Alert archive / Utah / Severe Thunderstorm Warnings in 2011
Severe Thunderstorm Warning 55, NWS Salt Lake City, UT
NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 27, 2011, 4:15 PM MDT for Utah County, Utah. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 27, 2011, 4:15 PM MDT (22:15 UTC)
- Expired
- Jul 27, 2011, 4:45 PM MDT
- In force
- 30 min
- Issued by
- NWS Salt Lake City, UT
- Area
- Storm-based polygon
County Utah County, UT
The radar
The Salt Lake City radar (KMTX), 148 km from the middle of the area, began a volume at 22:16 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The nearest sounding before it
Salt Lake City I, UT (KSLC), launched 12:00Z, 10.3 hours before the alert went out and 80 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 34 J/kg
- Mixed-layer CIN
- -261 J/kg
- Mixed-layer LCL
- 1858 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 66 m²/s²
- 0-3 km storm-relative helicity
- 44 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
392 WUUS55 KSLC 272215 SVRSLC UTC049-272245- /O.NEW.KSLC.SV.W.0055.110727T2215Z-110727T2245Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SALT LAKE CITY UT 415 PM MDT WED JUL 27 2011 THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CENTRAL UTAH COUNTY IN UTAH * UNTIL 445 PM MDT * AT 412 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED JUST NORTH OF PAYSON...MOVING EAST AT 20 MPH. * LOCATIONS IN THE WARNING INCLUDE... SALEM... SPRINGVILLE... SPANISH FORK AND MAPLETON PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. && LAT...LON 4018 11132 3989 11146 4002 11189 4027 11183 TIME...MOT...LOC 2214Z 288DEG 17KT 4010 11172 $$ TRAPHAGAN
2 follow-up statements
241 WWUS55 KSLC 272230 SVSSLC SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE SALT LAKE CITY UT 430 PM MDT WED JUL 27 2011 UTC049-272245- /O.CON.KSLC.SV.W.0055.000000T0000Z-110727T2245Z/ UTAH UT- 430 PM MDT WED JUL 27 2011 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM MDT FOR CENTRAL UTAH COUNTY... AT 430 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR SPANISH FORK...OR ABOUT 7 MILES NORTHEAST OF PAYSON... MOVING EAST AT 20 MPH. * LOCATIONS IN THE WARNING INCLUDE... SPANISH FORK AND MAPLETON PRECAUTIONARY/PREPAREDNESS ACTIONS... IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. && LAT...LON 4018 11132 3989 11146 4002 11189 4027 11183 TIME...MOT...LOC 2230Z 288DEG 17KT 4007 11161 $$ TRAPHAGAN
736 WWUS55 KSLC 272244 SVSSLC SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE SALT LAKE CITY UT 444 PM MDT WED JUL 27 2011 UTC049-272254- /O.EXP.KSLC.SV.W.0055.000000T0000Z-110727T2245Z/ UTAH UT- 444 PM MDT WED JUL 27 2011 ...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL UTAH COUNTY WILL EXPIRE AT 445 PM MDT... THE STORM HAS WEAKENED AND IS NO LONGER SEVERE. THEREFORE THE WARNING HAS BEEN ALLOWED TO EXPIRE. LAT...LON 4018 11132 3989 11146 4002 11189 4027 11183 TIME...MOT...LOC 2244Z 288DEG 17KT 4005 11153 $$ TRAPHAGAN
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Salt Lake City, UT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 27, 3:28 PM MDT, 47 minutes earlier.
Area forecast discussion, Jul 27, 3:28 PM MDT, 47 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SALT LAKE CITY UT 328 PM MDT WED JUL 27 2011 .SYNOPSIS...LINGERING MOISTURE WILL REMAIN IN PLACE THROUGH THE REMAINDER OF THE WEEK. A VERY MOIST AIRMASS IS EXPECTED TO SPREAD BACK INTO UTAH DURING THE UPCOMING WEEKEND THROUGH EARLY NEXT WEEK. && .DISCUSSION...THE AIRMASS ACROSS THE FORECAST AREA CONTINUES TO SLOWLY DRY THIS AFTERNOON UNDER WESTERLY FLOW ALOFT. PWS IN THE 0.4-0.6 INCH RANGE HAVE MADE THEIR WAY INTO NORTHWEST UTAH...THOUGH PWS IN THE 0.7-0.8 ARE MORE COMMON ACROSS THE STATE...AND VALUES ABOVE 1.0 INCH REMAIN OVER SOUTHEAST UTAH. CONVECTION THIS AFTERNOON HAS DEVELOPED PRIMARILY OVER CENTRAL UTAH...COINCIDENT WITH THE BEST JET SUPPORT AND A FAVORABLE MOISTURE GRADIENT. THE MODEST DRYING TREND IS PROGGED TO CONTINUE THROUGH FRIDAY...WITH COVERAGE OF CONVECTION DECREASING A BIT BEGINNING TOMORROW AS THE BEST JET SUPPORT MOVES EAST OF THE AREA AND A MORE SUBSIDENT AIRMASS MOVES IN. STILL..ISOLATED CONVECTION IS A THREAT FOR MOST AREAS TOMORROW...WITH THE EXCEPTION OF NORTHWEST UTAH. BY SATURDAY...GLOBAL MODELS CONTINUE TO INDICATE THE FLOW ALOFT WILL BECOME MORE SATURDAY ON THE BACK SIDE OF A BUILDING RIDGE. THIS WILL ALLOW MONSOONAL MOISTURE TO RAPIDLY RETURN TO THE FORECAST AREA THROUGH AT LEAST EARLY NEXT WEEK...RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EACH AFTERNOON WITH SOME LINGERING INTO THE EVENING AND OVERNIGHT HOURS...ALL CAPABLE OF PRODUCING HEAVY RAIN. THE 12Z GFS INDICATES THAT THE FLOW ALOFT WILL BECOME WESTERLY AGAIN BEGINNING TUESDAY AS A PACIFIC TROUGH APPROACHES THE COAST...ALLOWING FOR ANOTHER DRYING TREND. THIS TROUGH IS FARTHER SOUTH IN THE EC SOLUTION...ALLOWING THE FLOW TO REMAIN MORE SOUTHERLY AND CONTINUED MOIST THROUGH MUCH OF NEXT WEEK. && .AVIATION...NORTHERLY WINDS WILL CONTINUE AT THE SLC TERMINAL THROUGH AROUND 03Z. WINDS SHOULD THEN TURN SOUTHEAST. THERE IS A 20 PERCENT CHANCE THAT A THUNDERSTORM COULD MOVE NEAR THE AIRFIELD AND BUMP THE WINDS....DIRECTION DEPENDING ON PROXIMITY TO THE AIRFIELD. OTHERWISE...VFR CONDITIONS UNDER PARTLY CLOUDY SKIES WILL CONTINUE. && .FIRE WEATHER...WHILE AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT ANYWHERE ACROSS THE STATE FOR THE REST OF THIS AFTERNOON AND THIS EVENING...THE BEST THUNDERSTORM COVERAGE AND CHANCE FOR A WETTING RAIN WILL BE IN SOUTH CENTRAL UTAH. THESE STORMS CAN ALSO BRING CLOUD TO GROUND LIGHTNING...LOCALLY GUSTY WINDS AND SMALL HAIL. A DRIER AND MORE STABLE AIRMASS WILL SPREAD SOUTH ACROSS NORTHERN UTAH TOMORROW...SUPPRESSING THE MOISTURE AND BEST CHANCES FOR A THUNDERSTORM TO THE SOUTHERN AND EASTERN PORTION OF THE STATE. MOISTURE WILL BEGIN TO SPREAD BACK NORTH FRIDAY...AND WILL DEEPEN ACROSS THE REGION THROUGH EARLY NEXT WEEK. THIS WILL AGAIN LEAD TO AN INCREASE IN THUNDERSTORM COVERAGE AND RAINFALL EFFICIENCY...WHILE MAINTAINING A THREAT OF CLOUD TO GROUND LIGHTNING THROUGH EARLY NEXT WEEK. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...NONE. WY...NONE. && PUBLIC...TRAPHAGAN FIRE WEATHER...ROGOWSKI AVIATION...YOUNG FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE) FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION VISIT... HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
Hazardous weather outlook, Jul 27, 2:56 AM MDT, 13 hours 19 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SALT LAKE CITY UT 256 AM MDT WED JUL 27 2011 UTZ001>016-019>021-517-518-WYZ021-281100- CACHE VALLEY/UTAH PORTION-NORTHERN WASATCH FRONT- SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH FRONT- GREAT SALT LAKE DESERT AND MOUNTAINS-WASATCH MOUNTAIN VALLEYS- WASATCH MOUNTAINS I-80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80- WESTERN UINTA MOUNTAINS-WASATCH PLATEAU/BOOK CLIFFS- WESTERN UINTA BASIN-CASTLE COUNTRY-SAN RAFAEL SWELL- SANPETE/SEVIER VALLEYS-WEST CENTRAL UTAH-SOUTHWEST UTAH- UTAHS DIXIE AND ZION NATIONAL PARK-SOUTH CENTRAL UTAH- GLEN CANYON RECREATION AREA/LAKE POWELL-CENTRAL MOUNTAINS- SOUTHERN MOUNTAINS-SOUTHWEST WYOMING- 256 AM MDT WED JUL 27 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN TWO THIRDS OF UTAH AND SOUTHWEST WYOMING. .DAY ONE...TONIGHT LINGERING MOISTURE ACROSS THE OUTLOOK AREA WILL ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS...AND ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE VALLEYS. DANGEROUS CLOUD TO GROUND LIGHTNING AND GUSTY WINDS CAN BE EXPECTED WITH THESE STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY MOISTURE LOOKS TO LINGER ACROSS THE OUTLOOK AREA THROUGH THE REMAINDER OF THE WEEK...WHICH WILL MAINTAIN A THREAT FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. DEEPER MOISTURE LOOKS TO SPREAD BACK INTO THE AREA DURING THE UPCOMING WEEKEND. THIS WILL BRING A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS...ALONG WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL ACROSS THE OUTLOOK AREA. THIS MOISTURE LOOKS TO LINGER INTO EARLY NEXT WEEK. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
The office that day
Everything else NWS Salt Lake City, UT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 8:11 PM MDT | Areal Flood Advisory | SLC | Juab, Millard | 3 hr |
| Jul 27, 3:13 PM MDT | Flash Flood Warning | SLC | Garfield, Wayne | 3 hr |
| Jul 27, 4:52 PM MDT | Flash Flood Warning | SLC | Garfield, Wayne | 3 hr |
| Jul 27, 5:45 PM MDT | Severe Thunderstorm Warning | SLC | Carbon, Duchesne | 30 min |
Nearby
Severe Thunderstorm Warnings in Utah, 2011Every severe thunderstorm warning in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.