textproduct: Raleigh

WHAT HAS CHANGED

* Downward trend in high temperatures today continues.

KEY MESSAGES

As of 200 PM Sunday...

1) Much cooler tonight, rain should move out this afternoon.

2) An active weather pattern continues with a few systems that could bring more beneficial rainfall to central NC into early May.

DISCUSSION

As of 200 PM Sunday...

KEY MESSAGE 1... Much cooler tonight, rain should move out this afternoon.

Aloft, a s/w will swing across the area through this evening and offshore tonight. At the surface, the effective cold front was well south of the area as of 16Z, while a reinforcing front was sliding swd across the srn Piedmont, Sandhills, and srn Coastal Plain. In the wake of the front, the ridge will build into and strengthen over the area through tonight before slowly shifting ewd and weakening Mon/Mon night. Some light rain lingers in the behind the reinforcing front, with some embedded showers along it. It is looking less likely any thunder will occur in central NC with the showers given the earlier timing and lower instability. Forecast high temperatures also continue to decrease, with highs now expected to range from around 60 degrees NE to low 70s SW. That may be overdone where rain lingers longer than anticipated. Nnely winds of 10-15 mph with gusts to around 20 mph will linger through the aft and into the early evening, then gradually decrease through tonight, but remain stirred/breezy as the ridge strengthens and cold air advects into the area. Lows generally in the 40s expected. Near to slightly below normal temperatures expected Mon and Tue.

KEY MESSAGE 2... An active weather pattern continues with a few systems that could bring more beneficial rainfall to central NC into early May.

The forecast for Wed will be our next chance for widespread light rain. A convectively modified low-amplitude shortwave over the central/southern Plains Tues evening negatively tilts as it moves through the TN Valley and into the Mid-Atlantic Wed morning. This wave along with forcing along the nose of strengthening upper-lvl jet streak will supply deep lift within a plume of richer PWAT of 1 to 1.5 inches. Reasonable low-end amounts show at least measurable across all of central NC with higher amounts around 0.5". In the wake of the mid/upper-lvl moisture band, continued moist and warming boundary layer may support additional showers/storms during the afternoon/evening hours; although this scenario is highly conditional.

A cold front trailing the aforementioned system will become relatively stationary over the Southeast into the weekend. Troughing is generally favored over the eastern US, though with a high degree of complexity owing to blocking over the northern Atlantic and upper lows over Canada. A shortwave trough is forecast to track across the southern US late in the week, bring a good chance of rain to the drought-stricken region, but the track is uncertain, and there are scenarios where it remains suppressed and NC is mostly dry. Thus confidence is low at this time. The ECMWF AIFS ensemble is likely the best case scenario at the moment among ensemble solutions for appreciable rainfall for central NC, which features a low track generally across GA/SC and off the Carolina coast with 50-60% probabilities of > 0.5", maximized along with NC/SC border.

AVIATION /00Z MONDAY THROUGH FRIDAY/

As of 640 PM Sunday...

Areas of MVFR stratus will be the main story for the next 24-hour TAF period. While pockets of VFR have developed, especially across the Triad terminals, satellite imagery reveals additional MVFR stratus moving southwest out of VA in the cool and moist NE flow. Forecast soundings from several models/ensembles show these MVFR ceilings redeveloping across the Triad tonight and persisting at RDU/FAY/RWI into Mon morning to early afternoon. The MVFR will be quickest to erode at GSO/INT around 11/12z and latest at FAY/RWI between 16-17z. It is possible that these ceilings will lift to VFR earlier than presently anticipated, but given the moisture trapped below the inversion, confidence was not high enough to improve conditions sooner. NE winds with occasional gusts to 18 kt will remain in place through Mon evening.

Outlook: VFR conditions return Monday afternoon. A disturbance will move across the area on Tuesday, bringing a small risk of a shower at GSO/INT. A better chance of restrictions in showers and perhaps storms arrives Wednesday with a stronger area of low pressure. VFR should prevail Thu and Fri.

RAH WATCHES/WARNINGS/ADVISORIES

None.