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
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