441  
FXUS61 KILN 141033  
AFDILN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE WILMINGTON OH  
633 AM EDT FRI MAY 14 2021  
   
SYNOPSIS
 
 
HIGH PRESSURE AND DRY CONDITIONS WILL PREVAIL ACROSS THE REGION  
TODAY INTO SATURDAY. A FRONTAL BOUNDARY WILL MOVE INTO THE OHIO  
VALLEY SUNDAY INTO MONDAY, BRINGING A CHANCE OF SHOWERS TO THE  
REGION THROUGH THE EARLY PART OF THE UPCOMING WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
SURFACE HIGH PRESSURE IS IN PLACE ACROSS THE REGION THIS  
MORNING. WHILE OUR AREA IS GENERALLY CLEAR THIS MORNING, THERE  
IS SOME VERY WEAK MID LEVEL TROUGHING OVERHEAD WITHIN THE  
BROADER RIDGE ALOFT AND THIS COULD RESULT IN SOME SPOTTY MID  
LEVEL CLOUDS THROUGH MID MORNING. EXPECT ANY MID LEVEL CLOUDS  
TO DISSIPATE/EVAPORATE AWAY THOUGH AS WE PROGRESS THROUGH LATE  
MORNING. WE SHOULD THEN SEE A FEW DIURNAL CU DEVELOP AGAIN AS  
WE HEAD INTO THIS AFTERNOON. TEMPERATURES WILL CONTINUE TO  
SLOWLY MODERATE WITH HIGHS TODAY IN THE UPPER 60S TO AROUND 70  
DEGREES.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
 
 
THE SURFACE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST/SOUTHEAST  
TONIGHT INTO SATURDAY AS SOME MID LEVEL ENERGY SPREADS IN FROM  
THE WEST. THE AIRMASS ACROSS OUR AREA WILL REMAIN ON THE DRY  
SIDE THROUGH THROUGH THE DAY ON SATURDAY SO GENERALLY JUST  
EXPECT TO SEE AN INCREASE IN SOME MID AND HIGHER LEVEL CLOUDS.  
THE GRADUAL WARMING TREND WILL CONTINUE WITH LOWS TONIGHT IN THE  
MID 40S AND HIGHS ON SATURDAY IN THE LOWER 70S.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
 
 
ON SATURDAY NIGHT, A GENERALLY WEAK SURFACE PRESSURE PATTERN WILL BE  
IN PLACE ACROSS THE EASTERN HALF OF THE CONUS, WITH HIGH PRESSURE  
OFF THE EAST COAST. LOOKING FURTHER ALOFT, THERE WILL ALREADY BE  
SOME CHANGES OCCURRING WITH THE WEATHER PATTERN. RIDGING OVER THE  
SOUTHEASTERN STATES WILL COMBINE WITH A SHORTWAVE MOVING INTO THE  
GREAT LAKES TO PROVIDE A GENERAL FEED OF MOISTURE FROM THE WESTERN  
GULF COAST THROUGH THE MIDDLE MISSISSIPPI VALLEY, AND EVENTUALLY  
INTO THE OHIO VALLEY. THETA-E ADVECTION IN THE 925MB-850MB LAYER IS  
EXPECTED TO INCREASE OVER THE ILN FORECAST AREA LATE SATURDAY NIGHT  
INTO SUNDAY MORNING, WITH THIS DEVELOPING WARM FRONT ACTING AS A  
FOCUS FOR SCATTERED PRECIPITATION EARLY SUNDAY. THIS FRONT WILL NOT  
BE MOVING TOO QUICKLY -- AND IN FACT, RECENT MODEL RUNS CONTINUE THE  
TREND OF LARGELY STALLING IT OVER THE SOUTHERN PARTS OF THE ILN CWA  
ON SUNDAY AND INTO MONDAY. ANY WEAK DISTURBANCES IN THE MID-LEVEL  
FLOW WILL LIKELY HELP TO KICK OFF SHOWERS ATOP THIS LOW-LEVEL  
FRONTAL ZONE, BUT OVERALL POPS WILL BE LIMITED TO THE CHANCE  
CATEGORY THROUGH THE DAYTIME HOURS ON SUNDAY, WITH GENERALLY WEAK  
BOUNDARY LAYER FORCING. WITH CLOUDS AND PRECIPITATION, AND  
SOUTHEASTERLY SURFACE WINDS, MAX TEMPS WILL LIKELY ONLY REACH THE  
MIDDLE TO UPPER 60S -- SLIGHTLY LOWER THAN SATURDAY.  
 
THE FORECAST FOR MONDAY REMAINS SOMEWHAT COMPLICATED, AS ANOTHER  
SHORTWAVE MOVES INTO THE AREA ATOP THE FRONTAL ZONE. STILL SEEING  
SOME DIFFERENCES BETWEEN MODELS ON JUST HOW FAR NORTH THE FRONT WILL  
GET, IF IT WILL EVEN MOVE MUCH AT ALL. IT DOES APPEAR THAT  
PRECIPITATION IS LIKELY DURING THE DAY ON MONDAY, WITH SOME THUNDER  
ALSO POSSIBLE (PARTICULARLY FURTHER SOUTH). FIGURING OUT THE  
PLACEMENT OF THE HEAVIEST RAIN (PERHAPS OVER AN INCH) IS SOMETHING  
THAT WILL HAVE TO BE REFINED IN FUTURE FORECAST UPDATES. WOULD  
PREFER NOT TO INCLUDE A HUGE JUMP IN TEMPERATURES FROM SUNDAY TO  
MONDAY, BUT A SLIGHTLY MODIFIED AIR MASS SHOULD ALLOW FOR MAX TEMPS  
NEAR 70. A GRADUAL DIMINISHING TREND IN FORCING (AND PRECIPITATION  
CHANCES) IS EXPECTED LATER MONDAY NIGHT INTO TUESDAY.  
 
WHILE FORECAST UNCERTAINTY INCREASES FROM TUESDAY AND BEYOND, THERE  
SEEMS TO BE GENERAL AGREEMENT IN AN AMPLIFYING PATTERN, WITH THE  
OHIO VALLEY LIKELY TO BE CAUGHT AT LEAST SOMEWHAT IN THE MIDDLE OF  
THE UPSTREAM TROUGH AND DOWNSTREAM RIDGE. THIS SUPPORTS INCREASING  
WARMTH / MOISTURE / INSTABILITY FOR THE SECOND HALF OF THE WEEK. BY  
WEDNESDAY AND THURSDAY, BOTH THE GFS AND ECMWF SHOW A LARGELY  
MERIDIONAL FLOW PATTERN OVER THE MIDDLE OHIO VALLEY REGION. THIS  
FORECAST WILL CONTINUE TO CARRY LOW-END POPS EACH DAY ON TUESDAY,  
WEDNESDAY, AND THURSDAY. THIS FORECAST WILL ALSO CARRY WARMING  
TEMPERATURES EACH DAY, WITH HIGHS LIKELY TO REACH THE UPPER 70S ON  
THURSDAY IF CLOUDS AND PRECIPITATION DO NOT ADVERSELY AFFECT  
INSOLATION.  
 

 
   
AVIATION /12Z FRIDAY THROUGH TUESDAY/
 
 
SURFACE HIGH PRESSURE WILL SHIFT SLOWLY SOUTHEAST ACROSS THE  
REGION TODAY INTO SATURDAY. SOME PATCHY RIVER VALLEY FOG HAS  
DEVELOPED AGAIN THIS MORNING AND THIS MAY BRIEFLY AFFECT KLUK  
NEAR THE START OF THE TAF PERIOD BEFORE DISSIPATING. OTHERWISE,  
EXPECTED A FEW DIURNAL CU LATER THIS MORNING INTO THIS  
AFTERNOON. ANY CU WILL DISSIPATE TOWARD SUNSET WITH MOSTLY  
CLEAR SKIES EXPECTED OVERNIGHT.  
   
OUTLOOK
 
MVFR CEILINGS POSSIBLE SUNDAY THROUGH TUESDAY.  
 

 
   
ILN WATCHES/WARNINGS/ADVISORIES
 
 
OH...NONE.  
KY...NONE.  
IN...NONE.  
 

 
 

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