973 FXUS62 KRAH 111113 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 713 AM EDT Fri Apr 11 2025 .SYNOPSIS... Low pressure at the surface and aloft will move slowly across NC and VA through early Saturday. Canadian high pressure will then build across and offshore the Middle and South Atlantic later Saturday through the rest of the weekend, ahead of a warm front that will move across the region on Monday. && .NEAR TERM /THROUGH TONIGHT/... As of 445 AM Friday... * Stratiform rain this morning, followed by efficient hail-producing and generally low-topped showers and thunderstorms this afternoon- early evening * Large, severe-sized hail will be favored over the ern half of NC, roughly along and east of a line from RCZ to RDU to IXA. Within a mid/upr-level trough that will progress slowly ewd and across the Middle and South Atlantic, a cyclone will develop and deepen across VA and nrn NC, with an associated pocket of minus 24- 25C temperatures at 500 mb, through 12Z Sat. A series of at least three, distinct vorticity maxima evident in regional radar and water vapor satellite data now over the NC Sandhills, ern TN/KY, and wrn TN/KY, respectively, will rotate through the ern periphery of the developing cyclone and across cntl and ern NC through this evening. At the surface, a 1013 mb frontal low now over the srn NC Piedmont will deepen 4-5 mb while tracking generally enewd and through cntl and nern NC through this afternoon, then across Tidewater VA, the Chesapeake Bay, and the DelMarVa tonight. Following, ~1026 mb Canadian high pressure will build sewd and across the MS Valley. Widespread, multi-layered overcast, and stratiform rain accompanying a lead, convectively-amplified vort max now centered over the NC Sandhills, will maintain cool and stable conditions over cntl NC through mid-morning. A band of convection may develop immediately ahead of this feature and across ern NC and sern VA by late morning-early afternoon. At the same time and more influential to cntl NC, south to north lifting and scattering of the low overcast will likely occur along and immediately following the passing frontal low, with associated warming surface temperatures through the 60s, to near 70 F from MEB to GSB and points swd. Associated weak destabilization up to 750- 1000 J/kg will result, as that boundary layer warming occurs beneath the aforementioned pocket of cold and cooling temperatures aloft, and related steep mid-level lapse rates of ~7 C/km. The presence of strong, ~40-50 kts of swly mid-level flow maximized over ern NC will provide ample shear and elongated hodographs that will favor splitting of generally low-topped cells. Large hail will be the associated primary severe hazard where that associated shear and instability parameter space is most likely to be maximized - roughly along a line from RCZ to RDU to IXA, coast-ward. Already low freezing levels that were observed at 6200 ft AGL at GSO last evening will further lower within the aforementioned steep lase rate environment, as temperatures aloft cool through this evening. Associated thermal and instability profiles will be favorable for the production of small (pea) hail, some that may cover the ground, in even shallower and more weakly-sheared cells throughout cntl NC through this evening. While the threat of convection will diminish after sunset, a deformation band of saturation ~4-6 thousand ft deep, accompanying the passing low pressure, will probably maintain occasional light rain over the far ne Piedmont and nrn and cntl Coastal Plain through Sat morning, with low temperatures mostly in the mid-upr 40s. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... As of 327 AM Friday... The upper system will slowly migrate offshore Saturday into Sunday. Models continue to indicate that enough upper forcing and anomalous moisture will hang around to promote widely scattered showers at times through Saturday evening (highest POPs in the east). Rain chances will end near sunrise Sunday morning as the system pulls further offshore. Given the persistent cloud cover, cooler conditions are expected Saturday with area-wide mid to upper 50s expected. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 237 AM Friday... Sunday through Monday: Dry nwly flow aloft on Sunday, followed by zonal mid-level ridging on Monday will promote dry conditions both days. After a cooler day in the upper 60s Sunday, temperatures will rebound back into the upper 70s to lower 80s Monday under ridging aloft. Tuesday through Thursday: Flow turns more sswly ahead of our next trough on Tuesday, but models have trended a bit faster with our next cold front. As such, latest guidance suggest a bit cooler temps are possible on Tuesday with highs across the northwest in the lower 70s (mid to upper 70s across the southeast). The frontal passage still appears to be mostly dry, but enough ensemble members predict some chance for measurable rain Tuesday afternoon to keep a mention of slight chance pops for those along and east of US-1. It should not amount to much though. Post-frontal cool mid to upper 60s temperatures are then expected Wednesday. Beyond Wednesday, models hint at another short-wave riding through the central US which could bring rain chances back to our area late next week. && .AVIATION /11Z FRIDAY THROUGH TUESDAY/... As of 710 AM Friday... LIFR-IFR ceilings, mostly MVFR visibility restrictions, and a band of initially stratiform rain, will accompany a passing area of low pressure across cntl NC this morning. Precipitation will then become increasingly-convective with daytime heating this afternoon through early evening, beneath cold temperatures and forcing for lift aloft. Ceilings will otherwise gradually lift to MVFR from south to north in between convection this afternoon, and probably to VFR at FAY and RWI. Redevelopment and swd expansion of IFR-MVFR ceilings and patchy light rain, in continued cool and moist nly flow around low pressure that will track slowly off the srn Middle Atlantic coast, will result over particularly the ern half of cntl NC tonight-early Sat. Outlook: MVFR ceilings and some shallow showers are expected to linger through Sat, especially at RWI and potentially at RDU/FAY. A return to VFR is expected Sat night. Gusty southwesterly winds 20 to 30 kts and low-level turbulence will be possible on Mon ahead of dry cold frontal passage on Tues. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...Luchetti LONG TERM...Luchetti AVIATION...MWS/Swiggett