Both of the weather offices that split Southwest Florida put the weekend flood bullseye north of Lee and east of Collier, and neither county is under a watch, advisory or warning

Neither Collier nor Lee County was under a flood watch, advisory or warning on Friday morning. The only active National Weather Service product covering either county was the rip current statement on the Lee County Gulf beaches, which runs until 8 p.m. on Saturday.

Both of the forecast offices that divide Southwest Florida published their reasoning overnight, and both placed the heaviest flood risk somewhere other than here.

Lee County falls under the Tampa Bay Ruskin office. Its discussion, transmitted at 1:10 a.m. on Friday, opens with a marginal risk for heavy rain into the weekend and localized flooding possible. Marginal is the lowest of the four categories the Weather Prediction Center uses for excessive rainfall.

The office expects two to four inch rainfall bullseyes each day, with locally higher amounts possible. It places the main flooding threat from the Sarasota and Bradenton area north to Levy County, and expects the heaviest totals near and along the coast.

On Southwest Florida the office is explicit. The threat could reach here because of the abundant deep layer moisture over the region, it writes, but it is not as high as for the northern and central parts of its forecast area.

Collier County falls under the Miami office. Its discussion, updated at 6:56 a.m. on Friday, reads the Weather Prediction Center outlook for Friday as keeping the marginal risk right along its own northern boundary. The counties it names for localized flooding under the heaviest downpours are Glades, northern Hendry and parts of northern Palm Beach. Collier is not among them.

The figure both offices are watching is atmospheric moisture. The Tampa Bay sounding taken at 8 p.m. on Thursday measured 2.34 inches of precipitable water, and the office expects that to persist through the weekend and into early next week. Miami has its own values returning to around two inches, alongside convective available potential energy in the range of 2,000 to 3,000 joules per kilogram.

Two mechanical details in the discussions carry more weight than the coverage percentages. Miami notes that pressure gradients relax on Friday and surface winds stay relatively light even in the afternoon, which it says increases the potential for localized flooding from slow moving or stationary storms.

The second is cumulative. Tampa Bay Ruskin writes that as daily rainfall totals mount, areas that receive the higher totals become increasingly at risk for flooding each following day.

For Saturday the Miami office puts rain chances at 30 to 50 percent south of Interstate 75 and 60 to 80 percent for northern areas, as a shift to southwesterly flow pushes more moisture across South Florida. Tampa Bay Ruskin expects a sharp upper trough to dig over the eastern United States over the weekend, with a frontal boundary crossing the southeast on Saturday and stalling over the Florida panhandle on Sunday.

Zach Maloch of WINK News, whose forecast published shortly before 5 a.m. on Friday, put Saturday coverage across Southwest Florida at 60 percent and described all of the region as under a risk for excessively heavy rainfall that day. He gave Friday at 30 percent coverage through the morning and 40 percent east of Interstate 75 in the afternoon, and Sunday at 20 percent rising to 50 percent by the afternoon. Those descriptions and the federal ones refer to the same marginal category.

Heat is the other product in play on Friday, and it does not cover Southwest Florida. The Miami office issued a heat advisory running from 11 a.m. to 6 p.m. for heat index values of 106 to 110 degrees, and the alert lists Palm Beach, Broward and Miami-Dade. The office gives a specific reason coastal Collier is outside it: breezier conditions there may help prevent advisory criteria from being met.

Highs across the region were forecast in the upper 80s to low 90s, with the Miami office allowing for upper 90s at some inland locations.