100Z
A SEVERE THREAT IS EXPECTED TO DEVELOP FROM CNTRL MN SSWWD INTO SERN
SD AND NE NEB OVER THE NEXT FEW HOURS. LARGE HAIL AND ISOLATED WIND
DAMAGE SHOULD BE THE PRIMARY THREATS. A WW WILL LIKELY BE NEEDED
EARLY THIS EVENING ACROSS THE REGION.
LATEST SFC ANALYSIS SHOWS A LOW OVER FAR NE SD WITH A COLD FRONT
EXTENDING SWWD ACROSS ERN SD AND A STATIONARY FRONT EXTENDING SWD
INTO NW IA. BETWEEN THE TWO BOUNDARIES...THE RUC IS ANALYZING
MODERATE INSTABILITY. A FEW THUNDERSTORMS HAVE DEVELOPED ON THE NRN
END OF THE INSTABILITY AXIS IN CNTRL MN. OTHER STORMS APPEAR LIKELY
TO INITIATE ALONG AND JUST AHEAD OF THE COLD FRONT IN THE SIOUX
FALLS AREA THIS EVENING EVENTUALLY DEVELOPING SWD INTO THE NORFOLK
NEB AREA. REGIONAL WSR-88D VWPS THROUGH THIS CORRIDOR SHOW MODERATE
TO STRONG VERTICAL SHEAR WHICH WILL BE SUFFICIENT FOR SEVERE STORMS
AS THE EXIT REGION OF A 65-70 KT MID-LEVEL JET APPROACHES FROM THE
WEST THIS EVENING. IF A FEW SUPERCELLS CAN ORGANIZE...LARGE HAIL AND
AN ISOLATED TORNADO THREAT WOULD EXIST. HOWEVER...DUE TO THE LINEAR
NATURE OF THE FORCING ALONG THE FRONT...LINE-SEGMENTS MAY BE THE
PREFERRED STORM MODE. HAIL AND WIND DAMAGE WILL BE POSSIBLE
ESPECIALLY AS STORM COVERAGE INCREASES IN THE MID TO LATE EVENING.
..BROYLES.. 07/09/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MPX...FSD...OAX...LBF...
LAT...LON 41839750 41939822 42449847 43059780 43929676 44779610
45429581 45519541 45319517 44919500 44059502 42879577
42149672 41839750
000
ACUS11 KWNS 092334
SWOMCD
SPC MCD 092334
MNZ000-IAZ000-NEZ000-SDZ000-100100-
MESOSCALE DISCUSSION 1504
NWS STORM PREDICTION CENTER NORMAN OK
0634 PM CDT THU JUL 09 2009
AREAS AFFECTED...SW MN...SE SD...NW IA...NE NEB
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 092334Z - 100100Z
A SEVERE THREAT IS EXPECTED TO DEVELOP FROM CNTRL MN SSWWD INTO SERN
SD AND NE NEB OVER THE NEXT FEW HOURS. LARGE HAIL AND ISOLATED WIND
DAMAGE SHOULD BE THE PRIMARY THREATS. A WW WILL LIKELY BE NEEDED
EARLY THIS EVENING ACROSS THE REGION.
LATEST SFC ANALYSIS SHOWS A LOW OVER FAR NE SD WITH A COLD FRONT
EXTENDING SWWD ACROSS ERN SD AND A STATIONARY FRONT EXTENDING SWD
INTO NW IA. BETWEEN THE TWO BOUNDARIES...THE RUC IS ANALYZING
MODERATE INSTABILITY. A FEW THUNDERSTORMS HAVE DEVELOPED ON THE NRN
END OF THE INSTABILITY AXIS IN CNTRL MN. OTHER STORMS APPEAR LIKELY
TO INITIATE ALONG AND JUST AHEAD OF THE COLD FRONT IN THE SIOUX
FALLS AREA THIS EVENING EVENTUALLY DEVELOPING SWD INTO THE NORFOLK
NEB AREA. REGIONAL WSR-88D VWPS THROUGH THIS CORRIDOR SHOW MODERATE
TO STRONG VERTICAL SHEAR WHICH WILL BE SUFFICIENT FOR SEVERE STORMS
AS THE EXIT REGION OF A 65-70 KT MID-LEVEL JET APPROACHES FROM THE
WEST THIS EVENING. IF A FEW SUPERCELLS CAN ORGANIZE...LARGE HAIL AND
AN ISOLATED TORNADO THREAT WOULD EXIST. HOWEVER...DUE TO THE LINEAR
NATURE OF THE FORCING ALONG THE FRONT...LINE-SEGMENTS MAY BE THE
PREFERRED STORM MODE. HAIL AND WIND DAMAGE WILL BE POSSIBLE
ESPECIALLY AS STORM COVERAGE INCREASES IN THE MID TO LATE EVENING.
..BROYLES.. 07/09/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MPX...FSD...OAX...LBF...
LAT...LON 41839750 41939822 42449847 43059780 43929676 44779610
45429581 45519541 45319517 44919500 44059502 42879577
42149672 41839750
862
ACUS11 KWNS 092257
SWOMCD
SPC MCD 092257
OKZ000-KSZ000-TXZ000-100100-
MESOSCALE DISCUSSION 1503
NWS STORM PREDICTION CENTER NORMAN OK
0557 PM CDT THU JUL 09 2009
AREAS AFFECTED...NWRN OK...NERN TX AND ERN OK PANHANDLES...SWRN KS
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 092257Z - 100100Z
ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH EARLY EVENING WITH THE
POTENTIAL FOR DRY MICROBURSTS.
A SUBSTANTIAL HIGH BASED CU FIELD EXISTS ACROSS THE AREA WHERE
TEMPERATURES HAVE RISEN TO NEAR 110 F. A WEAK SURFACE LOW IS
EXPECTED TO PERSIST AS WELL THROUGH THE EVENING...WHICH WILL
MAINTAIN SOME LOW LEVEL CONVERGENCE. A SLY LOW LEVEL JET IS ALSO
MAINTAINING PRECIPITABLE WATER VALUES TO NEAR 1.20 INCHES...AS
MEASURED BY GPS WATER VAPOR SENSORS OVER NW OK...AND WHERE DEWPOINTS
ARE HOLDING IN THE UPPER 50S TO NEAR 60 F.
ALTHOUGH SOME SUBSIDENCE LIKELY EXISTS ALOFT UNDER THE
RIDGE...CONTINUED LOW LEVEL CONVERGENCE...ALTHOUGH WEAK...MAY
COMBINE WITH A MODERATE LOW LEVEL JET IMPINGEMENT WHICH IS BRINGING
MOISTURE INTO A WELL MIXED BOUNDARY LAYER RESULTING IN ISOLATED
STORMS. EXCESSIVE DCAPE VALUES OVER 2000 J/KG SUGGEST LOCALLY
DAMAGING MICROBURST WINDS MAY OCCUR WITH ANY ACTIVITY.
..JEWELL.. 07/09/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...ICT...OUN...DDC...AMA...
LAT...LON 37219805 36649813 36379887 36209972 36150026 36360073
36710113 37100104 37859953 37829897 37679838 37219805
