textproduct: Columbia

WHAT HAS CHANGED

Changed wording to reflect current conditions. Aviation discussion updated for 00z TAFs.

KEY MESSAGES

- 1. Chances for showers and storms continue each day this week as temperatures hover around average. A couple strong to marginally severe storms possible Tuesday.

DISCUSSION

- 1. Chances for showers and storms continue each day this week as temperatures hover around average. A couple strong to marginally severe storms possible Tuesday.

Forcing from the trough is bringing isolated convection across the northern and central Midlands. Showers/storms are expected to diminish shortly after sunset, with the main risk being locally heavy rainfall and possibly isolated instances of flash flooding if training occurs.

The mid level low is progged to meander through northern GA toward the southern part of the Blue Ridge Mountains the next couple of day's with wrap around moisture working back into the FA, though some mid level dry air is expected to remain in place, especially Tuesday. Cooling mid level temperatures/steepening mid level lapse rates Tuesday should bring solid CAPE profiles with near 2000-2500 J/kg of SBCAPE developing as effective shear nears 20-30 kts. Generous BL mixing is also expected to yield DCAPE around 800-1200 J/kg. Overall, forcing from the low in this environment is expected to bring more scattered convection during the afternoon and into the evening Tuesday where an isolated strong to marginally severe storm could be possible, bringing the risk of damaging downburst wind gusts. Wednesday is expected to be set up fairly similar as the low remains in the region, but the risk for stronger storms seems a bit lower. Ensemble guidance is in fairly good agreement that the mid level low will slowly be picked up in the synoptic flow as a robust ridge near the NAEFS climatological max builds off the East Coast. The ridge should allow deep southerly to southwesterly flow to persist late in the week and into this weekend, keeping PWAT's during this period near 2" with seasonable temperatures and diurnally driven chances for showers/storms each day.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

IFR or lower restrictions likely again overnight.

The overall pattern remains little changed since yesterday prompting a persistence forecast for the TAF sites during the next 24 hours.

Light winds and abundant low level moisture overnight and early Tuesday will allow for widespread stratus development, potentially building down to reduce visibilities. Models have been persistent indicating IFR restrictions from around 06Z to an hour or so after sunrise. Given that this verified well for the previous day we have introduced IFR ceilings at all TAF sites with LIFR cigs/vis in a TEMPO group for a few hours around sunrise.

Light south or southeast winds are expected through the day Tuesday. With weak moisture convergence over the area, we expected another day of scattered showers and thunderstorms. Coverage should support PROB30 groups for thunderstorms on Tuesday afternoon, similar to the previous day.

EXTENDED AVIATION OUTLOOK...Diurnal thunderstorms expected this week with early morning restrictions likely.

CAE WATCHES/WARNINGS/ADVISORIES

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