textproduct: Columbia

WHAT HAS CHANGED

Updated key messages to highlight the heat expected by the end of the week into early next week. Aviation discussion updated for 06z TAFs.

KEY MESSAGES

- 1. Heat builds with strengthening upper ridging late this week. Above average temperatures expected Friday through early next week.

DISCUSSION

Key Message 1: Heat builds with strengthening upper ridging late this week. Above average temperatures expected Friday through early next week.

Heat indices will be lower today as low level dry air filters into the area behind a cold front. This will be the most comfortable day of the period as heat is expected to build late this week into the weekend. Strong model consensus in heights rising beginning Thursday. NAEFS mean indicates 500mb heights by Friday will be above the 90th percentile and will remain above the 90th percentile through early next week as ridging strengthens to the west of the forecast area. EC EFI shows max T over the area near 0.8 for each day Friday through Sunday, although not a significant shift of tails signal, indicating the potential for unusually high temperatures this weekend but not expecting extreme heat. A bit more uncertainty in blended guidance temperatures into early next week with some potential weaknesses in the ridge as the pattern becomes more amplified with lowering heights expected across New England and rising heights over the Great Lakes, leaving the Southeast somewhat in between. In general, however, blended guidance supports the hottest period of the year so far to close out the month of June with heat indices potentially exceeding 100F each day, although at this point expected to remain below Heat Advisory criteria.

Ensemble means indicate near normal PWATs Friday into the weekend, although the ridging in place will likely support broad subsidence over the forecast area. A weakening shortwave Friday may support scattered showers or storms but otherwise expect isolated diurnally driven convection. The precip potential will likely be highest in the northeastern portion of the forecast area this weekend into early next week where there will be potential weaknesses in the ridge.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

VFR conditions expected through the TAF period.

The frontal boundary continues to shift southward through the FA tonight, with light winds becoming increasingly northerly. FEW to SCT mid level clouds are associated with this frontal passage, but outside of this, VFR conditions should persist into the morning hours as drier air pushes in. 6-9 kt winds turn a bit more northeasterly late this morning and into the afternoon as FEW cumulus develop after 16-18z with passing cirrus. Winds then are expected to become light and variable this evening and toward the end of the TAF period with mostly to partly clear skies.

EXTENDED AVIATION OUTLOOK...Increasing heat and humidity starting Thursday into the weekend should yield daily diurnal convection and possible associated restrictions.

CAE WATCHES/WARNINGS/ADVISORIES

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