MESO: Mesoscale Discussion 0960

ACUS11 KWNS 062012
SWOMCD
SPC MCD 062012
IAZ000-MOZ000-NEZ000-062215-

MESOSCALE DISCUSSION 0960
NWS STORM PREDICTION CENTER NORMAN OK
0312 PM CDT SAT JUN 06 2009

AREAS AFFECTED...PARTS OF SE IA...NW MO INTO CNTRL IA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 062012Z - 062215Z

TRENDS ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT.
UNCERTAINTIES STILL EXIST...BUT A WW COULD BECOME NECESSARY PRIOR TO
22-23Z.

STRONG LOW-LEVEL CONVERGENCE/WARM ADVECTION APPEARS FOCUSED NEAR AND
JUST EAST OF A FRONTAL WAVE ACROSS THE MID MISSOURI VALLEY... WHERE
SURFACE HEATING AND INCREASING DEW POINTS ARE CONTRIBUTING TO
BOUNDARY LAYER DESTABILIZATION. RUC GUIDANCE SUGGESTS MIXED LAYER
CAPE IS NOW IN EXCESS OF 1500 J/KG...WITH INDICATIONS OF WEAKENING
MID-LEVEL INHIBITION...PARTICULARLY FOR BOUNDARY LAYER PARCELS NEAR
THE OMAHA AREA. THIS APPEARS LIKELY TO WEAKEN FURTHER DURING THE
NEXT FEW HOURS...WITH THE SUPPRESSION OF THE THERMAL RIDGE NEAR 700
MB...ASSOCIATED WITH PASSAGE OF A WEAK MID-LEVEL IMPULSE WITHIN THE
STRONG SOUTHWESTERLY MID/UPPER FLOW ACROSS THE REGION. AT THE SAME
TIME...THE APPROACH OF ANOTHER LOW AMPLITUDE WAVE WILL MAINTAIN
LOW-LEVEL WARM ADVECTION...AND THIS FORCING MAY SUPPORT THE
INITIATION OF AT LEAST ISOLATED STORM DEVELOPMENT TOWARD THE 23-00Z
TIME FRAME. IN THE PRESENCE OF STRONG DEEP LAYER SHEAR BENEATH 50+
KT 500 MB FLOW...THE ENVIRONMENT WILL BE FAVORABLE FOR SUPERCELLS
CAPABLE OF PRODUCING LARGE HAIL.

THE PRECISE LOCATION OF STORM INITIATION IS STILL NOT CLEAR...BUT IT
SEEMS MOST PROBABLE EAST OF THE OMAHA AREA INTO THE DES MOINES
VICINITY. WHILE THIS ACTIVITY MAY INITIALLY FORM ABOVE A SHALLOW
WEAK NEAR-SURFACE STABLE LAYER...SIZABLE CLOCKWISE CURVED LOW-LEVEL
HODOGRAPHS NEAR A 30-40 KT SOUTHERLY LOW-LEVEL JET WILL SUPPORT
POTENTIAL FOR TORNADOES AND DAMAGING WIND GUSTS.

..KERR.. 06/06/2009

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

ATTN...WFO...DMX...EAX...FSD...OAX...

LAT...LON 41979645 42599523 42419362 41989245 41229257 40329380
40069533 40239652 41979645

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