MESO: Mesoscale Discussion 2159

ACUS11 KWNS 151524
SWOMCD
SPC MCD 151524
MNZ000-151930-

MESOSCALE DISCUSSION 2159
NWS STORM PREDICTION CENTER NORMAN OK
0924 AM CST SAT DEC 15 2012

AREAS AFFECTED...N CNTRL MN

CONCERNING...FREEZING RAIN

VALID 151524Z - 151930Z

SUMMARY...A TRANSIENT FREEZING RAIN THREAT WILL SUPPORT VERY
LOCALIZED/BRIEF FREEZING RAINFALL RATES OF 0.02 TO 0.04 INCH AN
HOUR. A PHASE CHANGE TO RAIN AND THEN SNOW WILL OCCUR LATER THIS
MORNING AND THROUGH THE AFTERNOON.

DISCUSSION...12Z ABR AND MSX SOUNDINGS REFLECT A WARM LAYER JUST
ABOVE THE SURFACE TO NEAR 700 MB. GIVEN THE PRESENCE OF SUBFREEZING
SURFACE TEMPERATURES...A NARROW CORRIDOR OF FREEZING RAIN HAS
DEVELOPED WITHIN A DEFORMATION ZONE. ALTHOUGH ONLY A FEW OBS ARE
REPORTING FZRA...RATES HAVE APPROACHED 0.04 INCHES AT TIMES /PER
PARK RAPIDS MN 1436Z OB/. A SUBTLE RISE IN SURFACE TEMPERATURES
OWING TO DIURNAL HEATING AND VERY WEAK WARM ADVECTION SHOULD ALLOW A
BRIEF PHASE CHANGE TO RAIN. THEREAFTER...THE UPPER/SURFACE LOW
LOCATED NEAR ERN NEB/WRN IA AS OF 15Z WILL TRACK NEWD...WITH COLD
AIR ADVECTION IN ITS WAKE SUPPORTING THE DEVELOPMENT OF LIGHT TO
MODERATE SNOW ACROSS MN LATER THIS MORNING THROUGH THE AFTERNOON.

..DISPIGNA.. 12/15/2012

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

ATTN...WFO...DLH...FGF...

LAT...LON 47469524 47959436 48039346 48099284 47919266 47719275
47199313 47029391 46989502 47469524

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