####018007472#### FXUS62 KRAH 040620 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 220 AM EDT Sat May 4 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 /06Z SATURDAY THROUGH WEDNESDAY/... As of 220 AM Saturday... A back-door cold front, noted by a E-NELY wind shift, will settle south across the northern TAF sites over the next few hours before stalling. Moisture pooling along the front should lead to the development of IFR to MVFR ceilings at all TAF sites 08 to 12z. Ceilings at KFAY, KRDU, and KRWI should gradually lift to VFR from south to north through 17-18z, with scattered showers and storms possible during the afternoon and evening, especially at KRDU. At KGSO and KINT, ceilings could remain IFR to MVFR through the afternoon and evening as intermittent showers and storms develop and move through the area through much of the forecast period. Showers will linger across the area tonight, with the re-development of LIFR to MVFR conditions across the area, lowest at KINt and KGSO where the deepest moisture resides. -CBL Outlook: IFR-MVFR ceilings are likely to redevelop each night- morning through Monday, as are scattered to locally numerous showers/storms each afternoon-evening. -MWS && .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...CBL/MWS ####018005473#### FXUS62 KILM 040621 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 221 AM EDT Sat May 4 2024 .SYNOPSIS... Scattered showers and thunderstorms will develop this weekend as due to several upper level disturbances and localized low pressure. High pressure will build overhead by Tuesday with well above normal temperatures likely during the middle and late portions of next week. Rain chances increase towards the end of next week due to an approaching frontal system. && .UPDATE... No changes to the forecast with the mid evening update. Next several hours the forecast is fog oriented and with inherited good coverage...it's probably a fool's gold to fine tune but will take a second look later. && .NEAR TERM /THROUGH TONIGHT/... Persistent low level south-southeasterly flow will lead to another night of saturation near ground level. Best chance for fog, potentially dense, will be across the Cape Fear region and possibly parts of coastal northeast SC. Confidence in fog development decreases further inland as edge of mid/high level cloud deck will be across western parts of the CWA. May be more low stratus inland vs the expected fog closer to the coast. Regardless, any fog/stratus will clear after sunrise. Temps will be only slightly lower on Saturday, with highs in the low 80s. Main forecast problem in the near term is rain chances beginning midday Saturday and continuing through the day. There is going to be a rather sharp moisture gradient in the vicinity of I-95 during the day Saturday, with 1.6" PWAT to the west and near an inch at the coast. This is mainly due to rather dry mid levels around offshore ridge, with 20% RH at 700mb at the coast tomorrow afternoon. Current thinking is scattered storms (40-50% chance) possible across western parts of the CWA beginning midday, with upper level impulses moving across from the SW around ridge offshore and trough to the NNW. How far inland that intrusion of mid level dry air gets will determine edge of best rain chances. && .SHORT TERM /SUNDAY THROUGH MONDAY/... Pulses of shortwave energy overhead paired with localized lower pressure leads to shower/storm chances through the short term period. Sat night the coast could remain dry before moisture starts to recover late. The axis of better moisture will push into the area along with the shortwave Sun with continued chances for convection, particularly during the afternoon and along the sea breeze. The shortwave will move offshore Sun night with activity expected to wind down overnight. Another shortwave approaches Mon with greater precip chances with the addition of instability. Highs in the low to mid 80s with lows in the mid 60s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Rain chances continue through Tues where one last push of energy moves through aloft before ridging builds in for midweek with quiet weather. Under this ridge, highs will increase into the 90s with humid conditions. No heat advisory concerns with the current forecast. High temp records for Wilmington NC and Florence SC are a couple degrees above what is in the forecast for Wed and Thurs, so this heat will be something to keep an eye on. Rain chances return late Thurs through the end of the period with an approaching frontal system. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Looking at VFR/MVFR conditions thru 08Z, then dropping to IFR/LIFR at the coastal terminals with mid and upper level clouds possibly limiting the inland terminals to just IFR at its worst. Between 08z and 12z, BR/FG lowering vsbys and sub 500 ft OVC or VVs will dominate. After 13z, SSE-S 5 to 10 kt winds pick up and the days heating commences, which should dissipate any leftover flight restrictions rather quickly. Some guidance indicates possible convection across the inland terminals this aftn and will indicate with VCTS, this followed by prob30 for shra thru this evening for the same inland terminals. Extended Outlook...Scattered convection will bring periodic visibility and ceiling restrictions Sun into Mon. Otherwise, looking at VFR dominating outside the pcpn and becoming the mainstay Tue into Wed. && .MARINE... Through Saturday...Benign marine conditions continue through Saturday courtesy of offshore high pressure. Seas linger in the 1-2 ft range tonight and tomorrow, combination of 1-2 ft SE wind wave and 1 ft E swell. South-southeast winds persist, predominantly less than 10 kts outside of localized sea breeze enhancement Saturday afternoon. May see some patchy fog close to the Cape Fear coastline early Saturday morning, but confidence is low on how low visibilities may get and how far offshore any fog may impact. Saturday Night through Wednesday...Flow around the Bermuda high will lead to SE to SW flow through the period. Sub-SCA conditions with wind speeds 10-15 kts and seas 2-3 ft increasing to 3-4 ft Wed with an increasing southerly wind wave and some long period swells from the E/NE. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...SHK NEAR TERM...VAO SHORT TERM...LEW LONG TERM...LEW AVIATION...DCH MARINE...VAO/LEW