669  
FXUS61 KCLE 200001  
AFDCLE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CLEVELAND OH  
801 PM EDT MON APR 19 2021  
   
SYNOPSIS
 
 
A COLD FRONT STRETCHING ACROSS LOWER MICHIGAN TO NORTHERN  
ILLINOIS WILL CONTINUE EAST TONIGHT AND SLOWLY CROSS THE AREA ON  
TUESDAY. LOW PRESSURE WILL MOVE NORTHEAST ALONG THIS SLOWING  
FRONT ON TUESDAY NIGHT AND QUICKLY EXIT THE REGION ON WEDNESDAY.  
A RESIDUAL TROUGH WILL REMAIN ACROSS THE REGION INTO THURSDAY  
MORNING. HIGH PRESSURE WILL BUILD FROM THE SOUTHWEST LATER ON  
THURSDAY INTO FRIDAY.  
 

 
   
NEAR TERM /THROUGH TUESDAY NIGHT/
 
 
CLOUDS CONTINUE TO MOVE EAST ACROSS THE AREA AT THIS TIME IN  
ADVANCE OF THE COLD FRONT THAT WILL USHER IN MUCH COLDER AIR TO  
THE LOCAL AREA. VIRGA CONTINUES TO PUSH INTO THE WESTERN  
PORTIONS OF THE AREA WHILE THE REST OF THE AREA IS MAINLY SEEING  
THE CLOUD COVER. TEMPERATURES REMAIN THE LOWER 60S IN THE  
EASTERN HALF OF THE AREA WHILE THE COLD FRONT MOVED INTO THE  
NORTHWEST PART OF THE AREA DROPPING TEMPERATURES INTO THE 40S AT  
THIS TIME. NO MAJOR CHANGES WITH THIS UPDATE.  
 
PREVIOUS DISCUSSION...  
 
A COLD FRONT STRETCHING FROM THE THUMB REGION OF MICHIGAN TO  
NORTHERN INDIANA WILL CONTINUE EAST TOWARDS THE FORECAST AREA  
THIS EVENING. RAIN CONTINUES AHEAD OF THIS FRONT BUT IS BATTLING  
A VERY DRY LOW LEVEL AIR MASS ACROSS THE REGION AND MANY OF THE  
RETURNS ON RADAR THIS AFTERNOON ARE NOT REACHING THE GROUND.  
THE RAIN THAT IS ACTUALLY MEASURING IS IMMEDIATELY WITH THE  
FRONT, WHERE TEMPERATURES ARE DROPPING 20 DEGREES AND RAIN ISN'T  
ABLE TO EVAPORATE AS QUICKLY. TIMING THIS FEATURE EAST ACROSS  
THE AREA, WHILE ACCOUNTING FOR LOW LEVEL DRYING, HAVE LOW POPS  
FOR TONIGHT WITH THE HIGHEST OVER NE OH/NW PA WHERE SOME ADDED  
MOISTURE OFF LAKE ERIE GIVES THE HIGHEST CONFIDENCE IN RAIN  
CHANCES WITH THE FRONT. THE FRONT WILL SLOWLY MOVE THROUGH THE  
AREA ON TUESDAY, BUT AFTER BEING REMOVED FROM THE BETTER UPPER  
LEVEL FORCING, ANY RAIN SHOWERS SHOULD FIZZLE OUT BY LATE  
MORNING. TEMPERATURES TONIGHT WILL BE FALLING INTO THE UPPER 30S  
TO LOWER 40S AND THEN ANY RECOVERY ON TUESDAY WILL BE HIGHLY  
DEPENDENT UPON THE FRONTAL LOCATION, BUT A GOOD GRADIENT FROM  
NORTH TO SOUTH WILL BE PRESENT ACROSS THE FORECAST AREA WITH 40S  
TO THE NORTH AND 50S TO THE SOUTH AHEAD OF THE FRONT.  
 
THE BIGGEST STORY FOR THE NEAR TERM PERIOD WILL BE THE SECOND  
HALF OF TUESDAY, AS SNOW MAKES A TRIUMPHANT RETURN TO THE  
REGION. (SORRY, FOLKS!) LOW PRESSURE WILL DEVELOP OVER THE SOUTH  
CENTRAL UNITED STATES AND FOLLOW THE FRONT NORTHEAST INTO THE  
FORECAST AREA. WITH THE LOW, A POTENT SHORTWAVE TROUGH WILL  
ENTER THE GREAT LAKES REGION GIVING GOOD SUPPORT FOR  
PRECIPITATION ACROSS THE REGION. STRONG LOW-LEVEL FRONTOGENETIC  
FORCING WILL ALSO BE ON THE NORTHWEST SIDE OF THIS SYSTEM  
ALLOWING FOR ADDITIONAL LIFT FOR PRECIPITATION. AIR SHOULD BE  
SUFFICIENTLY COLD ENOUGH FOR RAIN TO CHANGEOVER TO SNOW ON  
TUESDAY EVENING. A TROWAL PIVOTING THROUGH THE REGION LATE  
TUESDAY NIGHT COULD BRIEFLY ENHANCE SNOWFALL RATES ACROSS THE  
REGION AND ALLOW FOR ACCUMULATIONS, ESPECIALLY IN NW OH.  
HOWEVER, SURFACE TEMPERATURES REMAIN WARM AND A SIGNIFICANT  
DIFFERENCE IN ACCUMULATIONS ON GRASSY SURFACES VS. ROADWAYS WILL  
BE NOTED. WITH ALL THAT SAID, WILL MAINTAIN A BROAD AREA OF 1 TO  
3 INCHES OF SNOW ON TUESDAY NIGHT, ALTHOUGH WHERE HEAVIER  
SNOWFALL RATES, AND PERHAPS BANDING, EXISTS IN NW OH, 4 INCHES  
COULD BE POSSIBLE. OUTSIDE OF THAT, COLD TEMPERATURES ARE  
EXPECTED ON TUESDAY NIGHT AND HAVE ISSUED A FREEZE WATCH FOR  
COUNTIES WHERE THE GROWING SEASON HAS STARTED AND TEMPERATURES  
32 OR LOWER ARE EXPECTED.  
 

 
   
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
 
 
THE UPPER-LEVEL TROUGH AND ASSOCIATED LOW PRESSURE SYSTEM SYSTEM  
WILL BE MOVING OFF TO THE EAST DURING THE DAYTIME HOURS ON  
WEDNESDAY. IT SEEMS LIKELY THAT THERE WILL STILL BE ONGOING SNOW  
WITH SMALL AREAS OF HEAVY SNOW EARLY WEDNESDAY MORNING.  
PRECIPITATION RATES WILL BE DIMINISHING THROUGH THE LATE MORNING AND  
EARLY AFTERNOON HOURS AS THE BEST SYNOPTIC-SCALE LIFT MOVES OFF TO  
THE EAST, WHICH COMBINED WITH THE APRIL SUN ANGLE, AND SLIGHTLY  
INCREASING DAYTIME TEMPERATURES SHOULD LIMIT ANY ADDITIONAL SNOW  
ACCUMULATION THROUGH THE DAYTIME HOURS. ADDITIONAL SNOW  
ACCUMULATIONS OF LESS THAN AN INCH ARE EXPECTED ACROSS NORTHERN AND  
NORTHEAST OHIO, WHILE UP TO ONE TO TWO INCHES IS POSSIBLE IN  
NORTHWEST PENNSYLVANIA (ESPECIALLY INLAND). ACCUMULATIONS SHOULD  
MAINLY BE RESERVED FOR GRASSY AND ELEVATED SURFACES. HIGH SNOW RATES  
COULD RESULT IN SNOW ACCUMULATING ON ROADWAYS, ESPECIALLY BEFORE  
SUNRISE, BUT WILL LIKELY BE SHORTLIVED AS INCREASING TEMPERATURES  
AND HIGH APRIL SUN ANGLE SHOULD MELT THIS VERY QUICKLY DURING THE  
DAYTIME HOURS.  
 
NORTHWEST FLOW WILL ENSUE WITH COLD TEMPERATURES ALOFT IMMEDIATELY  
UPSTREAM THE DEPARTING LOW. THIS WILL RESULT IN SIGNIFICANT LAKE-  
INDUCED CLOUD COVER AND A TRANSITION FROM SYSTEM-PRECIPITATION TO  
LAKE EFFECT PRECIPITATION BY WEDNESDAY AFTERNOON/EVENING. ADVECTION  
OF COLD AIR ALOFT OVER WARM LAKE ERIE WATER TEMPERATURES OF MID TO  
UPPER 40S WILL RESULT IN DEEPENING EQUILIBRIUM LEVELS AND PEAK LAKE-  
INDUCED SBCAPE OF UP TO 500 J/KG BY WEDNESDAY NIGHT. ADDITIONAL SNOW  
ACCUMULATIONS ARE LIKELY WEDNESDAY NIGHT, THOUGH THERE IS STILL A  
GREAT DEAL OF UNCERTAINTY REGARDING THE MOISTURE PROFILE (MODELS ARE  
PROJECTING LOW MOISTURE CONTENT), ALONG WITH EVOLUTION OF LAKE  
EFFECT BANDS/CELLS. ADDITIONALLY, SURFACE TEMPERATURES ARE EXPECTED  
TO DROP SIGNIFICANTLY WEDNESDAY NIGHT INTO THURSDAY MORNING, WITH  
LOWS IN THE MID TO UPPER 20S AWAY FROM THE LAKE AND LOW 30S NEAR THE  
LAKESHORE. RECORD LOWS AT AREA CLIMATE SITES ARE IN THE LOW 20S FOR  
APRIL 21, SO CURRENT FORECAST IS ONLY A FEW DEGREES AWAY FROM RECORD  
LOWS AT MANY SPOTS. LAKE EFFECT PRECIPITATION AND CLOUD COVER WILL  
SLOWLY DIMINISH FROM WEST TO EAST THURSDAY. HIGH PRESSURE BUILDING  
INTO THE REGION WILL BE CENTERED OVER THE TENNESSEE VALLEY THURSDAY  
WITH ANOTHER ROUND OF COLD TEMPERATURES WITH MINIMUM TEMPERATURES IN  
THE LOW TO MID 30S.  
 

 
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
 
THERE WILL BE A SLOW TREND BACK TO NEAR NORMAL TEMPERATURES THROUGH  
THE WEEKEND, THOUGH THERE IS STILL A FAIR AMOUNT OF SPREAD IN MODEL  
GUIDANCE. BEST PRECIPITATION CHANCES ARE EXPECTED SATURDAY AND  
SATURDAY NIGHT AND AN UPPER-LEVEL TROUGH MOVES ACROSS THE REGION.  
MOST MODEL GUIDANCE HAS A PRECIPITATION-FREE MONDAY WITH NEAR-NORMAL  
TEMPERATURES.  
 

 
   
AVIATION /00Z TUESDAY THROUGH SATURDAY/
 
 
THE COLD FRONT BISECTS THE AREA AT THIS TIME AND A LINE OF  
SHOWERS DEVELOPED WITH THE FRONT. OTHERWISE, EXPECTING CEILINGS  
TO LOWER THROUGH THE NIGHT AND IMPROVE DURING THE MORNING HOURS  
TOMORROW. THE NEXT ROUND OF MOISTURE WILL START TO MOVE INTO  
THE AREA AFTER 00Z TOMORROW EVENING WITH THE SURFACE LOW  
PRESSURE SYSTEM. EXPECT CEILINGS TO LOWER ONCE AGAIN AND A  
BETTER CHANCE FOR SHOWERS AT THAT TIME. WINDS WILL GRADUALLY  
DIMINISH OVERNIGHT TONIGHT BEHIND THE COLD FRONT AND WIND  
DIRECTION IS SHIFTING TO A NORTHWEST DIRECTION.  
 
OUTLOOK...NON-VFR LIKELY IN SNOW INTO WEDNESDAY MORNING.  
LINGERING NON-VFR POSSIBLE IN SCATTERED LAKE EFFECT RAIN AND/OR  
SNOW SHOWERS WEDNESDAY INTO THURSDAY. NON-VFR POSSIBLE SATURDAY.  
 

 
   
MARINE
 
 
WESTERLY WINDS NEAR 15 KNOTS WILL CONTINUE THROUGH TONIGHT ACROSS  
LAKE ERIE. LOW PRESSURE DEVELOPS OVER THE OHIO VALLEY TOMORROW,  
MOVING TOWARDS THE NEW ENGLAND COAST BY WEDNESDAY NIGHT. THIS RESULT  
IN THE DEVELOPMENT OF NORTHEAST TO NORTH WINDS OF AROUND 15 TO 20  
KNOTS TUESDAY NIGHT INTO WEDNESDAY MORNING BEFORE WEAKENING AND  
SHIFTING TO OUT OF THE NORTHWEST WEDNESDAY THROUGH THURSDAY MORNING.  
ON THURSDAY WINDS BECOME MORE WESTERLY AS HIGH PRESSURE BUILDS  
EASTWARD ACROSS THE TENNESSEE VALLEY, WITH WESTERLY WINDS OF 15 TO  
20 KNOTS EXPECTED THURSDAY THROUGH AT LEAST FRIDAY MORNING.  
 

 
   
CLE WATCHES/WARNINGS/ADVISORIES
 
 
OH...FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING  
FOR OHZ003-006-017-027-036.  
PA...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...SEFCOVIC  
NEAR TERM...LOMBARDY/SEFCOVIC  
SHORT TERM...SAUNDERS  
LONG TERM...SAUNDERS  
AVIATION...LOMBARDY  
MARINE...SAUNDERS  
 
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