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MD 2263 CONCERNING HEAVY SNOW FOR COASTAL LAKE ONTARIO IN WESTERN NEW YORK
Mesoscale Discussion 2263 NWS Storm Prediction Center Norman OK 1121 AM CST Thu Dec 12 2024 Areas affected...coastal Lake Ontario in western New York Concerning...Heavy snow Valid 121721Z - 122115Z SUMMARY...Heavy snow, with rates approaching 2 inches/hr, may accompany the ongoing snow band across eastern Lake Ontario through the early to mid afternoon hours. DISCUSSION...A lake effect snowband is in progress across the eastern shore of Lake Ontario, with periods of at least moderate snowfall rates noted via surface observations. 17Z mesoanalysis shows deep-layer flow fields oriented roughly parallel to the lake axis, supporting a long fetch of onshore moisture. Continued diurnal heating, however weak, is encouraging 8 C/km boundary-layer lapse rates given cooling aloft, and this may support convective snowfall into the afternoon hours. While mostly 1 inch/hr snowfall rates are likely, a couple instances of 2 inch/hr rates may occur. ..Squitieri.. 12/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BTV...ALY...BUF... LAT...LON 44127627 44247564 44287493 44177465 43927510 43867553 43857581 43887614 43917624 44127627 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central States... A shortwave trough over the central Great Plains will progress east into the Midwest, dampening somewhat late in the period. Its associated weak surface cyclone over eastern KS should undergo cyclolysis by early Sunday as it moves across the Mid-MS Valley. 60s surface dew points should generally be confined to east and south TX through Saturday afternoon. Low-amplitude mid-level ridging should begin to overlap this richer moisture. Convection should largely remain elevated within the downstream low-level warm conveyor. A strong storm or two may be possible in between these two regimes in the Sabine Valley vicinity, but weak mid-level lapse rates and diminishing large-scale ascent should preclude an appreciable severe risk. Overall thunderstorm coverage should diminish Saturday evening/night. ...Pacific Coast States... A shortwave impulse embedded within a broader trough should progress across northern CA through midday, before substantially dampening over the northern Great Basin by Saturday night. Large-scale ascent will be greatest from 12-18Z, including a strong low-level jet which will yield enlarged hodograph curvature into the CA Central Valley. But cool surface temperatures and negligible prospects for surface-based instability should preclude a severe risk. While sporadic lightning flashes may accompany elevated convection within the warm conveyor early, the predominant isolated thunderstorm threat should occur along the coast within a persistent onshore flow regime and steepened lapse rates. The latter will diminish from south to north on Saturday night as the trough moves farther inland. ..Grams.. 12/12/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central States... A shortwave trough over the central Great Plains will progress east into the Midwest, dampening somewhat late in the period. Its associated weak surface cyclone over eastern KS should undergo cyclolysis by early Sunday as it moves across the Mid-MS Valley. 60s surface dew points should generally be confined to east and south TX through Saturday afternoon. Low-amplitude mid-level ridging should begin to overlap this richer moisture. Convection should largely remain elevated within the downstream low-level warm conveyor. A strong storm or two may be possible in between these two regimes in the Sabine Valley vicinity, but weak mid-level lapse rates and diminishing large-scale ascent should preclude an appreciable severe risk. Overall thunderstorm coverage should diminish Saturday evening/night. ...Pacific Coast States... A shortwave impulse embedded within a broader trough should progress across northern CA through midday, before substantially dampening over the northern Great Basin by Saturday night. Large-scale ascent will be greatest from 12-18Z, including a strong low-level jet which will yield enlarged hodograph curvature into the CA Central Valley. But cool surface temperatures and negligible prospects for surface-based instability should preclude a severe risk. While sporadic lightning flashes may accompany elevated convection within the warm conveyor early, the predominant isolated thunderstorm threat should occur along the coast within a persistent onshore flow regime and steepened lapse rates. The latter will diminish from south to north on Saturday night as the trough moves farther inland. ..Grams.. 12/12/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central States... A shortwave trough over the central Great Plains will progress east into the Midwest, dampening somewhat late in the period. Its associated weak surface cyclone over eastern KS should undergo cyclolysis by early Sunday as it moves across the Mid-MS Valley. 60s surface dew points should generally be confined to east and south TX through Saturday afternoon. Low-amplitude mid-level ridging should begin to overlap this richer moisture. Convection should largely remain elevated within the downstream low-level warm conveyor. A strong storm or two may be possible in between these two regimes in the Sabine Valley vicinity, but weak mid-level lapse rates and diminishing large-scale ascent should preclude an appreciable severe risk. Overall thunderstorm coverage should diminish Saturday evening/night. ...Pacific Coast States... A shortwave impulse embedded within a broader trough should progress across northern CA through midday, before substantially dampening over the northern Great Basin by Saturday night. Large-scale ascent will be greatest from 12-18Z, including a strong low-level jet which will yield enlarged hodograph curvature into the CA Central Valley. But cool surface temperatures and negligible prospects for surface-based instability should preclude a severe risk. While sporadic lightning flashes may accompany elevated convection within the warm conveyor early, the predominant isolated thunderstorm threat should occur along the coast within a persistent onshore flow regime and steepened lapse rates. The latter will diminish from south to north on Saturday night as the trough moves farther inland. ..Grams.. 12/12/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central States... A shortwave trough over the central Great Plains will progress east into the Midwest, dampening somewhat late in the period. Its associated weak surface cyclone over eastern KS should undergo cyclolysis by early Sunday as it moves across the Mid-MS Valley. 60s surface dew points should generally be confined to east and south TX through Saturday afternoon. Low-amplitude mid-level ridging should begin to overlap this richer moisture. Convection should largely remain elevated within the downstream low-level warm conveyor. A strong storm or two may be possible in between these two regimes in the Sabine Valley vicinity, but weak mid-level lapse rates and diminishing large-scale ascent should preclude an appreciable severe risk. Overall thunderstorm coverage should diminish Saturday evening/night. ...Pacific Coast States... A shortwave impulse embedded within a broader trough should progress across northern CA through midday, before substantially dampening over the northern Great Basin by Saturday night. Large-scale ascent will be greatest from 12-18Z, including a strong low-level jet which will yield enlarged hodograph curvature into the CA Central Valley. But cool surface temperatures and negligible prospects for surface-based instability should preclude a severe risk. While sporadic lightning flashes may accompany elevated convection within the warm conveyor early, the predominant isolated thunderstorm threat should occur along the coast within a persistent onshore flow regime and steepened lapse rates. The latter will diminish from south to north on Saturday night as the trough moves farther inland. ..Grams.. 12/12/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 PM CST Thu Dec 12 2024 Valid 141200Z - 151200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Central States... A shortwave trough over the central Great Plains will progress east into the Midwest, dampening somewhat late in the period. Its associated weak surface cyclone over eastern KS should undergo cyclolysis by early Sunday as it moves across the Mid-MS Valley. 60s surface dew points should generally be confined to east and south TX through Saturday afternoon. Low-amplitude mid-level ridging should begin to overlap this richer moisture. Convection should largely remain elevated within the downstream low-level warm conveyor. A strong storm or two may be possible in between these two regimes in the Sabine Valley vicinity, but weak mid-level lapse rates and diminishing large-scale ascent should preclude an appreciable severe risk. Overall thunderstorm coverage should diminish Saturday evening/night. ...Pacific Coast States... A shortwave impulse embedded within a broader trough should progress across northern CA through midday, before substantially dampening over the northern Great Basin by Saturday night. Large-scale ascent will be greatest from 12-18Z, including a strong low-level jet which will yield enlarged hodograph curvature into the CA Central Valley. But cool surface temperatures and negligible prospects for surface-based instability should preclude a severe risk. While sporadic lightning flashes may accompany elevated convection within the warm conveyor early, the predominant isolated thunderstorm threat should occur along the coast within a persistent onshore flow regime and steepened lapse rates. The latter will diminish from south to north on Saturday night as the trough moves farther inland. ..Grams.. 12/12/2024 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0121 PM CST Thu Dec 12 2024 Valid 122000Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Lightning is possible this evening and tonight along the eastern shores of Lake Ontario in association with lake-effect snow bands. ...20Z Update... The forecast remains on track, and no changes were made with this update. See the previous discussion below for details regarding isolated lightning potential downwind of Lake Ontario. ..Weinman.. 12/12/2024 .PREV DISCUSSION... /ISSUED 1016 AM CST Thu Dec 12 2024/ ...NY... Cool/dry and stable conditions will prevail over the most of the CONUS today, with no organized thunderstorm activity expected. One exception will be in the vicinity of the eastern shores of Lake Ontario (Jefferson/Lewis/Oswego counties). A long-fetch lake-effect snow band is forecast to develop later this evening and tonight. Forecast soundings suggest a sufficiently deep convective layer to promote charge separation and a few lightning strikes - mainly after 02z. Read more

MD 2262 CONCERNING HEAVY SNOW FOR PARTS OF WESTERN NY/EXTREME NORTHWEST PA DOWNSTREAM OF LAKE ERIE
Mesoscale Discussion 2262 NWS Storm Prediction Center Norman OK 0939 AM CST Thu Dec 12 2024 Areas affected...Parts of western NY/extreme northwest PA downstream of Lake Erie Concerning...Heavy snow Valid 121539Z - 121845Z SUMMARY...Very heavy snow rates will continue in the short term, with some weakening possible by early afternoon. DISCUSSION...An intense lake-effect snow band is ongoing this morning across parts of western NY and extreme northwest PA, downstream of Lake Erie. Recent reports suggest snow rates in excess of 3 inches per hour in the heaviest part of the band, with one report of 12 inches over a 2 hour span in Erie County, NY. These very heavy snow rates will persist in some areas through the remainder of the morning. In addition, wind gusts of 30-45 kt have been noted across the region this morning, resulting in occasional blizzard conditions. A notable shortwave trough embedded in deep cyclonic flow is currently moving east of Lake Huron and approaching the lower Great Lakes region. Low-level flow response to this shortwave could result in some disruption of the ongoing snow band by early afternoon, and short-term guidance (including the 12Z CAMs) generally suggest the band will tend to drift south and at least temporarily weaken by early afternoon. ..Dean.. 12/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF...CLE... LAT...LON 42227920 42117968 41998025 42058034 42178032 42278001 42427966 42867843 42907805 42687814 42367878 42227920 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1111 AM CST Thu Dec 12 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through Friday night. ...Central States... A shortwave trough near the Four Corners will move across the southern Rockies into the central Great Plains by early Saturday. The attendant lee surface cyclone will be weak as it tracks from the Raton Mesa vicinity into eastern KS. Modified moisture return from the western Gulf is anticipated within the broad low-level warm conveyor ahead of the minor cyclone. Adequate buoyancy in conjunction with timing of forcing for ascent attendant to the shortwave trough should yield a pronounced increase in elevated convection Friday night into early morning Saturday from the Red River Valley towards the Lower MO Valley. Steeper mid-level lapse rates will be confined to the north side of the mid-level jet in OK to eastern KS. Weak mid-level lapse rates (around 6 C/km) will curtail elevated buoyancy where low-level moisture progressively increases with southern extent. Still, favorable veering of the wind profile with height could yield transient, weak mid-level updraft rotation across parts of east TX to the southern Ozarks. Small hail may occur within the deepest updrafts, with large hail probabilities appearing to be sub-5 percent. ...Northern CA... A pair of shortwave troughs in the northeast Pacific will approach the West Coast. The southern one of these should remain offshore of the northern CA coast through 12Z Saturday. The downstream low-level warm conveyor will yield a swath of rain ahead of a weak cold front. Sufficient low-level moistening, along with some mid-level cooling with the approaching trough, may support scant buoyancy by 09-12Z. Overall thunderstorm probabilities early Saturday morning appear to be around 10 percent near a portion of the northern CA coast. ..Grams.. 12/12/2024 Read more