Sunrise 6:16 AM   Sunset 7:48 PM Moonrise 2:32 AM   Moonset 2:05 PM

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FXUS64 KJAN 030258 AFDJAN

Area Forecast Discussion National Weather Service Jackson MS 958 PM CDT Thu May 2 2024

New MESOSCALE UPDATE

MESOSCALE UPDATE
Issued at 958 PM CDT Thu May 2 2024

Rest of tonight...

Evening water vapor/RAP/synoptic analysis indicate persistent southwesterly flow/ascent from shortwave off to the west over central TX. Bermuda high/mean ridge is centered off the Atlantic seaboard, keeping moistening southwesterly flow. There are likely remnant MCVs & subtle mesoscale features in this environment, with one likely driving a batch of persistent, light-moderate rain showers across the Delta region. Instability has waned some & ascent is subtle, so not expecting thunder. Global guidance & convective allow models (CAMs) are struggling with the evolution of any convection across the ArkLaTex & how that propagates towards the ArkLaMiss. Main changes to adjust PoPs up to 60-70% in the Hwy 82 corridor, but expect this to be short lived through around midnight & then becoming isolated-scattered in coverage.
Even though confidence is low in this scenario, scattered to numerous showers could move in closer to daybreak, mainly for areas along & northwest of the Natchez Trace corridor. Some patchy fog is also possible southeast of the Natchez Trace, into the Pine Belt to I-59 corridor. However, widespread low stratus is expected overnight & with some wind, not expecting much in the way of fog potential. Much lower HRRR dense fog probs than last night, more confident that we won't have problems overnight. Main sensible weather element change was to bump up PoPs towards consensus/radar trends. Updates are out. /DC/

DISCUSSION
Issued at 305 PM CDT Thu May 2 2024

Tonight into Thursday May 9th...This afternoon, we have the decaying/remnants of the morning MCS over the W half of the area.
The left-over MCVs are identifiable on radar "spinning" and helping to kick off some shower/iso storm activity on the N and SE periphery. Look for these trends to continue through the remainder of the afternoon, but we will still see limitations due to lack of more quality moisture return. Overall, the near term part of the forecast remains a challenge as meso-scale elements are a huge driver right now. Hi-res CAM guidance helps us much of the time with detail and great timing...but this regime is not one which they perform well. So, with such guidance struggle so much, having confidence in specifics or in overall PoPs is not very good. One such result is PoPs for tonight. It was quite high (60-80%) in the NW/N...but current trends and limitations noted earlier, favor much less in the way of rain/storm chances. Due to this, PoPs were lowered quite a bit from the starting guidance.

Friday, again...not much confidence as guidance has high PoPs for much of the area. We will see a wave (likely remnant MCV) or possibly a decaying MCS again. CAM guidance is a bit all over the map and there's a decent signal from the global models for precip.
The end result is overall medium to high PoPs (60-80%) for Friday. I can't argue against this and those seem sufficient until clarity comes into play more, which may not be until later tonight, early Friday.

For the weekend, Sat-Sun, warm and above normal conditions will continue, along with mid-range PoPs (30-50%). This is a result of our region being near a boundary and having an opportunity to get moisture return back across the area. Also, we remain in the perturbed flow regime with waves/MCVs tracking eastward from the big convective systems from TX. For the most part, this or any activity looks typical/routine, but it's early May and we could sneak a day in there with good lapse rates which would boost instability. Storm hazard analysis will need to be a day by day process through this weekend and update as needed.

Next week...look for a pattern shift as we will see more ridging in place starting Monday with a predominant warm anomaly in the lower levels as S/SW lower level flow locks in with the large surface high getting established across the SE coast toward Bermuda. Such a regime will result in mid to upper 80s with lower 90s by mid week in a good portion of the forecast area. The larger scale pattern won't persist too long as we will see a powerful system push out of Rockies later Mon into Tue. This will keep us in that "ridge" type regime into mid-week, but there will be another pattern adjustment overall. The powerful system looks to carve out a anomalous mid/upper low over the central US with resulting lower heights. This will in-turn increase the height gradient over the Mid-South and southern US supporting increased mid/upper level winds in a quasi- zonal regime. A surface boundary looks to migrate southward as well, esp by late week
So, what does all this start to mean
such a pattern looks to favor an active severe weather period sometime from later Wed into early Sat. Global guid is catching on to this pattern, but there's expected timing differences. At a minimum, support is increasing for at least one round of severe storms but this could easily result in more than one before a strong cold front for May pushes through. Instability has the potential to be quite high due to steep lapse rates and I already noted the potential for fast mid/upper level flow, which will only help organize things.
This is in the Day 7-9 range and remember the uncertainty in timing.
Just wanted to bring attention to the potential in advance. /CME/

AVIATION
(00Z TAFS)
Issued at 651 PM CDT Thu May 2 2024

Other than a few SHRA ongoing near GLH & approaching GWO in the VC, SHRA isn't expected to be a concern through most of the overnight period. Onset of low ceilings will be between 02/06-09z, starting at MVFR then lower down to IFR-LIFR, with most restrictive flight categories (i.e.LIFR stratus & some fog/BR) at PIB/HBG near daybreak 02/11-14Z Friday. Expect improvements to MVFR-VFR into mid-morning to early Friday aftn, when increased SHRA & iso TSRA are psbl. Light southerly sfc winds, generally up to 10mph & brief gusts up to 20mph, are psbl through the end of the 00Z TAF cycle. /DC/

PRELIMINARY POINT TEMPS/POPS
Jackson 67 79 64 85 / 30 70 30 30 Meridian 67 84 64 87 / 20 60 30 40 Vicksburg 67 79 64 86 / 30 80 30 30 Hattiesburg 68 83 65 89 / 20 40 20 20 Natchez 67 79 64 86 / 20 70 20 20 Greenville 69 79 66 84 / 60 80 40 40 Greenwood 68 79 65 84 / 60 80 40 50

JAN WATCHES/WARNINGS/ADVISORIES
MS...None.
LA...None.
AR...None.

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