Thunderstorm with Freezing Rain! Round #2 has come in. The temperature is hovering between 31 and 32 right now. Here is the radar image with lightning overlay just a few moments ago:
A couple photos from the front yard:
0.50" of freezing rain since this afternoon (as of right now). Here in Dodge City, there is a very healthy coating of ice on everything now, the tree in my front yard is glistening against the street light with icicles aplenty. My driveway is pretty much solid ice as well. The street, though, it just wet still. We are sitting at about 30 or 31 degrees, so like I said earlier this afternoon, we have very slowly inched upward in temperature. A second round of fairly substantial precipitation is shown by the various versions of the RUC and also the GFS after midnight, which may yield another half inch of precipitation perhaps.
29 degrees! Holy cow, the wet-bulb effect certainly did it’s job… after peaking at 32° around 2pm, the temperature had since dropped 3 degrees since the precipitation started. I checked outside to verify the freezing rain, and indeed it is freezing on my mail box, the body of my car, and tree limbs. The grass is even starting to get "crunchy" even at the beginning. There’s a lot of rain to come. The temperature is expected to remain nearly steady all night long… perhaps a very, very slow rise through the night, but I think the temperature will be at or below 32 degrees long enough to create some big problems here in Dodge. Holy cow there’s a lot of precip upstream 
Wow this is going to be a close call. …for here in Dodge. It is shortly before 3pm and precipitation is rapidly approaching with the surface temperature at around 32F. The dewpoint is 27F so there is going to be a very slight "wet-bulb" effect and we may be 31F once the precipitation is underway…. unless we have warmed another degree in the past 40 minutes since the last ob. The latest radar is below. Just waiting to see what happens now! Pretty much all of the models now have us in the 32-34F range for much of the night. Man talk about close.
To be (colder than 32°) or not to be… that is the $million question… literally! I just compared our evening Dodge City sounding with the 6-hr forecast of both the NAM and the GFS. Not good in the boundary layer. In a shallow near-surface layer, both the GFS and NAM are some 5°C too warm (see Img 1)… up to about 2,500ft off the ground. This is so very critical. The GFS is showing a nearly constant 33°F here in Dodge City from late afternoon through the night tomorrow night and into the first part of Tuesday before a secondary cold front pushes through.
The GFS now shows a 1.0 to 1.5" storm total QPF for around here in Dodge City with 2"+ just to the east and southeast of Dodge City. This matches up nicely with the persistent QPF forecast from the Canadian model and its ensemble. It’s a matter of only a few degrees….between plain cold rain….and potentially catastrophic ice accumulation… with all sorts of power outages and trees downed.
Extreme Southeast Kansas to Central Missouri Thunder Ice Storm! Wow, take a look at Springfield, MO radar early this morning. Incredible convection occurring in colder than 32F surface temperatures… and training over the same areas too. There is going to be a narrow swath of 1-2" of ice accumulations over a short period of time. According to the recent SGF LSR, Columbus, KS is experience bigtime problems with power out in the entire community (or close to it) and they are opening shelters with numerous trees/powerlines down from the rapid ice accumulation.
0329 AM ICE STORM COLUMBUS 37.17N 94.84W
12/09/2007 CHEROKEE KS EMERGENCY MNGR
WIDESPREAD POWER OUTAGES REPORTED IN COLUMBUS. SHELTER
OPENING IN COLUMBUS AT THE COMMUNITY CENTER NEXT TO THE
FIRE DEPARTMENT. AREAS OF CREST LINE NOW WITHOUT POWER.
What precip type will it be?? It’s enough to drive a forecaster nuts. It now appears that the near surface layer may warm up just enough on Monday before the precipitation moves in…to perhaps consider plain old cold rain as the precip type? Well, that is what the GFS, the NAM, and extended dev2 RUC13 models suggest. The NAM aside (it is having really bad problems warming the boundary layer too much during the mid-late afternoon amidst shallow cold airmasses), both the GFS (Img 1) and RUC13 (Img 2) look somewhat similar. That said, GFS also has a tendency to overforecast 
temperatures from remnant shallow arctic airmasses as well. On the other hand, the RUC models have done a very good job with surface temperature of recent, even in the 24hr+ time range (some of the experimental RUC versions on the web go out to 36 and even 60 hours). I think Monday will be a little bit warmer than originally thought, but will it be warm enough to sustain plain rain versus freezing rain? Of course, that’s the 64,000 dollar question. Given recent performance of the models, I’d have to lean against a colder solution. There will also be wet-bulb effects when precipitation starts anyway, depending on how dry the surface airmass will be… we will be very near the center of the surface high, so I imagine surface dewpoints will be low.
What’s this upper low going to do?? Man, the 00z run of the Canadian is now showing a really impressive phasing of the the two waves into a big, almost cut-off looking upper low that just sits over the Southwest…thus holding onto precipitation much longer during the day Tuesday. I don’t think anyone (or any model) really knows how this is going evolve! The precipitation progs from the Canadian are still very impressive (see Img 3)
Canadian Ensemble Forecast for late Monday into early Tuesday looks very impressive! Well, I woke up fairly early this morning (still recovering from the midnight shifts), and it is extremely slick outside. The temperature is 26 degrees and radar still shows light freezing drizzle over Dodge City. At any rate, the purpose of this post is to discuss and show the very interesting prediction from the Canadian Ensemble. Very briefly, ensemble numerical prediction is necessary to try to capture the degree of uncertainty in a forecast. The more members of an ensemble of solutions the better, because then you can run statistical analysis on the solutions to come up with means, standard deviations (assess the degree of uncertainty), and even generate composite charts to show local max/min from each members of a certain parameter. The Canadian model, GFS model, and ECMWF models all have their own ensemble "suite" if you will. Only the Canadian and GFS ensemble prediction output are available on the internet. I like the Canadian ensemble very much when it is showing a strong "clustering" signal. I took a look at the 72-84 hour forecast of precipitation for the Monday night-Tuesday wave that will more than likely affect western Kansas. The 12-hr precipitation forecast is actually quite ominous! I remember seeing such impressive QPF (quantitive precipitation forecast) signals from last year’s December 29-30th major High Plains winter storm. (albeit not for such a long period of time like that very rare, extreme event)
For the 12-hour period ending 6am Tuesday 12/11, nearly all 20 ensemble members are showing a significant QPF "bullseye" or axis across the Central Plains. The average maximum within the axis or bullseye from all the members is about 25.6mm , which equals 1.00". Averaging out all 20 members, there is a large 10mm contour (right panel in Img 1) encompassing much of Kansas. A mean of nearly a half inch from all the members is very significant — it’s a very strong signal from the model, and at 84-hours from a global spectral model, it’s something to really take note of. There is substantial confidence in a major winter precipitation event across the central Plains, including Southwestern Kansas Monday night… an some of the early indications from GFS model soundings suggest that much of this may very well be freezing rain, given such impressive warm layer aloft expected to spread north atop the shallow cold near-surface layer. Stay tuned, this could be pretty big!
Monday-Monday Night looks quite interesting now! Wow, the GFS and Canadian 00z model runs this evening paint a rosy picture for winter storm fanatics like myself! The upper level wave formerly referred to as "wave #3" in my previous posts will likely infuse an exorbitant amount ofGulf Moisture with low level trajectories favorable for significant western Plains precipitation. A "kicker" jet-streak digging down the backside (what I guess would call wave #4) will eject the primary storm northeastward in a highly energetic fashion — according to the 84 hour forecast of the latest Canadian and GFS models. 12-hr precipitation accumulation from both models peg a 1.25 to 1.50" max during the 6pm Mon to 6am Tues time frame (see Img 1). The Canadian is farther west, with this maximum occurring between Dodge City and Wichita, whereas the GFS has a narrower corridor of significant precipitation through central Oklahoma. Precipitation type will be a huge dilemna, as it would certainly appear that a warm layer aloft would advect northward overtop the shallow cold airmass. There could be significant sleet and/or freezing rain around portions of Southwest Kansas Monday night.
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