Hoosier Posted February 9, 2018 Share Posted February 9, 2018 3 minutes ago, StormChaser4Life said: Anyone noticing some thermal profile issues on nam and hrrr? They both are showing rain/mixed precip developing south of the snow band tmrw morning. Not sure if I buy that unless models are under estimating surface temps but with some snow pack I think it should stay under 32 Can't rule out some mix, but I think the higher probability scenario is a transition toward a wetter snow on the southern edge tomorrow. Link to comment Share on other sites More sharing options...
Radtechwxman Posted February 9, 2018 Share Posted February 9, 2018 Mix is def possible. Esp with the intense WAA aloft. But rain I'm thinking no. Ha. 0z nam fizzles out the main band from tonight and redevelops a second one further south as that boundary sags south Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted February 9, 2018 Share Posted February 9, 2018 1 hour ago, snowstormcanuck said: Last few frames of the HRRR are showing the LES potential. Maybe our saving grace as it's becoming patently clear the best synoptic snow for wave one will be well south of us. I'm not overly optimistic about wave one on Friday. It's waves 2 and 3 (Saturday and especially Sunday) that I'm hoping will deliver. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted February 9, 2018 Share Posted February 9, 2018 1 hour ago, Snowstorms said: The secondary and third wave punch the Nam, CMC and EURO advertise is key. Good moisture and baroclinic energy to work with to allow for some deformation bands to form and for the storm to strengthen as it moves north. I'd watch it closely, it might hopefully deliver. As I said to canuck, this is what I'm hoping for too. Regardless, looks to be an interesting weekend weatherwise! Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 9, 2018 Share Posted February 9, 2018 15 minutes ago, Baum said: Just watch the radar at this point......and out your window. Yep. Now casting time Link to comment Share on other sites More sharing options...
GreenBo Posted February 9, 2018 Share Posted February 9, 2018 1 hour ago, snowstormcanuck said: HRRR also showing kind of a squall line in SE MI that is reminiscent of the February 20th, 2011 storm. Wyandotte is going to rock. That was a fun storm. Looks like the potential is there for some booms again. HRRR unloadss on the Detroit area. Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2018 Share Posted February 9, 2018 Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 813 PM CST Thu Feb 8 2018 .UPDATE... 813 PM CST No big changes planned to the overall forecast for the storm, however, will likely move up the end time of the warning Friday as the brunt of the snow will likely have fallen by mid-late morning Friday in the warning. Regional radar composite shows a long band of mostly light to moderate snow extending from northern IL WNW into SD. A short wave trough over the Dakotas early this evening shows up fairly well on GOES-16 differential water vapor RGB. This shortwave is forecast to shear quickly into the western Great Lakes Friday morning, shearing out/weakening as it translates eastward. Primarily light-moderate snow will continue this evening as thermally direct circulation in the right entrance region of 120kt+ 250mb jet supports continued low-mid level frontogenesis over about the northern 2/3rds of the CWA. As the Dakota`s shortwave translates eastward, guidance suggests a strengthening of the lower level f-gen and a resultant uptick in the UVVs over northern IL. Forecast vertical cross sections through the frontal band are a bit worrisome for our double digit snowfall forecast amounts. The last several runs of the RAP and 18z run of the NAM show virtually no negative saturated EPV, which indicates that the atmosphere is progged to be relatively stable and not primed for narrow intense banded snow. In addition, guidance suggests that areas of stronger f-gen will be somewhat transient in nature. While these factors are concerning, short range high-res guidance continues to advertise very beefy QPF values overnight into at least the first part of Friday morning, so not planning any changes to our forecast snowfall totals at this point. There has been a pretty consistent signal across the spectrum of model guidance suggesting that the meaningful snowfall will shift mainly south of the winter storm warning area between 12-18z Friday as shearing out shortwave passes east and associated height falls nudge the upper jet and associated entrance region a bit farther south. Given the expectation that snowfall across much of the warning area will waning prior to 18z, think that for messaging purposes an earlier end time to the warning is justifiable. Latest guidance suggests that additional snowfall accumulations beyond late morning would be somewhat trivial where the warning is in effect. Working on some fine tuning to grids and will have an updated WSW and grids/derived products out shortly. - Izzi Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2018 Share Posted February 9, 2018 Nice (narrow) band headed toward Tim in Kankakee. Link to comment Share on other sites More sharing options...
Snowstorms Posted February 9, 2018 Author Share Posted February 9, 2018 6 minutes ago, Ottawa Blizzard said: As I said to canuck, this is what I'm hoping for too. Regardless, looks to be an interesting weekend weatherwise! The cut-off with this system is just brutal. The difference 25 miles makes is remarkable. Link to comment Share on other sites More sharing options...
mimillman Posted February 9, 2018 Share Posted February 9, 2018 NAM keeps it going after a pause Friday evening, a couple more inches Saturday Link to comment Share on other sites More sharing options...
Baum Posted February 9, 2018 Share Posted February 9, 2018 Izzi trying to subtly walk back some of the higher amounts put out by LOT earlier in the day with a recent update. Not surprising........ Link to comment Share on other sites More sharing options...
beavis1729 Posted February 9, 2018 Share Posted February 9, 2018 Wow, LOT is already in downgrade mode...not a good sign. Link to comment Share on other sites More sharing options...
TugHillMatt Posted February 9, 2018 Share Posted February 9, 2018 Is the HRRR the model to follow this close in? It has been bumping up snowfall totals farther north in Michigan. Even has me getting over 7 inches. Link to comment Share on other sites More sharing options...
beavis1729 Posted February 9, 2018 Share Posted February 9, 2018 1 minute ago, Baum said: Izzi trying to subtly walk back some of the higher amounts put out by LOT earlier in the day with a recent update. Not surprising........ I actually think it is surprising. There were several models showing at least 0.8” liquid, which means 12” at 15:1 ratios. Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2018 Share Posted February 9, 2018 1 minute ago, beavis1729 said: I actually think it is surprising. There were several models showing at least 0.8” liquid, which means 12” at 15:1 ratios. I'm not seeing a reason for panic yet. Maybe the amounts over a foot are a little optimistic for tonight/tomorrow, but I think the double digit totals are still plausible. Link to comment Share on other sites More sharing options...
mimillman Posted February 9, 2018 Share Posted February 9, 2018 3 minutes ago, beavis1729 said: I actually think it is surprising. There were several models showing at least 0.8” liquid, which means 12” at 15:1 ratios. It’s not surprising. It’s a different meteorologist, different views, different biases. I think Izzi is right to lower totals personally. Link to comment Share on other sites More sharing options...
hlcater Posted February 9, 2018 Share Posted February 9, 2018 1 minute ago, Hoosier said: I'm not seeing a reason for panic yet. Maybe the amounts over a foot are a little optimistic for tonight/tomorrow, but I think the double digit totals are still plausible. On a different note, I am 100% expecting double digit totals in north Linn county, hwy-20 under the fgen band. 35 dbz, likely big flakes and thus high ratios. Interested to see what totals we can pull out of Waterloo, independence and coggon. Link to comment Share on other sites More sharing options...
Chicago WX Posted February 9, 2018 Share Posted February 9, 2018 9 minutes ago, Hoosier said: Nice (narrow) band headed toward Tim in Kankakee. It’s actually snowed pretty decently here tonight. Considering no guidance had this, I’ll take it as a gift, haha. Over soon though. And the 0z NAM’s take all of Saturday’s action to the north of here too, so this is probably it for me, lol. Good luck the rest of the way man. Hope it overachieves. Link to comment Share on other sites More sharing options...
indeedinger Posted February 9, 2018 Share Posted February 9, 2018 2 minutes ago, NWLinnCountyIA said: On a different note, I am 100% expecting double digit totals in north Linn county, hwy-20 under the fgen band. 35 dbz, likely big flakes and thus high ratios. Interested to see what totals we can pull out of Waterloo, independence and coggon. I will let you know . . . Link to comment Share on other sites More sharing options...
Baum Posted February 9, 2018 Share Posted February 9, 2018 8 minutes ago, mimillman said: It’s not surprising. It’s a different meteorologist, different views, different biases. I think Izzi is right to lower totals personally. Particularly with that met. Shaved timing of warning expiration from 9pm Friday until Noon. So in less than 5 hrs time that decision is made at the onset of an event? Just odd. Link to comment Share on other sites More sharing options...
DAWGNKITTEN Posted February 9, 2018 Share Posted February 9, 2018 I tried getting the HRRR up, but cannot understand how it really works. There were like 9 pictures, which is the ensemble maybe? Like I said, have no clue. And trying to tell a disabked vet that were gonna get 2-4 or 7-8 is funny because he knows I love weather, but he thinks I should KNOW how to read the maps. This winter every single time they said and inch or two we ended up with 6-8, so he thinks it will be like that. Just at a loss. Link to comment Share on other sites More sharing options...
Malacka11 Posted February 9, 2018 Share Posted February 9, 2018 2 minutes ago, Baum said: Particularly with that met. You know, I've never considered that different meteorologists have different opinions of the same event like that. Link to comment Share on other sites More sharing options...
McDude Posted February 9, 2018 Share Posted February 9, 2018 1 hour ago, McDude said: Alright, much better now. And back to caca sugar flakes Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2018 Share Posted February 9, 2018 2 minutes ago, Chicago WX said: It’s actually snowed pretty decently here tonight. Considering no guidance had this, I’ll take it as a gift, haha. Over soon though. And the 0z NAM’s take all of Saturday’s action to the north of here too, so this is probably it for me, lol. Good luck the rest of the way man. Hope it overachieves. Somebody should've told the NAM about your precip. May be a long haul but I think even you could grind out several inches by the time this is all over Link to comment Share on other sites More sharing options...
mimillman Posted February 9, 2018 Share Posted February 9, 2018 1 minute ago, Malacka11 said: You know, I've never considered that different meteorologists have different opinions of the same event like that. There’s an art to the science. As scientific and well documented as the subject is, it’s still highly interpretive. Link to comment Share on other sites More sharing options...
Snowstorms Posted February 9, 2018 Author Share Posted February 9, 2018 The H5 differences past 54 hrs between the 0z and 18z Nam is just terrible. Upper air instability would be favorable for partial phasing and good development on the north side of the system which I think will be more properly handled through tomorrow's runs. The spinning energy across Hudson Bay, which is actually a part of the PV, plays a key role in the development of the secondary wave. I could be wrong but let's see! Link to comment Share on other sites More sharing options...
Natester Posted February 9, 2018 Share Posted February 9, 2018 The cutoff line is only a couple miles south of me. :axe:. Looks like it's going to be either very light snow or no snow for several hours. I highly doubt we'll reach 5 inches from wave 1. The 0z NAM does show potential for here from wave 2 late tomorrow. Link to comment Share on other sites More sharing options...
beavis1729 Posted February 9, 2018 Share Posted February 9, 2018 Ok, I need to clarify. I am talking about double digit totals for both waves for Chicago metro, not just wave 1. Agree that double digits with just wave 1 is not likely in all areas. However, if anyone in the 6-county metro area ends up with under 10” by the end of the weekend, it will be a disappointment. Link to comment Share on other sites More sharing options...
Stebo Posted February 9, 2018 Share Posted February 9, 2018 1 minute ago, Snowstorms said: The H5 differences past 54 hrs between the 0z and 18z Nam is just terrible. Upper air instability would be favorable for partial phasing and good development on the north side of the system which I think will be more properly handled through tomorrow's runs. The spinning energy across Hudson Bay, which is actually a part of the PV, plays a key role in the development of the secondary wave. I could be wrong but let's see! Agree, the energy moving in from the west is slower stronger and less flat this run. Link to comment Share on other sites More sharing options...
ConvectiveIA Posted February 9, 2018 Share Posted February 9, 2018 Early, and I mean very early, evidence of southward sag of the main band to our west. It, and the NWS forecasts are all the hope I have. And I'm normally not one to severely question their forecasts except this time where those model runs are so out of agreement with the forecast. Link to comment Share on other sites More sharing options...
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