textproduct: Raleigh

WHAT HAS CHANGED

* No major changes made.

KEY MESSAGES

As of 215 PM Sunday...

1) Marginal fire weather concerns persist for Monday and Tuesday.

2) A cold front will bring showers and storms, some possibly strong, to the region Wednesday night into Thursday.

DISCUSSION

As of 215 PM Sunday...

KEY MESSAGE 1...Marginal fire weather concerns persist for Monday and Tuesday.

As the surface high pushes offshore and places us within a gradually strengthening SW flow, our daytime surface winds will increase. Sustained speeds/gusts are expected to peak at 10-15 mph/15-20 mph Monday, with min RH of 25-35% in the Piedmont and 35-40% in the east. By Tuesday, sustained speeds/gusts are expected to top out at 12-18 mph/20-30 mph with min RH values of around 30-40%. None of these values quite reaches levels strongly suggesting an increased fire danger, but with ongoing drought conditions and still-dry fuels over much of the area, there may be a low-end threat for adverse fire behavior both days. This threat will be highest in the NW CWA, which saw very little or no rainfall Sat. Will monitor conditions and confer with forestry officials this week.

KEY MESSAGE 2...A cold front will bring showers and storms, some possibly strong, to the region Wednesday night into Thursday.

Medium-range guidance continues to come into better agreement with the overall evolution of the system mid-week. There is some interaction between the nrn stream trough and embedded s/w with the srn stream low/trough over the Baja. However, the srn stream low gets cutoff from the longwave trough as the nrn stream s/w and trough continue ewd across the cntl and ern CONUS Wed night through Thu night. At the surface, as a cold front approaches from the northwest Tue night/Wed, a warm front will lift nwd across the area, with increased advection of warm, moist air in its wake. The eastward progression of the cold front will slow a bit as it moves into the Appalachians Wed night/early Thu, while an area of low pressure lifts newd along it. There continue to be differences in the available guidance wrt the strength, track, timing of the low and subsequent fropa on Thu. The most likely fropa timing is still Thu eve or early Thu night, with the front through central NC by or shortly after midnight Fri. Cool high pressure will ridge into the area as it moves across the Deep South/Southeast US in the wake of the cold front.

While a few showers are possible across the northwest Piedmont on Wed in the wake of the warm front and with the passage of a mid- level disturbance, coverage and chances remain somewhat limited. The chances and coverage will increase from the NW Wed night into Thu as the s/w aloft swings across the region and the surface cold front approaches from the west. On Wed, the NAM forecast soundings show deep layer shear of 40-50 kts, with CAPE of 500-1000 J/Kg across much of the area. However, the GFS forecast soundings are much more stable, with less than 500 J/Kg. For Thu, expect a high shear, low CAPE environment across the area, with deep layer shear of 60+ kts but CAPE of 500 J/Kg or less and max PWATS of 1.5-1.7" (based on the GFS forecast soundings). Abundant cloud cover and pre-frontal convection arriving early could both limit the available instability with the fropa Thu aft/eve. Will need to keep an eye on how the forecast evolves for both Wed and Thu to determine potential for strong to severe storms, but for now a fair amount of uncertainty remains.

AVIATION /00Z MONDAY THROUGH FRIDAY/

As of 731 PM Sunday...

TAF period: VFR conditions are expected through 00z/Tuesday.

Outlook: VFR conditions are forecast through at least Tuesday night, when the first chance of rain arrives at INT/GSO. The chance for rain and restrictions will increase through the day Wednesday at all terminals, with rain and restrictions likely Wednesday night and Thursday. Rain will come to an end Thursday night, along with a return to VFR conditions by Friday.

RAH WATCHES/WARNINGS/ADVISORIES

None.