Guess the Precipitation tomorrow and Thursday

[Adam Atkins]

The local Oklahoma City forecasters in the media and at the NWS are tiptoe-ing around any bold precipitation forecasts after last weeks near, but significant miss in the snow forecast. What form do you think the precipitation will mainly fall as?

I'm going with a heavy wet snow after looking at tonights WRF forecast thermodynamics. The entire profile is sub-freezing with a nearly saturated environment. The WRF/NAM nailed the thermodynamics of the last system so I'll go ahead and trust this model's forecast.

 

[Brett Roberts]

I'll go with "seasonal persistence" and say a mixed bag for Norman, with reality being a bit warmer and p-type delineations a bit farther north than forecast immediately before the event.

On the positive side, the existing airmass does seem somewhat colder than the one that was in place for last weekend's bust, with dew points currently in the low to mid teens. And while mid-level warm intrusions have seemingly been underdone on every model for every event this winter, there is more wiggle room on the 00z NAM and GFS soundings than there was the day before the last event, with the GFS showing all levels several degrees below freezing and the NAM only briefly nudging up to near 0°C in the vicinity of 900 mb.

On the negative side, QPF appears light, with no 6-hour period showing more than about 0.10" of liquid equivalent on either model. Therefore, it would seem significant evaporational cooling will be hard to come by if it turns out to be "needed." Also, even the NAM, by far the more accurate (and warmer) of the two U.S. models last go-around, was still not quite warm enough at the warmest levels, and if you tack on another 1-2°C to its current profile between 850 mb and 950 mb it would have a large impact.

So basically, while current model solutions taken verbatim imply the potential for 1-3" of snow for the southern OKC metro area, my pessimistic nature (which has proved justified during each winter weather event so far) is hedging my guess more towards an outcome of snow/sleet at the onset, changing to more of a sleet/rain/frz rain mix, then ending as a period of snow Thursday morning. I'm expecting another nasty coating of half an inch to an inch of pellets and slush that will freeze into a solid slab and become hazardous during the cold blast that follows.