Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250527 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1230 AM EST Sun Feb 25 2018 .SYNOPSIS... High pressure centered off the Southeast coast will gradually drift southeastward tonight and Sunday. A cold front will move slowly east across the area Sunday night and into Monday. Cooler high pressure will build in from the north Monday night and Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 1015 PM Saturday... Deep mid/upper level ridging located off the Southeast U.S. coast will continue to slowly be pushed further southward overnight as s/w energy lifts from the Plains into the Upper Midwest and Great Lakes region allowing for a cold front to approach the area from the west. This has allowed for some increase in mid/high clouds across the area (especially the northern half). This combined with a nice southerly flow overnight should overall limit fog potential. However, we could see at least some patchy fog across the far south/southeast along with the potential for stratus development areawide. With regard to precip chances, while we cant completely rule out some sprinkles across the far Northwest Piedmont early Sunday morning, expect generally dry conditions. Overnight lows should be quite mild again, near record high mins. Expect lows will generally be in the lower 60s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 355 PM Saturday... The remnants of today`s mid/lower Miss Valley convection will track well to our north through Sun morning, but this will help tamp down the SE Coast/Mid Atlantic mid level ridge. Upshear, a subtle trailing perturbation tracking NE over N Mexico late today is expected to track NE over the S and central Appalachians on Sunday, along and ahead of the incoming surface cold front. Decent low level moisture transport into our area will persist Sun, however much of central NC, particularly S and E of the Triad, will see lingering relatively dry low and mid level air, with rather timid surface dewpoint advection compounded by good mixing to limit potential instability. Kinematics and dynamic forcing will be small through the first part of the day, but mid level winds will accelerate late in the day Sun and into Sun night, and a southerly 850 mb jetlet around the periphery of the offshore ridge, just off the E coast of Mexico and TX this evening, is projected to sweep E/NE and into the Carolinas, leading to increasing low level mass convergence along and ahead of the front Sun night. Expect increasing pops to good chance Sun afternoon, with isolated thunder possible in the SE CWA based on projections of a few hundred J/kg of MUCAPE and strengthening deep layer shear, although mid level lapse rates are quite poor, which should greatly hold down the thunder risk. Will trend pops up to likely and categorical from the SW Sun night, with the highest pops in our SW. With the delay in precip chances, highs should range from the lower 70s NW to lower 80s SE. Lows from the mid 50s to the lower 60s, with the front settling into the Piedmont overnight. -GIH && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 245 PM Saturday... Models maintain their consensus on a wave lifting northeast along the stalled cold front on Monday, and will be raising PoPs to categorical across the southern tier. In addition, will add a chance for rumblers in the southeast where even though instability will be very weak to non-existent, we will have just about everything else needed - low level convergence, shear, and upper dynamics - to support at least modest convection. Cool air will be flowing in behind the wave, and highs will struggle to make much headway in the cloudy and moist airmass, so expect the northern tier to stall in the upper 50s, while the southeast should reach mid 60s. Cooler airmass settles in Monday night, with lows bottoming out mostly in the lower 40s, with some upper 30s possible across the north where radiational conditions (decoupling) will be more favorable. Dry high pressure will build across the area, and quickly offshore Tuesday into Tuesday night, with sunny skies and highs climbing to 60 to 65 on Tuesday with mins in the mid 40s Tuesday night. Moisture will increase rapidly in return flow on Wednesday, with showers increasing in the west and spreading into central NC during the afternoon. There is a bit of uncertainty as to how shortwaves in the northern and southern streams, respectively, will phase during the mid to late week period. Regardless, it looks pretty wet as a warm front lifts north up the Atlantic coast ahead of what will be a strong low pressure area and associated cold front moving east across the Ohio Valley/Great Lakes region. The surface cold front will move across the area later Thursday, so will have likely PoPs Wednesday night through Thursday as timing confidence is not high this far out. Highs Wednesday will reach the low to mid 60s, while we should be mild Wednesday night ahead of the front...50 to 55. Strong warm air advection ahead of the front will allow us to reach 65 to 70 on Thursday. The low pressure system is expected to slow and make a southeasterly jog as it moves offshore, which could change the equation, but at this point, lingering showers should be gone by Friday morning, with seasonable highs Friday and cooler air settling south on Saturday. Highs Friday will be mostly in the lower 60s, with Saturday topping out from 55 to 60. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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As of 1230 AM Sunday... VFR conditions continue to hold across all TAF sites at this hour. Some MVFR to brief IFR drops will be possible close to daybreak, mainly thanks to a pesky low level stratus deck that may form, especially across the south and east. Otherwise, the forecast area should remain well mixed, with wind 8 to 12kt sustained surface winds with gusts up to 20kts possible overnight. Any sub-VFR cigs will start to lift and break up by late Sunday morning with precipitation chances increasing from west to east during the afternoon. Some variability in aviation categories may persist as showers push through, but confidence on timing and impact remains low this far out. A trend to sub-VFR conditions will begin Sunday night as a cold front moves slowly SE through the area, settling across SE NC Mon morning. Sub-VFR conditions with showers and isolated storms will be the most likely and the longest lasting over the SE (FAY), lasting through much of Mon, while at other sites, high pressure will start to build in behind the front, leading to a trend to mostly VFR conditions Mon at INT/GSO/RDU/RWI. VFR conditions will dominate Tue/Wed under high pressure. The next chance for sub-VFR conditions will be Wed evening/night into Thu as the front heads back northward into the area as a warm front, bringing a chance for showers.
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&& .CLIMATE... RDU Records: Date | High Year | High Min Year ------------------------------------------ 02/25 82 1930 58 1985 GSO Records: Date | High Year | High Min Year ------------------------------------------ 02/25 81 1930 55 1985 FAY Records: Date | High Year | High Min Year ------------------------------------------- 02/25 85 1930 57 1992 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield/Franklin NEAR TERM...BSD SHORT TERM...Hartfield LONG TERM...mlm AVIATION...JJM/Hartfield CLIMATE...RAH is the U.S. government's official web portal to all federal, state and local government web resources and services.