8/9 – Rob Knight’s “Heavy Rain Threat” Tuesday Morning Forecast
In a near carbon copy of last week, rain chances will once again continue to be high through the period. High pressure over the western Atlantic will keep the area in a period of onshore flow. In addition, a tropical wave will be moving slowly across the north-central Gulf of Mexico today and tomorrow. The combination of those features will allow tropical moisture to stream into the area, supporting high precipitation chances and the possibility that some of the showers and thunderstorms could be extremely efficient rainfall producers. Steering currents are fairly weak as well, increasing the possibility of heavy rainfall across the area.
Much of the same is expected tomorrow and Thursday as the heavy rain potential will only increase. Given the rather high rainfall amounts over the past few weeks along with the expected rainfall today and tomorrow, some additional concern is warranted for tomorrow and Thursday. Deep moisture will still be entrenched across the region allowing for areas of heavy rain once again. Training bands of rain along with merging cells could bring hourly rainfall rates as high as 3 inches. Due to this possibility, most of the area has been out looked for a slight risk for excessive rainfall tomorrow and into Thursday morning and may need to be expanded in time. A Flash Flood watch may be warranted later in the week but opted to hold off for now to see the coverage and amounts that occur today.
In addition to the rainfall concerns, a coastal flood advisory is also in effect through midday Thursday due to the persistent onshore flow. This is mainly for issues that may develop during the normal high tide periods.
No significant changes made to the long term portion of the forecast. Persistent ridging over the central Rockies will slide slightly east and south by the end of the week. This will place our area on the eastern periphery bringing a period of northerly flow into the area. Due to this, the focus for the shower and thunderstorm activity over the weekend will shift from a heavy rainfall threat to more strong storms with wind gust potential.