Rain stayed away only on five of the first fourteen days of February in Huntsville. Rain falls on practically a daily basis for the next seven days making a damp month suddenly a very, very wet month. The seven-day rainfall forecast from NOAA’s Weather Prediction Center shows average cumulative totals around seven inches through next Thursday. That could prove to be a serious flooding threat: especially on the two days when most of that rain comes down: Tuesday and Wednesday (20th and 21st).
Short-term rainfall looks light: only spotty showers through most of Friday. Friday’s 70% chance of rain is ‘backloaded’; the best chance of widespread rain comes after sunset through early Saturday morning. Expect a high in the mid-60s Friday with a southwest breeze, a cloudy sky, and some occasional showers.
Where’s this heavy rain coming from? Let’s be clear: 5+ inches of rain over several days – not all at once.
It’s highly unusual to see official NOAA forecasts for more than 6” or 7” of rain without a landfalling tropical system. That’s not even close to what’s happening with this pattern, though. A strong ridge over Florida and Cuba contrasted by a deep ‘trough’ over the western United States puts Alabama and Tennessee under a ‘fire hose’ of moisture next week.
A persistent southwesterly flow aloft, an agitated jet stream with a lot of energy, and moisture supplies from both the Gulf of Mexico and the Pacific likely set up very heavy rainfall in the next seven days.
The biggest rain days as of now look to be Tuesday and Wednesday; those are also the days when some risk of thunderstorms (possibly severe in the region) exists.
The eye-popping forecast totals from NOAA are realistic even if not totally accurate. There’s no way to precisely forecast an exact amount of rainfall; however, these forecasts give us a generally good estimate of what we can expect in a given period.
This could cause some serious flooding problems next week; we’ll be on top of all of that for you!
Some perspective: Seven inches of rain in a seven-day period does not even crack the top-20 of wettest weeks on record in Huntsville. The wettest seven-day stretch on record ended December 23, 1990: 13.45 inches of rainfall!
Just because it hasn’t happened lately doesn’t mean (1) it can’t happen or (2) it’s unprecedented.
Weekend forecast: Rain looks very likely Friday night: some getting as much as 1/2” to 1” of rain through Saturday morning. Showers thin out and it looks cloudy and mild for Saturday afternoon: highs in the upper 50s with a light north wind. Rain moves in again Sunday, and although it looks relatively light for Sunday, some spots may still get more than 1/2” of rain before midnight. Expect morning lows in the 40s and afternoon highs as warm as the mid-60s.