SPC MD 105

MD 0105 CONCERNING HEAVY SNOW FOR CNTRL/ERN NEB...N-CNTRL KS
MESOSCALE DISCUSSION 0105 NWS STORM PREDICTION CENTER NORMAN OK 0636 PM CST FRI FEB 03 2012 AREAS AFFECTED...CNTRL/ERN NEB...N-CNTRL KS CONCERNING...HEAVY SNOW VALID 040036Z - 040430Z SNOWFALL RATES OF 1 INCH PER HOUR /LOCALLY HIGHER/ ARE ANTICIPATED ACROSS A LARGE PART OF CNTRL/ERN NEB AND N-CNTRL KS DURING THE EVENING AND OVERNIGHT HOURS. ONGOING MODERATE TO LOCALLY HEAVY SNOW WILL CONTINUE INTO MID-EVENING ALONG AND NORTH OF A LINE FROM NORTH PLATTE TO NORFOLK. THIS SNOW WILL BE MAINTAINED WITH THE PLUME OF MOIST ASCENT OWING TO WAA EMBEDDED WITHIN A BRANCH OF THE WARM CONVEYOR BELT WRAPPING AROUND A MID-LEVEL VORT MAX POSITIONED OVER NWRN KS. SNOWFALL RATES MAY LOCALLY REACH 1 IN/HR IN A FEW LOCATIONS...MAINLY FROM LOGAN COUNTY ENEWD INTO LOUP COUNTY...WHERE REGIONAL RADAR IMAGERY DEPICTS A BAND OF PERSISTENTLY ENHANCED REFLECTIVITY. ALSO...NNELY WINDS OF 15-25 MPH MAY RESULT IN BLOWING/DRIFTING SNOW. AFTER 03Z...THE THREAT FOR HEAVY SNOW...WITH RATES LIKELY REACHING /AND LOCALLY EXCEEDING/ 1 IN/HR...WILL REFOCUS TO THE SOUTH...WHILE DEVELOPING NWD FROM N-CNTRL KS INTO CNTRL AND ERN NEB. THESE RATES WILL CONTINUE INTO THE OVERNIGHT HOURS. ASCENT FOR THIS LATTER ACTIVITY WILL EMANATE FROM A ZONE OF INCREASING DCVA LEADING THE AFOREMENTIONED VORT MAX...ENHANCED BY THE ASCENDING BRANCH OF THE AGEOSTROPHIC CIRCULATION WITHIN LEFT-EXIT REGION OF AN UPPER-LEVEL JET STREAK CROSSING THE AREA. WHILE INITIALLY SOMEWHAT WARM...THERMODYNAMIC PROFILES WILL BECOME INCREASINGLY CONDUCIVE FOR A PHASE CHANGE FROM RAIN TO SNOW DURING THE EVENING HOURS IN RESPONSE TO /1/ STRONG ADIABATIC COOLING OWING TO THE FORCED ASCENT.../2/ NOCTURNAL DIABATIC COOLING...AND /3/ LOW-LEVEL COLD ADVECTION ON THE BACKSIDE OF A NEWD-MIGRATING SFC LOW ACROSS OK/KS. ACROSS S-CNTRL NEB INTO N-CNTRL KS...RUC/NAM FORECAST SOUNDINGS INDICATE THE DEVELOPMENT OF A SHALLOW LAYER OF VERY MARGINAL BUOYANCY ROOTED BETWEEN 550 AND 600 MB /MUCAPE VALUES GENERALLY AOB 100 J PER KG/ ATOP A NEARLY ISOTHERMAL LAYER JUST BELOW FREEZING WITHIN THE LOW/MID LEVELS. IN ADDITION TO FAVORING SNOW AGGREGATION PROCESSES...THIS PROFILE MAY SUPPORT A LIGHTNING STRIKE OR TWO ALONG WITH LOCALLY HIGHER SNOWFALL RATES AROUND 1.5 IN/HR. ..COHEN.. 02/04/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FSD...OAX...TOP...GID...LBF...GLD... LAT...LON 41459607 40809619 40109680 39399815 39189973 39620081 40720147 41760116 42659895 42369662 41459607 Read more

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