textproduct: Raleigh

WHAT HAS CHANGED

As of 825 PM Saturday...

* Higher confidence in scattered showers and isolated storms over our western and southern Piedmont this evening into the early overnight hours, with a period of gusty winds ahead of and with the showers.

KEY MESSAGES

As of 350 PM Saturday...

1) There remains a marginal risk of hail and strong gusty winds this evening over our southwest counties. There is a non-zero threat of storms Monday in our southeast but confidence remains low.

2) The combination of unseasonably warm temperatures, low humidity, dry fuels, and breezy conditions behind a cold front favor an elevated fire danger risk on Monday.

DISCUSSION

As of 350 PM Saturday...

KEY MESSAGE 1... There remains a marginal risk of hail and strong gusty winds this evening over our southwest counties. There is a non- zero threat of storms Monday in our southeast but confidence remains low.

Satellite imagery this afternoon depicted a diminishing orographic- enhanced cirrus shield over the central Piedmont and Sandhills region. Further upstream, a cu field has started to develop over the higher terrain. Sfc analysis depicted some higher sfc dew points (lower 50s) creeping into the southern Piedmont. While pockets of CIN still exist in this vicinity given the cirrus shield just moved north the past few hours, SBCAPE will develop over the next few hours reaching upwards of 500 J/kg. A weak sfc boundary, largely depicted by a light wind shift and theta-e gradient is still expected to form somewhere along the NC/SC border. Sfc convergence along this boundary, along with the passage of a very weak mid-level perturbation should initiate isolated to scattered convection 1) over the western slopes of the higher terrain, and 2) along and south of the aforementioned weak sfc boundary. Guidance still depicts elongated and straight hodographs (with upwards of 35 knots of effective shear), inverted V profiles, and strong mid-level lapse rates accompanying this CI. As such, there remains the chance for isolated supercells capable of large hail and damaging wind gusts (DCAPE in this vicinity will peak around 900 J/kg). Some CAMs suggest an isolated stronger storms could inch closer to the Triad (weakening with eastward extend but possibly reaching the Triangle). However, given trends associated with the cirrus shield, think it'll be more difficult to destabilize in that vicinity. Any lingering convection will dissipate with time overnight.

After potentially record breaking heat on Sunday (highs in the upper 80s but dry weather expected), a non-zero threat for storms is possible ahead of strong sfc cold front Monday afternoon. Most guidance keeps the deeper moisture transport well to our south and offshore, however there may be a small window where some instability and accompanying stronger shear could produce and isolated stronger storm in the southeast Monday afternoon.

KEY MESSAGE 2... The combination of unseasonably warm temperatures, low humidity, dry fuels, and breezy conditions behind a cold front favor an elevated fire danger risk on Monday.

A moisture-starved cold front will move through central NC in the late morning and early afternoon on Monday, with only a slight chance of showers and storms in the east and southeast. High temperatures will reach the mid-70s to lower-80s, and with dew points crashing into the 30s and 40s behind the front, RH values will drop to 25-30% across the western Piedmont by mid afternoon. Post-frontal gustiness could also reach up to 20-25 mph according to GFS and NAM forecast soundings. While winds look too low for Red Flag Warning criteria, these factors combined with dry fuels could still result in an increased fire danger risk in the west on Monday from mid afternoon to early evening. The SACC outlook continues to highlight that area in a high risk for significant fire potential. Some will depend on the frontal orientation, as most guidance seems to suggest post-frontal winds having more of a northerly vs westerly component, which would somewhat limit downsloping potential. While an IFD may eventually be needed, for now continue to highlight in our HWO.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

As of 825 PM Saturday...

While VFR conditions will prevail over much of central NC over much of the next 24 hours, of most immediate concern is the scattered showers and storms moving NW to SE toward our area and expected to sweep into our far western and southern counties over the next several hours. INT is expected to see an hour or so of gusty winds up to 20-25 kts even well out ahead of the activity, along with a period of mostly light showers and perhaps some thunder between now (00z) and 03z, with brief MVFR vsbys possible. This activity should skirt to the SW of GSO, but there could still be a period of thunder reported. This activity is then expected to move near FAY and perhaps RWI around 02z-07z, and while a few 15-20 kts gusts can't be ruled out at these sites, it is expected to have weakened to just a period of VFR-vsby showers by that time. Otherwise, cigs will be mostly mid-level, above 6kft AGL through daybreak Sun, with winds mostly light (outside of any showers or storms). Skies are expected to trend fair with just high clouds after 11z NW to SE, with minimal clouds Sun. Surface winds after daybreak Sun will be mostly from the SW or WSW at 7-12 kts with periodic gusts to 15-20 kts.

Outlook beyond 00z Mon: VFR conditions are largely expected, although a period of showers with isolated storms are possible Mon afternoon and evening, associated with a strong cold front. The greatest chances for precip will be at FAY. Gusty winds up to 30 kts will be possible at all sites from the SW Mon and from the N and NE late Mon through Mon night.

CLIMATE

Record High Temperatures:

March 22: KGSO: 85/1948 KRDU: 89/1907 KFAY: 88/1948

March 23: KFAY: 86/1948

March 27: KFAY: 87/1946

Record High Minimum Temperatures:

March 21: KGSO: 61/1921

March 22: KGSO: 63/1948 KFAY: 63/1948

March 23: KFAY: 64/1952

March 27: KGSO: 60/2007

RAH WATCHES/WARNINGS/ADVISORIES

None.