textproduct: Raleigh

WHAT HAS CHANGED

* Continued increasing confidence in widespread rain, locally heavy at times, through the middle of next week. Rainfall amounts during this time are expected to range from 2 to 4 inches on average.

KEY MESSAGES

As of 140 PM Friday...

1) Cool and rainy this afternoon and tonight over much of the Piedmont and northern Coastal Plain with a CAD wedge in place. South and east of the wedge will be warmer with scattered showers and storms.

2) Saturday will feature a wide range of temperatures, ranging from well below normal in the Triad to near normal across the Southeast.

3) A front that will linger across the region will bring high precipitation chances throughout the next seven days.

DISCUSSION

As of 140 PM Friday...

KEY MESSAGE 1... Cool and rainy over much of the Piedmont and northern Coastal Plain with a CAD wedge in place. South and east of the wedge will be warmer with scattered showers and storms.

This Afternoon through Evening: A sharp temperature gradient will persist across the region this afternoon as a Cool Air Damming wedge boundary sets up across the Piedmont. North of this boundary, across the northern Piedmont and northern Coastal Plain, cool conditions will remain locked in with temperatures stuck in the upper 50s to low 60s. To the south and east, warmer temperatures will reach the low-to-mid 70s, where around 1000 J/kg of SBCAPE is triggering isolated showers and thunderstorms. While this convective activity is currently limited to the far southeast Coastal Plain, coverage is expected to expand northward overnight as a weak frontal boundary lifts across the area.

Tonight through Early Saturday Morning: The best chance for widespread precipitation will arrive during the overnight hours and persist into early Saturday morning. While hi-res model guidance shows some disagreementwith some solutions favoring lighter rain overnight and others depicting a more robust scenario with heavier showers and stormsthe overall trend will be a steady increase in rain chances overnight.

KEY MESSAGE 2... Saturday will feature a wide range of temperatures, ranging from well below normal in the Triad to near normal across the Southeast.

With high pressure off the New England coast, northeast flow has allowed for cold-air damming to develop across North Carolina. While the wedge front is expected to eventually retreat to the north and bring central North Carolina back into the warm sector, the timing that the wedge front retreats is something that is tricky for computer models - and there is high bust potential for tomorrow's temperatures. Considering the models usually show CAD retreating too quickly, will go with a slower model solution that keeps cooler air pinned into the Triad through the day, while allowing temperatures to warm up a bit across southern counties. The forecast calls for temperatures to rise near 70 degrees in the Triad, while the Triangle should climb into the mid 70s and Fayetteville into the low 80s. After the front retreats to the north Saturday night, highs through the rest of the forecast will generally be in the low 80s across the north and mid 80s across the south.

KEY MESSAGE 3... A front that will linger across the region will bring high precipitation chances throughout the next seven days.

A second shortwave moving northeast across the Appalachians on Saturday should help trigger the next round of precipitation, once again favoring western locations. A stronger line of thunderstorms could approach western counties late Saturday afternoon, although the Day 2 SPC Convective Outlook does not show a severe threat across these counties. By the time the wedge front moves north of the region, likely by Sunday morning, there should be a wide swath of showers extending from New England all the way southwest into Texas. While there will no longer be a wedge across the Carolinas, the front should remain nearly stationary into the middle of next week, generally draped from the mid-Atlantic west into the central Plains and extending south into Texas. High pressure over the western Atlantic will result in southerly flow across the southeastern United States, continuing to pump warm, moist air into the region. There are some indications that the front could drop south of the area Wednesday into Thursday, which would put central North Carolina onto the drier side of the front and bring a reduction in the chance of rain for the end of the week. However, over the next seven days, the forecast calls for a broad area of two to four inches of rain across the entire forecast area.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

As of 130 PM Friday...

Widespread IFR conditions will continue across the region through the period as CAD wedge remains in place. Periodic light rain and mist will keep visibilities in the MVFR/IFR range, with the lowest ceilings (~400 ft) expected late tonight into Saturday morning. KFAY and KRDU may see a brief, slight improvement to low-end MVFR late this afternoon, though have a PROB30 for TSRA at KFAY this afternoon into early evening as storms begin to expand north. Winds will generally remain out of the northeast around 5-10 kt, with some minor easterly veering at the eastern sites tomorrow morning. Expect very little relief through Saturday afternoon, with ceilings holding at IFR levels.

Outlook: The persistent CAD wedge is forecast to stick around through much of Sunday before eroding. Widespread IFR/LIFR stratus and patchy fog will remain a strong possibility overnight Saturday into Sunday morning. However, convective and ceiling patterns will transition into a standard diurnal trend Sunday through mid-week, featuring periods of VFR/MVFR daytime conditions outside of scattered afternoon and evening showers and thunderstorms.

CLIMATE

Record High Minimum Temperatures:

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.