SPC MD 1882

MD 1882 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR ERN NEB THROUGH EXTREME SERN SD INTO WRN IA


MESOSCALE DISCUSSION 1882
NWS STORM PREDICTION CENTER NORMAN OK
0508 PM CDT TUE SEP 04 2012

AREAS AFFECTED...ERN NEB THROUGH EXTREME SERN SD INTO WRN IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 042208Z - 042345Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...STORMS DEVELOPING OVER ERN NEB MAY BECOME CAPABLE OF
PRODUCING ISOLATED DAMAGING WIND AND LARGE HAIL. OTHER STORMS MAY
INCREASE OVER WRN IA LATER THIS EVENING. CONVECTIVE TRENDS ARE BEING
MONITORED FOR A POSSIBLE WW.

DISCUSSION...EARLY THIS EVENING A DRYLINE/CONVERGENCE TROUGH AXIS
EXTENDS FROM CNTRL NEB SWWD INTO NWRN KS. A WEAKER CONVERGENCE
BOUNDARY EXISTS OVER SERN NEB. TEMPERATURES HAVE WARMED INTO THE
UPPER 90S TO 100 F AND DEWPOINTS HAVE MIXED INTO THE 40S RESULTING
IN DEEPLY MIXED AND WEAKLY CAPPED BOUNDARY LAYERS. INSTABILITY
REMAINS AOB 1000 J/KG ACROSS MOST OF ERN NEB TO THE WEST OF PRIMARY
MOIST AXIS WITH MUCH STRONGER INSTABILITY WITH EWD EXTENT INTO IA.
HIGH BASED STORMS SHOULD CONTINUE DEVELOPING ALONG PREVIOUSLY
MENTIONED BOUNDARIES AND MAY INTENSITY AS THEY ADVANCE EWD. STEEP
LAPSE RATES AND DRY SUBCLOUD LAYERS WILL PROMOTE A THREAT OF
ISOLATED DAMAGING WIND. LARGE HAIL IS ALSO POSSIBLE...ESPECIALLY AS
STORMS DEVELOP EWD AND INTERCEPT STRONGER INSTABILITY.

OTHER STORMS MAY DEVELOP LATER THIS EVENING FROM NERN NEB INTO WRN
IA WITHIN ZONE OF INCREASING WARM ADVECTION AND ISENTROPIC ASCENT
ASSOCIATED WITH STRENGTHENING SWLY LLJ. THESE STORMS WILL ALSO POSE
A THREAT FOR ISOLATED DAMAGING WIND AND LARGE HAIL.

..DIAL/THOMPSON.. 09/04/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FSD...OAX...GID...LBF...

LAT...LON   40369781 41369818 42519837 42879814 42799692 41769555
            40499608 40369781

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1882.html