textproduct: Columbia

WHAT HAS CHANGED

Updated Aviation.

KEY MESSAGES

- 1) A dry airmass settles over the region to round out the work week, leading to low-end fire weather concerns.

- 2) Much-needed rainfall still appears likely Saturday night through Monday.

DISCUSSION

KEY MESSAGE #1: A dry airmass settles over the region to round out the work week, leading to low-end fire weather concerns.

Behind a departing front, dewpoints are poised to drop significantly through the day. Values which were in the mid 50s Wednesday afternoon have already dropped by half or more in some locations early this morning, leading to relative humidities in the 25% to 35% range, particularly across the northern Midlands. Temperatures this afternoon are forecast to reach the upper 50s to low 60s across the area, which should eventually yield widespread relative humidities between 20% and 25%. This may lead to some isolated elevated fire weather concerns, but with northerly winds remaining overall weak at less than 10 mph, there isn't any additional support for fire weather statements or products today. Friday should also feature similar conditions, though temperatures and dewpoints may be a few degrees lower.

KEY MESSAGE #2: Much-needed rainfall still appears likely Saturday night through Monday.

A baja low is forecast to move through the Desert Southwest early in the upcoming weekend. Though some ridging ahead of this system will bring us some above normal temperatures initially, confidence continues to increase that we will eventually be impacted by this system. While the finer details are still coming into focus with this forecast package due to some timing and evolution discrepancies in the global models, NBM probabilities of >0.25" of 6-hr rainfall are 60% to 70% across almost the entire forecast area Sunday evening. In fact, the 48-hour rainfall probabilities of >0.75" are 70% to 90% ending 7 am Tuesday morning. Given these numbers, strong southwest flow through the column will bring PWAT values 200-225% percent of normal and very high chances for a wetting rain across the Midlands and CSRA. The latest thinking regarding timing appears to be with the best chances for heavier rain Sunday through Sunday night. Any chance at thunderstorms will depend on where the surface low tracks and how strong the preceding surface high pressure system is. Given that much of the area remains entrenched in moderate to severe drought, things may be looking up for the area to receive some much-needed rainfall late this weekend into early next week.

AVIATION /12Z THURSDAY THROUGH MONDAY/

VFR Conditions Likely Through the TAF Period.

Dry high pressure builds into the region and will bring VFR conditions to all taf locations over the next 24 hours. Winds will become more light and variable through the day and into tonight. Only clouds expected will be some thin cirrus tracking over the region, with skies expected to remain mostly clear through the period. Fog is not expected..

EXTENDED AVIATION OUTLOOK...Restrictions are possible this weekend with another system moving into the area.

CAE WATCHES/WARNINGS/ADVISORIES

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