SPC Dec 3, 2022 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1140 PM CST Fri Dec 02 2022 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...Synopsis... A leading shortwave trough will move quickly across the Great lakes and Northeast, within a larger-scale area of cyclonic flow aloft around a Hudson Bay low. Primarily westerly flow aloft will exist over the remainder of the CONUS, except for the coastal Pacific Northwest where an upper low will be just offshore. Here, a few lightning flashes with limited coverage will be possible off the coast. A cold front will be positioned roughly from eastern TX to the OH Valley Saturday morning, and will quickly push eastward with high pressure behind. Scattered showers will likely occur in association with this fast-moving front, but instability will be quite limited for thunderstorms. However, sufficient elevated instability will exist during the day for sporadic lighting flashes over the northern Gulf Coast and perhaps toward the Mid Atlantic early in the day, with little large-scale support. ..Jewell/Moore.. 12/03/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC Dec 2, 2022 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1122 PM CST Thu Dec 01 2022 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today through tonight. ...Synopsis... Broad ridging is noted across the central and eastern CONUS in water vapor imagery ahead of a progressive upper wave, currently passing through the Great Basin. The strong flow regime over the central/northern Rockies is yielding robust lee troughing with a surface cyclone evident in surface observations over the western Dakotas. This surface low will shift east through the day into the upper MS River Valley with an attendant cold front sweeping southeastward across the Plains into the lower MS Valley by early Saturday. Modest low-level moisture return within a warm advection regime ahead of the cold front will support adequate buoyancy and lift for elevated thunderstorms from the lower MS Valley to the upper OH Valley late this afternoon and into the overnight hours. Strong effective shear may support transient organization of any stronger updrafts, but weak/shallow CAPE profiles will modulate updraft intensities and limit the overall severe threat. ..Moore/Hart.. 12/02/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC Nov 30, 2022 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CST Tue Nov 29 2022 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PANHANDLE...SOUTHEASTERN ALABAMA...AND SOUTHERN/CENTRAL GEORGIA... ...SUMMARY... Thunderstorms capable of producing scattered damaging winds and a tornado or two will be possible across parts of the Southeast, mainly this morning. ...Southeast... A line of strong to severe thunderstorms will likely be ongoing at the start of the period later this morning from near the mouth of the MS River northeastward into GA. This line is expected to continue moving quickly southeastward across southern AL, the FL Panhandle, and central/southern GA through midday. A sufficiently moist and unstable airmass should be in place ahead of the line across these areas, with weaker instability with northward extent into GA. Given the linear convective mode, scattered damaging winds should be the primary severe threat this morning. Low-level flow is forecast to gradually veer and weaken with time as a southerly low-level jet shifts northward and away from the surface warm sector. This should result in slowly weakening low-level shear through the morning. Still, a tornado or two embedded within the line may occur before the low-level flow veers/weakens too much. Convection should diminish in coverage and intensity through the afternoon across southeast GA and north FL as it encounters a less unstable airmass and becomes displaced from the stronger forcing aloft. ...Mid-Atlantic/New England... A pronounced mid/upper-level trough initially over the Great Lakes and OH Valley will move east-northeastward over the Mid-Atlantic and New England by this evening. A strong cold front will develop eastward across the Mid-Atlantic and Northeast through the day, with rather meager low-level moisture return expected along/ahead of the front. Still, the gradually increasing moisture, favorable low-level convergence along the front, and strong large-scale ascent may support the development of a low-topped frontal band within the larger precipitation shield. Strong wind gusts could accompany any such convective band. But, with surface-based instability forecast to remain negligible, the potential for convectively enhanced gusts appears too limited to include severe wind probabilities at this time. ..Gleason/Squitieri.. 11/30/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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SPC Nov 29, 2022 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1109 PM CST Mon Nov 28 2022 Valid 291200Z - 301200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS FAR EAST-CENTRAL LOUISIANA INTO CENTRAL MISSISSIPPI... ...SUMMARY... Severe thunderstorms capable of producing tornadoes, very large hail, and a few severe wind gusts are expected this afternoon into the overnight period across parts of the lower to mid Mississippi Valley and parts of the Southeast. A few strong tornadoes will be possible. ...Synopsis... A surface low will deepen while tracking from Kansas to the Great Lakes today, accompanied by an eastward advancing upper trough. A strong mid-level jet stream will overspread an intense low-level jet across the OH/TN Valleys into the Southeast. As such, strong deep-layer flow and shear will overlap with a moistening, destabilizing airmass from late morning to early evening from the lower MS Valley east-northeastward. Several strong to intense thunderstorms are expected to organize and promote a relatively robust severe threat, particularly across the Southeast, where regionally higher instability should reside. ...Portions of the Lower MS Valley today into early tonight... Strong warm-air advection should be underway across the Lower MS Valley at the start of the period (12Z), with rich boundary-layer moisture being transported northward by a 40-50 kt southwesterly low-level jet. Through the day, at least modest surface heating should support surface temperatures rising into the lower 70s F amid upper 60s F dewpoints within the warm-air advection regime, where an increase in thunderstorms is also expected. 50-70 kts of west-southwesterly 500 mb flow and 6.5+ C/km lapse rates will overspread the lower MS Valley and the warm-air advection regime by early afternoon, contributing up to 1500 J/kg MLCAPE, which is adequate in supporting a severe threat. Storms should eventually root into a gradually deepening boundary layer during the afternoon, taking advantage of the strong deep-layer and low-level speed/directional shear provided by the overlapping southwesterly low-level and westerly mid-level jets. Large, curved low-level hodographs with mid/upper-level elongation will support well over 50 kts of effective bulk shear, and 300-400 m2/s2 effective SRH. Supercell structures are expected initially, with large hail, tornadoes, and a few severe gusts all likely. A few instances of 2+ inch diameter hail and/or strong tornadoes are possible with the more robust supercells. Should a more dominant supercell develop, remain discrete, and traverse an axis of locally stronger surface heating/buoyancy, a long-tracked and intense tornado may occur. The latest high-resolution guidance consensus suggests this scenario would be most likely across central MS, where a Category 4/Moderate risk is in place. Later at night, storms should grow upscale into more linear segments as the surface cold front and greater low-level convergence approaches. Damaging gusts should then become the main threat, though a few tornadoes remain possible. ...Parts of the OH/TN Valley into early evening... A strong surface cold front should sweep across the OH/TN Valleys through the late afternoon and evening hours as the deepening surface low tracks across the Great Lakes. Strong convergence along the cold front should force a low-topped band of convection. Ambient tropospheric wind fields will be strong, with 55+ kts of flow likely just 1 km AGL. Downward momentum transport within this line may foster strong, occasionally damaging gusts, with a couple of severe gusts also possible, warranting the introduction of Category 1/Marginal probabilities this outlook. ..Squitieri/Darrow.. 11/29/2022 Read more CHECK UPDATE ZOOM GRAPHIC
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