jaxjagman Posted December 26, 2021 Share Posted December 26, 2021 After 4-years of the last one, time for another thread to get going 7 4 Link to comment Share on other sites More sharing options...
nrgjeff Posted December 27, 2021 Share Posted December 27, 2021 Good call. Locking the previous thread also saves the December 10-11 outbreak as the most recent material. 12Z Monday Euro and GFS (globals) have more of a surface low than the NAM for Wednesday. At 60 hours the globals are more trusted than the NAM. Regardless of what the NAM does overnight to 48 hours, SPC should go Enhanced for Wednesday as Day 2. Additional strengthening of the low level wind forecast could open the door to higher probabilities, but we're not there at this time. Wednesday soundings have eerie similarities to those of Dec. 10-11 in that they have more low level CAPE than recent April setups. Any strengthening and backing of low level winds could be trouble. Also we have the instability to promote another around of activity along the east-west boundary (as opposed to needing a prefrontal trough) IFF the low level wind forecast strengthens. Saturday could be big, or trash out with an Arctic front surge. This reminds me of a big week in the Plains. Saturday oh Saturday! Prior Wednesday ends up the big day. 3 3 Link to comment Share on other sites More sharing options...
Albedoman Posted December 28, 2021 Share Posted December 28, 2021 Memphis tv stations will be on board Wednesday again tracking the supercells. Its coming like a thief in the night. This freakish warm severe weather has to end soon 1 Link to comment Share on other sites More sharing options...
yoda Posted December 28, 2021 Share Posted December 28, 2021 Large SLGT risk from TN into the mid South for Day 2. Interesting re the bolded below Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CST Tue Dec 28 2021 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE MID-SOUTH AND TENNESSEE VALLEY... ...SUMMARY... Severe thunderstorms are possible for portions of the Deep South into the Tennessee Valley. Large hail, damaging winds, and a few tornadoes will be possible. ...Synopsis... A mid-level shortwave trough can be seen off the Oregon coast early Tuesday morning. This shortwave will round the base of the large-scale trough to near the Southern High Plains by 12Z Wednesday and into the northern Great Lakes by Thursday night. This will overspread weak height falls across the warm sector during the day Wednesday. Meanwhile, a lee cyclone is expected to develop near the Oklahoma Panhandle Wednesday morning and move quickly eastward along the surface front through the day. Guidance has come into better agreement showing a closed surface low developing along the front, but there still remains some uncertainty in the exact location and strength of this surface low. ...Portions of the Mid-South and Tennessee Valley... A long-fetch Caribbean moisture feed will be in place across the Southeast on Wednesday morning with mid-60s dewpoints into southern Tennessee at 12Z. Low-level flow will strengthen in response to the developing surface low along the front Wednesday afternoon. This will advect higher theta-e air northward with mid 60s dewpoints into north central Tennessee and upper 60s dewpoints into portions of northern Mississippi and Alabama. Some breaks in the clouds are anticipated in this region as low-level cloud streaks advect northward across the warm sector, which may allow temperatures to warm into the mid to upper 70s. As a result, ample instability is anticipated across the warm sector, with MLCAPE in excess of 1500 J/kg possible as far north as Columbus, Mississippi. Thunderstorms will likely be ongoing at the beginning of the period near the Red River in southeast Oklahoma/northeast Texas in response to increasing isentropic ascent as the low-level jet strengthens. This activity is expected to continue northeastward through the day and may eventually overspread the warm sector, and become surface based. The marginal and slight risk have been expanded northward to account for this possibility given the favorable severe parameter space across much of the warm sector Wednesday afternoon. The primary severe weather threat will be focused on thunderstorms east of this activity in a region of broad, weak isentropic ascent where a confluence band could set up off the Gulf of Mexico. Expect storms to develop out of cloud streaks which will be streaming north through the morning. 00Z CAM guidance appears to be subdued in reflectivity and updraft helicity depiction. Forecast soundings in proximity of this convection would suggest more intense storm development than is currently shown. CAM guidance has had similar issues in past cool-season Southeast severe events, and therefore it could be a false depiction of storm intensity based on the environment. However, there are times when lackluster CAM reflection of storm intensity is hinting at a greater problem with forcing. This is at least somewhat of a concern given the mostly neutral height tendency across the region for much of the event. Any storms which develop in this region will encounter favorable vertical shear for supercells with effective shear in excess of 50 knots. In addition, the weakly forced nature of the convection will likely favor a mostly discrete storm mode. These storms should have a tornado threat, given the strengthening low-level jet, with a broad region of 40 knots of southwesterly flow at 850mb depicted by most guidance. This will yield effective SRH around 250 m2/s2 which will be more than sufficient for a few tornadoes. An upgrade to enhanced (10%/sig) was considered across northern Mississippi and northwest Alabama, but ultimately settled on an expansion of the slight risk for this outlook. If guidance continues to trend toward a stronger surface low, and if CAM guidance starts to show more intense storm development, an upgrade to enhanced may be necessary. ..Bentley.. 12/28/2021 1 Link to comment Share on other sites More sharing options...
yoda Posted December 28, 2021 Share Posted December 28, 2021 Also Friday and Saturday Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0404 AM CST Tue Dec 28 2021 Valid 311200Z - 051200Z ...DISCUSSION... ...Day4/Friday - Arklatex to the Mid-Mississippi Valley... A mid-level shortwave trough will move from near the Baja Peninsula Friday morning to the southern Plains by late Friday night. This approaching shortwave and deepening lee cyclone across the southern High Plains will elicit a strong mass response across the Arklatex late Friday and into Friday night. As the low-level jet strengthens, storm coverage is expected to increase in a broad zone of isentropic ascent north of a warm front from southeast Oklahoma to the Tennessee Valley. In addition to this elevated storm activity, most guidance also shows surface-based storm development on the warm side of the boundary Friday evening into the early morning hours Saturday. A very moist boundary layer will be in place ahead of this storm activity with mid-60s dewpoints as far north as southern Kentucky at 06Z Saturday. Therefore, convection will form and propagate into an unstable environment which will allow thunderstorms to continue through the overnight hours and into the Day5 period with a severe threat throughout. Strong deep-layer and low-level shear will support all severe hazards. ...Day5/Saturday - Mid South and the Tennessee Valley to the Southern Appalachians... Severe weather will likely be ongoing at the beginning of the period from the early morning thunderstorms across Arkansas and vicinity. There may be a slight lull in storm coverage/intensity during the diurnal minimum Saturday morning, as the lead wave continues northeastward and the primary trough approaches from the west. However, by midday, significant height falls will start to overspread the warm sector and widespread storm development is anticipated. The location of overnight convection will have a significant impact on the zones within the broader risk area where a higher severe weather threat will exist. However, all guidance shows a broad warm sector with a broad 50 knot low-level jet, which would foster an environment favorable for all severe weather types. The greatest uncertainties are related to the northward extent of the risk and the surface low track. Given the widespread convection expected north of the warm front, a convectively reinforced warm front could set up farther south than the surface low track may suggest. Also, global guidance still varies with the intensity and location of the surface-low as it tracks northeast. The track and intensity of this surface-low will have some impact on the storm evolution and intensity within the warm sector, especially as it relates to storm mode and the tornado threat. Maintained 15 percent probabilities from the previous Day 6 forecast with an expansion on the southern and eastern extent to account for the threat continuing late Saturday night. Link to comment Share on other sites More sharing options...
nrgjeff Posted December 28, 2021 Share Posted December 28, 2021 My take of the 12Z Tuesday guidance is after dark, but not super late. 12 hours ago, Albedoman said: Memphis tv stations will be on board Wednesday again tracking the supercells. Its coming like a thief in the night. This freakish warm severe weather has to end soon Short wave looks a little clumsy. I guess that's non-technical talk for odd ejection with poor low level wind fields. CAPE is high for this time of year, so any uptrend in low level wind fields would have to be watched closely. Look for heavy rain and some severe, but I don't think Wednesday evening will be too bad (if low level wind field forecast holds meh). 1 1 Link to comment Share on other sites More sharing options...
cheese007 Posted December 29, 2021 Share Posted December 29, 2021 D1 upgrade to ENH for northern AL/MS, parts of AR and TN Link to comment Share on other sites More sharing options...
Carvers Gap Posted December 29, 2021 Share Posted December 29, 2021 1 Link to comment Share on other sites More sharing options...
nrgjeff Posted December 29, 2021 Share Posted December 29, 2021 Thanks MRX I'll look forward to that sh!t after dark. At least it'll still be evening, not late night. Remember even storm chasers don't like that crap after dark. Virtual chase target is northeast Mississippi to northwest Alabama, into southern Middle Tenn. That's hideous chase terrain so no real chasing. Lunch in Corinth, Miss. would offer options south into Miss. or back east into Bama. However the immediate tri-state (with TN) is completely unchasable terrain. Punt! Oh yeah, lots of college football on today too. Cheers! 4 Link to comment Share on other sites More sharing options...
nrgjeff Posted December 29, 2021 Share Posted December 29, 2021 Boundary, clearing skies, and increasing surface winds has reached the Tennessee border with Mississippi and Alabama. Watch is valid. Another Southern event looks poised to over-achieve relative to 36 hours out. Still think Enhanced 10% hatched covers it. Not quite Moderate material, but it's getting close. I'd keep Enhanced. Word watches bluntly, but not strongly. In addition to the lifting boundary, appears a pre-frontal trough runs north to south in Mississippi. Could be a focus for robust new development. 1 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 29, 2021 Share Posted December 29, 2021 I've been impressed with how visible one of the boundaries is on satellite, pretty much all day: It almost follows the TN river 2 Link to comment Share on other sites More sharing options...
bamabonners Posted December 29, 2021 Share Posted December 29, 2021 Storms always follow the TN river... In my experience. 1 Link to comment Share on other sites More sharing options...
PowellVolz Posted December 29, 2021 Share Posted December 29, 2021 I've been impressed with how visible one of the boundaries is on satellite, pretty much all day: It almost follows the TN river Are you talking about in that area out west where the clouds are moving NW in that clearing area?. Link to comment Share on other sites More sharing options...
Indystorm Posted December 29, 2021 Share Posted December 29, 2021 Increasing cloud breaks and solar insolation will only up the ante for svr wx today in the affected areas. Link to comment Share on other sites More sharing options...
Coach B Posted December 29, 2021 Share Posted December 29, 2021 My temp has dropped into the upper 50s with steady rain in S mid TN. Sure doesn't have the severe feel?? 2 Link to comment Share on other sites More sharing options...
PowellVolz Posted December 29, 2021 Share Posted December 29, 2021 It definitely feels warmer in Knoxville. Wonder where the WF is?. Link to comment Share on other sites More sharing options...
PowellVolz Posted December 29, 2021 Share Posted December 29, 2021 Increasing cloud breaks and solar insolation will only up the ante for svr wx today in the affected areas.Clearing is rapidly moving north across the State line now. . Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 29, 2021 Share Posted December 29, 2021 48 minutes ago, PowellVolz said: Are you talking about in that area out west where the clouds are moving NW in that clearing area? . I was meaning the line I've drawn in blue. It was really interesting up here in MoCo this AM. Left my house for a run at Frozen Head and it was ~ 61 Got to Frozen Head (~5 miles N of my house) and it was a cool 57. It wasn't a huge temp drop, but distincvtive. 2 Link to comment Share on other sites More sharing options...
Indystorm Posted December 29, 2021 Share Posted December 29, 2021 Watch coming shortly for northern Alabama per SPC meso. I expect tornado watch. 1 Link to comment Share on other sites More sharing options...
Holston_River_Rambler Posted December 29, 2021 Share Posted December 29, 2021 You could really see it well on radar this AM, (this is not a current radar image) But like you said it's trying to lift back north now. 1 Link to comment Share on other sites More sharing options...
Indystorm Posted December 29, 2021 Share Posted December 29, 2021 First tor warning of today's episode back in Arkansas BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE LITTLE ROCK AR 246 PM CST WED DEC 29 2021 THE NATIONAL WEATHER SERVICE IN LITTLE ROCK HAS ISSUED A * TORNADO WARNING FOR... NORTHERN DESHA COUNTY IN SOUTHEASTERN ARKANSAS... NORTHEASTERN DREW COUNTY IN SOUTHEASTERN ARKANSAS... SOUTHEASTERN LINCOLN COUNTY IN SOUTHEASTERN ARKANSAS... SOUTHEASTERN ARKANSAS COUNTY IN SOUTHEASTERN ARKANSAS... * UNTIL 330 PM CST. * AT 245 PM CST, A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO WAS LOCATED 7 MILES SOUTHWEST OF MILLS, OR 10 MILES WEST OF DUMAS, MOVING EAST AT 50 MPH. HAZARD...TORNADO AND QUARTER SIZE HAIL. 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. * LOCATIONS IMPACTED INCLUDE... DUMAS... MITCHELLVILLE... WATSON... WINCHESTER... YANCOPIN... OMEGA... MILLS... MERRISACH LAKE... TRUSTEN HOLDER WMA... ARKANSAS POST... GARRETT BRIDGE... PENDLETON... GOURD... FLORENCE... TYRO... ROSE HILL... REEDVILLE... MORGAN POINT RECREATION AREA... YUKON... PICKENS IN DESHA COUNTY... Link to comment Share on other sites More sharing options...
PowellVolz Posted December 29, 2021 Share Posted December 29, 2021 I was meaning the line I've drawn in blue. It was really interesting up here in MoCo this AM. Left my house for a run at Frozen Head and it was ~ 61 Got to Frozen Head (~5 miles N of my house) and it was a cool 57. It wasn't a huge temp drop, but distincvtive. Well I could see that boundary you drew in blue but I thought maybe that was some kind of inverted trough on top of the mountains. . 1 Link to comment Share on other sites More sharing options...
Wintersnow888 Posted December 30, 2021 Share Posted December 30, 2021 We had a gust front go through about 18 minutes or so ago but hardly any thunder , just heavy rain Link to comment Share on other sites More sharing options...
nwohweather Posted December 30, 2021 Share Posted December 30, 2021 Lots of CIN really putting a lid on tonight. If it wasn’t for that, we’d have likely a significant outbreak tonight 1 Link to comment Share on other sites More sharing options...
SmokeEater Posted December 30, 2021 Share Posted December 30, 2021 Structural damage in downtown Winfield, AL from a tornado about 90 minutes ago. Sent from my SM-G973U using Tapatalk 1 Link to comment Share on other sites More sharing options...
nwohweather Posted December 30, 2021 Share Posted December 30, 2021 Could get interesting for sure Link to comment Share on other sites More sharing options...
AMZ8990 Posted December 30, 2021 Share Posted December 30, 2021 Lots of rain and some wind but that was about it at the Golf course in Collierville. Rain was really intense though for about 30 minutes, flash food intense! Other than that no thunder or lighting to report from my end of the state. Very powerful little system though Link to comment Share on other sites More sharing options...
nrgjeff Posted December 31, 2021 Share Posted December 31, 2021 Always Sand Mountain @SmokeEater Also saw a report from Rainsville, another common event. It's almost the Cullman of the Mountain. 1 Link to comment Share on other sites More sharing options...
AMZ8990 Posted January 9, 2022 Share Posted January 9, 2022 Had some thunder and lighting this morning on my way into work in Collierville. Rain is coming down HEAVY now. It’s Gonna be a gully washer for a lot of people as this system moves across the state today. 1 Link to comment Share on other sites More sharing options...
nrgjeff Posted January 21, 2022 Share Posted January 21, 2022 CFS and GFS weeklies are both trending toward the ECMWF weeklies, in that the second week of February may return to warmer than normal. Depending on the amount of toughing in the West and Plains -PNA? it will be time to think about early season severe weather and storm chasing. Waiting for the Plains has not been rewarding recent years. Chase everything in Dixie! Barring a sharply colder forecast change over the weekend, I'm about done in the winter threads. Chatty doesn't have a snowball in hell prayer early next week. Look for me in this thread. La Nina! Tee up early and often Southern severe!! 4 Link to comment Share on other sites More sharing options...
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