Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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. --
000 FXUS62 KRAH 172331 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 731 PM EDT MON OCT 17 2016 .SYNOPSIS... Ridging at the surface and aloft will prevail through the majority of the work week. An upper level disturbance and attendant cold front will approach the region from the west Thursday night into Friday, at the same time a cut-off low and associated surface low pressure system are expected to retrograde westward from the Bahamas toward the Southeast coast. && .NEAR TERM /THROUGH TONIGHT/... As of 255 PM Monday... A 125-150 kt Pacific jet extending roughly west-east from northern CA through the Intermountain West/Rockies and into the Upper Midwest this morning will continue east into New England tonight. Meanwhile, an upper level low offshore the Southeast coast will stall /cut-off/ and meander in vicinity of the Bahamas tonight as an upper level ridge centered near the TX Gulf Coast builds NE through the Deep South into the Carolinas, anchoring surface high pressure offshore the Carolina coast and maintaining a surface ridge extending westward into the Southeast CONUS. The result will be quiet and fair weather with lows tonight in the mid/upper 50s. -Vincent && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 1200 PM Monday... Little change in comparison to today aside from additional height rises as the aforementioned upper level ridge builds eastward from TX to the Deep South, maintaining Bermuda high pressure and the dry surface ridge extending west onshore the Southeast/Carolina coast. Expect dry/benign weather to persist with temperatures rising a few more degrees in comparison to today, in the lower 80s (a good 10F above normal), lows Tue night near 60F. -Vincent && .LONG TERM /WEDNESDAY THROUGH MONdAY/... As of 255 pM Monday... Wednesday and Wednesday night...a ridge aloft centered over southern AL/GA will ridge northeast into the Carolinas while surface high pressure over the western Atlantic will ridge west into NC/VA. A dry and rather warm air mass across the region will be characterized by low precipitable water values of around 1.0 inches and morning low-level thickness values of 1395-1400m. The result will be mainly clear skies with a period of early morning fog/stratus possible across the Coastal Plain. High temperatures will warm into the mid 80s in most locations, which will be around 15 degrees above normal. Record highs for Wednesday (10/19) include 86 at GSO, 86 at RDU, and 90 at FAY. Lows Wednesday night will fall back into the lower 60s. The weather pattern will become more active for Thursday through Friday night as northern stream energy drops into the central Plains on Thursday and heights begin to fall across the Carolinas. NWP guidance in fairly good agreement that a higher amplitude trough sets up near the central Mississippi river on Thursday evening. Guidance then diverges in the handling of this system with the 12Z ECMWF aggressively pushing the trough and the associated cold front across central NC Friday morning with little/no precipitation while the GFS is slower, more amplified with the upper trough, eventually pushing it across the Carolinas in a negatively tilted fashion with a few tenths of an inch of precipitation. Further complicating things is an upper level low pressure system near the Bahamas that the National Hurricane Center now notes has a 60% chance of developing into a tropical or subtropical cyclone late in the work week as it moves slowly north or northwest. A slower arrival of the upper trough (per the operational GFS) would allow this system to get closer to the Southeast coast and possibly bridge some moisture into the area. WPC prefers the more progressive (ECMWF) solution which would result in a more benign system for central NC. Given this we have lowered PoPs a bit with a low chance or slight chance of showers in the forecast for Friday and Friday night. Highs on Thursday will range in the lower 80s and highs Friday will range in the lower and mid 70s with lows Friday night falling into the upper 40s to lower 50s. Quiet but cooler weather arrives for the weekend and Monday as northwest flow aloft develops on Saturday and persists into Monday. Surface high pressure will slowly build into the region on Sunday and Monday. It will be chilly on Saturday with highs in the lower to mid 60s along with cool northwest wind at 10 to 15 MPH with gusts up to 25 MPH. It will turn quite chilly on Saturday night with lows in the lower to mid 40s expected. Temperatures could be even chillier if the winds relax and optimal radiational cooling conditions develop. Fair weather and a slow moderation of temperatures is expected on Sunday into Monday with Monday`s highs ranging near normal from 69 to 74. -Blaes && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 730 PM Monday... 24 Hour TAF period: VFR conditions are generally expected to continue through the 24 hour TAF period as high pressure at the surface and aloft continues to provide the area with dry weather and mostly clear/mostly sunny skies. However, with light and variable to calm winds again tonight along with clear/mostly clear skies, we could again see some patchy sub-VFR visbys. KRWI stands the best chance of seeing any sub-VFR conditions, similar to last night. Any sub-VFR conditions that develop are expected to be quickly dissipate with sunrise. Outlook: Aside from the possibility of a short period of early morning fog each morning expect mostly clear skies and light/ variable winds through the majority of the work week as ridging prevails at the surface and aloft. The next chance for sub-VFR conditions will be Friday/Friday night when an upper level trough and attendant cold front are expected to progress east across the Carolinas/Mid-Atlantic and a low pressure system attendant a cut-off low offshore the Southeast coast is expected to retrograde westward from the Bahamas toward the Carolinas, however, forecast confidence remains below average in this period.
-- End Changed Discussion --
&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Vincent NEAR TERM...Vincent SHORT TERM...Vincent LONG TERM...Blaes AVIATION...BSD/Vincent is the U.S. government's official web portal to all federal, state and local government web resources and services.