textproduct: Columbia

WHAT HAS CHANGED

Key Message 1 update and Aviation discussion for 00z TAF.

KEY MESSAGES

- 1) Mainly dry weather on Saturday as the next storm system approaches from the west.

- 2) Beneficial rainfall still appears likely late Saturday night through Monday. Guidance remains consistent with a general 0.5"-1.0" across the area, and the potential for higher totals across the northern Midlands.

DISCUSSION

KEY MESSAGE #1: Mainly dry weather on Saturday as the next storm system approaches from the west.

High pressure will be overhead at the start of the day, moving offshore as the next storm system approaches from the west. Winds on Saturday will be generally out of the northeast and likely higher than today, with gusts of 10-15 mph possible during the daytime hours. Afternoon RH values will fall into the 20 to 30 percent range for most locations so caution should be used if burning tomorrow. Clouds increase through the day ahead of the next storm system but rain should hold off until Saturday night at the earliest.

KEY MESSAGE #2: Beneficial rainfall still appears likely late Saturday night through Monday. Guidance remains consistent with a general 0.5"-1.0" across the area, and the potential for higher totals across the northern Midlands.

The forecast remains on track for our soaking rainfall on Sunday. Guidance is in good agreement in timing and location of the mid-level low, ejecting from the Baja region today and tomorrow, and the associated surface low. Overall, guidance is slightly slower with the progression of all of this but that really doesn't impact the overall forecast. LREF clusters are in good agreement that 0.5-1.0" of rainfall is expected with this system. The highest totals are likely to be in the northern Midlands, generally north of I-20, where the warm front lifts to and adds a bit of extra forcing/focus for rainfall on Sunday evening. Some thunder is possible with the rain as convection to our west develops, moves eastward, and weakens over the area Sunday evening. These heavier rain showers could enhance overall precip rates and allow other areas to approach the 1" mark. But overall, a good expectation is around 0.5" for most, which will be nice and beneficial. By next week, a major warm up is on tap with LREF guidance suggesting 90th percentile 500 hPa heights and at least 98th percentile 850 hPa temps overspreading the area by the middle of next week.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

VFR conditions expected through the 24 hr TAF period.

High pressure will continue to settle over the area tonight into Saturday. Winds have become light and variable to calm and should remain so through Saturday morning before winds pick up from the south around 5 knots after 16z. Some increase in higher clouds expected after 12z and may lower towards the end of the forecast period but VFR cigs expected to prevail.

EXTENDED AVIATION OUTLOOK...Restrictions continue to look most likely Saturday night through Sunday with the next system moving in, bringing widespread rain chances.

CAE WATCHES/WARNINGS/ADVISORIES

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