textproduct: Raleigh

WHAT HAS CHANGED

No major changes since prior forecast package.

KEY MESSAGES

1) Multiple waves of light precipitation possible Wednesday. A brief change over to snow flurries/light snow possible before sunrise Thursday but little to no impacts expected.

2) Below to well below normal temperatures and potential fire weather concerns Thu and Fri.

3) Primarily dry weather through the extended forecast period, with just a slight chance for a brief, trace amount of rain and/or snow along the VA border over the weekend.

4) Below to well below normal temperatures return Sat night-Tue.

DISCUSSION

KEY MESSAGE 1: Multiple waves of light precipitation possible Wednesday. A brief change over to snow flurries/light snow possible before sunrise Thursday but little to no impacts expected.

A rather dynamic northern stream trough will dig into the Deep South Wednesday. Simultaneously, a southern stream jet streak will eject east across FL/GA. This southern stream system will lkely generate light rain across the coastal areas and inland across the Coastal Plain Wednesday afternoon. Generally expecting trace to maybe a few hundreds of an inch of rain during this time.

The northern stream upper trough's base will phase with the southern stream jet later Wednesday. Upper forcing associated with these features, and ahead of an advancing cold front will possibly generate light precipitation overnight through sunrise Thursday. Initially starting as very light rain, temperatures through the depth of the atmosphere may cool enough to briefly mix or change over to snow in some locations between ~06 and 12Z Thursday. Overall, the latest guidance would concur with prior forecasts that if the cold air can catch the departing moisture (which in general is not overly anomalous over our area), then at best some locations may see a brief period of flurries or very light snow showers. Would not expect any accumulations as 1) saturation/omega in the DGZ is not overly impressive and as such any evaporative cooling/wet bulbing may be limited overall and 2) forecast soundings indicate dry air advection in the lower-levels ramping up just before sunrise in that optimal temporal period. It's worth noting, however, that the HRRR is an outlier here and does maintain deeper saturation depth during this period which if realized could support a dusting and/or light accumulations. For now though, will go with model consensus and keep accumulations to zero.

Highs on Wednesday will reach the mid 50s. Overnight lows in the mid to upper 20s.

KEY MESSAGE 2: Below to well below normal temperatures and potential fire weather concerns Thu and Fri.

Aloft, the s/w trough will swing ewd across the region Thu and lift away from the area Thu night. In the wake of the cold front, a cP airmass will advect into the area on Thu, while the pressure gradient remains strong across central NC as the surface high tracks ewd across the Gulf Coast. Low-level thicknesses should be in the 1260-1270 meter range. In addition to the surface pressure gradient, deep mixing is also expected. As a result, Thu should be breezy, with some 25-30 kt winds possibly mixing down to the surface. The sfc high will shift offshore by Fri, with winds becoming sly-swly, but still breezy/gusty with a continued tight sfc pressure gradient as a deep low tracks across the nrn Great Lakes and strengthening LLJ over the area. Potential fire weather concerns, with RH in the 20-30 percent range and gusts of 20-30 kts possible.

KEY MESSAGE 3: Primarily dry weather through the extended forecast period, with just a slight chance for a brief, trace amount of rain and/or snow along the VA border over the weekend.

While the forecast should largely be dry Sat and Sun, there is a slight chance for a brief period of rain and/or snow, mainly along the VA border with the passage of a s/w trough aloft. However, timing of the s/w remains uncertain, as is the available moisture and potential for precipitation to reach the ground or accumulate. Regardless, expect trace-light amounts at best, with little to no overall impacts. Otherwise, a dry forecast should prevail through early next week.

KEY MESSAGE 4: Below to well below normal temperatures return Sat night-Tue.

The below to well below normal temperatures should return Sat night/Sun and continue through early next week. However, there is still some model variability wrt timing the arrival/departure of the cold air (there will be two separate Arctic highs that could impact the area between Sat and Tue night), resulting in a wide spread in the temperature guidance for that period.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

As of 100 PM Tuesday...

VFR conditions will prevail as dry high pressure settles south of the area. A weakening southern stream disturbance moving east ahead of an amplifying northern stream trough and attendant cold front will cause cloud cover to increase and thicken; however conditions will remain VFR through the period. Very light rain and/or sprinkles may reach KFAY by midday or early afternoon Wednesday, but precipitation intensity appears too light and fleeting to cause any aviation impacts or restrictions.

Light SW surface winds will increase this afternoon, occasionally gusting to 15 to 18 kt. Gustiness will subside this evening.

Marginal low-level wind shear will be possible tonight into early Wednesday morning as a 30-35 kt SWLY LLJ spreads east across the region. The threat will diminish after daybreak Wednesday, as surface SW gusts of 15 to 25 kts develop during mid to late morning.

Outlook: A band of mostly light rain showers, potentially accompanied by a brief period of MVFR restrictions, will spread west to east across the area Wed night-Thu morning. Precipitation could briefly transition to a rain-snow mix early Thursday morning before ending. Strong and gusty nwly winds are expected Thursday, with frequent NW gusts between 20 to 25 kts.

Predominately dry VFR conditions are expected through the weekend.

RAH WATCHES/WARNINGS/ADVISORIES

None.