767  
FXUS61 KCLE 211029  
AFDCLE  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CLEVELAND OH  
629 AM EDT MON OCT 21 2019  
   
SYNOPSIS
 
 
A SURFACE LOW TRACKS NORTHEASTWARD FROM THE UPPER MIDWEST TO WESTERN  
LAKE SUPERIOR BY TUESDAY MORNING, THEN NORTH-NORTHEASTWARD TO  
NORTHERN ONTARIO THROUGH TUESDAY EVENING. A WARM FRONT ASSOCIATED  
WITH THIS LOW PRESSURE SYSTEM WILL MOVE NORTHEASTWARD OVER OUR  
REGION THIS EVENING THROUGH THE PREDAWN HOURS OF TUESDAY, WHILE  
A COLD FRONT SWEEPS EAST ACROSS THE LOCAL AREA LATE THIS  
EVENING THROUGH TUESDAY MORNING. TROUGHING PERSISTS OVER OUR  
AREA THE REST OF TUESDAY AND WEDNESDAY.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
OUR NEAR-TERM FORECAST REMAINS VALID. NO UPDATES NECESSARY AT  
THIS TIME.  
 
PREVIOUS DISCUSSION...FLOW ALOFT BECOMES PROGRESSIVELY  
SOUTHWESTERLY OVER OUR CWA TODAY THROUGH TUESDAY AS A SHORTWAVE  
HIGH PRESSURE RIDGE EXITS TO OUR EAST AND A LONGWAVE TROUGH  
BEGINS OVERSPREADING THE LOCAL AREA FROM THE CENTRAL UNITED  
STATES. AT THE SURFACE, OVERALL AND GRADUAL SURFACE PRESSURE  
FALLS OCCUR ACROSS NORTHERN OH AND NORTHWEST PA TODAY AS A  
SURFACE LOW TRACKS FROM NEAR THE SOUTHEAST SD/NORTHEAST NE  
BORDER EARLY THIS MORNING TO NEAR WEST-CENTRAL WI BY MIDNIGHT  
TONIGHT. THIS LOW WILL THEN TRACK TO NEAR NORTHERN LAKE SUPERIOR  
BY NIGHTFALL ON TUESDAY. A WARM FRONT ACCOMPANYING THIS LOW  
SHOULD CROSS OUR CWA FROM SOUTHWEST TO NORTHEAST THIS EVENING  
AND THE PREDAWN HOURS OF TUESDAY, WHILE THE COLD FRONT SHOULD  
FOLLOW QUICKLY AND CROSS THE CWA LATE THIS EVENING THROUGH  
TUESDAY MORNING. IN ADDITION, A WARM CONVEYOR BELT WILL CROSS  
OUR CWA FROM WEST TO EAST AHEAD OF THE COLD FRONT. THIS WARM  
CONVEYOR BELT WILL TRANSPORT ABUNDANT MOISTURE NORTHWARD FROM  
THE GULF OF MEXICO AND UNDERGO ISENTROPIC LIFT OVER OUR AREA.  
LASTLY, SURFACE TROUGHING PERSISTS OVER OUR CWA BEHIND THE COLD  
FRONT.  
 
CLOUD COVER INCREASES GENERALLY FROM WEST TO EAST TODAY, WHILE  
SCATTERED TO WIDESPREAD RAIN SHOWERS OVERSPREAD OUR FORECAST AREA  
FROM WEST TO EAST THIS AFTERNOON AND EVENING. THESE SHOWERS WILL BE  
HEAVY AT TIMES. THERE MAY BE JUST ENOUGH INSTABILITY FOR A FEW WEAK,  
BRIEF THUNDERSTORMS WITHIN THE WARM CONVEYOR BELT AND ALONG THE COLD  
FRONT, BUT THE POTENTIAL FOR THUNDERSTORMS REMAINS VERY LOW. THE  
SWATH(S) OF RAIN AND ANY EMBEDDED THUNDERSTORMS WILL END FROM WEST  
TO EAST TUESDAY MORNING AND EARLY AFTERNOON, WHILE PARTIAL AND  
GRADUAL CLEARING WILL ALSO WORK ITS WAY EAST DURING THE COURSE OF  
TUESDAY. THIS WIDESPREAD RAINFALL SHOULD TOTAL AROUND 0.50" TO  
0.75". AS COLD AIR DEEPENS OVER WARM LAKE ERIE, A WELL-ALIGNED  
SOUTHWESTERLY LOW-LEVEL FLOW MAY BEGIN TO TRIGGER SOME LAKE  
EFFECT RAIN SHOWERS OVER THE CENTRAL PORTION OF THE LAKE BY  
EARLY TUESDAY EVENING. HOWEVER, ANY LAKE EFFECT RAIN SHOULD BE  
OFFSHORE NORTHEAST OH AND NORTHWEST PA AT THAT POINT.  
 
DESPITE INCREASING CLOUD COVER TODAY, STRENGTHENING SOUTHEASTERLY TO  
SOUTHERLY SURFACE WINDS WILL RESULT IN WARM ADVECTION REGION-WIDE  
AND DOWNSLOPE FLOW FOR SOME AREAS. THUS, WE STILL EXPECT AFTERNOON  
HIGHS TO REACH THE UPPER 60'S TO MID 70'S. TONIGHT THROUGH TUESDAY,  
SOUTHERLY SURFACE WINDS WILL SHIFT TO SOUTHWESTERLY WITH THE PASSAGE  
OF THE COLD FRONT AND THESE WINDS WILL BE GUSTY. A WIND ADVISORY HAS  
BEEN ISSUED FOR NORTHERN ERIE COUNTY, PA FROM 8 PM THIS EVENING TO 6  
AM EDT TUESDAY. HERE, SOUTHEASTERLY DOWNSLOPE WINDS ARE EXPECTED TO  
GUST UP TO 50 MPH BETWEEN ROUGHLY I-90 AND THE LAKESHORE. GUSTY  
WINDS AND ABUNDANT CLOUD COVER WILL CONTRIBUTE TO MILD LOWS IN  
THE UPPER 40'S TO MID 50'S AROUND DAYBREAK TUESDAY, WITH THE  
COOLEST READINGS IN THE FAR-WEST AND WARMEST READINGS FARTHER  
EAST. AFTERNOON HIGHS ON TUESDAY ARE FORECAST TO REACH THE UPPER  
50'S TO LOWER 60'S, WITH THE COOLEST READINGS IN THE FAR-WEST  
AND HIGHER TERRAIN OF NORTHWEST PA.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/
 
 
BY TUESDAY NIGHT THE AREA WILL BE SANDWICHED BETWEEN THE FILLING LOW  
ACROSS ONTARIO AND HIGH PRESSURE ACROSS THE GULF COAST STATES.  
REMAINING LAKE EFFECT RAIN SHOWERS WILL BE PRIMARILY OFFSHORE, BUT  
WILL CONTINUE THE MENTION OF SHOWERS RIGHT ALONG THE LAKESHORE.  
RIDGING BUILDS IN TOWARD WEDNESDAY MORNING AND BY MIDDAY WEDNESDAY  
WE SHOULD BE DONE WITH THE LAKE EFFECT. THE REST OF THE AREA WILL BE  
FAIR WITH SEASONABLE TEMPERATURES. SOME WARM ADVECTION WILL AID  
TEMPERATURES THURSDAY AND WILL SEE A NUMBER OF LOCATIONS WITH LOWER  
60S. THERE ARE NOTABLE DIFFERENCES WITH THE TIMING AND AVAILABLE  
MOISTURE FOR THE NEXT COLD FRONT EXPECTED TO BE HERE  
THURSDAY/THURSDAY NIGHT/FRIDAY.  
 

 
   
LONG TERM /FRIDAY THROUGH SUNDAY/
 
 
WILL HAVE TO CONTEND WITH THE MODELS RESOLVING THE NEXT SHORTWAVE TO  
CARVE ITS WAY ACROSS THE NORTHERN ROCKIES, PLAINS AND MIDWEST TO END  
THE WEEK. HAVE SIDED CLOSER TO THE ECMWF WHICH SEPARATES THE ENERGY  
LEAVING A CLOSED LOW BEHIND ACROSS THE SOUTHERN PLAINS AND MORE  
QUICKLY TAKES A SHALLOWER NORTHERN SHORTWAVE ACROSS THE GREAT LAKES  
FRIDAY. WILL MAXIMIZE PRECIP CHANCES ON LATER THURSDAY NIGHT AND  
FRIDAY FOR NOW WITH THE SURFACE FRONT NEARBY. WITH MORE OF A  
GLANCING SHOT AT COLD AIR, WILL KEEP PRECIP TYPE ALL RAIN FOR ANY  
LINGERING SHOWERS LATE FRIDAY NIGHT. WILL ALLOW FOR BRIEF HIGH  
PRESSURE SATURDAY, BUT SUNDAY'S FORECAST IS MORE UNCERTAIN.  
 

 
   
AVIATION /12Z MONDAY THROUGH FRIDAY/
 
 
SOUTHEASTERLY SURFACE WINDS SHOULD BECOME GUSTY BY ABOUT  
15Z/MON. A WARM FRONT SHOULD SWEEP NORTHEASTWARD OVER THE AREA  
THIS EVENING THROUGH EARLY TUESDAY MORNING, WHILE AN EASTWARD-  
MOVING COLD FRONT SHOULD REACH A KTOL TO KFDY LINE AROUND  
03Z/TUE AND NEAR THE OH/PA BORDER BY 12Z/TUE. SOUTHEASTERLY  
SURFACE WINDS SHIFT TO SOUTHERLY WITH THE PASSAGE OF THE WARM  
FRONT. THESE SOUTHERLY SURFACE WINDS WILL THEN SHIFT TO  
SOUTHWESTERLY WITH THE PASSAGE OF THE COLD FRONT AND REMAIN  
GUSTY. WIND GUSTS SHOULD AVERAGE 20 TO 30 KNOTS, BUT SHOULD  
REACH 40 KNOTS OR SO AT/NEAR KERI BETWEEN 00Z/TUE AND 12Z/TUE.  
 
VFR ARE EXPECTED AHEAD OF THE UPCOMING RAINFALL. RAIN SHOWERS  
WILL GRADUALLY OVERSPREAD THE REGION FROM WEST TO EAST BETWEEN  
18Z/MON AND 10Z/TUE. CEILINGS SHOULD TREND MVFR WITH THIS RAIN,  
WITH THE POTENTIAL FOR POCKETS OF IFR CEILINGS AND MVFR  
VISIBILITY IN HEAVIER SHOWERS. THERE IS A SLIGHT CHANCE FOR A  
FEW THUNDERSTORMS, BUT FORECAST CONFIDENCE IN THUNDERSTORM  
DEVELOPMENT REMAINS VERY LOW. RAIN SHOULD END WITHIN SEVERAL  
HOURS FOLLOWING THE COLD FRONTAL PASSAGE. THUS, RAIN IS  
FORECAST TO END AROUND 04Z/TUE AT KTOL AND KFDY AND SHOULD END  
BY 12Z/TUE AS FAR EAST AS KCLE.  
   
OUTLOOK
 
NON-VFR POSSIBLE IN WIDESPREAD SHOWERS THROUGH  
TUESDAY MORNING. NON-VFR POSSIBLE IN LAKE EFFECT RAIN SHOWERS  
AT/NEAR KERI TUESDAY EVENING INTO WEDNESDAY. SCATTERED SHOWERS  
MAY RESULT IN NON-VFR THURSDAY AFTERNOON INTO FRIDAY.  
 

 
   
MARINE
 
 
SOUTHEAST WINDS WILL STEADILY INCREASE TODAY. BIGGEST CONCERN FOR  
SMALL CRAFT ADVISORY CONDITIONS COMES WITH STRONGER WINDS THIS  
EVENING/TONIGHT EAST OF WILLOWICK AND ESPECIALLY OFF OF ERIE, PA  
WITH DOWNSLOPE WINDS ADDING TO THE GUSTINESS NEAR THE SHORE. THE  
COLD FRONT CROSSES OVERNIGHT/THROUGH EARLY TUESDAY MORNING.  
SOUTHWEST WINDS IN ITS WAKE WILL BE ENOUGH TO NECESSITATE A SMALL  
CRAFT ADVISORY FOR THE ENTIRE LAKE TUESDAY AND WEDNESDAY. WILL  
LIKELY PUSH 30 KNOTS AT TIMES DURING THE TUE/WED WINDOW, BUT DO NOT  
SEE GALES. WINDS COME DOWN A NOTCH WEDNESDAY NIGHT AHEAD OF THE NEXT  
COLD FRONT THAT WILL ARRIVE FOR THURSDAY. EXPECT A WIND SHIFT TO THE  
NORTHWEST FOR FRIDAY.  
 

 
   
CLE WATCHES/WARNINGS/ADVISORIES
 
 
OH...NONE.  
PA...WIND ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT TUESDAY FOR  
PAZ001.  
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT  
TUESDAY FOR LEZ147>149.  
 

 
 

 
SYNOPSIS...JASZKA  
NEAR TERM...JASZKA  
SHORT TERM...OUDEMAN  
LONG TERM...OUDEMAN  
AVIATION...JASZKA  
MARINE...OUDEMAN  
 
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