Thundersnow12 Posted February 17, 2011 Share Posted February 17, 2011 a very nice AFD from DVN MODERATE STRENGTH RAIN AND SNOW EVENT SUNDAY AND MONDAY IS THE FORECAST CHALLENGE... OVERVIEW...INITIALIZATION TODAY RANGES FROM ONLY FAIR TO VERY POOR RESULTING IN BELOW TO WELL BELOW AVERAGE CONFIDENCE ON NEXT SYSTEM. THERE ARE A SERIES OF ISSUES RANGING FROM MODEL POORLY HANDLING SNOW MELT (TOO SLOW) WITH TOO HIGH BL RH AND RADIATIVE TRANSFER ISSUES. THE PROBLEM IS ALL SOLUTIONS USE WHAT WE DESCRIBE AS PARAMETERIZED (ESTIMATED BEST FIT CURVES) PACKAGES. THEY ARE BASED ON AVERAGE WEATHER ELEMENT RELATIONSHIPS SO...LIKE A SEE SAW...WHEN A PARAMETER...LIKE SNOW...IS NOT HANDLED...IT CASCADES INTO OTHER AREAS. THIS IMPACTS THE MODEL HANDLING THE FUTURE AS OTHER END OF THE SEE SAW SWINGS WITH INCREASING ERRORS IN TIME LIKE A PERSON LEAVING ONE END OF THE SEE SAW THROWING THE OTHER PERSON AT THE OTHER END WILDLY INTO THE AIR. ADDING TO THIS IS ALL SOLUTIONS ARE POORLY HANDLING DIGGING ENERGY OFF CALIFORNIA WITH HI-RES ECMWF LEAST WORSE PER OPEN CUMULUS FIELDS. TRIED TO GO WITH A 60/40 BLEND OF HI-RES ECMWF AND GFS BUT LIMITED BY OFFICE COLLABORATION REQUIREMENTS. EXPECT MORE CHANGES WITH NEXT FORECAST CYCLE WITH AMOUNTS OF RAIN VERSUS SNOW AMOUNTS LIKELY STILL POORLY ADDRESSED AT THIS TIME. WE WILL EXPERIENCE SEASONAL LIGHT TO MAINLY MODERATE AMOUNTS...IT/S THE PRECIPITATION TYPE AND CHANGEOVER THAT IS A BIGGER ISSUE FOR MANY IF NOT MOST LOCATIONS. FRIDAY NIGHT THROUGH SUNDAY...AS DISCUSSED YESTERDAY...CONCERN ABOUT LEAD FORCING OF UPPER LEVEL ENERGY CONFIRMED AND HAVE UPPED POPS IN FORM OF RAIN. POORLY HANDLED FORCING FIELDS OF AMERICAN MODELS DO NOT SUGGEST CONVECTION ATTM AND EXPECT FURTHER FORECASTS WILL BE ABLE TO ADDRESS AND MARRY CONCEPTUALLY ANY UNLIKELY POTENTIAL RISK OF CONVECTION BY FRIDAY PM. MIN TEMPERATURES WITH INCREASING HIGH CLOUDS FRIDAY NIGHT MAY BE A CHALLENGE IF HIGH CLOUDS ARRIVE FASTER. MAIN FORCING APPEARS WILL ARRIVE LATE SATURDAY NIGHT INTO SUNDAY MORNING WITH SLIGHT RISK OF PATCHY FREEZING RAIN ALONG HIGHWAY 20...PROBLEM IS IF LOW LEVEL THERMAL FIELDS ARE ADEQUATELY HANDLED...ADDED QUESTIONABILITY WITH OUR RAPIDLY MELTING SNOW. LIGHT TO MODERATE RAINFALL AMOUNTS SUGGESTED INTO SUNDAY PM ATTM...MAINLY ALONG AND ESPECIALLY NORTH OF I-80. CLOUDS AND PRECIPITATION WILL LIKELY IMPACT HIGHS BY 5 PLUS DEGREES DUE TO EVAPORATIVE COOLING ISSUES. SUNDAY NIGHT AND MONDAY...KEPT CHANCE POPS DUE TO MAIN VORT MAX THAT WILL PASS WITH RAIN CHANGING TO SNOW. THIS IS THE VERY POOREST CONFIDENCE PORTION OF THE FORECAST WITH A FEW INCHES OF SNOW STILL POSSIBLE. SPREAD OF VARIANCE IN GUIDANCE IS EXCEPTIONALLY LARGE AND POOR INITIALIZATION INDICATES FURTHER CHANGES LIKELY NEXT 12 TO 18 HOURS WITH HOPEFULLY BETTER UPPER AIR SAMPLING TONIGHT AND AGAIN FRIDAY...YET ENERGY WILL NOT BE ONSHORE UNTIL SATURDAY. Link to comment Share on other sites More sharing options...
Harry Posted February 17, 2011 Share Posted February 17, 2011 a very nice AFD from DVN MODERATE STRENGTH RAIN AND SNOW EVENT SUNDAY AND MONDAY IS THE FORECAST CHALLENGE... OVERVIEW...INITIALIZATION TODAY RANGES FROM ONLY FAIR TO VERY POOR RESULTING IN BELOW TO WELL BELOW AVERAGE CONFIDENCE ON NEXT SYSTEM. THERE ARE A SERIES OF ISSUES RANGING FROM MODEL POORLY HANDLING SNOW MELT (TOO SLOW) WITH TOO HIGH BL RH AND RADIATIVE TRANSFER ISSUES. THE PROBLEM IS ALL SOLUTIONS USE WHAT WE DESCRIBE AS PARAMETERIZED (ESTIMATED BEST FIT CURVES) PACKAGES. THEY ARE BASED ON AVERAGE WEATHER ELEMENT RELATIONSHIPS SO...LIKE A SEE SAW...WHEN A PARAMETER...LIKE SNOW...IS NOT HANDLED...IT CASCADES INTO OTHER AREAS. THIS IMPACTS THE MODEL HANDLING THE FUTURE AS OTHER END OF THE SEE SAW SWINGS WITH INCREASING ERRORS IN TIME LIKE A PERSON LEAVING ONE END OF THE SEE SAW THROWING THE OTHER PERSON AT THE OTHER END WILDLY INTO THE AIR. ADDING TO THIS IS ALL SOLUTIONS ARE POORLY HANDLING DIGGING ENERGY OFF CALIFORNIA WITH HI-RES ECMWF LEAST WORSE PER OPEN CUMULUS FIELDS. TRIED TO GO WITH A 60/40 BLEND OF HI-RES ECMWF AND GFS BUT LIMITED BY OFFICE COLLABORATION REQUIREMENTS. EXPECT MORE CHANGES WITH NEXT FORECAST CYCLE WITH AMOUNTS OF RAIN VERSUS SNOW AMOUNTS LIKELY STILL POORLY ADDRESSED AT THIS TIME. WE WILL EXPERIENCE SEASONAL LIGHT TO MAINLY MODERATE AMOUNTS...IT/S THE PRECIPITATION TYPE AND CHANGEOVER THAT IS A BIGGER ISSUE FOR MANY IF NOT MOST LOCATIONS. FRIDAY NIGHT THROUGH SUNDAY...AS DISCUSSED YESTERDAY...CONCERN ABOUT LEAD FORCING OF UPPER LEVEL ENERGY CONFIRMED AND HAVE UPPED POPS IN FORM OF RAIN. POORLY HANDLED FORCING FIELDS OF AMERICAN MODELS DO NOT SUGGEST CONVECTION ATTM AND EXPECT FURTHER FORECASTS WILL BE ABLE TO ADDRESS AND MARRY CONCEPTUALLY ANY UNLIKELY POTENTIAL RISK OF CONVECTION BY FRIDAY PM. MIN TEMPERATURES WITH INCREASING HIGH CLOUDS FRIDAY NIGHT MAY BE A CHALLENGE IF HIGH CLOUDS ARRIVE FASTER. MAIN FORCING APPEARS WILL ARRIVE LATE SATURDAY NIGHT INTO SUNDAY MORNING WITH SLIGHT RISK OF PATCHY FREEZING RAIN ALONG HIGHWAY 20...PROBLEM IS IF LOW LEVEL THERMAL FIELDS ARE ADEQUATELY HANDLED...ADDED QUESTIONABILITY WITH OUR RAPIDLY MELTING SNOW. LIGHT TO MODERATE RAINFALL AMOUNTS SUGGESTED INTO SUNDAY PM ATTM...MAINLY ALONG AND ESPECIALLY NORTH OF I-80. CLOUDS AND PRECIPITATION WILL LIKELY IMPACT HIGHS BY 5 PLUS DEGREES DUE TO EVAPORATIVE COOLING ISSUES. SUNDAY NIGHT AND MONDAY...KEPT CHANCE POPS DUE TO MAIN VORT MAX THAT WILL PASS WITH RAIN CHANGING TO SNOW. THIS IS THE VERY POOREST CONFIDENCE PORTION OF THE FORECAST WITH A FEW INCHES OF SNOW STILL POSSIBLE. SPREAD OF VARIANCE IN GUIDANCE IS EXCEPTIONALLY LARGE AND POOR INITIALIZATION INDICATES FURTHER CHANGES LIKELY NEXT 12 TO 18 HOURS WITH HOPEFULLY BETTER UPPER AIR SAMPLING TONIGHT AND AGAIN FRIDAY...YET ENERGY WILL NOT BE ONSHORE UNTIL SATURDAY. Saturday? ugh.. Guess the models were off with that. Figured it would be onshore tomorrow afternoon. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 HPC model diagnostic disco. Mostly agree--and the northern vortex is truly the BIG if in my opinion. SREF's really want to push that feature eastward like the Euro--GFS/NAM are much slower. Down the middle right now is a perfectly good call even though I typically don't like to simply cut it in the middle. So much variance and still a threat for anything from a full blown cyclone to a strong frontal wave event. Having 2 and up to three moving parts with the amped baro zone makes this an extremely difficult forecast. Could be another 48+ hours until things get better sorted out where legitimate calls can be made. THE 12Z GEFS MEAN HAS TRENDED SOMEWHAT TOWARDTHE 12Z OPERATIONAL CLUSTERING. THE 12Z ECMWF STILL BECOMES QUITEPROGRESSIVE ALOFT ACROSS SRN CANADA WHILE HOLDING BACK NRN CONUSENERGY CLOSE TO THE 09Z SREF/06Z GEFS MEANS.GIVEN THE FULL ARRAY OF 12Z SOLNS NOW AVBL... ALONG WITH THETYPICAL DIFFICULTY THE MDLS CAN HAVE WITH HIGHER LATITUDE FLOW ANDDETAIL DIFFS THAT STILL EXIST WITH ENERGY MOVING THRU THE WEST...IT APPEARS TOO SOON TO TREND COMPLETELY TO THE GFS/NAM SCENARIO. HOWEVER WHAT ADJUSTMENTS THE 12Z ECMWF HAS MADE DO PROVIDEENCOURAGEMENT FOR A SOLN MORE NEAR THE MIDDLE OF THE SPREAD VERSUSTHE MORE SUPPRESSED ECMWF SFC SOLNS. IN PARTICULAR FINALPREFERENCES LEAN AWAY FROM THE STRENGTH OF THE GFS SFC SYSTEMDURING THE DAY SUN AS THE GFS IS STRONGER THAN OTHER SOLNSINCLUDING THE 12Z GEFS MEAN. A COMPROMISE AMONG THEUKMET/CANADIAN GLBL/ECMWF IS RECOMMENDED TO DEPICT THE DESIREDINTERMEDIATE SOLN... WITH A SWD ADJUSTED VERSION OF A NAM/GFSCOMPROMISE ALSO A FEASIBLE OPTION. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 a very nice AFD from DVN Snow pack is a big key issue too--and the lack of one may result in stronger WAA and enhancement of the low level baro zone as the warm air may track farther N and link up better with the polar air in Canada. That could have huge implications on intensity of the cyclone. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 18Z GFS through 42 looks like it is going to be coming in hot--hot as in intense. It is more consolidated out W with the trough and a tick faster with the upper vortex. Just analyzing as is--prolly a tick N and more intense than 12Z--that is my guess at this juncture. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 It is also slower. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted February 17, 2011 Share Posted February 17, 2011 Looks like a plastering of SN/PL/ZR Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 Well 18Z GFS took a step towards the Euro which is farther S--a little weaker--and slower. A lot more snow and less rain for many areas that were on the edge. Link to comment Share on other sites More sharing options...
Harry Posted February 17, 2011 Share Posted February 17, 2011 [/font] [/font]Snow pack is a big key issue too--and the lack of one may result in stronger WAA and enhancement of the low level baro zone as the warm air may track farther N and link up better with the polar air in Canada. That could have huge implications on intensity of the cyclone. In short it is a very tough call. Seems like everything is in these parts. On the one hand model have catch up to do with that while on the other they may be doing some catch up with the northern stuff/AO/NAO and such as well. Regardless of snowcover the stuff up north ( AO/NAO ) will dictate just how far north/nw this thing can come. Point of contention is where that is? Thus yeah it may be another 48hrs before we know. Typical nailbiter.. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 Parts of southern MN verbatim get 15+ of snow on this run. Prinsburg is jackpot. Link to comment Share on other sites More sharing options...
Moneyman Posted February 17, 2011 Share Posted February 17, 2011 GFS is a nice hit here. Looks like it trended toward the EURO a bit. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 In short it is a very tough call. Seems like everything is in these parts. On the one hand model have catch up to do with that while on the other they may be doing some catch up with the northern stuff/AO/NAO and such as well. Regardless of snowcover the stuff up north ( AO/NAO ) will dictate just how far north/nw this thing can come. Point of contention is where that is? Thus yeah it may be another 48hrs before we know. Typical nailbiter.. A definite nail-biter. This could very well be the most challenging high impact forecast of the winter. Link to comment Share on other sites More sharing options...
Moneyman Posted February 17, 2011 Share Posted February 17, 2011 GFS also has the 2nd low idea, it's farther SE and a bit weaker then the EURO though. 2nd low goes from ARK to TN so far through hr 105. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted February 17, 2011 Share Posted February 17, 2011 With the GFS now seeming to favor the first wave, it's amazing how quickly this storm is sneeking up on us. It's essentially a D3 event. Link to comment Share on other sites More sharing options...
goknights Posted February 17, 2011 Share Posted February 17, 2011 Frank better workout before sunday or else he is gonna hurt his back moving the cement in la crosse. Link to comment Share on other sites More sharing options...
Harry Posted February 17, 2011 Share Posted February 17, 2011 With the AO/NAO doing it's thing i personally don't mind being in this spot the GFS has it in. Would rather not be in the bullseye this far out and as well not on the northern edge either not the with AO/NAO doing what it looks to. That's me though.. Link to comment Share on other sites More sharing options...
SpartyOn Posted February 17, 2011 Share Posted February 17, 2011 A definite nail-biter. This could very well be the most challenging high impact forecast of the winter. We live for this though..gota love these systems. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted February 17, 2011 Share Posted February 17, 2011 My hunch, mostly from past experience, is that there's probably not going to be a lot of overlap between the best snows of the first wave and the best snows of the second wave. Link to comment Share on other sites More sharing options...
Madmaxweather Posted February 17, 2011 Share Posted February 17, 2011 are we discussing both waves in here? Wave 1 is rain and warm here Wave 2 is the interesting one..... Here is Buckeye land on 18z TUE 00Z 22-FEB 0.3 0.3 1011 92 89 0.04 552 543 TUE 06Z 22-FEB -3.8 -2.0 1008 97 96 0.42 547 540 Link to comment Share on other sites More sharing options...
Moneyman Posted February 17, 2011 Share Posted February 17, 2011 I think we should have seperate threads on the 2 storms imo. Link to comment Share on other sites More sharing options...
Madmaxweather Posted February 17, 2011 Share Posted February 17, 2011 I think we should have seperate threads on the 2 storms imo. I don't make threads just because the last one I made really ended busting for 99% of us.... Link to comment Share on other sites More sharing options...
patrick7032 Posted February 17, 2011 Share Posted February 17, 2011 A definite nail-biter. This could very well be the most challenging high impact forecast of the winter. I think in another 24 to 36 hours after the models ingest more upper air data things will slowly start to dare I say it "smooth out" some....one thing that is notable is the strength and amplitude of the short wave riding near 160W....it is this energy that will carve out a decent system next weekend....so I wonder if this system won't be a little more progressive which would agree with the more southern track. One thing that is nice is bufkit shows 100-200 cape above 850mb so maybe some of us will get a thunderstorm with it....could be my last one for a while........ Link to comment Share on other sites More sharing options...
Thundersnow12 Posted February 17, 2011 Share Posted February 17, 2011 A definite nail-biter. This could very well be the most challenging high impact forecast of the winter. besides chasing, thats what I live for, a tough winter forecast, up to my neck in data. Link to comment Share on other sites More sharing options...
dilly84 Posted February 17, 2011 Share Posted February 17, 2011 and the big storm the gfs was showing for Central OH basically gone. 27" on the 6z run to 4 or 5 on the 18z. Id rather have warmth. If it isnt gonna be a blockbuster I dont want it. Just my opinion. EDIT: NVM maps posted above are for the other storm. I will make on for the 22nd since I called it over a week ago. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 17, 2011 Share Posted February 17, 2011 Wow OT--but a gorgeous trapped wavetrain in the lee of the Coteau des Prairies/Buffalo Ridge behind the cold front. Link to comment Share on other sites More sharing options...
Madmaxweather Posted February 17, 2011 Share Posted February 17, 2011 and the big storm the gfs was showing for Central OH basically gone. 27" on the 6z run to 4 or 5 on the 18z. Id rather have warmth. If it isnt gonna be a blockbuster I dont want it. Just my opinion. EDIT: NVM maps posted above are for the other storm. I will make on for the 22nd since I called it over a week ago. Columbus gets a decent hit..... 18z TUE 00Z 22-FEB 0.3 0.3 1011 92 89 0.04 552 543 TUE 06Z 22-FEB -3.8 -2.0 1008 97 96 0.42 547 540 TUE 12Z 22-FEB -5.8 -6.8 1014 97 98 0.24 540 529 Link to comment Share on other sites More sharing options...
Madmaxweather Posted February 17, 2011 Share Posted February 17, 2011 FWIW 18z DGEX with wave 2 is a good hit for those north of I 70.... Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 17, 2011 Share Posted February 17, 2011 Parts of southern MN verbatim get 15+ of snow on this run. Prinsburg is jackpot. how bout winds, during or after the snowfall? Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 17, 2011 Author Share Posted February 17, 2011 It looks like both the MKX and ORD offices are doing a pretty poor job in regards to wave number 2. MKX doesn't even mention it, giving a pretty small chance of precip Monday afternoon and evening, when the second wave is likely to come through. ORD has a slight chance of snow on Monday, so even less respect. What am I missing? On the MKE soundings off the Euro, it showed a little over 0.6 QPF falling late Monday, so that should at least be factored into the equation. Link to comment Share on other sites More sharing options...
snowstormcanuck Posted February 17, 2011 Share Posted February 17, 2011 It looks like both the MKX and ORD offices are doing a pretty poor job in regards to wave number 2. MKX doesn't even mention it, giving a pretty small chance of precip Monday afternoon and evening, when the second wave is likely to come through. ORD has a slight chance of snow on Monday, so even less respect. What am I missing? On the MKE soundings off the Euro, it showed a little over 0.6 QPF falling late Monday, so that should at least be factored into the equation. I think the EURO is the only one as far north as that with the second wave, so they're not giving it too much weight it seems. Link to comment Share on other sites More sharing options...
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