textproduct: Raleigh

SYNOPSIS

The wavering front remains in the vicinity of North Carolina through Monday - moving south across the area this afternoon, remaining to the south tonight and Sunday, then rising north Sunday night before a strong cold front sweeps across the state on Monday. The rest of the week will be dry with cooler than normal temperatures.

NEAR TERM /THROUGH TONIGHT/

As of 1240 PM Saturday...

The temperature seesaw continues across central North Carolina. Today's normal high at RDU is 53 degrees - the highs the last three days have been 71, 72, and 59, with a forecast high back into the upper 60s today. The rollercoaster with the temperatures is courtesy of a front that continues to wobble across the region, currently along the VA/NC border but expected to drop back to the south again during the day. A surface high is currently centered over Ontario and a ridge will extend south into North Carolina through tonight, bringing additional northeast flow into the region. Skies should be mostly sunny through the afternoon, but sky cover will increase after sunset from northwest to southeast. The forecast lows tonight did not change in most locations, only one or two degrees in other locations, and still range from near freezing in the northeast to the mid 40s in the southwest.

SHORT TERM /SUNDAY AND SUNDAY NIGHT/

As of 1240 PM Saturday...

High pressure will be centered over the Delmarva Peninsula Sunday morning, and light easterly flow will veer towards the southeast as the high slowly moves offshore. Meanwhile, low pressure over the central Plains will deepen as it reaches Chicago Sunday evening and moves over Lake Huron by Monday morning. In-situ CAD appears likely to develop, especially with a strong inversion developing in the lowest mile of the atmosphere. Blended the NBM and the 25th percentile of the NBM, which dropped the high forecast for Sunday up to 5-7 degrees in some locations. Many locations across the VA/NC border are likely to remain in the 40s through the day, while the rest of the area will be in the 50s - a 5 to 20 degree drop in highs compared to today.

While a slight chance of rain will develop across the Piedmont late Sunday afternoon, a higher chance of rain will develop Sunday night as the wedge front moves back to the north across the state, putting central North Carolina back on the warm side of the boundary. This will also result in low temperatures likely occurring during the evening, with slowly rising temperatures after that. The lowest temperatures will likely range from the mid 40s in the north to the mid 50s in the south during the evening, but temperatures should be more uniform by sunrise Monday in the mid to upper 50s.

LONG TERM /MONDAY THROUGH SATURDAY/

As of 1240 PM Saturday...

* Strong gusty winds and above normal temps Mon ahead of a strong cold front that sweeps through late Mon

* Colder temps and blustery winds arrive for Mon night and especially Tue, when dry conditions and wind gusts may bring fire weather concerns.

* Moderating temperatures around midweek, but uncertainty around a possible late-week cold front

A tight pressure gradient will be in place ahead of the Mon cold frontal passage, with west-southwest winds still expected to be in the 30 to 35 mph range. Highs on Mon are likely to be the warmest of the period with low to mid 60s across the west and upper 60s to low 70s in the east. While the cold front or its pre-frontal trough may move through in the mid to late afternoon hours, the bulk of the colder air will not filter in until Mon night, when cold high pressure builds into the Southern Plains. There still appears to be limited rainfall with the front, with some areas staying dry and only a few hundredths of an inch elsewhere. Temperatures will crash Mon night to Tue morning in the 20s, with wind chills from the mid teens to lower 20s, so it will be quite the change from our warm holiday stretch.

Tue looks to be the coldest day of the week so far, with low to mid 40s for highs and low to mid 20s for lows. Highs should moderate Wed as WSW winds take over but we are still below normal in the upper 40s to around 50. Fire danger concerns are still warranted Tue and possibly even into Wed as WNW to WSW surface winds of 15 to 30 mph are possible given the pressure gradient in place and RH levels well into the 20s with weak moisture return.

As we head into the latter part of the extended, uncertainty increases and forecast confidence decreases. Ensemble data differs in regards to a late-week cold front perhaps late Thu to early Fri, as well as a southern stream system that could bring rain on Sat. Some guidance keeps the front to the north, while other solutions bring is well into the Deep South. For now, a middle of the road approach would suggest a slight moderating trend with highs ranging from the upper 40s to lower 50s, cooler on Fri, with low-end rain chances Sat.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

As of 100 PM Saturday...

VFR conditions will prevail across central NC terminals through much of this afternoon and evening, with only high clouds overhead. Overnight, a lowering cloud deck will overspread the region from west to east as surface flow weakens and veers easterly. While all terminals are expected to stay dry until Sunday afternoon, there is a very low end chance for patchy light rain and drizzle. Confidence was not high enough to include them in this TAF package.

For the Triad region (KINT/KGSO), ceilings are expected to lower to MVFR after 06z, deteriorating further to IFR towards daybreak Sunday morning as ceilings fall at or below 1kft. IFR conditions are expected to persist through much of the late morning and early afternoon hours. Farther east, KRDU will see ceilings lower into MVFR late Sunday morning, while KRWI and KFAY remain VFR overnight with MVFR ceilings developing closer to midday Sunday. Winds will remain light and generally easterly through the period.

Outlook: Conditions are expected to further deteriorate after the 18z Sunday TAF period, with expanding IFR to LIFR ceilings and increasing potential for drizzle or light rain late Sunday afternoon into Sunday night, especially across the Piedmont impacting the 4 northern terminals. Gusty southwest winds are expected to develop ahead of the frontal passage Mon morning (gusts 15-25 kts), then veering to a north-northwesterly behind the front and remain gusty Mon afternoon into Tuesday. Generally quiet weather is expected Wednesday and Thursday before another front moves across the region late week.

RAH WATCHES/WARNINGS/ADVISORIES

None.