Forecast Central

Forecast of the Day • A National Weather Forecasting Contest

Tomorrow: Saturday April 11, 2020

There is not a Forecast of the Day contest for tomorrow.


Today: Friday April 10, 2020

Assignment: Predict the 24 hr minimum temperature (deg F) for Yellowstone, WY (KP60)

I'm a little puzzled by Friday's minimum temperature forecasts for Yellowstone, Wyoming. The GFS runs predict a low of about 25 F, but the NAM predicts about 15 F. The problem is that I don't really see why the NAM is going that low. But I could easily be wrong, so let's forecast Tmin for Yellowstone and see how it comes out.

Forecasts for Yellowstone, WY (KP60)
Forecaster Tmin, deg F (error) Comment Day Score
OBSERVED 24 Data through 0700 UTC
GFS-MOS-00-DAY00 26 (-973) 3.1
GFS-MOS-00-DAY01 26 (-973) 3.1
GFS-MOS-12-DAY02 26 (-973) 3.1
GFS-MOS-18-DAY02 25 (-974) 2.8
GFS-MOS-06-DAY01 25 (-974) 2.8
GFS-MOS-06-DAY02 25 (-974) 2.8
GFS-MOS-12-DAY01 24 (-975) 2.6
NAM-MOS-00-DAY00 21 (-978) 1.8
Lizzie15 18 (-981) 1.1
NAM-MOS-00-DAY01 18 (-981) 1.1
Blake15 17 (-982) 0.8
NAM-MOS-12-DAY01 17 (-982) 0.8
NAM-MOS-12-DAY02 15 (-984) 0.3

Most Recent Completed Forecast of the Day: Wednesday April 8, 2020

Assignment: Predict the 24 hr maximum temperature (deg F) for Lufkin, TX (KLFK)

I keep an eye on the hottest and coldest daily observations in the U.S., and the national high is usually somewhere in the desert Southwest (like Yuma, AZ), someplace in South Texas, or someplace in Florida. But the current GFS MOS forecasts are showing that Lufkin, Texas (in Deep East Texas, not South Texas) could have the highest temperature on Wednesday. It's also a little strange that the NWS page for Lufkin shows flood warnings all week, which doesn't usually go with high temperatures. Anyway, let's predict Wednesday's Tmax for Lufkin and see what happens.

Question: What is it about the desert Southwest that results in such extreme high temperatures? Please don't say "because it's the desert" -- what is it about the desert that produces those extremes?

What Happened?

Well Lufkin was foggy/misty/overcast until 1 pm. It finally started clearing and the temperature increased, but the slow start meant that they reached only 87 F, lower than any of the model statistical forecasts.

Of course the desert is often cloud-free, leading to the maximum possible amount of solar radiation. But probably the most important thing is that the lack of rainfall means that the soil stays very dry for long periods in the desert. Given an equal amount of solar radiation between a site with a wet climate and lots of vegetation (e.g. Florida) and a dry desert site, the wet site will warm up less, because some of the energy is used to evaporate water from the soil and drive transpiration from the vegetation, rather than increasing the air temperature.

Forecasts for Lufkin, TX (KLFK)
Forecaster Tmax, deg F (error) Comment Day Score
OBSERVED 87 Tmax FINAL (minor problem).
1. Grace15 87 (0) 3.4
1. Joscelyn15 87 (0) 3.4
3. Austin15 88 (1) There isnt enough water in the sand to control the temperature 3.0
3. Anna15 88 (1) 3.0
3. T-Dawg15 86 (-1) 3.0
3. Jasper15 86 (-1) 3.0
3. Leah15 88 (1) 3.0
NAM-MOS-00-DAY00 89 (2) 2.7
NAM-MOS-12-DAY01 89 (2) 2.7
8. Mathison15 89 (2) 2.7
8. Lizzie15 85 (-2) 2.7
8. Gus15 89 (2) 2.7
8. Dorothy15 89 (2) 2.7
8. Eavenly15 85 (-2) 2.7
GFS-MOS-00-DAY00 90 (3) 2.3
13. Gianni15 90 (3) 2.3
13. Elizabeth15 84 (-3) 2.3
NAM-MOS-00-DAY01 90 (3) 2.3
GFS-MOS-18-DAY01 91 (4) 2.0

Earlier Contest Days

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