textproduct: Raleigh

WHAT HAS CHANGED

* Made a downward adjustment to high temperatures on Friday and Saturday.

KEY MESSAGES

As of 243 PM Wednesday...

1) Continued hot this afternoon. Patchy fog possible overnight.

2) Rain chances return Thursday, with chances persisting into early next week. Low confidence in high temps Friday and Saturday with a CAD wedge in place.

DISCUSSION

As of 243 PM Wednesday...

KEY MESSAGE 1... Continued hot this afternoon. Patchy fog possible overnight.

Satellite and sfc analysis this afternoon depicted an upstream cold front moving across the Ohio Valley and into the Mid-Atlantic. Further offshore, a sfc low was evident just off the Carolina coastline. Here locally, light wswly sfc flow continues this afternoon as temps have largely pushed into the upper 80s/lower 90s. Expect a few more degrees to squeeze out the next few hours. Winds should subside some this evening, but a little stirring may persist overnight. Where winds go calm, patchy fog may be possible. Best chances would be down in the southeast.

KEY MESSAGE 2... Rain chances return Thursday, with chances persisting into early next week. Low confidence in high temps Friday and Saturday with a CAD wedge in place.

Aloft, after the passage of a weak s/w disturbance Wed night/Thu and with a low lingering near the Caribbean, the sub-tropical ridge may once again strengthen and lift newd across the region Thu night through Fri night, with several s/w disturbances tracking across the Plains and MS Valley. One of the shortwaves will lift newd across the region Sat/Sat night, with high pressure strengthening again off the Southeast US coast through early next week, a s/w or two clipping the area in the meantime. At the surface, cold front approaching from the north will slide southward across central NC Thu aft/eve. A CAD air mass should set up Thu night and remain in place through at least Fri night/early Sat as high pressure tracking across the Northeast US and offshore ridges swd into the area,with warm, moist air overrunning the cool, stable boundary layer resulting in overcast skies and rain. Still expect the wedge to erode sometime Sat or Sat night, with the front lifting nnwwd back across the area. However, the GFS keeps the wedge locked in over the far northwest Piedmont into Sun. The spread in available guidance increases beyond Sat, with significant differences and forecast implications for central NC.

Precipitation: The best chances for showers/storms will be Thu along and ahead of the backdoor cold front as it moves into and across the area. In the wake of the front, warm air advecting in above the cooler, stable boundary layer should result in some rain through at least Sat over central NC. Regardless of what happens with the wedge, expect daily chances for precipitation (character may vary across the area) Sat-Mon, with temperatures and instability the primary factors driving the precip uncertainty. Where/when the wedge erodes and a warm front lifts nwd across the area, there will be the chance for additional diurnally driven convection on the warm side of the boundary, while rain will be favored north of it. Do not expect a washout for Sun-Tue and the precipitation probabilities may be overdone given the uncertainty and model spread, but there will be the chance for showers/storms at some time/location each day.

Temperatures: Highs Thu will be impacted by the timing of the front and the convection ahead/along it. For now, expect the rain to arrive in the late aft/eve, so highs should range from mid/upper 80s north to low/mid 90s south. The caveat is that if the cloud cover, showers, and front arrive earlier those highs could be a bit overdone, especially across the north. There is a large bust potential wrt highs on Fri and Sat given the potential for CAD to set up linger, especially if there is continued rain into it. For now have highs ranging from mid/upper 60s north to low/mid 80s south, but with below average confidence. It is possible highs could be off by 5-10 degrees in some spots. The operational 12Z runs of the NAM and GFS both have highs in the mid/upper 50s over the NW Piedmont and low/mid 60s over the Triangle on Fri. On Sat, with the wedge lingering, highs currently forecast to range from low 70s NW to mid 80s south. Lows Thu and Fri nights expected to range from mid 50s north to mid 60s south. Generally expect temperatures to moderate back to near or slightly above normal by early next week, but timing of that will depend on when the wedge erodes.

AVIATION /17Z WEDNESDAY THROUGH MONDAY/

As of 1248 PM Wednesday...

VFR conditions persist this afternoon under generally sunny skies. A few light gusts of up to 15 kts or so have been observed across northern locations. Some stirring is possible overnight, but winds should be generally light. Some guidance hints at marginal LLWS, but think the threat should be quite limited, if at all.

There's a bit of a mixed bag as far as possible overnight fog and or stratus early Thursday morning. Went ahead and added a few TEMPO groups at KRDU/KFAY/KRWI to account for possible lower ceilings and mist/reduced visbys. Confidence isn't high though.

Convection is expected to blossom across central NC Thursday afternoon via a short-wave aloft and an advancing backdoor cold front. However, high-res guidance generally holds off on precipitation at all terminals till near or just after 18Z. Will hold off on introducing any restrictions till the next TAF package.

Outlook: Showers and storms will persist Thursday afternoon and evening along with gusty nely sfc winds. Sub-VFR ceilings also look to persist into Friday in the Triad and potentially RDU as a CAD regime looks to set up over the region. Daily shower/storm chances will also be possible through early next week.

CLIMATE

Record High Temperatures:

May 20: KGSO: 95/1917 KRDU: 96/2022 KFAY: 99/2022

May 21: KRDU: 96/1941 KFAY: 99/1941

Record High Minimum Temperatures:

May 20: KGSO: 68/2022 KRDU: 69/2019 KFAY: 71/2022

May 21: KGSO: 67/2022 KRDU: 71/1898 KFAY: 71/2025

May 22: KFAY: 73/2004

May 23: KFAY: 72/2011

May 24: KRDU: 70/2011 KFAY: 72/2000

May 25: KGSO: 70/2019 KRDU: 71/2019 KFAY: 71/2019

May 26: KGSO: 70/2019 KRDU: 73/2011 KFAY: 75/2004

RAH WATCHES/WARNINGS/ADVISORIES

None.