Rain chances expected to increase this weekend
TALLAHASSEE, Fla. (WCTV) - The Big Bend and South Georgia will likely see another storm system moving into the region during the weekend. The system will bring a threat of higher rain chances, but a severe weather threat remained uncertain as of Wednesday.
A trough of low pressure in the mid-to-upper levels of the atmosphere was in the Pacific Ocean west of the Northwest U.S. coast based on upper-air analysis Wednesday morning. Large-scale models such as the American GFS and the European (ECMWF) call for the trough to move through the northern Rocky Mountains and dig southeast through the Plains Friday into Friday night. The lift associated with the trough will help develop a surface low in the Plains by Friday and move into the Southeast Saturday.
With the forecast for the low to move into the Deep South, guidance models showed an increase in atmospheric moisture ahead of it as soon as Saturday night. Models also hinted at a potent feature called a low-level jet, which is an ingredient that would help to develop rotating thunderstorms. Strong upward velocities would also bring the risk of heavy rainfall with higher moisture content.
BUT, a key ingredient is missing in the guidance: Instability. Convective energy remained low or nonexistent. This could be, in part, because of the timing — Saturday night into early Sunday — where instability will be the lowest.
Also, there may not be enough time for the atmosphere locally to gain warm, moist air. Area-wide atmospheric profiles in the models hint at temperatures at the surface in the 50s and 60s, which does give doubt for severe weather.
The timing of the higher rain chances, so far, will start Saturday night and last through Sunday afternoon. Ensemble model averages hint at rainfall totals in the viewing area ranging from half an inch to nearly an inch with higher amounts farther north, while operational runs call for between a half-inch to nearly 2 inches.
Given the deeper moisture and robust lifting mechanisms, 1 to 1.5 inches of rain in most locations in the Big Bend and South Georgia, with a chance of higher amounts locally, would be a safe bet.
Given that the forecast event is three to four days away, specific details could change that would allow for a change in the outcome and timing of rainfall. The Pinpoint Weather Team will monitor the progress of this expected storm system through the rest of the week and into the weekend.
This story was updated to include a video forecast with visual details.
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