textproduct: Raleigh

WHAT HAS CHANGED

* Updated aviation discussion to reflect the 00z TAFs.

KEY MESSAGES

As of 1250 PM Sunday...

1. Strong to severe storms will be possible today. Water loaded downbursts will bring a primary hazard of damaging straight-line winds.

2. There will be minimal showers and storms Monday through Wednesday before widespread precipitation arrives on Friday.

3. Heat returns for Thursday and possibly Friday

DISCUSSION

As of 1250 PM Sunday...

KEY MESSAGE 1... As of 16Z, many of the CAMs (and esp the HRRR) have underrepresented the existing convection that is currently moving across the NC mountains and that raises concerns regarding downstream convective evolution across central NC later today.

Overall, the severe weather threat remains dependent on the degree of convective organization that can be maintained as mountain convection moves east and interacts with a moderately unstable and very moist air mass across the Piedmont and Coastal Plain. MLCAPE values of 1500-2500 J/kg (higher CAPE values east), steep low-level lapse rates, and DCAPE supportive of strong downdrafts should favor damaging straight-line winds as the primary hazard. In addition, the CAMs which are more robust with convection evolution and coverage today also appear to be taking advantage of pre-existing mesoscale dewpoint boundaries and perhaps the Piedmont trough convergence and thus depict widely scattered single-cell storms developing ahead of the convection that is currently to our west. Given the aforementioned CAM uncertainties, greater forecast weight will be placed on observational trends and the evolving mesoscale environment. Its worth noting again that any of the stronger/taller cells later today will be capable of producing localized damaging wind gusts.

KEY MESSAGE 2... A front should generally be along the I-95 corridor Monday morning and will continue to drift to the Atlantic coastline by Tuesday morning before moving offshore on Wednesday. With central North Carolina on the cooler and drier side of the front, the chances for precipitation the next few days should be greatly reduced. Any diurnally driven storms Monday through Wednesday should be east of I-95 and relatively isolated in coverage. The next widespread chance for precipitation will come with low pressure that will pass over the Great Lakes on Thursday and continue northeast along the Canadian/United States border Friday and Saturday. The associated cold front could bring a late day storm to the Triad on Thursday, but will bring most of its precipitation to central North Carolina Friday and Friday night.

KEY MESSAGE 3... High temperatures will be noticeably cooler on Monday, with values 5 to 10 degrees cooler than Sunday. Tuesday will vie for the coolest day of the week with all locations remaining in the 80s. Temperatures will then begin to rise again by Wednesday with a return to the 90s, and some locations pushing triple digits by Thursday. The timing of the next cold front will determine how warm temperatures rise on Friday, but Saturday should drop back into the 80s again. With lower humidity values through mid week, heat indices will be similar to air temperatures Monday through Wednesday. Increasing humidity along with increasing temperatures may require a heat advisory on Thursday.

AVIATION /00Z MONDAY THROUGH FRIDAY/

As of 815 PM Sunday...

Through 00Z Tuesday: Clusters of showers and storms are currently moving east into the Coastal Plain. They have largely cleared all TAF sites except RWI which could see a heavy downpour, lightning, gusty winds, and brief sub-VFR conditions over the next hour or so if a storm passes overhead. This should be the end of the best rain chances, but scattered showers and perhaps an isolated storm can't be ruled out this evening into the early overnight hours if convection currently over the Mountains is able to make it into our western zones. Otherwise, VFR conditions will prevail through the period with just some broken mid and high clouds that become more scattered on Monday. A cold front will move through from NW to SE overnight into early Monday morning (from about 07z to 13z). This will bring a wind shift from SW to NW, remaining around 7-10 kts with gusts to 15-20 kts possible at times. Can't rule out patchy fog later tonight where rain fell today, if it can occur before the cold frontal passage brings in much drier air. However, confidence in it occurring is too low to include mention in the TAFs at this time.

Outlook: Mostly dry conditions are expected from Monday through Wednesday, with only a slight chance of a stray shower or storm in the afternoon and evening in the far south and east (including FAY and RWI). There is a better chance of convection in the northwest (including INT and GSO) on Thursday, but the most widespread shower/storm coverage across all of central NC will be on Friday and Friday night as the next cold front moves through. While not likely, sub-VFR ceilings and mist can't be ruled out overnight into early morning where heavier rainfall occurs during the afternoon/evening convection, with a better chance by Friday.

CLIMATE

Record High Temperatures:

June 14: KGSO: 98/1926 KRDU: 97/1944 KFAY: 100/2022

June 18: KGSO: 100/1944 KRDU: 98/2015 KFAY: 102/1944

Record High Minimum Temperatures:

June 14: KGSO: 71/2025 KRDU: 79/2022 KFAY: 77/2022

June 15: KGSO: 74/2022 KRDU: 78/2025 KFAY: 76/1926

June 18: KGSO: 73/2018 KRDU: 77/2025 KFAY: 76/2017

June 19: KGSO: 77/1970 KRDU: 73/2025 KFAY: 77/2017

RAH WATCHES/WARNINGS/ADVISORIES

None.