600  
FXUS61 KBUF 190221  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1021 PM EDT SAT APR 18 2015  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL REMAIN IN CONTROL TONIGHT AND SUNDAY...BRINGING  
MAINLY CLEAR SKIES AND MILD TEMPERATURES TO THE REGION THROUGH THE  
DAYLIGHT HOURS ON SUNDAY. BY SUNDAY NIGHT A SERIES OF LOW PRESSURE  
SYSTEMS MOVING OUT OF THE PLAINS STATES WILL BRING PERIODS OF  
RAINFALL FOR SUNDAY NIGHT THROUGH TUESDAY. SOME RUMBLES OF THUNDER  
ARE ALSO POSSIBLE ON MONDAY ACROSS WESTERN NEW YORK. THE REST OF  
THE WORK WEEK WILL SEE BELOW NORMAL TEMPERATURES AND PERIODS OF  
UNSETTLED WEATHER AS AN UPPER-LEVEL LOW REMAINS IN CONTROL.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
VISIBLE SATELLITE IMAGERY SHOWING CLEAR SKIES LATE THIS EVENING  
EXCEPT FOR A FEW THIN CIRRUS BRUSHING THE WESTERN SOUTHERN TIER. A  
SOMEWHAT THICKER AREA OF CIRRUS OVER WESTERN AND CENTRAL LAKE ERIE  
WILL DRIFT INTO WESTERN NY OVER THE NEXT FEW HOURS...BUT SHOULD THIN  
AS IT ENCOUNTERS DRY AIR AND SUBSIDENCE.  
 
HIGH PRESSURE WILL BUILD ACROSS THE REGION TONIGHT INTO SUNDAY AS  
THE CORE OF THE SURFACE HIGH SLIDES ACROSS ONTARIO INTO QUEBEC.  
NORTH WINDS WILL QUICKLY DIMINISH THIS EVENING WITH THE LOSS OF  
DAYTIME MIXING. THE LIGHT NORTHERLY WINDS OVERNIGHT WILL SLOWLY TURN  
EASTERLY TO SOUTHEASTERLY THROUGH THE DAY SUNDAY AS THE CENTER OF  
THE SURFACE MOVES TO THE EAST OF THE FORECAST AREA.  
 
TEMPERATURES TONIGHT WILL COOL QUICKLY WITH SOME WEAK COLD AIR  
ADVECTION THROUGH THE FIRST PART OF THE EVENING...THEN LIGHT WINDS  
AND CLEAR SKIES WILL ALLOW FOR EFFICIENT RADIATIONAL COOLING THROUGH  
THE EARLY MORNING. TEMPERATURES FOR MOST LOCATIONS WILL BOTTOM OUT  
IN THE 30S...MAKING FOR A CRISP START TO THE DAY ON SUNDAY MORNING.  
AS THE WINDS BECOME INCREASING SOUTHEASTERLY BY SUNDAY AFTERNOON...  
AND WEAK WARM ADVECTION BECOMES ESTABLISHED...TEMPERATURES WILL  
RECOVER INTO THE 60S FOR MANY LOCATIONS AS 850 MB TEMPERATURES  
RETURN TO +4 TO +6C. THIS WIND DIRECTION SHOULD KEEP DOWNTOWN  
BUFFALO FROM BEING INFLUENCED BY THE LAKE BREEZE. HOWEVER...THE  
SOUTH SHORE OF LAKE ONTARIO WILL BE KEPT CONSIDERABLY COOLER BY THE  
GRADIENT ONSHORE FLOW.  
 
CLOUD COVER WILL START TO INCREASE FROM SOUTHWEST TO NORTHEAST LATE  
IN THE DAY SUNDAY...AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. BUT  
MORE ON THIS WILL BE DISCUSSED IN THE SHORT TERM.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
 
 
THIS EVENING AN UPPER LEVEL LOW SPIRALS OVER THE FOOTHILLS OF THE  
ROCKIES...AND THIS FEATURE WILL GUIDE A STORM SYSTEM ACROSS OUR  
AREA.  
 
THROUGH THE DAY ON SUNDAY DEEP MOISTURE WILL BE STREAMING NORTHWARD  
FROM THE GULF OF MEXICO. THIS MOISTURE WILL FEED A PERIOD OF  
RAIN...WHICH WILL DEVELOP ACROSS THE EASTERN GREAT LAKES SUNDAY  
NIGHT. AT THE SURFACE SUNDAY EVENING AN AREA OF LOW PRESSURE WILL BE  
FOUND OVER THE MIDWEST...WITH A WARM FRONT EXTENDING EASTWARD ACROSS  
THE OHIO VALLEY AND TOWARDS WEST VIRGINIA. THIS LOW PRESSURE WILL  
DEEPEN AS THE AFOREMENTIONED UPPER LEVEL LOW NEARS...WITH BOTH  
FEATURES ADVANCING NORTHWARD AHEAD OF A DEEPER AND MORE POTENT UPPER  
LEVEL TROUGH OF LOW PRESSURE.  
 
STRONG LOW LEVEL CONVERGENCE FROM A 65 TO 70 KNOT LLJ CENTERED NEAR  
850 TO 900 HPA SUNDAY NIGHT WILL BRING LIFT ACROSS THE WARM  
FRONT...SUCH THAT WIDESPREAD RAIN FALL UPON THE REGION. A  
QUARTER TO HALF INCH OF RAINFALL IS EXPECTED SUNDAY NIGHT AND INTO  
MONDAY MORNING FROM THIS SYSTEM. THERE IS HIGH CONFIDENCE IN  
RAINFALL SUNDAY NIGHT DUE TO THE DEEPER MOISTURE AND UPWARD FORCING  
ALONG THE WARM FRONT.  
 
THERE WILL BE GUSTY WINDS THIS TIME PERIOD AS WELL. A SOUTHEAST WIND  
WILL INCREASE IN SPEED NEAR THE LAKE ERIE SHORELINE AS IT  
ACCELERATES DOWNWARD FROM THE HILLS OF SW NYS. SURFACE GUSTS 30 TO  
40 KNOTS ARE POSSIBLE ALONG THE LAKE ERIE SHORELINE...INCLUDING  
ACROSS THE NYS THRUWAY AND ROUTE 5 SUNDAY NIGHT. AS THE WARM FRONT  
AND ASSOCIATED RAIN LIFTS NORTHWARD OUT OF THE REGION EARLY  
MONDAY...THERE IS THE POTENTIAL FOR LIMITED SUNSHINE ALONG WITH A  
BRIEF WINDOW OF RAINFREE CONDITIONS. WITH THE LLJ STILL  
OVERHEAD...ANY SUNSHINE WILL INCREASE THE MIXING HEIGHTS SUCH THAT  
WE COULD TAP INTO THIS LLJ...WITH WIND GUSTS MONDAY ALSO 30 TO 35  
KNOTS ACROSS WESTERN AND NORTH CENTRAL NEW YORK.  
 
LATER MONDAY AFTERNOON CLOUDS WILL THICKEN FROM WEST TO EAST...AND A  
DECREASE IN THE GUSTY WINDS IS EXPECTED. A COLD FRONT FROM THIS  
CENTRAL LAKES STORM SYSTEM WILL NEAR WESTERN NEW YORK LATE MONDAY  
AFTERNOON. ANOTHER ROUND OF RAIN SHOWERS IS EXPECTED MONDAY  
AFTERNOON AND MONDAY NIGHT ALONG AND AHEAD OF THE COLD FRONT. THERE  
WILL BE SLIGHTLY LESS CONFIDENCE FOR RAINFALL WITH THIS COLD FRONT  
DUE TO THE CONVECTIVE NATURE OF THE SHOWERS MONDAY NIGHT. THIS  
RAINFALL EVENT WILL AVERAGE AROUND A QUARTER OF AN INCH...WITH A  
GREATER RANGE IN RAIN REPORTS EXPECTED ACROSS THE REGION DUE TO THE  
CONVECTIVE NATURE. WILL CONTINUE TO MENTION THUNDER FOR AREAS SOUTH  
OF LAKE ONTARIO MONDAY NIGHT ALONG THE COLD FRONT WITH THE SMALL  
AMOUNT OF CAPE VALUES PRESENT.  
 
TUESDAY THERE WILL CONTINUE TO BE CHANCES FOR SHOWERS AS THE UPPER  
LEVEL LOW NEARS THE REGION. SOME INCREASE IN SHOWERS IS EXPECTED  
TUESDAY AFTERNOON WITH DIURNAL HEATING INCREASING MID LEVEL LAPSE  
RATES. EXPECT ANOTHER BREEZY DAY TUESDAY ACROSS WNY WITH THE  
STRONGEST BREEZE SE OF LAKE ERIE. WINDS SHOULD BE A LITTLE LIGHTER  
EAST OF LAKE ONTARIO WHICH WILL TO THE NORTHEAST AND FARTHER AWAY  
FROM A PV INTRUSION.  
 
THE WARMEST DAY THIS PERIOD WILL BE MONDAY WHEN BEFORE THE COLD  
FRONT 850 HPA TEMPERATURES WILL SURGE TO +7 TO +10C. THESE READINGS  
WILL SUPPORT HIGHS IN THE 60S...WITH 70S POSSIBLE ACROSS LOWER  
ELEVATIONS ON A SOUTHEAST WIND. BEHIND THE COLD FRONT TUESDAY WILL  
BE COOLER BY SOME 10 TO 15 DEGREES.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
 
 
CLASSIC SPRING-TIME PATTERN CONTINUES THIS TIME PERIOD AS A  
DEVELOPING NEGATIVE NAO ALLOWS FOR A UPPER LEVEL CUT OFF LOW TO  
STALL OVER EASTERN CANADA AND THE NORTHEAST UNITED STATES. UNDER  
THIS LOW PRESSURE EXPECT CLOUDY DAYS WITH SCATTERED RAIN SHOWERS.  
RAIN SHOWER ACTIVITY WILL BE MOST PRONOUNCED IN THE AFTERNOON HOURS  
WITH DAYTIME HEATING...WITH FEW SHOWERS TO BE FOUND BY NIGHT. THERE  
MAY EVEN BE SOME WET SNOW MIXING IN AT NIGHT ACROSS THE REGION.  
DAYTIME AIR TEMPERATURES WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL.  
 
THIS CUT OFF LOW WILL SLOWLY MEANDER EASTWARD...SUCH THAT SOME  
IMPROVEMENT IN BOTH TEMPERATURES AND PRECIPITATION IS POSSIBLE FOR  
FRIDAY AND SATURDAY...THOUGH WILL MAINTAIN AT LEAST LOW CHC POPS IN  
THE GRIDS.  
 

 
   
AVIATION /03Z SUNDAY THROUGH THURSDAY/
 
 
VFR CONDITIONS WILL PREVAIL THROUGH THE 00Z TAF CYCLE. HIGH PRESSURE  
WILL BUILD EAST ACROSS QUEBEC TONIGHT WITH A RIDGE EXTENDING DOWN  
INTO THE LOWER LAKES REGION. THIS WILL PROVIDE SKC IN MOST AREAS  
WITH JUST SOME HIGH/THIN CIRRUS SKIRTING AREAS NEAR THE PA STATE  
LINE.  
 
HIGH CLOUDS WILL OVERSPREAD THE ENTIRE REGION LATER SUNDAY AS WARM  
ADVECTION AND MOISTURE INCREASE AHEAD OF A POTENT SYSTEM LIFTING OUT  
OF THE LOWER OHIO VALLEY. THE RAIN ASSOCIATED WITH THIS SYSTEM  
SHOULD ENTER THE SOUTHWEST CORNER OF THE STATE NEAR KJHW AROUND OR  
SHORTLY AFTER 00Z MON.  
 
OUTLOOK...  
SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND  
GUSTY WINDS.  
TUESDAY THROUGH THURSDAY...VFR/MVFR WITH SCATTERED SHOWERS.  
 

 
   
MARINE
 
 
NORTHWEST WINDS WILL DIMINISH QUICKLY THIS EVENING AS HIGH PRESSURE  
BUILDS EAST ACROSS QUEBEC AND THE PRESSURE GRADIENT RELAXES. CHOPPY  
CONDITIONS ALONG THE SOUTH SHORE OF LAKE ONTARIO WILL IMPROVE  
OVERNIGHT...AND WINDS OVER THE SAINT LAWRENCE VALLEY WILL DIMINISH.  
 
ON SUNDAY...THE SFC PRESSURE GRADIENT WILL INTENSIFY OVER THE LOWER  
GREAT LAKES AS THE SFC HIGH WILL MOVE EAST AND A COMPLEX STORM  
SYSTEM WILL APPROACH FROM THE MID WEST. THIS WILL RESULT IN  
FRESHENING EASTERLY WINDS...PARTICULARLY ON LAKE ONTARIO...FOR WHICH  
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR WESTERN LAKE ONTARIO  
DURING THE DAY SUNDAY.  
 
FRESH TO STRONG SOUTHEASTERLIES WILL BE FOUND ON LAKES ERIE AND  
ONTARIO SUNDAY NIGHT AS AN INTENSIFYING STORM SYSTEM WILL PUSH NORTH  
ACROSS MICHIGAN. SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR ALL OF  
LAKE ONTARIO...EASTERN LAKE ERIE AND THE UPPER NIAGARA RIVER FOR  
SUNDAY NIGHT THROUGH MONDAY.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 10 PM SUNDAY TO NOON EDT MONDAY FOR  
LEZ040-041.  
SMALL CRAFT ADVISORY FROM 11 PM SUNDAY TO 11 AM EDT MONDAY  
FOR LEZ020.  
SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 8 PM EDT  
MONDAY FOR LOZ042-043.  
SMALL CRAFT ADVISORY FROM 8 PM SUNDAY TO 11 PM EDT MONDAY  
FOR LOZ044-045.  
 

 
 

 
 
SYNOPSIS...CHURCH  
NEAR TERM...CHURCH/HITCHCOCK  
SHORT TERM...THOMAS  
LONG TERM...THOMAS  
AVIATION...HITCHCOCK  
MARINE...CHURCH/HITCHCOCK  
 
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