textproduct: Columbia

WHAT HAS CHANGED

Rain chances have increased some for Friday, but totals continue to look light. Aviation discussion updated for 12z TAF issuance.

KEY MESSAGES

- 1. Light rainfall amounts possible late this week.

DISCUSSION

Key Message 1: Light rainfall amounts possible late this week.

An upper low and associated deep trough currently over the southern Plains are expected to slide east through midweek. A trailing frontal boundary approaches the Southeast, As the system approaches, the main energy is forecast to lift northward, limiting moisture advection to the area initially. The frontal boundary also looks to slow down some, keeping most of the rain to our west as we head into Wednesday and Thursday. A secondary upper trough is forecast translate across the continent, which is forecast to help push the front through the area at the end of the week. Latest guidance continues to show a relatively slow progression, but better moisture transport can be expected. Therefore, rain chances have increased some for the end of the week. However, despite the increased rain chances, the best lift remains north of the area, so amounts continue to look relatively light. The ECMWF and GFS both show low chances (10-25%) of 24-hour amounts of greater than 0.50" on Friday. After this system pushes through, drier air is forecast to move back into the area once again.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Brief MVFR CIGS possible this morning with VFR then prevailing through this evening. Another round of restrictions is possible late tonight into early Wednesday morning.

Low level easterly flow continues to bring moisture into the region, with satellite imagery showing the development of SCT- BKN stratus across the region. Cloud bases are generally between 2-4kft MSL, and brief MVFR CIG restrictions are being noted at a few locations. Have covered this with TEMPO groups for now, generally ending around 14z-15z when clouds bases should start to increase back to VFR for the remainder of today. Surface winds should remain around 3 to 6 knots from the east-northeast this morning before picking up to around 7 to 10 knots from the east after 15z. Winds should weaken this evening with speeds dropping below 5 kts at CAE/CUB/OGB, but possibly remaining elevated at AGS/DNL/AIK. Looking ahead to tonight, guidance continues to indicate potential for another round of CIG and VSBY restrictions, potentially into the IFR range.

EXTENDED AVIATION OUTLOOK...Increasing chances for rain during the mid to late week may lead to some lower CIGS or VSBY restrictions.

CAE WATCHES/WARNINGS/ADVISORIES

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