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 /18Z SUNDAY THROUGH FRIDAY/

As of 155 PM Sunday...

In a cool and moist post frontal environment, MVFR CIGS are widespread across central NC with some lingering IFR conditions in the Sandhills and southern Coastal Plain this afternoon. Some patchy drizzle and even a little light rain was still noted as of 17Z across the southern and central Coastal Plain and Sandhills resulting in some minor VSBY reductions. A north to northeast wind at 8 to 14 kts with gusts of 16 to 22 kts continues across the area.

Outside of the southern and central Coastal Plain and Sandhills, CIGS have slowly lifted this afternoon with bright spots developing and some breaks in the overcast now observed in visible satellite across the western Piedmont, near the KINT and KGSO terminals. This trend should continue this afternoon with most of the western and northern locations transitioning to marginal MVFR and VFR conditions before sunset. The drizzle/light rain and stubborn low clouds across southeastern locations including the KFAY terminal will linger for another hour or two resulting in a brief window for improvement late this afternoon.

After sunset, there is a good chance that MVFR CIGS redevelop and expand northwest overnight from KFAY and KRWI late this evening toward midnight and KRDU and possibly KGSO late tonight. The low stratus will feature bases around 2-3kft feet and it is still little unclear if skies will be more BKN or SCT but in general, aviation conditions will marginally deteriorate this evening and especially overnight. While wind gusts will diminish this evening, a rather steady wind of 8-12 kts from the NNE will continue overnight, precluding any fog or VSBY restrictions. The low stratus will break up much faster on Monday morning allowing VFR conditions to return by mid morning or so.

Looking beyond 18Z Monday, VFR conditions are generally expected for Monday afternoon through at least early Tuesday. A couple of disturbances will move across the area on Tuesday and Tuesday night, bringing a small risk of a shower across northern and western areas. A better chance of showers and possibly storms arrives for Wednesday and Wednesday night as front moves across the area. A return to more fair weather albeit with some gusty winds is expected for Thursday and Friday. -Blaes

RAH WATCHES/WARNINGS/ADVISORIES

None.