jaxjagman

National Weather Service Nashville TN 220 PM CST Sun Nov 4 2018 ...Main Concern Continues to be Severe Thunderstorm Potential Monday Night... .DISCUSSION...This afternoon, light showers were occurring over the west half of the area. Look for the light showers to move eastward through the evening. Rainfall amounts will continue to be light, with less than one tenth of an inch expected. The weakening front responsible for the showers was also producing gusty winds approaching 40 mph at times. The winds will diminish through the evening. Monday will start out cloudy across Mid Tennessee. On the large scale, a trough axis will be moving out of the Rockies with an elongated area of surface low pressure over the central plains. As the day progresses the trough will take on a negative orientation and the surface low will deepen as it gains more upper level support. As the surface low deepens, a cold front will take shape over the Mississippi Valley. Gulf moisture will surge northward ahead of the front helping to destabilize the prefrontal air. A few showers may develop over Mid Tn during the day, but most of the action will hold off until Monday evening, with the initial development occurring off to our west. Monday night, the deepening low pressure across the Midwest and Ohio Valley will drag a trough / cold front from the Mississippi Valley, eastward through Mid Tn late in the night. A tongue of rich, Gulf moisture ahead of the front will cause enough destabilization to achieve around 600 J/kg of mixed layer CAPE. A 50-65 kt low level jet will ramp up ahead of the cold front leading to 40 kts of 0-1 km shear and 45-50 kts of 0-3 km shear. The severe threat will be in the form of a QLCS capable of damaging straight line winds and a few tornadoes. Despite the overlap of impressive shear and modest instability, this is not a slam dunk event. Pre frontal convection could interfere with available instability. Also, the shear to instability ratio may be too great. But, if deep updrafts flourish, they will easily rotate, and low level SRH will be supportive of tornadogenesis. Timing still looks like storms will be approaching from the west around 8 PM, crossing Metro Nashville between 11 PM and 2 AM, and east of the Plateau around 5 AM Tuesday. Most of Mid Tn is now under an enhanced risk from SPC, partly for wind damage potential and partly for high SRH values that could contribute to tornado development/strength.

I have some crap maps,but i'm glad Accu switched from to the Control runs on the weeklies to the Euro itself.But even though it's more of a +EPO,if there would be HP building up South of the Aleutian Islands,this would promote a more -EPO and potentially flood us in with some colder air into Dec.,the pic is at the end of the run,Dec 3rd.It's all presumption at this point, but the look isn't bad IMO

SREF is up to 30% West and Central Valley

It has a more stronger capping inversion

The latest SWEAT index from this afternoons Euro in the Valley.In case you don't understand what the SWEAT index is,here's a link.The maps are 0Z AND 6Z Tuesday http://www.theweatherprediction.com/habyhints/304/

Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1201 PM CST Sun Nov 04 2018 Valid 051200Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE ARKLAMISS REGION NORTHEASTWARD INTO CENTRAL KENTUCKY... CORRECTED SIGNIFICANT TORNADO PROBABILITY TO 10% ...SUMMARY... Severe storms capable of damaging winds and tornadoes are expected mainly Monday evening and overnight from northern Mississippi across Tennessee and into central Kentucky. ...Synopsis... Within a broad area of cyclonic flow aloft across the CONUS, a shortwave trough will move from the ArkLaTex Monday afternoon northeastward across the OH Valley during the night. This wave will take on a negative tilt, with the greatest height falls/cooling aloft from northern AR into OH while height tendencies remain neutral overnight across the Gulf Coast states. Winds aloft will continually increase through the period, with strong large-scale lift mainly from TN northward toward the Great Lakes. At the surface, a broad area of southerly winds will allow a northward return of 60s F dewpoints from eastern TX into the lower MS Valley during the day, and into TN and KY overnight. This will aid in gradual destabilization which when combined with very strong shear profiles will support the potential for corridors of damaging severe storms. ...ArkLaMiss northeastward into Kentucky... The rapid warm advection and moistening from the south will likely lead to extensive low cloud cover over much of the area ahead of the cold front which will limit low-level lapse rates/heating. Therefore, most of the destabilization will be due to low-level moisture advection and cooling aloft. This will occur first across AR and southern MO during the afternoon, and elevated storms capable of hail are possible. Not until after 00Z will destabilization occur farther north and east across northern MS/AL, TN, and KY, where shear will be strongest. Storms are expected to intensify along the southern periphery of the warm advection storms, as the air mass becomes more supportive of surface based convection, likely near the AR/MS border. It should be noted that too much coverage of these earlier storms could push the greatest threat corridor east, or diminish it faster than expected from the west. The cold front will then increase lift as it emerges into MS, TN, and KY, with a QLCS likely. Both damaging winds and tornadoes will be possible, with tornado potential more heavily weighted toward areas with warmer, more unstable air from northern MS across middle TN and perhaps southern KY and northwest AL. A strong tornado cannot be ruled out, with effective SRH potentially to 500 m2/s2. Severe wind gusts, along with a lesser tornado threat, will exist with storms along the trailing cold front across the remainder of MS and AL. ...MAXIMUM RISK BY HAZARD... Tornado: 10% SIG - Enhanced Wind: 30% SIG - Enhanced Hail: 5% - Marginal

Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sun Nov 04 2018 Valid 051200Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER MISSISSIPPI VALLEY INTO A PORTION OF THE TENNESSEE VALLEY... ...SUMMARY... Numerous severe storms with potential for damaging wind and tornadoes are expected Monday evening into the overnight from a portion of the lower Mississippi Valley into the Tennessee and Ohio Valleys. ...Lower Mississippi into the Tennessee and Ohio Valleys... Only minor adjustments have been made to previous outlook, and guidance remains generally consistent. Potential still exists for significant severe weather to transpire Monday evening and night, mainly from the lower MS Valley into the Tennessee Valley regions. Primary zone of cyclogenesis should commence Monday evening over the lower MS Valley (northern AR or southern MO) in response to forcing for ascent in exit region of a progressive, intense upper jet streak located within base of an amplifying shortwave trough. The cyclone will deepen as it lifts northeast into the OH Valley Monday night with trailing cold front advancing through the TN and lower MS valley regions. Latest observations indicate surface winds over the western Gulf have shifted to southerly, and this air continues to modify with dewpoints already in the low 60s F. Cold front now moving through east TX as of early Sunday morning will stall along the Gulf coast, allowing the Gulf boundary layer to modify further through Monday. Gulf moisture with mid to upper 60s F dewpoints will advect rapidly northward through the warm sector along a strengthening low level jet, contributing to destabilization with 500-1500 J/kg MLCAPE by Monday night, but mid level lapse rates will remain somewhat marginal. Mixed storm modes including a squall line and supercells are likely to develop along and just ahead of advancing cold front by late Monday afternoon, initially over the lower MS Valley, then continuing east into the TN and OH Valleys overnight. Impressive wind profiles with large 0-1 km hodographs and intense mid-upper jet should foster organized storms including embedded bowing segments and supercells with low-level mesocyclones capable of mainly damaging wind and tornadoes, though some hail will also be possible. A moderate risk upgrade might be warranted for a portion of this region in later outlooks. ...MAXIMUM RISK BY HAZARD... Tornado: 10% SIG - Enhanced Wind: 30% SIG - Enhanced Hail: 15% - Slight

The dry layer in the mid levels will pump the instability in the Mid Valley,if it's right of course.Hard to go against the Euro this time frames.Really still think the hatched area will go east next run and possible more north

The Euro on tonights run shows the winds in the Mid Valley down to 60kts at 1kmb on the skew-t in middle Tn,would be winds around 70mph if its right and mixes down,sounding are BNA And it also shows some drier air in the mid levels

Yeah, even when convection becomes more linear, there could easily be rotation and spinups within the severe line through dawn and mid morning. Yeah,we haven't seen this set-up in years in the Valley with fall severe.With the linear you mention both the GFS AND Euro shows winds of 50kts down to 1kMB in our area,so a good chance we could see winds around 60 mph here possibly even more with convection.But this looks more wind and possible tornado,not alot of dry air in the mid levels,otherwise this would be a potential loaded gun

The wind profiles on the Euro are really impressive into the Mid Valley into the lower OV before the system heads away.There still looks to be a tornado chance for the whole Valley until you might get to the TN/NC mountains

If the SPC goes by the GFS and Euro the hatched area should get expanded more into Mid Tn and Western Ky

Area Forecast Discussion National Weather Service Nashville TN 251 PM CDT Sat Nov 3 2018 .DISCUSSION... Our main concern continues to be severe thunderstorm potential. Models are continuing to come together, focusing on Monday night for a line of thunderstorms to cross Middle Tennessee. This line of storms will likely produce some wind damage, and may contain a few spinup tornadoes. But first in the short term, we will have clear to partly cloudy skies tonight with lows in the 40s. On Sunday, a low pressure system will lift across the midwest with a trough trailing down across Tn. This system will create gusty winds on Sunday with gusts over 30 mph at times. A few limbs could come down with a couple of midday gusts around 40 mph. Showers will develop from west to east Sunday afternoon and early evening. Showers will be mainly light with most locations having under one tenth of an inch of rainfall. We should start out Monday with only small chances for showers. A potent low pressure system will be working out of the Rockies on Monday. A trough will take on a negative orientation by Monday night with a surface low deepening as it lifts northeastward out of the Mid Mississippi Valley, and a trailing cold front that will sweep eastward. There is no doubt this system will have more than ample shear to work with as models show deep layer shear over 45KT, including favorable low level shear for spinup tornadoes along the expected squall line. Models are showing a tongue of 500-1000 cape ahead of the cold front which should be adequate to develop severe thunderstorms. Models are in good agreement with storms coming into our west after 9 PM Monday evening and moving off to our east before 8 AM Tuesday. SPC shows the western two thirds in an enhanced risk for Monday night and the rest of the area in a slight risk. With the bulk of the showers and thunderstorms moving off early Tuesday morning, election day should be pretty much rain-free, partly cloudy, and breezy. Cooler and drier air will come in for Tuesday night and Wednesday.

The hatched area today

The Euro is more severe than the GFS into the Western Valley into the late afternoon,early evening,with possible discrete storms ahead.The showalter even would suggest this with drier air into the mid levels for thunderstorms.Wind profiles no need to mention,they would be there by both GFS and Euro.The hatched area from the SPC still looks good to me via the Euro,but it could get expanded more into SW Kentucky,by this afternoons runs,but can surely change the next runs.

Thank you

Odd,he removed it

Tropical/Northern Hemisphere

Seen some good predictions for "AN" snowfall.Hope it happens.Still like yalls area better,i like Dave's maps, -NAO will keep storms suppressed to the South and east,unless it's a really strong system we generally are left out.

MUCapes even look better this afternoon on the GFS,over 1k west of Nashville.But all in all you never want to see a over night severe threat while people sleep.Soundings show a possible tornado threat for the vast part of the Valley,right now anyways.

Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0233 AM CDT Sat Nov 03 2018 Valid 051200Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY... ...SUMMARY... Numerous severe storms with potential for damaging wind and tornadoes are expected Monday evening into the overnight from a portion of the lower Mississippi Valley into the Tennessee and Ohio Valleys. Primary change to previous outlook for Monday has been to expand the severe risk areas farther north and east based on latest trends in model guidance. Potential still exists for significant severe weather to transpire Monday evening and overnight, mainly from the lower MS Valley into the Tennessee Valley regions. Though the NAM and GFS are slightly less amplified with approaching upper trough compared to the ECMWF, models have demonstrated reasonably good consistency. Cyclogenesis should commence by Monday evening over the lower MS Valley in response to ascent within exit region of an approaching, intense jet streak within base of an amplifying shortwave trough. The low is forecast to deepen as it lifts northeast into the OH Valley overnight with trailing cold front advancing through the TN and lower MS valley regions. Richer low-level moisture residing over the northern Gulf will advect rapidly northward through the warm sector in response to the strengthening low-level jet, contributing to destabilization with modest instability (1000-1500 J/kg MLCAPE). Mixed storm modes including a squall line and supercells are likely to develop along and ahead of advancing cold front Monday afternoon initially over the lower MS Valley, and continuing east into the TN Valley and Southeast States Monday night. Impressive wind profiles with large hodographs and an intense upper jet will promote a threat for mainly damaging wind and tornadoes, though some hail will also be possible.

I wasn't going to do this after this afternoon run on the GFS, but the GFS looks better this evening.Negative tilted trough and there also a possibility of some discrete storms in the afternoon in the Western Valley Monday afternoon.But the main threat looks to be towards late evening/early morning hours.

Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0407 AM CDT Fri Nov 02 2018 Valid 051200Z - 101200Z ...DISCUSSION... Potential exists for a significant severe event to transpire day 4 (Monday) into day 5 (Tuesday) mainly from the lower MS Valley into the Southeast States. Model solutions have converged and demonstrated run to run consistency, depicting significant cyclogenesis to commence by Monday evening over the lower MS Valley in response to an approaching intense upper jet within base of an amplifying shortwave trough. The low is forecast to deepen as it lifts northeast into IL overnight with trailing cold front advancing through the TN and lower MS valley regions. Richer low-level moisture residing over the northern Gulf will advect rapidly northward through the warm sector in response to the strengthening low-level jet, contributing to destabilization with moderate instability possible from east TX into a portion of the Gulf Coast states. Severe storms are likely to develop along advancing cold front Monday afternoon initially from southeast OK into east TX, then spreading into the lower MS Valley and TN Valley regions Monday night. Impressive wind profiles with large hodographs and an intense upper jet will promote a threat for damaging wind, tornadoes and large hail. Severe threat will continue east through portions of the Southeast states and Middle Atlantic Tuesday.