MESO: Mesoscale Discussion 0016

ACUS11 KWNS 122145
SWOMCD
SPC MCD 122145
ILZ000-MOZ000-IAZ000-ARZ000-OKZ000-KSZ000-130315-

MESOSCALE DISCUSSION 0016
NWS STORM PREDICTION CENTER NORMAN OK
0345 PM CST SAT JAN 12 2013

AREAS AFFECTED...NERN OK...SERN KS...CNTRL MO...W-CNTRL IL

CONCERNING...WINTER MIXED PRECIPITATION

VALID 122145Z - 130315Z

SUMMARY...WINTER MIXED PRECIPITATION IS EXPECTED TO INCREASE LATE
THIS AFTERNOON AND EVENING FROM NERN OK NEWD INTO W-CNTRL IL AS
HEAVIER PRECIPITATION MOVES IN FROM THE SSW. LIQUID EQUIVALENT RATES
OF 0.05-0.15 IN/HR WILL BE POSSIBLE...MAINLY IN HEAVIER
SLEET/FREEZING RAIN BANDS.

DISCUSSION...AT 21Z...RADAR LOOP SHOWS A LARGE AREA OF RAIN WITH
EMBEDDED THUNDERSTORMS OVER ERN OK AND NWRN AR SPREADING TO THE
NORTHEAST. THIS ACTIVITY IS BEING DRIVEN BY ISENTROPIC LIFT OVER A
FRONTAL BOUNDARY THAT EXTENDS FROM NERN TX THROUGH CNTRL AR...WITH
SUFFICIENT MID-LEVEL LAPSE RATES FUELING ELEVATED CONVECTION.
MEANWHILE...THE FREEZING LINE CURRENTLY RUNS FROM A BVO-20 N JLN-IRK
LINE...WITH THE WET-BULB ZERO LINE RUNNING FROM ROUGHLY
TUL-JLN-COU-UIN. A COMBINATION OF EVAPORATIVE COOLING AND MODEST
LOW-LEVEL COLD ADVECTION SHOULD ALLOW THE FREEZING LINE TO MOVE
SOUTH WITH TIME AS HEAVIER PRECIPITATION OVERSPREADS THE REGION.

STRONG LOW-MID LEVEL FRONTOGENESIS IN THE 21-03Z TIMEFRAME SHOULD
MAINTAIN ASCENT OVER THE REGION THROUGH THE EVENING...WITH BANDING
AND POTENTIALLY SOME RESIDUAL UPRIGHT BUOYANCY MAINTAINING
OCCASIONALLY MODERATE/HEAVY PRECIP RATES. THE NRN PART OF THE MCD
AREA IS LIKELY TO CHANGEOVER FROM SLEET TO SNOW BY 00Z...WITH NARROW
TRANSITION ZONES OF SLEET AND FREEZING RAIN FROM NW TO SE SOUTH OF
THE SNOW AREA AS THE COLD AIRMASS GETS PROGRESSIVELY MORE SHALLOW.

..DEAN.. 01/12/2013

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

ATTN...WFO...ILX...LSX...DVN...SGF...EAX...TSA...TOP...ICT...
OUN...

LAT...LON 35249706 35689747 37249612 38519466 39289356 40079229
40499130 40499003 40108960 39399042 38269185 37619269
36189464 35249706

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.