Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 040740 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 340 AM EDT Sat Apr 04 2020 .SYNOPSIS... Surface high pressure will settle across the area today. The high will move offshore late Sunday, which will allow a weak surface front to move into the area Sunday night before stalling and eventually washing out early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 340 AM Saturday... With the low pressure system over the western Atlantic finally moving out to sea, ridging aloft will be allowed to build east across the region. Meanwhile downstairs, weak surface high will settle over the southern Mid-Atlantic States. The associated N-NELY low-level will advect some slightly cooler air into the area today, as well as an alto-cumulus cloud layer into NE portions of the forecast area during the afternoon. Otherwise, expect mostly sunny conditions again today with afternoon highs a touch cooler than yesterday; ranging from lower/mid 60s NE to lower 70s SW. Weak shortwave impulses traversing the SE US will result in occasionally fair to mostly clear skies overnight. Otherwise, it will remain dry. Lows in the 40s, to near 50 SW. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 340 AM Saturday... Central NC will remain under the influence of the broad upper ridge in place across much of the southern CONUS. The area of weak high pressure centered over the area to start the day will move east and offshore by the afternoon and evening. This will allow a weak front to move into northern portions of the area during the early evening, where it is then forecast to stall out overnight. Despite the fact that moisture, lift, and instability are all limited, a majority the deterministic guidance, including the hi-res CAMs, indicate some isolated shower activity INVOF the northern Piedmont and northern coastal zones late Sunday afternoon and into Sunday night. Thus, had added an isolated PoP. Otherwise, with no significant airmass change on Sunday, temps will comparable to Saturday, though warmer across the NE zones. Highs in the upper 60s to lower 70s. Not as cool overnight, with lows in the lower to mid 50s. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 330 AM Saturday... Upper level ridging will continue to build east of the Rockies early next week as an upper-trough inches ashore along the western CONUS before nearly stalling across the Baja California Coastline through mid-week. This wave will begin to interact with a developing northern stream shortwave mid to late week, finally ejecting east as a developing upper-trough sometime in the Friday - Saturday time frame. A backdoor cold front will dip toward but likely remain just north of the VA/NC border monday night before spreading back north as a warm front on Tuesday. This in response to surface high pressure drifting southeast off GA/SC coast, aiding in the re-establishment of sustained southwesterly flow across the central Carolinas early Tuesday afternoon. This will result in a gradual warming and moistening trend through the middle of the work-week with POPs beginning to increase slightly as a series of weak pacific born mid- level impulses round the apex of the southern stream ridge. At this point, a still moisture starved airmass will likely only support isolated to widely scattered shower coverage, with best distribution likely occurring both Monday and Tuesday afternoons. Ample capping should be efficient enough to limit both coverage and shower intensity for the most part during this time frame. A drying trend will commence mid to late week as the mid-level ridge breaks down in response to the approaching trough from the west. Uncertainty, especially beyond the Thursday period, remains extremely high at this time thanks to rather large disagreements in model output solutions in the Day 6/7 period. Most of these differences stem from how each guidance package handles the Baja Low. For instance, the GFS never truly cuts the low off from northern stream influence, helping to encourage the further interaction with the developing mid-level shortwave ejecting both features east as a much stronger upper-trough feature. Meanwhile, ECMWF guidance completely cuts the low off, ejecting the northern stream jet streak east through the Great Lakes without the cutoff low over southern CA. This will still result in a cold frontal passage, but a much weaker and drier one thanks to forcing remaining further north. With uncertainty remaining so high, have trended POPs down and elongated their influence mainly through the late Thursday through Friday time period for now. Either way, a brief wet period ahead of a likely strong FROPA will occur, followed by a much cooler and drier airmass which should settle into place as we begin to progress into next weekend. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 200 AM Saturday... 24 Hour TAF Period: Surface high pressure settling over the area combined with dry NW flow aloft will result in VFR conditions through the period(high confidence). Gusts today will be minimal, with winds generally 5 to 10 mph, becoming E-NELY during the afternoon and evening. Outlook: VFR conditions and dry weather are expected through Sunday. Only slight chances for showers will increase early next week, along with potentially minimal sub-VFR conditions. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...CBL LONG TERM...JJM AVIATION...CBL/Badgett

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