textproduct: Raleigh

WHAT HAS CHANGED

* Increased Fire Danger Statement in effect for Saturday for portions of central NC

KEY MESSAGES

As of 151 PM Friday...

1) Well above normal temperatures continue through Saturday, with a noticeable cooldown thereafter. Increased Fire Danger Statement in effect for portions of central NC on Saturday.

2) Rain chances remain in place for Saturday afternoon into Sunday , although rainfall amounts still appear to be light and not enough to mitigate the ongoing drought concerns.

3) Frequency of rain events increases Wed through the forecast period, but low forecast confidence on timing and amounts.

DISCUSSION

As of 151 PM Friday...

KEY MESSAGE 1... Well above normal temperatures continue through Saturday, with a noticeable cooldown thereafter into early next week. Increased Fire Danger Statement in effect for portions of central NC on Saturday.

Broad mid level ridging across the southeastern CONUS, along the the presence of a stalled frontal boundary across the Mid Atlantic, will allow for above normal temperatures across the region through Saturday. Afternoon highs today remain on track to reach the mid/upper 80s, with some spots in the Sandhills and southern Coastal Plain taking a run at 90 late this afternoon.

The stalled boundary to our north will slowly sag south tomorrow, yielding another day of well above normal temperatures in the mid/upper 80s, perhaps around 90 in the south. Pre-frontal breeziness and deep BL mixing will allow dewpoints to mix during the afternoon hours, with RH values dropping to around 25-30 percent. Winds will be strongest across the Sandhills and southern Coastal Plain which will be co-located with the lowest RH values. As such, an Increased Fire Danger Statement will be in place for those areas from late morning through early evening Saturday.

The front itself is not forecast to make its way through central NC until late Saturday night/Sunday morning, after which point cooler northeasterly flow will take hold over the area. Look for highs on Sunday to only reach the mid 60s in the northern Coastal Plain, while holding strong in the mid/upper 70s in the southwest Sandhills.

KEY MESSAGE 2... Rain chances remain in place for Saturday afternoon into Sunday, although rainfall amounts still appear to be light and not enough to mitigate the ongoing drought concerns.

The cold front that will usher in much cooler temperatures on Sunday is forecast to move through central NC late Saturday into Sunday morning. While there are certainly several ingredients coming into play that will bring us some much needed rainfall, they could be better. A modest amount of moisture advection will take place ahead of this front with PW's climbing to around 1.55" (well above normal for late April), although much of that advection will take place above the boundary layer as dewpoints will only make it into the lower 60s. In addition, the timing of the frontal passage will be well after peak heating and instability will be lacking at the time of FROPA. An area of pre-frontal showers appears likely from early afternoon onward across the western Piedmont as a weak pre-frontal shortwave sweeps through the area, with rain chances eventually increasing elsewhere by mid afternoon/early evening coincident with the frontal passage itself. While PoPs will be quite high (80-90 percent), QPF looks to remain low for the reasons outlined earlier. HREF LPMM suggests some spots could see anywhere from a quarter to half an inch, perhaps higher if a bit of training occurs, but this does not appear to be a widespread beneficial drought-ending rain event by any stretch of the imagination. Rainfall likely to linger through the overnight hours into early Sunday before tapering off from west to east Sunday afternoon.

KEY MESSAGE 3...Frequency of rain events increases Wed through the forecast period, but low forecast confidence on timing and amounts.

Precipitation chances continue to trend down for Tues as models are trending stronger with the ridge axis in place ahead of perturbed flow and narrow mid-level moisture axis that spreads into the Mid- Atlantic on Tues. This initial wave does however work to begin breaking down the ridge into a quasi-zonal flow regime and near- normal PWAT values.

Waves of perturbed flow will ripple across the Southeast and Mid- Atlantic Wed through the forecast period with each bringing the potential for much needed rainfall; although, none look to bring any significant rainfall to the region. Behind a warm frontal passage Tues into Wed, marginal instability may be in place to help fuel diurnal showers/storms each afternoon. Unfortunately, outside of any organization along any upstream MVC's, this may result in more hit- or-miss variety within the rainfall footprint.

There may be some hope for a more appreciable precipitation event just beyond the forecast period into early May. There is a signal within ensemble guidance for a stalling frontal boundary over the Mid-Atlantic and weak low pressure spreading more steady rainfall along and north of its track. Member MSLP tracks range from the through the Ohio Valley to over the Carolinas, so forecast confidence remains low at this time.

AVIATION /17Z FRIDAY THROUGH TUESDAY/

As of 100 PM Friday...

TAF period: High confidence in VFR conditions over the next 24 hours. Gusts so far today have been more isolated than forecast, so lowered the wind speed during the day and decided to go with a single line in the forecast, not differentiating between the lower wind speed overnight. Some mid level clouds may make it from the mountains to INT/GSO, otherwise a thin layer of high clouds is all that is expected.

Outlook: VFR conditions are likely to continue Saturday afternoon, but restrictions are expected to develop with showers and isolated thunderstorms as a cold front moves through central North Carolina Saturday night. IFR ceilings will be possible at all sites (with FAY the least likely) late Saturday night into Sunday morning, with a return to VFR conditions Sunday afternoon as rain moves east. Some model guidance indicates wind gusts could be as high as 20-25 kt late Saturday afternoon as the cold front moves through. Another round of showers and restrictions will be possible with an additional front on Tuesday.

RAH WATCHES/WARNINGS/ADVISORIES

None.