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yoda

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Everything posted by yoda

  1. The mix line is because of a slight warm intrusion at around 800mb. EZF is upper 20s surface at the time
  2. 800mb gets to 0c on the soundings... surface is fine for all
  3. Low is stronger at 00z 117 compared to 18z 111 in Oklahoma
  4. 2-4 for most of VA into DC... 1-2 for most of MD... 1" for NE MD on 12z CMC
  5. Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 AM CST Tue Dec 31 2024 Valid 311300Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL APPALACHIANS TO PARTS OF THE MID-ATLANTIC... ...SUMMARY... Damaging to isolated marginally severe gusts, isolated large hail, and possibly a brief tornado, are possible today from the central Appalachians to parts of the Mid-Atlantic. ...Synopsis... In mid/upper levels, a progressive shortwave pattern will persist within a broadly cyclonic flow field covering much of the CONUS from the Rockies eastward. The most important of these features for convective potential will be a well-developed shortwave trough -- evident in moisture-channel imagery from a low over IL south- southeastward to western portions of KY and the lower Tennessee Valley region. Though the 500-mb low may not remain closed, the trough will remain strong and shift east-northeastward up the Ohio Valley today, reaching OH, WV and the western Appalachians of VA/NC by 00Z. The trough should pivot over the northern Mid-Atlantic and offshore from the Delmarva Peninsula by 12Z. At the surface, 11Z analysis showed a low between CMI-MTO, related to the shortwave trough aloft, a cold front arching southwestward across western parts of TN/KY, and a warm front east-southeastward across northeastern KY that will shift northeastward over portions of WV and southern OH through the early afternoon, as the low occludes and moves northeastward. By 00Z, the low should reach the CLE area, with cold front moving eastward across western parts of VA and NC, and warm front moving north up the Atlantic Coast and across the Delmarva Peninsula. An older frontal zone, now well offshore, should continue to weaken, with considerable theta-e advection occurring to its west near the coast. ...Central Appalachians to Mid-Atlantic... Episodic lines and clusters of thunderstorms are expected to move eastward across the outlook area today, from the northern Cumberland/southern Allegheny Plateau region eastward toward coastal Delmarva and vicinity, with occasional strong/isolated severe gusts and hail the main severe modes, but with marginal tornado threat as well. Large-scale ascent will spread over this region in the form of strong midlevel DCVA/cooling immediately preceding the trough, as well as the peripheral/ageostrophic influences of the left exit region of a strong 250-300-mb jet, centered from the Ozarks to the western Carolinas. Associated destabilization aloft will offset modest (but diurnally steepening) low-level lapse rates and marginal moisture behind the offshore front. This yields an area of 100-300 J/kg MLCAPE already apparent in objective analyses between RAOBs, over southern IN, despite cool surface conditions. This weakly buoyant regime is forecast to expand and strengthen somewhat (300-600 J/kg) as it moves eastward over eastern KY late this morning into midday. Long, somewhat curved low-level hodographs and strong low-level shear are expected, supporting potential for embedded/low-topped supercells, as well as LEWP/bow features with any linear modes. The area of large-scale lift and accompanying strong-severe convective potential then will shift across WV to VA/MD/DC and the Delmarva region, encountering theta-e advection from a modified post-frontal airmass over the Atlantic. This regime then should move offshore, where even more-extensive convective development is likely overnight. The wind and tornado areas have been shifted south out of most of PA, where the low-level stable/inversion layer should hold, and expanded westward into portions of eastern KY, where surface-based buoyancy will exist as the cold-core region moves overhead. Severe potential probably will be discontinuous across this corridor, and a lack of more-robust buoyancy precludes more than a marginal unconditional severe threat for this outlook cycle. ------------------ ...Epilogue (RE)... This is my final SPC outlook, forecast and shift. With a cyclonically swirling storm of memories, I retire mourning the end of a rewarding era, yet ever grateful, blessed with a career of public service devoted to excellence. For a poor kid from inner-city east Dallas, carrying a passion for tornadoes from earliest awareness, and a relentless drive to research and forecast them, it has been everything the dream promised, and more. I hope the American taxpayers have found my time worth their money. Even through this autumnal transition of life's seasons, I'll stay as inspired as ever by the tempestuous sky above -- to observe, photograph and study it, and keep giving back to the science in some way, as long as physically and mentally able. It just won't be on rotating shifts. The forecasting baton passes to another generation of sharp minds, just as the lead crew in the 1990s did for us "young pups of SELS" in Kansas City. The SPC is in great hands. There isn't enough room here to thank everyone from early childhood through OU, NSSL, NHC, NSSFC/SELS, and SPC -- family, friends, instructors, mentors, students, and colleagues -- but be assured I do. Nothing has granted greater career fulfillment than to deliver severe-weather forecasts with detailed, science-based insights, customized for each situation, shift after shift for over three decades, and to write related research papers. Thanks for reading and using them, any or all. Stay weather-aware! ..Edwards/Grams.. 12/31/2024
  6. Apparently the 1300z SPC OTLK was Edwards last day
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