textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 06Z forecast.

KEY MESSAGES

- 1. Scattered showers possible later tonight into early Sunday with more widespread rain chances Monday. Potential totals continue to trend down.

DISCUSSION

Key Message 1: Scattered showers possible later tonight into early Sunday with more widespread rain chances Monday. Potential totals continue to trend down.

A relatively unsettled patterns continues through Monday as deep troughing lingers over the eastern US and interacts with a reservoir of gulf moisture. However, the majority of the heavier showers and persistent rain chances are staying to our south as a series of strong convective systems have cut off some of the moisture advection. Model guidance continues to suggest the best rain chances tonight will be across the far southern CSRA into the southeastern Midlands, roughly from Burke to Clarendon counties. Even here, rainfall amounts are forecast to be under a tenth of an inch. General instability and high PWAT's could still pop scattered showers or an isolated thunderstorm Sunday afternoon, especially along and south of I-20, but overall a dry Mother's Day with clearing skies and warmer temperatures is favored.

More widespread showers and storms are expected Monday as a strong shortwave and associated surface front push through, but the potential for notable accumulations has trended down. LREF clusters and overall ensemble guidance has backed off considerably on potential totals from this slowing front for much of the area; generally 0.5-1.0" likely along I-95 and south of I-20, less than 0.25" expected to the north of I-20. Overall the down trend in totals is due to some offshore low pressure development and stronger convection to our south. These both prevent the strongest moisture advection and higher PWAT's from pushing into SC. So the best chances for heavier precip will be focused in the afternoon, closer to the coast and in the southern CSRA. Drier air fills in late Monday and Tuesday with another front moving through on Wednesday.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

VFR conditions generally expected through the 24hr TAF forecast period outside of some brief restrictions this morning.

high clouds continue to stream over the forecast area this morning as an upper trough approaches from the west. The combination of low level moisture and noctural cooling has resulted in some IFR/LIFR restrictions in fog/stratus. As the shortwave passes any restrictions should improve and return to VFR by 14z but will include tempo groups for restrictions to start the forecast. Light winds 5 knots or less expected into mid morning before winds pick up a bit from the west to around 5 to 8 knots through the afternoon.

EXTENDED AVIATION OUTLOOK...Another system brings a chance for restrictions with widely scattered showers and thunderstorms Sunday Night and into Monday. Conditions will improve Tuesday with mainly VFR expected. Another front with more scattered showers and thunderstorms will approach the terminals later Wednesday.

CAE WATCHES/WARNINGS/ADVISORIES

SC...None. GA...None.