954  
FXUS61 KBUF 230537  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
137 AM EDT TUE OCT 23 2018  
   
SYNOPSIS
 
 
A FEW ADDITIONAL LAKE EFFECT SHOWERS ARE EXPECTED THIS EVENING EAST  
AND NORTHEAST OF LAKE ONTARIO. ON TUESDAY, A COLD FRONT WILL CROSS  
THE REGION ALONG WITH ANOTHER ROUND OF SHOWERS AND POSSIBLE  
THUNDERSTORMS. THIS WILL BE FOLLOWED BY YET ANOTHER BOUT OF LAKE  
EFFECT RAIN AND SNOW SHOWERS INTO THE MIDDLE OF THE WEEK. HIGH  
PRESSURE SHOULD BRING DRY WEATHER THURSDAY AND FRIDAY.  
 

 
   
NEAR TERM /THROUGH TODAY/
 
 
A WEAK PRESSURE GRADIENT IS ACROSS WESTERN AND NORTH CENTRAL NY  
LATE TONIGHT. LIGHT WINDS WILL CONTINUE INTO THE MORNING AHEAD  
OF AN ADVANCING COLD FRONT THAT IS STRETCHED ACROSS MICHIGAN.  
SOME CLEARING HAS OCCURRED NORTHEAST OF THE LAKES WITH WARM AIR  
ADVECTION KEEPING MOISTURE ACROSS INLAND AREAS. CLOUDS WILL FILL  
IN ACROSS THE FORECAST AREA BY MORNING AS THE COLD FRONT NEARS  
WESTERN NY. TEMPERATURES LATE THIS EVENING VARY FROM AROUND 40  
CLOSER TO THE LAKE SHORES TO THE UPPER 30S OVER HIGHER TERRAIN.  
 
TONIGHT LOOKS MAINLY DRY ACROSS MOST OF THE AREA, THE EXCEPTION  
BEING NORTHEAST OF LAKE ONTARIO WHERE SOME CHANCE POPS WILL EXIST AS  
SYNOPTIC MOISTURE WILL BE PLENTIFUL ENOUGH TO SUPPORT THE CHANCE FOR  
SHOWERS. OFF LAKE ERIE TONIGHT THERE WILL BE LESS SYNOPTIC MOISTURE  
TO WORK WITH AND THEREFOR POPS HAVE BEEN LOWERED SINCE EARLIER MODEL  
RUNS. EQUILIBRIUM LEVELS OF AROUND 10KFT OFF OF BOTH LAKES WILL HELP  
TO SUPPORT SOME LAKE EFFECT CLOUDS OVERNIGHT IN AREAS OUTSIDE OF  
LAKE EFFECT PRECIP. LOW TEMPERATURES TONIGHT WILL BE IN THE MID TO  
UPPER 30 ACROSS THE HIGHER TERRAIN AND IN THE LOW 40S FOR AREAS  
CLOSER TO THE LAKES.  
 
A POSITIVELY TILTED UPPER AND MID LEVEL TROUGH OVER CENTRAL ONTARIO  
TONIGHT WILL TREK SOUTHEAST TOWARD THE AREA TUESDAY AFTERNOON WHEN  
THE TROUGH AXIS WILL BE OVER CENTRAL NY. AS THIS TROUGH DIVES  
SOUTHEAST A 500H VORTICITY MAXIMA WILL ENTER THE BASE OF THE TROUGH  
CAUSING THE TROUGH TO BECOME MORE AMPLIFIED AND LESS POSITIVELY  
TILTED AS A RESULT. AT THE SAME TIME, A WEAK SURFACE LOW WILL ALSO  
MOVE SOUTHEAST TOWARD THE AREA OVERNIGHT TONIGHT. THE MAIN AREA OF  
LOW PRESSURE ASSOCIATED WITH THE BEST VORTICITY WILL BE PLACED  
NEAR THE WESTERN END OF LAKE ONTARIO BY AROUND 12Z.  
 
ON TUESDAY, AS THE LOW PRESSURE MOVES ACROSS THE AREA IT WILL TREK  
ALONG LAKE ONTARIO AND CONTINUE SOUTHEAST TO SOUTHERN NEW ENGLAND BY  
LATE TUESDAY. ALONG WITH THIS AREA OF LOW PRESSURE WILL BE A COLD  
FRONT THAT WILL MOVE THROUGH STARTING AROUND 12Z IN WNY AND CLEAR  
THROUGH BY AROUND 20Z TO THE EAST. WITH STEEPENING LAPS RATES AS  
COOLING ALOFT OCCURS GRAUPEL AND THUNDER WILL BE POSSIBLE ALONG AND  
BEHIND THE COLD FRONTAL PASSAGE. MOST OF THE AREA WILL HAVE LIKELY  
POPS WITH THE COLD FRONTAL PASSAGE EXCEPT FOR THE NORTH COUNTRY,  
WHERE THE CENTER OF THE LOW WILL PASS OVER AND JUST SOUTH OF SO  
JUST CHANCE POPS DURING LOW PRESSURE PASSAGE.  
 
BEHIND THE COLD FRONTAL PASSAGE ON TUESDAY THERE WILL BE WIDESPREAD  
CHANCE POPS WITH SYNOPTIC MOISTURE STILL PRESENT AND THE UPPER LEVEL  
TROUGH AND 500H VORT MAX OVER THE AREA. WITH A NORTHWEST FLOW BEHIND  
THIS SYSTEM, THERE WILL BE LAKE EFFECT/ENHANCED RAIN SHOWERS THROUGH  
THE REST OF THE DAY. LAKE EFFECT PRECIP WILL BE MOST PERSISTENT  
SOUTHEAST OF THE LAKES, ESPECIALLY OFF LAKE ONTARIO WHERE BOTH THE  
BEST SYNOPTIC MOISTURE AND BEST FETCH WILL BE IN PLACE.  
 
WATERSPOUTS ALSO CAN'T BE RULED OUT ALONG AND BEHIND THE COLD FRONT  
ON BOTH LAKES, AND ON LAKE ONTARIO LATER IN THE DAY. BEHIND THIS  
COLD FRONT THERE WILL BE COLD AIR ADVECTION WITH THE 850TS DROPPING  
FROM AROUND 0C AHEAD OF THE COLD FRONT TO AROUND -5C BY 00Z TUESDAY  
NIGHT. WITH THESE COOLING TEMPERATURES AND THE LAKES STILL AROUND  
14C, EQUILIBRIUM HEIGHTS OVER/NEAR BOTH LAKES WILL REACH AROUND  
20KFT, COMBINED WITH LCLS OF AROUND 2KFT THERE WILL BE THE INCREASED  
CHANCE FOR WATERSPOUTS.  
 
ON TUESDAY TEMPERATURES WILL WARM THROUGH THE EARLY AFTERNOON BEFORE  
STRONGER COLD AIR ADVECTION OCCURS AND BETTER MIXING HELPS TO HALT  
ANY WARMING. HIGH TEMPERATURES FOR TUESDAY WILL REACH THE UPPER 40S  
ACROSS WNY, NEAR 50 ALONG THE GENESEE VALLEY AND THE LOW 50S FOR THE  
NORTH COUNTRY.  
 

 
   
SHORT TERM /TONIGHT THROUGH FRIDAY/
 
 
TUESDAY NIGHT AN UPPER LEVEL TROUGH WILL DIG ACROSS QUEBEC INTO  
NORTHERN NEW ENGLAND, CLOSING OFF INTO A CLOSED UPPER LEVEL LOW AS  
IT DOES SO. AT THE SURFACE, AN INITIAL WEAK SURFACE LOW OVER  
SOUTHERN ONTARIO AND QUEBEC WILL YIELD TO SECONDARY COASTAL  
CYCLOGENESIS NEAR THE DOWNEAST MAINE COAST. LARGE SCALE ASCENT AND  
DEEPER MOISTURE ASSOCIATED WITH THE MID LEVEL TROUGH WILL CONTINUE  
TO PRODUCE SHOWERS THROUGH THE EVENING FROM THE GENESEE VALLEY  
EASTWARD. BOTH THE GFS/NAM SUGGEST AN AXIS OF DEFORMATION ALONG WITH  
SOME LAKE ENHANCEMENT BRINGING SOMEWHAT HIGHER RAIN AMOUNTS TO  
WAYNE/CAYUGA/OSWEGO COUNTIES THROUGH THE EVENING HOURS.  
 
LATE TUESDAY NIGHT AND WEDNESDAY THE SYNOPTIC SCALE FORCING WILL  
SLOWLY DIMINISH FROM WEST TO EAST AND GIVE WAY TO MORE IN THE WAY OF  
NORTHWEST LAKE RESPONSE AND UPSLOPE FLOW. THE SYNOPTIC SCALE  
MOISTURE DEPTH WILL BE SOMEWHAT LACKING DURING THIS PERIOD, AND THE  
MORE FAVORABLE TEMPERATURE RANGE FOR BERGERON-FINDEISEN CLOUD  
MICROPHYSICS WILL REMAIN DISPLACED LARGELY ABOVE THE TOP OF THE LAKE  
INDUCED EQUILIBRIUM LEVEL. THIS, COMBINED WITH SHORT NORTHWEST FETCH  
WILL LIMIT THE INTENSITY OF THE LAKE AND UPSLOPE RESPONSE.  
 
EXPECT SOME LIMITED LAKE EFFECT SHOWERS TO EXPAND ALONG MUCH OF THE  
SOUTH SHORE OF LAKE ONTARIO LATE TUESDAY NIGHT INTO WEDNESDAY  
MORNING, BEFORE SLOWLY CONTRACTING BACK TO MAINLY AREAS SOUTHEAST OF  
THE LAKE FROM ROCHESTER TO OSWEGO COUNTY AND EXTENDING INTO THE  
FINGER LAKES BY WEDNESDAY AFTERNOON. UPSLOPE WITH LAKE ENHANCEMENT  
WILL ALSO DEVELOP ACROSS THE WESTERN SOUTHERN TIER TUESDAY NIGHT  
THROUGH WEDNESDAY, WITH SOME POSSIBLE UPSTREAM CONNECTION TO LAKE  
HURON AT TIMES OVER CHAUTAUQUA COUNTY. ALL OF THIS WILL REMAIN  
FAIRLY LIGHT IN NATURE. PRECIP TYPE WILL BE ALL RAIN THROUGH TUESDAY  
EVENING. ONGOING COLD ADVECTION WILL COOL THE BOUNDARY LAYER ENOUGH  
TO ALLOW FOR A MIX WITH, AND CHANGE TO WET SNOW ACROSS HIGHER  
TERRAIN LATER TUESDAY NIGHT. SOME WET SNOW MAY ALSO MIX IN DOWN TO  
THE LAKE PLAINS BY WEDNESDAY MORNING. A MIX OF RAIN AND WET SNOW  
WILL THEN CONTINUE THROUGH WEDNESDAY, WITH RAIN FAVORED AT LOWER  
ELEVATIONS AND WET SNOW AT HIGHER TERRAIN BY AFTERNOON.  
ACCUMULATIONS WILL BE MINIMAL, WITH A VERY LIGHT COATING POSSIBLE  
ACROSS HIGHER TERRAIN LATE TUESDAY NIGHT AND WEDNESDAY MORNING,  
NOTHING CLOSER TO THE LAKES.  
 
LOW TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE UPPER 30S NEAR  
THE LAKES TO THE LOWER 30S ACROSS HIGHER TERRAIN. HIGHS WEDNESDAY  
WILL BE IN THE LOW TO MID 40S ON THE LAKE PLAINS AND UPPER 30S  
ACROSS HIGHER TERRAIN.  
 
WEDNESDAY NIGHT LAKE INDUCED EQUILIBRIUM LEVELS FALL STEADILY AS THE  
POOL OF COLDEST AIR ALOFT MOVES OFF, AND HIGH PRESSURE BUILDS INTO  
THE CENTRAL GREAT LAKES. NORTHWEST FLOW BENEATH THE DROPPING  
INVERSION WILL STILL MAINTAIN A CHANCE OF A FEW LAKE EFFECT  
RAIN/SNOW SHOWERS SOUTHEAST OF THE LAKES, BUT THIS ACTIVITY WILL  
REMAIN VERY LIGHT AND SPOTTY. THERE WILL BE PLENTY OF SHALLOW LOW  
LEVEL MOISTURE TRAPPED BENEATH THE FALLING INVERSION, SO EXPECT  
PLENTY OF CLOUDS TO REMAIN IN PLACE. LOWS WILL BE IN THE LOWER 30S  
ON THE LAKE PLAINS, AND MID TO UPPER 20S ACROSS THE SOUTHERN TIER  
AND EAST OF LAKE ONTARIO.  
 
THURSDAY A FEW LAKE EFFECT FLURRIES MAY CONTINUE EARLY IN THE DAY  
SOUTHEAST OF LAKE ONTARIO. OTHERWISE THE LOWERING INVERSION HEIGHTS  
WILL BRING AN END TO ANY LAKE RESPONSE. NORTHWEST UPSLOPE FLOW AND  
SHALLOW LOW LEVEL MOISTURE TRAPPED BENEATH THE INVERSION WILL STILL  
KEEP A GOOD DEAL OF CLOUD COVER AROUND THROUGH AT LEAST THE MORNING  
BEFORE A BETTER CHANCE AT STUBBORN CLEARING DURING THE AFTERNOON.  
TEMPERATURES WILL REMAIN CHILLY, WITH LOWER 40S AT LOWER ELEVATIONS  
AND MID 30S ACROSS HIGHER TERRAIN.  
 
HIGH PRESSURE WILL BUILD EAST ACROSS THE AREA THURSDAY NIGHT AND  
LIKELY BRING THE COLDEST NIGHT YET OF THIS FALL SEASON. EXPECT LOWS  
TO DROP INTO THE 20S AREAWIDE WITH THE POSSIBLE EXCEPTION OF THE  
IMMEDIATE LAKESHORES. HIGH PRESSURE WILL DRIFT TO THE EAST COAST  
FRIDAY. MID LEVEL WARM ADVECTION WILL SPREAD EAST ACROSS THE GREAT  
LAKES IN THE WAKE OF THE DEPARTING HIGH, FORCING HIGH/MID LEVEL  
CLOUDS TO INCREASE FROM WEST TO EAST. HIGHS WILL BE IN THE MID 40S  
FOR MOST, WITH SOME 30S STILL ACROSS THE HIGHER TERRAIN EAST OF LAKE  
ONTARIO.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
 
 
THE FORECAST FOR THIS COMING WEEKEND REMAINS VERY INTERESTING AS IT  
IS HINGED UPON THE EVOLUTION OF THE REMNANTS OF THE PRESET MAJOR  
HURRICANE WILLA IN THE EASTERN PACIFIC OCEAN BASIN. AFTER LANDFALL  
ON THE PACIFIC COAST OF MEXICO LATER TUESDAY, THE LATEST MODEL  
CONSENSUS FROM 22/12Z TRACKS THE REMNANTS EAST ACROSS MEXICO AND THE  
GULF COAST MID TO LATE WEEK. THE REMNANTS ARE THEN FORECAST TO  
TRANSFER TO THE CAROLINA COAST FRIDAY OR FRIDAY NIGHT BEFORE LIFTING  
NORTH THE ALONG THE EAST COAST AS A DEEPENING EXTRATROPICAL CYCLONE  
SATURDAY AND SUNDAY. THIS SYSTEM HAS THE POTENIAL TO DRAW ATLANTIC  
MOISTURE WESTWARD WITH CHANCES OF RAIN AND SNOW POSSIBLE ACROSS  
WESTERN AND NORTH-CENTRAL NEW YORK ARRIVING AS EARLY AS EARLY  
SATURDAY MORNING THEN REMAINING IN THE FORECAST THROUGH THE WEEKEND  
INTO MONDAY. THE 12Z ECWMF AND GEM ARE IN DECENT AGREEMENT WITH THE  
ARRIVAL OF MOISTURE ACROSS NEW YORK THROUGH SATURDAY WHILE THE GFS  
CONTINUES TO KEEP THE SYSTEM TO OUR EAST WITH A POTENTIAL FOR LITTLE  
TO NO PRECIPITATION ACROSS OUR FORECAST AREA. AS THE COASTAL  
STORM/NOR'EASTER EXITS ACROSS THE CANADIAN MARITIMES SUNDAY, THE  
CORE OF THE PARENT MID-LEVEL TROUGH IS FORECAST TO PIVOT ACROSS THE  
GREAT LAKES BRINGING ADDITIONAL CHANCES FOR PRECIPITATION INTO  
MONDAY.  
 
TEMPS ARE FORECAST TO RUN 5-10 DEGREES BELOW NORMAL ACROSS WESTERN  
AND NORTH-CENTRAL NEW YORK SATURDAY THROUGH MONDAY AS THE AMPLIFIED  
MID-LEVEL TROUGH CIRCULATES COOL CANADIAN AIR SOUTH ACROSS THE GREAT  
LAKES. TEMPS WILL LIKELY RANGE FROM THE 40S DURING THE DAYTIME TO  
30S OVERNIGHT. THE COOLER OVERNIGHT TEMPS WILL BRING A RISK FOR RAIN  
TO MIX WITH OR CHANGE OVER TO WET SNOW ESPECIALLY ACROSS THE HIGHER  
TERRAIN. THOSE WITH OUTDOOR PLANS THIS COMING WEEKEND SHOULD  
CONTINUE TO MONITOR FORECAST UPDATES.  
 

 
   
AVIATION /05Z TUESDAY THROUGH SATURDAY/
 
 
SCATTERED LAKE EFFECT SHOWERS WILL BE POSSIBLE ENE OF LAKE ONTARIO  
THROUGH THE OVERNIGHT HOURS, BUT WITH GENERALLY VFR CONDITIONS. A  
COLD FRONT WILL CROSS THE REGION ON TUESDAY WITH A LINE OF SHOWERS  
AND POSSIBLE THUNDERSTORMS, AND ASSOCIATED MVFR CONDITIONS. THE  
EASTERN LAKE ONTARIO REGION MAY BE SPARED FROM THIS LINE. LAKE  
EFFECT SHOWERS WILL GRADUALLY DEVELOP ON NW FLOW TUESDAY AFTERNOON  
WITH INCREASING MVFR AND SOME IFR CIGS AFTER 18Z. TUESDAY NIGHT WILL  
HAVE LAKE EFFECT RAIN/SNOW SHOWERS SOUTHEAST OF BOTH LAKES WITH  
MVFR/IFR.  
 
OUTLOOK...  
 
WEDNESDAY...LAKE EFFECT -SHRASN SE OF THE LAKES WITH VFR/MVFR.  
THURSDAY AND FRIDAY...VFR.  
SATURDAY...VFR...POSSIBLY MVFR WITH SHOWERS.  
 

 
   
MARINE
 
 
A WEAK PRESSURE GRADIENT IS PRESENT ACROSS THE LAKES LATE  
TONIGHT AND WINDS AND WAVES ARE BELOW SMALL CRAFT ADVISORY  
CONDITIONS. A COLD FRONT WILL MOVE ACROSS THE LAKES TUESDAY AND  
WINDS AND WAVES WILL INCREASE BY MID-MORNING. SW FLOW WILL BE  
COME WESTERLY, THEN NORTHWESTERLY INCREASING BEHIND THE FRONT.  
SCA CONDITIONS WILL LIKELY LAST THROUGH WEDNESDAY BEFORE HIGH  
PRESSURE BRINGS LIGHTER WINDS FOR THURSDAY AND FRIDAY. SMALL  
CRAFT ADVISORIES ARE IN EFFECT ALONG LAKE ERIE AND THE SOUTHERN  
SHORE OF LAKE ONTARIO.  
 
THERE WILL BE A CHANCE OF WATERSPOUTS TUESDAY THROUGH WEDNESDAY  
AS LAKE INDUCED EQUILIBRIUM LEVELS RISE TO GREATER THAN 15K  
FEET AS THE NEXT POOL OF COLD AIR ALOFT CROSSES THE EASTERN  
GREAT LAKES.  
 

 
   
BUF WATCHES/WARNINGS/ADVISORIES
 
 
NY...NONE.  
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 4 PM EDT  
WEDNESDAY FOR LEZ040-041.  
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 PM  
EDT THURSDAY FOR LOZ042-043.  
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 2 PM EDT  
THURSDAY FOR LOZ044.  
 

 
 

 
 
SYNOPSIS...SW/ZAFF  
NEAR TERM...HSK/SW  
SHORT TERM...HITCHCOCK  
LONG TERM...SMITH  
AVIATION...SW/ZAFF  
MARINE...HSK/ZAFF  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab NY Page Main Text Page