328  
FXUS61 KILN 281938  
AFDILN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WILMINGTON OH  
338 PM EDT FRI APR 28 2017  
   
SYNOPSIS
 
 
SHOWERS AND THUNDERSTORMS ARE EXPECTED TONIGHT INTO SATURDAY AS  
A WARM FRONT LIFTS NORTH ACROSS THE OHIO VALLEY. A MUCH WARMER  
AIRMASS WILL BE IN PLACE ACROSS THE AREA THROUGH THE WEEKEND. A  
COLD FRONT WILL BRING ANOTHER CHANCE OF PRECIPITATION SUNDAY  
NIGHT INTO MONDAY AND USHER IN A COOLER AIRMASS FOR NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
 
 
LATEST SURFACE ANALYSIS IS SHOWING THE WARM FRONT STRETCHING  
FROM FAR SOUTHWEST KENTUCKY EASTWARD INTO SOUTHERN WEST  
VIRGINIA. ALONG AND SOUTH OF THIS BOUNDARY, SKIES HAVE BEEN  
MOSTLY CLEAR THROUGH MUCH OF THE DAY AND THIS HAS ALLOWED FOR  
SOME DECENT DESTABILIZATION WITH SURFACE BASED CAPES IN THE 1000  
TO LOCALLY 2000 J/KG RANGE ACROSS PARTS SOUTHERN KENTUCKY.  
FARTHER NORTH ACROSS OUR AREA, INSTABILITY IS MUCH MORE LIMITED  
SO FAR AS SKIES HAVE BEEN MOSTLY CLOUDY OVER ALL BUT OUR FAR  
SOUTHERN AREAS. THE FRONT IS FORECAST TO SHIFT SLOWLY NORTH  
THROUGH TONIGHT BUT THE NORTHWARD EXTENT REMAINS IN DOUBT AND  
WILL DICTATE BOTH THE SEVERE THREAT INTO THE EVENING AND THE  
POTENTIAL FOR FLASH FLOODING OVERNIGHT.  
 
THE HIS RES CAMS CONTINUE TO BOUNCE AROUND ON THE PLACEMENT/TRACK  
OF DEVELOPING CONVECTION CURRENTLY BACK ACROSS SOUTHEAST  
MISSOURI. THE HRRR HAS GENERALLY BEEN TRENDING SLIGHTLY FARTHER  
NORTH BUT OCCASIONAL RUNS HAVE REMAINED SOUTH OF OUR AREA.  
MEANWHILE, THE 12Z WRF-ARW IS FARTHER SOUTH WHILE THE NMM IS MUCH  
FARTHER NORTH. MEANWHILE, 12Z NSSL WRF IS MORE IN THE MIDDLE,  
AFFECTING MUCH OF OUR SOUTHERN FA. BASED ON THE POSITION OF THE  
FRONT ATTM, WOULD EXPECT TO SEE SOME ADDITIONAL DEVELOPMENT IN  
THE WARM SECTOR OVER THE NEXT COUPLE OF HOURS AS SOME WEAK MID  
LEVEL SHORT WAVE ENERGY BEGINS TO MOVE INTO THE LOWER OHIO  
VALLEY. IF THIS DEVELOPS, WOULD EXPECT THE BULK OF THIS TO TRACK  
ALONG OR JUST SOUTH OF OUR AREA AND CONTAIN THE HIGHEST SEVERE  
THREAT, AS THIS WILL BE ON THE INSTABILITY GRADIENT AND CLOSE  
TO THE AREA OF BETTER LOW LEVEL SHEAR ALONG THE BOUNDARY. IF  
THESE DO DEVELOP, THIS WOULD LEAD TO THE POTENTIAL FOR SOME  
ROTATING STORMS ACROSS OUR FAR SOUTHERN FA AS WE HEAD INTO THIS  
EVENING. FARTHER NORTH OF THE BOUNDARY, STORMS SHOULD BE MORE  
ELEVATED, LEADING TO A PRIMARY SEVERE THREAT OF HAIL.  
 
GOOD MOISTURE ADVECTION OVER THE FRONT WILL HELP PUSH PWS UP TO  
AROUND 2 INCHES TONIGHT. THE SYNOPTIC MODELS ARE FARTHER NORTH  
WITH THE BOUNDARY AND THUS WITH THE AXIS OF HEAVY RAIN OVERNIGHT  
TONIGHT. THIS LEADS TO QUITE A BIT OF UNCERTAINTY AS TO THE  
FLASH FLOOD POTENTIAL. FOR NOW, WILL LEAN TOWARD STICKING WITH  
THE CURRENT FFA, THINKING THAT THE BEST CHANCE FOR ANY FLASH  
FLOODING WOULD BE WITH POTENTIAL TRAINING STORMS ACROSS OUR  
SOUTHWEST HEADING INTO TONIGHT. HOWEVER, DEPENDING ON RADAR  
TRENDS, THIS MAY NEED TO BE ADJUSTED FARTHER NORTH AND/OR EAST  
AS THE EVENT BEGINS TO PLAY OUT.  
 

 
   
SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/
 
 
THE BOUNDARY WILL CONTINUE TO LIFT NORTHWARD THROUGH THE DAY ON  
SATURDAY. AS WE GET INTO THE WARM SECTOR, SOUTHERN PORTIONS OF  
OUR FA WILL PUSH WELL INTO THE 80S WITH GOOD INSTABILITY  
DEVELOPING AS WE HEAD THROUGH THE DAY. PCPN CHANCES WILL AGAIN  
BE DEPENDENT ON THE PLACEMENT AND TIMING OF THE FRONT, BUT GIVEN  
THE INSTABILITY, WILL ALLOW FOR CHANCE POPS TO SLOWLY LIFT  
NORTH ACROSS THE AREA WITH THE BOUNDARY THROUGH THE DAY. AS THE  
FRONT PUSHES OFF TO OUR NORTH, WE SHOULD SEE A DECREASING CHANCE  
OF PCPN ACROSS THE NORTH HEADING INTO SATURDAY NIGHT.  
 

 
   
LONG TERM /SUNDAY THROUGH FRIDAY/
 
 
AREA WILL BE IN THE WARM SECTOR ON SUNDAY WHICH WILL ALLOW  
TEMPERATURES TO BE VERY WARM WITH FORECAST HIGHS JUST A FEW DEGREES  
BELOW RECORDS. CANNOT RULE OUT A FEW STORMS DRIFTING INTO WESTERN  
COUNTIES, ALTHOUGH MOST ACTIVITY WILL BE WEST OF THE FORECAST AREA.  
 
OCCLUDED FRONT WILL SWEEP THROUGH THE REGION SUNDAY NIGHT INTO  
MONDAY. EXPECT A BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS TO TRACK  
ACROSS THE AREA WITH THIS FEATURE. INSTABILITY LOOKS WEAK AND  
PRECIPITATION WILL BE PROGRESSIVE, SO THREATS SEEMS TO BE QUITE  
LIMITED.  
 
CLOSED LOW WILL LIFT FROM THE MISSISSIPPI VALLEY INTO THE WESTERN  
GREAT LAKES MONDAY INTO TUESDAY BEFORE OPENING UP AND TRACKING EAST.  
ASSOCIATED SURFACE LOW WILL PASS NORTH OF THE AREA. BUT THERE WILL  
BE A STRONG GRADIENT SOUTH OF THE LOW. SO EXPECT GUSTY WINDS MONDAY  
INTO TUESDAY. A FEW SHOWERS COULD PASS ACROSS THE AREA MONDAY.  
 
HIGH PRESSURE WILL BRIEFLY BUILD IN LATER TUESDAY INTO TUESDAY  
NIGHT. BUT THE PRECIPITATION WILL ALREADY START TO SPREAD INTO  
SOUTHWEST COUNTIES ON WEDNESDAY AS A WARM FRONT DEVELOPS SOUTH OF  
THE AREA. THE FRONT WILL BECOME MORE PRONOUNCED UNTIL LOW PRESSURE  
MOVES THROUGH THE TENNESSEE VALLEY THURSDAY INTO THURSDAY NIGHT. SO  
THERE WILL BE A CHANCE OF SHOWERS DURING THIS TIME PERIOD. THE  
CHANCE OF RAIN WILL THEN DIMINISH ON FRIDAY.  
 
AFTER THE OCCLUDED FRONT MOVES THROUGH, TEMPERATURES WILL BE BELOW  
NORMAL.  
 

 
   
AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
 
 
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THROUGH THE  
LATE AFTERNOON AND INTO THE OVERNIGHT HOURS AS A WARM FRONT  
LIFTS NORTH INTO THE OHIO VALLEY. THERE REMAINS QUITE A BIT OF  
UNCERTAINTY AS TO THE TIMING AND PLACEMENT OF THESE STORMS  
THOUGH WHICH LEADS TO A LOW CONFIDENCE FORECAST, ESPECIALLY  
INTO TONIGHT. WILL TREND THE TAFS TOWARD THE GENERAL CONSENSUS  
OF THE HIGHER RES MODELS, ALLOWING FOR THUNDER AT THE TERMINALS  
MAINLY IN THE 23-03Z TIME FRAME, WITH THE BEST CHANCE AT THE  
SOUTHERN SITES. THIS WILL LEAD TO SOME MVFR VSBYS ALONG WITH  
THE POTENTIAL FOR IFR OR LOWER IN ANY THUNDERSTORMS, AS LOCALLY  
HEAVY RAINFALL WILL BE POSSIBLE. CIGS WILL START OFF VFR BUT  
SHOULD TREND TO MVFR AS THE LOW LEVELS MOISTEN UP OVERNIGHT,  
ESPECIALLY ALONG AND NORTH OF THE BOUNDARY. MVFR CIGS WILL THEN  
LIKELY LINGER THROUGH THE MORNING HOURS ALONG AND NORTH OF THE  
BOUNDARY, MAINLY AFFECTING THE NORTHERN TAF SITES. THE THREAT  
FOR SHOWERS WILL PERSIST THROUGH MUCH OF THE NIGHT AND POSSIBLY  
INTO SATURDAY MORNING, BUT THIS WILL BE SOMEWHAT DEPENDENT ON  
THE EXACT PLACEMENT OF THE FRONTAL BOUNDARY.  
 
OUTLOOK...MVFR CEILINGS AND VISIBILITIES WITH A CHANCE OF THUNDERSTORMS  
ARE POSSIBLE SATURDAY, SUNDAY NIGHT AND MONDAY. WIND GUSTS TO 35  
KT POSSIBLE SUNDAY INTO TUESDAY.  
 

 
   
ILN WATCHES/WARNINGS/ADVISORIES
 
 
OH...FLASH FLOOD WATCH FROM 7 PM EDT THIS EVENING THROUGH SATURDAY  
MORNING FOR OHZ070>072-077>081.  
KY...FLASH FLOOD WATCH FROM 7 PM EDT THIS EVENING THROUGH SATURDAY  
MORNING FOR KYZ089>099.  
IN...FLASH FLOOD WATCH FROM 7 PM EDT THIS EVENING THROUGH SATURDAY  
MORNING FOR INZ066-073>075-080.  
 

 
 

 
SYNOPSIS...JGL  
NEAR TERM...JGL  
SHORT TERM...JGL  
LONG TERM...  
AVIATION...JGL  
 
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