Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 211659 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 100 PM EDT Sat Apr 21 2018 .SYNOPSIS... Chilly high pressure will extend south through the middle Atlantic states through the weekend. Low pressure is forecast to track east across the Gulf Coast states this weekend, then turn up the eastern seaboard early next week. This will bring cool and wet conditions early to mid week. && .NEAR TERM /THROUGH TONIGHT/... As of 100 PM EDT Saturday... Surface high pressure was centered from the eastern Great Lakes into the Delmarva and Outer Banks regions early this afternoon. The ridge axis extended down the eastern seaboard into GA and FL. High pressure will gradually move off the Mid-Atlantic coast tonight allowing some modification in temperatures. A few cirrus clouds, if any, is expected through tonight. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 100 PM EDT Saturday... Forecast for Sunday and Sunday night remains on track. Surface high pressure is expected to be reinforced over the Great Lakes into New England, then down into the Mid-Atlantic states Sunday into Sunday night. This occurs as a "closed" circulation or mid/upper low will track east across the Gulf Coast states. There will be an increasing pressure gradient and wind associated with these features. There will be a very deep and moist sub-tropical connection that will be tapped and pulled NW into NC by late Sunday night as the mid/upper low approaches the TN valley region. Clouds will thicken and gradually lower Sunday night, as rain probabilities increase from the south and west. The rain should hold off until Monday, but areas near the NC/SC border may have some light rain or sprinkles after sunrise. Cloud cover will cap temperatures somewhat on Sunday, but keep them very mild Sunday night as the E-SE flow increases. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 335 AM EDT Saturday... ...Another widespread soaking rain expected Monday afternoon into Tuesday night... A very impressive plume of deep sub-tropical moisture is expected to be tapped from the Caribbean and southwestern Atlantic into the developing storm system, as it tracks slowly toward our region from the Gulf Coast states and Tennessee Valley Monday into Tuesday. Rain is expected to develop/overspread the southern and western areas of central NC Monday morning, then eventually envelop the entire region by late Monday into Tuesday. Models are in general agreement in the track/strength of the mid/upper low as it tracks from northern MS NE toward the upper TN valley by 12z/Tuesday, then slowly northward into the lower Ohio Valley by 12z/Wednesday. The surface low track still is more uncertain given the spread in the guidance, especially by Tuesday night and Wednesday. However, it appears that a very deep influx of subtropical moisture will be lifted up and over the warm/occluded front as the low pressure approaches SC/southern NC late Monday into Tuesday. QPF of 1.5 to 2+ inches can be expected, with the higher totals likely in the western Piedmont where the stronger lift associated with the mid level low will be aided by the long SE fetch of deep subtropical moisture up into the higher Piedmont. A flash flood watch may be needed early next week given the current wet antecedent conditions, but highly dependent on the track of the aforementioned storm. Regardless, it appears to be a wet and cool start to the week aided by rain, clouds, easterly winds, and at least some form of Cold Air Damming early in the event. The chance of rain and showers will decrease after the system lifts north of the region mid-week, though another quick moving s/w disturbance may swing through the area on Thursday/Thursday evening. This would allow for another chance for showers on Thursday/Thursday evening. High temps are expected to rebound to near normal by the end of the week, with highs in the 70s. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... As of 100 PM Saturday... 24 Hour TAF Period: VFR. surface winds less than 10 knots. Outlook: A low pressure system will bring MVFR/IFR VSBYS and CIGS in rain and fog across central NC Monday through Wednesday. Scattered showers and MVFR conditions are possible Thursday as a weak system moves the region. && .RAH WATCHES/WARNINGS/ADVISORIES... NC...None. && $$ SYNOPSIS...Badgett NEAR TERM...Franklin SHORT TERM...Badgett/Franklin LONG TERM...BSD AVIATION...Franklin is the U.S. government's official web portal to all federal, state and local government web resources and services.