textproduct: Columbia

WHAT HAS CHANGED

Updated Aviation Discussion for 18Z TAFs.

KEY MESSAGES

- 1. Above normal temps expected through Monday, with a backdoor front ushering in drier and slightly cooler air through the middle of next week.

DISCUSSION

KEY MESSAGE 1: Above normal temps expected through Monday, with a backdoor front ushering in drier and slightly cooler air through the middle of next week.

Not much change in the forecast thinking, with Sunday being a transition day aloft as broad mid-level trough shifts east and ridging will steadily build into Monday. The pattern will then steadily amplify as persistent troughing across the western CONUS will yield strong downstream height rises across the southeastern CONUS, resulting in one of the stronger 500 hPa ridges on record for this time of year based on the NAEFS climo. While this would typically suggest potentially record high temps, a stout shortwave is expected to round the ridge into the northeastern CONUS Monday, with associated strong convergence. This convergence is forecast to usher in a strong surface high pressure system into the Northeast, driving ridging lee of the Appalachians through mid-week. As this ridging digs southward it will manifest as backdoor surface front will some denser, cooler & drier air pushing in from the northeast and bringing near normal highs & below normal dewpoints and PWs by Tuesday. Ahead of this backdoor front however, Monday will be quite warm, with highs forecast in the mid 90s. But Tuesday-Thursday should feature highs in the upper 80s to lower 90s, dewpoints in the low 60s during the afternoons or upper 50's, and overnight lows in the mid 60s. Southerly component flow and broad scale moisture returns by late week with increased precip chances along with it.

AVIATION /16Z SUNDAY THROUGH THURSDAY/

VFR conditions are expected through the TAF period.

FEW to SCT cumulus are developing this afternoon with westerly winds around 5-8 kts. VFR conditions likely continue through the remainder of the day where a spotty shower cannot be ruled out near AGS/DNL, but impacts are unlikely. Overnight, a few passing cirrus could be seen as light and variable to calm winds develop. Slightly drier air is expected to push in, bringing lower chances for morning restrictions, as seen in the latest HREF, HRRR, and LAMP guidance. Cannot rule out a few patches of fog or stratus early Monday morning mainly in portions of the CSRA and southeastern Midlands, but confidence in impacts to the TAF sites is fairly low. Winds Monday morning shift a bit more northerly to northeasterly as VFR conditions likely continue through the end of the TAF period.

EXTENDED AVIATION OUTLOOK...Rain unlikely for much of the week but there will still be some potential for early morning fog/stratus persists at least through Tuesday.

CAE WATCHES/WARNINGS/ADVISORIES

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