620  
FXUS61 KBUF 180243  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1043 PM EDT SAT APR 17 2021  
   
SYNOPSIS
 
 
WEAK HIGH PRESSURE WILL BRING MAINLY DRY WEATHER THROUGH MONDAY,  
ALTHOUGH A FEW PASSING WEAK DISTURBANCES ALOFT MAY PRODUCE A FEW  
LIGHT, ISOLATED SHOWERS AT TIMES. TEMPERATURES WILL CONTINUE TO  
SLOWLY WARM EACH DAY THROUGH MONDAY. UNSETTLED WEATHER WILL THEN  
RETURN BY MIDWEEK AS A COLD FRONT AND LOW PRESSURE CROSS THE REGION.  
UNSEASONABLY COLD AIR WILL MOVE BACK INTO OUR AREA BY LATE NEXT  
WEEK BEHIND THIS SYSTEM.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
RADAR SHOWS TWO SMALL AREAS OF ISOLATED SHOWERS, ONE DROPPING ACROSS  
LAKE ERIE TOWARD STURGEON POINT AND LAKE ERIE BEACH AND THE  
OTHER SLIDING SSE ACROSS EASTERN LAKE ONTARIO. WEAK SHORTWAVE  
OVER THE AREA WILL CONTINUE TO RESULT IN THESE SPARSE COVERAGE  
ISOLATED SHOWERS REST OF TONIGHT, WITH BEST CHANCE CLOSER TO A  
SLIGHTLY BETTER POCKET OF DEEPER MOISTURE ACROSS EASTERN LAKE  
ONTARIO REGION. MOST AREAS WILL STAY DRY. TEMPS DROPPED QUICKLY  
EAST OF LAKE ONTARIO WITH SOME PARTIAL CLEARING THERE THIS  
EVENING. CLOUDS ARE BACK ON THE INCREASE THOUGH SO TEMPS WILL  
LIKELY RISE BACK UP A FEW DEGREES REST OF TONIGHT. OVERALL  
THOUGH SKIES MORE CLOUDY THAN NOT WILL WITH THE SHORTWAVE OVER  
THE AREA WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH, WITH  
LOWS IN THE MID TO UPPER 30S IN MOST LOCATIONS.  
 
SUNDAY THE SLOW MOVING SHORTWAVE WILL EXIT THE EASTERN LAKE ONTARIO  
REGION BY MIDDAY, WITH ANY SCATTERED SHOWERS TAPERING OFF. A MID  
LEVEL RIDGE AND WEAK SURFACE HIGH WILL THEN BUILD INTO THE EASTERN  
LAKE ONTARIO REGION. THIS WILL BRING DRY WEATHER IN MOST LOCATIONS.  
DIURNAL HEATING AND RELATIVELY COOL TEMPERATURES ALOFT WILL STEEPEN  
LAPSE RATES IN THE AFTERNOON, AND MAY PRODUCE A FEW SCATTERED  
SHOWERS FORMING PREFERENTIALLY NEAR TERRAIN AND LAKE BREEZE  
BOUNDARIES ACROSS NEARBY SOUTHERN ONTARIO, PENNSYLVANIA, THE SAINT  
LAWRENCE VALLEY, AND EASTERN NY. SUBSIDENCE BENEATH THE MID LEVEL  
RIDGE AND EXPANDING STABLE LAKE SHADOWS SHOULD GENERALLY KEEP THESE  
SHOWERS AWAY FROM OUR AREA. TEMPERATURES WILL CONTINUE THEIR SLOW  
RECOVERY, WITH HIGHS IN THE MID TO UPPER 50S IN MOST AREAS, COOLER  
ALONG THE LAKE ERIE AND LAKE ONTARIO SHORE.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
 
 
ANY DIURNALLY DRIVEN SHOWERS ON SUNDAY WILL FIZZLE OUT AFTER SUNSET  
MOVING INTO SUNDAY NIGHT. ANOTHER WEAK SHORTWAVE WILL APPROACH FROM  
THE WEST AND CROSS SOUTH OF THE AREA MONDAY NIGHT. THIS WAVE SHOULD  
REMAIN FAR ENOUGH SOUTH THAT ANY DEVELOPING OVERNIGHT SHOWERS  
ASSOCIATED WITH THIS FEATURE SHOULD REMAIN SOUTH OF THE NY/PA  
BORDER, BUT A QUICK CLIPPING INTO SOUTHERN CATTARAUGUS AND ALLEGANY  
COUNTIES CAN'T BE ENTIRELY RULED OUT. LOWS SUNDAY NIGHT WILL BE IN  
THE MID 30S TO LOW 40S.  
 
THE SHORTWAVE LIFTS TO THE NORTHEAST MONDAY WITH ANY SPOTTY  
DIURNALLY DRIVEN SHOWERS TIED TO THIS FEATURE. A MOSTLY DRY DAY IS  
EXPECTED AS SHOWER ACTIVITY SHOULD REMAIN MAINLY TO THE EAST OF THE  
AREA. MONDAY LIKELY TO BE THE WARMEST DAY OF THE WEEK WITH THE  
MAJORITY OF THE AREA SEEING HIGHS IN THE UPPER 50S TO MID 60S. WARM  
AIR ADVECTION AHEAD OF THE NEXT SYSTEM WILL HELP MODERATE OVERNIGHT  
TEMPERATURES AS WELL, ESPECIALLY FOR THE HIGHER TERRAIN LOCATIONS.  
LOWS WILL BE IN THE LOW 40S, WITH UPPER 30S ALONG THE NIAGARA  
FRONTIER AND ON THE TUG HILL.  
 
ATTENTION THEN TURNS TO AN UPPER LEVEL CLOSED LOW OVER SOUTHERN  
ONTARIO PROVINCE. A MORE POTENT SHORTWAVE WILL ROUND THE BASE OF THE  
ASSOCIATED TROUGH, BRINGING A COLD FRONT TO THE AREA LATE MONDAY  
NIGHT, SLOWLY INCREASING RAIN CHANCES FOR WESTERN NY MOVING INTO  
TUESDAY MORNING. HOWEVER, THE FRONT WILL STALL OUT AS IT RUNS UP  
AGAINST A WEAKLY AMPLIFYING OFFSHORE RIDGE, SERVING TO BREAK UP THE  
LINE OF SHOWERS ASSOCIATED WITH THE FRONT AND SETTING UP A  
SOUTHWEST/NORTHEAST ORIENTED BAROCLINIC ZONE OVER THE REGION  
TUESDAY. THIS WILL COMPLICATE TUESDAY'S TEMPERATURE FORECAST SOME,  
AS THE POSITION OF THIS BOUNDARY WILL INFLUENCE HOW MUCH DIURNAL  
HEATING IS OFFSET BY INCREASED CLOUD COVER AND THE COOLER AIR  
FILTERING IN BEHIND THE BOUNDARY ON A MORE NORTHWESTERLY FLOW. AS OF  
NOW, CURRENTLY EXPECTING HIGH TEMPERATURES RANGING FROM THE LOW 50S  
NEAR THE LAKES TO THE LOW 60S FURTHER INLAND CLOSER TO THE FINGER  
LAKES REGION.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
 
 
THE CLOSED LOW OVER THE HUDSON BAY, SPANNING ITS ASSOCIATED TROUGH  
SOUTH ACROSS THE MID-WESTERN STATES, WILL ALLOW AN ADDITIONAL POTENT  
SHORTWAVE TO PASS THROUGH ITS BASE TUESDAY NIGHT, WHICH WILL HELP  
ADVANCE THE TROUGH EAST AND PULL THE CLOSED LOW SOUTH OUT OF THE  
HUDSON BAY AND INTO THE NORTHERN GREAT LAKES BY WEDNESDAY NIGHT. THE  
CLOSED LOW WILL CONTINUE TO ALLOW A FEW SHORTWAVES TO ROTATE THROUGH  
WHILE IT CROSSES OVERHEAD OF NORTHEASTERN NEW YORK THURSDAY BEFORE  
HEADING NORTHEAST INTO THE CANADIAN MARITIMES. UPPER LEVEL RIDGING  
WILL THEN ENSUE FOR THE END OF THE WEEK.  
 
WHILE THE SHORTWAVE ROUNDS THE BASE OF THE UPPER LEVEL TROUGH ON  
TUESDAY, THIS WILL NOT ONLY SLOWLY ADVANCE THE COLD FRONT EASTWARD,  
BUT ALSO INDUCE A SURFACE LOW TO FORM OVER MISSOURI/ILLINOIS. THIS  
LOW WILL THEN PROGRESS NORTHEAST OVERHEAD OF NY STATE, PUSHING THE  
COLD FRONT THROUGH FIRST LATE TUESDAY NIGHT AND WEDNESDAY.  
THEREFORE, EXPECT A DRY START TO THE DAY ON TUESDAY WITH CHANCES FOR  
SOME RAIN SHOWERS TO INCREASE LATE TUESDAY AFTERNOON THROUGH  
WEDNESDAY. A MUCH COLDER AIR MASS WILL WORK ITS WAY ACROSS THE  
REGION WEDNESDAY, WITH NEARLY A 15 DEGREE DROP IN TEMPERATURE AT  
850MB. HIGH TEMPERATURES WEDNESDAY WILL LIKELY OCCUR EARLY IN THE  
DAY BEFORE THE FRONTAL PASSAGE, WITH HIGHS IN THE UPPER 40S AND LOW  
50S.  
 
AS THE SURFACE LOW DEPARTS NORTHEAST OUT OF THE AREA, ONLY CHANCES  
FOR A FEW LAKE ENHANCED SNOW SHOWERS WILL LIE ACROSS THE FAR EASTERN  
PORTIONS OF THE AREA WEDNESDAY NIGHT. YET ANOTHER SHORTWAVE WILL  
PASS THROUGH THE NOW UPPER LEVEL CLOSED LOW, WHICH WILL INTERACT  
WITH THE LEFTOVER WRAP AROUND MOISTURE THURSDAY TO CONTINUE TO  
SUPPORT THE LAKE ENHANCED SHOWERS SNOW SHOWERS IN THE EARLY MORNING  
BEFORE SWITCHING TO ALL RAIN DUE TO THE ADDITION OF THE SUN FOR  
PLACES ACROSS THE FINGER LAKES REGION AND TO ITS EAST. WHILE A MUCH  
COLDER AIR MASS OVERHEAD WOULD TYPICALLY SUPPORT COLDER TEMPERATURES  
(TO THE TUNE OF NEAR FREEZING), THANKS TO THE HIGHER SUN ANGLE THIS  
TIME OF YEAR HIGH TEMPERATURES WILL WARM UP INTO THE 40S.  
 
UPPER LEVEL RIDGING LATE THURSDAY NIGHT THROUGH FRIDAY WILL PROMOTE  
MAINLY DRY CONDITIONS. LOOKING INTO THE WEEKEND, A SHORTWAVE  
ATTACHED TO THE NEXT INCOMING UPPER LEVEL TROUGH MAY ROLL THROUGH  
WHICH WILL SUPPORT A FRONTAL BOUNDARY TO APPROACH THE AREA SATURDAY.  
HOWEVER, THIS FAR OUT THE MODEL GUIDANCE IS IN DISAGREEMENT WITH  
TIMING OF THE FEATURE AND THEREFORE HAVE LOW CHANCES FOR SHOWERS  
SATURDAY. OTHERWISE, UPPER LEVEL RIDGING WILL HELP ADVECT WARM AIR  
BACK INTO THE REGION, REBOUNDING TEMPERATURES INTO THE 50S FRIDAY  
AND EVEN A FEW LOW 60S SATURDAY.  
 

 
   
AVIATION /03Z SUNDAY THROUGH THURSDAY/
 
 
WEAK SHORTWAVE WILL CONTINUE TO DRIFT EAST ACROSS THE AREA TONIGHT,  
WITH A FEW SHOWERS POSSIBLE THROUGH SUNDAY MORNING, MAINLY EAST OF  
LAKE ONTARIO. EVEN SO, MOST AREAS WILL SEE NO RAIN.  
 
AFTER MAINLY VFR CIGS THIS EVENING, MVFR CIGS WILL BECOME MORE  
WIDESPREAD AGAIN LATE TONIGHT AND SUNDAY MORNING EAST OF LAKE  
ONTARIO, WITH SOME IFR POSSIBLE ACROSS HIGHER TERRAIN. A FEW PATCHES  
OF MVFR CIGS AREA ALSO POSSIBLE EAST OF LAKE ERIE LATE TONIGHT AND  
SUNDAY MORNING.  
 
WEAK HIGH PRESSURE SURFACE AND ALOFT WILL THEN BRING A RETURN TO  
MAINLY VFR BY SUNDAY AFTERNOON WITH DIURNAL CUMULUS DEVELOPING  
INLAND FROM THE STABLE LAKE SHADOWS.  
 
OUTLOOK...  
 
MONDAY...MAINLY VFR.  
TUESDAY...MVFR TO VFR WITH A CHANCE OF SHOWERS.  
TUESDAY NIGHT AND WEDNESDAY...IFR/MVFR WITH RAIN SHOWERS BECOMING  
LIKELY.  
THURSDAY...MVFR/IFR WITH SCATTERED SNOW SHOWERS AND SOME LAKE EFFECT  
SNOW SHOWERS EAST OF THE LAKES. WINDY.  
 

 
   
MARINE
 
 
SOUTHWEST WINDS OF 10-15 KNOTS ON LAKE ERIE WILL CONTINUE TO PRODUCE  
CHOPPY CONDITIONS OVERNIGHT. WEST WINDS WILL THEN INCREASE LATE  
TONIGHT AND SUNDAY ON LAKE ONTARIO AS WELL, PRODUCING A ROUND OF  
CHOPPY CONDITIONS. IN BOTH CASES THOUGH, WINDS AND WAVES ARE  
EXPECTED TO REMAIN A LITTLE BELOW SMALL CRAFT ADVISORY CRITERIA.  
WINDS WILL THEN DIMINISH SUNDAY NIGHT, WITH GENERALLY LIGHT  
SOUTHWEST WINDS ON MONDAY.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...HITCHCOCK  
NEAR TERM...HITCHCOCK/JLA  
SHORT TERM...PP  
LONG TERM...EAJ  
AVIATION...HITCHCOCK/JLA  
MARINE...HITCHCOCK/JLA  
 
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