• UTC: 2018-12-11 18:49

tornado/severe thunderstorm watches

  • SPC - No watches are valid as of Tue Dec 11 18:02:02 UTC 2018
    on December 11, 2018 at 6:01 pm

    No watches are valid as of Tue Dec 11 18:02:02 UTC 2018. […]

  • SPC - No MDs are in effect as of Tue Dec 11 18:02:02 UTC 2018
    on December 11, 2018 at 6:01 pm

    No Mesoscale Discussions are in effect as of Tue Dec 11 18:02:02 UTC 2018. […]

  • SPC Dec 11, 2018 1730 UTC Day 2 Convective Outlook
    on December 11, 2018 at 5:33 pm

    SPC 1730Z Day 2 Outlook Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CST Tue Dec 11 2018 Valid 121200Z - 131200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected to develop across a portion of southeast and east Texas into the lower Mississippi Valley Wednesday night. However, the risk for severe weather still appears low at this time. ...Eastern Texas through western LA... A shortwave trough currently over southern CA will accelerate eastward in response to an upstream impulse, reaching central and southern TX late Wednesday night. The surface cyclone that will develop in response to this feature is forecast to be located over north central TX with a Pacific cold front extending southward to near Del Rio by the end of this period. As of mid day Tuesday, northeast trajectories are maintaining the advection of modified continental polar air across the western Gulf with near surface dewpoints mostly in the 40s F. Surface winds will veer to southerly over the western Gulf and eastern TX early Wednesday as high pressure over the southeast U.S. moves farther east. This will result in northward advection of modifying continental polar air with dewpoints reaching the low 50s F over northeast TX to low 60 F along the TX coast tomorrow night. A corridor of weak instability (MUCAPE at or below 500 J/kg) should evolve from the TX coastal area through east central TX overnight. Storms are expected to develop along evolving warm conveyor belt and zone of deepening ascent from southeast through east TX as the shortwave trough approaches Wednesday night. Vertical wind profiles including size of low-level hodographs will increase within this zone, but current indications are that moisture return will probably be insufficient for complete removal of the near-surface stable layer, and storms will remain slightly elevated which, along with the very marginal thermodynamic environment, should limit overall severe threat. For this reason will not introduce any severe probabilities at this time, but at least a marginal risk category might be needed in day 1 updates. ...MAXIMUM RISK BY HAZARD... Tornado: Read mor […]

  • SPC Day 2 Fire Weather Outlook
    on December 11, 2018 at 4:19 pm

    SPC Day 2 Fire Weather Outlook Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1018 AM CST Tue Dec 11 2018 Valid 121200Z - 131200Z After fuels collaboration with the local offices, it was decided that fuel conditions and weather conditions warrant an elevated fire weather area in eastern New Mexico and the far western Texas panhandle Wednesday afternoon. Winds are expected to be around 20 mph with RH values falling to around 20%. ..Bentley.. 12/11/2018 .PREV DISCUSSION... /ISSUED 0114 AM CST Tue Dec 11 2018/ ...Synopsis... A vigorous mid-level system will amplify southeastward from the Pacific Northwest toward the southern High Plains, while closing off late in the forecast period. This system will result in another episode of strong cyclogenesis in northeastern New Mexico and vicinity, with resultant strengthening of downslope flow and locally elevated fire weather across eastern New Mexico. Meanwhile, gusty winds in southern California will take on more of an onshore component, with limited low-level drying resulting in only a locally elevated fire weather threat. ...Eastern New Mexico... Areas of 25-35 mph westerly surface flow will develop during peak heating hours in response to aforementioned cyclogenesis. Meanwhile, some low-level drying is expected, with RH values falling into the 18-35% range during the afternoon. While typically these conditions would justify an elevated fire weather delineation, fuels appear to be driest just north of this region and ERCs are not particularly high. Thus, locally elevated fire weather conditions are expected, and elevated delineations may be needed in later outlooks. ...Please see www.spc.noaa.gov/fire for graphic product... Read mor […]

  • SPC Dec 11, 2018 1630 UTC Day 1 Convective Outlook
    on December 11, 2018 at 4:13 pm

    SPC 1630Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1008 AM CST Tue Dec 11 2018 Valid 111630Z - 121200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible late this evening through tonight along the Pacific Northwest coast. ...Synopsis... Relatively cool/dry air in the low levels will dominate the majority of the CONUS, with no threat for thunderstorms. A southern stream shortwave trough will move over northern Baja through tonight, though any substantial low-midlevel moistening and related threat for deep convection will remain south of the AZ border. A northern stream shortwave trough over the southeast Gulf of AK will progress inland over WA/northern OR this evening into tonight. Steep low-midlevel lapse rates with the midlevel thermal trough, in the post-frontal onshore flow regime, will support weak surface-based buoyancy (SBCAPE generally 100-300 J/kg) and an attendant threat for isolated, low-topped thunderstorms late this evening into tonight. ..Thompson.. 12/11/2018 Read mor […]

  • SPC Day 1 Fire Weather Outlook
    on December 11, 2018 at 3:39 pm

    SPC Day 1 Fire Weather Outlook Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0937 AM CST Tue Dec 11 2018 Valid 111700Z - 121200Z ...NO CRITICAL AREAS... No changes. See previous discussion below for additional details. ..Bentley.. 12/11/2018 .PREV DISCUSSION... /ISSUED 0112 AM CST Tue Dec 11 2018/ ...Synopsis... An active synoptic pattern will continue across the Lower 48 today, with stout mid-level disturbances centered over the northern/central Great Plains, Northeast, southern California, and the Pacific Northwest. The Great Plains wave will induce cyclogenesis in northeastern New Mexico and vicinity, while Great Basin high pressure will assist in development of an offshore pressure gradient across southern California. Although highlights have been withheld for this outlook, areas of locally elevated fire weather conditions will develop at times across the central Plains and along coastal ranges of southern California. ...Northeastern New Mexico northeastward into western Kansas... 10-15 mph westerly downslope flow will develop in vicinity of the deepening surface low and west of a front/wind shift from the Panhandles into central Kansas. Minimum RH values will fall to around 20-35% west of the wind shift, and fuels are not expected to support large fires on a widespread basis. Nevertheless, where finer fuels are cured, locally elevated fire weather will develop for a couple of hours during peak heating. ...Southern California... Gusty offshore flow will develop throughout the day in response to the aforementioned pressure gradient. Minimum RH values should only fall to around 20-30% however, and fuels are not cured on a widespread basis owing to recent rainfall across the area. Locally elevated fire weather conditions can be expected where fine fuels are dry. ...Please see www.spc.noaa.gov/fire for graphic product... Read mor […]

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