Jackson, Mississippi

New DISCUSSION

• We are monitoring for heavy rainfall threat associated with a cold front late Tuesday into Wednesday, mainly west of I-55.
• The aforementioned front could also carry a low end severe threat, primarily damaging wind gusts.

The pattern becomes remains active over the next week with persistent longwave troughiness over the region and several shortwaves and strong jet energy. Intermittent low rain chances will stick around throughout the week, but the greatest chances concern a system anticipated late Tuesday into Wednesday.

The system will take shape late Sunday into Monday as a shortwave digs from over the Pacific NW and phases with subtropical jet energy to aid in the lee cyclogenesis off the Rockies. The corresponding surface low will rapidly deepen as it tracks across the great plains. This should create breezy conditions Monday as the pressure gradient tightens in response. Moisture return in response will push dewpoints up into the upper 60s near 70 ahead of its attendant cold front. The cold front should lag behind the surface slow so most low level forcing will be focused north. Storms will develop along the front west over Oklahoma and Texas and push into our area late Tuesday as the front approaches. Lightning probabilities continue to suggest weakening with eastward extent which makes sense as low level forcing weakens. This all acts to slow the front down and the storms along it will reside in an environment favorable for heavy rainfall with PWATs approaching 2 inches and moist convergence. Storm motions suggest training along the slow moving boundary. Rainfall amounts can easily stack up in this scenario. Some guidance is suggesting bullseyes anywhere between 4 and 7 inches in a short period. This threat will have to continue to be monitored.

There is a low end chance for isolated severe weather as well with this system, but secondary to flash flood threat. Linear storm mode and high shear low cape type environment suggest a primary wind/tornado risk, which would likely be isolated with greatest chances west of I-55 and the river. Heavy rainfall, as well as overnight timing, may dwarf this threat a bit however and limit instability. Still, it is worth monitoring.

Due to the secondary low development into Wednesday, moisture wrap around lingers, so low (15-20%) rain chances continue through Thursday. Additional rainfall amounts to generally under a tenth of an inch. The jet remains active and persistent moist trajectories may keep isolated rain chances around to end the week into next weekend. /SAS/

A few areas of MVFR stratus have developed across parts of south MS and south LA early this morning, and ceilings are expected to fall to IFR/MVFR across most of the area by around daybreak, with ceiling restrictions persisting throughout the day Sunday across much of the area. There will also be scattered SHRA and TS at times throughout the TAF period, potentially resulting in periodic visibility restrictions. /DL/

Jackson       78  62  80  63 /  60  10   0   0
Meridian      73  58  78  60 /  80  20   0   0
Vicksburg     80  62  82  63 /  70  10   0   0
Hattiesburg   79  61  81  61 /  50  20  10   0
Natchez       81  64  82  65 /  50  20  10   0
Greenville    76  61  79  64 /  80  30  10   0
Greenwood     73  59  78  62 /  80  10   0   0

MS

None.

LA

None.

AR

None.