textproduct: Raleigh

WHAT HAS CHANGED

As of 300 PM Sunday...

* Pre-frontal storms with locally damaging wind gusts will progress ewd and out of RAH's Coastal Plain through 20Z.

KEY MESSAGES

As of 300 PM Sunday...

1) Pre-frontal convection with locally damaging wind gusts will progress ewd and out of RAH's Coastal Plain through 20Z.

2) Widespread frost possible for much of central North Carolina Wednesday and Thursday morning.

3) Dry conditions expected to intensify fire weather concerns through the week.

DISCUSSION

As of 300 PM Sunday...

KEY MESSAGE 1...

A band of pre-frontal convection, extending at 19Z through the far ern reaches of RAH's Coastal Plain from near ASJ to PGF to EYF, will continue to pose a risk of 35-50 kt surface wind gusts and small hail as it progresses through a diurnally-destabilized and relatively well-mixed, steep low-level lapse rate environment over ern NC. The airmass between that pre-frontal convective band, and a lead surface cold front now progressing slowly across the nrn NC Piedmont, is one that will remain only weakly unstable beneath a denser mid/high-level cloud canopy and light, stratiform rain/sprinkles. That environment will support a mix of the aforementioned stratiform rain and less-vigorous convection with gusty winds to 30-35 kts, along and ahead of the cold front as it progresses sewd and across the forecast area through this evening. That lead front, whose wrn portion has slowed as it settled through the nw Piedmont during the past few hours, will likely get overtaken by a closely-following and reinforcing front, whose leading edge and surge of markedly drier air and wnwly momentum has progressed to near MWK to UKF.

KEY MESSAGE 2... Widespread frost possible for much of central North Carolina Wednesday and Thursday morning.

After this afternoon's cold front and Monday night's cold front, high pressure will move over the Great Lakes Tuesday and over the Northeast on Wednesday. While lows will fall into the 40s tonight and Monday night, at least the northern half of the forecast area is likely to drop into the 30s both Tuesday night and Wednesday night. The current forecast calls for the sustained wind to remain between 5 and 10 mph each night, which would not be ideal for radiational cooling to occur. Still, there will be the potential for frost formation both nights. By Thursday night, low temperatures everywhere will return to the 40s and 50s.

KEY MESSAGE 3 ... Dry conditions expected to intensify fire weather concerns through the week.

After this afternoon's cold front and Monday night's cold front, high pressure will move over the Great Lakes Tuesday and over the Northeast on Wednesday. The resulting north-northeasterly wind will bring drier air into the region, and other than a slight chance of showers across Sampson County late week, there is no rain in the forecast after today. This will worsen the ongoing drought and likely lead to additional fire weather concerns. While wind gusts shouldn't be more than 15-20 mph, the minimum RH values on Tuesday and Wednesday will be somewhere between 20-35%, with minimum RH values later in the forecast still dropping as low as 30%.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

As of 215 PM Sunday...

A band of pre-frontal convection, extending at 18Z from near IXA to RWI to CTZ, will probably continue to intensify and favor 35-50 kt surface wind gusts as it progresses through a further diurnally- destabilizing environment over ern NC. A mix of less vigorous convection and stratiform rain with temporary flight restrictions, and also gusty swly surface winds, will otherwise continue throughout cntl NC along and ahead of a couple of cold fronts that will progress sewd and across the forecast area through this evening. A short period of nwly gustiness to around 30 kts will be possible as the initial surge of cooler and drier post-frontal air arrives this evening, with surface winds otherwise around 10 kts or less through the end of the 18Z TAF period.

Outlook: A couple of areas of continental Polar high pressure, and associated dry air, will favor VFR conditions in cntl NC through the upcoming week.

RAH WATCHES/WARNINGS/ADVISORIES

None.