mimillman Posted February 9, 2020 Share Posted February 9, 2020 SN- Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2020 Share Posted February 9, 2020 This would be fairly lengthy for an afternoon or overnight afd let alone an "update." Nice job LOT. Area Forecast Discussion...UPDATED National Weather Service Chicago/Romeoville, IL 1110 AM CST Sun Feb 9 2020 .UPDATE... 1110 AM CST The general theme of this afternoon`s forecast continues with moderate snow expanding across the area and peaking through 2 pm. True heavy snow rates, while much more transient than continuous in a lot of the CWA, will bring very low visibility and quick snow- covered roads. As expected low-level warming has inched surface temperatures upward to 32-34 in advance of the snow in northeast Illinois and northwest Indiana, so areas where the rate is not heavy or very short-lived heavy, impacts on treated roads may be pretty limited. No changes to the ongoing Advisory. We should be able to end some western and southern areas before expiration. The regional mosaic looks more of March than the first half of February, with a semi-convective presentation across central and southern Illinois and Indiana, and more stratified precipitation across far northern Illinois into Wisconsin. The southern area is associated with a sheared mid-level short wave and associated 65 kt 500 mb speed maximum entering far western Illinois, and equally attributed to the robust low-level jet/moisture transport in place. This low-level jet presently is observed at 70 kt at 850 mb on the St Louis 88D and TDWR. Not surprising that this rapid warm advection source has steepened lapse rates and resulted in convective behavior in central Illinois, and this area will move across the southeast third of the CWA or so (south of a Streator IL to Gary IN line). There likely will be some pockets of mixed precipitation with this, including ice pellets/very small hail based on upstream mPing reports. Any snow within this area should be very transient given the warm nose aloft and warming low-level temperatures, but any snow could come down quite heavy for short spurts given the rich wintertime moisture, instability, and precipitation rate- driven wet-bulb cooling all indicated on the 12Z ILX sounding. Further north, the snow is being driven more directly by the short wave`s forcing as well as the stronger wave`s forcing and warm advection zone of lift. For far northern Illinois (north of I-88) this is still expected to be where the longest duration snow is and better thermal profiles to support average ratios as opposed to the wetter much lower ones south. Observations have shown 1/2 to 1 mile visibility in that far northern area or immediately upstream, and Rockford area webcams have shown quick deterioration between 1030 and 11 am. This remains the most favored area for isolated totals of three inches or a little higher. For in-between...basically I-80 to I-88...there likely has been some moisture robbing from the activity to the south and narrowing the window of time for the appreciable snow. Visibility in this area has not been particularly low in snow thus far, and webcams have indicated snow struggling to stick on at least main roads. The RAP and HRRR this morning have indicated this area receiving less QPF, with sort of a bimodal QPF presentation in the CWA and observational trends are showing reflection of this. Difficult to say if this will extend into the Chicago area which also has some of the milder surface air temperatures (33-35), but either way there will be a period of moderate snow with gusty winds so at least some temporary low visibility and some hazardous travel expected through 2 pm. Again snowfall amounts are really difficult to say in this semi-convective situation, especially south of I-88, with just a slight amount in some places to a quick couple inches in others. The message continues to focus on the short period of very low visibility and hazardous travel. The snow ending/transition to drizzle time from 1-2 pm west to 2-4 pm east looks good, with the entire far north (near WI state line) likely to hang onto impacting snow through mid afternoon. Intensity on this should be diminishing though after 2-3 pm. MTF Link to comment Share on other sites More sharing options...
mimillman Posted February 9, 2020 Share Posted February 9, 2020 5 minutes ago, mimillman said: SN- Quickly transitioned to SN Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 9, 2020 Share Posted February 9, 2020 Insta rip 1 Link to comment Share on other sites More sharing options...
Baum Posted February 9, 2020 Share Posted February 9, 2020 Decent rates. Quick ground cover. Looks like it will play out as called. Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2020 Share Posted February 9, 2020 Snow underway here too. 1 Link to comment Share on other sites More sharing options...
Snowstorms Posted February 9, 2020 Share Posted February 9, 2020 HRRR, RGEM and NAM all have ~2-3" for the GTA. It'll likely be closer to 2" near the lake. It'll be a quick hitting clipper. Could see 0.5"-1"/hr rates across the GTA. Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2020 Share Posted February 9, 2020 Rates definitely picked up quickly. Sideways snow. Band of 30+ dbz looks well positioned to train here for a while. Link to comment Share on other sites More sharing options...
mimillman Posted February 9, 2020 Share Posted February 9, 2020 Great rates and good sized dendrites. Unfortunately nothing really sticking in the city. The ground is too warm Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 9, 2020 Share Posted February 9, 2020 Have been getting solid periods of SN, probably borderline +SN at times.Solid DAB so far.. Link to comment Share on other sites More sharing options...
Chambana Posted February 9, 2020 Share Posted February 9, 2020 Had a period of slop, but temps have warmed to 35 degrees and all rain here. Warming to about 40 degrees, probably wiping out the “snowpack” we had. We’ve struggled keeping any snow on the ground this winter. 1 Link to comment Share on other sites More sharing options...
King James Posted February 9, 2020 Share Posted February 9, 2020 Big ol flakes . Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2020 Share Posted February 9, 2020 4 minutes ago, King James said: Big ol flakes . Curious when you will change over because I won't be far behind. Link to comment Share on other sites More sharing options...
Baum Posted February 9, 2020 Share Posted February 9, 2020 coming down nicely again...wind has been a non factor. Link to comment Share on other sites More sharing options...
vortex Posted February 9, 2020 Share Posted February 9, 2020 42 minutes ago, Hoosier said: Rates definitely picked up quickly. Sideways snow. Band of 30+ dbz looks well positioned to train here for a while. Mostly sleet and rain here, with some flakes thrown in. Link to comment Share on other sites More sharing options...
cyclone77 Posted February 9, 2020 Share Posted February 9, 2020 9.9" up at La Crosse. Pretty impressive. Finished with a few tenths of rain (some very minor glazing), and 0.1" of sleet. Link to comment Share on other sites More sharing options...
King James Posted February 9, 2020 Share Posted February 9, 2020 Curious when you will change over because I won't be far behind. Changing over now. Pinging off the window and I can see the water tower again Link to comment Share on other sites More sharing options...
Baum Posted February 9, 2020 Share Posted February 9, 2020 legit heavy snow.... 3 Link to comment Share on other sites More sharing options...
sbnwx85 Posted February 9, 2020 Share Posted February 9, 2020 Flakes starting here. Temp on the thermometer at 33. -SN Link to comment Share on other sites More sharing options...
Mogget Posted February 9, 2020 Share Posted February 9, 2020 About five inches of snow on the road and one truck on the lawn. Nice storm! Link to comment Share on other sites More sharing options...
Hoosier Posted February 9, 2020 Share Posted February 9, 2020 Last hurrah coming through now. Degree or two colder would've helped as accumulation efficiency was hampered a bit. Link to comment Share on other sites More sharing options...
Jackstraw Posted February 9, 2020 Share Posted February 9, 2020 Quite the WAA battle going on here. Got a quick inch flipped to light freezing drizzle/sleet now back to parachutes. Link to comment Share on other sites More sharing options...
madwx Posted February 9, 2020 Author Share Posted February 9, 2020 Heavy rates to wind this one up but only about a half hour left of the snow Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 9, 2020 Share Posted February 9, 2020 Well that was underwhelming 2 Link to comment Share on other sites More sharing options...
sbnwx85 Posted February 9, 2020 Share Posted February 9, 2020 Evaporative cooling knocked me down to 30 degrees. Surprised I’m staying at that mark so long. Best returns about to come through from the southwest. 1 Link to comment Share on other sites More sharing options...
wisconsinwx Posted February 9, 2020 Share Posted February 9, 2020 It’s been just blasting snow from Milwaukee back toward Janesville the last couple hours. I can’t remember the last time I had consistent 30-35dbz returns for a couple hours in a row. I might bust a bit low, already did for MSP. Link to comment Share on other sites More sharing options...
CoachLB Posted February 9, 2020 Share Posted February 9, 2020 1/2 inch over the last hour. Has slowed. Waiting on the rain to wash and rinse. Link to comment Share on other sites More sharing options...
OrdIowPitMsp Posted February 9, 2020 Share Posted February 9, 2020 Finished with 5” imby in south minneapolis. Some of the fluffiest snow I can recall in awhile. It’ll be interested to see what the ratios are. Link to comment Share on other sites More sharing options...
OrdIowPitMsp Posted February 9, 2020 Share Posted February 9, 2020 Biggest totals from the MSP coverage area Link to comment Share on other sites More sharing options...
madwx Posted February 9, 2020 Author Share Posted February 9, 2020 Snow back building of the snow band here with some healthy sized flakes Link to comment Share on other sites More sharing options...
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