Mesoscale Discussion 370

Issued

Mar 27, 2012, 8:43 PM CDT (01:43 UTC)

Expired

Mar 27, 2012, 10:45 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

The St Louis radar (KLSX), 198 km from the middle of the area, began a volume at 01:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

673 
ACUS11 KWNS 280143
SWOMCD
SPC MCD 280143 
INZ000-ILZ000-IAZ000-MOZ000-KSZ000-280345-

MESOSCALE DISCUSSION 0370
NWS STORM PREDICTION CENTER NORMAN OK
0843 PM CDT TUE MAR 27 2012

AREAS AFFECTED...PORTIONS NRN/WRN IL...EXTREME NERN/N-CENTRAL
KS...EXTREME NWRN INDIANA...WRN/NRN MO...EXTREME SERN IA...EXTREME
SRN LM.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 280143Z - 280345Z

GRADUAL DEEPENING OF CONVECTION HAS BEEN NOTED IN PREFRONTAL BAND
FROM N-CENTRAL IL TO NERN MO...WITH POTENTIAL MOVEMENT ACROSS SRN LM
REGION AND POSSIBLE BACKBUILDING TOWARD KS/MO BORDER REGION DURING
NEXT FEW HOURS.  OCNL SVR HAIL OR DAMAGING GUSTS ARE POSSIBLE.

01Z SFC MESOANALYSIS SHOWED COLD FRONT FROM E-CENTRAL WI SWWD ACROSS
DBQ/OTM/STJ AREAS.  WARM FRONT WAS DRAWN FROM ERN WI SSEWD ACROSS
CHI AREA TO NEAR SDF...HOWEVER RELATIVELY DRY SFC AIR WITH MID-UPPER
40S F DEW POINTS EXTENDED W OF WARM FRONT OVER ERN IL.  GIVEN SWLY
FLOW ON BOTH SIDES OF COLD FRONT...FRONTAL CONVERGENCE WAS
WEAK...AND SHOULD REMAIN SO THROUGH AT LEAST 04Z.  HOWEVER...SFC
CONFLUENCE LINE WAS EVIDENT OVER W-CENTRAL/N-CENTRAL IL.  THOUGH AT
OBLIQUE ANGLE TO DEVELOPING CONVECTION...STRONGEST LOW-LEVEL LIFT
APPEARS TO BE NEAR SFC CONFLUENCE ZONE.  MOIST AXIS WAS DRAWN ABOUT
35-45 NM AHEAD OF FRONT OVER MOST OF AREA.  850 AND 925 MB UPPER AIR
CHARTS SHOWED MOIST AXES AT THOSE LEVELS NEARLY COLLOCATED FROM
PNC-MKC-PIA.  00Z UPPER AIR CHARTS AND LATEST VWP/PROFILER WINDS
INDICATED LLJ AXIS SLIGHTLY FARTHER S NEAR OKC-COU-SBN LINE.

CONVECTION HAS DEVELOPED AHEAD OF FRONT...ALONG SRN FRINGE OF
LOW-LEVEL MOIST PLUME...S OF MOIST AXES AND N OF LLJ.  MOIST
ADVECTION...AND INCREASING ISENTROPIC ASCENT...SHOULD HELP TO
MAINTAIN THIS ACTIVITY AND PERHAPS INCREASE COVERAGE...WHILE BAND
TRANSLATES EWD 20-25 KT AND EMBEDDED CELLS MOVE FASTER NEWD. 
MODIFIED DVN/ILX/TOP/SGF RAOBS...ORD ACARS SOUNDING AND RUC FCST
SOUNDINGS SUGGEST 1000-1500 J/KG MLCAPE NEAR MOIST AXIS...BUT ALSO
INCREASING MLCINH LIKELY WITH EVENING DIABATIC COOLING NEAR SFC. 
THIS WILL MAKE DAMAGING WIND POTENTIAL MORE CONDITIONAL/MRGL WITH
TIME.  MEANWHILE NEARLY PARALLEL NATURE OF MEAN FLOW TO CONVECTIVE
PLUME SUPPORTS QUASI-LINEAR CONVECTIVE MODE...LIKELY LIMITING THREAT
FOR SIGNIFICANT SVR HAIL.  NONETHELESS...PRESENCE OF FAVORABLE
BUOYANCY ATOP MOISTURE PLUME...AND EFFECTIVE SHEAR MAGNITUDES
RANGING FROM AROUND 50 KT OVER NRN IL TO 35 KT NEAR MKC...WILL
SUPPORT SOME POTENTIAL FOR ORGANIZED CONVECTION WITH SPORADIC SVR. 
THREAT SHOULD DIMINISH SEWD OVER E-CENTRAL IL AND NRN INDIANA INTO
PROGRESSIVELY WEAKER LOW-LEVEL THETAE.

..EDWARDS.. 03/28/2012

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

ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX...TOP...

LAT...LON   39399540 42418725 41048727 38139546 39399540

Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Kansas, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.