Tag: 4-8

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0330 AM CDT Thu Apr 17 2025 Valid 201200Z - 251200Z ...DISCUSSION... ...Day 4/Sun - ArkLaTex to the Mid-MS Valley... A compact upper shortwave trough is forecast to move from the southern High Plains to the Midwest on Sunday. While some forecast uncertainty continues with regard to exact position of this feature, the overall pattern suggests isolated to scattered severe thunderstorm potential will exist across portions of east TX into the Mid/Lower MS Valley. Strong southwesterly flow aloft will overspread a moist warm sector as a surface

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Wed Apr 16 2025 Valid 191200Z - 241200Z ...DISCUSSION... Severe potential remains apparent into the weekend, but predictability wanes substantially by D5/Sunday. ...D4/Saturday... The persistent longwave trough is expected to breakdown as an embedded northern-stream shortwave impulse accelerates east across ON/QC and the basal shortwave impulse moves more gradually east into the southern High Plains. Through Saturday afternoon, an expansive swath of strong mid-level flow will persist from the central Appalachians southwestward into the southern Great Plains. The nearly stalled baroclinic zone from TX/OK

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Apr 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... An active severe weather pattern expected through at least this weekend, before predictability diminishes early next week. ...D4/Friday... Guidance remains consistent with a broad swath of strong mid-level southwesterlies from the southern High Plains to the Great Lakes, downstream of a longwave trough from northern ON to the Lower CO Valley. This will overlap a similarly oriented surface front. In response to increasing mid-level height falls, a surface cyclone should track across the central Great

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0350 AM CDT Mon Apr 14 2025 Valid 171200Z - 221200Z ...DISCUSSION... Active severe weather pattern expected late week into the weekend. ...D4/Thursday... A longwave trough should become clearly anchored over the West and consist of multiple embedded shortwave impulses. Peak surface cyclone amplitude is largely progged over western KS on Thursday afternoon, with a dryline arcing across eastern KS into the southern Great Plains. Another day of modifying moisture return northward from the western Gulf should yield at least moderate buoyancy ahead of the dryline. A

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Sun Apr 13 2025 Valid 161200Z - 211200Z ...DISCUSSION... An active severe weather pattern is expected late week into next weekend. ...D5/Thursday... Guidance has converged to a signal of severe-storm threat centered on Thursday evening as a deep surface cyclone becomes established in the KS vicinity, downstream of a longwave trough in the West. An enriching low-level moisture plume will be advected nearly due north from the western Gulf towards the Lower MO Valley. A stout EML should limit convective development along much of

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CDT Sat Apr 12 2025 Valid 151200Z - 201200Z ...DISCUSSION... After a relative lull in severe potential mid-week, latest guidance indicates increasing severe possibilities late week. Compared to 24 hours ago, deterministic models have vastly changed to an evolution of a shortwave trough digging south from the Canadian Rockies into the Lower CO Valley during D5-7/Wednesday-Friday. This would support a greater breadth and quality of western Gulf moisture advection across the central states beneath an initially pronounced EML. SPC and NSSL GEFS-based ML guidance indicate

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0330 AM CDT Fri Apr 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... ...D4/Monday... Further amplification of a broadening mid/upper-level trough and attendant surface cyclone is expected across the Upper Great Lakes to the southern ON/QC border area. Poleward moisture quality from the western Gulf will remain sub-optimal, but will continue to improve beneath a lobe of the southern Great Plains EML. The northeast extent of weak surface buoyancy should overspread the OH Valley by Monday afternoon. This portion of the front will coincide with robust 700-500 mb

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0333 AM CDT Thu Apr 10 2025 Valid 131200Z - 181200Z ...DISCUSSION... Primary feature of interest will be a shortwave trough over MT at 12Z Sunday and its major amplification into a broad eastern CONUS/southeast Canadian trough through mid-week. Poleward moisture quality from the western Gulf will remain sub-optimal, but will improve through D5/Monday. The northeast extent of weak surface buoyancy should reach the OH Valley by Monday afternoon, where guidance has been trending farther south with an intense mid-level jet. Given a prior EML and the

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0337 AM CDT Wed Apr 09 2025 Valid 121200Z - 171200Z ...DISCUSSION... From Day 5/Sunday through Day 6/Monday, a robust midlevel trough will advance eastward from the northern Plains to the Great Lakes. On Day 5/Sunday, a related broad/elongated surface low will move eastward across the northern/central Plains, while a dryline develops farther south over the southern Plains. Isolated strong storms may be possible ahead of the surface low in the Upper MS Valley, though poor boundary-layer moisture will tend to limit the severe risk. Farther south

Day 4-8 Outlook Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0337 AM CDT Tue Apr 08 2025 Valid 111200Z - 161200Z ...DISCUSSION... On Day 4/Friday, an amplified large-scale trough will move slowly eastward across the Appalachians. Ahead of a related surface low in the lee of the Appalachians, weakly modified boundary-layer moisture will be in place across the coastal Mid-Atlantic states. While instability will be marginal, owing to the limited moisture and poor lapse rates, strong south-southwesterly midlevel flow may support a couple strong storms during the afternoon. The overall severe threat appears too marginal for severe