586
FXUS61 KCLE 010321
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
1021 PM EST SAT NOV 30 2024
SYNOPSIS
A SURFACE TROUGH WILL CONTINUE TO IMPACT THE AREA INTO EARLY NEXT
WEEK. A BRIEF RIDGE TRIES TO BUILD NORTHWARD ACROSS THE OHIO
VALLEY TUESDAY INTO WEDNESDAY. ANOTHER LOW PRESSURE WILL TRACK
EAST ACROSS THE UPPER GREAT LAKES INTO QUEBEC BY THURSDAY,
MOVING A COLD FRONT THROUGH THE AREA WEDNESDAY NIGHT.
NEAR TERM /THROUGH SUNDAY NIGHT/
9:30 PM UPDATE...
THE LAKE-EFFECT SNOW BAND HAS BEGUN ITS SHIFT BACK TO THE SOUTH.
THIS TREND WILL BE MONITORED OVERNIGHT, WITH MODERATE TO HEAVY
SNOW STARTING ALONG THE ERIE, PA LAKESHORE AFTER 06 OR 07Z AND
ALONG THE LAKE AND ASHTABULA COUNTY SHORES BY SUNRISE. CURRENT
SNOW AMOUNTS AND TIMING LOOKS REASONABLE. CLEANED UP THE WORDING
IN THE WINTER WEATHER HEADLINES TO REFLECT THE NEW SNOWFALL AND
IMPACTS ON TOP OF WHAT HAS ALREADY FALLEN. THERE REMAINS SOME
UNCERTAINTY IN CRAWFORD COUNTY, PA WITH HOW FAR SOUTH THE BAND
WILL REACH SUNDAY. IT MAY NOT GET INTO NORTHERN PARTS OF THE
COUNTY UNTIL SUNDAY NIGHT, AND THIS COULD CHANGE SNOWFALL TOTALS
THERE. GIVEN THE UNCERTAINTY, KEPT CRAWFORD IN A WATCH FOR ONE
MORE CYCLE.
WE WANT TO AGAIN EMPHASIZE THAT AREAS ALONG THE LAKESHORE AND
I-90 CORRIDOR FROM ABOUT MADISON AND PERRY, OHIO TO ERIE AND
NORTH EAST, PA HAVE RECEIVED 25 TO 45 INCHES OF SNOW SINCE
THURSDAY NIGHT. RECOVERY OPERATIONS ARE ONGOING IN THESE AREAS,
SO THE ADDITIONAL 12 TO 24+ INCHES EARLY SUNDAY INTO TUESDAY
WILL EXACERBATE THE SITUATION. PLEASE DO NOT VENTURE INTO THESE
AREAS. ROADS ARE LIKELY TO BECOME IMPASSABLE AGAIN, SO
TRAVELING IN THESE AREAS WILL BE EXTREMELY DANGEROUS WITH THE
RISK OF BECOMING STUCK.
6:30 PM UPDATE...
THE OVERALL THINKING OF THE FORECAST HAS NOT CHANGED. THE
PERSISTENT LAKE-EFFECT SNOW BAND IS LIKELY AT ITS MOST OFFSHORE
POSITION OVER THE NEXT 5 HOURS OR SO. THE BAND CURRENTLY
STRETCHES FROM THE NW BASIN OF THE LAKE TO THE BUFFALO SOUTH
TOWNS. THIS BAND SHOULD REMAIN NEARLY STATIONARY THROUGH ABOUT
05Z, OCCASIONALLY CLIPPING NE ERIE COUNTY WITH LIGHT SNOW.
OTHERWISE, JUST FLURRIES WILL CONTINUE OVER EASTERN LAKE,
NORTHERN ASHTABULA, AND NW ERIE COUNTIES. AFTER 05Z, THE BAND
WILL BEGIN TO INCH SLOWLY BACK SOUTHWARD AS THE BOUNDARY LAYER
FLOW VEERS TOWARD 260-270 DEGREES IN RESPONSE TO A WEAK
SHORTWAVE AND ASSOCIATED SURFACE TROUGH CROSSING THE REGION.
THIS WILL START TO BRING THE BAND BACK INTO MORE OF NORTHERN
ERIE COUNTY FIRST, INCLUDING THE CITY OF ERIE, BEFORE AFFECTING
NORTHERN PORTIONS OF ASHTABULA AND LAKE COUNTIES TOWARD
SUNRISE. ONCE THIS BAND REORIENTS WEST-EAST LATE TONIGHT AND
SUNDAY, IT SHOULD BE VERY SLOW TO MOVE VERY FAR INLAND DUE TO
RENEWED STRENGTHENING OF THE THERMAL LAKE AGGREGATE TROUGH NEAR
THE SOUTH SHORE. ADJUSTED POPS THIS EVENING THROUGH SUNDAY NIGHT
TO ACCOUNT FOR THE LATEST PROJECTIONS ON HOW THE BAND MIGHT
MOVE, AND TIMED THE SLOW MOVEMENT BETWEEN THE RGEM AND WRF-ARW
POSITIONING SINCE THEY HAVE THE BEST HANDLE ON THE THERMAL
TROUGHING AND RESULTANT STRONG LOW-LEVEL CONVERGENCE. THIS WILL
UNFORTUNATELY RESULT IN THE POTENTIAL FOR VERY HEAVY SNOWFALL
ONCE AGAIN ALONG THE I-90 CORRIDOR SUNDAY INTO SUNDAY NIGHT, BUT
THIS TIME MORE OF LAKE AND EVENTUALLY NE CUYAHOGA COUNTY WILL
BE AFFECTED AS MEAN LOW-LEVEL FLOW BECOMES AROUND 280 DEGREES BY
SUNDAY EVENING COMBINED WITH THE LOW-LEVEL CONVERGENCE. THIS
WILL ALSO BRING HEAVY SNOW INTO NORTHERN GEAUGA COUNTY BY SUNDAY
EVENING, SO THE CURRENT WARNINGS LOOK REASONABLE FOR SUNDAY AND
SUNDAY NIGHT.
ORIGINAL DISCUSSION...
AFTER A RECORD BREAKING LAKE EFFECT SNOWFALL EVENT FOR ERIE PA
AND PORTIONS OF THE SNOWBELT OF FAR NEOH AND NWPA, WE ARE IN A
LULL THIS AFTERNOON AS THE MAIN SNOW BAND HAS SHIFT OFFSHORE
OVER LAKE ERIE. SOME AREAS HAVE SEEN SOME SUNSHINE THIS
AFTERNOON BUT TEMPERATURES HAVE STAYED BELOW FREEZING ALL DAY.
THE BREAK WITH THE HEAVY SNOWFALL WILL BE SHORT BECAUSE WE ARE
EXPECTING PART 2 OF THIS MULTIDAY LAKE EFFECT SNOW EVENT TO
START UP AGAIN LATER TONIGHT AND CONTINUE FOR A COUPLE MORE
DAYS.
A LARGE CYCLONIC FLOW CONTINUES OVER THE GREAT LAKES REGION
WITH THE CENTER OF THIS SYSTEM SOUTH OF JAMES BAY CANADA THIS
AFTERNOON. THIS AXIS OF THIS MID AND UPPER LEVEL TROUGH WILL
MOVE TOWARDS SOUTHERN AND SOUTHEASTERN QUEBEC BY SUNDAY NIGHT.
THE LOW LEVEL FLOW HAS BRIEFLY BECOME MORE WEST-SOUTHWESTERLY
THIS AFTERNOON WHICH HAS HELPED PUSH THE MAIN LAKE EFFECT SNOW
BAND AND MOST OF THE LAKE EFFECT SNOW SHOWERS JUST OFFSHORE OF
NEOH AND NWPA. THERE IS A SMALLER SECONDARY AND LESS ORGANIZED
LAKE EFFECT SNOW BAND HUGGING THE LAKESHORE AREAS OF LAKE AND
ASHTABULA COUNTIES THIS AFTERNOON. THIS SECONDARY LAKE EFFECT
BAND WILL CONTINUE THROUGH THE EVENING.
THE LOW LEVEL FLOW IS EXPECTED TO BECOME MORE WESTERLY TONIGHT
INTO SUNDAY MORNING AND THE CONVERGENT FOR THE MAIN LES WILL
SLOWLY COME BACK SOUTHWARD CLOSER TO THE LAKESHORE OF NEOH AND
NWPA. ANOTHER TROUGH WILL SWING THROUGH THE EASTERN GREAT LAKES
ON SUNDAY AND THE LOW LEVEL FLOW WILL EVENTUALLY BECOME WEST-
NORTHWESTERLY BY LATE IN THE DAY. WE EXPECTED THE MAIN WEST TO
EAST SNOW BAND WILL BECOME MORE DIFFUSE INTO MULTI BANDS GIVEN
THE MORE NORTHWESTERLY, 270 TO 290 DEGREES FLOW LATE SUNDAY
THROUGH SUNDAY NIGHT. THIS WILL PUT MORE OF PRIMARY SNOWBELT AND
PORTIONS OF THE SECONDARY SNOWBELT INTO THE POTENTIAL FOR LAKE
EFFECT SNOW LATE SUNDAY THROUGH SUNDAY NIGHT.
WE HAVE UPGRADE GEAUGA AND CUYAHOGA COUNTIES TO A LAKE EFFECT
SNOW WARNING STARTING SUNDAY AFTERNOON. FOR CUYAHOGA COUNTY,
THIS LAKE EFFECT SNOW WARNING AND THE HEAVIEST SNOWFALL WILL BE
MAINLY FOR THE EASTERN HALF OF THE COUNTY. FOR THE CLEVELAND
AREA AND EASTWARD, THE POTENTIAL FOR HEAVY LAKE EFFECT SNOW WILL
INCREASE AFTER SUNSET SUNDAY EVENING THROUGH THE NIGHT. WE HAVE
MADE NO CHANGES TO THE WINTER STORM WATCH FOR CRAWFORD COUNTY
PA AT THIS TIME DUE TO SOME UNCERTAINTY. FOR EXPECTED SNOWFALL
TOTALS, AMOUNTS, AND TIMING FOR EACH COUNTY IN THE HEADLINES,
SEE THE WSW TEXT PRODUCT OR THE GRAPHICS ON OUR WEBPAGE.
ELSEWHERE OUTSIDE OF THE IMPACTED SNOWBELT REGION, WE ARE
EXPECTED PARTLY CLOUDY TO MOSTLY CLOUDY SKIES. THERE COULD BE A
PASSING LIGHT SNOW SHOWER OR FLURRIES FROM TIME TO TIME BUT WE
ARE NOT EXPECTING ANY SNOWFALL OR WINTER WEATHER IMPACTS. HIGH
TEMPERATURES WILL BE IN THE UPPER 20S TO LOW 30S SUNDAY.
OVERNIGHT LOW TEMPS WILL IN THE UPPER TEENS AND LOWER 20S.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
ACTIVE WEATHER WILL CONTINUE FOR THE SHORT TERM PERIOD AS LAKE
EFFECT SNOW CONTINUES ACROSS THE SNOWBELT UNDERNEATH PRIMARILY
NORTHWEST FLOW ALOFT. TWO AREAS OF INTEREST IN PARTICULARY COULD
YIELD THE HIGHEST SNOW AMOUNTS - THE FIRST BEING FAR EASTERN
CUYAHOGA, SOUTHERN LAKE, AND NORTHERN GEAUGA COUNTIES, WHERE SURFACE
CONVERGENCE COULD RESULT IN A STRONGER BAND PRODUCING LOCALIZED
HIGHER SNOW AMOUNTS. THIS COULD HAVE SIGNIFICANT IMPACTS ON THE
MONDAY MORNING COMMUTE ACROSS THE AREA. THE SECOND AREA OF CONCERN
IS ACROSS NORTHWEST PENNSYLVANIA WHERE NORTHWEST FLOW OFF OF LAKE
HURON MAY ADD ADDITIONAL LOW-LEVEL MOISTURE, ENHANCING ANY EXISTING
SNOW BANDS. THERE STILL REMAINS SOME DEGREE OF UNCERTAINTY ON THE
INTENSITY AND GENERAL ORGANIZATION OF THE LAKE EFFECT SNOW ON MONDAY
GIVEN INCREASING BOUNDARY LAYER SHEAR AND SHORTER FETCH.
BY MONDAY NIGHT INTO TUESDAY, A RIDGE WILL BEGIN TO BUILD EAST
ACROSS THE MIDWEST, THOUGH CONTINUED WESTERLY FLOW ALOFT AND A
CHILLY AIR MASS OVERHEAD SHOULD MAINTAIN LAKE EFFECT SNOW ACROSS
PORTIONS OF FAR NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA THROUGH
MUCH OF TUESDAY. WE WILL MAINTAIN THE CURRENT HEADLINE END TIME OF 7
AM TUESDAY FOR THIS PACKAGE, THOUGH CAN'T RULE OUT EXTENSIONS INTO
TUESDAY AFTERNOON. LAKE EFFECT SNOW IS EXPECTED TO END LATE TUESDAY
NIGHT AS FLOW ALOFT SHIFTS TOWARDS THE SOUTHWEST AND PUSHES ANY
LINGERING SNOW NORTH ACROSS LAKE ERIE.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
THE ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE LONG TERM PERIOD AS
ANOTHER LOW PRESSURE SYSTEM DIGS SOUTHEAST ACROSS THE GREAT LAKES.
THIS SYSTEM WILL LIKELY BRING A BRIEF PERIOD OF WIDESPREAD LIGHT
SNOW ACROSS THE REGION LATE WEDNESDAY INTO THURSDAY. THIS SYSTEM
WILL BRING ANOTHER COLD AIR MASS SOUTHWARD ACROSS THE REGION TOWARDS
THE END OF THE WEEK AND INTO THE WEEKEND, WITH LOW TO MODERATE
PROBABILITIES (30 TO 50%) THAT 850 MB TEMPERATURES COULD DROP TO
AT LEAST -14C. THIS COLD AIR MASS WILL BE ACCOMPANIED BY
NORTHWEST FLOW WHICH WILL RESULT IN ADDITIONAL LAKE EFFECT SNOW
SHOWERS ACROSS THE SNOWBELT AND PERHAPS HIGHER COVERAGE ACROSS
THE SECONDARY SNOWBELT THIS TIME AROUND.
BELOW AVERAGE TEMPERATURES WILL PERSIST FOR THE LONG TERM PERIOD
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. IN ADDITION, SINGLE DIGIT
WIND CHILLS ARE LIKELY TO RETURN DURING THE OVERNIGHT AND EARLY
MORNING HOURS.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
OUTSIDE OF THE LAKE-EFFECT MESS, TAFS WILL BE VFR THROUGH THE
PERIOD WITH JUST OCCASIONAL FLURRIES AND LIGHT SNOW SHOWERS
SUNDAY AFTERNOON, MAINLY AROUND KMFD AND KYNG AIDED BY SOME
UPSLOPING. SW WINDS WILL DECREASE TO 5-10 KNOTS TONIGHT FOLLOWED
BY AN INCREASE TO 10-20 KNOTS SUNDAY WHILE SLOWLY BECOMING MORE
W TO WSW.
REGARDING THE LAKE-EFFECT AFFECTING KERI, THE BAND WILL STAY
MOSTLY OFFSHORE THROUGH THE FIRST HALF OF TONIGHT, WITH JUST
OCCASIONAL LIGHT SNOW BRUSHING THE TERMINAL. STARTING AFTER
ABOUT 06Z TONIGHT, THE BAND WILL BEGIN TO MOVE BACK ONSHORE AS
THE FLOW TURNS MORE WESTERLY. THIS WILL BRING HEAVY SNOW
GRADUALLY BACK INTO THE KERI TERMINAL. WENT A LITTLE
CONSERVATIVE IN THE TAF WITH MVFR STARTING AROUND 08Z BECOMING
LIFR AFTER 12Z IN MODERATE SNOW, WITH A TEMPO FOR HEAVY SNOW AND
1/4 MILE VISIBILITY THROUGH THE MORNING. HOWEVER, IT'S POSSIBLE
IF NOT LIKELY THAT MOST OF SUNDAY COULD HAVE HEAVY SNOW AND
VISIBILITY BELOW 1/4 MILE, MUCH LIKE WHAT OCCURRED FRIDAY.
CONDITIONS SHOULD GRADUALLY IMPROVE SUNDAY EVENING. AT THIS
TIME, KEPT THE STEADY SNOW NORTH OF KCLE AND KYNG SUNDAY
EVENING, BUT IT WILL GET CLOSE TO KYNG BY THE END OF THE TAF
PERIOD. IT PROBABLY WILL NOT REACH KCLE UNTIL LATER SUNDAY
NIGHT.
OUTLOOK...NON-VFR LIKELY IN PERIODIC LAKE-EFFECT SNOW THROUGH
TUESDAY. THE HEAVIEST AND MOST-PERSISTENT LAKE-EFFECT SNOW IN
OUR REGION IS EXPECTED TO IMPACT THE PRIMARY SNOWBELT IN FAR
NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA.
MARINE
ROUGH MARINE CONDITIONS ARE EXPECTED TO PERSIST THROUGH AT LEAST MID-
NEXT WEEK FOR MUCH OF LAKE ERIE. FLOW WILL PRIMARILY REMAIN WEST TO
NORTHWEST, 15 TO 25 KNOTS, THROUGH TUESDAY, BEFORE BECOMING
SOUTHWEST, 25 TO 30 KNOTS, ON WEDNESDAY. WILL NEED TO MONITOR TRENDS
FOR POTENTIAL GALE CONDITIONS BEHIND A COLD FRONT WEDNESDAY NIGHT
INTO THURSDAY AS WINDS SHIFT TOWARDS THE NORTHWEST, AROUND 30 KNOTS.
THE LOW WATER ADVISORY REMAINS ACROSS THE WESTERN BASIN AS WATER
LEVELS AT TOLEDO HOVER AROUND THE CRITICAL MARK OF 2 INCHES ABOVE
LOW WATER DATUM. HAVE MAINTAINED THE CURRENT END TIME OF 10 PM THIS
EVENING AS WINDS ARE EXPECTED TO SHIFT TOWARDS THE WEST.
CLE WATCHES/WARNINGS/ADVISORIES
OH...LAKE EFFECT SNOW WARNING FROM NOON SUNDAY TO 7 AM EST TUESDAY
FOR OHZ011-013.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR OHZ012-014-
089.
PA...LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR PAZ001-002.
WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH TUESDAY
MORNING FOR PAZ003.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR LEZ145>149.
SYNOPSIS...GRIFFIN
NEAR TERM...GARUCKAS/GRIFFIN
SHORT TERM...KAHN
LONG TERM...KAHN
AVIATION...GARUCKAS
MARINE...KAHN
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