Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280650 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 250 AM EDT Sat May 28 2016 .SYNOPSIS...A tropical depression off the Southeast coast will drift slowly northwest toward the South Carolina coast through Sunday, before turning northeast and tracking off the southeast North Carolina coast through Wednesday. && .NEAR TERM /through tonight/... As of 250 AM Saturday... What is currently TD2 (projected to become TS Bonnie) is located off the SE coast east of JAX early this morning, and it will continue tracking NW toward the Southeast coast today and tonight, following a path along the weak NW-to-SE-oriented mid level shear axis now extending across SC and SW NC. Bermuda high pressure continues to nose westward across NC, providing subsidence and mostly clear skies through this morning, although this will give way to the slowly incoming cloud shield associated with TD2 later today. While the TD is not expected to move close to shore until late Sun, the strengthening low-fetch low level southeasterly inflow on the TD`s north side will draw plentiful moisture into central NC starting late this afternoon, with PW values aoa 1.5" supplanting the sub- 0.75" PW now in place over the area by this evening. The latest model runs are slower in bringing substantial precip into central NC, depicting little to no coverage outside of the far SE counties until late today. Based on the stubborn nature of the Bermuda surface ridge along with the mid level dry air noted on forecast soundings, the current cloud trends, and the passage of the bulk of the initial DPVA to our south within the mid level shear axis, have delayed precip onset, will focus pops on the SE only for much of the day. Upper divergence ramps up after nightfall along with moist upglide, and PW values are projected to approach 2.0 inches (mainly east half) tonight. Will retain a steady upward trend of pops from SE to NW, reaching likely pops areawide by late tonight with an abundance of deep moisture and improving dynamic forcing for ascent. Expect highs today of 82-87, "coolest" over the SE given the earlier clouds and precip arrival. Warm lows tonight of 63-69. -GIH && .SHORT TERM / /... As of 325 PM Friday... To be updated shortly. && .LONG TERM /Sunday Through Friday/... As of 305 PM Friday... Sunday through Tuesday: The likely tropical/sub-tropical low is expected to be located very near the South Carolina coast Sunday morning, shown by nearly all of model guidance. However, where the sub-tropical/tropical/remnant low tracks after approaching/moving onshore is still in question. Given the approaching system and influx of tropical moisture into central NC, we should see numerous to widespread showers and thunderstorms on Sunday as the inverted surface trough pivots westward and into our area. This will lead to the potential of heavy rain with any showers and storms as PW`s are expected to surge to around/over 2 inches, along with at least some threat of at least isolated severe storms. With regard to the severe threat, there is still some uncertainty about how much instability we will have and how strong the deep and low level shear will be, with the eventual track and intensity of the system playing a major role. High temps Sunday should be limited to around 80 degrees thanks to the convection and mostly cloudy/overcast skies, but with quite humid conditions. The latest GFS and NAM shows the system lifting northward across the coastal plain of the Carolinas on Monday night into Tuesday and being absorbed in a passing northern stream s/w. The latest ECMWF is hinting at this potential now as well, which differ some from its previous run and has more of a drier solution across most of central NC by Monday, with any heavy rain/rain generally from the I-95 corridor and eastward. However, will maintain continuity for now with previous forecasts and still show at least likely pops across the eastern half of the area. Chances for showers and storms are expected to decrease further Monday night into Tuesday with any lingering trough axis located along the coast (higher chances east vs west for central NC). High temps on Monday and Tuesday are expected to be in the lower to mid 80s, with lows in the mid to upper 60s. Tuesday night through Friday: Will trend chances for showers and storms more towards climo with poor run to run model continuity, along with model differences. This will yield generally diurnal chance pops with high temps in the lower to mid 80s and lows in the 60s. && .AVIATION /06Z Saturday through Wednesday/... As of 123 AM Saturday... VFR conditions are likely at all sites through today, although MVFR conditions will begin to move into FAY then RDU/RWI starting after 21Z. Additionally, RWI is likely to see banks of dense fog this morning which could briefly restrict vsbys there to under 2 miles. High pressure centered well offshore continues to nose westward across NC early this morning, yielding generally light winds and mostly clear skies. A tropical depression located off the Southeast coast is expected to continue tracking to the NW toward the SC coast today, and the resulting increase in low level flow from the SE into NC will gradually pull Atlantic moisture into our area, causing clouds to thicken with lowering bases from SE to NW. FAY is expected to trend to MVFR cig/vsby after 23Z, RWI after 00Z, and RDU after 02Z as patchy light rain spreads in from the SE. Surface winds will be initially from the south then shift to be from the SE this morning, holding under 10 kts through tonight. Looking beyond 06z early Sun morning, cigs/vsbys are likely to become MVFR at all central NC sites by Sun morning with areas of rain, as the tropical system approaches the SC coast near CHS by Sun evening. MVFR conditions will remain common through Sun with on-and- off showers, although a period of IFR or VFR conditions may occur. The tropical system is then expected to weak as it tracks northeastward off the northern SC and SE NC coast through Mon, and after areas of fog and perhaps IFR stratus Sun night, VFR conditions should return Mon afternoon. A humid pattern will hold Tue/Wed with IFR fog possible each morning, but otherwise VFR conditions will dominate Tue/Wed. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM... LONG TERM...BSD AVIATION...Hartfield is the U.S. government's official web portal to all federal, state and local government web resources and services.