textproduct: Columbia

WHAT HAS CHANGED

Rain and storms are slowly moving into the western portions of the forecast area. Breezy with another round of showers and storms expected this afternoon. Warm temps continue with record highs possible midweek. Aviation discussion updated for 06Z TAFs.

KEY MESSAGES

- 1. Scattered showers and a few thunderstorms likely early this morning.

- 2. A few strong storms are possible this afternoon and evening followed by some diurnal shower activity through midweek. - 3. Temperatures continue to be well above normal through midweek week.

DISCUSSION

KEY MESSAGE #1: Scattered showers and a few thunderstorms likely early this morning.

A line of showers with a few embedded thunderstorms is just moving into the western portions of the forecast area early this morning. As this activity continues to inch eastward, it is anticipated to weaken and generally dissipate by daybreak. Latest radar trends are already showing signs of weakening, so there is some question of how far east these showers get. The most likely scenario is that rain stays north and west of the I-20 corridor, but some isolated showers may reach beyond that.

KEY MESSAGE #2: A few strong storms are possible this afternoon and evening followed by some diurnal shower activity through midweek.

A mid level trough currently over the Plains is expected to progress eastward through the day. As it does, an associated frontal boundary is forecast to move through the area today, becoming diffuse at it does. Ahead of this boundary, expect breezy southwest winds, but should generally stay below Lake Wind Advisory criteria. As the boundary passes, there should be enough forcing to produce another round of showers and storms. While CAPE values are forecast to be marginal (500-1000 J/kg) with this activity, 0-6 km shear values are expected to be sufficient in the 30-40 kt range to support a strong to marginally severe storm, mainly close to the North Carolina border. Thus, SPC has a Marginal Risk for storms for today. Satellite imagery shows a stratus deck is beginning to develop in the eastern Midlands, so the amount of instability we see today is somewhat reliant on how widespread the stratus gets and how quickly it can bur off. Once this activity passes, the anticipated heat through midweek brings chances for diurnally driven showers for Monday and Tuesday ahead of a cold front moving into the region for midweek.

KEY MESSAGE #3: Temperatures continue to be well above normal through midweek week.

The aforementioned trough is starting to flatten the ridge overhead, and is expected to continue doing so through the day. Despite that, temperatures are forecast to be well above average today and Monday. A closed low over the Baja California is forecast to eventually eject eastward during the week, strengthening the ridge over the Southeast. This is expected to push temperatures even higher for midweek. Both the NAEFS and ECMWF EFI show that temperatures on Wednesday are at the top of the climatological chart for this time of year. Meanwhile, the NBM 75th percentile is 89F at both CAE and AGS on Wednesday. This gives us a decent shot at the record high temp at both sites, which happens to be 88F at each location. Temperatures are then expected to drop to near average, which will likely feel chilly given the long stretch of such warm weather.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

MVFR/IFR stratus expected to redevelop and bring periodic restrictions this morning. A few showers expected during the predawn hours and again this afternoon.

Radar imagery continues to show a weakening line of showers with embedded thunderstorms approaching the forecast area from the west. However, most hi-res model guidance indicates this line will dissipate over the next hour or two, with only a few showers reaching the terminals. It is possible however, that a brief period of rain will occur sometime in the 08-12z timeframe this morning. Otherwise, the environment remains generally unchanged with moist southerly flow ahead of the approaching front. Guidance continues to support additional stratus development this morning, favoring the eastern Midlands and generally remaining MVFR with brief IFR conditions. Stratus should scatter out and lift by mid morning (14z- 15z) and a VFR ceiling is then expected through the day as the front moves into the area and becomes diffuse. Scattered showers and thunderstorms are possible after 17z but confidence in impacts at terminals is limited, so included a PROB30 group with this issuance. Additional stratus and fog restrictions will be possible again tonight behind the frontal passage. Surface winds should remain southerly to southwesterly today, with a few gusts this afternoon to around 20 kts. Additional gustiness is possible in and around stronger -TSRA/-SHRA.

EXTENDED AVIATION OUTLOOK...Patchy morning fog remains possible each day. Increased shower and storm chances expected into early next week.

CAE WATCHES/WARNINGS/ADVISORIES

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