textproduct: Columbia

WHAT HAS CHANGED

Updated discussion for key messages; overall the forecast is on track over the next 7 days.

KEY MESSAGES

- 1. Beyond today, a more summer-like pattern is expected through Wednesday. Dry weather arrives for the end of the workweek.

DISCUSSION

- 1. Beyond today, a more summer-like pattern is expected through Wednesday. Dry weather arrives for the end of the workweek.

The entirety of this forecast period is expected to be dictated by an intense and anomalous ridge of high pressure across the western CONUS. This is currently anchored across the central Rockies and guidance is in good agreement showing it slowly retrograding westward through the week. As it does so, deep and anomalous 500 hPa troughing is forecast to settle across the eastern CONUS, with multiple shortwaves (especially between today and Wednesday) passing southeastward in the flow. This is forecast to begin today, with a round of isolated to scattered showers/storms this afternoon as a shortwave passes atop our remnant stalled frontal boundary. Heavy rainfall is the primary threat with any of this activity.

As we get into the work week, guidance suggests that moisture will briefly decrease on Monday, resulting in lower rain chances. By Tuesday and Wednesday, though, another shortwave is forecast to push southeastward towards the base of the mid/upper level trough. Guidance is in good agreement that this will force a surface low to develop along the lee side of the Appalachians, driving a cold front towards the area that is progged to pass through on Wednesday night. The dip in PWs on Monday will be brief as warm advection is forecast to bring 1.7"-1.9" PWs back into the area ahead of the shortwave and associated surface front on Tues/Wed. Some of the ML guidance has been suggesting that the area will see a severe weather threat on both Tuesday and Wednesday within this regime. While it isn't out of the question (especially in the Pee Dee Region on Tuesday evening), it seems unlikely that the area will see severe weather. The better forcing and wind shear should remain to our north where SPC has outlined a Slight Risk for storms on D3.

The orientation of the trough also makes it tough for us to see widespread convection as we'll be pretty firmly beneath the right exit region of the jet streak that will help reinforce the trough. Given shortwaves within the general flow and an approaching front, expect isolated to widely scattered showers/storms on Tuesday afternoon and again early Wednesday afternoon. But for those hoping for any good rain, it looks few and far between with the way the upper level setup looks midweek unfortunately. What is fortunate: some drier air is forecast to push into the region behind the front Wednesday afternoon through Friday. Temps throughout the week look near normal, with the exception of Tuesday where upper 90s are expected. The drier air towards the end of the week, driven by the deep upper trough, should provide some respite from the overall intense heat/humidity. Guidance struggles with what will happen with the trough by the end of next week as the ridge to our west continues to slowly retrograde westward. This adds considerable uncertainty to the forecast beyond Friday.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Restrictions likely early this morning, returning to VFR after 18Z.

Abundant low level moisture over the area and a weak surface boundary will once again favor ceiling restrictions early this morning. MVFR ceilings are most likely between 09Z and 15Z but IFR ceilings will also be possible closer to sunrise. MVFR ceilings could linger into the late morning or early afternoon but guidance has been persistent in clearing out ceilings after 18Z.

Expect isolated to scattered showers and thunderstorms today as shortwaves stream over the region helping to promote storms even outside of the diurnal norm. That said, convective activity should peak in the afternoon today, particularly in the eastern Midlands including 0GB. Winds will be variable for much of the day with the weak boundary wavering across the TAF sites.

EXTENDED AVIATION OUTLOOK...Restrictions unlikely early this coming week. By late Tuesday and into Wednesday, rain chances begin to increase again with associated restrictions possible.

CAE WATCHES/WARNINGS/ADVISORIES

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