981  
FXUS61 KBUF 231144  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
644 AM EST MON JAN 23 2017  
   
SYNOPSIS
 
 
A LARGE LOW PRESSURE SYSTEM OVER THE MID ATLANTIC WILL CHURN  
NORTHWARD ALONG THE EAST COAST TODAY AND TONIGHT BRINGING WIDESPREAD  
PRECIPITATION. THIS WILL START AS RAIN TODAY AND CHANGE TO SNOW  
TONIGHT WITH PORTIONS OF CENTRAL NY RECEIVING SIGNIFICANT SNOW  
ACCUMULATIONS. COLDER AIR WILL THEN SLOWLY FILTER INTO THE REGION  
INTO WEEKEND WITH LAKE EFFECT SNOWS INCREASING EAST OF THE LOWER  
GREAT LAKES.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
...SIGNIFICANT SNOWFALL EXPECTED FOR CENTRAL NY TONIGHT INTO  
TUESDAY...  
 
A LARGE LOW PRESSURE SYSTEM SEEN ON WV IMAGERY THIS MORNING ACROSS  
THE SOUTHEAST WILL MOVE NORTHWARD THROUGH THE MID ATLANTIC TODAY AND  
TONIGHT AND FINALLY OFF THE NEW ENGLAND COAST ON TUESDAY. THE RESULT  
IS A HIGH CONFIDENCE FORECAST IN WIDESPREAD PRECIPITATION ACROSS THE  
REGION FROM TODAY THROUGH TONIGHT AND INTO TUESDAY MORNING. HOWEVER,  
THERE STILL REMAINS LOWER CONFIDENCE IN THE PRECIPITATION TYPE AND  
SNOW ACCUMULATIONS DUE TO VERY MARGINAL THERMAL PROFILES.  
 
THE SYNOPTIC DYNAMICS ARE VERY FAVORABLE FOR WIDESPREAD PRECIPITATION  
ACROSS WESTERN AND CENTRAL NY. UPPER LEVEL DIFFLUENCE AHEAD OF THE  
500 MB LOW COUPLED WITH AMPLE ATLANTIC MOISTURE FLUX CONVERGENCE  
INTO THE REGION ON THE ANOMALOUSLY STRONG EASTERLY FLOW INTO NY STATE  
WILL PRODUCE WIDESPREAD PRECIPITATION. HIGHEST QPF AMOUNTS AROUND AN  
INCH ARE LIKELY THROUGH MUCH OF CENTRAL NY NEAR THE NOSE OF BEST  
MOISTURE ADVECTION, FROM ALLEGANY COUNTRY THROUGH THE FINGER LAKES  
TOWARD THE TUG HILL. QPF AMOUNTS ARE EXPECTED TO TAPER OFF TO AROUND  
A HALF INCH ACROSS THE NIAGARA FRONTIER AND THE SAINT LAWRENCE  
VALLEY.  
 
AGAIN, THE CHALLENGING PART OF THIS FORECAST REMAINS THE VERY  
MARGINAL THERMAL PROFILES. THIS EVENT WILL START AS ALL RAIN ACROSS  
THE REGION TODAY. HOWEVER, AS WE GET INTO THE LATER PART OF THE  
AFTERNOON AND THIS EVENING, MARGINALLY COOLER AIR WILL BE ADVECTED  
IN ON THE EASTERLY FLOW FROM THE COOLER AIRMASS OVER NEW ENGLAND.  
THIS, COMBINED WITH INCREASING PRECIPITATION RATES BY THIS EVENING,  
WILL ALLOW FOR DYNAMICALLY COOLING TO FURTHER COOL THE COLUMN AND  
SUPPORT A CHANGE OVER FROM RAIN TO POSSIBLY SOME WINTRY MIX AND THEN  
OVER TO SNOW TONIGHT. THIS IS THE TRICKY PART OF THE FORECAST. THE  
VARIOUS MODEL GUIDANCES RANGE FROM EASILY COLD ENOUGH TO SUPPORT ALL  
SNOW, TO SOME WITH STUBBORN WARM NOSES ALOFT THAT WOULD SUPPORT  
SLEET OR EVEN FREEZING RAIN. EXPECT THAT DYNAMICAL COOLING IN THE  
HIGH PRECIPITATION RATES, SOMETHING THE MODELS USUALLY DO NOT  
CAPTURE WELL ENOUGH, WILL BE ENOUGH TO PUSH THE PROFILE COLD ENOUGH  
TO SUPPORT ALL SNOW. HAVE THUS LEVERAGED THE COLDER EC/CANADIAN  
SOLUTIONS TO SUPPORT HIS CHANGE OVER TO ALL SNOW TONIGHT. SNOWFALL  
AMOUNTS WILL BE HIGHEST ACROSS CENTRAL NY WHERE THE BEST FORCING,  
AND HIGHEST QPF WILL TRACK, AND THUS THIS IS WHERE CONFIDENCE WAS  
HIGH ENOUGH FOR A WINTER STORM WARNING. SNOWFALL AMOUNTS HERE WILL  
MOST LIKELY RANGE FROM 6 TO 10 INCHES. SNOWFALL RATES IN THE WARNING  
AREA WILL LIKELY PEAK AROUND AN INCH PER HOUR, WITH MOST OF THE SNOW  
COMING IN A 6 TO 10 HOUR WINDOW. ON THE NORTHWEST PERIPHERY OF THIS  
WARNING, LOWER QPF AMOUNTS WILL AMOUNT TO ADVISORY SNOW  
ACCUMULATIONS OF 4 TO 7 INCHES. AMOUNTS WILL BE LOWEST ACROSS THE  
FAR WESTERN NY, WHICH WILL SEE THE LEAST QPF AND LEAST FAVORABLE  
DYNAMICAL COOLING, WITH TOTALS OF 1 TO 4 INCHES. THUS HAVE EXCLUDED  
FAR WESTERN NY FROM ANY HIGHLIGHTS AT THIS TIME.  
 
ALL THAT SAID, SNOWFALL ACCUMULATIONS WILL BE VERY SENSITIVE TO HOW  
QUICKLY WE CAN MAKE THE TRANSITION FROM RAIN TO SNOW. IF THIS OCCURS  
MORE SLOWLY THAN FORECAST, OR IF MORE OF A MIX OF SNOW AND SLEET  
OCCURS, THEN THE TOTALS WILL OVERALL BE LOWER, SOMETHING THAT IS  
CERTAINLY POSSIBLE.  
 
ON TUESDAY, SNOW WILL TAPER OFF FROM WEST TO EAST. SNOW WILL LIKELY  
END ACROSS WESTERN NY BY MID MORNING ON TUESDAY, BUT WILL LIKELY  
LINGER ACROSS THE NORTH COUNTRY THROUGH TUESDAY AFTERNOON.  
 
TEMPERATURES THROUGHOUT THIS EVENT WILL INDEED BE VERY MARGINAL.  
HIGHS THIS AFTERNOON WILL BE IN THE UPPER 30S TO LOWER 40S, AND WILL  
ONLY FALL TO RIGHT AROUND THE FREEZING MARK TONIGHT. TEMPERATURES  
WILL RECOVER VERY LITTLE ON TUESDAY, REMAIN NEARLY STEADY NEAR THE  
FREEZING MARK.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
 
 
TUESDAY NIGHT THE COMPLEX AND STRONG LOW PRESSURE WILL MOVE FROM THE  
GULF OF MAINE INTO THE CANADIAN MARITIMES. WRAP AROUND MOISTURE AND  
CYCLONIC FLOW WILL LINGER ACROSS THE EASTERN LAKE ONTARIO REGION  
TUESDAY EVENING WITH A FEW MORE SNOW SHOWERS, ESPECIALLY ACROSS  
HIGHER TERRAIN WITH AN UPSLOPE FLOW COMPONENT. ANY ADDITIONAL  
ACCUMULATIONS WILL BE VERY MINOR (LESS THAN AN INCH). THIS WILL END  
OVERNIGHT AS THE DEEPER MOISTURE PULLS AWAY. OTHERWISE THE REST OF  
THE AREA WILL REMAIN DRY AS A WEAK RIDGE AXIS BRIEFLY BUILDS ACROSS  
THE LOWER GREAT LAKES.  
 
ON WEDNESDAY A POTENT MID LEVEL CLOSED LOW AND ASSOCIATED SURFACE  
LOW WILL MOVE INTO THE CENTRAL GREAT LAKES, WITH A DOWNSTREAM WARM  
FRONT MOVING NORTHEAST ACROSS OUR AREA. MODEL GUIDANCE HAS TRENDED  
NORTH AND WEST WITH THE STRONGER ISENTROPIC ASCENT AND DEEPER  
MOISTURE ALONG THE WARM FRONT, WHICH WILL INITIALLY LESSEN PRECIP  
CHANCES ACROSS OUR AREA THROUGH WEDNESDAY MORNING. BY LATER IN THE  
DAY DPVA WILL INCREASE AHEAD OF THE STRONG MID LEVEL LOW, BRINGING  
AN INCREASING CHANCE OF RAIN SHOWERS ESPECIALLY ACROSS WESTERN NY  
AND THE EASTERN LAKE ONTARIO REGION. WARM ADVECTION WILL PUSH  
TEMPERATURES INTO THE LOWER TO MID 40S FOR MUCH OF THE AREA, WITH  
MID TO UPPER 30S ACROSS THE NORTH COUNTRY.  
 
WEDNESDAY NIGHT AND THURSDAY THE POTENT MID LEVEL CLOSED LOW OVER  
THE CENTRAL GREAT LAKES WILL OPEN UP AND ACCELERATE EAST DOWN THE  
SAINT LAWRENCE VALLEY AS IT MERGES WITH ANOTHER TROUGH CROSSING  
HUDSON BAY. LOW LEVEL COLD ADVECTION WILL BEGIN WEDNESDAY NIGHT,  
THEN INCREASE LATER THURSDAY AS A SECONDARY SURFACE TROUGH MOVES  
SOUTHEAST ACROSS THE AREA. THE PASSAGE OF THE MID LEVEL TROUGH AND  
ASSOCIATED LARGE SCALE ASCENT WILL SUPPORT INCREASING COVERAGE OF  
PRECIP WEDNESDAY NIGHT AND THURSDAY, WITH THE GREATEST AMOUNTS EAST  
OF BOTH LAKES WITH FRICTIONAL CONVERGENCE AND UPSLOPE FLOW INTO THE  
HIGHER TERRAIN. IT WILL BECOME MARGINALLY COLD ENOUGH FOR SOME LAKE  
ENHANCEMENT EAST OF THE LAKES BY THURSDAY, THOUGH NOT COLD ENOUGH  
FOR PURE LAKE EFFECT YET.  
 
PRECIP TYPE WILL BE MAINLY RAIN WEDNESDAY EVENING, THEN SLOWLY MIX  
WITH WET SNOW FIRST ACROSS THE HIGHER TERRAIN AND LAST ON THE LAKE  
PLAINS OVERNIGHT. DURING THE DAY THURSDAY EXPECT MAINLY WET SNOW  
ACROSS THE HIGH TERRAIN, WITH A MIX OF RAIN AND WET SNOW AT LOWER  
ELEVATIONS. THE MARGINAL TEMPERATURES WILL PRODUCE ELEVATION  
DEPENDENT SNOW AMOUNTS, WITH A FEW INCHES LIKELY ACROSS THE HIGHER  
TERRAIN EAST OF BOTH LAKES AND VERY LITTLE AT LOWER ELEVATIONS  
THROUGH LATE AFTERNOON THURSDAY.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
 
 
TYPICAL MID WINTER WEATHER WILL BECOME ESTABLISHED AGAIN THROUGH THE  
LONG TERM PERIOD AFTER A SEVERAL WEEK HIATUS. A FUNDAMENTAL PATTERN  
CHANGE WILL TAKE PLACE ACROSS NORTH AMERICA, WITH A RIDGE BUILDING  
OVER THE WEST AND A LONGWAVE TROUGH BECOMING ESTABLISHED OVER THE  
EASTERN HALF OF THE CONTINENT LATE IN THE WEEK THROUGH NEXT WEEKEND.  
 
OUR AREA WILL BE IN THE ACTIVE REGION NEAR THE BASE OF THE LONGWAVE  
TROUGH, WITH NUMEROUS WEAK SHORTWAVES MOVING THROUGH THE BASE OF THE  
TROUGH. EACH OF THESE SHORTWAVES MAY PRODUCE A FEW LIGHT SNOW  
SHOWERS ACROSS MUCH OF THE REGION, AND WILL ALSO BRING SUBTLE  
VARIATIONS TO THE LOW LEVEL FLOW, MOISTURE DEPTH, AND COLD AIR  
STRUCTURE WHICH WILL IMPACT ONGOING LAKE EFFECT SNOW.  
 
THE PATTERN APPEARS FAVORABLE FOR A LONG PERIOD OF LAKE EFFECT SNOW  
STARTING THURSDAY NIGHT AND GOING RIGHT THROUGH THE ENTIRE WEEKEND.  
MODEL GUIDANCE IS IN GOOD AGREEMENT INITIALLY FROM THURSDAY NIGHT  
THROUGH FRIDAY NIGHT WITH MEAN LOW LEVEL FLOW FROM THE WNW. THIS  
WOULD TARGET THE WESTERN SOUTHERN TIER OFF LAKE ERIE AND THE  
SOUTHERN TUG HILL AND OSWEGO COUNTY OFF LAKE ONTARIO, POSSIBLY INTO  
PORTIONS OF NORTHERN CAYUGA AND NE WAYNE COUNTIES AT TIMES. BY  
SATURDAY AND SUNDAY MODEL GUIDANCE BEGINS TO SHOW SOME SPREAD, WITH  
THE GFS MAINTAINING WNW FLOW WHILE THE ECMWF BACKS FLOW MORE TO THE  
WSW. SUBTLE SHORTWAVES WILL LIKELY PRODUCE SOME VARIATION IN LOW  
LEVEL FLOW, ALTHOUGH THE DETAILS ARE ALWAYS UNCERTAIN AT THIS TIME  
RANGE.  
 
THE AIRMASS IS NOT OVERLY COLD BY LATE JANUARY STANDARDS, WITH 850MB  
TEMPS STARTING AT AROUND -8C THURSDAY NIGHT AND DROPPING TO AROUND  
-12C OVER THE WEEKEND. TEMPERATURES ARE FAIRLY COLD AT 700MB  
HOWEVER, AND THIS COMBINED WITH DEEP MOISTURE WILL ALLOW LAKE  
INDUCED EQUILIBRIUM LEVELS TO RISE TO NEAR 10K FEET. THE FAVORABLE  
INSTABILITY AND LONGEVITY OF THE SETUP SUGGEST SIGNIFICANT  
ACCUMULATIONS ARE POSSIBLE EAST OF THE LAKES.  
 

 
   
AVIATION /12Z MONDAY THROUGH FRIDAY/
 
 
NORTHEAST FLOW OFF LAKE ONTARIO WITH PLENTIFUL LOW LEVEL MOISTURE  
WILL MAINTAIN LOW IFR STRATUS AROUND 300 FEET AT KBUF/KIAG/KROC  
THROUGH SUNRISE MONDAY BEFORE IMPROVEMENT WITH DAYTIME MIXING.  
 
TODAY A STORM SYSTEM WILL BRING A PERIOD OF RAIN TO THE REGION.  
EXPECT RAIN TO REACH THE SOUTHERN TIER AROUND DAYBREAK, KIAG, KBUF,  
KROC JUST AFTER NOONTIME, AND KART BY LATE AFTERNOON. THOUGH  
CONDITIONS MAY IMPROVE TO MVFR/VFR BRIEFLY BEFORE THE RAIN, WITHIN  
THE RAIN, EXPECT A DETERIORATION BACK TO IFR AND MVFR FLIGHT  
CONDITIONS. RAIN WILL TRANSITION TO A WINTRY MIX AND THEN SNOW THIS  
EVENING AND OVERNIGHT. THE HEAVIEST SNOW WILL FALL ACROSS CENTRAL  
NY, FROM ELZ TO FZY WHERE VSBY TO A QUARTER MILE IS EXPECTED.  
OTHERWISE, LIGHT TO MODERATED SNOW WILL FALL AT MOST TAF SITES  
OVERNIGHT, WITH VSBY 2 MILES TO 1/2 MILE AT TIME, ALONG WITH IFR  
CIGS/  
 
OUTLOOK...  
 
TUESDAY...AREAS OF MVFR/IFR WITH WET SNOW MIXED WITH RAIN.  
WEDNESDAY AND THURSDAY...VFR/MVFR WITH A CHANCE OF RAIN AND SNOW.  
FRIDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.  
 

 
   
MARINE
 
 
SMALL CRAFT CONDITIONS WILL CONTINUE ON THE SOUTH CENTRAL AND SOUTH  
WEST SHORELINE OF LAKE ONTARIO AS EAST-NORTHEAST WINDS 20 TO 25  
KNOTS PERSIST INTO TUESDAY AS A STRONG LOW PRESSURE SYSTEM TRACKS UP  
THE EAST COAST. WINDS AND WAVES WILL REMAIN ELEVATED UNTIL THE LOW  
PRESSURE SYSTEM PASSES ON TUESDAY. LAKE ERIE REMAINS LESS OF A  
CONCERN AS WAVE ACTION WILL DIRECTED AWAY FROM THE EASTERN END OF  
THE LAKE.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST  
TUESDAY FOR NYZ007.  
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST  
TUESDAY FOR NYZ005-006-008.  
WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 10 AM EST  
TUESDAY FOR NYZ004-013-014-021.  
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM EST  
TUESDAY FOR NYZ003-011-012-020.  
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR LOZ042-043.  
SMALL CRAFT ADVISORY FROM 4 AM TO 1 PM EST TUESDAY FOR  
LOZ044.  
 

 
 

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