Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 221837 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 237 PM EDT Sun MAY 22 2016 .SYNOPSIS...A strong upper-level low pressure area will settle over the area today through Monday, producing unsettled weather. Warmer and drier weather will follow from Tuesday through late week as the upper low moves offshore and high pressure builds across the area. && .NEAR TERM /through tonight/... As of 1045 AM Sunday... Little change required to the near term forecast. 12z upper air analysis depicts strong cyclonic flow over central NC with an upper level low positioned over the northern Mid-Atlantic states. Around this low are a series of vort axes, one which is crossing our region late this morning, triggering a band of scattered rain showers across the northern piedmont. This mid level feature will continue to drift to the east-southeast, triggering additional shower development in the coastal plain and eastern piedmont this afternoon. While the western piedmont will see little if any showers through mid afternoon, shower activity expected to increase late this afternoon, and more so this evening, as another vort axis approaches from the north. While instability is marginal and conditional, went ahead and added the mention of an isolated thunderstorm for this afternoon. The highest threat for thunder will be along and east of highway 1. Cloud cover expected to remain abundant this afternoon. This, along with scattered showers in the east, will hold temperatures down several degrees from normal high temps for late May. Max temps this afternoon should vary from around 70 north to the low-mid 70s south. Tonight, the approach and passage of the next vort axis will maintain a few showers across the region. The upper level low will drift south and settle overhead by early Monday. The pool of cooler air aloft will transfer to the south, resulting in overnight temps about 5 degrees cooler than last night. Min temps by early Monday should range from around 50 across the far north-northwest to the low-mid 50s south. && .SHORT TERM /Monday and Monday Night/... As of 310 AM Sunday... The mid/upr closed low will continue to be the main player in our weather as it slowly moves from NE NC in the morning eastward and offshore by evening. Despite the mid-level cooling on the back side of the low, forecast soundings indicate only modest instability. Nevertheless, there should be enough mid/upr energy assoc with vort maxes rotating around the low to provide adequate support for scattered afternoon and early evening showers. Worth noting that these showers should be fairly brief with limited rainfall. Thanks to the ongoing northerly flow, below normal temps will continue. Highs from around 70 north to mid 70s s/sw. Lows monday night in the lower-mid 50s. && .LONG TERM /Tuesday through Sunday/...
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As of 235 PM Sunday... Conditions are expected to dry out on Tuesday as the upper low pulls further away and shortwave ridging builds over the region. As the low pulls away, the building ridge will keep the main storm track to our north and west, resulting in mostly dry conditions through the majority of the long term period. There are indications that the ridge may weaken some towards the end of the forecast period, allowing an uptick in mostly diurnal type convection. However, given the model disagreement (the GFS, which is known the break ridges down too quickly, breaks down the ridge, while the ECMWF holds strong), will just show a little increase in cloud cover and will bring in a slight chance of precip at the very end of the forecast period. Otherwise, temps will gradually warm up to above normal, from mostly lower 80s on Tuesday to mid/upper 80s for the remainder of the period.
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&& .AVIATION /18Z Sunday through Friday/... As of 135 pm Sunday... Ceilings varying between MVFR and low end VFR will persist across central NC through Monday as an upper level low drifts southward from the northern Mid-Atlantic to a position over southern Virginia/central NC by Monday. Bands of scattered showers will pivot around this mid/upper level feature, though occurrence at any of the TAF sites is small. These conditions expected to persist through Monday evening. Aviation conditions expected to improve by Tuesday as the upper level low pulls northeast away from our region. A drier air mass will overspread central NC, leading to a period of vfr through the rest of the work week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...RAH NEAR TERM...WSS SHORT TERM...RAH LONG TERM...KRD AVIATION...WSS

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