Severe Storms

WW 607 SEVERE TSTM CO NE WY 202100Z - 210500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 607 NWS Storm Prediction Center Norman OK 300 PM MDT Tue Aug 20 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Extreme northeast Colorado The western Nebraska Panhandle Southeast Wyoming * Effective this Tuesday afternoon and evening from 300 PM until 1100 PM MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Scattered thunderstorm development is expected late this afternoon/evening from extreme northeast Colorado into southeast Wyoming. The storm environment will favor discrete supercells with isolated very large hail initially, and upscale growth into a cluster is possible late this evening with some damaging wind potential. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 45 miles west northwest of Chadron NE to 65 miles southeast of Cheyenne WY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 604...WW 605...WW 606... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 29010. ...Thompson Read more

MD 1822 CONCERNING SEVERE THUNDERSTORM WATCH 607... FOR PORTIONS OF FAR SOUTHEASTERN WY...FAR NORTHEASTERN CO...AND WESTERN/CENTRAL NE
Mesoscale Discussion 1822 NWS Storm Prediction Center Norman OK 1134 PM CDT Tue Aug 20 2019 Areas affected...Portions of far southeastern WY...far northeastern CO...and western/central NE Concerning...Severe Thunderstorm Watch 607... Valid 210434Z - 210530Z The severe weather threat for Severe Thunderstorm Watch 607 continues. SUMMARY...An isolated hail/wind threat continues across far southeastern WY into the western NE Panhandle. The need for a downstream watch into more of western NE remains unclear. DISCUSSION...Storms across far southeastern WY have recently strengthened and consolidated into a small cluster, which is entering the far western NE Panhandle at 0430Z. In the absence of an obvious large-scale forcing mechanism, this uptick in convective coverage and intensity may be related to a modest strengthening of southerly winds in the 2-3 km layer noted on recent VWPs from KCYS. Regardless, this convection will soon encounter a more buoyant airmass in western NE, where surface dewpoints gradually increase from the low 60s to the low 70s with eastward extent. Some short-term guidance suggests that this ongoing cluster will maintain its intensity, and perhaps even strengthen as it moves eastward overnight across western and eventually central NE. Isolated severe winds and large hail remain the primary concerns. At this point, the need for a new Severe Thunderstorm Watch downstream of WW 607 remains unclear. But, trends will be closely monitored. ..Gleason.. 08/21/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...BOU...CYS... LAT...LON 41580479 42110417 42570329 42520070 41570021 40600039 40550241 40600376 41020474 41580479 Read more

MD 1821 CONCERNING SEVERE THUNDERSTORM WATCH 607... FOR PORTIONS OF SOUTHEASTERN WY...NORTHEASTERN CO...AND THE FAR WESTERN NE PANHANDLE
Mesoscale Discussion 1821 NWS Storm Prediction Center Norman OK 1005 PM CDT Tue Aug 20 2019 Areas affected...Portions of southeastern WY...northeastern CO...and the far western NE Panhandle Concerning...Severe Thunderstorm Watch 607... Valid 210305Z - 210430Z The severe weather threat for Severe Thunderstorm Watch 607 continues. SUMMARY...An isolated severe threat continues across mainly western portions of Severe Thunderstorm Watch 607. DISCUSSION...Storms have generally weakened this evening along and just east of the higher terrain in southeastern WY and northeastern CO. Even with continued low-level easterly upslope flow across this region, convective inhibition has increased. Convective overturning from storms earlier this afternoon/evening may have also locally reduced mid-level lapse rates. Even so, weak to moderate instability coupled with sufficient shear may continue to support an isolated severe threat across mainly western portions of Severe Thunderstorm Watch 607 in the short term. Large hail remains the primary threat. The potential for clustering of storms later tonight into the western NE Panhandle appears lower due to a general lack of storm organization and intensity across southeastern WY as of 03Z. ..Gleason.. 08/21/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BOU...CYS... LAT...LON 42550523 42910456 42920378 40050380 40090466 42000520 42550523 Read more

WW 0607 Status Updates
STATUS REPORT ON WW 607 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..08/21/19 ATTN...WFO...BOU...CYS... STATUS REPORT FOR WS 607 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC087-123-210340- CO . COLORADO COUNTIES INCLUDED ARE MORGAN WELD NEC007-013-033-045-105-123-157-165-210340- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES KIMBALL MORRILL SCOTTS BLUFF SIOUX WYC015-021-027-031-210340- WY . WYOMING COUNTIES INCLUDED ARE GOSHEN LARAMIE NIOBRARA PLATTE Read more

WW 0607 Status Updates
STATUS REPORT ON WW 607 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..08/21/19 ATTN...WFO...BOU...CYS... STATUS REPORT FOR WS 607 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC087-123-210340- CO . COLORADO COUNTIES INCLUDED ARE MORGAN WELD NEC007-013-033-045-105-123-157-165-210340- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES KIMBALL MORRILL SCOTTS BLUFF SIOUX WYC015-021-027-031-210340- WY . WYOMING COUNTIES INCLUDED ARE GOSHEN LARAMIE NIOBRARA PLATTE Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Tue Aug 20 2019 Valid 210100Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTH CENTRAL PLAINS INTO LOWER MISSOURI VALLEY... ...SUMMARY... Storms developing this evening and overnight tonight will pose a risk for severe hail and wind across the north central Plains into lower Missouri Valley. ...01Z Update... Isolated damaging wind gusts remain possible along the outflow boundary extending from northern AR across TN, eastern KY, and into far eastern OH. Vertical shear is weak, leading to transient updrafts along the boundary but ample low-level moisture and strong buoyancy support water-loading and strong wet downbursts. Farther west across central High Plains, thunderstorms ongoing within the moist and steep lapse rate environment continue to pose a risk for large hail and strong wind gusts. A tornado or two also still remains possible. The low-level jet is expected to strengthen tonight across the southern and central Plains, contributing to an increase in thunderstorms across NE. Steep mid-level lapse rates (sampled well by the 00Z LBF sounding) and very moist low-levels will likely result in strong updrafts capable of hail. Some potential exists upscale growth and the development of a deep cold pool, resulting in a forward-propagating MCS. This MCS would pose a threat for strong wind gusts and large hail. ..Mosier.. 08/21/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Tue Aug 20 2019 Valid 210100Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTH CENTRAL PLAINS INTO LOWER MISSOURI VALLEY... ...SUMMARY... Storms developing this evening and overnight tonight will pose a risk for severe hail and wind across the north central Plains into lower Missouri Valley. ...01Z Update... Isolated damaging wind gusts remain possible along the outflow boundary extending from northern AR across TN, eastern KY, and into far eastern OH. Vertical shear is weak, leading to transient updrafts along the boundary but ample low-level moisture and strong buoyancy support water-loading and strong wet downbursts. Farther west across central High Plains, thunderstorms ongoing within the moist and steep lapse rate environment continue to pose a risk for large hail and strong wind gusts. A tornado or two also still remains possible. The low-level jet is expected to strengthen tonight across the southern and central Plains, contributing to an increase in thunderstorms across NE. Steep mid-level lapse rates (sampled well by the 00Z LBF sounding) and very moist low-levels will likely result in strong updrafts capable of hail. Some potential exists upscale growth and the development of a deep cold pool, resulting in a forward-propagating MCS. This MCS would pose a threat for strong wind gusts and large hail. ..Mosier.. 08/21/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Tue Aug 20 2019 Valid 210100Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTH CENTRAL PLAINS INTO LOWER MISSOURI VALLEY... ...SUMMARY... Storms developing this evening and overnight tonight will pose a risk for severe hail and wind across the north central Plains into lower Missouri Valley. ...01Z Update... Isolated damaging wind gusts remain possible along the outflow boundary extending from northern AR across TN, eastern KY, and into far eastern OH. Vertical shear is weak, leading to transient updrafts along the boundary but ample low-level moisture and strong buoyancy support water-loading and strong wet downbursts. Farther west across central High Plains, thunderstorms ongoing within the moist and steep lapse rate environment continue to pose a risk for large hail and strong wind gusts. A tornado or two also still remains possible. The low-level jet is expected to strengthen tonight across the southern and central Plains, contributing to an increase in thunderstorms across NE. Steep mid-level lapse rates (sampled well by the 00Z LBF sounding) and very moist low-levels will likely result in strong updrafts capable of hail. Some potential exists upscale growth and the development of a deep cold pool, resulting in a forward-propagating MCS. This MCS would pose a threat for strong wind gusts and large hail. ..Mosier.. 08/21/2019 Read more

WW 0605 Status Updates
STATUS REPORT ON WW 605 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 SSE CHO TO 45 WSW DCA TO 10 WNW DCA TO 20 NW DCA TO 15 WSW BWI TO 25 ESE BWI. WW 605 WILL BE ALLOWED TO EXPIRE AT 210100Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1818 ..NAUSLAR..08/21/19 ATTN...WFO...LWX... STATUS REPORT FOR WS 605 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS DCC001-210100- DC . DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE DISTRICT OF COLUMBIA MDC009-017-033-037-210100- MD . MARYLAND COUNTIES INCLUDED ARE CALVERT CHARLES PRINCE GEORGES ST. MARYS VAC013-059-099-153-177-179-510-600-610-630-683-685-210100- VA Read more

WW 0605 Status Updates
STATUS REPORT ON WW 605 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 SSE CHO TO 45 WSW DCA TO 10 WNW DCA TO 20 NW DCA TO 15 WSW BWI TO 25 ESE BWI. WW 605 WILL BE ALLOWED TO EXPIRE AT 210100Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1818 ..NAUSLAR..08/21/19 ATTN...WFO...LWX... STATUS REPORT FOR WS 605 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS DCC001-210100- DC . DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE DISTRICT OF COLUMBIA MDC009-017-033-037-210100- MD . MARYLAND COUNTIES INCLUDED ARE CALVERT CHARLES PRINCE GEORGES ST. MARYS VAC013-059-099-153-177-179-510-600-610-630-683-685-210100- VA Read more

WW 0605 Status Updates
STATUS REPORT ON WW 605 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 SSE CHO TO 45 WSW DCA TO 10 WNW DCA TO 20 NW DCA TO 15 WSW BWI TO 25 ESE BWI. WW 605 WILL BE ALLOWED TO EXPIRE AT 210100Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1818 ..NAUSLAR..08/21/19 ATTN...WFO...LWX... STATUS REPORT FOR WS 605 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS DCC001-210100- DC . DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE DISTRICT OF COLUMBIA MDC009-017-033-037-210100- MD . MARYLAND COUNTIES INCLUDED ARE CALVERT CHARLES PRINCE GEORGES ST. MARYS VAC013-059-099-153-177-179-510-600-610-630-683-685-210100- VA Read more

WW 0604 Status Updates
STATUS REPORT ON WW 604 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 E UNO TO 20 SSW POF TO 20 N DYR TO 40 WSW HOP TO 25 SSE BWG TO 65 W LOZ TO 35 ESE LEX. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1817 ..NAUSLAR..08/20/19 ATTN...WFO...PAH...LMK... STATUS REPORT FOR WS 604 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC053-057-171-207-210040- KY . KENTUCKY COUNTIES INCLUDED ARE CLINTON CUMBERLAND MONROE RUSSELL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0604 Status Updates
STATUS REPORT ON WW 604 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 E UNO TO 20 SSW POF TO 20 N DYR TO 40 WSW HOP TO 25 SSE BWG TO 65 W LOZ TO 35 ESE LEX. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1817 ..NAUSLAR..08/20/19 ATTN...WFO...PAH...LMK... STATUS REPORT FOR WS 604 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC053-057-171-207-210040- KY . KENTUCKY COUNTIES INCLUDED ARE CLINTON CUMBERLAND MONROE RUSSELL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0604 Status Updates
STATUS REPORT ON WW 604 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 E UNO TO 20 SSW POF TO 20 N DYR TO 40 WSW HOP TO 25 SSE BWG TO 65 W LOZ TO 35 ESE LEX. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1817 ..NAUSLAR..08/20/19 ATTN...WFO...PAH...LMK... STATUS REPORT FOR WS 604 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC053-057-171-207-210040- KY . KENTUCKY COUNTIES INCLUDED ARE CLINTON CUMBERLAND MONROE RUSSELL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0606 Status Updates
STATUS REPORT ON WW 606 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NE SDF TO 20 W LUK TO 30 SW DAY TO 35 WNW DAY. ..NAUSLAR..08/20/19 ATTN...WFO...ILN... STATUS REPORT FOR WS 606 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC015-037-077-081-117-187-191-202240- KY . KENTUCKY COUNTIES INCLUDED ARE BOONE CAMPBELL GALLATIN GRANT KENTON OWEN PENDLETON OHC017-025-061-113-135-165-202240- OH . OHIO COUNTIES INCLUDED ARE BUTLER CLERMONT HAMILTON MONTGOMERY PREBLE WARREN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0606 Status Updates
STATUS REPORT ON WW 606 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NE SDF TO 20 W LUK TO 30 SW DAY TO 35 WNW DAY. ..NAUSLAR..08/20/19 ATTN...WFO...ILN... STATUS REPORT FOR WS 606 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC015-037-077-081-117-187-191-202240- KY . KENTUCKY COUNTIES INCLUDED ARE BOONE CAMPBELL GALLATIN GRANT KENTON OWEN PENDLETON OHC017-025-061-113-135-165-202240- OH . OHIO COUNTIES INCLUDED ARE BUTLER CLERMONT HAMILTON MONTGOMERY PREBLE WARREN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0606 Status Updates
STATUS REPORT ON WW 606 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NE SDF TO 20 W LUK TO 30 SW DAY TO 35 WNW DAY. ..NAUSLAR..08/20/19 ATTN...WFO...ILN... STATUS REPORT FOR WS 606 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC015-037-077-081-117-187-191-202240- KY . KENTUCKY COUNTIES INCLUDED ARE BOONE CAMPBELL GALLATIN GRANT KENTON OWEN PENDLETON OHC017-025-061-113-135-165-202240- OH . OHIO COUNTIES INCLUDED ARE BUTLER CLERMONT HAMILTON MONTGOMERY PREBLE WARREN THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0604 Status Updates
STATUS REPORT ON WW 604 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NE FAM TO 15 W MDH TO 25 ESE MDH TO 5 SW EVV TO 45 WNW SDF TO 40 SE BMG TO 55 SE IND. ..CONIGLIO..08/20/19 ATTN...WFO...PAH...LMK... STATUS REPORT FOR WS 604 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC003-069-087-127-151-153-181-202130- IL . ILLINOIS COUNTIES INCLUDED ARE ALEXANDER HARDIN JOHNSON MASSAC POPE PULASKI UNION INC019-043-061-077-123-143-147-175-202130- IN . INDIANA COUNTIES INCLUDED ARE CLARK FLOYD HARRISON JEFFERSON PERRY SCOTT SPENCER WASHINGTON KYC007-027-029-033-039-055-059-075-083-085-091-093-101-103-105- 107-111-123-139-143-145-149-157-163-177-179-183-185-211-215-223- 225-233-202130- Read more

WW 604 SEVERE TSTM IL IN KY MO 201845Z - 210100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 604 NWS Storm Prediction Center Norman OK 145 PM CDT Tue Aug 20 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Southern Indiana Western and northern Kentucky Southeastern Missouri * Effective this Tuesday afternoon and evening from 145 PM until 800 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...Thunderstorms will continue to develop along an outflow boundary that will progress southeastward through the afternoon. The storm environment ahead of the boundary favors multicell clusters capable of producing damaging winds with downbursts through the remainder of the afternoon. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 25 miles north northwest of Poplar Bluff MO to 30 miles northeast of Louisville KY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 602...WW 603... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 30020. ...Thompson Read more

MD 1813 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHEAST WY...WESTERN NE PANHANDLE...FAR NORTHERN CO
Mesoscale Discussion 1813 NWS Storm Prediction Center Norman OK 0330 PM CDT Tue Aug 20 2019 Areas affected...southeast WY...western NE Panhandle...far northern CO Concerning...Severe potential...Watch possible Valid 202030Z - 202130Z Probability of Watch Issuance...60 percent SUMMARY...Isolated storms are forecast to develop over the next 1-3 hours. Storm coverage will likely increase during the evening. Large to very large hail is possible with any supercell developing in the moist axis over southeast WY and the NE Panhandle. Elsewhere, microbursts (isolated severe gusts) associated with high-based thunderstorms are possible. DISCUSSION...Visible satellite imagery shows convective initiation occurring near the WY/NE/SD border with a separate area of agitated cumulus located east of the Front Range in far northern CO. Despite neutral to weak mid-level height rises, low-level upslope flow and strong heating are contributing to storm development over the central High Plains. Forecast soundings indicate effective shear supportive of supercells but becoming more marginal with southward extent. Very steep 700-500mb lapse (9-9.5 deg C/km) rates sampled by the Denver and North Platte raobs this morning will favor hail growth and downdraft potential with stronger storms. A severe thunderstorm watch will likely need to be considered before storms are expected to increase in coverage with several of these likely becoming severe. ..Smith/Thompson.. 08/20/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...UNR...BOU...CYS... LAT...LON 42860478 43080441 42930319 41230330 40650391 40740504 42860478 Read more