Cary67 Posted January 9, 2020 Share Posted January 9, 2020 12 minutes ago, ILSNOW said: Need a shift SE of 40 miles 1 Link to comment Share on other sites More sharing options...
Hoosier Posted January 9, 2020 Share Posted January 9, 2020 The GFS and Euro surface low tracks are practically identical, but there are notable differences in the sfc/near sfc temps. Would love to get RC's take on the sfc temps. 4 Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 9, 2020 Share Posted January 9, 2020 I assume that max precip band is more NW on the Euro vs the GFS? as in directly over me instead of me being on the NW edge? Link to comment Share on other sites More sharing options...
nwohweather Posted January 9, 2020 Share Posted January 9, 2020 4 minutes ago, Moosey2323 said: I think the general rule of thumb is to underestimate the northward extent of the warm front, especially in situations with convection to the south. The Euro/Canadian seems to place the warm front too far north. I think the NAM 3km is the better solution. Disagree entirely with so much gulf moisture being pumped into this thing. Unless you believe the LLJ is being overdone, I see no reason to believe that a warm bias would be occurring. I believe the bias you are mentioning has been a warm season bias, not a winter bias. And even then that is because soil moisture affects results Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 9, 2020 Share Posted January 9, 2020 for the River level forecasts: Do you happen to know if they used 48 hour rainfall (12z today thru 12z Sat) or used the full 3 days on the WPC forecast (another inch or so after 12z Sat) it is obviously not just the next 24 hours like it says in the wording Have family members that get isolated when the river hits 25.8 at PIA crest 23.4 just issued right now it looks like the SE part of the IL river basin gets 4 inches(with that much also falling south of the basin.. the rest 1-3... of course a shift in the heavy band will affect the levels I think they're using 48 hours but I could be wrong on that. Sent from my SM-G965U using Tapatalk Link to comment Share on other sites More sharing options...
purduewx80 Posted January 9, 2020 Share Posted January 9, 2020 10 minutes ago, Moosey2323 said: I think the general rule of thumb is to underestimate the northward extent of the warm front, especially in situations with convection to the south. The Euro/Canadian seems to place the warm front too far north. I think the NAM 3km is the better solution. Alternatively, this is the kind of convective outbreak that will pump the SE ridge enough to allow the warm air aloft to overspread surface cooling. That's why we're seeing a band of sleet and freezing rain. 2 Link to comment Share on other sites More sharing options...
DAFF Posted January 9, 2020 Share Posted January 9, 2020 1 hour ago, Hoosier said: Small differences affecting very populated areas I wonder how much of the 2M air temp differences shown are from the interpretation of the modeling pools of warmth from the lakes. The NAM seems much more sensitive to the warm waters over the GFS. Link to comment Share on other sites More sharing options...
WestMichigan Posted January 9, 2020 Share Posted January 9, 2020 17 minutes ago, nwburbschaser said: I'm probably 30 miles from a sig snow event so I'm really hoping that this can come a bit south. Hopefully convection can do the trick and put N IL into the snow although I have doubts it will happen. Several runs in a row go from 8-9" on the north side of my county to DAB-1". I don't even need 30 miles. Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 9, 2020 Share Posted January 9, 2020 The GFS and Euro surface low tracks are practically identical, but there are notable differences in the sfc/near sfc temps. Would love to get RC's take on the sfc temps. Maybe it's to the point where the GFS is overcompensating for the effects of the high pressure to the north? That's a bit of a wild card. I do think with the angle of approach of the surface low, it will favor areas west of the lake staying below freezing because you don't lose the northerly component to the wind and that's pulling from very cold and dry air to the north. That said, GFS seems too cold. The ECMWF tends to do pretty well with temps so would have to lean towards what it's showing with the tracks being very similar. It'll be an interesting test case for the new version of the GFS. Sent from my SM-G965U using Tapatalk 1 2 Link to comment Share on other sites More sharing options...
Hoosier Posted January 9, 2020 Share Posted January 9, 2020 12 minutes ago, DAFF said: I wonder how much of the 2M air temp differences shown are from the interpretation of the modeling pools of warmth from the lakes. The NAM seems much more sensitive to the warm waters over the GFS. Maybe. I remember dropping to like 31 for a while in the 12/28/15 event. I'm going to assume lake temps were similar back then (later in the season now but we are coming off a very warm period) but who knows, maybe the cold layer was better back then or the wind direction was subtly different. Link to comment Share on other sites More sharing options...
Chinook Posted January 9, 2020 Share Posted January 9, 2020 This is the NWS forecast for the next 66 hours. I'm sure they will be basing their winter storm watches and winter storm warnings on this or something similar. The Weatherbell web site also has a graphic for the freezing rain expected, but it's confusing right now, but it says 0.48" of freezing rain for Grand Rapids, MI. Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 9, 2020 Share Posted January 9, 2020 This sounding over northern IL from the 12z Euro illustrates the point I've made about the model ptype algorithm potentially overforecasting freezing rain and underforecasting sleet. In the lower right of the pivotalwx soundings, they have temperature and wet bulb profile information. The positive and negative energies in J/kg are from the Bourgoin layer energy ptype technique. When there is a warm layer aloft sufficient for full melting, whether ptype is sleet or freezing rain depends on the negative energy below it. Two of my co-workers have done extensive work on modifying the Bourgoin method based off observed soundings and ptype observations from the events used and they're getting a paper published in AMS. Many of the NWS offices in the area use this method for ptype derivation. In it, the studies done show that when negative energies get greater than -100 J/kg, sleet probs steadily increase and -125 J/kg or more is 100% sleet probs with lower freezing rain probs even if there is more positive energy aloft. Based off the wet bulb profile showing -156 I think that sounding would support sleet more than freezing rain even though best guess precip type is listed as freezing rain. Sent from my SM-G965U using Tapatalk 11 1 Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 9, 2020 Share Posted January 9, 2020 doing good posts ricky 4 Link to comment Share on other sites More sharing options...
Hoosier Posted January 9, 2020 Share Posted January 9, 2020 8 minutes ago, RCNYILWX said: This sounding over northern IL from the 12z Euro illustrates the point I've made about the model ptype algorithm potentially overforecasting freezing rain and underforecasting sleet. In the lower right of the pivotalwx soundings, they have temperature and wet bulb profile information. The positive and negative energies in J/kg are from the Bourgoin layer energy ptype technique. When there is a warm layer aloft sufficient for full melting, whether ptype is sleet or freezing rain depends on the negative energy below it. Two of my co-workers have done extensive work on modifying the Bourgoin method based off observed soundings and ptype observations from the events used and they're getting a paper published in AMS. Many of the NWS offices in the area use this method for ptype derivation. In it, the studies done show that when negative energies get greater than -100 J/kg, sleet probs steadily increase and -125 J/kg or more is 100% sleet probs with lower freezing rain probs even if there is more positive energy aloft. Based off the wet bulb profile showing -156 I think that sounding would support sleet more than freezing rain even though best guess precip type is listed as freezing rain. Sent from my SM-G965U using Tapatalk Good stuff. Looks like southwest of Streamwood? The southern part of the modeled freezing rain area seems like a better bet for less sleet, but sfc temps would be more marginal. 1 Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 9, 2020 Share Posted January 9, 2020 hope joe's palm box holds up 1 Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 9, 2020 Share Posted January 9, 2020 1 minute ago, A-L-E-K said: hope joe's palm box holds up It's a fortress. 3 Link to comment Share on other sites More sharing options...
wisconsinwx Posted January 9, 2020 Share Posted January 9, 2020 3 minutes ago, A-L-E-K said: hope joe's palm box holds up The one he borrowed from Tropical? That was the snow magnet palm box. 2 Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 9, 2020 Share Posted January 9, 2020 1 hour ago, Thundersnow12 said: We get you gotta ride that call into the ground but it's clearly not lol Link to comment Share on other sites More sharing options...
RCNYILWX Posted January 9, 2020 Share Posted January 9, 2020 Good stuff. Looks like southwest of Streamwood? The southern part of the modeled freezing rain area seems like a better bet for less sleet, but sfc temps would be more marginal.Agree there I've been thinking farther south in the area showing freezing rain. Would think with westward extent too where you have a higher chance of staying below freezing deeper into the cold air. This is all obviously dependent on the exact sfc low track which we haven't completely nailed down yet. Bringing up the 2015 event again, what I found really impressive with it is that the mesoanalysis at the time and reanalysis indicated that the 850 mb temps south of I-80 got as high as +8 to +10 but yet that's where the most significant ice accums were in the CWA. Sent from my SM-G965U using Tapatalk 2 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 9, 2020 Author Share Posted January 9, 2020 1 minute ago, A-L-E-K said: P sure that’s the plumes. Not the euro which you said was a rainer. Even got Joe to laugh about that one 1 Link to comment Share on other sites More sharing options...
Hoosier Posted January 9, 2020 Share Posted January 9, 2020 Cooler by the lake season (On that note, the GEM frontal position tomorrow is laughable) 1 2 Link to comment Share on other sites More sharing options...
nwohweather Posted January 9, 2020 Share Posted January 9, 2020 41 minutes ago, RCNYILWX said: This sounding over northern IL from the 12z Euro illustrates the point I've made about the model ptype algorithm potentially overforecasting freezing rain and underforecasting sleet. In the lower right of the pivotalwx soundings, they have temperature and wet bulb profile information. The positive and negative energies in J/kg are from the Bourgoin layer energy ptype technique. When there is a warm layer aloft sufficient for full melting, whether ptype is sleet or freezing rain depends on the negative energy below it. Two of my co-workers have done extensive work on modifying the Bourgoin method based off observed soundings and ptype observations from the events used and they're getting a paper published in AMS. Many of the NWS offices in the area use this method for ptype derivation. In it, the studies done show that when negative energies get greater than -100 J/kg, sleet probs steadily increase and -125 J/kg or more is 100% sleet probs with lower freezing rain probs even if there is more positive energy aloft. Based off the wet bulb profile showing -156 I think that sounding would support sleet more than freezing rain even though best guess precip type is listed as freezing rain. Sent from my SM-G965U using Tapatalk You'll know more than I about this but doesn't heavy rain give off quite a bit of latent heat which would then help it turn into a higher percentage of sleet falling as opposed to strictly freezing rain? Link to comment Share on other sites More sharing options...
wegoweather Posted January 9, 2020 Share Posted January 9, 2020 Winter Storm Watch on top of a Flood Watch for parts of LOT. Quote Winter Storm Watch URGENT - WINTER WEATHER MESSAGE National Weather Service Chicago IL 136 PM CST Thu Jan 9 2020 ...Significant Snow and Ice Accumulations Possible late Friday Night Through Saturday Night... ILZ006-012-013-019-020-100345- /O.NEW.KLOT.WS.A.0001.200111T0600Z-200112T0900Z/ Lake IL-Kane-DuPage-La Salle-Kendall- Including the cities of Waukegan, Buffalo Grove, North Chicago, Highland Park, Mundelein, Gurnee, Round Lake Beach, Aurora, Elgin, Naperville, Wheaton, Downers Grove, Elmhurst, Lombard, Carol Stream, Addison, Ottawa, Streator, Peru, La Salle, Mendota, Marseilles, Oswego, Boulder Hill, Yorkville, and Plano 136 PM CST Thu Jan 9 2020 ...WINTER STORM WATCH IN EFFECT FROM LATE FRIDAY NIGHT THROUGH LATE SATURDAY NIGHT... * WHAT...A mix of freezing rain and sleet likely late Friday night and Saturday, possibly changing to a period of snow Saturday evening. Total ice and sleet accumulations in excess of a quarter inch are possible late Friday night into Saturday. Total snow accumulations in excess of 3 inches are also possible Saturday evening. Winds could gust as high as 40 mph Friday night and Saturday. * WHERE...Lake IL, Kane, DuPage, La Salle and Kendall Counties. * WHEN...From late Friday night through late Saturday night. * IMPACTS...Power outages and tree damage are possible due to the ice and windy conditions. Travel could be significantly impacted across the area Friday night through Saturday evening. PRECAUTIONARY/PREPAREDNESS ACTIONS... Monitor the latest forecasts for updates on this situation. && $$ 4 Link to comment Share on other sites More sharing options...
Sciascia Posted January 9, 2020 Share Posted January 9, 2020 3 minutes ago, wegoweather said: Winter Storm Watch on top of a Flood Watch for LOT. Probably obvious, but just passing along the note that the WSW for the more NW counties (Winnebago, Boone (mby), DeKalb, McHenry, Ogle, Lee) is different than the one for Cook, in terms of snow/ice amounts. Link to comment Share on other sites More sharing options...
wegoweather Posted January 9, 2020 Share Posted January 9, 2020 1 minute ago, Sciascia said: Probably obvious, but just passing along the note that the WSW for the more NW counties (Winnebago, Boone (mby), DeKalb, McHenry, Ogle, Lee) is different than the one for Cook, in terms of snow/ice amounts. Correct. Multiple Watches issued with varying frozen/snow accum possibilities. . 1 Link to comment Share on other sites More sharing options...
Malacka11 Posted January 9, 2020 Share Posted January 9, 2020 Rolling out the 18z suite. The reckoning is at hand my boys. 2 2 Link to comment Share on other sites More sharing options...
Geoboy645 Posted January 9, 2020 Share Posted January 9, 2020 I am going to say that thank god there isn't a snowpack right now over southern Illinois and Indiana. Otherwise we'd have a repeat of Nebraska last year. Link to comment Share on other sites More sharing options...
Baum Posted January 9, 2020 Share Posted January 9, 2020 11 minutes ago, Malacka11 said: Rolling out the 18z suite. The reckoning is at hand my boys. The reckoning will be when you look out your window about 11 am Saturday..... 1 1 Link to comment Share on other sites More sharing options...
madwx Posted January 9, 2020 Share Posted January 9, 2020 NAM going big league in IA/S WI with the first wave, 4-5" + 1 Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted January 9, 2020 Share Posted January 9, 2020 Shame that multi-zone for Cook isn't active till March. Would be a perfect storm set up to utilize it. 1 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now