textproduct: Columbia

WHAT HAS CHANGED

Confidence increasing in the overall synoptic pattern through much of the week. Potential for a stronger system this weekend leading to higher rainfall amounts. Updates to aviation section.

KEY MESSAGES

- 1) Warming trend through mid-week, then near to slightly below normal temperatures Thursday into the weekend.

- 2) Rain chances increase Wednesday. Additional chances for rain late week into next weekend.

DISCUSSION

KEY MESSAGE #1: Warming trend through mid-week, then near to slightly below normal temperatures Thursday into the weekend.

Upper ridging building over the central US with surface high pressure shifting offshore will favor temperatures continuing to warm into the middle of this week. Highs today will be near average, rising to above average Tuesday and Wednesday with highs likely in the 70s for much of the area Tuesday (a bit cooler Wednesday with chances for rain). With higher confidence in the front shifting south of the area into Thursday, there is less of a spread in high temperatures through the end of the week within blended guidance. Air mass behind the front not expected to be particularly cold with temperatures near to slightly below average through the end of the week. A bit more uncertainty into the weekend as with a strengthening low developing to the west and moving towards the area (more on this in key message 2).

KEY MESSAGE #2: Rain chances increase Wednesday. Additional chances for rain late week into next weekend.

An upper low near Baja California currently will begin to push eastward into the Southern Plains by mid-week, pulling moisture into the central CONUS. Another upper low moving into the Northeast will lead to deepening surface low pressure as a front extends southwest, expected to move into the forecast area. While forcing will generally be weak over the area, NAEFS mean indicates IVT over the 90th percentile with a relatively rapid moisture increase expected Wednesday. This will lead to increasing chances for rain, although generally low QPF. Blended guidance indicates low probabilities (less than 30 percent) of total rainfall greater than a quarter inch. Guidance has continued to trend towards the front dropping south of the area with surface high pressure shifting into the Great Lakes. Global models and ensembles are generally on board with a dry Thursday with less than 10 percent of EC and GEFS members showing measurable rain Thursday into Thursday night. Additional disturbance likely moves into the area Friday although uncertainty as to the amount of moisture increase. A stronger upper shortwave near the Four Corners region will lead to a strengthening developing in the central US which would likely lead to more substantial chances for rain for the weekend, although there remains uncertainty into the progression of the system as it traverses the country.

AVIATION /06Z MONDAY THROUGH FRIDAY/

VFR conditions continue.

Mainly expecting some mid and upper level cloudiness to pass across the forecast area through the taf period. Winds are forecast to remain light, generally 5 kts or less, through the TAF period, becoming predominantly southeast after daybreak and transition to southerly late in the period.

EXTENDED AVIATION OUTLOOK...No anticipated aviation concerns through early this week. Restrictions possible moving into mid-week as another system pushes into the region and brings rain potential along with it.

CAE WATCHES/WARNINGS/ADVISORIES

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