Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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102 FXUS62 KRAH 040035 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 835 PM EDT Fri May 3 2024 .SYNOPSIS... A backdoor cold front will settle into north-central North Carolina tonight, where it will stall through Saturday night, then weaken and move northward into Virginia on Sunday. && .NEAR TERM /THROUGH TONIGHT/... As of 835 PM Friday... A backdoor cold front has moved into the extreme northeastern portion of the forecast area - KIXA had a wind shift from southerly at 6pm to easterly at 7pm. In addition, several sites across southeastern Virginia and northeastern North Carolina have had a shift to easterly wind with much cooler temperatures. Meanwhile, an area of showers and thunderstorms is moving to the north out of Person County, with an area of showers extending farther to the south where a differential heating boundary developed earlier. The chance for showers and thunderstorms should diminish through the evening, then rise again overnight as the back door front moves farther into the area. The location of the front and just how far southwest it moves could have a significant impact on overnight temperatures. The current forecast calls for temperatures in the low 60s across the northeast to the mid 60s in the southwest. In addition, an area of low stratus appears likely to move in behind the front. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 230 PM Friday... Aloft, the sub-tropical ridge will stall along the eastern seaboard through Sat night. A southern stream disturbance will move into the Southeast US on Sat, then lift newd through the area as a sheared out northern stream s/w moves through the OH Valley/Great Lakes Sat night. The sub-tropical ridge will shift offshore and breakdown Sun/Sun night as the disturbances move through the mid-Atlantic and Northeast US. Another southern stream s/w will develop over the southern Plains on Sun, then move eastward into the lower/mid-MS Valley Sun night. At the surface, as high pressure sits over the New England coast, the backdoor cold front is expected to stall over nrn/nern NC through Sat and into Sat night then lift northward late Sat night/Sun. The high should move eastward over the Atlantic as a low moves through the Great Lakes and into the Northeast Sun/Sun night. Precipitation/Convection: Still fairly high confidence/chances for showers and possible storms Sat and Sun. Best threat for storms will be across the Piedmont, mainly along and south of the surface boundary, where surface-based CAPE will be maximized. Bulk shear still appears weak, and PWATs are expected to range from 1.4 to 1.8 inches. Do not expect the entire day to be a wash-out by any means, and Sat could start dry for most, but there will be a chance for showers across all of central NC, with greatest coverage from Sat eve through Sun aft. Highest chances NW, lowest SE. Given the high PWATs and scattered, somewhat disorganized mode of convection, isolated locations could receive locally heavy rainfall, with any potential for minor flooding issues largely limited to urban areas. Temperatures: A bit tricky on Sat, as there is some bust potential north of the front. Widespread overcast skies should somewhat limit heating as well. For now expect highs to range from the mid 70s along the NC/VA border to mid 80s SE. Sat night temps should be continued mild, mainly in the low to mid 60s. On Sun, with the retreat of the front northward, areas across the north may be a few degrees higher than Sat, but given the expected showers/storms through the day, temps may otherwise be limited. Highs in the upper 70s north to low 80s south. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 329 PM Friday... The extended forecast upper pattern will largely include mid-level ridging over the eastern US. A stronger short-wave will move over the area Monday into Tuesday increasing rain chances. After relatively zonal flow Tuesday, mid-level ridging will then re- amplify over central NC through the end of the extended. Another potentially stronger trough may approach late in the period. Monday/Tuesday: A potent mid-level short-wave and associated vorticity max is forecast to move across the southern Appalachians Monday afternoon. Mid-level height falls will maximize over us later Monday afternoon/early evening coinciding with peak heating/instability. At the sfc, a piedmont trough will develop Monday afternoon which, in combination with forcing aloft, should help to focus showers and storms across our area. Bulk layer shear will be much too weak to support severe storms, but given the presence of anomalous PWAT (150 to 200 % of normal) any storm that develops could produce brief heavy downpours and gusty winds. POPs should decrease late Monday night/early Tuesday morning as flow aloft turns a bit more nwly and the atmosphere stabilizes. In absence of upper forcing aloft, rain chances Tuesday afternoon will largely rely on diurnal shower/storm development which should remain mostly scattered. Temperatures Monday will peak in the mid to upper 80s, increasing into the upper 80s by Tuesday afternoon. Wednesday/Thursday: The mid-level ridge will re-establish itself Wednesday and Thursday as temperatures soar into the lower to mid 90s. The NBM is particularly stoked about 90 temps for highs these days with >80% of it`s members reaching this threshold for much of this area. The LREF (GEFS, GEPS, EPS) is a little less enthused on Wednesday, but does suggest decently high probabilities on Thursday (generally 40 to 60 % across the area). Otherwise, anomalous moisture will remain in place Wednesday/Thursday which should promote a continuation of low-chance POPs each afternoon. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 800 PM Friday... Generally VFR conditions will continue through 06z tonight. IFR to LIFR CIGS and MVFR vsbys are expected to develop over a swath of central NC later tonight 08z-09z and linger into Saturday 15z-16z. In addition scattered showers will become more numerous Saturday, with isolated thunderstorms. The showers will linger into Saturday night with lingering IFR to LIFR conditions. Outlook: IFR-MVFR ceilings are likely to redevelop each night- morning through Monday, as are scattered to locally numerous showers/storms each afternoon-evening. && .CLIMATE... Record High Minimum Temperatures: May 4: KGSO: 65/2022 KRDU: 68/1938 KFAY: 68/1942 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Green NEAR TERM...Green SHORT TERM...KC LONG TERM...Luchetti AVIATION...pwb/MWS