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
276 FXUS62 KRAH 130046 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 845 PM EDT Sun May 12 2024 .SYNOPSIS... High pressure will build across the Southeast and Mid Atlantic region tonight and shift off the Southeast coast through Monday. A storm system will move in from the west Monday night through Wednesday, bringing unsettled weather. Weak high pressure moving in briefly for Thursday will be quickly followed by another storm system arriving Friday. && .NEAR TERM /TONIGHT THROUGH MONDAY/... As of 845 PM Sunday... Quiet and cool night on tap as high pressure remains over the southern Appalachians. Any residual nwly sfc flow will subside next hour or so, allowing for some radiational cooling ahead of upstream cirrus. Cooling will be strongest across the central/northern Piedmont where temps will dip into the mid to upper 40s. Further south along the NC/SC border, upstream cirrus will start to trickle in shortly, which will likely cap lows in the lower 50s there. Otherwise, expect dry and quiet weather tonight. Previous discussion for Monday...The surface high will shift off the Mid Atlantic coast, resulting in the onset of a light SSE/S return flow late in the day. High and mid clouds will steadily move in from the WSW through the day as remnant MCVs or residual debris clouds from TX/Gulf convection pass over the Carolinas. But it will remain rain-free, with residual dry air in the mid levels (600-700 mb) and a lack of moisture transport through the low levels. With thicknesses expected to rise to near normal and less insolation than we`re seeing today, high temps should be similar, upper 70s to lower 80s. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... As of 145 PM Sunday... A closed upper trough over MO Mon night will become an open wave as it tracks eastward Tue and Tue night into the lower OH valley and parts of KY/TN. At the surface, guidance shows a Miller B low pressure tracking from east-central MO into the OH valley during this period. Downstream of the low, a warm front over GA/SC is forecast to lift northward Tue night. While there remain some differences with respect to track/intensity, models show a secondary low tracking NE along the NW Piedmont and along the VA border at this time. Rain chances will overspread the region overnight Mon night and especially Tue morning/afternoon as moisture transport and isentropic ascent maximize over the region. Precipitable water values increase to near record daily maximum values of 1.75 to 2.0 inches. While not a classic setup, there are some indications of a weak in-situ wedge that could set up over the NW Piedmont Tue as the secondary low tracks through. As such, most of the forcing north of the warm front will be isentropically driven but some thunder chances will exist across our southern zones, mainly south/east of US-64/US-1 in closer proximity to some surface based instability. Highs could be tricky in the NW with lots of low clouds/rain around. We lowered highs to the upper 60s in the NW and mid 70s in the far SE, but these may need to be lowered if trends favor a wedge setup. Rain chances appear to lessen Tue evening/overnight into early Wed as a dry slot moves in from the mid-level shortwave. However, lingering low-level saturation should favor drizzle/shower chances over portions of the area, and perhaps some fog. Lows will be in the low to mid 60s. Rainfall totals could range from half an inch to three quarters of an inch in the NW to three quarters of an inch to 1.25 inches in the SE by Wed morning. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 355 PM Sunday... A mid/upr-level trough over the cntl Appalachians vicinity at the start of the medium range will move across and offshore the Middle Atlantic through Wed night, during which time an accompanying surface low will move across and offshore the srn Middle Atlantic. A trailing cold front will move southeast and across cntl NC during the afternoon-evening Wed. Progressive shortwave ridging aloft and underlying, weak surface high pressure will follow for Thu-Thu night. A perturbed, srn stream-dominated pattern will then prevail through at least Sat, with a pre-frontal, Appalachians-lee surface trough in place Fri and the passage of a frontal low and cold front Sat-Sat night. Sensible weather related to the pattern described above will feature areas of light rain and drizzle Wed morning, followed by likely showers/storms along and ahead of the cold front Wed afternoon- evening. Veered and generally weak, unidirectional wswly flow suggests any associated severe weather risk will be low. Dry conditions will follow through early Fri, followed by at or above climo probabilities of showers and storms ahead of the the next system late Fri-Sat evening, and probably drying conditions by Sunday. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... As of 720 PM Sunday... VFR conditions will continue through the TAF period with a steady increase in upper level cloudiness expected tomorrow. Surface winds will remain light as they veer towards southerly by Mon afternoon. Looking beyond 18z Mon, VFR conditions are expected through Mon evening, although light sprinkles will begin spreading into the western Piedmont during the evening hours. Widespread rain with a high chance of sub-VFR conditions and increasing/shifting winds aloft will overspread the area from SW to NE starting Mon night, lasting through Tue afternoon. Rain should become lighter and more patchy Tue evening/night, but sub-VFR fog and low clouds should linger through Wed morning. A band of showers with brief sub-VFR conditions is expected to swingHartfield through Wed afternoon/evening. Areas of sub-VFR clouds are possible early Thu morning, otherwise VFR conditions will dominate Thu. Scattered sub-VFR showers and storms are possible Fri afternoon. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Luchetti SHORT TERM...Kren LONG TERM...MWS AVIATION...Swiggett/Hartfield