781
FXUS61 KCLE 290950
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
450 AM EST FRI NOV 29 2024
SYNOPSIS
A LOW PRESSURE SYSTEM NORTH OF THE REGION WILL KEEP A SURFACE TROUGH
ACROSS THE AREA INTO THE START OF NEXT WEEK. ANOTHER LOW PRESSURE
WILL MOVE EAST ACROSS THE NORTHERN GREAT LAKES, IMPACTING THE AREA
AGAIN FOR MID-WEEK.
NEAR TERM /THROUGH SATURDAY/
THE IMPACTFUL LAKE EFFECT SNOW SYSTEM IS UPON US WITH RADAR SHOWING
A BAND OF HEAVY SNOWFALL MOVING EAST ACROSS PORTIONS OF LAKE AND
ASHTABULA COUNTIES WITH LIGHTER SNOW BEING OBSERVED ELSEWHERE IN THE
SNOWBELT. THIS WILL ESSENTIALLY BE THE NAME OF THE GAME THROUGH THIS
ENTIRE PERIOD AS A DOMINANT SURFACE TROUGH AND BROAD UPPER LEVEL LOW
LINGERS ACROSS THE AREA. WITHOUT REHASHING THE MESOSCALE ENVIRONMENT
PRESENT (SEE END OF THIS SECTION FOR A SYNOPSIS OF THESE) ACROSS
NEOH AND NWPA WITH THIS UPDATE, HERE IS A SUMMARY OF WHAT HAS
CHANGED FOR TODAY INTO SATURDAY:
- MODELS HAVE TRENDED A BIT HIGHER WITH QPF VALUES ACROSS THE
SNOWBELT, WITH TOTAL QPF THROUGH SATURDAY IN THE 1.5-2" RANGE.
HIGHEST VALUES ARE ACROSS EASTERN LAKE COUNTY, ASHTABULA, AND
ERIE PA.
- WITH STRONG MESOSCALE SUPPORT, THE INCREASED QPF VALUES HAVE
RESULTED IN AN INCREASE IN SNOWFALL TOTAL WITH THE MAX VALUES
NEAR 28" ACROSS ASHTABULA & ERIE PA. IN LAKE COUNTY, NORTHERN
GEAUGA, AND NORTHERN CRAWFORD, SNOWFALL TOTALS RANGE 8-20".
THERE WILL BE A NOTABLE NORTH TO SOUTH TAPER IN SNOWFALL
TOTALS, WITH THE HIGHEST TOTALS FURTHER NORTH. IN CUYAHOGA
COUNTY, 4-6" IS STILL EXPECTED IN THE FAR EASTERN PORTION OF
THE COUNTY.
- MODEST CAPE VALUES AND OMEGA LIFT SHOULD RESULT IN AREAS OF
ENHANCED VERTICAL GROWTH WITHIN THE BAND. AS A RESULT, WOULD
NOT BE SURPRISED TO SEE A FEW RUMBLES OF THUNDER OCCUR AND
OPTED TO ADD SLIGHT CHANCE ACROSS THE SNOWBELT THIS AFTERNOON.
- LATE FRIDAY INTO SATURDAY, THERE HAS BEEN A NOTABLE SHIFT IN
THE TIMING OF THE WIND SHIFT ACROSS THE LAKE, ULTIMATELY
IMPACTING THE TIMING OF THE LAKE EFFECT BAND SHIFTING NORTH
OVER THE LAKE. PREVIOUS MODELS ALONG WITH THE 00Z REGIONAL
CANADIAN HAVE WINDS QUICKLY BACKING AND SHIFTING THE DOMINANT
BAND NORTH QUICKER. HOWEVER, HI-RES GUIDANCE SUGGESTS SLOWER
BACKING OF THE WINDS, KEEPING THE BAND ACROSS NE OH & NW PA
LONGER. OPTED TO TREND THIS FORECAST WITH MORE OF THE HI-RES
GUIDANCE, WHICH IS A BIG CAUSE OF THE INCREASED SNOWFALL
TOTALS OVER NWPA THROUGH SATURDAY. WILL CONTINUE TO MONITOR,
BUT IF WINDS DO SHIFT QUICKER, EXPECTED A COUPLE INCHES LESS.
THE ROBUSTNESS OF THIS SYSTEM IS STILL EXPECTED TO RESULT IN
SNOWFALL RATES OF 1-2"/HR, WITH THE HIGHEST RATES EXPECTED THIS
AFTERNOON. IN ADDITION, WEST WINDS OF 15-25 MPH WITH GUSTS UP TO
35- 40 MPH WILL RESULT IN AREAS OF BLOWING SNOW WHICH WILL
RESULT IN DRIFTING SNOW AND THE POTENTIAL FOR QUICKLY REDUCED
VISIBILITIES. THESE WINDS WILL WEAKEN A BIT AFTER 00Z SATURDAY,
ALTHOUGH CANNOT RULE OUT ADDITIONAL BLOWING SNOW INTO SATURDAY,
ESPECIALLY ALONG THE IMMEDIATE LAKESHORE.
OUTSIDE OF THE SNOWBELT, THE ENTIRE AREA WILL REMAIN UNDER THE
INFLUENCE OF THE BROAD UPPER LEVEL LOW, KEEPING THE POTENTIAL OF
SCATTERED SNOW SHOWERS POSSIBLE ACROSS THE AREA FOR TODAY. NWOH WILL
HAVE THE HIGHEST CHANCE OF RECEIVING MEASURABLE SNOW AS LAKE EFFECT
SNOWBANDS OFF OF LAKE MICHIGAN POTENTIALLY TRAVEL FAR ENOUGH EAST
FOR AREAS AROUND TOLEDO TO GET AROUND 0.5". WILL HAVE TO CONTINUE TO
MONITOR THE TREND IN SNOWBANDS UPSTREAM FOR A BETTER IDEA OF
POTENTIAL IMPACTS TO THE AREA. IN ADDITION, GUSTY WINDS FROM THE
WEST WILL INCREASE TODAY TO BE SUSTAINED AT 15-25 MPH, GUSTING UP TO
30-40 MPH. THE STRONGEST WINDS ARE EXPECTED ALONG AND WEST OF I71
AND ALONG THE LAKESHORE. THESE WINDS WILL GRADUALLY WEAKEN AFTER 00Z
TONIGHT WITH SUSTAINED WINDS OF 10-15 MPH, GUSTING UP TO 30 MPH
POSSIBLE. TEMPERATURES THROUGH THIS PERIOD ARE MUCH COOLER THAN
RECENT HIGHS, ONLY CLIMBING INTO THE LOW 30S TODAY AND THE MID TO
UPPER 20S ON SATURDAY. FRIDAY NIGHT LOWS WILL DROP INTO THE UPPER
TEENS TO LOW 20S.
HERE IS A QUICK RECAP OF THE MESOSCALE SET-UP FOR THE LAKE EFFECT
SNOWBANDS...
A VERY COLD AIRMASS WITH 850MB TEMPERATURES OF -12 TO - 14C
WILL PUSH EAST ACROSS A RELATIVELY WARM LAKE ERIE (UPPER 40S IN
FAHRENHEIT) WHICH WILL CREATE STRONG LAKE INDUCED INSTABILITY
THIS AFTERNOON. SIMULTANEOUSLY, EQL WILL DEEPEN TO APPROXIMATELY
20KFT WITH A STRONG CONVERGENT BOUNDARY DEVELOPING ALONG THE
LAKE SHORE. ADDITION OMEGA LIFT AND STRENGTHENING LAPSE RATES
WILL ALL FOR A WELL DEVELOPED LINE OF LAKE EFFECT SNOW SHOWERS
TO MOVE INLAND WITH QPF TOTALS OF 1.5-2" EXPECTED. THIS SET-UP
IS EXTREMELY CONDUCIVE TO HEAVY LAKE EFFECT BANDS SETTING UP.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
SIMPLY PUT, THE SHORT TERM FORECAST PERIOD WILL BE AN ADDITIONAL TWO
AND HALF DAYS OF A MULTI-DAY LAKE EFFECT SNOW OUTBREAK ACROSS THE
GREAT LAKES REGION. UNFORTUNATELY, THERE ARE STILL SOME CONDITIONAL
COMPONENTS TO THE FORECAST FOR THE LOCAL AREA AND DETAILS WILL
BECOME MORE CLEAR OVER THE NEXT 24 HOURS.
FOR THE SATURDAY NIGHT FORECAST, THE QUESTION REMAINS ABOUT HOW
STRONG THE TROUGH OVER THE LAKE AND BACKED FLOW WILL BE TO KEEP THE
MAIN HEAVY LAKE EFFECT SNOW BAND OVER THE LAKE OR IF THERE WILL BE
SOME SLIGHT WEAKENING TO ALLOW FOR THE BAND TO SINK BACK SOUTH INTO
THE LAKESHORE OF NW PA AND NE OH ON SATURDAY NIGHT. THE REGIONAL
CANADIAN MODEL CONTINUES TO PREFER THE OFFSHORE SOLUTION AND HAVE
BIASED THE FORECAST WITH BEING MOSTLY OFFSHORE AND PERHAPS A
GLANCING 1 TO 3 INCHES OF SNOW AT WORST.
FOR SUNDAY AND SUNDAY NIGHT, THE UPPER LEVEL PATTERN EVOLVES AND
ALLOW FOR THE MAIN TROUGH AXIS TO MOVE ACROSS THE AREA, ALLOWING FOR
THE MEAN FLOW TO VEER TO NORTH OF WEST. THIS SHOULD ALLOW FOR THE
HEAVY LAKE EFFECT SNOW BAND TO PUSH BACK SOUTH AT SOME POINT ON
SUNDAY AND BRING ADDITIONAL SNOW ACCUMULATIONS TO NE OH AND NW PA.
THE THERMODYNAMIC PROFILES CONTINUE TO LOOK FAVORABLE FOR EFFECTIVE
LAKE EFFECT SNOW WITH 1 TO 2 INCH PER HOUR SNOWFALL RATES. HOWEVER,
THERE WILL LIKELY BE MORE PERIODIC SQUALLS VS. A MAIN SEMI-PERMANENT
BAND AS THE UPPER TROUGH WILL PRESENT SOME WIND SHEAR TO PARTIALLY
DISRUPT BANDS AND THE FLOW WILL SHORTEN THE FETCH OVER THE LAKE,
FAVORING MORE WIDESPREAD, MULTI-BANDED SNOW.
ANOTHER SHORTWAVE WILL MOVE THROUGH THE GREAT LAKES REGION ON
MONDAY. THIS WAVE WILL BRING SOME EVEN COLDER AIR INTO THE REGION,
WHICH SHOULD ALLOW FOR SOME ENHANCED LAKE INDUCED INSTABILITY FOR
LAKE EFFECT. HOWEVER, SOME DRIER, CONTINENTAL AIR WILL TRY TO GET
INTO THE REGION AND PERHAPS ALLOW FOR LESS EFFICIENT LAKE EFFECT.
THEREFORE, THE HIGHER SNOW AMOUNTS WILL BE LARGELY DEPENDENT ON ANY
UPSTREAM CONNECTIONS, ESPECIALLY LAKE HURON.
OVERALL, THERE WILL LIKELY NEED TO BE SOME FORM OF A WINTER WEATHER
HEADLINE FOR SUNDAY AND MONDAY WITH THE THREAT FOR ADDITIONAL LAKE
EFFECT SNOW. THE ONGOING LAKE EFFECT SNOW HEADLINES WILL BE
EVALUATED OVER THE NEXT 24 HOURS AND EITHER EXTENDED INTO NEXT WEEK
OR REPLACED WITH A NEW SET OF HEADLINES TO APPROPRIATELY ADDRESS THE
THREAT. TEMPERATURES WILL REMAIN BELOW NORMAL WITH HIGHS IN THE
LOWER 30S AND LOWS IN THE TEENS. NIGHTTIME WIND CHILL VALUES MAY
REACH SINGLE DIGITS AT TIMES.
LONG TERM /TUESDAY THROUGH THURSDAY/
THE PATTERN ACROSS THE REGION WILL CHANGE BEYOND MONDAY FOR THE
FORECAST AREA. HOWEVER, THERE IS SOME MODEL TIMING DISAGREEMENT WITH
THE ECMWF AND RGEM BEING FASTER WITH THE PATTERN CHANGE AND THE GFS
BEING SLOWER. THE BROADER UPPER TROUGH PATTERN OVER THE EASTERN
NORTH AMERICAN CONTINENT WILL START TO PROGRESS EASTWARD AND A WAVE
OF ENERGY WILL RIPPLE THROUGH THE BACK SIDE OF THIS TROUGH AND
THROUGH THE GREAT LAKES REGION. THIS WILL BRING SOME COOLER AIR INTO
THE REGION AND FLARE UP ANY LAKE EFFECT SNOW AS A COLD FRONT MOVES
THROUGH THE REGION. SOME RIDGING ALOFT WILL ENTER AND BACK FLOW
ACROSS THE REGION AND ALLOW FOR SOME WARMER TEMPERATURES, SHUTTING
OFF THE LAKE EFFECT SNOW. ANOTHER LARGER TROUGH WILL DIG INTO THE
GREAT LAKES REGION LATER IN THE WEEK AND BRING ANOTHER ROUND OF SNOW
TO THE FORECAST AREA. TEMPERATURES WILL BE BELOW NORMAL FOR THE
PERIOD WITH HIGHS STAYING IN THE 30S.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
WIDESPREAD CLOUD COVER WILL PERSIST THROUGH THIS PERIOD AS AN
UPPER LEVEL TROUGH AND A STRONG LAKE EFFECT SYSTEM IMPACT THE
AREA. TO START, OVERNIGHT SKIES WILL LINGER PRIMARILY IN MVFR
HEIGHTS. THE EXCEPTION IS ACROSS THE SNOWBELT, INCLUDING KERI,
WHERE CEILINGS HAVE LOWERED TO HIGH END IFR HEIGHTS, WHICH WILL
LIKELY REMAIN THE CASE THROUGH THIS PROLONGED LAKE EFFECT SNOW
EVENT. IN ADDITION, ALL TERMINALS HAVE THE POTENTIAL TO BE
IMPACTED BY A FEW SNOW SHOWERS, WHICH WILL LIKELY REDUCE
VISIBILITIES BRIEFLY TO 3-5SM AT TIMES. AGAIN THE EXCEPTION WILL
BE IN THE SNOWBELT WHERE HEAVY SNOW WILL DROP VISIBILITIES AS LOW
AS 1/4SM. WILL HAVE TO MONITOR KTOL FOR DIMINISHED CONDITIONS AS
THE TERMINAL HAS THE POTENTIAL TO BE IMPACTED FROM UPSTREAM LAKE
EFFECT OFF OF LAKE MICHIGAN, BUT WITH LOW CONFIDENCE OPTED TO
NOT INCLUDE WITH THIS UPDATE.
WEST WINDS OF 8-12 KNOTS WITH GUSTS UP TO 25 KNOTS THIS MORNING
WILL CONTINUE TO INCREASE INTO THIS AFTERNOON. WINDS THIS
AFTERNOON WILL MAINTAIN THE WESTERLY COMPONENT BUT STRENGTHEN TO
15-20 KNOTS SUSTAINED WITH GUSTS 25-30 KNOTS POSSIBLE THROUGH
00Z SATURDAY. THE STRONGEST GUSTS SHOULD BE ACROSS WESTERN
TERMINALS AND ALONG THE LAKESHORE. WINDS WEAKEN AFTER 00Z TO
10-13 KNOTS FROM THE WEST-SOUTHWEST WITH GUSTS ISOLATED TO
WESTERN AND LAKESHORE TERMINALS OF 20-25 KNOTS.
OUTLOOK...NON-VFR LIKELY IN PERIODIC LAKE-EFFECT SNOW IS
EXPECTED 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
BEHIND A COLD FRONT, A TROUGH WILL SET UP ACROSS THE GREAT LAKES
REGION TODAY AND PERSIST INTO EARLY NEXT WEEK. COLD AIR OVER THE
LAKES ALONG WITH THE BROAD TROUGH PATTERN WILL ALLOW FOR SIGNIFICANT
LAKE EFFECT SNOW TO DEVELOP OVER THE LAKE. THIS WILL ALSO ALLOW FOR
THE TROUGH TO LOCALLY STRENGTHEN OVER THE LAKE THROUGH THE PERIOD
AND STRONG WESTERLY FLOW WILL BE EXPECTED. THEREFORE, A SMALL CRAFT
ADVISORY REMAINS FOR THE LAKE AND AREAS EAST OF THE LAKE ERIE
ISLANDS MAY SEE THIS HEADLINE EXTENDED FURTHER INTO MIDDLE-TO-END OF
THE WEEK, AS THESE STRONGER WESTERLY WINDS WILL PERSIST FOR MOST OF
THE WEEK. STRONG WEST WINDS WILL POSE A LOW WATER THREAT FOR THE
WESTERN BASIN OF LAKE ERIE THIS EVENING INTO TONIGHT AND WILL
MAINTAIN THE LOW WATER ADVISORY.
CLE WATCHES/WARNINGS/ADVISORIES
OH...WINTER WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR OHZ011.
LAKE EFFECT SNOW WARNING UNTIL 10 AM EST SATURDAY FOR
OHZ012>014-089.
PA...LAKE EFFECT SNOW WARNING UNTIL 10 AM EST SATURDAY FOR
PAZ001>003.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SATURDAY FOR LEZ142-143.
LOW WATER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 PM EST
SATURDAY FOR LEZ142>144-162>164.
SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LEZ144>149.
SYNOPSIS...CAMPBELL
NEAR TERM...CAMPBELL
SHORT TERM...SEFCOVIC
LONG TERM...SEFCOVIC
AVIATION...CAMPBELL
MARINE...SEFCOVIC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page