Man vs. Machine Week, Day 1

It's time to start the Man vs. Machine weather forecast challenge for this week. This is the first day of the forecast challenge. Just some quick reminders, the forecast is for Alton, IL. Also, I am not allowed to use models or model produced data. After I make my forecast, the model forecasts will be displayed, with numerical values coming from the model's MOS (Model Output Statistics) data. The competition is between:
1. The GFS (The Global Forecast System)
2. The NAM (The North American Mesoscale [model])
3. Me

Alright, here it goes. Starting off at the 500 mb jet stream, there isn't too much going on. There aren't any real big troughs or ridges, but there are a few shortwaves troughs over Kansas and Colorado. These will probably help kick up some weather sometime tomorrow afternoon, as they approach the area. The next layer I want to look at is the 850 mb layer. What I find of importance here is the southerly flow off the Gulf of Mexico. It is strong over eastern Texas and across Louisiana, but as it hits the Ozarks, the winds take a turn to the east. That should provide some moisture tonight and tomorrow. Combined with the 500 mb shortwave troughs, that could provide chances of rain tomorrow. The shortwaves help with forcing or lift, and 850 flow gives moisture, so moisture and lift should be present tomorrow.

The next area I want to look at is the surface map. Really not too happening on the surface map either. There is a system in New England, but it is moving out of the US. Then there is a strong high pressure located around James Bay in eastern Ontario. There is a low located over the Rocky Mountains, but the low I am most interested in is located just south of the Oklahoma panhandle. With this low, I noticed what seems to be a weak warm front. There is a slight wind change, and a slight temperature gradient. It's nothing that jumps off the map, but I feel this was strong enough to place a front there. The only other noticeable feature with this system is the dryline down western Texas back into Mexico.

The visible satellite imagery shows a fairly large area of cloud cover over the central United States. There is a little bit of a break over eastern Missouri, which means Alton may get a little bit of sunshine later on today. The next area of cloud break is back in central Kansas. The radar shows very little going on. It looks mostly like a few light showers over central Missouri, and maybe some really light showers in central Illinois.

Now is when everything starts to roll all together. We've got moisture coming in from the Gulf of Mexico. There are some shortwave troughs at 500 mb, which should help with forcing. The low in Texas should push northeasterly, which would put Alton north of the warm front tomorrow. I don't really see the cloud cover breaking up anytime soon. I would say there is a chance of rain and thunderstorms tomorrow afternoon. There isn't strong moisture here, but it should be enough for showers with some storms, so I'll put my rain amount around .5 inch. (Give or take .05 inches).

Now the real challenge, the temperatures. For the high, I am going to look at the surface map for some guidance. The temps are mostly in the upper 40s north of that warm front. With the cloud cover, you're not going to get the sun to warm up the surface like it would on a clear day. The current temp in Alton is 41. It is mostly cloudy with a bit of sun breaking through. The clouds overnight will help maintain a warmer temp. Tomorrow's high should be in the upper 40s. I'll go with a high of 49. As for tonight's low, it can't fall below the dew point, so that helps establish a lower limit. The current dew point is 34. With some moisture advecting in, that should raise the dew point a little. With current dew points south of here not being too much higher, I'll put tonight's low at 37. Since the new day in Zulu time is at 7 pm, that is when I will grab the data for verification. The next forecast period will start at 7pm CST March 8 and go to 7pm CST March 9.

So Man forecast:
Tonight's low: 37
Tomorrow's high: 49
Conditions: Showers and thunderstorms
Precip: around .5 inch (+/- .05")

GFS:
Low: 34
High: 57
Weather: 70% chance of rain
Precip: .1-.25" of rain

NAM:
Low: 35
High: 55
Weather: 80% chance of rain
Precip: .1-.25" of rain

And just for comparing the NWS in St. Louis Point forecast:
Low: 36
High: 55
Weather: 60% showers with 90% storms Tuesday night
Precip: Not listed.

By the way, I linked up the maps I normally do after the discussion, if you want to see what type of data I used here are the links. [Surface US and Local ] [500 mb] [850 mb]I made a mistake of trying to analyze the maps in Microsoft Paint, which works, but makes them harder to read. Tyring to save on some paper. I'll post the forecast verification in the comments section after the forecast period is over, and I'll have a new discussion up tomorrow.