textproduct: Raleigh

WHAT HAS CHANGED

* Lesser shower chances in the south today, nothing expected north.

* Rain chances increasing for Monday.

KEY MESSAGES

As of 205 AM Saturday...

1) Scattered showers and isolated thunderstorms expected mainly south of Charlotte to Fayetteville today. Drier air will be punching in from the north during the day keeping rain chances low north.

2) A wavy frontal zone will bring a chance for showers/storms Thursday into Saturday to the Carolinas.

DISCUSSION

As of 205 AM Saturday...

KEY MESSAGE 1... Scattered and isolated thunderstorms expected mainly south of Charlotte to Fayetteville today. Drier air will be punching in from the north during the day keeping rain chances low north.

The main synoptic front extended from central KY SE across southern NC and offshore this morning. The anomalous mid/upper ridging remained in place from MN to NC, with low pressure over the NE and higher pressure near the Gulf Coast. Central NC remains on the dry side of the upper ridging with the deepest moisture remaining from TN SE across SC into far SE NC. The boundary will try to move a bit this morning into southern NC, but a quick moving wave of low pressure will move from the TN Valley currently to far SE NC by late morning. This will pull the front back southward to the NC/SC boarder region around 18z, then on to the south and southeast across SC thereafter. This will keep the better shower chances from Charlotte to Fayetteville this morning. Then the better chances will shift south and away from our southern counties between 18z and 22z. This is favored by most guidance including the latest hi-res modeling. Unfortunately for those that need rainfall, the QPF appears to be 0.25 or less in the south with some local 0.50 to possibly 1 inch localized amounts near the NC/SC border region. To the north of Charlotte and Fayetteville, some lighter showers are possible, but QFP will be 0.1 or lower with nothing expected over the Triad and Triangle northward.

It will also be warmer today as the drier air comes in this afternoon dropping dew points into the 40s/50s in all but the far south between 18z and 00z/tonight. Highs may reach or exceed 85 for much of the northern and eastern zones depending on the thickness of the high cloudiness.

Some clearing is expected from the north and east tonight as the higher pressure to the north builds in. Winds will be gusty with the backdoor front within a few hours of sunset, with gusts to 20-25 mph expected. Lows tonight will dip into the lower 50s NE ranging to near 60 SE. Skies will average mostly cloudy with plenty of lingering mid/high clouds that will get pushed southward late tonight.

KEY MESSAGE 2... A wavy frontal zone will buckle northward once again on Mon, but rainfall amounts appear limited west of the I-95 corridor.

A high-latitude omega-blocking pattern will prevail through Wed before beginning to break down on Thurs with a highly anomalous and persistent mid/upper-lvl ridge extending into central Canada which will be bookended by a pair of mid/upper-lvl lows over the northern Rockies and the Canadian maritimes. This stagnant pattern will favor a series of shortwaves to lock-in mean troughing over the Northeast and off the Mid-Atlantic Coast and push several reinforcing cold fronts into the area potentially through Wed.

Deep layer moisture along and north of the wavy frontal zone to our south will once again buckle northward ahead of yet another cold front on Mon. An added complication highlighted in deterministic guidance suggests a weak disturbance ejecting underneath the high- latitude omega block may bring increasing cloud coverage as well as some virga and very light rain Mon morning. Better chances for showers will likely be over the upslope terrain in western NC with orographic forcing overcoming meager instability, as well as the Coastal Carolinas.

Localized enhancements to precipitation coverage appears possible along the track of any storm-scale MCVs, but predictability on these meso-gamma to meso-beta features is nearly impossible with any degree of confidence at this time range. With that said, the latest ensemble probabilities of measurable rain continue to increase Forecast rain totals appear fairly limited for the Piedmont, however, there are 20 to 45% probabilities for >= 0.5" for the Coastal Plain and Sandhills from the 12z LREF as well as the 18z GEFS, GEPS, EPS.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

As of 124 AM Saturday...

A front will bring a chance of showers and isolated thunderstorms with MVFR conditions, mainly from KCLT to KFAY southward today. Otherwise, a backdoor cold front will progress across the Middle Atlantic and through cntl NC Sat late today and this evening, when NE surface winds may gust between 20-25 kts. Otherwise, generally VFR cigs will continue today and tonight.

Outlook: Another frontal system will affect cntl NC with a chance of flight restrictions and showers/storms on Mon.

RAH WATCHES/WARNINGS/ADVISORIES

None.