620
FXUS61 KBUF 180243
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1043 PM EDT SAT APR 17 2021
SYNOPSIS
WEAK HIGH PRESSURE WILL BRING MAINLY DRY WEATHER THROUGH MONDAY,
ALTHOUGH A FEW PASSING WEAK DISTURBANCES ALOFT MAY PRODUCE A FEW
LIGHT, ISOLATED SHOWERS AT TIMES. TEMPERATURES WILL CONTINUE TO
SLOWLY WARM EACH DAY THROUGH MONDAY. UNSETTLED WEATHER WILL THEN
RETURN BY MIDWEEK AS A COLD FRONT AND LOW PRESSURE CROSS THE REGION.
UNSEASONABLY COLD AIR WILL MOVE BACK INTO OUR AREA BY LATE NEXT
WEEK BEHIND THIS SYSTEM.
NEAR TERM /THROUGH SUNDAY/
RADAR SHOWS TWO SMALL AREAS OF ISOLATED SHOWERS, ONE DROPPING ACROSS
LAKE ERIE TOWARD STURGEON POINT AND LAKE ERIE BEACH AND THE
OTHER SLIDING SSE ACROSS EASTERN LAKE ONTARIO. WEAK SHORTWAVE
OVER THE AREA WILL CONTINUE TO RESULT IN THESE SPARSE COVERAGE
ISOLATED SHOWERS REST OF TONIGHT, WITH BEST CHANCE CLOSER TO A
SLIGHTLY BETTER POCKET OF DEEPER MOISTURE ACROSS EASTERN LAKE
ONTARIO REGION. MOST AREAS WILL STAY DRY. TEMPS DROPPED QUICKLY
EAST OF LAKE ONTARIO WITH SOME PARTIAL CLEARING THERE THIS
EVENING. CLOUDS ARE BACK ON THE INCREASE THOUGH SO TEMPS WILL
LIKELY RISE BACK UP A FEW DEGREES REST OF TONIGHT. OVERALL
THOUGH SKIES MORE CLOUDY THAN NOT WILL WITH THE SHORTWAVE OVER
THE AREA WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH, WITH
LOWS IN THE MID TO UPPER 30S IN MOST LOCATIONS.
SUNDAY THE SLOW MOVING SHORTWAVE WILL EXIT THE EASTERN LAKE ONTARIO
REGION BY MIDDAY, WITH ANY SCATTERED SHOWERS TAPERING OFF. A MID
LEVEL RIDGE AND WEAK SURFACE HIGH WILL THEN BUILD INTO THE EASTERN
LAKE ONTARIO REGION. THIS WILL BRING DRY WEATHER IN MOST LOCATIONS.
DIURNAL HEATING AND RELATIVELY COOL TEMPERATURES ALOFT WILL STEEPEN
LAPSE RATES IN THE AFTERNOON, AND MAY PRODUCE A FEW SCATTERED
SHOWERS FORMING PREFERENTIALLY NEAR TERRAIN AND LAKE BREEZE
BOUNDARIES ACROSS NEARBY SOUTHERN ONTARIO, PENNSYLVANIA, THE SAINT
LAWRENCE VALLEY, AND EASTERN NY. SUBSIDENCE BENEATH THE MID LEVEL
RIDGE AND EXPANDING STABLE LAKE SHADOWS SHOULD GENERALLY KEEP THESE
SHOWERS AWAY FROM OUR AREA. TEMPERATURES WILL CONTINUE THEIR SLOW
RECOVERY, WITH HIGHS IN THE MID TO UPPER 50S IN MOST AREAS, COOLER
ALONG THE LAKE ERIE AND LAKE ONTARIO SHORE.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
ANY DIURNALLY DRIVEN SHOWERS ON SUNDAY WILL FIZZLE OUT AFTER SUNSET
MOVING INTO SUNDAY NIGHT. ANOTHER WEAK SHORTWAVE WILL APPROACH FROM
THE WEST AND CROSS SOUTH OF THE AREA MONDAY NIGHT. THIS WAVE SHOULD
REMAIN FAR ENOUGH SOUTH THAT ANY DEVELOPING OVERNIGHT SHOWERS
ASSOCIATED WITH THIS FEATURE SHOULD REMAIN SOUTH OF THE NY/PA
BORDER, BUT A QUICK CLIPPING INTO SOUTHERN CATTARAUGUS AND ALLEGANY
COUNTIES CAN'T BE ENTIRELY RULED OUT. LOWS SUNDAY NIGHT WILL BE IN
THE MID 30S TO LOW 40S.
THE SHORTWAVE LIFTS TO THE NORTHEAST MONDAY WITH ANY SPOTTY
DIURNALLY DRIVEN SHOWERS TIED TO THIS FEATURE. A MOSTLY DRY DAY IS
EXPECTED AS SHOWER ACTIVITY SHOULD REMAIN MAINLY TO THE EAST OF THE
AREA. MONDAY LIKELY TO BE THE WARMEST DAY OF THE WEEK WITH THE
MAJORITY OF THE AREA SEEING HIGHS IN THE UPPER 50S TO MID 60S. WARM
AIR ADVECTION AHEAD OF THE NEXT SYSTEM WILL HELP MODERATE OVERNIGHT
TEMPERATURES AS WELL, ESPECIALLY FOR THE HIGHER TERRAIN LOCATIONS.
LOWS WILL BE IN THE LOW 40S, WITH UPPER 30S ALONG THE NIAGARA
FRONTIER AND ON THE TUG HILL.
ATTENTION THEN TURNS TO AN UPPER LEVEL CLOSED LOW OVER SOUTHERN
ONTARIO PROVINCE. A MORE POTENT SHORTWAVE WILL ROUND THE BASE OF THE
ASSOCIATED TROUGH, BRINGING A COLD FRONT TO THE AREA LATE MONDAY
NIGHT, SLOWLY INCREASING RAIN CHANCES FOR WESTERN NY MOVING INTO
TUESDAY MORNING. HOWEVER, THE FRONT WILL STALL OUT AS IT RUNS UP
AGAINST A WEAKLY AMPLIFYING OFFSHORE RIDGE, SERVING TO BREAK UP THE
LINE OF SHOWERS ASSOCIATED WITH THE FRONT AND SETTING UP A
SOUTHWEST/NORTHEAST ORIENTED BAROCLINIC ZONE OVER THE REGION
TUESDAY. THIS WILL COMPLICATE TUESDAY'S TEMPERATURE FORECAST SOME,
AS THE POSITION OF THIS BOUNDARY WILL INFLUENCE HOW MUCH DIURNAL
HEATING IS OFFSET BY INCREASED CLOUD COVER AND THE COOLER AIR
FILTERING IN BEHIND THE BOUNDARY ON A MORE NORTHWESTERLY FLOW. AS OF
NOW, CURRENTLY EXPECTING HIGH TEMPERATURES RANGING FROM THE LOW 50S
NEAR THE LAKES TO THE LOW 60S FURTHER INLAND CLOSER TO THE FINGER
LAKES REGION.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
THE CLOSED LOW OVER THE HUDSON BAY, SPANNING ITS ASSOCIATED TROUGH
SOUTH ACROSS THE MID-WESTERN STATES, WILL ALLOW AN ADDITIONAL POTENT
SHORTWAVE TO PASS THROUGH ITS BASE TUESDAY NIGHT, WHICH WILL HELP
ADVANCE THE TROUGH EAST AND PULL THE CLOSED LOW SOUTH OUT OF THE
HUDSON BAY AND INTO THE NORTHERN GREAT LAKES BY WEDNESDAY NIGHT. THE
CLOSED LOW WILL CONTINUE TO ALLOW A FEW SHORTWAVES TO ROTATE THROUGH
WHILE IT CROSSES OVERHEAD OF NORTHEASTERN NEW YORK THURSDAY BEFORE
HEADING NORTHEAST INTO THE CANADIAN MARITIMES. UPPER LEVEL RIDGING
WILL THEN ENSUE FOR THE END OF THE WEEK.
WHILE THE SHORTWAVE ROUNDS THE BASE OF THE UPPER LEVEL TROUGH ON
TUESDAY, THIS WILL NOT ONLY SLOWLY ADVANCE THE COLD FRONT EASTWARD,
BUT ALSO INDUCE A SURFACE LOW TO FORM OVER MISSOURI/ILLINOIS. THIS
LOW WILL THEN PROGRESS NORTHEAST OVERHEAD OF NY STATE, PUSHING THE
COLD FRONT THROUGH FIRST LATE TUESDAY NIGHT AND WEDNESDAY.
THEREFORE, EXPECT A DRY START TO THE DAY ON TUESDAY WITH CHANCES FOR
SOME RAIN SHOWERS TO INCREASE LATE TUESDAY AFTERNOON THROUGH
WEDNESDAY. A MUCH COLDER AIR MASS WILL WORK ITS WAY ACROSS THE
REGION WEDNESDAY, WITH NEARLY A 15 DEGREE DROP IN TEMPERATURE AT
850MB. HIGH TEMPERATURES WEDNESDAY WILL LIKELY OCCUR EARLY IN THE
DAY BEFORE THE FRONTAL PASSAGE, WITH HIGHS IN THE UPPER 40S AND LOW
50S.
AS THE SURFACE LOW DEPARTS NORTHEAST OUT OF THE AREA, ONLY CHANCES
FOR A FEW LAKE ENHANCED SNOW SHOWERS WILL LIE ACROSS THE FAR EASTERN
PORTIONS OF THE AREA WEDNESDAY NIGHT. YET ANOTHER SHORTWAVE WILL
PASS THROUGH THE NOW UPPER LEVEL CLOSED LOW, WHICH WILL INTERACT
WITH THE LEFTOVER WRAP AROUND MOISTURE THURSDAY TO CONTINUE TO
SUPPORT THE LAKE ENHANCED SHOWERS SNOW SHOWERS IN THE EARLY MORNING
BEFORE SWITCHING TO ALL RAIN DUE TO THE ADDITION OF THE SUN FOR
PLACES ACROSS THE FINGER LAKES REGION AND TO ITS EAST. WHILE A MUCH
COLDER AIR MASS OVERHEAD WOULD TYPICALLY SUPPORT COLDER TEMPERATURES
(TO THE TUNE OF NEAR FREEZING), THANKS TO THE HIGHER SUN ANGLE THIS
TIME OF YEAR HIGH TEMPERATURES WILL WARM UP INTO THE 40S.
UPPER LEVEL RIDGING LATE THURSDAY NIGHT THROUGH FRIDAY WILL PROMOTE
MAINLY DRY CONDITIONS. LOOKING INTO THE WEEKEND, A SHORTWAVE
ATTACHED TO THE NEXT INCOMING UPPER LEVEL TROUGH MAY ROLL THROUGH
WHICH WILL SUPPORT A FRONTAL BOUNDARY TO APPROACH THE AREA SATURDAY.
HOWEVER, THIS FAR OUT THE MODEL GUIDANCE IS IN DISAGREEMENT WITH
TIMING OF THE FEATURE AND THEREFORE HAVE LOW CHANCES FOR SHOWERS
SATURDAY. OTHERWISE, UPPER LEVEL RIDGING WILL HELP ADVECT WARM AIR
BACK INTO THE REGION, REBOUNDING TEMPERATURES INTO THE 50S FRIDAY
AND EVEN A FEW LOW 60S SATURDAY.
AVIATION /03Z SUNDAY THROUGH THURSDAY/
WEAK SHORTWAVE WILL CONTINUE TO DRIFT EAST ACROSS THE AREA TONIGHT,
WITH A FEW SHOWERS POSSIBLE THROUGH SUNDAY MORNING, MAINLY EAST OF
LAKE ONTARIO. EVEN SO, MOST AREAS WILL SEE NO RAIN.
AFTER MAINLY VFR CIGS THIS EVENING, MVFR CIGS WILL BECOME MORE
WIDESPREAD AGAIN LATE TONIGHT AND SUNDAY MORNING EAST OF LAKE
ONTARIO, WITH SOME IFR POSSIBLE ACROSS HIGHER TERRAIN. A FEW PATCHES
OF MVFR CIGS AREA ALSO POSSIBLE EAST OF LAKE ERIE LATE TONIGHT AND
SUNDAY MORNING.
WEAK HIGH PRESSURE SURFACE AND ALOFT WILL THEN BRING A RETURN TO
MAINLY VFR BY SUNDAY AFTERNOON WITH DIURNAL CUMULUS DEVELOPING
INLAND FROM THE STABLE LAKE SHADOWS.
OUTLOOK...
MONDAY...MAINLY VFR.
TUESDAY...MVFR TO VFR WITH A CHANCE OF SHOWERS.
TUESDAY NIGHT AND WEDNESDAY...IFR/MVFR WITH RAIN SHOWERS BECOMING
LIKELY.
THURSDAY...MVFR/IFR WITH SCATTERED SNOW SHOWERS AND SOME LAKE EFFECT
SNOW SHOWERS EAST OF THE LAKES. WINDY.
MARINE
SOUTHWEST WINDS OF 10-15 KNOTS ON LAKE ERIE WILL CONTINUE TO PRODUCE
CHOPPY CONDITIONS OVERNIGHT. WEST WINDS WILL THEN INCREASE LATE
TONIGHT AND SUNDAY ON LAKE ONTARIO AS WELL, PRODUCING A ROUND OF
CHOPPY CONDITIONS. IN BOTH CASES THOUGH, WINDS AND WAVES ARE
EXPECTED TO REMAIN A LITTLE BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL THEN DIMINISH SUNDAY NIGHT, WITH GENERALLY LIGHT
SOUTHWEST WINDS ON MONDAY.
BUF WATCHES/WARNINGS/ADVISORIES
NY...NONE.
MARINE...NONE.
SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK/JLA
SHORT TERM...PP
LONG TERM...EAJ
AVIATION...HITCHCOCK/JLA
MARINE...HITCHCOCK/JLA
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