323  
ACUS11 KWNS 071028  
SWOMCD  
SPC MCD 071028  
NYZ000-PAZ000-MDZ000-WVZ000-VAZ000-OHZ000-071530-  
 
MESOSCALE DISCUSSION 0056  
NWS STORM PREDICTION CENTER NORMAN OK  
0428 AM CST WED FEB 07 2018  
 
AREAS AFFECTED...EASTERN WV...MUCH OF PA...NORTHEAST OH...AND  
WESTERN INTO CENTRAL NY  
 
CONCERNING...WINTER MIXED PRECIPITATION  
 
VALID 071028Z - 071530Z  
 
SUMMARY...HEAVIER RATES OF WINTER PRECIPITATION ARE FORECAST ACROSS  
THE DISCUSSION AREA. ONE INCH PER HOUR SNOWFALL RATES ARE EXPECTED  
FROM NORTHEAST OH THROUGH NORTHERN PA AND INTO NY. FREEZING RAIN  
RATES AT OR ABOVE 0.05 INCH PER HOUR ARE EXPECTED FROM EASTERN WV  
INTO SOUTH-CENTRAL PA.  
 
DISCUSSION...RADAR MOSAIC SHOWS AN EXTENSIVE PRECIPITATION SHIELD  
FROM THE TN VALLEY NORTHEAST THROUGH THE UPPER OH VALLEY EARLY THIS  
MORNING. SURFACE ANALYSIS INDICATES TEMPERATURES ARE BELOW FREEZING  
FROM NEAR THE OH RIVER NORTHEAST THROUGH SOUTHWEST PA, EASTERN WV,  
AND EAST TOWARDS THE NORTH PART OF THE CHESAPEAKE BAY. 88D VAD DATA  
SHOW STRONG AND VEERING FLOW WITH HEIGHT --IMPLYING STRONG LOW-LEVEL  
WARM-AIR-ADVECTION PROCESS-- CONCURRENT WITH THE NORTHEASTWARD  
MOVEMENT OF THE PRECIPITATION SHIELD AND SATURATION OF THE LOW-LEVEL  
PROFILE WITH TIME OVER PA, AND IN TIME, OVER NY.  
 
FORECAST SOUNDINGS OF THE AREA SUGGEST THE THERMAL PROFILE WILL  
SUPPORT SNOW FROM NORTHEAST OH THROUGH NORTHERN PORTIONS OF PA AND  
INTO NY. GENERALLY STEADY RATES AROUND 1 INCH PER HOUR ARE FORECAST  
FOR SEVERAL HOURS ON THE NORTHERN PORTION OF THE EVOLVING  
PRECIPITATION PLUME. FARTHER SOUTH, A WARM LAYER ABOVE A  
SUB-FREEZING NEAR-SURFACE LAYER WILL FAVOR MIXED PRECIPITATION,  
PRIMARILY IN THE FORM OF FREEZING RAIN. RATES AT OR ABOVE 0.05 INCH  
PER 3 HOURS ARE EXPECTED PER MODEL GUIDANCE AS THE PROFILE CONTINUES  
TO MOISTEN. DURING THE MID-LATE MORNING HOURS, A GRADUAL TRANSITION  
OF FREEZING RAIN TO RAIN IS EXPECTED TO OCCUR FROM SOUTH TO NORTH AS  
SURFACE TEMPERATURES WARM ABOVE FREEZING.  
 
..SMITH.. 02/07/2018  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ALY...PHI...BGM...BUF...CTP...LWX...PBZ...CLE...  
 
LAT...LON 42267468 40357571 39007923 40298007 40868225 41628180  
43677578 43527430 42267468  
 
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