Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 271957 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 300 PM EST Mon Feb 27 2017 .SYNOPSIS... High pressure will move offshore today, followed by a warm front lifting through the area tonight. Meanwhile, warm southwesterly flow will continue ahead of a cold front approaching from the west through midweek. && .NEAR TERM /THROUGH TONIGHT/... As of 300 PM Monday... An area of showers extending from the SC Upstate through the Atlanta metro area is associated with a low amplitude trough crossing the Deep South. This feature should continue to move in an east- southeast fashion and weaken with time. The best lift associated with this system will remain south of our region. While we will see an increase in the mid-high level cloudiness associated with this feature, the bulk of the evening hours should remain dry across central NC. Eventually, increasing sly flow a few thousand feet above the surface will result in isentropic upglide of sufficient strength to trigger a few showers overnight, primarily along and west of highway 1. What showers that do occur will be spotty and brief in duration with amounts ranging from a trace to no more than a couple of hundredths. The considerable cloudiness tonight will act as a blanket and keep us several degrees warmer than last night. Overnight temperatures upper 40s to around 50 nw to the low-mid 50s southeast. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 340 AM Monday... West-southwest flow will ensue on Tuesday as a surface warm front lifts north of the area. Morning stratus will likely hold longest across the west but full heating is expected for a large portion of the area as period of high clouds spread east in relatively low amplitude flow. 1000-850mb thicknesses support highs in the lower 70s west to near 80 east. Dewpoints creeping into the upper 50s and modest 6.5-7 C/KM mid level lapse rates will lead to weak instability, but forcing is largely lacking outside of warm advection. Currently think showers and a few storms will be widely scattered across the Piedmont and coastal plain. Tuesday will be rather mild in the warm sector of a stronger low pressure system moving through the Midwest, with lows in the upper 50s and lower 60s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 235 PM Monday... Wednesday and Wednesday night: As the low pressure system over the Midwest moves eastward on Wednesday, the parent low will move over the Great Lakes region while the upper level trough/sfc cold front extending from the Great Lakes southwest through the ARKLATEX progress east toward the Carolinas. Over Central NC, continued warm southerly flow will persist through the day Wednesday as cloud cover and chances for convection increase from the west. Highs will range from mid 70s NW to low 80s south. South-southwesterly winds will be quite strong on Wednesday, sustained 15-20 kts with gusts to around 30 kts, strongest just before sunset and then again with the front. Latest model solutions continue to suggest the best chances for convection (shower and possible strong thunderstorms) will move into the west late Wednesday evening, quickly moving eastward through Central NC by early Thursday morning. Despite the poor diurnal timing of the axis of convection the high (uni-directional) shear and low (500-1000 J/Kg) CAPE will result in the slight chance for thunderstorms to produce some damaging winds as they move through the region. The likelihood decreases with time as the showers progress through the area. Wednesday night, winds will become more northwesterly, cold air advection will commence and skies will begin to clear. As a result of current fropa timing, low temperatures will range from mid 40s NW to mid 50s SE. Winds will continue to be breezy overnight (10-15 kts with gusts to around 20 kts). Thursday through Monday: This period is expected to remain dry. Highs Thursday and Friday will still be in the upper 50s to mid 60s, lows Thursday night in the mid 30s. A reinforcing dry cold front will push through late in the week with the coldest temperatures (mid 20s to around 30 degrees) expected Friday night/Saturday morning as the surface high moves overhead. Highs Saturday will be the lowest of the period, mid to upper 50s. Expect moderating temperatures once again for the remainder of the weekend and into next week as yet another low pressure system develops out west and the flow over the Carolinas becomes increasingly southerly. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... As of 1250 PM Monday... There is a high likelihood of VFR conditions across central NC through 03Z Tuesday. An area of high pressure at the surface will be positioned offshore by tonight while an area of low pressure drifts slowly west. The resultant circulation around these two weather systems will yield a sly flow. This flow will lead to moisture increasing across the region overnight into Tuesday. This will increase the chance for low end VFR/MVFR ceilings, primarily across the western counties including the Triad terminals after 06Z Tuesday. In addition, there is a chance for a few showers overnight into the first half of Tuesday morning. An unsettled weather pattern across central NC through Wednesday night will lead to an increased risk for sub VFR conditions. Additionally, a tightening pressure gradient will lead to windy conditions Wednesday with gusts 30-40kts highly probable. Prior to that, there is a chance for low level wind shear conditions overnight Tuesday night, more so speed shear rather than directional shear. The approach and passage of a cold front late Wednesday and Wednesday night will also increase the risk for a few thunderstorms. At this time, VFR parameters appear highly probable Thursday through Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...SMITH NEAR TERM...WSS SHORT TERM...SMITH LONG TERM...KC AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.