textproduct: Columbia

WHAT HAS CHANGED

Confidence continues to be high in well above average temperatures for the second half of the week into the weekend. Aviation discussion updated for 12z TAFs.

KEY MESSAGES

- 1. Well above normal temperatures with showers and isolated thunderstorms possible later this week.

DISCUSSION

KEY MESSAGE #1: Well above normal temperatures with showers and isolated thunderstorms possible later this week.

Surface high pressure near New England is currently shifting offshore with upper ridging expected to begin to strengthen over the forecast area today. This strengthening ridging will lead to rising temperatures to well above average by late week into the weekend. The NAEFS mean indicates that 500mb heights will rise to above the 97th percentile with models consistent in strong upper ridging over the eastern CONUS. EC EFI highlights Friday through Sunday above 0.8 for max temperatures indicating persistent unusually warm period for the weekend. Confidence remains high in the temperature forecast with limited interquartile range for NBM with highs generally in the low to mid 80s by the end of the weekend and into the weekend, with relatively high confidence continuing into early next week.

Moisture will generally increase as well with increasing southwesterly flow aloft, although the building upper ridge will likely preclude widespread precipitation until the ridge begins to break down somewhat, which models indicate likely won't be until late in the weekend. With LREF PWAT probs greater than an inch around 60-70%, there will be potential for diurnal showers and an isolated storm Friday into the weekend, with pops generally increasing each day.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

MVFR, or even brief ifr ceiling restrictions, will continue into early this afternoon, then improvement by late afternoon. Fog development possible early Wednesday morning.

Satellite continues to show widespread stratus deck across the region, with metar observations indicating mvfr ceilings. Ifr ceilings shown down across the far eastern Midlands and coastal plains of SC/GA. Guidance remains bullish on keeping low end mvfr, with brief periods of upper end ifr possible, through about 18z, then indications that ceilings will begin to lift into upper end mvfr and begin to break out. Vfr conditions should occur by late afternoon with better mixing. Vfr should then prevail for much of the early overnight hours before visibilities start to drop to ifr/lifr as fog begins to form around 09z. Winds out of the northeast to east overnight and through the day, then becoming more light and variable towards the end of the period.

EXTENDED AVIATION OUTLOOK...There is potential for morning stratus or fog into the latter half of the week along with increased shower chances for the weekend.

CAE WATCHES/WARNINGS/ADVISORIES

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