A weather brief for the Florida Keys of Monroe County concerning heavy rainfall potential throughout this week and the upcoming weekend is attached. The latest brief is also posted online at: https://www.weather.gov/media/key/DSS/dssbrief_land.pdf
Note that confidence in “where” and “when” will be low unless a better-defined surface weather feature were to evolve over the Florida Keys. For now, we are watching a weak, broad trough of low pressure to our northwest over the next couple of days, and a cold front forecast to approaching from the north, moving down the Florida Peninsula late this week.
Some of the ingredients are already in place. Deep, rich tropical moisture and an unstable, buoyant atmosphere supporting heavy downpours capable of temporary poor-drainage street, parking lot and area flooding form the primary weather threat this week for the Florida Keys this week.
Locally Heavy Rainfall Potential This Week
- Poor drainage street, parking lot and low lying area flooding is possible during and shortly after any heavy downpours.
- Those living and/or working in areas prone to frequent rainfall flooding should keep tuned for additional weather information throughout the week and this weekend.
- The risk for rainfall flooding will be highest during:
- Tuesday through Wednesday night time frame
- The hours of the higher high tide, generally around sunrise through the mid-morning hours
Potential Rainfall Amounts
- Total Rainfall over the next 3 days (through Thursday morning, Sep. 24th) is most likely to be in the 2.5 to 4.0 inch range, with a 10 percent chance of totalling in the 4.0 to 5.5 inch range.
- The chances for rainfall exceeding 2 inches each night and day (24-hours’ duration) are generally 10 to 25 percent through Wednesday, easing to 5 to 5 to 10 percent by Friday and Saturday, and may increase again for the period Saturday night through Sunday.
At this time, future briefings concerning and updating the heavy rainfall potential are planned to be issued around 9:30 am throughout this week.