textproduct: Raleigh

WHAT HAS CHANGED

* Temporary visibility restrictions in shallow radiation fog/mist this morning have been introduced in the RWI TAF.

KEY MESSAGES

As of 145 AM Tuesday...

1) Unseasonably warm and dry through much of the work week, with record highs possible on Wednesday and perhaps Thursday.

2) A strong cold front will sweep across the area Friday with a significant cooldown for the weekend and the potential for some patchy frost.

DISCUSSION

As of 145 AM Tuesday...

KEY MESSAGE 1... Unseasonably warm and dry through much of the work week, with record highs possible on Wednesday and perhaps Thursday.

An upper level ridge will strengthen and shift ewd through the week, with the ridge centered over the Southeast US by Thursday. Surface high pressure will generally sit over the Southeast US through the week. Meanwhile, a trough will strengthen over the mid-Atlantic/NC as low pressure tracks ewd from the Great Lakes to the Canadian Maritimes through Wednesday. A backdoor front may approach central NC from the northeast Wed night/Thu as Canadian high pressure trails the aforementioned low, but still appears will stay generally north of the NC/VA border. The front should quickly lift away from the area as a rapidly deepening area of low pressure moves across the OH Valley and Northeast Thu night/Fri. 12Z low-level thicknesses today should be in the 1390-1400 dam range, increasing into the 1400-1410 dam range on Wed and Thu and possibly Fri. These thickness values will support highs in the mid 80s today, increasing to mid 80s to low 90s on Wed (about 15-20 degrees above normal), which would threaten/break record highs on Wednesday.

KEY MESSAGE 2... A strong cold front will sweep across the area Friday with a significant cooldown for the weekend and the potential for some patchy frost.

A potent nrn stream s/w aloft tracking ewd across wrn and cntl Canada Wed/Wed night will drop sewd across Ontario and the Great Lakes Thu and Fri, deepening the trough over the ern US as it interacts with another s/w ejecting enewd from the cntl Rockies. The trough will continue to deepen as it moves ewd across the region and offshore Fri/Fri night. At the surface, a rapidly deepening area of low pressure will lift newd across the OH Valley and Northeast Thu night/Fri, the trailing cold front moving across central NC late Fri/Fri night. The medium-range guidance still varies wrt precip chances with the fropa, the EC being the wetter solution but trending drier. The pressure gradient will be quite stout Fri/Sat as the low rapidly deepens near New England and strong ~1035 mb high pressure builds in from the west. The low-level jet is also expected to strengthen over the area Fri eve. Expect strong, gusty winds with and behind the front Fri aft through Fri night. The high may weaken ever so slightly as it builds ewd across the mid-MS and OH Valley regions, before settling over the mid-Atlantic Sat night/Sun and offshore by Mon.

By Saturday, highs will be similar to the lows from Thu night (generally low to mid 60s), while lows may drop some 10-15 degrees from Fri morn to Sat morn. However, the more significant drop in temps will come Sat night, as the high settles over the mid- Atlantic, when lows may drop into the mid/upr 30s across the nrn Piedmont and upper 30s to mid 40s elsewhere across cntl NC. Some patchy frost will be possible should the mid 30s lows be realized.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

As of 150 AM Tuesday...

Areas of shallow radiation fog/mist are likely to continue to develop and expand across the Coastal Plain/Tidewater of VA and adjacent NC Coastal Plain this morning, including at RWI where a crossover temperature of 60 F will likely be met within the next couple of hours. High pressure will otherwise build across cntl NC and favor VFR conditions and light swly winds today, after calm this morning.

Outlook: Aside from a chance of visibility restrictions in mist/fog at RWI and FAY Wed and perhaps again Thu morning, influence from high pressure over the Southeast will favor mainly VFR conditions over cntl NC for most of the upcoming week. An area of IFR-MVFR ceilings will develop behind a backdoor cold front and across VA and nrn NC Thu-Thu night, though the exact location of the front and post-frontal ceilings remains somewhat uncertain. A powerful cold front and sharply colder air will overspread cntl NC late Fri and Fri night, during which time a period of strong nwly surface winds may gust between 30-40 kts.

CLIMATE

Record High Temperatures:

October 14: KGSO: 85/1975 KRDU: 86/1985 KFAY: 90/1954

October 15: KGSO: 87/1985 KRDU: 88/1985

October 16: KGSO: 85/1953 KRDU: 86/1925 KFAY: 90/1925

Record High Minimum Temperatures:

October 15: KGSO: 63/1985 KRDU: 66/1942

RAH WATCHES/WARNINGS/ADVISORIES

None.