Let's continue here for tonight's weather that'll roll into tomorrow morning as well as Friday night's weather which currently has a very large Slight Risk.
TONIGHT:
OVERNIGHT HRRR:
FRIDAY NIGHT INTO SATURDAY MORNING:
Last Edit: Apr 7, 2021 6:46:25 GMT -6 by SKYSUMMIT
Looks like late Friday through the first half of Saturday. Saturday is looking pretty wet right now, but hopefully should begin drying up by the afternoon.
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Apr 07 2021
Valid 071300Z - 081200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ARKANSAS...NORTHERN LOUISIANA...WESTERN/NORTHERN MISSISSIPPI...AND SOUTHWESTERN TENNESSEE...
...SUMMARY... Scattered severe thunderstorms are expected from this afternoon into the evening across parts of the lower Mississippi Valley, Mid-South, Arklatex and Ozarks. Wind damage, hail and tornadoes will be possible.
...Synopsis... In mid/upper levels, a split-flow pattern will persist across the central CONUS, downstream from a strong trough digging southeastward from the AK Panhandle across BC and the Pacific Northwest. The feature responsible for that split is a meridionally elongated cyclone -- now apparent in moisture-channel imagery over the central High Plains -- with a basal vorticity max over southwestern KS. The primary 500-mb low should proceed east-northeastward across KS to the EMP/TOP area by 00Z, then eastward to near COU by 12Z.
At the surface, 11Z analysis showed an elongated area of low pressure along a frontal zone from western IA to eastern KS, with cold front southwestward across south-central OK and west-central/ southwest TX. A primary surface low should consolidate and deepen, reaching southwestern/south-central IA by 00Z, with cold front arching across eastern MO, northern to southwestern AR, and northeast to south-central TX. The low should move little overnight while becoming more deeply occluded. The cold front should reach western KY, middle TN, eastern MS/western AL, and southeastern LA by 12Z.
...Arklatex/Ozarks to lower/mid Mississippi Valley... See SPC mesoscale discussion 320 for coverage of a marginal, near-term hail concern ongoing in the Ozarks and vicinity.
Scattered to numerous thunderstorms are forecast to form today in an arc near the cold front -- initially from portions of western MO to the Arklatex region, then backbuilding/shifting over the Mid-South and Delta regions into this evening. Damaging winds, several tornadoes, and sporadic severe hail all will be possible in a broad swath from IA to parts of LA/MS, with the greatest severe potential in and near the "Enhanced" area.
The earliest development is expected from extreme eastern portions of KS/OK into near the MKC-FSM/northern I-49 corridor around midday. This should occur as the cold front encounters the northern fringe of diurnal boundary-layer destabilization and continuing warm-sector moisture advection. This will be overlain by increasing large-scale ascent related to a vorticity lobe pivoting around the southeast side of the mid/upper cyclone, preferentially eroding already weaker EML-related MLCINH compared to father south. As the front encounters even stronger boundary-layer destabilization (needed to overcome greater capping) southward into the Arklatex region, additional convection should develop into early/mid afternoon, perhaps extending as far south as east TX and western/northern LA by late afternoon.
The resulting, essentially continuous arc of thunderstorms will encounter a favorable inflow region, with surface heating and dew points in the 60s F contributing to a prefrontal corridor of 1000-1500 J/kg peak MLCAPE (locally/briefly higher). Buoyancy will be supported somewhat more by cold air aloft in the north and higher boundary-layer theta-e in the south. While the flow aloft remains difluent, height gradients will tighten over the near-frontal warm sector with the eastward shift of the cyclone aloft, along with some backing with time of midlevel flow. The net effect should be for strengthening deep shear (e.g., effective-shear magnitudes reaching 35-50 kt), but also, a more front-parallel component to winds aloft, encouraging quasi-linear storm mode with embedded supercells and bow/LEWP features.
The resulting MCS will encounter veering flow with height in low levels and favorable effective SRH for occasionally tornadic mesocirculations. The warm sector will be narrower with northward extent, leading to convection's outrunning favorable inflow sooner this evening in the mid Mississippi Valley region, and lasting well into the overnight hours across portions of MS, TN, LA and AL.
Tornado Watch Number 75 NWS Storm Prediction Center Norman OK 1240 PM CDT Wed Apr 7 2021
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of Much of Arkansas Northwest Louisiana Southeast Oklahoma Northeast Texas
* Effective this Wednesday afternoon and evening from 1240 PM until 800 PM CDT.
* Primary threats include... A few tornadoes likely with a couple intense tornadoes possible Widespread damaging wind gusts to 70 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible
SUMMARY...Thunderstorms will continue to develop along a cold front moving into the watch area. These storms are expected to become locally severe, with tornadoes, damaging winds, and hail possible through the afternoon.
The tornado watch area is approximately along and 90 statute miles east and west of a line from 65 miles west southwest of Natchitoches LA to 20 miles north northeast of Flippin AR. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings.
Mesoscale Discussion 0324 NWS Storm Prediction Center Norman OK 0222 PM CDT Wed Apr 07 2021
Areas affected...much of Arkansas...far southeastern Oklahoma...northeastern Texas...and northwestern Louisiana
Concerning...Tornado Watch 75...
Valid 071922Z - 072015Z
The severe weather threat for Tornado Watch 75 continues.
SUMMARY...The severe threat continues across WW 75.
DISCUSSION...A mix of linear and cellular convective cells continue to gradually deepen along a front that now extends from near FYV to FSM to PRX to south of TPL in northeast Texas. The storms are in a weakly capped environment, with most of the ascent tied to the advancing front, although cells over the open warm sector are also maturing. The storms are in a favorable environment for organization given 30-40 knots of deep shear and modest mid-level lapse rates supporting 1000-1750 J/kg MLCAPE. Low-level shear supports rotation, locally enhancing the risk for hail and tornadoes near dominant convection. The greatest severe threat over the next couple hours may evolve near convection that can strengthen nearer the warmer surface temperatures from Louisiana into southeastern Arkansas.
Farther southwest, convection may pose an isolated damaging-wind risk from Anderson to Robertson Counties in Texas along the front. Surface temperatures just ahead of these storms have warmed into the low 80s, supporting stronger buoyancy (near 2000 J/kg MLCAPE) though low-level shear profiles are a bit weaker compared to areas just to the east. It appears unlikely that a new WW or local extension will be needed in these areas due to the isolated nature of the threat, though trends will be monitored as the front continues to migrate southward in that area.
Post by Will - Ascension Parish on Apr 7, 2021 14:24:45 GMT -6
It's a pretty damn good assumption that anytime there's the threat of severe weather anywhere in the south, central Mississippi and central Alabama will be the bullseye.
SKYSUMMIT President | Director of OperationsAdministrator
Mesoscale Discussion 0326 NWS Storm Prediction Center Norman OK 0340 PM CDT Wed Apr 07 2021
Areas affected...much of Arkansas...northeastern Texas...and northern Louisiana
Concerning...Tornado Watch 75...
Valid 072040Z - 072145Z
The severe weather threat for Tornado Watch 75 continues.
SUMMARY...The severe risk continues along and ahead of a front across western Arkansas and northeastern Texas. So far, storms have a history of hail and a few wind gusts, but tornadoes remain possible through the evening.
DISCUSSION...The severe risk continues across WW 75. Cells along and ahead of the cold front (now from near HRO to DEQ to 25 NW CLL) have occasionally produced hail and exhibited rotation, which isn't surprising given the 7-7.5 C/km mid-level lapse rates and favorable shear profiles in place. In the near term, it appears that the greatest severe risk (including 1"+ hail stones and perhaps a tornado or damaging wind gusts) will exist with cells that can acquire rotation either along the front or with isolated cells ahead of the front. Cells over central Arkansas are migrating eastward toward areas that received sunshine earlier, and an uptick in severe risk may occur there through the afternoon, especially as low-level flow increases over the next 2-3 hours. Ascent from an approaching vorticity maximum near Tulsa, OK should also sustain the current severe risk over Arkansas during that timeframe.
Tornado Warning National Weather Service Shreveport LA 420 PM CDT Wed Apr 7 2021
The National Weather Service in Shreveport has issued a
* Tornado Warning for... Central De Soto Parish in northwestern Louisiana... Northern Red River Parish in northwestern Louisiana... Southeastern Caddo Parish in northwestern Louisiana... Southwestern Bienville Parish in northwestern Louisiana... Southeastern Bossier Parish in northwestern Louisiana...
* Until 500 PM CDT.
* At 420 PM CDT, a severe thunderstorm capable of producing a tornado was located 8 miles north of Mansfield, moving east at 40 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely.
* This dangerous storm will be near... Ringgold around 500 PM CDT.
Other locations impacted by this tornadic thunderstorm include Womack, Ninock, Carmel, Frierson, Crichton, Hall Summit, Caspiana, Kingston and Loggy Bayou.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris.
Tornado Warning National Weather Service Shreveport LA 431 PM CDT Wed Apr 7 2021
The National Weather Service in Shreveport has issued a
* Tornado Warning for... Southeastern Webster Parish in northwestern Louisiana... Southeastern Caddo Parish in northwestern Louisiana... Southwestern Claiborne Parish in northwestern Louisiana... Northwestern Bienville Parish in northwestern Louisiana... Southeastern Bossier Parish in northwestern Louisiana...
* Until 515 PM CDT.
* At 431 PM CDT, a severe thunderstorm capable of producing a tornado was located 9 miles south of Doyline, or 15 miles southeast of Bossier City, moving northeast at 35 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely.
* This dangerous storm will be near... Ringgold around 445 PM CDT. Heflin around 450 PM CDT. Sibley around 455 PM CDT. Dubberly around 500 PM CDT.
Other locations impacted by this tornadic thunderstorm include Curtis, Sailes, Lake Bistineau South, Noles Landing, Lake Bistineau North, Plum Orchard Landing, Ogden, Koran and Ada.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris.
Mesoscale Discussion 0328 NWS Storm Prediction Center Norman OK 0512 PM CDT Wed Apr 07 2021
Areas affected...Portions of eastern AR...the MO Bootheel...western TN...northern/central/western MS...and northeastern/central LA
Concerning...Severe potential...Watch possible
Valid 072212Z - 080015Z
Probability of Watch Issuance...60 percent
SUMMARY...A threat for isolated severe thunderstorms capable of producing mainly damaging winds and perhaps a few tornadoes may develop eastward this evening. Watch issuance is possible for parts of this area in the next couple of hours.
DISCUSSION...A rash of low-level warm advection driven convection has developed this afternoon across central/eastern AR and northern LA. With the exception of northwestern LA, recent radar trends suggest much of this activity is struggling to substantially intensify as it moves east-northeastward. Surface dewpoints in western TN and vicinity drop quickly into the low/mid 50s, with gradually decreasing instability with eastward extent. Furthermore, the VWP from KNQA shows limited veering in the boundary layer, which may tend to limit potential for low-level rotation. Farther south into northern/central/western MS and northeastern/central LA, greater moisture is present and stronger diurnal heating has occurred. Latest mesoanalysis estimates suggest up to 1000-1500 J/kg of MLCAPE exists across this region, and sufficient deep-layer shear should support organized updrafts. If storms can congeal into a better defined line ahead of the surface cold front, then the damaging wind threat would increase this evening. A few tornadoes also appear possible if storms can remain semi-discrete. This tornado potential may be slightly greater across northeastern/central LA into MS. Overall, the potential for a more substantial severe threat developing this evening remains unclear owing to the poorly organized convection across AR at the moment. Trends will continue to be monitored, and a watch may eventually be needed for parts of this region.