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
604 FXUS64 KJAN 100131 AAB AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 831 PM CDT Thu May 9 2024 ...New MESOSCALE UPDATE, AVIATION... .MESOSCALE UPDATE... Issued at 813 PM CDT Thu May 9 2024 Anticipated severe weather event continues to unfold across our region this evening. Analyzed MLCAPE values near or exceeding 4000 J/kg are supported by this evening`s KJAN sounding. A robust and unstable layer over very warm, humid boundary layer air mass has set up the ingredients for fast-growing and powerful thunderstorms as the cap is broken. Primary driver for new storm development at this time is increasing moisture convergence along outflow boundaries and the frontal boundary in our forecast area, as well as from the anticipated congealing outflow boundary from activity to our west (East Texas/western Louisiana). With the axis of greatest instability (4500 J/kg MLCAPE) extending west to east generally between the I-10 and I-20 corridors, and with deep- layer wind shear from the west at 60kts, any storm cluster or linear elements should find a favorable environment to continue spreading eastward. The threat for wind gusts over 80 mph and hail up to golf ball size remain the primary concerns tonight with any of the severe thunderstorms. /NF/ && .DISCUSSION... Issued at 317 PM CDT Thu May 9 2024 Through Friday: ...Severe Weather Expected Tonight... Mid afternoon surface analysis had a cold front nearly along a Tupelo to Greenville Mississippi line. South of the cold front temperatures have reach 90F with dew points in the mid to upper 70s. These conditions were resulting in heat index values in the lower 100s and many sites will peak near 105F. These conditions were also resulting in surface based CAPE values in excess of 5000l/kg. Local radars were still quiet in our CWA thanks in part to the capping noted on the 12Z Thu JAN sounding but regional satellite imagery and radars showed deep convection developing over the Red River valley with a disturbance noted over central Texas that is expected to help develop the convection into an mcs that will sweep east across our region this evening and several hours after midnight. There is a low chance that an isolated storm or two may develop and become strong to severe this afternoon ahead of the main event but overall, very little has changed from the previous thinking. An Enhanced Risk(3 out of 5) of severe storms remains outlooked for our CWA along and south of Highway 82. Damaging wind gusts of 80mph will be the main threat but hail up to the size of golf balls will also be possible. In addition tornadoes cannot be ruled out and locally heavy rainfall of one to two inches in a short amount of time will be possible. Model consensus suggests that the mcs will be moving into our western most zones during the early evening and exiting our eastern most zones by 3AM. Although the severe threat will end by 3AM, the cold front will be moving through our CWA and some anafrontal rainfall will prolong rain chances into Friday morning. As the cold front continues shifting southeast of our CWA, much drier and cooler air moving into the region in its wake will bring an end to the rain before noon. Afternoon highs will be cooler and held into the 70s across our north with low to mid 80s across our south. /22/ Friday night through late next week: Our area will continue to be influenced by an active perturbed pattern, which will keep rain and storm chances in the forecast. We start off quiet this weekend in the wake of the Thursday night system as flow turns northwesterly. Conditions will turn quite pleasant this weekend as dewpoints only remain in the 50s. This won`t last long however as our next disturbance quickly advances. Unlike the previous disturbance, the positive tilt and dry airmass will likely not give enough time to recover a moist airmass, thus a more suppressed system. That said, the parameters may be supportive of isolated strong to severe storms, especially given moderate to strong deep shear, so a severe graphic may eventually be needed down the road if trends persist. There could also be some heavy rain associated with this system, especially given PWAT anomaly as moisture attempts to recover. However, northern extent is uncertain at this time. Several weak disturbances will follow for mid next week with persistent rain and storm chances. Thursday/Friday disturbance appears to potentially be more potent with a richer airmass and stronger shear. However, the positive tilt may tend to suppress this system as well, giving a more southern solution. Expect adjustments to the forecast as more details become available./SAS/ && .AVIATION... (00Z TAFS) Issued at 813 PM CDT Thu May 9 2024 Ongoing SHRA and TSRA across parts of the forecast area will continue to pose the risk for severe wind gusts at the TAF sites, with gusts over 65 kts possible with the strongest of storms before 09Z. Patches of low stratus and variable visibility near storms will also lead to the possibility of MVFR or lower conditions. Winds should generally prevail out of the north with improving conditions for sites after 12Z Friday. /NF/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 67 80 57 79 / 80 10 0 0 Meridian 67 84 55 81 / 90 30 0 0 Vicksburg 67 82 59 81 / 80 10 0 0 Hattiesburg 70 87 60 83 / 70 40 0 0 Natchez 67 83 60 81 / 80 10 0 0 Greenville 65 80 59 81 / 50 0 0 0 Greenwood 64 79 57 80 / 60 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 22/SAS20/NF