Area Forecast Discussion
Issued by NWS Jackson, MS
Issued by NWS Jackson, MS
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
508 FXUS64 KJAN 271158 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 658 AM CDT Thu Jun 27 2024 ...New AVIATION... .DISCUSSION... Issued at 441 AM CDT Thu Jun 27 2024 Today through tonight... Early this morning, water vapor/synoptic analysis indicate 595DM 500mb mean ridge persisting over the southern Plains to southwest while shortwave trough analyzed over the Gulf Coast states remains far south of more stout trough/jet energy across the Great Lakes. The aforementioned shortwave is driving in some drier air, around an inch & a half in GOES East total PWs in the extreme ArkLaMiss Delta, with some deeper moisture closer to the shortwave trough axis. There should be enough isentropic ascent/deformation along the back side of the shortwave to squeeze out some additional shower & isolated thunderstorm development into the aftn to evening hours. The best moist convergence will be in northeast MS & spreading to the south- southwest into the aftn to evening. Can`t rule out a stronger storm or two due to some deep flow around 20-25kts. Developing low stratus this morning will gradually mix out & aftn heating will be less prevalent than previous few days. Highs will be less seasonable, mainly in the mid-upper 80s across a majority of the area, with heat stress less of a concern, with heat indices peaking only around the mid 90s to around 100F. As heating wanes, convergence will not be able to maintain convection & any lingering showers should wind down by early evening. Lows will be seasonable in the low to mid 70s. Some patchy fog can`t be ruled out in the Golden Triangle in northeast MS, where HREF dense fog probs indicate some potential, but convective allowing models & fcst soundings aren`t as bullish. Sounding analysis indicate boundary layer mixing possible, which could keep more stratus rather than fog concerns. /DC/ Friday... The forecast for the extended period remains mostly on track with no major adjustments made to the overall forecast. As we head into Friday morning, global guidance shows a weak frontal boundary moving southeast towards the Gulf of Mexico. By Friday afternoon, the aforementioned boundary will remain stalled across coastal MS. This will allow for local PWATs to exceed 2 inches. Additionally, a deep layer ridge will build over the Lower Mississippi Valley. The combination of increased temperatures, along with southerly moisture flow across the region will help support sfc instability. As a result of this, scattered to numerous showers and thunder storms will occur across S/SE MS around this timeframe. As high pressure ridge builds in late week, dangerous heat stress will be the primary concern. Afternoon highs are expected to peak in the low/mid 90s with dewpoints climbing into the mid/upper 70s. This will yield heat indices in the 105 F - 110 F deg range. No changes have been made to the heat graphic for Friday, and an "Elevated" heat risk remains in place for southeast AR, northeast Louisiana and portions of northwest, central and southern MS. Heat headlines may be needed as we get closer. Saturday through Thursday... Hot temperatures will become more oppressive across our forecast area as global guidance highlights an upper-level high amplifying over Texas and gradually building across the Gulf Coast states into the southeast CONUS. This will bring oppressive heat and humidity across the area through the weekend into early next week. As we head into the new work week, global guidance shows the high pressure weakening, due to height falls from upper level system across the Great Lakes to northeast states. Heat will persist from the weekend into early next week, but increased rain and storm chances make areal configuration more uncertain. We maintained an "Elevated" heat in the HWO graphic Sunday and Monday, but an additional "Significant" area in HWO graphics for excessive heat was added to portions of the ArkLaMiss Delta in Chicot in AR southward to West- East Carroll and Madison in LA, to along and northwest of a line from Warren, Hinds northeast into Leflore to Grenada counties. These areas have seen persistent excessive heat, with less rain and storm chances Saturday before scattered to numerous coverage late weekend into early next week. However, excessive heat could be reached prior to convective initiation after midday, so kept it going through the weekend and some into early next week. Expect further updates to the heat graphics as we get closer to the weekend. Heat related advisories and excessive heat warnings will likely be needed as we get closer. A frontal boundary is expected to push towards the southeast, increasing shower/thunderstorm potential Sunday afternoon and Monday. The potential for severe weather is low around this timeframe, but there are continued signals in CSU machine learning probs for marginally severe storms Sunday into Monday. Rain chances will start to increase especially for areas southeast of the Natchez Trace into Tuesday. Isolated to scattered showers and storms will be possible later in the week with the best rain chances across southeast MS. /CR/DC/ && .AVIATION... (12Z TAFS) Issued at 658 AM CDT Thu Jun 27 2024 MVFR-IFR flight category ceilings are ongoing for a good portion of the region, while some LIFR ceilings developed at HEZ. Some light SHRA are developing early this morning & possible at a good portion of sites by mid- morning. As conditions warm up by mid- morning to midday, ceilings will improve to VFR. Best chance for impacts to local sites from aftn SHRA or iso TSRA again later today will be in central, eastern & southern TAF sites, while limited concerns at GLH, GWO & HEZ. Some additional MVFR ceilings are possible at GTR after 28/08-10Z. /DC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 86 73 91 76 / 40 20 20 10 Meridian 89 72 92 73 / 70 30 50 10 Vicksburg 88 73 93 76 / 20 10 10 0 Hattiesburg 91 74 93 76 / 70 40 60 10 Natchez 88 72 92 75 / 20 10 20 0 Greenville 89 72 94 78 / 10 0 0 0 Greenwood 88 72 92 76 / 20 10 10 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ DC/CR/DC