349  
FXUS61 KBUF 140608  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
108 AM EST THU DEC 14 2017  
   
SYNOPSIS
 
 
A WEAK AREA OF LOW PRESSURE WILL BRING A PERIOD OF SNOW TO MOST OF  
WESTERN NEW YORK TONIGHT. FOLLOWING A BRIEF BREAK MID-DAY THURSDAY  
ANOTHER SYSTEM WILL BRING MORE LAKE EFFECT SNOW TO SOME AREAS FRIDAY  
AND SATURDAY. MEANWHILE IT WILL CONTINUE TO BE COLD WITH HIGHS IN  
THE TEENS THURSDAY.  
 

 
   
NEAR TERM /THROUGH TODAY/
 
 
LOW PRESSURE IS LOCATED OVER NORTHEAST OHIO TONIGHT. LIGHT SNOW HAS  
BEEN ONGOING ACROSS THE FORECAST AREA AND WILL CONTINUE OVERNIGHT. A  
WINTER WEATHER ADVISORY IS IN EFFECT FOR THE SOUTHERN TIER WHERE AN  
ADDITIONAL ONE OR TWO INCHES CAN BE EXPECTED INTO THURSDAY MORNING.  
ELSEWHERE, LESS THAN AN INCH OF ACCUMULATION IS EXPECTED. AS THE LOW  
MOVES INTO PA OVERNIGHT SNOW WILL TAPER OFF FROM NORTH TO SOUTH.  
LIGHT NORTH-NORTHEASTERLY WINDS WILL CONTINUE OVERNIGHT WITH LOW  
TEMPERATURES REACHING THE LOW TEENS.  
 
THE CLIPPER WILL MOVE AWAY QUICKLY ON THURSDAY, WITH DRIER AIR  
BEHIND THE SYSTEM CAUSING LAKE EFFECT SNOWS TO TEMPORARILY TAPER OFF  
DURING THE MIDDLE PORTION OF THE DAY. ANOTHER SHORTWAVE WILL  
APPROACH LATE IN THE DAY WITH LAKE SNOWS EXPECTED TO REDEVELOP NEAR  
THE CHAUTAUQUA RIDGE AND SOUTHEAST OF LAKE ONTARIO CENTERED BETWEEN  
SODUS AND OSWEGO.  
 
OTHERWISE, TEMPERATURES WILL BE MUCH BELOW NORMAL. EVEN THOUGH  
CLOUDS AND WINDS WILL LIMIT RADIATIONAL COOLING TONIGHT, LOWS WILL  
MAINLY RANGES FROM THE SINGLE DIGITS TO LOWER TEENS. ANY CLEARING  
COULD ALLOW BELOW ZERO READINGS ACROSS THE NORTH COUNTRY. HIGHS ON  
THURSDAY WILL BE MAINLY IN THE TEENS, WITH LOWER 20S ALONG THE  
IMMEDIATE LAKESHORES.  
 

 
   
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/
 
 
THURSDAY NIGHT THROUGH FRIDAY LAKE EFFECT SNOW WILL CONTINUE  
SOUTHEAST OF LAKES ERIE AND ONTARIO.  
 
OFF LAKE ERIE...  
 
LAKE INDUCED EQUILIBRIUM LEVELS WILL BE RELATIVELY LOW, AT ABOUT 8K  
FEET. THIS WILL YIELD A SHALLOW, BUT SUFFICIENT LAYER OF DENDRITIC  
CRYSTAL GROWTH. GIVEN THE MARGINAL MOISTURE AND CLOUD DEPTH, LAKE  
EFFECT SNOW SHOULD REMAIN RATHER LIGHT IN NATURE. DURING THURSDAY  
EVENING IT WILL STILL BE LOCATED ACROSS THE WESTERN SOUTHERN TIER  
WITH WNW FLOW. LATE THURSDAY NIGHT AND FRIDAY MORNING BOUNDARY LAYER  
FLOW WILL QUICKLY BACK TO THE SOUTHWEST AHEAD OF THE NEXT CLIPPER,  
CARRYING LAKE EFFECT SNOW NORTHWARD ACROSS ERIE COUNTY. THIS BAND  
WILL CROSS BUFFALO DURING THE EARLY TO MID MORNING BEFORE ENDING UP  
IN NIAGARA COUNTY BY MIDDAY. SNOWFALL AMOUNTS WILL BE LIGHT, WITH 1-  
3 INCHES ACROSS THE WESTERN SOUTHERN TIER AND THE BUFFALO AREA.  
 
OFF LAKE ONTARIO...  
 
A BAND OF LAKE EFFECT SNOW OVER NORTHERN CAYUGA AND OSWEGO COUNTIES  
THURSDAY EVENING WILL MOVE A LITTLE FARTHER NORTHEAST OVERNIGHT INTO  
THE CENTRAL PORTION OF OSWEGO COUNTY, AND EVENTUALLY THE NORTHERN  
PORTION OF THE COUNTY. THE BAND SHOULD STILL BE PRETTY WEAK DURING  
THE EVENING, BUT MAY STRENGTHEN SOME OVERNIGHT AS THE BOUNDARY LAYER  
FLOW BACKS AND IMPROVES FETCH, AND ALSO AS CONVERGENCE FORCED BY A  
LAND BREEZE CIRCULATION STRENGTHENS. LAKE INDUCED EQUILIBRIUM LEVELS  
WILL BE AROUND 10K FEET, WITH A LITTLE DEEPER LAYER OF DENDRITIC  
CRYSTAL GROWTH AVAILABLE. THIS WILL ALLOW FOR MORE FAVORABLE CLOUD  
MICROPHYSICS FOR LAKE ONTARIO THAN LAKE ERIE. WITH THIS IN MIND,  
THIS BAND OF SNOW MAY PRODUCE 3-6 INCHES OF ACCUMULATION ACROSS  
OSWEGO COUNTY LATER THURSDAY NIGHT AND EARLY FRIDAY MORNING. IN THIS  
CASE WITH AN ANTICYCLONICALLY CURVED BAND ON THE NORTHERN EDGE OF  
HIGH PRESSURE, THE BAND OFTEN DOES NOT EXTEND VERY FAR INLAND, WITH  
THE HEAVIEST SNOW AMOUNTS CLOSE TO THE LAKESHORE. FRIDAY MORNING  
BOUNDARY LAYER FLOW QUICKLY BECOMES SOUTHWEST, WHICH WILL CARRY WHAT  
REMAINS OF THE LAKE EFFECT SNOW INTO NORTHERN JEFFERSON COUNTY. BY  
THIS TIME, ANY ADDITIONAL SNOW AMOUNTS WILL BE LIGHT.  
 
THINGS BECOME MORE INTERESTING AGAIN LATE FRIDAY AFTERNOON AND  
FRIDAY NIGHT, AS ANOTHER CLIPPER PASSES JUST NORTH OF LAKE ONTARIO.  
THE CLIPPER ITSELF WILL BRING SOME LIGHT SNOW TO THE REGION, WITH  
ACCUMULATIONS LESS THAN AN INCH OUTSIDE OF LAKE ENHANCED AREAS. THE  
AIRMASS REMAINS PLENTY COLD ENOUGH FOR LAKE EFFECT SNOW AS THE  
CLIPPER PASSES BY, AND THIS WILL SET THE STAGE FOR SIGNIFICANT LAKE  
ENHANCEMENT. LAKE INDUCED EQUILIBRIUM LEVELS WILL RISE TO ABOUT 15K  
FEET AS THE CLIPPER PASSES BY WITH IMPROVING MOISTURE AND COOLING  
TEMPERATURES ALOFT.  
 
OFF LAKE ERIE, EXPECT A BAND OF LAKE ENHANCED SNOW TO INTENSIFY TO  
THE NORTH OF BUFFALO LATE FRIDAY AFTERNOON AND EARLY EVENING. THIS  
BAND WILL THEN SWEEP RATHER QUICKLY SOUTH ACROSS BUFFALO FRIDAY  
EVENING, ENDING UP IN THE WESTERN SOUTHERN TIER AND WEAKENING LATER  
FRIDAY NIGHT AND EARLY SATURDAY. THE BAND MAY BE QUITE STRONG AS IT  
MOVES SOUTH ACROSS BUFFALO, WITH HIGH SNOWFALL RATES BRIEFLY. THIS  
EVENT MAY EVENTUALLY NEED HEADLINES, BUT THE RELATIVELY FAST BAND  
MOTION MAY KEEP ACCUMULATIONS IN THE ADVISORY RANGE.  
 
OFF LAKE ONTARIO, EXPECT A BAND OF LAKE ENHANCED SNOW OVER NORTHERN  
JEFFERSON COUNTY FRIDAY EVENING TO MOVE SOUTH INTO THE TUG HILL  
REGION OVERNIGHT. SIMILAR TO LAKE ERIE, THIS BAND MAY BECOME QUITE  
STRONG AS IT MOVES SOUTH WITH AN ADDED BOOST OF CONVERGENCE FROM THE  
COLD FRONT ASSOCIATED WITH THE CLIPPER, AND UPSLOPE FLOW INTO THE  
TUG HILL. LATEST NAM/GFS GUIDANCE SUGGESTS THE BAND MAY HOLD OVER  
THE TUG HILL A LITTLE LONGER, WHICH MAY BRING HIGHER SNOWFALL  
TOTALS. EVENTUALLY BOUNDARY LAYER FLOW WILL BECOME NORTHWEST  
SATURDAY MORNING, WITH WEAKENING LAKE EFFECT SNOW SOUTHEAST OF THE  
LAKE. THIS BAND SHOULD PRODUCE AT LEAST ADVISORY AMOUNTS, WITH AT  
LEAST SOME CHANCE OF WARNING CRITERIA SNOW ON THE TUG HILL PLATEAU  
IF THE BAND DOES IN FACT HOLD THERE LONGER. NOT ENOUGH CONFIDENCE IN  
THIS SCENARIO FOR A WATCH YET, BUT WILL CONTINUE TO MONITOR.  
 
ON SATURDAY LAKE EFFECT SNOW SOUTHEAST OF THE LAKES WILL QUICKLY  
DIMINISH AS HIGH PRESSURE BUILDS INTO THE REGION AND THE AIRMASS  
DRIES. THIS SHOULD END ALTOGETHER BY SATURDAY NIGHT AS THE RIDGE  
BUILDS ACROSS THE LAKES.  
 

 
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/
 
 
WITH DOWNSTREAM BLOCKING FINALLY RELAXING A BIT, THE PERSISTENT COLD  
AIR THAT WE'VE BEEN EXPERIENCING IS EXPECTED TO LESSEN A BIT FOR THE  
START OF NEXT WEEK. THIS WILL ALLOW FOR TEMPERATURES TO BEGIN  
MODERATING, WITH DAYTIME HIGHS RETURNING TO THE MID TO UPPER 30S.  
PERHAPS A FEW READINGS NEAR 40 ARE POSSIBLE MONDAY INTO TUESDAY. THE  
PATTERN HOWEVER REMAINS FAIRLY ACTIVE; SHORTWAVES WILL PROVIDE A FEW  
CHANCES FOR SNOW SHOWERS, AND POSSIBLY SOME MIXED PRECIPITATION. THE  
NEXT COOL DOWN AND CHANCE FOR SOME LAKE EFFECT SNOW SHOWERS COMES  
WEDNESDAY INTO THURSDAY AS RIDGING OVER THE PLAINS OPENS THE DOOR  
FOR A NORTHWESTERLY FLOW OF ARCTIC SOURCED AIR ACROSS THE LOWER  
GREAT LAKES.  
 

 
   
AVIATION /06Z THURSDAY THROUGH MONDAY/
 
 
LOW PRESSURE PASSING ACROSS PENNSYLVANIA OVERNIGHT WILL GENERATE  
LIGHT SNOW ACROSS ALL OF WESTERN NEW YORK OVERNIGHT. THIS WILL  
RESULT IN GENERALLY MVFR CIGS WITH IFR TO LIFR VSBYS IN SNOW...WHILE  
VFR CONDITIONS WILL REMAIN IN PLACE OVERNIGHT FOR KART AND KGTB.  
 
AS THE LOW PRESSURE MOVES AWAY FROM THE REGION TODAY...MOST AREAS  
WILL IMPROVE TO VFR CONDITIONS. THE EXCEPTION WILL BE SOUTHEAST OF  
BOTH LAKES...INCLUDING AT KJHW WHERE LAKE EFFECT SNOW SHOWERS WILL  
KEEP AT LEAST MVFR CONDITIONS IN PLACE.  
 
OUTLOOK...  
 
FRIDAY THROUGH SATURDAY...MAINLY VFR EXCEPT LAKE EFFECT SNOW SHOWERS  
WILL BRIEFLY IMPACT TERMINAL LOCATIONS WITH IFR OR LOWER CONDITIONS  
POSSIBLE.  
 
SATURDAY NIGHT THROUGH MONDAY...MAINLY VFR. A CHANCE OF SNOW SHOWERS  
MONDAY.  
 

 
   
MARINE
 
 
A CLIPPER LOW WHICH WILL CAUSE WINDS TO INCREASE OVERNIGHT. THIS  
WILL RESULT IN AN EXTENDED PERIOD OF CONDITIONS WILL GENERALLY FALL  
INTO THE LOWER END OF SMALL CRAFT ADVISORY CRITERIA. WINDS AND WAVES  
MAY BRIEFLY DROP OFF EARLY FRIDAY BUT WINDS WILL INCREASE WITH  
ANOTHER SYSTEM LATE FRIDAY INTO SATURDAY WITH MORE SMALL CRAFT  
HEADLINES LIKELY.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR  
NYZ019>021.  
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR LEZ040-  
041.  
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR  
LOZ043>045.  
SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR LOZ042.  
 

 
 

 
 
SYNOPSIS...APFFEL  
NEAR TERM...HSK/RSH  
SHORT TERM...HITCHCOCK  
LONG TERM...CHURCH/TMA  
AVIATION...RSH  
MARINE...APFFEL/RSH  
 
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