textproduct: Raleigh

WHAT HAS CHANGED

* Updated key message for Saturday.

KEY MESSAGES

As of 1210 PM Friday...

1) A disjointed disturbance brings some isolated rain Saturday and a few late-day showers Saturday evening.

2) Next chance of showers, albeit low impact, will come Sunday into Monday. And, again mid-week.

DISCUSSION

As of 1210 PM Friday...

KEY MESSAGE 1... A disjointed disturbance brings some isolated rain Saturday and a few late-day showers Saturday evening.

High pressure situated over the area today will shift offshore tonight and Saturday, allowing for return flow and warmer weather for the start of the weekend. High should largely be in the upper 70s, with even a few locations topping out around 80.

Aloft, a few disjointed mid-level shortwaves will track across the area. A northern disturbance will skirt mainly north of NC across the lower OH and Mid-Atlantic region, while a southern stream wave tracks along the Deep South into portions of GA/SC. These systems will track through during the morning and early afternoon. Most of this energy will bypass central NC, leaving most areas staying dry. The one exception will be across our southern areas of the Sandhills, Coastal Plain and southern sections of the Triangle. Isentropic lift and WAA in the 850-700 mb layer will support some isolated to scattered light rain or sprinkles during the morning and some early afternoon showers or isolated thunder. Rain amounts will be a tenth of an inch or less, though the 12z HRRR suggests a high- end potential up to a quarter inch over the Sandhills.

Later in the day, a surface lee trough will set up along the Appalachians. Surface instability upwards of 500 J/kg combined with 40+ kt of deep-layer shear may support some late day and early evening showers or isolated storms over the northwest Piedmont. Activity would be limited to the daytime, diminishing near sunset with loss of heating. The latest HRRR and NAM-NEST support this scenario, though activity should be relatively narrow as it tracks east.

We cannot rule out some patchy fog or low stratus early Sun, especially over areas that saw WAA stratiform rain earlier in the day across the south.

KEY MESSAGE 2... Next chance of showers, albeit low impact, will come Sunday into Monday. And, again mid-week.

The next chance of showers appears to be on Sunday morning and then again late Sunday into Monday. It still looks as though the higher instabilities and deeper moisture will be just to our south and east Sunday morning with an exiting disturbance that will bring a chance of showers in the SE part of NC early Sunday. Later Sunday into Monday, a weak surface trough will be located over the Piedmont Sunday night into Monday morning as a rather weak mid/upper short wave approaches from the west. There is a chance that some higher low level moisture may creep into the region ahead of the cold front; however, as of right now most models generally depict another light QPF event with only a chance of showers Sunday into Sunday night. There may be a higher chance of showers - into the likely category - mainly in the central and eastern areas Monday morning as the main cold front moves east through the region. Again, the Sunday into Monday shower chances and QPF appear to be low impact with low QPF (less than 0.25) and generally scattered showers.

Looking ahead to the rest of the week, the next chance of needed showers should be Wednesday into Wednesday night with yet another cold front. Temperatures will remain rather mild to even cool at times after the cold frontal passages. Highs in the upper 70s to lower 80s Sunday, and mostly upper 60s to mid 70s Tuesday and Wednesday.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

As of 645 AM Friday...

Areas of IFR and LIFR restrictions have developed across much of the Piedmont, Sandhills and Coastal Plain early this morning as areas of fog and low stratus have developed and shifted southeast across the area. The fog that developed across parts of the Triad has largely dissipated as drier air has moved into the area from the northwest.

Conditions will improve shortly after daybreak as the sun and mixing clears out the fog and stratus and the boundary layer dries out resulting in mostly clear skies. Expect VFR conditions and light and variable surface winds from mid morning through the rest of today and into tonight. Some low stratus may develop very late tonight as a return flow pattern develops with some CIG restrictions possible across southern locations.

Outlook: A couple of disturbances and frontal systems will bring a risk of adverse aviation conditions to the area with a risk of rain Saturday and Saturday night with another round on Sunday and especially Monday. -Blaes

RAH WATCHES/WARNINGS/ADVISORIES

None.