162  
FXUS61 KCLE 151341  
AFDCLE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CLEVELAND OH  
941 AM EDT WED AUG 15 2018  
   
..MID MORNING NEAR TERM FORECAST UPDATE
 
 
   
SYNOPSIS
 
 
HIGH PRESSURE OVER THE CENTRAL APPALACHIANS WILL MOVE SOUTHEAST  
AS A LOW PRESSURE SYSTEM MOVES FROM THE CENTRAL PLAINS CLOSER  
TO THE GREAT LAKES REGION TODAY. A WARM FRONT WILL MOVE OVER THE  
AREA TONIGHT. LOW PRESSURE WILL MOVE NORTH OF LAKE ERIE ON  
THURSDAY NIGHT INTO FRIDAY AND EXTEND A COLD FRONT ACROSS THE  
AREA ON FRIDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH  
FOR THE WEEKEND.  
 

 
   
NEAR TERM /THROUGH THURSDAY/
 
 
THERE ARE NO CHANGES TO THIS MID MORNING FORECAST UPDATE. THE  
FORECAST LOOKS ON TRACK. WE WILL SEE A SLOW INCREASE OF CLOUDS  
THROUGHOUT THE DAY AS THE NEXT STORM SYSTEM APPROACHES FROM THE  
WEST.  
 
PREVIOUS DISCUSSION...  
HIGH PRESSURE SOUTHEAST OF THE AREA WILL CONTINUE SOUTHEAST AS  
A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS MOVES CLOSER TO  
THE AREA. A WARM FRONT EXTENDING FROM THE LOW WILL APPROACH THE  
AREA LATER TODAY AND BRING A CHANCE FOR SHOWERS AND  
THUNDERSTORMS ACROSS THE REGION. THE TIMING OF THE WARM FRONT IS  
A BIT SLOWER FROM THE PREVIOUS MODEL RUNS SO HAVE CUT BACK RAIN  
CHANCES FOR THIS AFTERNOON TO A LOW CHANCE OUT WEST. HOWEVER,  
ONCE THE FRONT REACHES THE AREA TONIGHT, EXPECTING WIDESPREAD  
SHOWERS AND THUNDERSTORMS THROUGH THURSDAY. HAVE INTRODUCED  
CATEGORICAL POPS TO THE FORECAST, AS THERE CONTINUES TO BE  
DECENT FORCING WITH THE FRONT AND PLENTY OF MOISTURE STREAMING  
INTO THE REGION. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL  
TODAY AND THEN RETURN CLOSER TO NORMAL ON THURSDAY WITH SHOWER  
AND THUNDERSTORM ACTIVITY OVER THE AREA.  
 
AS FOR SEVERE WEATHER AND EXCESSIVE RAINFALL... THERE IS A  
MARGINAL SEVERE WEATHER THREAT ON THURSDAY WITH THE WARM FRONT  
AND ENERGY FROM A SHORTWAVE MOVING THROUGH THE AREA. HOWEVER,  
THE AREA WILL BE WELL WORKED OVER WITH RAIN AND CLOUD COVER ON  
THURSDAY AND UNLESS THERE IS A POCKET OF CLEARING, THERE WILL BE  
INSTABILITY ISSUES. HEAVY RAIN IS CERTAINLY POSSIBLE,  
ESPECIALLY OUT WEST, CLOSER TO THE LOW. LUCKILY, THOSE AREAS  
HAVE REMAINED FAIRLY DRY RECENTLY SO IT WILL TAKE QUITE A BIT OF  
RAIN TO RUN INTO FLOODING ISSUES.  
 

 
   
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/
 
 
LOW PRESSURE WILL BE OVER LOWER MICHIGAN ON THURSDAY EVENING,  
GRADUALLY MOVING INTO SOUTHERN ONTARIO ON FRIDAY. DEEP MOISTURE AXIS  
WILL BE OVERHEAD AT THE START OF THE PERIOD WITH GOOD COVERAGE OF  
SHOWERS FOCUSED ACROSS THE EAST HALF OF THE AREA AHEAD OF SHORTWAVE  
ENERGY LIFTING NORTHEAST ACROSS LAKE ERIE INTO CANADA. PRECIPITATION  
WILL TEND TO SHIFT EASTWARD OVERNIGHT AS DRIER MID-LEVEL AIR WRAPS  
IN FROM THE WEST. COVERAGE OF PRECIPITATION WILL BE AT A MINIMUM ON  
FRIDAY MORNING BUT WILL INCREASE AGAIN DURING THE AFTERNOON AS THE  
UPPER TROUGH PASSES ALOFT AND PUSHES A COLD FRONT SOUTH ACROSS THE  
AREA. MODERATE INSTABILITY IS EXPECTED TO DEVELOP SOUTH OF THE  
BOUNDARY WITH SCATTERED TO NUMEROUS COVERAGE OF SHOWERS AND  
THUNDERSTORMS DURING THIS AFTERNOON, SHIFTING TOWARDS CENTRAL OHIO  
BY EVENING. HIGHS ON FRIDAY WILL BE IN THE LOWER 80S WITH DEWPOINTS  
STILL NEAR THE 70S DEGREE MARK.  
 
A DRIER AIRMASS WILL ARRIVE BEHIND THE COLD FRONT FOR THE WEEKEND.  
WILL HOLD ONTO A LOW 20 POP INTO SATURDAY AS A SECONDARY TROUGH  
APPEARS TO SLIDE SOUTH ACROSS THE AREA BUT ANY SHOWERS WILL BE  
ISOLATED WITH BEST CHANCES FOCUSED IN OUR FAR SOUTHERN COUNTIES.  
ALTHOUGH TEMPERATURES WILL STILL BE NEAR THE 80 DEGREE MARK,  
CONDITIONS WILL FEEL MORE COMFORTABLE WITH LOWER HUMIDITY.  
 

 
   
LONG TERM /SUNDAY THROUGH TUESDAY/
 
 
SURFACE HIGH PRESSURE BUILDS SOUTH OUT OF CANADA ACROSS THE EASTERN  
GREAT LAKES BY SUNDAY THEN MOVES TO NEW ENGLAND ON MONDAY. WILL  
START TO SEE SOME RETURN MOISTURE MOVING BACK INTO THE AREA BY  
MONDAY NIGHT WITH SCATTERED SHOWERS AND THUNDERSTORMS ON TARGET FOR  
TUESDAY AS ANOTHER UPPER TROUGH MOVES OUT OF THE PLAINS ACROSS THE  
GREAT LAKES REGION. TEMPERATURES WILL TREND A FEW DEGREES WARMER  
SUNDAY INTO MONDAY, THEN DROP BACK TUESDAY WITH GREATER COVERAGE OF  
CLOUDS/PRECIPITATION AND THE PASSAGE OF A COLD FRONT LATER IN THE  
DAY.  
 

 
   
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
 
 
HIGH PRESSURE JUST SOUTHEAST OF THE AREA WILL CONTINUE TO KEEP  
THE AREA MOSTLY DRY FOR THE FIRST HALF OF TODAY AS LOW PRESSURE  
MOVES IN FROM THE WEST. AHEAD OF THE LOW, WIDESPREAD CIRRUS IS  
STREAMING IN AND WILL CONTINUE IMPACT ALL OF THE TERMINALS  
TODAY. OTHER THAN THAT, STILL AWAITING THE LOW PRESSURE SYSTEM  
TO REACH THE AREA TONIGHT INTO THURSDAY. A MID-LEVEL DECK OF  
CLOUDS WILL MOVE IN FOLLOWED BY WIDESPREAD SHOWERS AND  
THUNDERSTORMS. HAVE BEGUN A VCSH AND VCTS MENTIONS AT ALL  
TERMINALS FOR TONIGHT INTO THURSDAY MORNING. THE TIMING IS  
MOSTLY WITH THE WARM FRONT MOVING OVER THE FORECAST AREA. WINDS  
THROUGH THE PERIOD WILL GENERALLY BE LIGHT OUT OF THE SOUTH  
THROUGH THE PERIOD. COULD HAVE SOME STRONGER WINDS AT KERI WITH  
THE DOWNSLOPE SOUTHERLY WIND DIRECTION.  
 
OUTLOOK...NON-VFR POSSIBLE SHOWERS AND THUNDERSTORMS ON  
THURSDAY NIGHT, LINGERING INTO FRIDAY.  
 

 
   
MARINE
 
 
SOUTHWESTERLY WINDS OF 5 TO 15 KNOTS CAN BE EXPECTED TODAY.  
SOUTHERLY WINDS WILL INCREASE TO 10-15 KNOTS THURSDAY INTO FRIDAY  
AHEAD OF LOW PRESSURE TRACKING OUT OF THE PLAINS ACROSS THE CENTRAL  
GREAT LAKES. A COLD FRONT WILL PUSH SOUTH ACROSS THE LAKE FRIDAY  
AFTERNOON WITH WAVES BUILDING TO 2 TO 4 FEET BY FRIDAY EVENING  
BEHIND THE FRONT. IT CONTINUES TO LOOK LIKE WE WILL BE BELOW SMALL  
CRAFT CRITERIA BUT WILL NEED TO BE WATCHED.  
 
THE FLOW SHIFTS TO NORTHEASTERLY ON SATURDAY AND MAY KEEP CONDITIONS  
A LITTLE CHOPPY ALONG THE SOUTH SHORE OF THE LAKE. IMPROVING MARINE  
CONDITIONS CAN BE EXPECTED BY SUNDAY AS HIGH PRESSURE BUILDS  
OVERHEAD.  
 

 
   
CLE WATCHES/WARNINGS/ADVISORIES
 
 
OH...NONE.  
PA...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...SEFCOVIC  
NEAR TERM...GRIFFIN  
SHORT TERM...KEC  
LONG TERM...KEC  
AVIATION...SEFCOVIC  
MARINE...KEC  
 
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