Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 010813 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 313 AM EST Thu Dec 01 2016 .SYNOPSIS... A cold front will cross the area early this morning. High pressure will then build over the Eastern U.S. from the west through the upcoming weekend. An approaching upper level disturbance and increasing moist flow from the Atlantic and Gulf will bring increasing rain chances beginning Sunday night. && .NEAR TERM /today through tonight/... As of 225 AM Thursday... The cold front has just cleared the northwest CWA, where clouds have cleared out, winds have taken on a primarily westerly component, and dewpoints have fallen into the 40s. Such changes will progress steadily eastward for the balance of the night, with the remaining light showers over the eastern Carolinas including our far SE sections (oriented along the departing 850 mb jet) ending in the next few hours. The continental surface high that will build in behind the front from the WSW today is sufficiently modified such that this initial post-front drop in temps won`t be extreme, with slightly above normal thicknesses supporting seasonably mild highs of 59-68 under plentiful sunshine and lighter (yet still periodically gusty) winds. The generally clear skies will continue through tonight; however, a weak shortwave trough located over the Front Range early this morning is projected to track quickly across VA tonight, potentially bringing a few high thin clouds as mid level winds remain rather brisk. Overall, though, expect fair skies at most overnight, with a slackening MSLP gradient yielding light winds. Expect lows of 32-39. -GIH && .SHORT TERM /Friday through Friday night/... As of 240 AM Thursday... Forecast soundings show deep dry and stable air across Central NC on Friday, with a fairly flat and fast mid level flow and high pressure still building in at the surface, leading to generally sunny skies. As this southern stream surface high begins to merge with the larger Canadian high to its NNW, low level thicknesses will drop further on Friday, to around 10-15 m below normal, so temps should follow suit with below normal highs of 53-60. High clouds are expected to being increasing Friday night, spreading in ahead of convection over TX and the lower Miss Valley (ahead of the digging low over NW Mexico). These initial high clouds should be thin however as they encounter the destructive effects of broad ridging over the Gulf States and Southeast, and thus they should do little to impede radiational cooling. Lows 30-35. -GIH && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 312 AM Thursday... The long term will start out dry and cool as high pressure moves across the Ohio Valley and into the mid-Atlantic states on Saturday and Saturday night. Expect high temperatures to top out in the low 50s on Saturday with lows in the mid 30s. Sunday will be a more active and colder day as the high initially sets up over the eastern half of the state and some lower thickness values sink down from the north causing highs to be right around 50 degrees with an overcast low to mid level cloud deck. Later in the day a somewhat disorganized inverted trough pushes northward out of the deep south and isentropic lift begins to increase Sunday night as a low tries to develop just offshore. This will lead to precipitation chances increasing on Sunday with the bulk of the precipitation with this wave occurring Sunday night and Monday morning. Expect anywhere form a couple of tenths of rain across the north to closer to a half inch in the south. Monday could see a lull in the precipitation between the exiting wave and a much larger system approaching from the southwest which I will talk more in depth about in a minute but for Monday a weak high passing to the north could help to get that pause in precipitation, especially across the north. Temperatures will be a little warmer as thicknesses increase. Highs in the low to mid 50s. Lows Monday night in the upper 30s to near 40 degrees. Precipitation chances will pick up significantly on Tuesday as models are in agreement on a Miller B scenario with two low pressure systems coming at us from the southwest, one will eventually move up the Carolina coast with the second through the Tennessee Valley. Diverging upper level flow will move the two lows further apart as they pass over us but that divergence aloft will also provide some good lift that will most likely make Tuesday a wash with early precipitation estimates between an inch and an inch and a half of rain possible from early Tuesday morning through early Wednesday. Highs Tuesday in the mid 50s with lows in the low to mid 40s. Wednesday should see the return of mostly dry weather as the system lingers offshore. Warmer with highs in the mid to upper 50s across the NW piedmont and lower 60s in the southeast. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... As of 105 AM Thursday... Widespread MVFR cigs have given way to VFR at INT/GSO as the cold front approached from the west. Similar improvement is expected at RDU/RWI/FAY between 08z and 11z, with VFR conditions areawide by 12z, as the cold front sweeps through the area and high pressure begins to build in from the west. Current surface winds from the SW at 10-15 kts gusting occasionally to 20-25 kts will veer to westerly then northwesterly later this morning with diminishing speeds to around 10 kts and infrequent gusts to 15 kts, lasting into the afternoon as VFR conditions persist. Winds will diminish further after 22z late today, with VFR conditions holding through tonight. Looking beyond 06z early Fri morning, VFR conditions will hold well into the weekend as the ridge of high pressure builds into the area. High clouds will spread in from the WSW on Sunday, and these clouds will thicken with lowering bases to MVFR then IFR Sunday night as an upper level disturbance approaches from the WSW, in conjunction with increasing low level moisture from the Atlantic and Gulf. MVFR to IFR cigs/vsbys will persist through Monday with light rain developing. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...Ellis AVIATION...Hartfield

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