701
FXUS61 KCLE 170042
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
742 PM EST THU JAN 16 2025
SYNOPSIS
A WEAK TROUGH LINGERS OVER THE LAKE ERIE REGION AND UPPER OHIO
VALLEY THIS EVENING BEFORE AN EASTWARD-MOVING RIDGE IMPACTS OUR
REGION ON FRIDAY. THIS RIDGE EXITS EASTWARD FRIDAY NIGHT AS A COLD
FRONT APPROACHES FROM THE WESTERN GREAT LAKES. THIS STRONG COLD
FRONT WILL SWEEP EASTWARD THROUGH OUR AREA ON SATURDAY AND BE
FOLLOWED BY A RIDGE BUILDING FROM THE NORTHERN GREAT PLAINS THROUGH
THE REST OF THIS WEEKEND. HOWEVER, BEHIND THE FRONT, A TROUGH WILL
LIKELY FORM OVER AND VERY NEAR THE GREAT LAKES.
NEAR TERM /THROUGH FRIDAY NIGHT/
CYCLONIC W'ERLY TO NW'ERLY FLOW ALOFT, EMBEDDED SHORTWAVE
DISTURBANCES, AND A WEAK SURFACE TROUGH AFFECT OUR REGION THROUGH
THIS EVENING. DURING THE PREDAWN HOURS OF FRIDAY MORNING, A RIDGE AT
THE SURFACE AND ALOFT BUILDS FROM THE WESTERN GREAT LAKES AND UPPER
MIDWEST. PERIODIC SNOW SHOWERS, LIGHT TO OCCASIONALLY MODERATE IN
INTENSITY, ARE EXPECTED THROUGH THIS EVENING COURTESY OF MOIST
ISENTROPIC ASCENT PRECEDING THE SHORTWAVE TROUGH AXES AND LOW-LEVEL
CONVERGENCE/MOIST ASCENT ALONG ATTENDANT SURFACE TROUGH AXES
RELEASING WEAK POTENTIAL INSTABILITY IN THE LOWEST 1 KM AGL. A
SUFFICIENTLY-COLD/MOIST LOW/MID-LEVEL ATMOSPHERE OVER AND DOWNWIND
OF THE ~1C ICE-FREE WATERS OF LAKE ERIE, LAKE SURFACE TO 850 MB
TEMPERATURE DIFFERENCES NEAR 11C, AND THE SEEDER-FEEDER PROCESS ARE
EXPECTED TO ALLOW LAKE-ENHANCED SNOW (LENS) TO OCCUR OVER/DOWNWIND
OF LAKE ERIE THROUGH THIS EVENING. THE LENS WILL OCCUR PRIMARILY
EAST AND SOUTHEAST OF LAKE ERIE SINCE THE EXPECTED WX PATTERN
EVOLUTION AT THE SURFACE AND ALOFT WILL FAVOR W'ERLY TO NW'ERLY MEAN
LOW-LEVEL FLOW. THE LENS WILL PRIMARILY BE LIGHT GIVEN MODEST LAKE-
INDUCED CAPE. HOWEVER, A BURST OF STEADY TO HEAVY LENS WITH SNOWFALL
RATES BRIEFLY REACHING 0.5" TO 1" PER HOUR IS EXPECTED ALONG/NEAR
THE LAKESHORE FROM ROUGHLY NORTHEASTERN CUYAHOGA COUNTY TO ERIE
COUNTY, PA LATE THIS AFTERNOON AND/OR EARLY EVENING AS LOW-LEVEL
CONVERGENCE ALONG THE MAJOR AXES OF LAKE-EFFECT CLOUD BANDING AND
MOIST ISENTROPIC ASCENT AHEAD OF A SHORTWAVE TROUGH AXIS RESULT IN
MODERATE TO STRONG/MAXIMIZED ASCENT IN A CLOUDY DGZ ABOUT 1 KM
THICK. ALSO, THE PASSAGE OF THAT SHORTWAVE TROUGH AXIS WILL CAUSE
SW'ERLY MEAN LOW-LEVEL FLOW OVER/DOWNWIND OF EASTERN LAKE ERIE TO
VEER. AFTER MIDNIGHT TONIGHT, SNOW IS EXPECTED TO END QUICKLY FROM
WEST TO EAST AND ANY LINGERING SNOW IS FORECAST TO END BY DAYBREAK
AS MID/UPPER-LEVEL MOISTURE/CLOUD COVER AND THE SEEDER-FEEDER
PROCESS EXIT E'WARD AND THE AFOREMENTIONED RIDGE IS ACCOMPANIED BY A
LOWERING/STABILIZING SUBSIDENCE INVERSION, WHICH WILL CAUSE MODEST
LAKE-INDUCED CAPE TO WANE FURTHER. ADDITIONAL SNOW ACCUMULATIONS
THROUGH DAYBREAK FRIDAY ARE EXPECTED TO BE A COATING TO 2" IN NE OH
AND 2-4" IN NW PA. LITTLE OR NO FRESH SNOW ACCUMULATION IS EXPECTED
ELSEWHERE. A WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 4 AM FRIDAY
FOR MOST OF NE OH AND UNTIL 7 AM EST FRIDAY FOR NW PA. OVERNIGHT LOW
TEMPERATURES ARE EXPECTED TO REACH THE 20'S AREA-WIDE AROUND
DAYBREAK.
BETWEEN DAYBREAK FRIDAY AND MIDNIGHT FRIDAY NIGHT, OUR REGION WILL
BECOME LOCATED ALONG THE WESTERN FLANK OF THE E'WARD-MOVING RIDGE AT
THE SURFACE AND ALOFT, WHICH WILL ALLOW WAA TO BEGIN IN EARNEST
ACROSS NORTHERN OH AND NW PA. ODDS FAVOR FAIR WEATHER AS STABILIZING
SUBSIDENCE ACCOMPANIES THE RIDGE. THIS SUBSIDENCE SHOULD ALSO RESULT
IN CLOUD BREAKS AND PEEKS OF SUNSHINE. LATE AFTERNOON HIGHS ARE
EXPECTED TO REACH THE LOWER TO MID 30'S IN NW PA AND MAINLY THE MID
TO UPPER 30'S IN NORTHERN OH. DURING FRIDAY EVENING, LOW
TEMPERATURES SHOULD REACH THE MID 20'S TO LOWER 30'S IN NW PA AND
THE UPPER 20'S TO LOWER 30'S IN NORTHERN OH. READINGS ARE THEN
EXPECTED TO MODERATE TO NEAR 35F AREA-WIDE BY DAYBREAK SATURDAY AS
WE REMAIN LOCATED WITHIN THE WAA REGIME ALONG THE WESTERN FLANK OF
THE AFOREMENTIONED RIDGE. AFTER MIDNIGHT FRIDAY NIGHT, MOISTENING
ISENTROPIC ASCENT IS EXPECTED TO ALLOW RAIN AND/OR SNOW TO
OVERSPREAD OUR REGION FROM THE SOUTH AND WEST AS A SHORTWAVE TROUGH
AND ATTENDANT COLD FRONT APPROACH FROM THE UPPER MIDWEST AND
VICINITY. NO SNOW ACCUMULATION IS EXPECTED.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
AN UPPER-LEVEL TROUGH WILL BE MOVING ACROSS THE REGION ON SATURDAY,
WITH PRECIPITATION LIKELY ONGOING ACROSS THE ENTIRE FORECAST AREA
SATURDAY MORNING (CURRENTLY HAVE 90-100% POPS AREAWIDE). THE SURFACE
LOW WILL ACTUALLY BE LOCATED WELL TO THE NORTH NEAR THE GEORGIAN BAY
SO MOST THE AREA WILL BE FULLY ENTRENCHED WITHIN THE "WARM SECTOR"
WITH BREEZY SOUTH WINDS. THERE IS SOME MODEL VARIABILITY WITH REGARD
TO THE SURFACE TEMPERATURES WITHIN THE WARM SECTOR, AFFECTING
PRECIPITATION TYPE. SOME HAVE A COLD 34 TO 36 DEGREE RAIN, WHILE
OTHERS HAVE A WET SNOW OR RAIN/SNOW MIX WITH TEMPERATURES AROUND 32
TO 34. CURRENT SNOWPACK ACROSS MUCH OF THE AREA MAY ALLOW FOR MORE
RAIN/SNOW OR SNOW TO FALL BUT STILL HELD TEMPERATURES AND
PRECIPITATION TYPE TOWARDS THE MIDDLE OF THE PACK. AS THE COLD FRONT
MOVES IN, SHOULD SEE A QUICK TRANSITION TO ALL SNOW THROUGH THE DAY
SATURDAY. OVERALL, TOTAL QPF AND LOW SNOW RATIOS SHOULD RESULT IN
GENERALLY AN INCH OR LESS OF SNOW AREAWIDE, WITH ISOLATED HIGHER
AMOUNTS TO TWO INCHES OR SO IN THE TYPICAL HIGH TERRAIN AREAS IN
NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA.
TEMPERATURES RAPIDLY DROP BEHIND THE DEPARTING COLD FRONT SATURDAY
NIGHT THROUGH SUNDAY NIGHT. TEMPERATURES AT 850MB DROP FROM AROUND -
2 C AT 12Z/SAT TO AROUND -20 C BY 06Z/MON. MEANWHILE, ANOTHER UPPER-
LEVEL TROUGH MOVES ACROSS THE REGION ON SUNDAY, PROVIDING A LITTLE
EXTRA LOW-LEVEL MOISTURE. SHOULD SEE LIGHT, ISOLATED LAKE EFFECT
SNOW STARTING TO DEVELOP SATURDAY NIGHT, GROWING IN INTENSITY AND
AREA SUNDAY AND SUNDAY NIGHT AS INVERSION HEIGHTS DEEPEN AND
MODERATE LAKE-INDUCED INSTABILITY DEVELOPS. ADDITIONAL LOW-LEVEL
MOISTURE FROM THE SYSTEM SHOULD ALSO RESULT IN AT LEAST SCATTERED
SNOW SHOWERS AREAWIDE. MOST OF THE SNOW BELT SHOULD SEE AT LEAST A
COUPLE INCHES THROUGH SUNDAY NIGHT WITH HIGHER AMOUNTS POSSIBLE IN
NORTHWEST PENNSYLVANIA.
LONG TERM /MONDAY THROUGH THURSDAY/
LAKE EFFECT SNOW IS LIKELY TO CONTINUE MONDAY AND TUESDAY, THOUGH
SHOULD GRADUALLY SHIFT NORTHWARD TO CLOSER TO THE LAKESHORE ON
MONDAY AND OFFSHORE LAKE ERIE BY TUESDAY AS STEERING FLOW BECOMES
MORE BACKED (I.E SWITCHING FROM WESTERLY FLOW ON MONDAY TO
SOUTHWEST FLOW ON MONDAY).
THE BIGGEST WEATHER STORY OF THE FORECAST THOUGH IS THE BRUTAL COLD
EXPECTED MONDAY THROUGH WEDNESDAY. COLD ARCTIC AIR BUILDS IN WITH
AIR TEMPERATURES DROPPING TO A RANGE OF 5 TO -5 DEG F BY EARLY
MONDAY MORNING, WITH BREEZY CONDITIONS BRINGING WIND CHILLS DOWN TO
AS LOW AS -15 TO -25. AIR TEMPERATURES GRADUALLY DECREASE TUESDAY
AND WEDNESDAY WITH LOWS DOWN TO AROUND -2 TO -8 TUESDAY MORNING AND -
8 TO -13 WEDNESDAY. WINDS GRADUALLY DECREASE THOUGH, SO SUSTAINED
WIND CHILLS ARE GENERALLY EXPECTED TO REMAIN IN THE -15 TO
-25 RANGE THROUGH AT LEAST WEDNESDAY MORNING. DAYTIME HOURS ARE NOT
EXPECTED TO PROVIDE MUCH RELIEF AS AIR TEMPERATURES REMAIN IN THE
LOW SINGLE DIGITS AND WIND CHILLS STILL LIKELY TO STAY AT OR BELOW -
10.
BROADER SUITE OF ENSEMBLE GUIDANCE HAS REMAINED RELATIVELY
CONSISTENT WITH THE WIND CHILL FORECAST OF AROUND -15 TO -25. ENS
HAS TRENDED A TOUCH COLDER (WITH ABOUT 25% OF MEMBERS SHOWING -30 OR
COLDER WIND CHILLS) WHILE THE THE GEFS HAVE ALSO TRENDED COLDER
(THOUGH STILL REMAIN ON THE WARM SIDE OF ENSEMBLE GUIDANCE), WITH
BOTH TRENDING TOWARDS A SLIGHTLY STRONGER HIGH (CMC IS DOING THE
OPPOSITE, THOUGH THIS LARGELY HASN'T AFFECTED THE WIND CHILL
FORECAST). THE BIGGEST TREND IS TOWARDS COLDER ACTUAL AIR
TEMPERATURES TUESDAY NIGHT INTO WEDNESDAY MORNING WITH ENSEMBLES
BRINGING THE CENTER OF THE HIGH A BIT FARTHER NORTH INTO THE OHIO
VALLEY, ACROSS THE SOUTHERN PART OF OUR FORECAST AREA. IF THIS
HAPPENS, THERE WOULD BE A GOOD CHANCE TO DECOUPLE AND ALLOW FOR
STRONG RADIATIONAL COOLING. OUR SOUTHERN CLIMATE SITES (SUCH AS
MANSFIELD, AKRON-CANTON, AND YOUNGSTOWN) COULD HAVE A SHOT AT
BREAKING DAILY RECORD LOW TEMPERATURES.
FOR HISTORICAL CONTEXT, THIS IS LIKELY TO BE THE COLDEST AIRMASS OUR
REGION HAS SEEN SINCE THE DECEMBER 22-23, 2022 SYSTEM, WHICH BROUGHT
WIND CHILLS OF -30 TO -35. EXTREME IMPACTS WILL POSSIBLE, NOT ONLY
BECAUSE OF HOW COLD IT WILL GET BUT ALSO THE DURATION OF THE COLD.
RESEARCH SUGGESTS THAT'S WHEN REACHING TEMPERATURES OF LESS THAN 16
DEGREES OR LESS FOR 48 HOURS OR LONGER WILL TRIGGER GREATER
INFRASTRUCTURE IMPACTS TO THE AREA SUCH AS:
*FROZEN/BURST PIPES
*DEAD CAR BATTERIES
*IMPROPER USE OF SECONDARY HEAT LEADING TO CARBON MONOXIDE POISONING
*INCREASE IN STRUCTURE FIRES
FOR REFERENCE, WE ARE FORECASTING TEMPERATURES TO REMAIN IN THE
SINGLE DIGITS OR LOWER FOR AT LEAST 60 HOURS SUNDAY NIGHT THROUGH
WEDNESDAY.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
IMPROVING FLIGHT CONDITIONS AS SNOW AND LOW CEILINGS GRADUALLY
EXIT THE REGION. SNOW ONLY IN THE FAR EASTERN TERMINALS AT THIS
HOUR, BUT STILL CARRYING SOME IFR FOR PLACES LIKE TOL/MFD. HIGH
PRESSURE BUILDS IN FROM THE SOUTH AND ENDS THE LAKE EFFECT SNOW
FOR THE MOST PART, WITH ONLY ERI HANGING ON THROUGH 12Z FRIDAY.
VFR WILL TRY TO TAKE HOLD AFTER 18Z FRIDAY, BUT SCOURING ALL OF
THE LOW LEVEL MOISTURE OUT OF THE EASTERN TERMINALS WILL PROVE
TO BE DIFFICULT. WEST WINDS 10KTS BECOME SOUTHWESTERLY INTO
FRIDAY, STRENGTHENING TO 12-15KTS WITH GUSTS TO 20KTS ON THE
BACK END OF THE TAF.
OUTLOOK...NON-VFR EXPECTED WITH PERIODIC RAIN AND/OR SNOW THIS
SATURDAY THROUGH TUESDAY.
MARINE
ICE CONTINUES TO EXPAND WITH MOST OF THE NEARSHORE WATERS ICE COVERS
AND OPEN WATERS WEST OF AVON POINT ICE COVERED AS WELL. FOR WHAT
REMAINS OPEN, WESTERLY WINDS OF 15 TO 20 KNOTS WITH WAVES OF 3 TO 5
FEET CONTINUE THROUGH AT LEAST TONIGHT BEFORE HIGH PRESSURE BUILDS
IN. SOUTHERLY WINDS OF 15 TO 25 KNOTS DEVELOP ON THE BACKSIDE OF THE
DEPARTING HIGH FRIDAY INTO FRIDAY NIGHT WITH 15 KNOT NORTHWEST WINDS
SATURDAY THROUGH SUNDAY.
A BRUTALLY COLD AIRMASS WILL BUILD IN MONDAY THROUGH WEDNESDAY, AND
SHOULD EXPECT RAPIDLY EXPANSION OF ICE COVER ACROSS MOST OF LAKE
ERIE THROUGH THIS TIME PERIOD. SHOULD ALSO SEE STRONG WEST-SOUTHWEST
WINDS OF 20 TO 30 KNOTS ON MONDAY AND TUESDAY, WHICH MAY LEAD TO
HEAVY FREEZING SPRAY FOR ICE-FREE AREAS OF LAKE ERIE.
CLE WATCHES/WARNINGS/ADVISORIES
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR PAZ001>003.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR LEZ147>149.
SYNOPSIS...JASZKA
NEAR TERM...JASZKA
SHORT TERM...SAUNDERS
LONG TERM...SAUNDERS
AVIATION...26
MARINE...SAUNDERS
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