Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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521 FXUS62 KRAH 270120 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 845 PM EDT Sun Mar 26 2017 .SYNOPSIS... A surface high pressure area will extend from Bermuda westward into the Carolin`s through Monday. A cold front will drift southward across central NC late Tuesday and Tuesday night. && .NEAR TERM /THROUGH TONIGHT/... As of 745 PM Sunday... The band of light rain showers continued to move east across the Piedmont and Sandhills this evening. Additional showers were developing over western NC and eastern TN associated with the weakening mid-upper level trough that was lifting out to the north of our region. This feature and associated moisture band will support the continuation of light showers into the Coastal Plain this evening before diminishing. QPF will be very light, only a few hundredths of an inch. Additional showers were developing upstream into the Southern Appalachians and Tennessee Valley. Most model solutions indicate the initial showers will continue to weaken, with the focus expected to shift to the Foothills and NW Piedmont for additional showers later. This activity is also expected to be light, with QPF of a tenth to a quarter inch possible, especially Triad region. As for sky and temperature forecasts, the skies are expected to remain mostly cloudy, except cloudy NW and partly cloudy SE. The increase in low level moisture with dew points into the 50s suggests that lower stratus are possible if not likely in the western Piedmont later tonight. Lows generally in the 50s to near 60, with the warmer readings in the west where the low level moisture and clouds will be most prevalent. && .SHORT TERM /MONDAY THROUGH TUESDAY/... As of 330 PM Sunday... Monday, mid/upper level low over the southern Plains, opens up and lifts into the mid MS Valley. A lead s/w ahead of this feature will approach central NC late Monday. This feature will aid to back the mid level flow, leading to moistening of the mid layers of the atmosphere. This lead s/w will cross our region late Monday, triggering scattered showers and t-storms. Convective parameters not too shabby for end of March with MLCAPE off the GFS 750-1000 J/kg. Effective bulk shear 20-25kts on the cusp of supporting organized convective bands. While cannot rule out an isolated severe due to hail, bulk of convection should remain below severe criteria. Extensive cloud cover early Monday should give way to periods of sun. The peeks of sun with near sfc flow out of the sw will boost temperatures into the 75-80 degree range. The lead s/w will exit our region late Monday night but will be followed by the main mid-upper level trough by early Tuesday. This will maintain a threat for scattered showers and a few thunderstorms Monday night into Tuesday morning. By Tuesday afternoon, greatest threat for scattered showers and a few storms will be along and east of highway 1. Convective parameters by Tuesday afternoon may support a locally strong or severe storm over the coastal plain and sandhills as MLCAPE recovers to 1000 J/kg, with effective bulk shear in the 30-35kt range. A warm air mass will maintain above normal temperatures Monday night and Tuesday. Overnight temps Monday night should be in the upper 50s to near 60. Max temps Tuesday upper 70s to lower 80s. If cloud cover remains extensive or shower coverage is greater than anticipated, max temps Tuesday could end up being 4-5 degrees cooler. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... As of 230 PM Sunday... Wed-Wed Night: With a shortwave ridge aloft, expect mostly sunny to partly cloudy skies with above normal highs in the mid/upper 70s. Thu: High pressure is expected to extend southward into the Carolinas Thu morning (in the form of a backdoor cold frontal passage) in association with height/pressure rises in the wake of an upper level low moving offshore New England into the Canadian maritimes. With low-level NE flow emanating from the cool Labrador current in NE portions of the state and an increased likelihood for cloud cover in SW portions of the state, temps Thu afternoon could be as much as 15-20F cooler than Wed afternoon. With the above in mind, have decreased highs to the mid/upper 50s west to lower 60s east. Thu night: Expect an increasing potential for rain from west-east between midnight and sunrise Fri as an upper level low progresses from the central MS river valley to the Ohio valley and low level flow backs/strengthens downstream over the Carolinas and Mid- Atlantic. Lows in the mid 40s to lower 50s, depending on rain /evap cooling/. Fri-Fri Night: Confidence in the evolution of the aforementioned upper level low, attendant sfc cyclone and associated warm/cold fronts at this range is low to begin with, let alone when a CAD wedge may be in place at the beginning of the period. All guidance continues to indicate precipitation, thus have increased precip chances to high likely (60-70%). From a pattern recognition standpoint, a potential for severe weather cannot be ruled out, however, little more can be said at this range in the forecast. The temperature forecast on Fri/Fri night is challenging to say the least. At this time will show the coolest temps in the Triad (highs in the low 60s) and warmest temps in the Sandhills and SE Coastal Plain (lower 70s). Expect clearing skies in the wake of a cold frontal passage Fri night, with lows in the upper 40s to mid 50s. Sat-Sun night: Expect a warming trend with dry conditions Sat in the wake of the aforementioned upper level low progressing offshore the Mid-Atlantic coast. A continued warming trend with dry conditions is expected on Sun as a shortwave ridge aloft tracks into the region from the west. -Vincent && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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As of 840 PM Sunday... 24 Hour TAF Period: High pressure will remain offshore through Monday, while an area of low pressure passes to the north of central NC. This will allow for a few weak disturbances to track across the area from time to time yielding some light showers (and perhaps a thunderstorm or two on Monday afternoon). We may see some MVFR/IFR stratus develop across the Piedmont (KGSO/KINT/KRDU) early Monday morning, before lifting from mid/late morning into the afternoon (lasting the longest at KGSO/KINT). Otherwise, expect a varying degrees of cloudiness, with light and variable winds overnight again becoming south to southwesterly on Monday after sunrise with a few gusts possible during the afternoon into the mid to upper teens. Outlook: A marginally moist and conditionally unstable air mass will result in periods of MVFR ceilings across the region through Wednesday. The lower ceilings will most likely occur between 10Z and 16Z. There is the possibility of a few showers and thunderstorms again late Monday night through early Tuesday afternoon. Near the heavier showers and storms, expect MVFR ceilings and MVFR/IFR visibilities. A cold front will drop southward through central NC Wednesday, then stall to our south. The approach of an upper level low will increase sly flow a few thousand feet above of the cool stable dome of air at the surface, leading to widespread MVFR/IFR parameters due to low clouds and areas of rain late Thursday into Friday.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...WSS LONG TERM...Vincent AVIATION...BSD/WSS

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