505
FXUS61 KCLE 271450
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
950 AM EST WED NOV 27 2024
SYNOPSIS
LOW PRESSURE TRACKS THROUGH THE OHIO VALLEY LATE THIS EVENING
INTO TONIGHT AND THURSDAY. COLD AIR FLOWS IN BEHIND THIS LOW
PRESSURE BEGINNING THURSDAY NIGHT AND INTO THE WEEKEND WITH LAKE
EFFECT SNOW SETTING UP FOR THE REGION.
NEAR TERM /THROUGH THURSDAY/
9:50 AM EST UPDATE...
FORECAST REMAINS VALID PER LATEST TRENDS IN OBS AND MODEL
GUIDANCE. NO CHANGES APPEARED NECESSARY AT THIS TIME. WILL
CONTINUE TO ASSESS HOW MUCH RAIN VERSUS SNOW WILL OCCUR TONIGHT
INTO THANKSGIVING MORNING IN ASSOCIATION WITH THE NEXT LOW
PRESSURE SYSTEM TO IMPACT OUR AREA. LOW-LEVEL TEMPS/WET-BULB
TEMPS, INCLUDING THOSE AT THE SURFACE, WILL BE CRITICAL FOR HOW
MUCH RAIN VERSUS SNOW OCCURS AND SNOW ACCUMULATION POTENTIAL.
PLEASE SEE DISCUSSION BELOW FOR DETAILS.
PREVIOUS DISCUSSION...
SURFACE LOW GOING TO EJECT OUT OF THE SOUTHERN HIGH PLAINS REGION
INTO THE LOWER MISSISSIPPI VALLEY TODAY, THE OHIO VALLEY LATE THIS
EVENING, AND INTO THE CENTRAL APPALACHIANS TONIGHT. HAVE BEEN
WATCHING THIS TRACK CAREFULLY OVER THE PAST SEVERAL DAYS ALONG WITH
THE NORTHWARD EXTENT OF THE PRECIPITATION SHIELD. BRING IN THE POPS
AROUND 21Z TODAY IN THE SOUTHWESTERN ZONES, SPREADING EASTWARD AND
GRADUALLY NORTHWARD TONIGHT. BEST FORCING IN TERMS OF THE LOW LEVEL
F-GEN WILL BE SOUTH OF THE CWA. TEMPERATURES AT THE SURFACE AND IN
THE COLUMN ARE MARGINAL, SO SNOW RATIOS ARE NOT GOING TO BE ALL THAT
COOPERATIVE IN TERMS OF ACCUMULATING SNOW. HOWEVER, THE MID LEVEL
TROUGH AXIS APPEARS TO DIG SLIGHTLY AS IT COMES THROUGH THE CWA, SO
BRING THE TEMPERATURES AT THE SURFACE CLOSE TO FREEZING FOR THE 06-
15Z TIME FRAME ON THURSDAY. OVERALL, COULD SEE AROUND AN INCH IN
THE HIGHER TERRAIN NEAR MFD AND IN THE EASTERN SECTION OF CRAWFORD
COUNTY PA, AND MAINLY JUST A COATING IN BETWEEN THOSE AREAS AWAY
FROM LAKE ERIE, AND EXCLUDING NW OH/TOL AREA AS WELL. TEMPERATURES
RECOVER FAIRLY QUICKLY INTO THE 40S FOR THURSDAY, SO WILL NOT BE
EXPECTING ANYTHING THAT ACCUMULATES OVERNIGHT TO STICK AROUND.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
THE SHORT TERM FORECAST PERIOD WILL FEATURE THE ORGANIZATION OF A
MULTI-DAY LAKE EFFECT SNOW EVENT TO THE LEE OF LAKE ERIE THAT WILL
HAVE SOME SIGNIFICANT IMPACTS TO POST-HOLIDAY TRAVEL ACROSS
NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. WITH HIGHER CONFIDENCE IN
IMPACTFUL LAKE EFFECT SNOW, A WINTER STORM WATCH HAS BEEN ISSUED FOR
ERIE AND CRAWFORD COUNTIES IN PA AND ASHTABULA AND LAKE COUNTIES IN
OH FROM MIDNIGHT FRIDAY MORNING TO 7 AM ON MONDAY. HOWEVER, THERE
STILL REMAINS SOME UNCERTAINTY IN THE EXACT PLACEMENT AND TIMING OF
LAKE EFFECT SNOW BANDS ACROSS THE REGION AND HOW QUICKLY SNOW WILL
TAPER OFF EARLY NEXT WEEK. ANY HEAVY LAKE EFFECT SNOW BANDS WILL
HAVE THE POTENTIAL FOR 1 TO 2 INCH PER HOUR SNOWFALL RATES AND POOR
VISIBILITY, AS LOW AS ONE QUARTER OF A MILE, WHICH COULD MAKE TRAVEL
DIFFICULT TO IMPOSSIBLE, ESPECIALLY ALONG INTERSTATES 90, 86, AND
79.
WITH A COLD FRONT MOVING THROUGH THE REGION ON THURSDAY NIGHT,
STRONG COLD AIR ADVECTION WILL ENTER WITH 850 MB TEMPERATURES
DROPPING TO -9 TO -11 C AROUND DAY BREAK ON FRIDAY. THE PREVAILING
FLOW ACROSS THE LAKE WILL BE AROUND DUE WEST AND THERE SHOULD BE
PLENTY OF RESIDUAL SYNOPTIC MOISTURE PRESENT ACROSS THE REGION. ALL
OF THESE INGREDIENTS WILL BE IN PLACE TO ALLOW FOR SOME LAKE EFFECT
SNOW TO BEGIN ACROSS THE REGION. MEANWHILE ON FRIDAY MORNING, A
STRONGER WAVE OF ENERGY ALOFT WILL MOVE THROUGH THE REGION AS AN
UPPER LOW SPINS OVER NORTHEAST ONTARIO. THIS WILL ENHANCE THE LIFT
ACROSS THE AREA AND ALLOW FOR MORE EFFICIENT LAKE EFFECT TO DEVELOP
AND SUSPECT THAT THERE WILL BE HEAVY LAKE EFFECT SNOW BANDS
IMPACTING NW PA AND NE OH ON FRIDAY MORNING AND AFTERNOON. THIS WILL
BE A PERIOD TO WATCH FOR SOME OF THE MOST NOTABLE IMPACTS OF THIS
MULTI-DAY LAKE EFFECT SNOW EVENT. FOR SATURDAY, IT APPEARS THAT THE
FLOW WILL BACK JUST A TOUCH BEHIND THE WAVE OF ENERGY ALOFT AND THE
SNOW BANDS MAY LIFT NORTH TO OVER THE LAKE AND FOCUS INTO WESTERN NY
VS. NW PA. IN THE END, THERE IS LOWER CONFIDENCE ON THE SNOW BAND
PLACEMENT ON SATURDAY AND WILL CONTINUE TO HAVE SOME POPS FOR FAR NE
OH AND NW PA. TEMPERATURES WILL BE COLD FOR FRIDAY AND SATURDAY
BEHIND THE FRONT WITH HIGHS TRENDING DOWN WITH 30S ON FRIDAY AND
LIKELY NOT ABOVE FREEZING FOR SATURDAY. OVERNIGHT LOWS WILL BE IN
THE TEENS.
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
THE MAIN WEATHER STORIES FOR THE LONG TERM FORECAST PERIOD WILL BE
CONTINUED LAKE EFFECT SNOW TO THE LEE OF LAKE ERIE AND SUSTAINED
COLD ACROSS THE REGION. WITH FAVORABLE FETCH OVER LAKE ERIE AT
DAYBREAK ON SUNDAY MORNING, 850 MB TEMPERATURES OF -11 TO -13 C
OVERHEAD, AND SUFFICIENT MOISTURE ACROSS THE REGION, THERE SHOULD BE
SOME ONGOING, POTENT LAKE EFFECT SNOW BANDS OCCURRING ACROSS THE
REGION ON SUNDAY. WITH A WESTERLY FETCH, BANDS SHOULD BE INTO ERIE
COUNTY PA TO START THE DAY. HOWEVER, A WAVE OF ENERGY WILL CURL
AROUND THE LARGER UPPER TROUGH AND THIS MAY ALLOW FOR THE FLOW TO
VEER MORE TO THE NORTHWEST AND ALLOW FOR MORE WIDESPREAD LAKE EFFECT
SNOW INTO THE BROADER NE OH/NW PA SNOW BELT FOR EARLY NEXT WEEK.
THEREFORE, WILL HAVE A LARGE AREA OF LIKELY OR HIGHER POPS ACROSS
THE REGION FOR SUNDAY THROUGH TUESDAY AND SUSPECT SEVERAL MORE
INCHES OF SNOW WILL BE EXPECTED ACROSS THE REGION AND SOME FORM OF A
WINTER HEADLINE WILL NEED TO BE CONSIDERED, AS HINTED AT WITH THE
WINTER STORM WATCH ISSUANCE THROUGH MONDAY AM. TEMPERATURES WILL
REMAIN COLD FOR THE FIRST DAYS OF DECEMBER WITH HIGHS LIKELY NOT
EXCEEDING THE FREEZING MARK ALL THREE DAYS AND LOWS IN THE TEENS
THROUGHOUT THE PERIOD.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
CEILINGS LOWERING TO FL100 AND SHOULD STAY THERE FOR A FEW HOURS
BEFORE CONTINUING THEIR DOWNWARD TRACK AFTER 00Z THURSDAY. AT
THAT TIME, LOW PRESSURE MOVING INTO THE OHIO VALLEY, BUT
REMAINING SOUTH OF THE AREA. RAIN WILL OVERSPREAD THE REGION
AROUND THIS TIME AS WELL. TEMPERATURES DROPPING TO NEAR FREEZING
CHANGES THE PRECIPITATION TYPE TO LIGHT SNOW OR A RAIN/SNOW MIX
FOR TERMINALS AWAY FROM THE LAKESHORE AND ALSO EXCLUDING TOL
WHICH WILL STAY DRY/VFR. EXPECT BOTH CEILINGS AND VISIBILITIES
TO GO TO IFR OR WORSE WITHIN 3-5 HOURS AFTER PRECIPITATION
ONSET. SOUTHWEST WINDS BECOME SOUTHERLY LESS THAN 10KTS.
OUTLOOK...NON-VFR LIKELY IN PERIODIC LAKE EFFECT SNOW FROM
THURSDAY NIGHT THROUGH THE WEEKEND. LAKE EFFECT SNOW IS MOST
LIKELY IN THE PRIMARY SNOWBELT OF NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA.
MARINE
SOME RESIDUAL ENHANCED WESTERLY FLOW WILL CONTINUE ACROSS THE LAKE
THIS MORNING AND ALLOW FOR CONTINUED ELEVATED WAVES OVER THE EASTERN
BASIN. WILL CONTINUE TO HAVE THE SMALL CRAFT ADVISORY VALID THROUGH
10 AM THIS MORNING. HIGH PRESSURE TO THE SOUTH WILL CONTINUE TO
CREEP INTO THE AREA AND BACK FLOW ACROSS THE BASIN. LOW PRESSURE
WILL DEVELOP TO THE SOUTH TONIGHT AND WINDS WILL ABRUPTLY FLIP TO
THE NORTH ON THURSDAY AS THE SYSTEM PASSES TO THE SOUTHEAST.
HOWEVER, THIS LOW WILL HELP A COLD FRONT ACROSS THE LAKE ON THURSDAY
AND FLOW WILL EVENTUALLY SETTLE ON A WESTERLY FLOW FOR FRIDAY. A
GENERAL TROUGH PATTERN WILL SET UP ACROSS THE REGION FOR FRIDAY AND
BEYOND WITH SUSTAINED COLD ALLOWING FOR BOUTS OF LAKE EFFECT SNOW
ACROSS THE BASIN. THE TROUGH AND SNOW WILL ALLOW FOR ENHANCED
WESTERLY FLOW ON FRIDAY THROUGH THE WEEKEND AND THERE WILL LIKELY BE
THE NEED FOR SOME FORM OF MARINE HEADLINE WITH WINDS POSSIBLY
EXCEEDING 20 KT AND WAVES BUILDING ABOVE 4 FT.
CLE WATCHES/WARNINGS/ADVISORIES
OH...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH MONDAY
MORNING FOR OHZ012-014-089.
PA...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH MONDAY
MORNING FOR PAZ001>003.
MARINE...NONE.
SYNOPSIS...26
NEAR TERM...JASZKA/26
SHORT TERM...SEFCOVIC
LONG TERM...SEFCOVIC
AVIATION...26
MARINE...SEFCOVIC
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