textproduct: Raleigh

WHAT HAS CHANGED

* Some patchy frost may be possible Tuesday morning, though a better chance of widespread frost/freeze is expected next weekend.

KEY MESSAGES

As of 1215 AM Sunday...

1) Rain chances and amounts are still highly uncertain late this week. Below normal temperatures and the potential for widespread frost/freeze is expected next weekend.

DISCUSSION

As of 1215 AM Sunday...

KEY MESSAGE 1... Rain chances and amounts are still highly uncertain late this week. Below normal temperatures and the potential for widespread frost/freeze is expected next weekend.

After a chilly start this morning under cool high pressure, temperatures should climb into the 60s this afternoon as return flow sets in and high clouds move east. A warming trend with temperatures some 5-10 degrees above average will take shape this upcoming week as low-level thicknesses rise and periods of return southwest flow remain in place. Some patchy frost could occur Tuesday morning under a night of clear skies and light winds. A mid-level disturbance crosses the region Wednesday, which could increase clouds but offer limited rain chances as Gulf moisture is essentially closed off.

We continue to watch a late-week storm system that is poised to develop as an Omega block sets up with ridging across the western US and troughing in the eastern US. A dip in the polar jet stream occurs across the east, phasing with the subtropical jet, leading to downstream cyclogenesis. The aggregate of ensemble members, including AI guidance, shows a surface low track across the northern Mid-Atlantic states Thursday into Friday. However, there are still some outlier solutions which track the low further south across the TN valley or even over the Carolinas. The further south solutions would offer a better chance of accumulated rainfall along the deformation band, while the northern consensus trend would bring isolated rain amounts. The best chance with this scenario would be along the cold front Thursday afternoon or evening, which if it trends far enough north could bring a threat of storms with the area possibly in the warm sector.

There appears more widespread agreement amongst the guidance that as the system passes, a much colder airmass settles in with thicknesses around 1300m, supporting widespread frost/freeze next weekend. The only limiting factor may be wind gusts, which could be elevated with a moderate pressure gradient in place.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

As of 1215 AM Sunday...

There is high confidence in VFR conditions through the 24-hour TAF period. Light winds to start Sunday will transition to be out of the west southwest at 5-8 kt. Mid and high clouds will gradually exit the region this morning and afternoon.

Outlook: VFR conditions are expected through much of the TAF outlook period. A late-week storm system could bring sub-VFR restrictions in rain/showers Thursday into Friday, along with brisk NW winds Friday.

RAH WATCHES/WARNINGS/ADVISORIES

None.