686  
FXUS61 KBUF 290850  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
450 AM EDT SAT APR 29 2017  
   
SYNOPSIS
 
 
A FRONT WILL STALL NEAR THE NEW YORK AND PENNSYLVANIA BORDER THROUGH  
TONIGHT AND THEN WILL GRADUALLY PUSH NORTHWARD INTO WESTERN NEW YORK  
ON SUNDAY. THIS WILL RESULT IN SCATTERED SHOWERS AND A FEW  
THUNDERSTORMS, ALTHOUGH MOST OF THE WEEKEND WILL REMAIN DRY AND  
MILD. WARMER TEMPERATURES WILL RETURN MONDAY, WITH SHOWERS AND  
THUNDERSTORMS AHEAD OF A COLD FRONT WHICH WILL CROSS THE REGION  
MONDAY EVENING.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
RADAR TRENDS SHOW THE BULK OF THE SHOWERS ALONG A STALLED FRONTAL  
BOUNDARY WELL TO OUR SOUTH, WITH SCATTERED LIGHT SHOWERS TO THE  
NORTH OF THIS. THESE WILL JUST CLIP WESTERN NEW YORK EARLY THIS  
MORNING.  
 
TODAY...MODEL CONSENSUS STALLS THE WARM FRONT JUST SOUTH OF THE  
NY/PA BORDER. THE BEST CHANCE FOR ADDITIONAL SHOWERS DURING THE  
AFTERNOON WILL BE ACROSS THE SOUTHERN TIER. MOST MESOSCALE GUIDANCE  
DEVELOPS ANOTHER CONVECTIVE WAVE THIS AFTERNOON, BUT THIS IS ALSO  
LIKELY TO TRACK ALONG THE BOUNDARY AND MAINLY PASS SOUTH OF THE  
AREA. THIS WILL RESULT IN A MAINLY DRY DAY WITH JUST A SMALL CHANCE  
OF SHOWERS ACROSS THE SOUTHERN TIER. OTHERWISE, THERE WILL BE SOME  
BREAKS OF SUNSHINE WITH HIGHS IN THE LOWER TO MID 60S IN MOST AREAS.  
THE LAKE BREEZE WILL ENHANCE THE WNW GRADIENT FLOW WITH COOLER  
TEMPERATURES NEAR THE LAKE SHORES.  
 
TONIGHT...DEVELOPING LOW PRESSURE ACROSS THE CENTRAL PLAINS WILL  
BEGIN TO INFLUENCE THE STALLED FRONTAL BOUNDARY AN PUSH IT NORTHWARD  
INTO THE REGION AS A WARM FRONT. MEANWHILE, THE MID-LEVEL THERMAL  
GRADIENT WILL SHARPEN ACROSS SOUTHERN ONTARIO, WITH AN AREA OF RAIN  
EXPECTED TO DEVELOP LATE TONIGHT. THIS MAY BRING SOME SHOWERS, AND  
POSSIBLY A THUNDERSTORM TO WESTERN NEW YORK LATE TONIGHT, WITH THE  
EVENING HOURS EXPECTED TO BE LARGELY DRY OUTSIDE OF POSSIBLY A STRAY  
SHOWER ACROSS FAR WESTERN NEW YORK. LOWS WILL BE IN THE 40S SOUTH OF  
LAKE ONTARIO WITH UPPER 30S EAST OF LAKE ONTARIO. HOWEVER,  
TEMPERATURES WILL RISE LATE IN THE NIGHT ACROSS THE WESTERN SOUTHERN  
TIER WITH THE PASSAGE OF THE WARM FRONT.  
 

 
   
SHORT TERM /SUNDAY THROUGH TUESDAY/
 
 
A CLOSED UPPER LEVEL LOW WILL MEANDER ACROSS THE SOUTHERN PLAINS  
TODAY THROUGH SUNDAY, AND THEN TOWARDS THE WESTERN CORN BELT STATES  
BY MONDAY MORNING. AHEAD OF THE UPPER LEVEL LOW DEEP SOUTHERLY FLOW  
WILL TRANSPORT MOISTURE NORTHWARD FROM THE GULF OF MEXICO.  
 
AT SURFACE AN AREA OF LOW PRESSURE FORMING NEAR SW TEXAS WILL SLOWLY  
TRACK NORTHWARD ACROSS THE PLAINS, DEEPENING SOME BY A TRAILING PV  
ANOMALY. THIS SURFACE LOW WILL NUDGE AN ELEVATED WARM FRONT  
NORTHWARD, ACROSS THE LOWER LAKES SUNDAY AND TO LAKE ONTARIO AND  
EAST OF LAKE ONTARIO SUNDAY NIGHT. INSTABILITY TRAILING THIS WARM  
FRONT WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE  
DAY SUNDAY AND INTO SUNDAY NIGHT. GREATEST CHANCES FOR STORMS WILL  
COME ALONG AND NORTH OF THE WARM FRONT. PWATS RISING TO AN INCH, AND  
TOWARDS AN INCH AND A THIRD NORTH OF THE WARM FRONT WILL FUEL THESE  
STORMS. THOUGH INSTABILITY WILL BE GREATER SOUTH OF THE WARM FRONT,  
THERE WILL STILL FEATURE A DECENT AMOUNT OF LIFT NORTH OF THE WARM  
FRONT, AND IT IS THIS LIFT THAT WILL LIKELY FORM MUCH OF THE RAIN  
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY NIGHT. GREATEST RAINFALL  
TOTALS SUNDAY AND SUNDAY NIGHT WILL LIKELY LIE ALONG LAKE ONTARIO  
AND POINTS EASTWARD. HOWEVER INSTABILITY SOUTH OF THE WARM FRONT  
WILL STILL HAVE CHANCES OF FORMING CONVECTION, AND WILL CONTINUE  
WITH CHANCES POPS, WITH ANY THUNDERTORM BRINGING LOCALLY HEAVY  
DOWNBURST OF RAIN.  
 
THERE WILL BE A GREAT DEAL OF TEMPERATURE RANGE SUNDAY, AS NORTHEAST  
AND EASTERLY FLOW ACROSS MUCH OF THE CWA MAINTAIN TEMPERATURES IN  
THE 50S AND LOWER 60S. HOWEVER A SOUTHERLY FLOW WILL EDGE NORTHWARD  
TOWARDS THE SO. TIER SUNDAY WHERE A FEW LOCATIONS WILL CLIMB INTO  
THE MID 70S.  
 
MONDAY WILL LIKELY START THE DAY DRY, WARM AND HUMID AS OUR REGION  
LIES WITHIN THE WARM SECTOR OF THIS MIDWEST STORM SYSTEM. A LINE OF  
STORMS WILL LIKELY FORM ACROSS THE WESTERN LAKE ERIE WATERS MIDDAY  
MONDAY, THEN REACHING WNY LATER IN THE AFTERNOON. THESE STORMS WILL  
HAVE THE POTENTIAL TO BECOME STRONG TO SEVERE AS A LLJ INCREASES  
AHEAD OF THE UPPER LEVEL LOW. 0-6 KM BULK SHEAR WIND VALUES RISE TO  
65 TO 75 KNOTS, AND DEWPOINTS RISING INTO THE LOWER 60S SUPPORTING  
SBCAPE VALUES OF A 1000 J/KG OR MORE ALONG WITH LIFT AHEAD OF AN  
APPROACHING COLD FRONT SHOULD BE MORE THAN ENOUGH TO FORM STRONG  
THUNDERSTORMS. THERE WILL BE A LITTLE CONCERN THAT CLOUD COVER,  
ESPECIALLY OVER THE NIAGARA FRONTIER MAY LIMIT SOME OF THE  
INSTABILITY AND STRENGTH OF THE STORMS, WHILE FARTHER TO THE EAST,  
ACROSS THE GENESEE VALLEY AND FINGER LAKES REGION MORE AMPLE  
SUNSHINE WILL BE POSSIBLE. THESE STORMS WILL CONTINUE THROUGH THE  
EVENING HOURS, TRACKING ACROSS THE CWA. AS THEY REACH THE EASTERN  
LAKE ONTARIO REGION, LIKELY DURING THE EVENING OR LATE EVENING  
HOURS, THE DAYTIME INSTABILITY WILL BE WANING, AND REDUCING THE  
STRENGTH OF THE CONVECTION.  
 
TEMPERATURES MONDAY WILL RISE INTO THE UPPER 70S AND LOWER 80S, WITH  
MID 80S POSSIBLE WITHIN THE SOUTHERN GENESEE VALLEY. HIGHS MONDAY  
WILL LIKELY NOT BE AS HIGH AS THIS PAST THURSDAY, AS 850 HPA  
TEMPERATURES WILL BE A FEW DEGREES COOLER, AND THERE WILL LIKELY BE  
A BIT MORE CLOUD POTENTIAL.  
 
TUESDAY MOIST CYCLONIC FLOW WILL CONTINUE ACROSS OUR REGION AS THE  
UPPER LEVEL LOW, AND SURFACE LOW PASS BY TO OUR NORTHWEST. GUSTY  
WINDS WILL BE LIKELY TUESDAY, ESPECIALLY NORTHEAST OF THE LAKES, AND  
ACROSS THE LAKE PLAINS WHERE GUSTS COULD REACH 40 MPH. A LOW LEVEL  
JET OF 45 TO 50 KNOTS WILL RESIDE JUST ABOVE THE SURFACE, NEAR 2-3K  
FEET. HOWEVER THE CLOUDS THROUGH THE DAY WILL LIMIT THE DAYTIME  
MIXING HEIGHT, WITH UNCERTAINTY STILL EXISTING AS TO HOW STRONG  
THESE GUSTS WILL BECOME. WILL CONTINUE TO MENTION THE STRONG WIND  
POTENTIAL, AS WELL AS THE STRONG TO SEVERE THUNDERSTORMS IN THE HWO  
FOR NOW. TEMPERATURES TUESDAY WILL BE MUCH COOLER, WITH HIGHS RANGING  
THROUGH THE 50S ACROSS THE REGION.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
 
 
COOL AND UNSETTLED WEATHER LOOK TO BE THE NORM FOR MOST DAYS OVER  
THE NEXT FEW WEEKS AS A MEAN LONGWAVE TROUGH REMAINS IN PLACE OVER  
THE GREAT LAKES AND NORTHEAST, WITH FREQUENT SHORTWAVES AND  
ASSOCIATED SURFACE LOWS BRINGING PERIODS OF SHOWERS AND FRESH  
DELIVERIES OF COOL AIR.  
 
TUESDAY NIGHT AND WEDNESDAY THE DEEP UPPER LEVEL TROUGH OVER THE  
GREAT LAKES WILL MOVE EAST ACROSS QUEBEC AND WEAKEN, BUT WILL STILL  
MAINTAIN ENOUGH INFLUENCE ACROSS OUR REGION TO KEEP BELOW NORMAL  
TEMPERATURES IN PLACE RIGHT THROUGH THE END OF NEXT WEEK. 850MB  
TEMPS RUN FROM -2C TO -4C WEDNESDAY DEPENDING ON MODEL OF CHOICE,  
AND ONLY IMPROVE TO AROUND +1C BY FRIDAY.  
 
THE WEATHER WILL REMAIN UNSETTLED AS WELL. TUESDAY NIGHT AND  
WEDNESDAY THE EASTWARD MOVING TROUGH WILL COMBINE WITH COOL AIR  
ALOFT AND REMAINING WRAP AROUND MOISTURE TO SUPPORT SCATTERED  
SHOWERS, ESPECIALLY ACROSS THE HIGHER TERRAIN WITH AN ADDED BOOST  
FROM UPSLOPE FLOW. IT SHOULD BRIEFLY DRY OUT WEDNESDAY NIGHT AS A  
BUBBLE OF HIGH PRESSURE BUILDS OVER THE EASTERN GREAT LAKES AND NEW  
ENGLAND.  
 
BY THURSDAY AND FRIDAY OF NEXT WEEK ANOTHER TROUGH IS FORECAST TO  
DIG INTO THE EASTERN US, AND POTENTIALLY PHASE AND CLOSE OFF INTO A  
MID LEVEL CLOSED LOW. AN ASSOCIATED LOW WILL FORM ALONG OR INLAND OF  
THE EAST COAST AND MOVE SLOWLY NORTHWARD. IF THIS MATERIALIZES, IT  
WILL SPREAD CLOUDS AND MORE SHOWERS INTO THE REGION FOR THE END OF  
THE WEEK.  
 

 
   
AVIATION /09Z SATURDAY THROUGH WEDNESDAY/
 
 
FOR THE 09Z TAF CYCLE THERE IS WIDESPREAD MID AND HIGH LEVEL CLOUDS  
ACROSS THE REGION WHICH ARE WELL IN THE VFR CATEGORY.  
RADAR SHOWS SCATTERED LIGHT SHOWERS ACROSS WESTERN NEW YORK, BUT THE  
APPEAR SO LIGHT THEY MAY NOT EVEN SATURATE THE BOUNDARY LAYER. AS A  
RESULT, SUSPECT MOS AVIATION GUIDANCE IS TOO PESSIMISTIC WITH VFR  
CONDITIONS LASTING THROUGH THIS MORNING WITH THE POSSIBLE EXCEPTION  
OF JHW WHERE LOWER CIGS ARE POSSIBLE.  
 
DURING THE DAY, EXPECT MAINLY VFR CONDITIONS WITH MVFR CIGS A  
POSSIBILITY AT JHW WITH ANOTHER ROUND OF SHOWERS POSSIBLE. THESE  
TRENDS SHOULD CONTINUE THROUGH THIS EVENING, WITH ONLY VERY  
SMALL CHANCES FOR SHOWERS ACROSS WESTERN NEW YORK. THESE CHANCES  
WILL INCREASE LATE IN THE NIGHT, WITH INCREASING CHANCES FOR MVFR  
CONDITIONS AFTER MIDNIGHT.  
 
OUTLOOK...  
SUNDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.  
MONDAY...MVFR TO LOCALLY IFR WITH SHOWERS AND THUNDERSTORMS  
LIKELY.  
TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.  
 

 
   
MARINE
 
 
A FRONTAL BOUNDARY WILL BECOME DRAPED ACROSS THE LOWER GREAT LAKES  
TO START THIS WEEKEND, THOUGH WINDS AND WAVES WILL REMAIN MINIMAL  
THROUGH THIS EVENING.  
 
STRENGTHENING EAST TO NORTHEASTERLY WINDS WILL LIKELY BRING  
SMALL CRAFT ADVISORY CONDITIONS TO THE WESTERN LAKE ONTARIO  
NEARSHORES FOR SUNDAY. ANOTHER, STRONGER STORM SYSTEM MAY BRING  
ANOTHER ROUND OF THUNDERSTORMS EARLY NEXT WEEK, WITH HIGH END  
SMALL CRAFT CONDITIONS LIKELY RETURNING ON THE LAKES BY TUESDAY.  
 

 
   
TIDES/COASTAL FLOODING
 
 
EAST TO NORTHEAST WINDS WILL INCREASE LATE TONIGHT AND SUNDAY,  
WITH WAVES BUILDING ACROSS WESTERN PORTIONS OF LAKE ONTARIO.  
THIS COMBINED WITH ALREADY HIGH LEVELS ON LAKE ONTARIO HAS THE  
POTENTIAL TO RESULT IN LAKESHORE FLOODING ALONG THE SHORELINE.  
THERE IS STILL UNCERTAINTY CONCERNING THE PLACEMENT OF THE  
HIGHEST WAVE HEIGHTS SINCE EVEN A SLIGHT SHIFT TO THE MORE  
EASTERLY DIRECTION WOULD PUSH THE HIGHEST WAVES TO THE CANADIAN  
SHORELINE. A LAKESHORE FLOOD WATCH IS IN EFFECT FOR NIAGARA AND  
ORLEANS COUNTIES.  
 

 
   
CLIMATE
 
 
THE LAST DAYS OF APRIL WILL FINISH WITH ABOVE NORMAL TEMPERATURES,  
WARM ENOUGH THAT IT WILL SEND OUR CLIMATE SITES TOWARDS A TOP 5  
TO 10 WARMEST APRIL ON RECORD. BELOW ARE THE WARMEST APRILS ON  
RECORD.  
 
BUFFALO  
 
RANK....VALUE (F).....YEAR  
 
1........51.3.........1921  
2........51.1.........2010  
3........51.0.........1955  
4........50.9.........2008  
5........50.8.........1878  
 
CURRENT APRIL AVERAGE TEMPERATURE THROUGH APRIL 28TH: 50.4F  
 
ROCHESTER  
 
RANK....VALUE (F).....YEAR  
 
1........52.6.........1878  
2........52.5.........1921  
3........52.4.........2010  
4........52.3.........2008  
5........51.4.........1915  
 
CURRENT APRIL AVERAGE TEMPERATURE THROUGH APRIL 28TH: 51.5F  
 
WATERTOWN  
 
RANK....VALUE (F).....YEAR  
 
1........49.1.........1987  
2........48.7.........1955  
3........48.7.........2010  
4........48.3.........1968  
5........48.2.........2008  
 
CURRENT APRIL AVERAGE TEMPERATURE THROUGH APRIL 28TH: 47.6F  
 
TEMPERATURE RECORDS FOR BUFFALO AND ROCHESTER BEGIN 1871, WHILE  
WATERTOWN'S HISTORY IS A BIT SHORTER, WITH TEMPERATURE RECORDS  
BEGINNING IN 1949.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...LAKESHORE FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY  
EVENING FOR NYZ001-002.  
MARINE...SMALL CRAFT ADVISORY FROM 4 AM SUNDAY TO 2 AM EDT MONDAY FOR  
LOZ042-043.  
 

 
 

 
 
SYNOPSIS...APFFEL  
NEAR TERM...APFFEL  
SHORT TERM...THOMAS  
LONG TERM...HITCHCOCK  
AVIATION...APFFEL  
MARINE...APFFEL/TMA  
TIDES/COASTAL FLOODING...APFFEL/TMA  
CLIMATE...THOMAS  
 
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