• Mesodiscussion 0011 for 2013

Mesodiscussion 0011




MESOSCALE DISCUSSION 0011
NWS STORM PREDICTION CENTER NORMAN OK
0623 PM CST THU JAN 10 2013

AREAS AFFECTED...NRN WI...UPPER PENINSULA OF MI

CONCERNING...FREEZING RAIN 

VALID 110023Z - 110630Z

SUMMARY...FREEZING RAIN WILL AFFECT THE AREA WITH RATES OF AROUND
0.05 IN/HR...LOCALLY HIGHER...BETWEEN 02Z AND 08Z.

DISCUSSION...A 90-150-MILE WIDE...WNW/ESE-ORIENTED PRECIPITATION
SHIELD WILL CONTINUE ADVANCING NNEWD ACROSS PARTS OF NRN WI THIS
EVENING...ENTERING THE UPPER PENINSULA OF MI BY 04Z. THIS ACTIVITY
ACCOMPANIES A ZONE OF ELEVATED WAA/ISENTROPIC ASCENT -- REF. GRB VWP
DATA THAT DEPICT A VERTICALLY VEERING WIND PROFILE BELOW 1 KM AGL.
WITH FORECAST SOUNDINGS INDICATING ELEVATED WARM LAYER TEMPERATURES
RISING TO 3-6C IN ASSOCIATION WITH THE WARM ADVECTION...COMPLETE
MELTING OF DESCENDING HYDROMETEORS WILL OCCUR.

AT THE SFC...ESELY/SELY TRAJECTORIES...EMANATING FROM A CONTINENTAL
POLAR AIR MASS CENTERED OVER THE ERN GREAT LAKES REGION...WILL ALLOW
SFC WET BULB TEMPERATURES TO GENERALLY HOLD IN THE 30-32F RANGE.
THIS WILL BE AIDED BY NOCTURNALLY DRIVEN SFC-LAYER DIABATIC COOLING.
AS SUCH...FREEZING RAIN IS ANTICIPATED...WITH RATES OF 0.05 IN/HR
LIKELY...AND LOCALLY HIGHER RATES WILL BE POSSIBLE. THE MOST LIKELY
TIME FOR THE HIGHEST FREEZING RAIN RATES WILL BE FROM 02Z TO 08Z AS
THE PRECIPITATION SHIELD MOVES ACROSS THE REGION...WITH THE ACTIVITY
LIKELY TAPERING OFF LATER IN THE NIGHT. PRECIPITATION MAY LOCALLY
CHANGE TO RAIN WHERE SFC TEMPERATURES RISE ABOVE 32F...OWING TO
DOWNWARD-DIRECTED SENSIBLE HEAT FLUXES AND/OR VERY MODEST SFC WARM
ADVECTION.

..COHEN.. 01/11/2013

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

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON   46848904 46848827 46268766 45238828 44718948 44729106
            44979190 45199237 45539264 45769266 46299234 46659181
            46709116 46559055 46788966 46848904