Winter Storm? I'm thinking NOT

Monday, February 12, 11:30AM--

Winter Weather Advisory in effect from 6 PM this evening to 12 PM CST Tuesday...

Weatherdork's Drop Dead Prediction:
60% chance - Rain, with some spotty, slushy snow/sleet/glazing. Messy, but nothing dire.
15% chance - more than 3", but less than 6" snow. School Cancellations.
15% chance - 0-3" of snow/sleet
10% chance - nothing

Drop Dead Prediction Confidence: Medium-High

Onset: Rain to arrive sometime this afternoon/evening....probably sometime after 3PM. It should be light to moderate RAIN. Snow, if any, will come later this evening.

Discussion: Enh....this system is nothing to get all that bent out of shape about. The forecasting from the NWS broke about every rule I have when it comes to making my predictions....that's why I don't think we will get much winter weather here....at least not enough to cause traffic havoc and massive school closings. Here are a few rules from my playbook that made me throw red flags, and doubt their forecast:

Rule: The NWS day-of-storm temperature forecast is always too cold for reality; add 3-5 degrees to what they predicted. The forecasted high for tomorrow is 30 degrees. I just know from experience that this is probably 5 degrees too cold. So lets call it 35 instead. Since water freezes at 32F, too much of this precip will fall as rain.

Rule: Saint Louis is just a little too far East, and a little too far South to get hammered with snow. For whatever reason, geography is against us here in STL. We are about 100 miles too far east to get the great "conveyer belt" moisture surge from the Gulf of Mexico, and about 100 miles too far south to get cold enough air to cause winter-type precipitation. That conspires against us perfectly for this storm system.

Rule: Never sound the alarm until you see the flakes/drops falling from the sky. Last night, the NWS issued a freezing rain advisory in effect from 6AM until 12 Noon today. Do you see any freezing rain? No. How about plain-old rain? Nope. The NWS stoked the panic flames before there was any reason to. Whenever they are THAT wrong about something, I always doubt the whole forecast.

Rule: If thunderstorms are predicted south of St. Louis, we won't get that much moisture here. Thunderstorms are in the forecast for Texas, Oklahoma, Louisiana, Arkansas, and Mississippi. While this does not mean it is impossible for moisture to reach our area, it is my experience that thunderstorms south of Missouri tend to steal the moisture that was headed our way.

Rule: Never make dire winter forecasts for St. Louis based solely on computer models. The NWS has been predicting this winter storm for 4-5 days now, well before the low pressure system ever even came ashore in California. It looks like the models were at least partially right here, though. It was a fairly good prediction....the models were just a little too cold.

Rule: When forecasting a Southwest Storm, never predict snow for St. Louis unless you are predicting snow for Farmington. This rule is related to the "STL is a little too far south" rule. But it is my experience that the forecasters wrongly predict where that "freezing line" will be, putting that line 50-100 miles too far south. So, my rule of thumb is if Farmington doesn't also have snow in the forecast, then they probably don't have a good handle on where that freezing line will really be, which means mostly rain for STL. And while Farmington has snow in the forecast for tomorrow....well, I just don't think they're right!

Anyway, there you have it. G-d, I want to be wrong....I HOPE I am wrong...but I think we just have a rain-maker on our hands.

-WD