Man vs. Machine, Day 2

So far, yesterday's forecast is looking pretty good. I find it odd, that when I last did the forecast contest, it was raining. I do it this time, and it rains again. Anyway, I'll give the verification information shortly after 7:00pm CST, after the data is reported. I may have to do a site close to Alton for precipitation verification, though. Alton/St. Louis Regional Airport is not reporting any precipitation, and I know for a fact it has been raining since before noon. It has mostly been light rain, but still there should be some measurable amount by now. All that aside, it is time for the next forecast. This forecast period is between 7:00 pm CST March 8-7:00 PM CST March 9.

What a difference a day can make in the jet stream. Yesterday there weren't any real noticeable troughs or ridges at 500 mb, just shortwave troughs. Today's 500 mb analysis provides a completely different story. There is a fairly large trough sitting across the central United States. The data from 7:00 am CST, places the edge of the trough near the Kansas/Missouri border. Behind the trough is a ridge over California.

The 850 mb map still shows strong southerly flow off the Gulf of Mexico. This will continue to provide a nice moisture inflow for the forecast area. There is also warm air advection at the 850 mb level. All this combined with the current cloud cover should help keep the nighttime low at or above last night's low. (Which was 40). This will probably aid in keeping rain around tomorrow, although it should mostly be light rain, probably nothing heavier than showers.

As for the surface map, there still isn't too much happening. The low from yesterday actually moved slightly through Texas. At the synoptic scale view, it appears to have a stationary front, a dryline, and a cold front. However, once I examined this system at the mesoscale level, I still felt it was necessary to place a warm front across Arkansas into Tennessee, rather than a stationary front. This front is giving some forcing to the system, which means it is helping to maintain the rain.

Visible satellite is showing what looks like convective towers out in western Missouri into Kansas. Radar imagery out of the Kansas City NWS also shows storms. However, they are pushing north, and should not affect our area at all. Other than that, there is just a large cloud shield on satellite, and radar imagery out of the St. Louis NWS shows a large area of precipitation with some areas being slightly stronger than others. A look at the national view of the visible satellite imagery shows the large cloud shield over the central United States. Based on this loop, I feel confident in saying that there will still be cloud cover tomorrow, but it may push out late Wednesday night into the morning on Thursday.

Now it is time to put it all together. I put a large amount of values into a temperature correction table, which helps me forecast temperatures based on current and predicted weather conditions. This takes into account many factors, such as cloud cover, precip, wind, and more. These values either add or subtract a value to the temperature, and it is a pretty accurate way to forecast temperature. That being said, after working the numbers on the chart and factoring in the dew point, I am forecasting tonight's low to be at 39 degrees, and I am forecasting tomorrow's high to be at 51 degrees. It looks like we will still have showers and light rain, but I think we should have a relatively low amount, probably somewhere between .15-.25" of rain.

The Wednesday Forecasts:

Man:
Low: 39
High: 51
Weather: Showers and light rain
Precip: .15-.25" of rain

GFS:
Low: 45
High: 50
Weather: 100% chance of precip
Precip: .5-.99" of rain

NAM:
Low: 43
High: 45
Weather: 90% chance of precip
Precip: .25-.49" of rain


Time will tell as the forecast contest keeps on going. Forecast verification will be placed in the comments section of this post. Just like yesterday, I hand analyzed my own maps, using the same site for the raw data. I might post them after the contest, just because it takes a while to do them indiviually. That's all for now. At least, until the next forecast!