MESO: Mesoscale Discussion 2041

ACUS11 KWNS 130320
SWOMCD
SPC MCD 130319
MNZ000-IAZ000-NEZ000-130745-

MESOSCALE DISCUSSION 2041
NWS STORM PREDICTION CENTER NORMAN OK
0919 PM CST FRI NOV 12 2010

AREAS AFFECTED...WESTERN/NORTHERN IA TO SOUTH-CENTRAL MN

CONCERNING...HEAVY SNOW

VALID 130319Z - 130745Z

A CHANGEOVER TO MODERATE/HEAVY WET SNOW IS EXPECTED THE REMAINDER OF
THE EVENING/OVERNIGHT WITHIN A SOUTHWEST-NORTHEAST CORRIDOR ACROSS
WESTERN/NORTHERN IA TO SOUTH-CENTRAL MN.

IT IS LIKELY THAT PRECIPITATION WILL CONTINUE TO EXPAND/ORIENT INTO
GENERAL SOUTHWEST-NORTHEAST BANDS THE REMAINDER OF THE NIGHT WITHIN
AN EVOLVING DEFORMATION BAND/LOW LEVEL BAROCLINIC ZONE FROM FAR
EASTERN NEB TO WESTERN/NORTHERN IA AND SOUTHERN MN. SURFACE WET BULB
TEMPERATURES REMAIN AROUND/JUST ABOVE FREEZING IN MOST LOCALES AT
MID EVENING /03Z/...BUT COLD ADVECTION/HIGH PRECIPITATION RATES WILL
CONTINUE TO RESULT IN A CHANGEOVER TO /OR AT LEAST EMBEDDED BOUTS
OF/ SNOW.

IN ACCORDANCE WITH THE 00Z OMAHA OBSERVED RAOB AND OBSERVED SURFACE
OBSERVATIONAL TRENDS...RUC/00Z NAM SOUNDINGS SUPPORT THE IDEA OF A
CHANGEOVER TO MODERATE/HEAVY WET SNOW THE REMAINDER OF THE NIGHT
WITHIN THIS CORRIDOR...WITH A SATURATED DENDRITIC GROWTH LAYER ATOP
A DEEP /JUST BELOW FREEZING/ ISOTHERMAL LAYER BEING RATHER FAVORABLE
FOR LARGE FLAKES/AGGREGATE SNOW GROWTH ESPECIALLY TOWARD THE 06Z-09Z
TIME FRAME AND BEYOND. FURTHERMORE...WITH RELATIVELY WEAK STATIC
STABILITY/STEEP LAPSE RATES ALOFT /AND EVEN SOME SCANT CAPE NOTED IN
SOME FORECAST SOUNDINGS/...EMBEDDED SNOW RATES MAY APPROACH OR
EXCEED 1 IN/HR ON A LOCALIZED BASIS.

..GUYER.. 11/13/2010

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

ATTN...WFO...ARX...MPX...DMX...FSD...OAX...

LAT...LON 44539438 44089282 42689443 41509536 42389641 44539438

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