166  
AWUS01 KWNH 271802  
FFGMPD  
VAZ000-WVZ000-OHZ000-KYZ000-272300-  
 
MESOSCALE PRECIPITATION DISCUSSION 0575  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
201 PM EDT THU JUL 27 2017  
 
AREAS AFFECTED...SOUTEHERN WV...EASTERN KY...EXT SOUTHERN  
OH...SOUTHWEST VA  
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
 
VALID 271800Z - 272300Z  
 
SUMMARY...FEW ROUNDS OF HEAVY RAIN POSE FLASH FLOODING THREAT  
THROUGH EVENING ACROSS FOOTHILLS AND CENTRAL APPALACHIANS.  
 
DISCUSSION...EXP. GOES-16 CONUS IMAGERY SUITE DEPICTS A SMALL  
SHORTWAVE AT THE FAR EASTERN EXTENSION OF WARM CONVEYOR BELT WHERE  
LOW LEVEL FLOW EVEN HAS FLATTENED TO DUE WESTERLY SUPPORTING A  
STRONG LINE OF CONVECTION CROSSING THE CENTRAL APPALACHIANS. THIS  
LOW LEVEL WESTERLY FLOW PROVIDES STRONG MST TRANSPORT INTO THE  
REAR OF THE CONVECTIVE LINE ALLOWING FOR SOLID CONVERGENCE ATTM.  
 
AREA OF CONCERN IS ALSO AT THE EASTERN PERIPHERY OF FAVORABLE  
UPPER LEVEL DIFFLUENCE FROM WNW 3H JET AND MODEST INSTABILITY AND  
TPWS UP TO 2.0" THERE HAS BEEN INCREASING EFFICIENCY TO CELLS ON  
THE LINE. RAIN RATES ARE ON AVERAGE 2.0"/HR THOUGH FORWARD  
PROGRESS OF THE LINE HAS BEEN LIMITING TOTALS BASED ON OBSERVATION  
NETWORK TO AT MOST 1.8"/HR AND 2.07" TOTAL AT KERMIT IFLOWS GAUGE  
WITH NUMEROUS OTHER SITES IN THE 1.5" RANGE. THIS IS JUST AT THE  
CUSP OF LOCAL FFG VALUES AND IS NOT LIKELY TO EXCEED AS THE LINE  
ROLLS INTO SW VA IN THE NEXT FEW HOURS. HOWEVER...THIS IS ONLY  
PRIMING THE AREA FOR POTENTIAL FLASH FLOODING WITH THE NEXT BOUT.  
 
WEAK DPVA ALONG SE FLANK OF MID-LEVEL SHORTWAVE SEEN IN WV/VISIBLE  
IMAGERY OVER N CENTRAL OHIO AND STRONG UPPER LEVEL FLOW AND  
ACCOMPANYING DIFFLUENCE ALLOW FOR A FAVORABLE REGION FOR UPSTREAM  
DEVELOPMENT OVER S OH/E KY OVER THE NEXT FEW HOURS. FILTERED  
SOLAR INSOLATION HAS ALLOWED SURFACE TEMPS TO REBOUND TO THE  
MID-UPPER 80S ACROSS CENTRAL KY WITH TDS IN THE LOW TO MID 70S  
SUPPORTING SBCAPES TO 2500 J/KG. WHILE MST FLUX IS A BIT LESSENED  
THAN FURTHER EAST THERE IS SUFFICIENT MOISTURE TO SUPPORT ANOTHER  
CONVECTIVE LINE CAPABLE OF 1.5-2"/HR RATES.  
 
RAPID REFRESH HI-RES CAMS SUCH AS THE HRRR AND ESRL HRRRV3 SUGGEST  
THE LINE TO DEVELOP IN THE NEXT 1-2 HOURS THOUGH RECENT IR/VIS  
TRENDS INDICATE CONVECTIVE INITIATION HAS TAKEN PLACE ACROSS LEWIS  
COUNTY KY WITH OTHER TOWERS FURTHER SW IN THE INSTABILITY AXIS.  
EXPECT HRRR/HRRRX SOLUTIONS TO LAG IN TIME BUT EVOLVE PROPERLY  
WITH AN ADDITIONAL 2-3" TOTALS EXPECTED. THIS SHORTENS THE TIME  
FROM THE FIRST BOUT...SUGGESTING FLASH FLOODING MAY BE POSSIBLE  
GIVEN WATER IN THE SYSTEM.  
 
GALLINA  
   
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ILN...JKL...MRX...RLX...RNK...  
 
ATTN...RFC...LMRFC...MARFC...OHRFC...SERFC...  
 
LAT...LON 39188271 38998169 38297992 37597900 36697934  
36678185 36728389 37738375 38428369  
 
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