textproduct: Raleigh

WHAT HAS CHANGED

* Nothing appreciable.

KEY MESSAGES

As of 127 AM Thursday...

1) Chilly with widespread rain Friday night and Saturday as a deepening surface low lifts along the NC coast.

2) Expect moderating temperatures and another chance of rain by mid- week.

DISCUSSION

As of 245 PM Thursday..

KEY MESSAGE 1... Chilly with widespread rain Friday night and Saturday as a deepening surface low lifts along the NC coast.

Overview: A surface low will develop over FL on Friday, and shift newd off the Southeast US coast Fri night. A secondary inland low will lift newd across the Southeast US along the front Fri night/early Sat. The inland low should shift offshore on Sat as the coastal low deepens and lifts along the Carolina coast, but model solutions vary on whether the two will merge or remain separate with the coastal low remaining dominant and deepening while the secondary low shears out along the front. Regardless, the dominant low will rapidly deepen as it continues newd off the mid-Atlantic and New England coasts Sat night and Sun. Aloft, a srn stream s/w low will move inland over the nrn Baja Thu night, then track ewd across the srn Plains Fri and along the Gulf Coast and across the Southeast US Fri night. Meanwhile, a nrn stream s/w will drop swd across the Plains Fri night and across the MS Valley on Sat as it swings about the parent low over Ontario/Quebec, amplifying the longwave trough in the process. The nrn stream s/w will continue ewd across the Appalachians and mid-Atlantic/Carolinas Sat night and offshore Sun.

Precipitation: There may be some early shower activity across the far srn Coastal Plain Fri night, but confidence in that remains low at this time. The better chances for rain to begin overspreading the area from the south/southwest will be Friday night (possibly late), though exact timing varies. Fairly confident the onset will be stratiform in nature, possibly remaining stratiform across much of central NC throughout the day as the surface low and front stay to the south and east of the area with central NC on the cool, mostly stable side of them. However, forecast soundings from the NAM and GFS do show some very limited, elevated instability, and hi-res model guidance indicates some embedded showery character to the simulated reflectivity, mainly across the southern half of the area. Do not expect much if any thunder, but best (slight) chance will be closest to the coast (extreme srn Sampson County) in closest proximity to the low. There will likely be a wide range in over all rainfall totals for the event, with some continued uncertainty. For now, totals could range from quarter to half an inch over the northwest Piedmont to around an inch over the srn Coastal Plain.

Temperatures: With the current track of the low to the east, expect a continued feed of cool, dry air from the nne into the area on Sat. Combined with the expected precipitation on Sat, diabatic cooling could result in temperatures holding nearly steady or falling across the Piedmont during the day. Highs are expected to be well below normal, mainly peaking in the 50s, perhaps reaching 60 degrees in a few spots closer to the low/front (15-20 deg below normal). Rain should exit the area Sat evening, with skies clearing out through the night. With the cold air expected to spill over the mtns in the wake of the low Sat night, lows should drop into the upper 30s to mid 40s. Winds may remain a little stirred overnight with the cold air advecting in which, in addition to the potential lingering clouds in some spots, should limit the degree of radiational cooling. Below to well below normal temperatures will continue into Sunday, but with plentiful sunshine and dry weather, expect highs in the mid to upr 60s and lows generally in the low to mid 40s.

KEY MESSAGE 2... Expect moderating temperatures and another chance of rain by mid-week.

After cooler temperatures over the weekend, with highs in the 60s, high temperatures will moderate on Monday, returning to near normal values, before rising a few degrees above normal for Tuesday, Wednesday, and Thursday. As for the next chance of rain, there are definite timing differences between varying models, but it appears that a front should at least approach the region by the middle of the week. This should bring a chance for showers and at least a slight chance of thunderstorms on Wednesday and Thursday.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

As of 215 PM Thursday...

VFR conditions, but with periods of multi-layered, VFR ceilings beneath an energetic srn stream jet, are forecast through 18Z Fri. Those VFR ceilings, possibly as low as 5-6 thousand ft AGL, may be accompanied by light showers at FAY tonight, as a reinforcing front and brief increase in nly/nely surface winds/gusts progress across cntl NC.

Outlook: Rain and flight restrictions, lowest and longest at FAY/RWI/RDU, will accompany an area low pressure forecast to track along the coast of the Carolinas late Fri night-Sat.

RAH WATCHES/WARNINGS/ADVISORIES

None.