Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
040 FXUS62 KRAH 171655 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1150 AM EST Fri Nov 17 2017 .SYNOPSIS... High pressure will be overhead through this evening, then move offshore late tonight. A much warmer southwest flow will overspread the area Saturday, ahead of a cold front that will cross the region Saturday night. Chilly high pressure will return for Sunday through Monday. && .NEAR TERM /THIS AFTERNOON AND TONIGHT/... As of 1150 AM Friday... The skies were sunny with only a few high thin cirrus noted late morning across the region. Temperatures have been slow to warm under the chilly high pressure overhead. Forecast highs this afternoon are still expected to reach into the mid 50s to lower 60s (coolest north and northeast) and warmest across the south. Increasing high level moisture (around 325-335K) from the west tonight within strengthening upper northwest flow will bring increasing high clouds overnight, as the surface high drifts off the NC coast, with strengthening SW flow up to 25-30 kts at 925 mb evident over the NW CWA. Lows will be in the mid-upper 30s, coolest NE where the clouds will be thinner with lagging low level moisture and thermal advection. -GIH && .SHORT TERM /Saturday through Saturday night/... As of 225 AM Friday... A deep shortwave trough will shift quickly from the central CONUS early Sat eastward to the Mid-Atlantic and Northeast through Sat night, attending a well-defined surface cold front. A brisk low level flow will be strengthening and backing slightly from WSW to SW Sat/Sat night, which will draw higher PW and greater surface dewpoints into NC, so we`ll see tonight`s increasing cloud trend extend into Sat with skies becoming partly then mostly cloudy through the day. But no rain is expected Sat with the column remaining somewhat dry and weak to absent forcing for ascent until after nightfall. Despite the clouds, rebounding thicknesses with good mixing and prefrontal warm air advection should push temps up to above-normal maxes of 63-71. Strengthening SW flow through a deep layer ahead of the surface front and mid level trough will push PW values above 1.0", well above normal, and with the arrival of strong mid level height falls and improving upper divergence along with a 50+ kt 850 mb jet, the earlier likely pops sweeping across the area Sat night still appears justified. However, the quick-hitting nature of this system and the short window of low level moisture transport will greatly limit amounts, and most locations will see a tenth of an inch or less, with the higher values mainly in the northern sections, closer to the more intense dynamics (much of which will pass to our N). Will not have any thunder in the forecast, given the very low and short-duration forecast MUCAPE values (under 200 J/kg). Showers should be exiting the eastern CWA toward daybreak, as the cold front lags just behind, crossing the forecast area late. Lows are expected to range from the low 40s NW to the low 50s SE. -GIH && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 250 AM Friday... A cold front will exit to the east early on Sunday morning, leaving drier and cooler weather in its wake. This will lead to dry northwesterly winds a bit breezy at times on Sunday afternoon around 10 kts gusting to 15-20 kts. Winds will relax on Monday. Temperatures during this time frame should top out in the mid 50s with low temperatures near or slightly below freezing. A warming trend will begin on Tuesday as surface pressure moves offshore and an upper level trough sits to the west of the region. This will stack southwesterly winds through the column and bring warm air advection into central NC. Highs near 60 degrees with lows in the upper 30s to low 40s. On Wednesday the upper trough will cross the area and moisture from off of the Carolina coast will try to advance northward into central NC. With the increased upper level forcing, can`t rule out a slight chance of a shower or two but very inconsequential. Highs in the upper 50s to low 60s. A dry cold front will move through Wednesday night bringing in a cooler airmass for the end of the work week. For Friday, attention will turn to a low pressure system moving out of the Gulf of Mexico and across the Florida peninsula that may spread moisture northward into the area but models are split on whether or not this will be the case. && .AVIATION /12Z Friday through Tuesday/... As of 630 AM Friday... Confidence is high in dominant VFR conditions across central NC over the next 24 hours. Surface high pressure and a dry air mass will build over the area from the northwest today, bringing unrestricted vsbys and no cigs. The surface high will shift offshore tonight as a few weak upper level disturbances approach from the west, and these will bring an increase in high clouds starting late in the TAF valid period. Surface winds will be from the northeast today under 10 kts, although some gusts over 10 kts are possible early this morning as a weak cool front drops through the area. Winds will trend to light and variable late today into tonight. Looking beyond 06z Sat: VFR conditions will hold through Sat, with increasing and thickening high and mid clouds. Surface winds from the SW will strengthen after daybreak Sat, to sustained 12-20 kts gusting occasionally to around 25 kts through the day. A short period of MVFR cigs/vsbys in showers is possible Sat evening and night as a cold front crosses the area, resulting in a shift of winds from SW to NW Sat night. VFR conditions are expected starting Sun morning as high pressure returns, lasting through Tue. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...Badgett SHORT TERM...Hartfield LONG TERM...Ellis AVIATION...Hartfield

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.