textproduct: Columbia

WHAT HAS CHANGED

Rain chances have increased some for Friday, but totals continue to look light. Aviation discussion updated for 06z 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 /06Z TUESDAY THROUGH SATURDAY/

VFR conditions should prevail through most of the TAF period except for possible brief MVFR cigs this morning.

Mostly clear skies at the terminals this morning. Low level easterly flow continues to bring moisture into the region, and satellite imagery shows low clouds moving onshore. These clouds may make it to the terminals over the next few hours, and there may be a period of restrictions given cloud bases between 2-4kft MSL. MOS, LAMP and NBM guidance are all showing this potential generally between 09z and 15z this morning depending on which terminal. Have covered this with TEMPO groups for now, but will continue to monitor trends over the next several hours. Otherwise, VFR will prevail through today into this evening. Early guidance does show potential for another round of CIG and VSBY restrictions possible tonight, but will reassess with later TAF issuances. 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. Decoupling is then expected this evening with speeds dropping below 5 kts at CAE/CUB/OGB, but possibly remaining elevated elsewhere.

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.