WKU Meteorology

I haven’t changed my thinking with regards to the storm for Monday and Tuesday. The double-jet structure of the storm that I talked about here will bring 1-2″ of rain to Bowling Green Monday and Monday night. We may also have temperatures >50 degrees Monday afternoon as Gulf air surges northward ahead of the storm. This will be the first warmer than normal day since January 27th, breaking a streak of what will be 15 consecutive days of below normal temperatures. Fresh arctic air will move in Tuesday morning, which will turn any remaining rain into snow. Some Minor accumulations are possible. For a more detailed analysis of this storm, see the discussions of the NWS and WNKY. Continue reading →

Update: Sunday, 2/4 9:54 pm
I will score how well the NWS and MOS fared against the arctic air mass over the Saturday-Wednesday period. I will group the Bowling Green and Lexington forecast by day to make scoring easier. By the way, I made a pretty bad call on the high Saturday. I neglected to account for the lack of cold air advection (CAA) into Kentucky at 850 mb. Since we’re at the bottom of the trough, our winds aloft were westerly. Note how the winds aloft shift more to the northwest as the trough axis swings through the region on Sunday/Monday. This NW flow coincides with the coldest air of the season. I should have noticed this before I criticized the NWS forecast for Saturday. I am somewhat justified though as even the NWS admitted they were too warm with temperatures for the weekend in today’s discussion…

MAIN STORY MONDAY MORNING WILL BE THE COLD LOWS…0-5 ABOVE IN THE NE TO 5-10 ABOVE IN THE SW. THIS IS
CONSIDERABLY COLDER THAN THE MOS AS ITS SUFFERING FROM A WARM BIAS OF LATE. WEAK RIDGING WILL BUILD IN FOR MONDAY ALLOWING SKIES TO BECOME PARTLY SUNNY. HOWEVER…EVEN WITH GOOD INSOLATION…TEMPS NOT GOING TO GO UP VERY MUCH. TRENDED TEMPS DOWN FROM PREVIOUS FCST WITH MID AND UPPER 10S ACROSS THE NORTHERN HALF TO THE LOWER 20S ACROSS THE
FAR SOUTH. LOOKS LIKE COLDEST NIGHT WILL BE MONDAY NIGHT/TUESDAY MORNING WITH LOWS VERY CLOSE TO 0 IN THE BLUEGRASS REGION…COULD EVEN SEE SOME BELOW ZERO READINGS IN SHELTERED AREAS.

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The students in my Synoptic Meteorology course last fall know my feelings about the ability of model output statistics (MOS) to accurately predict temperatures of an arctic outbreak. Even better, my students know how I feel when forecasters use those MOS values even though they have no known basis in reality during arctic outbreaks. In fact, the inability of MOS to accurately predict highs and lows during arctic outbreaks is so well known there have been a number of research articles to prove this, as seen here, here and here. If this problem is so well known, then why is the NWS forecasting temperatures for much of Kentucky over the weekend that are in some cases higher than the MOS ensemble average? Continue reading →

As a forecaster, the goal is to get the meteorology right (storm track, thermal profile, dynamics) when a storm is approaching. Once the meteorology is correct, it is fairly easy to predict the weather (temperatures and precipitation) and you will generally be correct 99% of the time.

When you get the meteorology exactly right but incorrectly predict the weather, all you can do is shrug your shoulders and chuckle. Continue reading →

The NWS, WNKY, and WBKO all mention that any snow that falls Thursday will mix with and possibly change over to rain during the afternoon. One reason they may be concerned about this is that as I mentioned in a previous post, there has been a model bias this winter that has often overestimated how much cold air will be present during all of the “near-miss” snow events we have had. To me, this appears to be a form of logical fallacy known as “proof by example”. Continue reading →