197 FXUS62 KRAH 170614 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 214 AM EDT Thu Apr 17 2025 .SYNOPSIS... Cool high pressure over the area will push slowly offshore today through Friday, bringing a warming trend through the weekend and into early next week. A frontal system will approach from the west Monday, then stall out and linger over the region through Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 215 AM Thursday... * Frost Advisory in effect until 8 AM this morning for patchy frost in rural areas of the Piedmont. * Seasonable today, not as cool tonight. The center of surface high pressure will shift across the Mid- Atlantic this morning and briefly settle just off the NC coast by this afternoon. Confluence aloft will help strengthen the surface high to around 1030mb by Fri morning. Little modification to the airmass in place will result in similar temperatures today compared to Wed (upper 60s to low/mid 70s). An elevated warm frontal zone centered around 500mb will bring an increase to multi-layered cloudiness late this afternoon through the overnight hours. With the center of the surface high building just off the coast, there will be very shallow moisture advection within the light southeasterly surface flow off the Atlantic. For now, point soundings suggest this layer will only a few hundred feet thick with very dry air aloft and may only result in dew at the surface; however, shallow ground fog and/or a low stratus deck can`t be ruled out. Overnight lows will settle in the mid/upper 40s to around 50, but may be a category or two warmer if a low stratus deck forms. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 215 AM Thursday... * Breezy southwesterly winds bring a pattern change to above normal temperatures. A series of shortwaves over the Intermountain West and just off the CA coast on Thurs will combine and favor a more amplified mid/upper level pattern through Fri. Downstream amplification will result in an anomalous shortwave ridge to shift and further amplify from the Lower MS Valley to over the Southeast by 12z Sat. This process will shift the center of the low/mid-level anticyclone from over the Gulf to over and just off the Southeast Coast in the western N. Atlantic; this will favor deep warming south-southwesterly flow to begin a pattern change of anomalous warmth heading into the weekend. Skies should be mostly clear with only wisps of cirrus clouds through the afternoon, which should not impact diurnal heating and allow temperatures to rise well into the 80s (up to 10 degrees above normal). A tightening pressure gradient at the surface and increasing momentum aloft should support low-end winds 10 to 15 mph with frequent gusts up to 25 mph through the afternoon. Overnight stirring and anomalous warmth will keep overnight lows mild and only fall to the low 60s (15 degrees above normal). && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 200 AM Thursday... We have high confidence in warm and dry weather through at least Easter Sunday night. Moderating but still-mild temps are expected early next week with the arrival of rain chances Mon/Tue, perhaps lasting through Wed across southern sections, but details are highly uncertain. Sat-Sun night: The low level anticyclone will settle just off the Southeast coast as strong and deep mid level ridging holds over the Southeast states and Carolinas, ensuring a steady S and SW low level flow topped by warm and stable mid levels. As this warmth aloft inhibits deep convection and as the stream of high PW holds to our W and NW, we`re likely to stay dry through the weekend. Models are settling toward greater commonality in showing an anticipated backdoor front just barely nudging into our NE late Sun, propelled by a SE Canada polar low and corresponding cool surface high extending down into the Mid Atlantic coast. This feature appears fleeting, leaving as quickly as it arrives given the progressive nature of its driving mechanisms, so expect little more than some enhanced cloudiness and perhaps briefly lower dewpoints in our far NE. Models have been consistently clustered around projected warm low level thicknesses of 25-30 m above normal Sat and 30-35 m above normal Sun, and given lots of sunshine, we could easily overshoot NBM deterministic forecast temps. Expect warm highs in the mid 80s to near 90 both days. Lows will be mostly in the lower to mid 60s. Mon-Wed: Model solutions remain varied with the longwave pattern, but they generally depict the potent Plains low tracking into the W Great Lakes region by early Mon, then becoming a more open wave as it crosses SE Ontario and S Quebec through Tue and the Canadian Maritimes Wed, all the while slowly flattening the ridging over and off the Southeast/FL coast. At the surface, the corresponding surface cold front is projected to move into W NC Mon, with our area holding in the warm sector, favoring still-warm highs ranging from the low 80s NW (with increasing/thickening clouds) to upper 80s SE. Prefrontal scattered showers with some embedded thunder are expected to cross the CWA Mon afternoon through Mon night, and while coverage and amounts are highly uncertain, it doesn`t have the markers of a particular efficient rainmaker given the modest dynamic forcing for ascent, so any rainfall amounts should be on the low side. The cold front should ease ESE into the forecast area late Mon into Tue, settling over our central or SE sections as weak high pressure builds over WV. As this high weakens further while drifting into VA, models generally favor frontolysis, with the now-stationary front weakening considerably across our S Tue night/Wed, reasonable given the likely decrease in front-parallel mid level flow over the Mid South/Southeast/Mid Atlantic regions. Will retain climo-leaning chance pops in the afternoon Tue areawide and across the S Wed for now, with continued above normal highs in the upper 70s to lower 80s as we remain shut off from any source of cooler air. -GIH && .AVIATION /05Z THURSDAY THROUGH MONDAY/... As of 100 AM Thursday... VFR conditions are expected through the 24 hour TAF period. Light and variable winds tonight will continue through the early afternoon as surface high pressure slides across the region. Surface winds will become southerly by late Thurs afternoon as mid/high clouds begin to stream over the Mid-Atlantic. Outlook: Shallow moisture return early Fri morning (06-12z Fri) may result in a scattered low-stratus deck at FAY (20 to 40% chance) and RDU/RWI (15 to 25% chance). Strengthening LLJ of 35 to 45 kts may result in marginal LLWS at all sites Fri night. && .EQUIPMENT... KRAX will remain down due to a mechanical issue. Technicians are aware and will be on-site later today to perform unscheduled maintenance. A return service time is unknown until technicians can assess the situation. && .RAH WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 8 AM EDT this morning for NCZ007>009- 021>025-038>040-074>076. && $$ SYNOPSIS...Hartfield NEAR TERM...Swiggett SHORT TERM...Swiggett LONG TERM...Hartfield AVIATION...Swiggett EQUIPMENT...RAH