Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250755 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 350 AM EDT Wed May 25 2016 .SYNOPSIS...Surface high pressure will extend into the region through Friday. Meanwhile, a storm system will develop over the sub-tropical Atlantic and drift toward the Southeast coast through the weekend. && .NEAR TERM /through tonight/... As of 350 AM Wednesday... height rises (90m at KGSO last evening) continue across much of the eastern US, while a surface high has become established off the Southeast coast. Moisture recovery is underway but will be slow with dewpoints only in the upper 50s today. A modest subsidence inversion noted on the 00Z/25th KGSO RAOB and weak instability will inhibit any convection today. There is a weak disturbance upstream that will drift over western NC and may weaken the cap a bit, but hi- res WRF/HRRR guidance keeps all convection over or west of the mountains today. H10-H85 thicknesses starting out about 15m higher than Tuesday morning suggest highs about 5 degrees warmer, 84-89. Conditions will again be good for radiational cooling tonight, the exception being the western Piedmont where patchy mid/high clouds associated with upstream convection may become mostly cloudy for a period late in the night. Lows in the upper 50s and lower 60s. && .SHORT TERM /Thursday through Thursday Night/... As of 350 AM Wednesday... While high pressure, both at the surface and aloft, will remain over the region on Thursday, increasing PW to near 1.5" and a little better instability (500-1000 J/KG) will support a better chance of convection, mainly in the western Piedmont from storms moving off the higher terrain. The environment won`t be supportive of organized convection, so the threat of any strong storms is low and will be limited to enhancement from steepening low-level lapse rates. highs again in the upper 80s. The GFS appears much too aggressive with convection continuing into Thursday night given that the ridge will begin to restrengthen in response to the subtropical system developing over the northern Caribbean. Instead, skies should end up mostly clear and lows will dip back into the low/mid 60s. && .LONG TERM /Friday through Tuesday/... As of 325 PM Tuesday... The main forecast concern during this period will be low pressure off the FL east coast on Friday, that is progged by both the GFS and ECMWF to lift north toward the Carolina coast over the weekend. The 12z ECMWF is now much farther south with the low compared to its 00z run, and is now in better agreement with the GFS, which shows the low center coming ashore somewhere along the SC coast. Both solutions suggest the chances for a prolonged period of cloudy and damp weather for central NC is increasing, thus will continue the upward trend in our POPs for the period from Saturday night through at least Monday. In fact, if the latest ECMWF solution verifies, it could possibly remain cloudy, damp (perhaps even wet), and breezy from Sunday right through Monday and even into Tuesday. For now, given the uncertainties and low confidence, will keep pops limited to the chance range Saturday night through Tuesday; but if you have outdoor plans this holiday weekend, you`ll definitely want to pay close attention to the forecast! && .AVIATION /06Z Wednesday through Sunday/... As of 155 AM Wednesday... As high pressure expands over the Southeast US, VFR conditions will prevail through the current TAF period with a light southwesterly wind. Showers and storms remaining over or west of the mountains today, with just some increase in mid-clouds from the west late tonight. Outlook: VFR conditions will prevail across central NC through Friday. Meanwhile, the chance afternoon showers and storms will increase, mainly across western NC, with adverse aviation much more likely by Sunday as a low pressure system develops off the Southeast coast. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLS NEAR TERM...BLS SHORT TERM...BLS LONG TERM...RAH AVIATION...BLS is the U.S. government's official web portal to all federal, state and local government web resources and services.