CULLMAN COUNTY – The National Weather Service has issued a high wind advisory and flash flood watch ahead of a weather system moving into the area, expected to dump up to 3 inches of rain on Cullman County Thursday and Friday, accompanied by gusting winds that could topple trees and damage structures.
According to the NWS Huntsville online forecaster’s discussion page, Thursday evening to Friday morning is the main point of concern for weather over the next several days. A low pressure system over the Texas/Oklahoma panhandle region drifting to the northeast will send substantial rain to north Alabama, expected to peak during the overnight hours. Quantitative precipitation forecast models currently indicate 1 to 3 inches of rain, with the heaviest amounts falling close to the Cullman County area south and east of Huntsville, due to more prolonged rainfall in the area.
Models indicate “a very small possibility for strong/severe storms, due to very strong shear in place; however, for now, it still appears that stable air from the wedge ridge will inhibit surface- based instability. Still, there is sufficient elevated instability and more than enough shear for isolated/scattered storms. Rain will slowly taper off Friday as the cold front pushes east.”
Rainfall is expected to ease up or even stop Friday night, but could crank back up at lesser intensity to drop another half inch of rain on our area over the weekend.
According to the latest NWS forecast, models indicate that “light rain will develop to our south and then move northward, reaching northwest Alabama by daybreak on Thursday. Rain chances will increase through the day and into the overnight hours on Thursday . . . Latest guidance would suggest that we will see at least one break in the more widespread precip(itation), potentially Thursday afternoon, before even heavier rainfall moves in Thursday night.”
Less than one-tenth of an inch of rain is expected to fall before noon Thursday, but the afternoon will see almost half an inch. Sustained winds throughout the daylight hours will range from 13 to 15 miles per hour, gusting possibly as high as 35.
Rains will come in hard Thursday evening, dropping an estimated 1.2 inches between 6 p.m. and midnight. Another six-tenths will fall before 6 a.m. Friday. Sustained winds will start in the evening at around 12 mph and taper off overnight. Gusts will mostly remain below 20 mph, but some higher speeds could occur.
On Friday, according to the models, a “cold front will swing through the TN Valley, with rain coming to an end by Friday afternoon.
“Looking at the potential impacts with this system, the organized severe threat continues to be rather low . . . while there might be scattered thunderstorms in the widespread showers, even the thunder chances appear low.
“The biggest threat continues to be the heavy rainfall. Moisture will be very high, no question, and the TN Valley will be within a favorable location within the jet to see some heavy rain . . . We are still looking at 1 to 3 inches of rain, but locally higher amounts are likely. If the 3 inches or less amounts are realized, the area should be able to handle that, with only minor nuisance flooding and minor rises on area rivers. But, to err on the side of caution, the setup still warrants a higher attention to a flood threat and will continue to mention that in our HWO (hazardous weather outlook).”
Expected impacts on the area
Strong winds will create hazardous driving conditions throughout the day Thursday. According to the forecast, “Vehicles should exercise extreme caution when driving at this time, especially in higher elevations where wind speeds and directions can rapidly change.
“Multiple episodes of heavy rainfall Thursday and Friday will, according to the forecast, “result in nuisance flooding in low lying and flood prone areas. Creeks and rivers may rise into action or minor flood stage. Those with interests in flashier basins should closely monitor river gauges and forecasts.”
Trees will face a particular threat from the combination of wind and rain. According to the forecast, “Moist soils from prolonged rainfall combined with strong and gusty winds will create favorable conditions for shallow trees to be uprooted.”
Flood watch and wind advisory issued
At 3:04 p.m. Wednesday, NWS Huntsville issued a wind advisory to be in effect from midnight Wednesday to midnight Thursday for the following counties and cities: Lauderdale, Colbert, Franklin, Lawrence, Limestone, Madison, Morgan, Marshall, Jackson, DeKalb, and Cullman; including the cities of Florence, Muscle Shoals, Sheffield, Tuscumbia, Russellville, Red Bay, Moulton, Town Creek, Athens, Huntsville, Decatur, Albertville, Boaz, Guntersville, Arab, Scottsboro, Fort Payne, Rainsville and Cullman.
According to the advisory statement, “A Wind Advisory means that sustained wind speeds of at least 25 mph for 3 hours, or gusts of at least 35 mph, are expected across the affected area. Winds this strong can make driving difficult, especially for high profile vehicles. Use extra caution. In addition, ensure all loose outdoor objects remain secure, including patio furniture and trash cans.”
Immediately following the wind advisory, NWS issued a flash flood watch for the same locations from 6 p.m. Thursday evening to 9 a.m. Friday morning. The watch declaration included the following statement:
“A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.”
Cullman EMA monitoring situation
Cullman EMA Director Phyllis Little informed The Tribune that her agency is monitoring the situation and is receiving regular updates from NWS Huntsville. She encouraged county residents to watch for further alerts and to exercise caution in low-lying areas.
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