textproduct: Raleigh

WHAT HAS CHANGED

* The chance of any meaningful/impactful rain through next week appears low.

KEY MESSAGES

As of 300 PM Friday...

1) More-seasonable temperatures return to central NC this weekend behind a backdoor cold front.

2) While the next best chance of rain will be mid to late next week, forecast confidence in specific timing and amounts --if any of consequence/benefit of the latter-- is low.

DISCUSSION

As of 300 PM Friday...

KEY MESSAGE 1... More-seasonable temperatures return to central NC this weekend behind a backdoor cold front.

A cold front is presently located across the lower OH valley and Mid- Atlantic region. Much of the model guidance depicts this front moving through in backdoor fashion overnight tonight and early Saturday, with 1034-mb cool surface high pressure extending down into the region through early next week. Ahead of the front, today will see our warmest day of the next seven days, with most locations in the lower 80s this afternoon. These highs should stay below records.

As the front moves through, some gusts out of the northeast will be favored Saturday morning and early afternoon, between 15-20 mph, diminishing by sunset. The main influence from the front will be more-seasonable temperatures in the middle 60s to around 70 degrees.

KEY MESSAGE 2... While the next best chance of rain will be mid to late next week, forecast confidence in specific timing and amounts -- if any of consequence/benefit of the latter-- is low.

"When in drought, leave it out," best summarizes this forecaster's skepticism in prospects of meaningful rain next week.

There remains considerable model spread and forecast uncertainty surrounding at least a couple of synoptic troughs in slowly progressive flow aloft across NOAM next week, during which time a persistent, blocking ridge over Europe may further slow the flow upstream across the N. Atlantic and US into next weekend. Within that slowly progressive to blocking pattern, NWP guidance indicate a tendency for the troughs to split across the lower mid-latitudes, which casts doubt in the degree of large-scale forcing for ascent that will be available over cntl NC.

The first of those slowly progressive troughs will likely be an aggregate of a couple of mid and upr-level perturbations now evident in GOES-E data along the Rio Grande Valley and another over srn CA, as they progress ewd and across and just offshore the South Atlantic coast by early next week. 12Z guidance has trended less amplified with this trough relative to previous forecast cycles. Another and initially more-amplified trough will follow and consist of a positive tilt trough now extending swwd from a vigorous, cold-core cyclone off the Pacific Northwest coast through multiple Pacific perturbations to near and northeast of HI. That trough appears increasingly-likely to split as it progresses into the ern US - not particularly favorable for lift and precipitation in cntl NC. 12Z guidance has trended a little quicker and more amplified in another trough forecast to progress across the CONUS late next week, which may offer another opportunity for lift across NC, but forecast confidence is even lower at that time range.

At the surface, the most dominant and highest predictability feature will be an area of high pressure that will extend across the Middle Atlantic, while weakening, through mid-week. With the aforementioned trend in 12Z guidance of a much less amplified trough aloft off the South Atlantic coast early next week, there has been a similar trend toward weaker surface low pressure there. The frontal zone accompanying the splitting trough mid to late week is slower and weaker in 12Z guidance, with weaker convergence/lift and preceding moisture transport across cntl NC.

The most predictable aspect of the sensible weather next week will be moderating and above average temperatures. While the probabilities for rain will increase by mid to late week, they are subject to the low confidence pattern of slowly progressive and splitting troughs that frankly do not appear to offer much hope of impactful rain at this time.

CLIMATE

Record High Temperatures:

October 30: KGSO: 84/2016 KRDU: 86/1996 KFAY: 87/1950

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

As of 725 PM Friday...

24 hour TAF period: High confidence VFR will prevail through the 24 hour TAF period, with an increase in mid and high clouds expected on Sat. Calm to light nly winds through early tonight will increase and shift to more nely in the wake of a backdoor front passage early Sat. As noted in the previous discussion, winds will increase just above the surface early Sat. This could lead to some marginal LLWS, but currently the magnitude looks to stay below criteria. Some gusts out of the NE Saturday morning could range from 15-18 kt, most favored at the eastern sites.

Outlook: VFR conditions should dominate through the middle of next week.

RAH WATCHES/WARNINGS/ADVISORIES

None.