textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 00z TAF issuance.

KEY MESSAGES

- 1. Generally dry weather and well above normal temperatures expected with heat index values over 100F this week.

- 2. Active weather and decreasing temperatures possible this weekend.

DISCUSSION

KEY MESSAGE 1. Generally dry weather and well above normal temperatures expected with heat index values over 100F this week.

Any spotty shower activity has diminished this evening with dry conditions likely persisting overnight tonight with low temperatures in the low to mid 70s.

A mid- to upper-level ridge will continue to build eastward through the week becoming centered over the southeast by Thursday. Both deterministic and ensemble guidance remain in good agreement on this evolution. NAEFS guidance indicates 500-mb heights will approach the climatological max into Thursday before decreasing slightly toward the weekend. With the ridge moving more overhead, generally dry conditions are expected to persist the rest of the week. The main concern remains to be the heat, with temperatures reaching the upper 90 each day. In addition, the increased humidity will result in heat index values exceeding 100F during the afternoons through the remainder of the week. There is potential for conditions to approach Heat Advisory criteria late in the week, though this will depend largely on how well the atmosphere mixes each day. Regardless, heat-related illnesses will remain possible.

KEY MESSAGE 2. Active weather and decreasing temperatures possible this weekend.

Global ensemble guidance still suggests the ridge will retrograde westward, allowing a trough to dig southward along the East Coast. As this occurs, chances for showers and storms are expected to increase as we head into the weekend ahead of an approaching cold front. Cooler afternoon temperatures and drier air are also anticipated behind the front.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

VFR conditions generally expected outside of possible predawn fog at favored locations.

Upper ridge continues to build eastward toward the Carolinas and should support generally dry and hot conditions. Cumulus has generally dissipated after sunset and skies will be mostly clear overnight. Possible MVFR/IFR vsbys at fog prone AGS/OGB during the 08-12z time frame so included a tempo for this possibility otherwise confidence too low at other terminals to include in the forecast. Overall, fog appears less likely Wednesday morning compared to this past morning (which was patchy). Winds generally out of the southeast Wednesday, although remaining relatively light, around 5kts.

EXTENDED AVIATION OUTLOOK...Early morning restrictions still possible despite a drier outlook for the week. Increased chances of restrictions over the weekend with increased chances of convection with an approaching cold front.

CAE WATCHES/WARNINGS/ADVISORIES

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