NwWhiteOut Posted January 12, 2017 Share Posted January 12, 2017 Probably gonna have to nowcast with all this, Temp here starting dropping early this morning. Expected highs were 56 today, its 42 here now. I'm still not worried but it seems northern arkansas near the border could see some freezing drizzle tonight by what I am reading/hearing. Link to comment Share on other sites More sharing options...
JoMo Posted January 12, 2017 Share Posted January 12, 2017 1 hour ago, Wx 24/7 said: I am just not comfortable with this situation considering the variance in solutions from this system. Whoever said that it may be a nowcast situation was certainly right. I know most events usually are, but this one maybe more so than normal. To me, one of the key things I will be watching is if we warm up as forecast this afternoon. That will give me an indication if the cold air is a bit stronger than initially forecast. Been stuck at 28 for hours here. The airport just dropped to 27 it looks like. The GFS doesn't capture low level airmasses very well because of it's more coarse grid. The NAM/HRRR and other short range guidance would do a better job. With that being said, it would have to warm 4 degrees here in the next 30 mins for it to match the latest full HRRR run for noon. Link to comment Share on other sites More sharing options...
JoMo Posted January 12, 2017 Share Posted January 12, 2017 12z Euro is coming in colder than last nights run for at least Friday. Sat may be a bit colder around OKC area. Link to comment Share on other sites More sharing options...
MUWX Posted January 12, 2017 Share Posted January 12, 2017 I'm surprised warnings aren't posted yet. Surely within the next hour or two. Link to comment Share on other sites More sharing options...
nrgjeff Posted January 12, 2017 Share Posted January 12, 2017 Warnings or advisories should come with the afternoon forecast products. They will likely go Warning with quarter inch or greater ice accretion forecast. That said, Missouri may not get the 3/4"+ amounts advertised. Friday precip is light and intermittent. Saturday the WF will try to lift north at the onset of the more steady to moderate freezing rain and rain. Still 1/4" to 1/2" is a damaging ice storm. Quarter inch is warning criteria, so it is an easy call regardless. Even shaving a quarter inch, I like the chart STL posted for relative threats of ice impacts. Chart appears coordinated with other Missouri offices. ICT also posted an ice accretion chart. If one extrapolates into Missouri, it is not as much as the STL chart. Again, the lower amounts are still damaging. Central Kansas had a bullseye of particularly high ice accumulation. However latest NWP show warmer air mixing down with the heavier rain. Euro is a notable exception, but it will depend on the rate of the surface high retreat. Link to comment Share on other sites More sharing options...
NJ_Ken Posted January 12, 2017 Share Posted January 12, 2017 The current forecast for Central Oklahoma (as per the OUN forecast discussion) is based on temps being above freezing overnight and wetbulbing down below freezing once the rain starts in the a.m. Since the initial rainfall is likely to be light, they were expecting that wetbulbing to take some time, which in turn would limit ice accretion (again this is for Central OK... to the north and west, it is going to be awful regardless). Noon temperature at OKC is 32 F even with a bit of sun out there. Assuming the sun stays out for the afternoon, we might tick up a few more degrees, but I am thinking even a high of 40 F is now doubtful. And temps will likely drop right off after sunset. It is looking increasingly like we will be below freezing... perhaps by several degrees... from the minute the rain starts. That could make things MUCH worse for the a.m. rush tomorrow.... and for the following 24 to 36 hours during which temps may well stay below freezing. The only saving grace here is that this is going to be more like the east coast ice storms I grew up with: The cold air will start to get stale and eventually the warm air WILL win out and temps WILL get above freezing and melt everything. The only question is how long it will take and how much trouble we see before that happens. Link to comment Share on other sites More sharing options...
KC metro Posted January 12, 2017 Share Posted January 12, 2017 12z NAM and GFS don't agree on the amount of ice accumulation for Kansas City. Link to comment Share on other sites More sharing options...
jojo762 Posted January 12, 2017 Share Posted January 12, 2017 3 minutes ago, KC metro said: 12z NAM and GFS don't agree on the amount of ice accumulation for Kansas City. I wouldn't pay too much attention to what each model shows for Ice accumulation... just know that .25" to 1" of ice are likely/possible. Link to comment Share on other sites More sharing options...
MUWX Posted January 12, 2017 Share Posted January 12, 2017 I'm a little surprised that Sgf didn't pull the trigger on a warning for the southern counties. Trending colder, but drier according to their forecast. Link to comment Share on other sites More sharing options...
jojo762 Posted January 12, 2017 Share Posted January 12, 2017 In case you missed it, SGF just issued an Ice Storm Warning for much of their CWA for 1/2" to 3/4" of ice... expect other WFOs to follow suit with ISW over WSW. Link to comment Share on other sites More sharing options...
jojo762 Posted January 12, 2017 Share Posted January 12, 2017 LSX followed suit, ice storm warning, including all of the St. Louis metro, for 1/4-1/2" of ice. Link to comment Share on other sites More sharing options...
OUGrad05 Posted January 12, 2017 Share Posted January 12, 2017 If temps continue trending cooler than model forecasts that's going to create a pretty big mess tomorrow for the OKC and Tulsa metros. The trend doesn't seem like a good one in this case. Ice is awful to deal with and NW OK appears to be on the verge of an epic event. Link to comment Share on other sites More sharing options...
JoMo Posted January 12, 2017 Share Posted January 12, 2017 Looks like KC/STL/Topeka have gone Ice storm warning as well. Link to comment Share on other sites More sharing options...
jojo762 Posted January 12, 2017 Share Posted January 12, 2017 ICT appears to be favoring the warmer GFS. Per 20Z AFD... Bold. Link to comment Share on other sites More sharing options...
JoMo Posted January 12, 2017 Share Posted January 12, 2017 OKC area: Link to comment Share on other sites More sharing options...
Weatherdemon Posted January 12, 2017 Share Posted January 12, 2017 Norman NWS: Freezing Rain Advisory for: BECKHAM-WA****A-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN- CLEVELAND-POTTAWATOMIE-HARMON-GREER-KIOWA-JACKSON-COMANCHE- INCLUDING THE CITIES OF...ELK CITY...SAYRE...CORDELL... BURNS FLAT...SENTINEL...ANADARKO...HINTON...YUKON...CONCHO... EL RENO...MUSTANG...OKLAHOMA CITY...CHANDLER...STROUD...PRAGUE... MEEKER...DAVENPORT...WELLSTON...CHICKASHA...TUTTLE...PURCELL... NEWCASTLE...BLANCHARD...NORMAN...MOORE...SHAWNEE...HOLLIS... MANGUM...GRANITE...HOBART...SNYDER...ALTUS...LAWTON * ICE ACCUMULATION...ICE ACCUMULATIONS BETWEEN ONE-TENTH TO NEAR ONE- QUARTER INCH... ESPECIALLY ALONG AND NEAR INTERSTATE 4 ISW for: HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD- NOBLE-ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE- INCLUDING THE CITIES OF...BUFFALO...LAVERNE...ALVA...CHEROKEE... HELENA...CARMEN...MEDFORD...POND CREEK...LAMONT...WAKITA... PONCA CITY...BLACKWELL...SHATTUCK...ARNETT...GAGE...FARGO... WOODWARD...FAIRVIEW...ENID...PERRY...CHEYENNE...HAMMON... SEILING...VICI...TALOGA...LEEDEY...WEATHERFORD...CLINTON... WATONGA...GEARY...OKEENE...KINGFISHER...HENNESSEY...OKARCHE... GUTHRIE...STILLWATER * ICE ACCUMULATIONS...ICE ACCUMULATIONS OF ONE-QUARTER TO ONE- HALF INCH. THE HEAVIEST ACCUMULATIONS ARE EXPECTED SATURDAY. Link to comment Share on other sites More sharing options...
NJ_Ken Posted January 12, 2017 Share Posted January 12, 2017 8 minutes ago, JoMo said: OKC area: They've moved everything south incrementally over their early a.m. products, but literally only a few miles. I think as this gets closer and we can do some real nowcasting, they may have to move this a few more ticks to the south. I also think that, once the warm air advection gets going, it will warm fairly quickly in Central OK. In other words, I think things will be worse than expected into Saturday and then rapidly get better than hoped by late Saturday. Link to comment Share on other sites More sharing options...
KC metro Posted January 12, 2017 Share Posted January 12, 2017 Kansas City went ice storm warning as well for .25 to .75 ice accumulation. Link to comment Share on other sites More sharing options...
OUGrad05 Posted January 12, 2017 Share Posted January 12, 2017 26 minutes ago, jojo762 said: ICT appears to be favoring the warmer GFS. Per 20Z AFD... Bold. Wonder what they're seeing that makes them lean that direction. Link to comment Share on other sites More sharing options...
NwWhiteOut Posted January 12, 2017 Share Posted January 12, 2017 Freezing rain advisory for tonight just to my north about 20 miles or so Link to comment Share on other sites More sharing options...
Weatherdemon Posted January 12, 2017 Share Posted January 12, 2017 Freezing rain advisory for counties in the I44 corridor in NE OK. ISW for areas north. Link to comment Share on other sites More sharing options...
KC metro Posted January 12, 2017 Share Posted January 12, 2017 I'm not trying to lessen the impact but the 18z NAM and 12z GFS are worlds apart on ice accumulation for certain areas. GFS has heavy accumulation for much of Kansas whereas the NAM would shift the heaviest accumulation into southern KS and NW Ok. Not saying this is accurate but worth watching to see if other model shift the heavier precip southwest ward. Link to comment Share on other sites More sharing options...
OUGrad05 Posted January 12, 2017 Share Posted January 12, 2017 44 minutes ago, KC metro said: I'm not trying to lessen the impact but the 18z NAM and 12z GFS are worlds apart on ice accumulation for certain areas. GFS has heavy accumulation for much of Kansas whereas the NAM would shift the heaviest accumulation into southern KS and NW Ok. Not saying this is accurate but worth watching to see if other model shift the heavier precip southwest ward. That's being driven by significantly different surface temp profiles between the two models. When looking at accuracy with this system 24hrs out, the NAM has been more accurate. For example on the 18Z NAM run yesterday, the forecast was for temps at this time of approximately 42* with the GFS at 46. Actual temp? 39* Link to comment Share on other sites More sharing options...
Cerakoter1984 Posted January 12, 2017 Share Posted January 12, 2017 For what it's worth, Tulsa not doing a great job of convincing me they went even remotely close to far enough southeast now. Link to comment Share on other sites More sharing options...
KC metro Posted January 12, 2017 Share Posted January 12, 2017 1 hour ago, OUGrad05 said: That's being driven by significantly different surface temp profiles between the two models. When looking at accuracy with this system 24hrs out, the NAM has been more accurate. For example on the 18Z NAM run yesterday, the forecast was for temps at this time of approximately 42* with the GFS at 46. Actual temp? 39* I'm thinking it also has to do with how far the heavier precip makes it northward. For example, KC stays below freezing for most of the event yet the NAM is calling for less than .10 which means the heavier precip doesn't make it as far north. The GFS on the other hand calls for .25 to .50. Link to comment Share on other sites More sharing options...
OUGrad05 Posted January 12, 2017 Share Posted January 12, 2017 29 minutes ago, KC metro said: I'm thinking it also has to do with how far the heavier precip make is northward. For example, KC stays below freezing for most of the event yet the NAM is calling for less than .10 which means the heavier precip doesn't make it as far north. That's a good point it keeps most of the precip south of the KC metro Link to comment Share on other sites More sharing options...
OUGrad05 Posted January 12, 2017 Share Posted January 12, 2017 38 minutes ago, Cerakoter1984 said: For what it's worth, Tulsa not doing a great job of convincing me they went even remotely close to far enough southeast now. They may do another update later this evening. Model divergence is still significant, they're leaning a bit towards the GFS on temp profiles it seems. Link to comment Share on other sites More sharing options...
MUWX Posted January 12, 2017 Share Posted January 12, 2017 Ky3 just showed a model that had the heaviest ice south of cassville through tomorrow night. The model differences for a storm that is less than 12 hours from starting are crazy. Link to comment Share on other sites More sharing options...
JoMo Posted January 12, 2017 Share Posted January 12, 2017 Euro weeklies coming in..... Looks like we're in retrogression mode for Feb. These might be the best looking weeklies of the year. Looks like a stormy late Jan with a low retrograding from the GOA area back to the Aleutians. This is going to pop a -EPO, with troughing in the central and eastern US. Signs of a -AO forming after the first week of Feb as well with continued central and eastern US troughing. 850 MB temps are below normal from late Jan into late Feb at the end of the run. EDIT: Temps: Warm through late Jan, and then colder than normal through the entire month of Feb. Link to comment Share on other sites More sharing options...
Wx 24/7 Posted January 12, 2017 Share Posted January 12, 2017 So, funny item for the day... our overnight low according to the NWS is 29. Well, we are already 28º in Monett. Just food for thought. Link to comment Share on other sites More sharing options...
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