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SPC Jan 7, 2024 1730 UTC Day 2 Convective Outlook

1 year 6 months ago

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1136 AM CST Sun Jan 07 2024 Valid 081200Z - 091200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL GULF COAST OVERNIGHT MONDAY INTO EARLY TUESDAY... ...SUMMARY... Severe thunderstorms capable of strong wind gusts and tornadoes are expected from southeast Texas across the central Gulf Coast and from Monday afternoon into early Tuesday morning. Greatest severe potential is anticipated overnight from southeast Louisiana across southern Mississippi and southern Alabama, and into the western Florida Panhandle. ...Synopsis... Shortwave trough currently extending from Great Basin through the northern Baja Peninsula is forecast to move eastward today while intensifying. By 12Z Monday morning this shortwave will likely have matured into a mid-latitude cyclone centered over northeast NM, with an extensive belt of strong mid-level flow throughout its southern periphery. This cyclone is then expected to evolve eastward across the TX Panhandle and OK throughout the day, with mid-level flow strengthening considerably throughout its eastern periphery. By Monday evening, 100+ kt at 500-mb will likely stretch from the Edwards Plateau into the Ozark Plateau. Further strengthening of this mid-level flow is anticipated overnight Monday as the cyclone tracks a bit more northeastward, ending the period over western MO. Intense low-level flow will accompany this cyclone as well, with a large area of 50+ kt over the southern Plains early Monday. This low-level jet will shift eastward throughout the day and overnight, while gradually strengthening. By early Tuesday morning, 60+ kt 850-mb flow will cover much of the Southeast, with 70+ kt possible from northern MS into middle TN and northern AL. Previous frontal intrusion (evidenced by the cold and dry conditions over the southern Plains and Southeast Sunday) will limit the northern extent of the moisture return and associated severe-thunderstorm potential. General expectation is for secondary surface cyclogenesis over central TX Monday morning, with the primary low well to the north over the TX/OK Panhandles. This secondary low (and associated warm front) should delineate the northern extent of the severe potential as it gradually moves eastward across central portions of east TX and into central LA Monday afternoon and evening. This low is forecast to continue eastward overnight Monday into early Tuesday, progressing across central MS and AL. Severe thunderstorms are expected within the warm sector ahead of this low, as well as along the associated cold front as it surges eastward. ...North TX Early Monday... As the strong mid-level flow associated with the cyclone moves into southern Plains, a fast-moving line of showers and embedded thunderstorms is expected to move across north TX early Monday morning. Forecast soundings show very weak thermodynamics, limiting overall updraft strength and duration. However, given the strong low and upper level support, a narrow-line of forced convection may become capable of locally gusty/damaging wind gusts as it moves eastward. ...TX Coastal Plain/Southeast TX into southwest LA Monday Afternoon and Evening... Two rounds of strong to severe thunderstorms are possible across the region Monday, with the first round likely beginning early Monday afternoon as the warm sector moves into the region. Current guidance suggests this warm sector will be characterized by temperatures in the low 70s, dewpoints in the upper 60s, and moderate buoyancy. However, given the prevalence of cloud cover and early period showers, there is uncertainty regarding if temperatures can reach the low 70s. If they do, some surface-based supercells capable of all severe hazards, including tornadoes are possible. If temperatures stay in the 60s, low-level stability would likely inhibit surface-based storm development, mitigating the severe potential. Consensus within the guidance has trended towards warmer temperatures and tornado probabilities were increased across the region as a result. A further increase in probabilities may be needed in later outlooks if confidence in surface-based storms increases. Additional thunderstorm development is anticipated along the front as it moves through, but the strength of these storms will be predicated on coverage and strength of any warm sector development. Strong wind gusts would be the primary severe risk with this convective line. ...Central Gulf Coast Overnight Monday into Tuesday Morning... As the surface low continues eastward, a convective line is expected to mature along the cold front as it encounters a moderately moist and buoyant airmass and increasingly strong low-level flow. As the line matures, it will likely transition from a more parallel stratiform structure to a more organized leading-line, trailing stratiform configuration. Robust low-level kinematics, characterized by 50-60 kt just above the surface and 500+ m2/s2 of 0-3 km SRH, suggest both significant-severe gusts and strong QLCS tornadoes are possible. ..Mosier.. 01/07/2024 Read more