textproduct: Raleigh

WHAT HAS CHANGED

* No major changes to the local forecast. SPC has added a Slight Risk (level 2 of 5) of severe weather across VA and far northern NC for Monday.

KEY MESSAGES

As of 220 AM Sunday...

1) Isolated severe storms possible Monday afternoon and evening, mainly across the western and northern Piedmont.

2) Another brief hot spell peaks Mon, when highs will be in the mid- upper 90s with heat index values near 100F, mainly along and east of Highway 1.

DISCUSSION

As of 220 AM Sunday...

KEY MESSAGE 1... Isolated severe storms possible Monday afternoon and evening, mainly across the western and northern Piedmont.

A strong shortwave trough will cross the Ohio Valley and Mid- Atlantic on Monday, with a trailing cold front poised to cross central North Carolina Monday evening and overnight. Moist southerly flow ahead of the cold front will send dew points into at least the mid-60s, if not around 70, based on some guidance, resulting in the potential for 1000-2000 MLCAPE, particularly across the western Piedmont where some mid-level capping will be more apt to erode due to approaching height falls. The belt of strongest mid-level flow looks to be maximized north of our area along with the presence of surface pressure falls and low-level backed flow, but 20-25 knots of bulk sfc-500mb shear will help support a severe threat. DCAPE should also be relatively high across the Piedmont, which may further support some upscale merging of cold pools and a straight-line damaging wind threat as storms move off the mountains. Currently, the SPC has all of Central North Carolina in a Marginal Risk, with a Slight Risk just to our north, and AI NWP Convective Hazard Forecasts favor mostly the Piedmont where the timing of the synoptic front and any preceding outflow boundaries interact with peak diurnal heating.

WPC has western NC in a Marginal Risk for flash flooding, but with QPF having decreased a bit overall and and area average amounts of just 0.25-0.50", any minor flooding would be very localized and likely in urban areas around the Triad.

KEY MESSAGE 2... Another brief hot spell peaks Mon, when highs will be in the mid-upper 90s with heat index values near 100F, mainly along and east of Highway 1.

A warm and increasingly humid SW flow returns Mon ahead of the slowly approaching cold front. While this period of hot weather does not appear to be especially profound or long-lasting, much of the eastern half of central NC, including from the Triangle region to the south and east, are likely to see afternoon heat indices peaking around 100F. This is also where the NWS experimental Heat Risk reaches the Major category (level 3 of 4), indicating atypically high heat that could lead to an increased risk of heat illnesses, especially for vulnerable populations. People needing to work or exercise outdoors Mon should take precautions and plan for frequent shade (or AC) and hydration breaks. Temps on Tue will remain above normal with elevated humidity, but the increase in clouds should keep temps and heat indices just under critical values.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

As of 200 AM Sunday...

A residual continental (dry) airmass over cntl NC will favor VFR conditions through at least 06Z Mon. Mainly light swly surface winds may become weakly gusty into the teens kts at times with heating this afternoon.

Outlook: Return flow moisture will yield a chance of probably MVFR stratus at FAY Mon morning and scattered convection, with maximum coverage over the Piedmont, Mon afternoon-evening. A chance of convection will linger into Tue with the passage of a cold front, especially from FAY to RWI, though with probably only isolated coverage owing to increasingly-westerly (downslope) low-level flow.

CLIMATE

Record High Temperatures:

June 22: KRDU: 100/2022 KFAY: 101/2022

Record High Minimum Temperatures:

June 22: KGSO: 75/1981 KRDU: 78/1933

June 23: KGSO: 74/2024 KRDU: 78/2024 KFAY: 77/2024

RAH WATCHES/WARNINGS/ADVISORIES

None.