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
911 FXUS62 KRAH 041824 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 205 PM EDT Tue Jun 4 2024 .SYNOPSIS... A series of mid-level disturbances will move east and interact with an unseasonably moist airmass over NC through Thursday. A pre- frontal trough and cold front will move across the area Thursday evening through early Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 1005 AM Tuesday... Latest satellite data shows clouds thinning in the NE region after a morning of heavy continuous rainfall across the region. The Flash Flood Advisory has been lifted as the rain has dissipated and shifted east. Reports estimated rainfall amounts of 2 to 4 inches fell in the northern portions of Nash county. No major updates to temperatures or dew points this morning and only minor updates to PoPs for this afternoon. Similar to yesterday, scattered afternoon showers and storms are expected to develop across the region with pulse like storms at which, some could be strong to border-line severe with strong winds and heavy rainfall. Highs today will be around 5 degrees above average ranging from mid 80s NW to around 90 in the south/east. As of 350 AM Tuesday... Hot and humid, with a ~30-40 chance showers/storms maximized this afternoon-evening. A weak upr-level/tropopause-based disturbance now centered over the wrn Carolinas will move sewd and off the SC coast later this morning. A mid/upr-level ridge will otherwise continue to extend across the Middle Atlantic, while a couple of MCVs now over MS will track along its wrn periphery and across the TN Valley today and the srn Appalachians and wrn Carolinas tonight-early Wed. At the surface, high pressure centered near and south of Bermuda will extend wwd and across the South Atlantic states, while a weak backdoor cold front/trough will move swwd along the Middle Atlantic coast and reach sern VA and perhaps the nrn Outer Banks of NC. Additionally, an outflow boundary and focus for ongoing showers over the ne NC Piedmont and nrn Coastal Plain may linger today. Daytime heating, into the mid 80s to around 90 F, of a humid airmass characterized by surface dewpoints mostly in the mid-upr 60s, will favor moderate destabilization and minimal cinh by this afternoon. Weak and somewhat nebulous forcing mechanisms, including the outflow boundary noted above and probably others from Monday`s convection, will tend to focus pulse-type showers/storms amid weak wly steering flow again this afternoon, most of which should dissipate with loss of heating through this evening. The exception will be across the far srn/wrn NC Piedmont, where forcing related to the approaching MCVs from MS may either maintain some degree of upstream convection or encourage new development there. It will otherwise remain muggy and mild tonight, with lows mostly in the mid-upr 60s. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 225 PM Tuesday... Upstream MCVs will continue to influence central NC`s sensible weather during this period as Bermuda high pressure remains in control. The first MCV, currently over central TN, will likely traverse central NC during the 1st half of the diurnal cycle. Isolated to widely scattered weak convection is possible as this feature moves through the area during what is otherwise poor diurnal timing. In the wake of the lead MCV, possible remnants of another MCV associated with the linear cluster over NE TX and lower MS Valley, could potentially move through the area during peak afternoon heating, with re-development of showers and storms from west to east across the area during the afternoon and evening. Deep layer shear increases slightly, but is still weak, and should mitigate the severe threat. Mean storm motion should also be higher than recent days, but given moist PWATs of 1.9-2.0", some localized flash flooding remains possible. Isolated to widely scattered showers/storms could linger overnight, especially with renewed lift from an elongated shortwave trough extending south from the mid- latitude cyclone over southern Ontario. Highs into the mid 80s to around 90 F, with some lower 80s possible over the NW Piedmont where the second round of convection could pop off earlier. Lows in the mid 60s to lower 70s with areas of stratus expected. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 330 AM Tuesday... By Thursday morning, an upper low will be over southwestern Ontario with a surface low a bit farther to the northeast. The surface cold front should extend southeast across the Great Lakes into Pennsylvania, then arc back to the southwest along the I-85/95 corridor. While some minimal changes were made to the area of likely shower coverage on Thursday, likely pops generally remain to the southeast of US-1. MUCAPE should be on the order of 1000-2000 J/kg, while effective bulk shear remains at or below 30 kt. Thursday also appears to be the warmest day out of the next seven, with west- southwesterly flow providing warm advection allowing highs to max out between the mid 80s and lower 90s. Although slight chance pops will continue from US-1 to the east Thursday evening, have continued the inherited dry forecast for Friday as the GEFS has finally come in line with other models showing all precipitation to the east of the region. Friday appears to be the day that noticeably drier air will arrive, with dewpoints dropping into the 50s (and upper 40s in the Triad). The dry forecast continues through Saturday into Sunday. Unfortunately, different runs of the GFS/ECMWF and their respective ensembles continue to flip-flop as to when the next front will approach the southeastern United States, so this part of the forecast has below normal confidence. For now, have slight chance pops Sunday night and chance pops everywhere Monday. The Thursday/Friday front won`t bring much change in high temperatures, with highs remaining in the 80s through the weekend. However, there will be some relief each night, with overnight lows in the lower 60s instead of the upper 60s. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... As of 205 PM Tuesday... Isolated showers and storms are beginning to develop across portions of the CWA, but ceilings are generally around 3k-4k ft over the Triad and 4k-7k elsewhere. Mostly VFR conditions are expected this afternoon and evening with the exception of periods when storms move over/near the terminals causing reduced vsby and ceilings. As the mid level disturbance moves across the region tonight and early morning, this could result in some flight restrictions early Wednesday morning ahead of the cold front. Outlook: Showers ans storms associated with a cold front that is expected to come through the region late Wednesday /Thursday will result in flight restrictions of MVFR or lower in some areas. VFR conditions are expected to return Friday through the weekend before another disturbance moves into the region early next week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...CA/MWS SHORT TERM...CBL LONG TERM...Green AVIATION...CA