textproduct: Columbia

SYNOPSIS

A much colder air mass builds in behind an exiting cold front, with below normal temperatures and continued breezy conditions. Near to below normal temperatures will then prevail through much of next week. The chance of rain during the next seven days is low, less than 20 percent.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Lake Wind Advisory continues this afternoon and evening. - Gusty conditions with much colder conditions. - Increased fire danger with low RH and gusty winds

This afternoon: Strong winds will continue across the region, with additional wind gusts of over 30 mph being quite common, and even 40 mph gusts not completely out of the question. Lake wind advisory remains in effect. Strong cold advection will be taking hold, bringing much cooler conditions to the region. This will be offset slightly by the amount of sunshine and some downsloping through the afternoon.

Tonight: The strong cold advection continues tonight. Very dry high pressure will be moving into the forecast area. Winds will diminish after sunset, and go light and variable towards midnight. The almost completely decoupled airmass towards morning will combine with the dry air and clear skies to bring very cold temperatures. Lows expected to dip down into the mid to upper 20s with strong radiational cooling.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Key message(s):

- Cool, high pressure builds in Monday through Tuesday night.

Following the cold, dry advection on Sunday, high pressure will quickly fill in for the first half of the week with strong northwesterly flow aloft. Temps will run a bit below average as a result for both overnight lows and daytime highs especially on Monday. Winds will be light as the surface high moves overhead and no precip is expected through Tuesday.

LONG TERM /THURSDAY THROUGH SUNDAY/

Key message(s):

- A series of sharp troughs will dig across the area Wednesday and then again over the weekend.

Like we saw on Sunday, the current synoptic pattern of mostly dry fronts and trough passages every 3-4 days will continue; this pattern is broadly driven by the decaying pacific jet positioning and consequent downstream ridging in the western US. So a quickly strengthening trough will dig across the central US and drive a surface low and front over our area Wednesday. While the trough and height falls will be notable, moisture advection ahead of the front is not very impressive. So precip chances increase Wednesday and early Thursday, but only ~20-30% for the area. Behind the front on Thursday, strong gusty winds are expected and could be close to wind advisory criteria with some gusts over 40 mph. This 3-4 day synoptic pattern will then continue with a relaxing trough Friday into Saturday and then another digging shortwave on Sunday with increasing rain chances.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

VFR conditions prevail through the period.

With the very dry airmass moving into the region, no restrictions are expected through the period. Biggest issue into early evening is going to continue to be the winds across the region. Winds will be westerly this afternoon, with sustained speeds between 15-20 knots, and wind gusts around 30 knots possible. Stronger winds will remain off the surface, but not close to any llws due to the strength of the surface winds. Towards sunset, winds at both the surface and below 2kft will begin to weaken, with surface winds dropping to around 10 knots around 00z, then closer to light and variable towards 05z. Once again with lower level winds all diminishing, llws will not be an issue. Light and variable winds and vfr conditions will prevail on Monday at all sites.

EXTENDED AVIATION OUTLOOK...A mid-week system moving through could bring brief restrictions.

FIRE WEATHER

Fire weather concerns remain elevated this afternoon and early evening due drying and RH values dropping to near critical values, along with strong wind gusts over 30 mph with deep mixing. We have issued a Fire Danger Statement for our entire forecast area through this afternoon and early evening. In addition, the SC Forestry Commission has issued a Red Flag Fire Alert for increased fire danger discouraging burning from the Midlands to the coast.

Another strong front is expected mid-week, so depending on precip amounts, another round of fire danger concerns may occur again Thursday.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory until 7 PM EST this evening for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. GA...Lake Wind Advisory until 7 PM EST this evening for GAZ040- 063>065-077.