Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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
941 FXUS62 KRAH 282000 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 400 PM EDT Tue May 28 2024 .SYNOPSIS... A series of moisture-starved, reinforcing cold fronts will lead high pressure from central Canada and the Great Lakes to the Middle Atlantic and Carolinas this week. && .NEAR TERM /THROUGH TONIGHT/... As of 345 PM Tuesday... A synoptic trough stretching through a couple of shortwave perturbations over s-cntl ON and wrn PA/ern OH will continue to lift newd and across the Northeast and middle Atlantic, with associated glancing, ~20-30 meter/12 hr height falls across the srn Middle Atlantic (VA/NC) through this evening. At the surface, a front has moved/mixed ewd and become stationary over ern NC, near and just inland of see breeze and outflow along the coastal areas. Seasonably dry, wly flow has become established over cntl NC, between the front and weak high pressure building across the mid-South and TN Valley. Cntl NC will generally remain between isolated to widely scattered convection in a moderate instability axis along the front/sea breeze/outflow over ern NC, and other, diurnally-driven convection accompanying the aforementioned synoptic trough aloft over the Middle Atlantic/cntl Appalachians/lwr Great Lakes. Mainly diurnal cumulus over cntl NC will dissipate and yield to a mainly clear night, with low temperatures in the mid 50s to mid 60s. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 355 PM Tuesday... A shortwave trough now over WI/IA will dig sewd into the OH Valley tonight and then pivot across and offshore the Middle Atlantic Wed- Wed night. At the surface, an Appalachian-lee trough will develop with diurnal heating Wed and be overtaken by a moisture-starved, reinforcing cold front that will settle south across the Carolinas Wed night. Like that which is occurring with the shortwave trough pivoting across the Middle Atlantic today, diurnally-driven convection will likely redevelop and accompany the aforementioned shortwave trough that will pivot across the region Wed, with the greatest coverage from the NC/VA border nwd. While the forecast will remain a dry one for now, a slight/small chance of an afternoon shower/storm may be needed over at least the nrn NC Piedmont. It will otherwise remain less humid than recent days, and slightly cooler, with highs in the low-mid 80s and lows mostly in the 50s to around 60. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 232 PM Tuesday... A short wave trough pivoting across the eastern Great Lakes on Thursday will move off the Northeast and Mid-Atlantic coastal regions by early Friday and will be followed by sfc high pressure building into much of the Eastern US during the rest of Friday and into early Saturday. This high will bring with it a relatively cooler airmass into our region, which will result in high temps Thu- Sat in the upper 70s to lower 80s, which is several deg below normal. The main forecast challenge is whether or not the aforementioned s/w trough will have enough moisture or to work with across our area to result in any shower activity with it`s passage. The majority of the guidance suggests areas well north and east of Raleigh will have the best chance to see a passing shower late on Thursday or Thursday night, and the NBM keeps PoPs aob 14% across our entire CWA. For now will go with NBM keeping our forecast dry during that time (PoPs below 15%), but if PoPs continue to trend higher, they may be needed across our northeast and far eastern zones. Once the high moves offshore by mid-Sunday, look for a warming and moistening trend with temps near normal for the rest of the period. Both the GFS and ECMWF suggest a series of low-amplitude s/w troughs will transit the westerly upper flow and may provide enough forcing for some isold mainly diurnal shower/tstm activity late in the days Sunday through Tuesday, but certainly not a washout during that time with overall low QPF. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 155 PM Tuesday... Although a weak shower cannot be ruled out through this evening, as a mid/upr-level trough pivots across the Middle Atlantic, the likelihood of any impacting any one location in cntl NC --should one occur at all-- is less than 10 percent. The passage of another disturbance in cyclonic flow aloft will result in a slightly higher, ~10-15 percent chance of a shower over the nrn half of cntl NC Wed afternoon. Dry, wly flow will otherwise favor VFR conditions in cntl NC through Wed. Outlook: Canadian high pressure will build from cntl Canada to the middle Atlantic and favor VFR conditions in cntl NC through Sat. As the high shifts offshore, sly flow and increasing moisture will increase the risk of patchy fog and stratus Sun morning and a chance of showers/storms Sun afternoon-night. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...MWS SHORT TERM...MWS LONG TERM...np AVIATION...MWS