BBS: TELESC.NET.BR Assunto: DAY48SVR: Nws Storm Prediction Center Norman Ok De: COD Weather Processor Data: Fri, 13 Mar 2026 20:06:26 +0000 ----------------------------------------------------------- ACUS48 KWNS 132006 SWOD48 SPC AC 132004 Day 4-8 Convective Outlook AMEND 1 NWS Storm Prediction Center Norman OK 0304 PM CDT Fri Mar 13 2026 Valid 161200Z - 211200Z AMENDED TO EXPAND D4/MONDAY THREAT AREAS ...DISCUSSION... ...Updated discussion for D4... The majority of deterministic and ensemble model guidance agree on a deep midlevel trough and associated cold front that will move eastward across the Appalachians and to the Atlantic coast by Tuesday morning. Severe storms could be ongoing at the beginning of the period along the northeast Gulf coast into GA. The warm sector, characterized by boundary-layer dewpoints in the 60s, will expand northward (generally east of the Appalachians) through the day as far north as PA. Though clouds could limit downstream surface heating somewhat, very strong wind profiles and focused forcing for ascent will favor a continuation of convection along the front, as well as pre-frontal convection, with the potential to produce relatively widespread damaging winds and several tornadoes. ...Previous discussion below... Significant severe winds and the potential for a few tornadoes will develop on Monday over parts of the Carolinas and Mid Atlantic. Models are in good agreement with the large scale pattern on Monday/D4, depicting a deep upper trough moving out of the Mississippi Valley and ejecting in negative-tilt fashion across the Mid Atlantic and into to the Northeast. Given the antecedent upper ridging on the previous day, low-level southerly winds will help to moisten the air mass well ahead of an approaching cold front. By 12Z Monday, 60s F dewpoints will already extend from northern GA across the Piedmont and into southeast VA, and this plume of moisture will rapidly spread north with near 60 F dewpoints into southeast PA by 00Z. There appears to be two regimes for severe potential on Monday. First, up to 1000 J/kg MUCAPE may develop well ahead of the approaching cold front, and there is some indication that scattered convection may occur across the warm sector from mid to late afternoon. If this occurs, supercells would be most likely, with potential for a few tornadoes from the Carolinas into eastern VA. Models also indicate an elongated pressure fall/rise couplet, which when combined with 50-70 kt 850 mb winds and extreme low-level shear, could easily result in a QLCS along the cold front with corridors of significant damaging winds and embedded tornado risk. Beyond Monday/D4, stable air behind this system will likely preclude any severe threat through Friday/D8. ..Thompson.. 03/13/2026 = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]