000 FXUS61 KCLE 280347 AFDCLE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 1048 PM EST SAT JAN 27 2007 .UPDATE(TONIGHT)... WILL UPDATE BY 11 PM TO LOWER POPS IN THE TOLEDO AREA. THOUGHT ABOUT LOWERING POPS IN THE LAKESHORE EAST OF CLEVELAND...BUT OPTED AGAINST SINCE LATEST RADAR PICTURES SHOW SOME DEVELOPMENT OVER THE LAKE. PREVIOUS UPDATE DISCUSSION BELOW... NO MAJOR CHANGES ARE PLANNED TO THE FCST. LATEST RADAR PICTURES SHOW A BROKEN BAND OF SNOW EXTENDING FROM THE WESTERN BASIN OF LAKE ERIE EAST INTO THE CITY OF CLEVELAND AND POINTS NEAR THE LAKESHORE. THE RUC AND 18Z NAM SHOW THIS BAND SHIFTING SOUTH THIS EVENING AS THE BOUNDARY WINDS VEER THIS EVENING. BAND MAY ALSO BE HELPED BY SOME UPPER LEVEL DIVERGENCE FROM THE EXITING JET. COULD SEE AN INCH OR TWO FROM LORAIN AND OBERLIN AND EAST...BUT MODEL SOUNDING PROFILES SUGGEST THAT DENDRITIC SNOW GROWTH NOT THAT FAVORABLE. SO...DO NOT EXPECT SNOW/WATER RATIOS TO BE MORE THAN 10-12:1. THINKING THAT 1-2 INCHES FOR THE NORTH (EXCEPT AN INCH OR LESS IN TOLEDO) SEEMS REASONABLE. WILL ALSO EXTEND CATEGORICAL POPS TO LORAIN COUNTY WITH THE BAND IN PLACE. TEMPERATURE PROFILE DOES NOT LOOK VERY FAVORABLE FOR LAKE EFFECT YET. THUS...NOT A GREAT DEAL OF PCPN IN NW PA AT LEAST THIS EVENING. IN FACT...THE LATEST MODEL INFORMATION SUGGESTS VERY LITTLE PCPN THERE WHICH CORRESPONDS WELL TO LATEST RADAR PICTURES. HOWEVER...IT IS EXPECTED THAT AS THE EVENING GOES ON THERE WILL BE SOME LAKE ENHANCEMENT INTO NW PA AS 850MB TEMPS COOL TO -11C BY 12Z. WILL CONTINUE WITH CATEGORICAL POPS IN THE SNOWBELT...BUT LOWER ACCUMS TO 1-2 INCHES. FOR INLAND AREAS...AM CONTINUING WITH SCT SW. WILL HAVE TO WATCH SOME SNOW IN FDY LATE TONIGHT FROM LAKE MICH...BUT AM STILL THINKING AN INCH OR LESS SHOULD COVER IT. AS FOR TEMPS...DEW POINTS STILL IN THE MID-UPPER 20S. ALTHOUGH DRIER AIR IS EXPECTED TO MOVE ACROSS THE AREA OVERNIGHT...AM THINKING THAT TEMPS MAY BE A CATEGORY HIGHER ESPECIALLY WITH THE CLOUDS AND WINDS. NO CHANGES TO HEADLINES EITHER. SHIFTING WINDS SUNDAY AFTERNOON AND NIGHT ARE A LITTLE CONCERNING FOR LARGE ACCUMULATIONS. WINDS FINALLY SETTLE INTO A SINGLE DIRECTION LATE SUN NIGHT BUT BY THEN THE RIDGE IS STARTING TO BUILD IN HELPING TO DRY THE AREA OUT. SHOULD STILL BE COLD ENOUGH FOR LES...AND THERE WILL LIKELY BE A FAIRLY STRONG BAND WITH THE ARCTIC FRONTAL PASSAGE SUN EVENING...BUT IT IS STILL UNCLEAR IF WARNING AMOUNTS WILL BE REACHED. UPDATE OUT BY 945 PM. && .AVIATION(00Z-00Z)... LOT/S OF LIGHT SNOW SHOWING UP IN OBS AND THIS WILL LIKELY CONT THRU THE EVE. SOME FZDZ REPORTED EARLIER AT KERI BUT THREAT FOR THIS NOW GONE AS THE COLDER CLOUDS NEEDED FOR SEEDING FOR SNOW ARE NOW OVERHEAD. CIGS MVR ALL SITES AND CAN/T SEE WHY THEY WOULD CHANGE MUCH OVERNIGHT AND SUNDAY AS COLDER AIR WORKS IN BEHIND SECONDARY COLD FRONT. SNOW HOPEFULLY SHOULD NOT GET OUT OF HAND BUT PLACES LIKE KCLE...KYNG AND KERI WILL LIKELY GO IFR FOR A FEW HOURS LATER TONIGHT. FORECAST SOUNDINGS CONT TO SUGGEST A DRY PERIOD FOR MUCH OF SUN WITH LAKE EFFECT GETTING GOING IN SNOWBELT LATE IN PERIOD. SO WILL MAINLY PUT SOME SNOW IN FOR THE FIRST 6 HOURS OR SNOW THEN NOT MUCH TIL TOMORROW AFT. FLOW SHOULD GRADUALLY BECOME NWLY. && .SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... THE BIG QUESTION IS WHAT KIND OF HEADLINE DO WE NEED FOR THE SNOW BELT AREAS. COLD FRONT HAS MOVED THROUGH THE AREA. SNOW WILL BE DEVELOPING THIS EVENING FROM NORTH TO SOUTH AS A SHORT WAVES MOVES IN. COULD BE A LITTLE JET HELP...SOME DIVERGENCE ALOFT OVER NORTHWEST OHIO LATE TONIGHT. THE NORTHEAST PORTION OF THE FORECAST AREA MAY GET A LITTLE LAKE ENHANCED SNOW...SO A LITTLE MORE SNOW. AN INCH OR LESS EXCEPT 1 TO 4 INCHES IN THE TRADITIONAL SNOW BELT. HOW MUCH OF A BREAK WILL OCCUR SUNDAY MORNING. SOME MOISTURE LINGERS BUT IT DOES TRY TO DRY OUT SOME ESPECIALLY IN NORTHEAST OHIO. IF THERE IS ENOUGH OF A BREAK IT WOULD BE ABLE TO BE PERCEIVED AS SEPARATE EVENTS. SOME MODEL DISCRIPENCIES...THE MESOSCALE DOESNT GIVE THAT MUCH TO GEAUGA AND INLAND ASHTABULA. BECAUSE OF THE BREAK IN ACTIVITY WILL GO WITH A LAKE EFFECT WATCH FOR THE TRADITIONAL SNOW BELT FROM NOON SUNDAY THROUGH 4 PM MONDAY. SOME QUESTION WITH THE MOISTURE AND WIND DIRECTION MONDAY...THE REASONING FOR KEEPING THE WATCH UNTIL 4 PM. MODELS IN GENERAL AGREEMENT WITH THE STRONG TROF MOVING THROUGH ON SUNDAY WITH ENOUGH MOISTURE...LIKELY POPS AGAIN. SOME DIFFERENCE IN THE LOCATION OF THE VORT AND THE AMOUNT OF SNOW. IT COULD BE MORE OF AN AFTERNOON AND EVENING FEATURE. GUIDANCE POPS MAY BE A LITTLE LOW...WILL GO 70%. THE MOISTURE FIELDS ARE A LITTLE CONFUSING THE 1000-700 ON THE NAM HAS IT INCREASING ACROSS THE AREA ALL DAY SUNDAY WHILE THE 1000-500 MB HOLDS BACK UNTIL THE TROF GETS CLOSER. AT THIS TIME WILL NOT PUT ANY RESOLUTION IN ON THE TIMING. WITH QUESTIONS WILL FORECAST 1 TO 2 INCHES EXCEPT A LITTLE MORE IN THE SNOW BELT. THE LOW POPS FROM THE MOS MAV SEEM WRONG. WILL CONTINUE THE SNOW FOR MAINLY EARLY SUNDAY NIGHT OUT IN THE WEST...THEN CHANCE POPS LATE. ON MONDAY A RIDGE TRIES TO BUILD IN SO THE LAKE EFFECT SNOW SHOWERS WILL TRY TO DECREASE. DRY NORTHWEST. ON MONDAY NIGHT MODELS IN GENERAL AGREEMENT WITH A TROF MOVING IN JUST SOME MOISTURE DIFFERENCE. WILL JUST GO WITH CHANCE POPS FOR THE TIME BEING. && .LONG TERM (TUESDAY-SATURDAY)... GFS/ECMWF/DIGEX ARE ALL IN GENERAL AGREEMENT IN MOVING THROUGH SYSTEMS FOR THE EXTENDED. SOME DIFFERENCES FOR SATURDAY. COLD FRONT AND LOW SHOULD BE EXITING THE FORECAST AREA TUESDAY MORNING. WITH HIGH MOISTURE...FORECASTING 50 POPS OR HIGHER EVERYWHERE IN THE FORECAST AREA AND LIKELY POPS IN THE SNOWBELT WITH A LAKE AND 850 MB TEMPERATURE DIFFERENCE NEAR 19C. S/WV MOVES THROUGH TUESDAY NIGHT AND THE FLOW IS FORECAST TO BE WESTERLY...THE BEST CHANCE WILL BE IN THE SNOWBELT IF THAT HOLD TRUE. HIGH PRESSURE TRIES TO BUILD IN FOR WEDNESDAY...A THREAT OF SNOW SHOWERS WILL CONTINUE MAINLY IN THE MORNING AS THE FLOW BECOMES SOUTHWEST. WITH TIMING ISSUES WILL NOT PUT ANY RESOLUTION IN BUT GO WITH CHANCE POPS. ANOTHER FRONTAL SYSTEM FOR LATE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. ALL MODELS IN AGREEMENT. CHANCE POPS AND CHANCE OF SNOW WEDNESDAY NIGHT THROUGH THURSDAY AS THE FLOW REMAINS SOUTHWEST. AS THE FLOW BECOMES WESTERLY THURSDAY NIGHT MAINLY SNOW SHOWERS IN THE LAKE EFFECT AREAS. WITH RIDGING FOR FRIDAY...JUST CHANCE POPS IN THE SNOW BELT. AS THE RIDGE SINKS SOUTH LAKE EFFECT OVER THE NORTHEAST COUNTIES. DIGEX AND GFS DIVERGE FOR SATURDAY. THE DIGEX BRINGS A LOW UP THE EAST COAST WHILE THE GFS PUSHED IN PLENTY OF COLD AIR WITH A LOT OF LAKE EFFECT. WITH SO MUCH COLD AIR BOTTLED UP...GOING WITH THE GFS SOLUTION FOR THE COLD AIR TO KEEP POURING IN SO PLENTY OF LAKE EFFECT. IF THE FLOW REMAINS WESTERLY AS FORECAST THE NORTHWEST PORTION OF THE FORECAST AREA WILL REMAIN GENERALLY DRY. COLDER AIR WILL CONTINUE TO FLOW IN FOR SATURDAY. CHANCE POPS FOR THE PRIMARY SNOWBELT AND SURROUNDING AREAS. WITH SOME QUESTIONS AS TO WHAT MODEL WILL BE RIGHT THE DIGEX IN MOVING THE LOW UP NEAR OHIO AND SINCE IT IS DAY 7 WILL BE CONSERVATIVE. NORTHWEST OHIO DRY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...LAKE EFFECT SNOW WATCH NOON SUNDAY THROUGH 4 PM MONDAY OHZ012>014-089 PA...LAKE EFFECT SNOW WATCH NOON SUNDAY THROUGH 4 PM MONDAY PAZ001>003 && $$ UPDATE...MRD SHORT TERM...KIELTYKA LONG TERM...KIELTYKA AVIATION...ADAMS