Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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622 FXUS62 KRAH 301852 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 250 PM EDT SAT JUL 30 2016 .SYNOPSIS... Hot temperatures and scattered afternoon and evening showers and thunderstorms will persist through the rest of the weekend and into early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 250 PM Saturday... Scattered showers and tstms have developed as expected across central NC, invof of the Piedmont trough, and to our west over and just east of the mountains. Aloft, sw flow persists across our area on the east side of a broad trough centered over the Ohio and Mississippi valleys. For the rest of this afternoon into this evening, the aforementioned showers and tstms will move east across our cwa, but given the scattered nature, not all locations will see rain, so for now will keep pops capped at 50%, implying the scattered coverage. As for tstm intensity, latest mesoanalysis shows plenty of instability, esp from the US-1 corridor eastward, but shear is pretty weak, so look for mostly pulse storms, with perhaps some modest clustering north and northeast of Raleigh where the effective shear is the highest in our cwa. Given the instability, an isolated severe cell (wind or hail the main threats) can`t be ruled out, but given the weak shear, any severe cells won`t remain severe very long. Again, the best chance for a strong or severe cells will be north and northeast of Raleigh closer to the better shear. Look for shower/tstm activity to wind down around midnight, with the remainder of the night partly cloudy. With little or no pattern or airmass change, will lean toward persistence for temps. Low`s tonight in the mid 70s. && .SHORT TERM /Sunday through Sunday night/... As of 250 PM Saturday... Sunday will start off much like today, with pc skies and isolated showers or sprinkles perhaps lingering on old outflow boundaries. Like today, isolated-to-scattered showers and tstms are expected to develop invof of the Piedmont trough during the early-to-mid afternoon. Then during the early evening, guidance is suggesting that a broken band of thunderstorms, first having formed over the mountains, will move east across our cwa. This band of tstms may have a little better coverage since it will be supported by a shortwave embedded in the sw flow. That shortwave is currently moving across the central plains. Despite this upper support, 0-6km shear is still progged to be aob 25 kt. So once again, most storms should remain below severe limits, but an isolated severe cell or two still can`t be ruled out given the instability. Speaking of instability, temps and dew points on Sunday will be similar to today, given that the airmass will have changed little. However, with slightly increased shower/tstm coverage, our confidence of hitting heat advisory criteria in our eastern counties is not particularly high. For now, will forecast highs in the lower 90s and heat indices around 100. Nevertheless, it will still be uncomfortably hot, so folks need to continue exercising the heat precautions that we`ve been advertising. && .LONG TERM /Monday through Saturday/... As of 245 PM Saturday... Relatively flat upper level trough will extend from New England into the Carolinas at the beginning of the week. Perturbations rounding the base of this trough will interact with available moisture (precip water values hovering around 2 inches Mon and Tues) and instability to trigger scattered convection. The bulk of the convection will occur during the afternoon-early evening hours and concentrated along a sw-ne orientated surface trough bisecting our region. An upper level ridge centered over the lower MS Valley/southern plains is projected to amplify northward in response to an upper level low crossing the Pacific NW. This should lead to building heights over central NC the later half of the work week, leading to a decreasing chance for afternoon/evening convection. High temperatures early in the week will average close to normal due to anticipated cloud and convection coverage. High temperatures will likely return to above normal levels later in the week as the upper level ridge exerts its influence on our weather. && .AVIATION /18Z Saturday through Thursday/... As of 250 PM Saturday... 24-Hour TAF period: Through 31/04z, scattered showers and thunderstorms will locally reduce cigs and vsbys to mvfr or ifr category. Outside of thunderstorms, look for VFR conditions and winds generally from the w-sw 10-15kt. Higher/variable gusts near tstms. After 31/04z until 31/12z, look for mostly VFR conditions with light s-sw wind. From 12z Sunday and beyond: similar conditions Sunday-Tuesday with scattered afternoon/evening tstms and associated reduced flight conditions. Patchy morning fog possible as well. During the mid-week period, we may see decreased daily shower/tstm chances as slightly drier air moves in the from the north. && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM EDT this evening for NCZ028-043-078-085-086- 088-089. && $$ NEAR SHORT LONG TERM...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.