Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 220034 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 830 PM EDT Wed Jun 21 2017 .SYNOPSIS... A moist southwesterly return flow will prevail over the Carolinas through the end of the work week. && .NEAR TERM /TODAY AND TONIGHT/... As of 605 PM EDT Wednesday... Near term forecast was recently updated to adjust the PoP to chance across sections of southern counties of central NC. This region primarily south of highway 64 in a zone of modest moisture convergence, associated with a boundary at 850mb. This boundary along with heating from late afternoon sun has aided to trigger isolated/scattered showers along this feature. While the bulk of the showers will dissipate with loss of heating, the tropical air mass over the region will support isolated showers past midnight. Otherwise, expect variably cloudy skies tonight with overnight temperatures in the upper 60s to around 70. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... As of 1250 PM EDT Wednesday... Widespread convection is expected over the Deep South tonight/Thu as Tropical Cyclone Cindy makes landfall in vicinity of the TX/LA border. Latent heat release assoc/w the aforementioned convection is expected to amplify a ridge downstream over the central Appalachians and portions of NC/VA late tonight. Subsidence attendant the aforementioned ridge should suppress precipitation and result in dry conditions through ~noon. However, strengthening low-level warm advection (from the SW) and MCVs (emanating from upstream convection) lifting NNE into the southern Appalachians will weaken ridging aloft over the region and allow convection to expand NE from upstate SC/southwest NC into portions of central NC Thursday afternoon, primarily the W/SW Piedmont. Expect highs ranging from the lower/mid 80s in the far W/SW Piedmont to lower 90s in the E/NE Coastal Plain. Convection should assume a WSW-ENE orientation and lift north toward the NC/VA border Thu night as Cindy`s remnants progress into Arkansas and southerly flow aloft upstream over the Deep South veers to the SW. Expect the relative best chance for precipitation in the N/NW Piedmont. Chances for precipitation will decrease to the south and east such that dry conditions are likely in the SE Coastal Plain. Expect lows in the lower 70s. -Vincent && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... As of 345 PM EDT Wednesday... Model consensus, which is closely in line with the official NHC, tracks the remnants the of T.S. Cindy through the TN Valley on Friday and then through the Southern Mid-Atlantic states on Saturday as it gets picked up by the belt of westerlies attendant to the northern stream trough. The resurgence of deep moisture that`s slated to lift back over the area on Thursday-Thursday night, temporarily wanes on Friday as the brunt of upper disturbances(likely to be convectively induced) lift off to the north. So it`s possible that after the morning rain showers, most of the area, particularly south of I-85 could end up mostly dry on Friday, with only slight/small chance of showers/storms possible Friday afternoon, owing to strong daytime heating within the moist low-level airmass. Models are starting to come into better agreement with the timing and magnitude of Cindy`s remnants, trending towards a more progressive/sheared solution, which now brings the system through the area between 06 to 15z Saturday. Thus, the threat for heavy rain and flooding appears to be decreasing across central NC, with the latest GFS and EC now showing less than an inch across the area. Additionally, given earlier-less favorable diurnal timing, severe threat appears very low as well. Confidence remains lows with the timing and amplitude of embedded shortwave troughs within the Eastern US trough, with the potential for a series of sfc cold fronts to move through the area Sunday and again on Monday. Appears the better convective rain chances will be in the east, in closer proximity to axis of deeper moisture, otherwise, considerably drier air across the western part of the state should limit pops. Will indicate slight to small chance pops both Sunday and Monday. Highs Friday through Monday should range in the mid/upper 80s NW to lower 90s SE, with balmy lows in the 70s. Below normal temps and less humid conditions will follow in the wake of the secondary cold front Tuesday and Wednesday. && .AVIATION /00Z Thursday through Monday/...
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As of 830 PM Wednesday... VFR conditions will persist until at least 06z, as a ridge of high pressure extends across the area. After 06z, nighttime cooling combined with increased low level moisture will lead to development of patchy IFR stratus overnight. 07z-12z will be the most likely time of occurrence of sub-VFR cigs, and any sub-VFR cigs should lift to VFR by around 13z. High clouds will thicken and lower to 7,000- 10,000 ft AGL after 17z as a disturbance aloft approaches from the south. Light rain is expected to form over SC and southern NC by midday or early afternoon Thu and spread northward through the afternoon, although cigs and vsbys are likely to remain VFR as cloud bases should be mostly above 6,000 ft AGL. Winds will be from the SW around 5-9 kts tonight and 8-13 kts after daybreak Thu. Looking beyond 00z Fri (Thu evening), the light rain is expected to diminish in coverage during the evening as the disturbance shifts to our north. IFR/LIFR cigs are expected to develop after 06z Fri, with the highest confidence near INT/GSO. These cigs will be slower to improve after daybreak Fri morning, rising slowly to MVFR after 13z and then to VFR after 16z. VFR conditions will dominate Fri afternoon into Fri night, although areas of rain will likely spread into the area late Fri night into Sat as the remnants of Tropical Storm Cindy shift by to our west and north. INT/GSO will see the best chance for sub-VFR conditions with this rainfall. A front will push southeastward through the area late Sat or Sat night, and VFR conditions should rule over much of the area Sat night through Mon, although sub-VFR conditions in rain may linger at FAY. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Vincent NEAR TERM...WSS SHORT TERM...Vincent LONG TERM...CBL AVIATION...Hartfield

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