MESO: Mesoscale Discussion 1416

ACUS11 KWNS 222002
SWOMCD
SPC MCD 222001
WIZ000-IAZ000-222100-

MESOSCALE DISCUSSION 1416
NWS STORM PREDICTION CENTER NORMAN OK
0301 PM CDT THU JUL 22 2010

AREAS AFFECTED...SRN WI...EXTREME NERN IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 222001Z - 222100Z

VIS SATELLITE IMAGERY REVEALS A DEVELOPING CU FIELD BENEATH A BKN
CIRRUS DECK OVER MUCH OF THE REGION...AND A THICKENING CLOUD BAND
ALONG AND TO THE N OF A NEARLY STATIONARY WARM FRONTAL ZONE. AS THE
ENVIRONMENT BECOMES INCREASINGLY UNSTABLE...THUNDERSTORM INITIATION
APPEARS MORE LIKELY...WITH A THREAT FOR DAMAGING WINDS...LARGE
HAIL...AND PERHAPS AN ISOLATED TORNADO. THE AREA IS BEING MONITORED
FOR A WW.

LATEST SFC ANALYSIS PLACES A QUASI-STATIONARY WARM FRONTAL ZONE
ACROSS SRN WI...WITH TEMPERATURES HEATING INTO THE MID/UPPER 80S TO
THE S OF THIS BOUNDARY. OBJECTIVE ANALYSIS FIELDS INDICATE MLCAPE
VALUES OF AROUND 1000-2000 J/KG EXIST WITHIN THIS AIR MASS.
PERSISTENT RAINFALL HAS BEEN OCCURRING JUST N OF THE FRONTAL ZONE
WITHIN A STABLE AIR MASS ASSOCIATED WITH BROAD WARM ADVECTION
REGIME. AS FURTHER CLEARING/DESTABILIZATION OCCURS OVER SRN WI AND
EXTREME NERN IA...AN INCREASING THREAT FOR THUNDERSTORMS WILL
EXIST...WITH SOME CAPABLE OF PRODUCING DAMAGING WINDS AND LARGE
HAIL.

THE NEAR-PARALLEL ORIENTATION OF THE DEEP-LAYER SHEAR VECTOR WITH
THE FRONTAL ZONE WILL FAVOR A SLOW-MOVING OR NEARLY STATIONARY LINE
OF THUNDERSTORMS. ALTHOUGH STORM MODE IS NOT FAVORABLE FOR TORNADO
DEVELOPMENT...STRONG LOW-LEVEL SHEAR /20-25 KTS 0-1 KM SHEAR PER
POINT FORECAST HODOGRAPHS/ MAY YIELD AT LEAST A LOW POTENTIAL FOR AN
ISOLATED TORNADO IF EMBEDDED SUPERCELLS CAN DEVELOP. A THREAT FOR
HEAVY RAINFALL WILL ALSO EXIST. THE AREA WILL CONTINUE TO BE
MONITORED FOR INDICATIONS OF CONVECTIVE INITIATION...AND SUBSEQUENT
NEED FOR A WW.

..ROGERS.. 07/22/2010

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

ATTN...WFO...MKX...DVN...ARX...

LAT...LON 42498882 42549055 42789133 43109168 43329152 43459053
43478985 43268862 42898781 42548791 42498882

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