Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 220017 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 817 PM EDT Mon May 21 2018 .SYNOPSIS...
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A moist and unstable air mass will remain entrenched across central NC through the middle of the week. A cold front will move through the area on Wednesday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 315 PM Monday... Latest sfc analysis shows a weak backdoor front stretching across the northern portion of the state, just south of the VA border. Radar shows scattered showers and tstms developing invof of this boundary. The latest HRRR shows this area of shower/tstm activity expanding as the afternoon progresses. While not every area will see rain, the best chance for rain will be north of the line from Albemarle to Clinton, this afternoon through the evening. The latest mesoanalysis shows that the best instability is located north and east of Raleigh. While there is also an area of elevated DCAPE north and east of Raleigh, deep layer shear is rather modest. This suggests that the main concern will be wet downbursts for any cells with elevated cores. Also modest mid-level winds in this mornings soundings suggest that slow-moving storms could produce locally higher rainfall amounts. Look for the storms and subsequent rain this evening to gradually diminish as the night goes on. Despite mostly cloudy conditions tonight, given the light winds and high dwpts, there could be a few patches of fog late tonight, esp areas that see the rain this evening. Low in the upper 60s to near 70. && .SHORT TERM /Tuesday through Tuesday night/... As of 315 PM Monday... The boundary that`s currently over our area is expected to lift back to the north by 12Z Tuesday. However, there is some indication in models that a weak mid-level short wave moving up from the south could prolong the risk for showers across our north/northeast zones between daybreak and noon Tuesday. However, once this feature passes, a pocket of dryer air in its wake should give us a brief break in rain chances during the afternoon, esp across across the eastern half of our CWA. By Tuesday evening and night, we`ll turn our attention to a cold front approaching from the northwest (the system currently across the northern/central Plains). Models suggest that pre-frontal shower and thunderstorm activity will begin approaching our western zones as early as Tuesday evening, with best chances for rain across our western and central zones overnight into Wednesday morning. With little change in the airmass, expect highs Tuesday again in the low-mid 80s and lows Tuesday night in the upper 60s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 235 PM Monday... The subtropical ridge off the Southeast coast will keep central North Carolina in a tropical airmass on Wednesday. A frontal zone dropping southward from the Mid Atlantic will enter northern parts of the region Wednesday night and become stationary close to the NC/SC border on Thursday. The tropical airmass will be suppressed to the south of the boundary Thursday and Friday before returning northward into central North Carolina over the holiday weekend. In addition, a tropical low is forecast to move northward across Cuba and the Gulf of Mexico/Florida over the holiday weekend and early next week. Diurnal heating combined with the frontal boundary will generate scattered convection Wednesday afternoon and evening. Scattered convection Thursday and Friday should be limited to locations near the NC/SC border and western Piedmont. Convection will overspread the entire region over the 3-day holiday weekend with the return of a tropical airmass and close proximity of the tropical low. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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As of 817 PM Monday... Ongoing cluster of thunderstorms across the central Piedmont will impact KRDU through 02 to 03z, resulting in IFR to MVFR ceilings and visibility restrictions. Elsewhere, convection has weakened significantly across the area. As such, do not expect any significant aviation impacts from storms at KINT, KGSO, KRWI, and KFAY. Areas of fog/stratus will be apt to form between 06 to 12z, especially in/near areas that receive heavy rain. Any sub-VFR cigs Tuesday morning will quickly lift to VFR with heating. Convective rain chances Tuesday afternoon are expected to be significantly lower than today, generally isolated to widely scattered. Outlook: A cold front will push SSE through the area late Wednesday and Wednesday night. Numerous showers and thunderstorms are expected to accompany the cold front. With the cold front forecast to stall south of the area Thursday and Friday, expect drier conditions through the remainder of the work week. However, rain chances will be on the increase on Saturday as moisture overspreads the area from the south.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ NEAR SHORT LONG TERM...Franklin AVIATION...CBL is the U.S. government's official web portal to all federal, state and local government web resources and services.