MESO: Mesoscale Discussion 1224

ACUS11 KWNS 192157
SWOMCD
SPC MCD 192156
MNZ000-SDZ000-NDZ000-NEZ000-192330-

MESOSCALE DISCUSSION 1224
NWS STORM PREDICTION CENTER NORMAN OK
0456 PM CDT TUE JUN 19 2012

AREAS AFFECTED...PARTS OF NERN NEB...ERN SD...SERN ND INTO CNTRL MN

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 192156Z - 192330Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...UNCERTAINTY LINGERS CONCERNING TIMING OF BOUNDARY LAYER
BASED WARM SECTOR DEVELOPMENT...AND INITIATION OF MORE VIGOROUS
CONVECTION WITHIN LOWER/MID TROPOSPHERIC WARM ADVECTION TO THE NORTH
OF THE WARM FRONT. HOWEVER...ONE OR MORE WATCHES LIKELY WILL BE
NEEDED BY EARLY EVENING...PERHAPS WITHIN THE NEXT HOUR OR TWO.

DISCUSSION...VERY WARM ELEVATED MIXED LAYER AIR CONTINUES TO PROVIDE
STRONG INHIBITION TO CONVECTIVE DEVELOPMENT...BOTH IN THE WARM
SECTOR OF THE DEEP EASTERN SOUTH DAKOTA CYCLONE...AND WITHIN AT
LEAST A NARROW CORRIDOR TO THE NORTH OF THE WARM FRONT EXTENDING TO
THE EAST NORTHEAST...ACROSS PARTS OF CENTRAL MINNESOTA. THE VERY
MOIST WARM SECTOR HAS BECOME MODERATE TO STRONGLY UNSTABLE BENEATH
STEEP MID-LEVEL LAPSE RATES...WITH MIXED LAYER CAPE NOW ON THE ORDER
OF 2000-3000+ J/KG. AND DEEP LAYER SHEAR IS STRONG AND FAVORABLE
FOR SUPERCELLS...WITH LOW-LEVEL HODOGRAPHS SIZABLE AND SUPPORTIVE OF
TORNADIC POTENTIAL...MAINLY ALONG THE WARM FRONT.

LOW-LEVEL CONVERGENCE APPEARS MAXIMIZED NEAR THE SURFACE LOW...FROM
HURON INTO THE WATERTOWN AREA...AND DEEPENING CONVECTION IS ALREADY
EVIDENT TO THE NORTH OF HURON. GUIDANCE IS ALSO SUGGESTIVE THAT A
WEAKNESS IN THE INHIBITION MAY EXIST ACROSS THIS
VICINITY...SOUTHWARD ALONG A PRE-FRONTAL SURFACE TROUGH INTO
NORTHEAST NEBRASKA...ALONG WHICH SHALLOWER CUMULUS DEVELOPMENT HAS
BEEN EVIDENT. MEANWHILE...AN INCREASE IN STORM DEVELOPMENT DOES
APPEAR UNDERWAY TO THE NORTH OF THE WARM FRONT...ACROSS PARTS OF
SOUTHEASTERN NORTH DAKOTA INTO WEST CENTRAL MINNESOTA...WHICH THE
LATEST HIGH RESOLUTION RAPID REFRESH SUGGESTS MAY EXPAND
CONSIDERABLY AND GROW UPSCALE THROUGH THE 00-02Z TIME FRAME.

WHILE THE EVOLUTION OF CONVECTIVE DEVELOPMENT DURING THE NEXT FEW
HOURS REMAINS A BIT UNCLEAR...THE GREATEST SEVERE WEATHER
POTENTIAL...INCLUDING THE RISK FOR TORNADOES...APPEARS TO EXIST WITH
CONVECTION NEAR THE HURON/WATERTOWN AREAS...IF AND WHEN THE CAP
FINALLY BREAKS LATE THIS AFTERNOON.

..KERR/KERR.. 06/19/2012

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

ATTN...WFO...DLH...MPX...FGF...FSD...ABR...BIS...LBF...

LAT...LON 45829878 46519772 46869632 47059514 46849402 46289359
45509412 45029591 43809733 42889823 42909905 44209843
44779874 45389902 45829878

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.