“3 Degree Guarantee”
By Gannon Medwick
Tuesday, August 07, 2007
Today my 3-Degree Guarantee high is a blistering 100 inland! Though I can explain why today will be so hot with relative ease, actually arriving at a forecast of 100 degrees must be done cautiously. Many weather factors can derail a 100 degree day…
Cloud Cover and Rain: There’s no better way to cool a day than with clouds and showers. I must be sure that clouds and showers – if they develop – will do so late enough in the day so as not to preclude the temperatures from soaring to 100. Though I do have a stray thunderstorm in my forecast, I think any such activity will hold off until after 3 or 4 o’clock. By that time, the temperatures will already have had a chance to soar.
Dry Ground vs. Wet Ground: I spoke of the effect soil moisture has on temperature in a previous blog. Despite widely-scattered showers recently, soil moisture is generally low courtesy a dry summer. All else equal, having dry ground favors hotter weather because the sun’s energy can efficiently heat dry ground – and thus the air above it. Wet ground can derail 100 degree weather (Dallas, TX has had an extremely wet summer and has had no 100 degree days this year.)
Climatology: 100 degree days, though not unheard of, are rare in summer. In forecasting a 100 degree day, I need to respect climatology and forecast 100 with care. Average highs are in the upper 80s and low 90s for Eastern North Carolina in early August.
After careful analysis, I think these roadblocks will not be present today, so 100 degrees looks probable! Take care out there. Heat index values will reach a dangerous 110 inland; 100-105 near the coast.
Feel free to respond to this blog! I look forward to reading your comments.
Take care,
Gannon
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