textproduct: Raleigh

SYNOPSIS

A warm front will move north into the region late tonight into Friday. A cold front will then sweep across central NC Saturday night.

NEAR TERM /TODAY THROUGH TONIGHT/

As of 353 AM Friday...

Weak mid-level impulses and isentropic upglide continue to generate scattered light rain across central NC this morning. Mostly trace to a few hundreds of an inch of rain have been observed thus far. However, a band of steadier rain is quickly approaching the Triad this morning and should likely squeeze out a bit more (a few hundreds to maybe a few tenths) as it moves across the western to central Piedmont and Coastal Plain through late this morning. Expect a relative lull in rain through much of this afternoon and early evening. By later tonight, weak mid-level impulses and increasing WAA should trigger additional light rain primarily along the NC/VA border early before filling in further south through sunrise Saturday morning. A few tenths of an inch of rain are expected Friday night through 12Z Saturday.

Dense fog has developed just outside the southwestern Piedmont down in SC this morning. Latest guidance has backed off advecting this dense fog up into our southern Piedmont (cloud cover is pretty extensive here as well). As such, think the fog chances may be more limited than previously expected but can't fully rule it out. Otherwise expect high temperatures in the lower 60s (NE) to lower 70s (SW). Overnight lows in the upper 50s to around 60 are expected.

SHORT TERM /SATURDAY AND SATURDAY NIGHT/

As of 354 AM Friday...

A potent short-wave and associated mid-level height falls will move over central NC late Saturday afternoon and evening. Forcing from this feature will trigger pre-frontal showers and storms across central NC Saturday afternoon and evening.

Lingering light rain via weak mid-level impulses will likely be ongoing along and east of US-1 early Saturday. This initial band will move east of central NC through mid to late morning. Dew points in the upper 50s to lower 60s are expected by afternoon, while temperatures reach into the mid to upper 70s. If destabilization can occur, models are hinting at upwards of 500 to 1000 J/kg of MLCAPE developing across areas south and east of Raleigh Saturday afternoon. Given the expected upper forcing, there is a good chance for a band of showers and scattered storms to slide down from VA and move ese across central NC through Saturday evening. Shear parameters are pretty potent, with bulk-layer shear of ~60 kts expected Saturday afternoon. While simulated hodographs are largely straight amongst models, the latest HREF does indicate some weak clustering of mid-level helicity swaths in the Sandhills/Coastal Plain. All in all, think the overall severe potential is low, but if any stronger storm can develop there is plenty of strong kinematics to work with and thus can't rule an isolated stronger/organized storm (primary concern would be hail if anything at all).

Any lingering showers/storms should sweep south of our area by Saturday night. A sfc cold front will then sweep across the area late Saturday night/early Sunday morning drying things out. Overnight lows in the mid to upper 40s are expected.

LONG TERM /SUNDAY THROUGH THURSDAY/

As of 400 AM Friday...

Sunday will turn sunny and cooler with NW flow aloft and as surface high pressure builds in from the west. High temperatures will range from 60 in the far NE to upper-60s in the far SW which is still slightly above normal. The cool surface high will be centered over the Mid-Atlantic on Sunday night and with decent radiational cooling lows should be in the mid-to-upper-30s in many areas. As the high moves east and offshore on Monday, high temperatures will turn a couple degrees warmer on average and lows Monday night will be in the 40s. Clouds will increase on Monday night as the flow aloft turns southwesterly ahead of the next shortwave trough moving across the MS Valley.

A warm front will lift through the area on Tuesday, and isentropic upglide will result in persisting cloud cover and a chance for light rain. Meanwhile a deeper mid-level low/shortwave will move from the Northern Plains to the Upper Great Lakes and southern Canada from Tuesday through Thursday. However, there continue to be significant differences in the model guidance, with the 00z ECMWF depicting a more progressive system that drags a cold front through central NC early Wednesday, while the 00z GFS holds back the low and doesn't bring the cold frontal passage until early Thursday (Thanksgiving Day). In either case, rainfall amounts look fairly light with ensemble means around a tenth to quarter inch. And it doesn't appear rain will be much of an issue on Thanksgiving other than perhaps some lingering light rain in the morning if the GFS and some of its ensembles verify. Instability doesn't look too impressive either, especially with the timing of the cold frontal passage being early either day in the two models, but this could change and the mid- level flow certainly looks strong. Temperatures will also depend on the timing of the front, but for now the forecast calls for highs increasing to upper-60s to mid-70s by Wednesday, then dropping to the mid-50s to lower-60s by Thursday.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

As of 542 AM Friday...

12Z Update: MVFR to IFR ceilings and fog/visbys persist this morning. Expect light rain to continue east and impact KFAY/KRDU/KRWI the next few hours before a lull in rain this afternoon and evening. Sub-VFR ceilings will likely hold into the afternoon/evening hours. Additional showers will then fill in from west to east overnight through Saturday morning.

Largely VFR conditions continue across central NC early this morning, although MVFR ceilings have arrived at KFAY recently. Expect conditions to deteriorate at all TAF sites near sunrise as deeper low-level moisture (and some light rain) move across central NC through Friday afternoon. Fog and reduced visibilities are also likely at KINT/KGSO and KRWI later this morning. Any lingering sub- VFR ceilings/fog should lift by Friday evening. Additional light rain showers will be possible Friday night.

Outlook: Additional rounds of light rain and low-level cloudiness will be possible Friday night into Saturday. A front will sag into central NC on Saturday, continuing the chance for unsettled weather with perhaps a few thunderstorms Saturday afternoon. The front will clear south of our area Sunday, with dry VFR weather returning early next week.

RAH WATCHES/WARNINGS/ADVISORIES

None.