Alert archive / Nebraska / Special Weather Statements in 2015
Special Weather Statement, NWS Cheyenne, WY
NWS Cheyenne, WY issued this special weather statement at Aug 1, 2015, 1:49 PM MDT for Sioux County, Nebraska. It was in force for 26 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
- Aug 1, 2015, 1:49 PM MDT (19:49 UTC)
- Expired
- Aug 1, 2015, 2:15 PM MDT
- In force
- 26 min
- Issued by
- NWS Cheyenne, WY
County Sioux County, NE
The radar
The Cheyenne radar (KCYS), 149 km from the middle of the area, began a volume at 19:53 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.
The nearest sounding before it
Denver, CO (KDEN), launched 12:00Z, 7.8 hours before the alert went out and 260 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
- 50 J/kg
- Mixed-layer CIN
- -288 J/kg
- Mixed-layer LCL
- 2113 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- -22 m²/s²
- 0-3 km storm-relative helicity
- 32 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>What forecasters said that day
The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Cheyenne, WY wrote its last area forecast discussion before this special weather statement went out at Aug 1, 11:32 AM MDT, 2 hours 17 minutes earlier.
Area forecast discussion, Aug 1, 11:32 AM MDT, 2 hours 17 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHEYENNE WY 1132 AM MDT SAT AUG 1 2015 .SHORT TERM...(TODAY THROUGH MONDAY NIGHT) ISSUED AT 152 AM MDT SAT AUG 1 2015 TODAY...FLOW ALOFT REMAINS NORTHWEST. IN THE AFTERNOON...NAM PROGS A LOW LEVEL CONVERGENCE AXIS TO SETUP FROM NEAR CHEYENNE TO NEAR CHADRON WITH A LOW AND MID LEVEL THETA-E RIDGE AXIS ALSO SETTING UP SOUTH OF THE CHEYENNE TO CHADRON LINE. LOOKS LIKE ENOUGH LOW LEVEL CONVERGENCE DESPITE THE WARM TEMPERATURES ALOFT TO SPARK ISOLATED AFTERNOON THUNDERSTORMS ALONG THE CONVERGENCE AXIS AND WILL CONTINUE TO PAINT 10 TO 25 PERCENT POPS...DRY ELSEWHERE. TONIGHT...ISOLATED THUNDERSTORMS SHOULD QUICKLY END IN THE EVENING WITH LOSS OF DAYTIME HEATING...WITH DECREASING CLOUD COVER. SUNDAY/SUNDAY NIGHT...AGAIN...WARM TEMPERATURES AT MID LEVELS WILL LIMIT CONVECTIVE POTENTIAL AND CONVECTIVE DEVELOPMENT. HOWEVER...WITH A LOW LEVEL INSTABILITY AXIS FROM NEAR GRAND JUNCTION COLORADO TO DOUGLAS WYOMING...BELIEVE THAT ISOLATED THUNDERSTORMS WILL BE SPARKED IN THE AFTERNOON OVER MUCH OF ALBANY COUNTY NEAR LARAMIE AND OVER SOUTHERN LARAMIE COUNTY NEAR CHEYENNE. STORMS EXPECTED TO END SUNDAY EVENING WITH LOSS OF DAYTIME HEATING. MONDAY/MONDAY NIGHT...MODELS FORECAST THE LOW AND MID LEVEL MONSOONAL MOISTURE TO SLIDE ACROSS OUR COUNTIES AND COMBINED WITH A NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT...WE EXPECT SCATTERED TO NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS TO ERUPT IN THE AFTERNOON AND EVENING...MAINLY ALONG AND WEST OF INTERSTATE 25 NEAR THE LOW AND MID LEVEL THETA-E RIDGE AXIS. .LONG TERM...(TUESDAY THROUGH FRIDAY) ISSUED AT 300 AM MDT SAT AUG 1 2015 STILL A LOT OF FLIP FLOPPING WITH MEDIUM RANGE GUIDANCE ON WHAT IS GOING TO HAPPEN IN THE LONG TERM. NOW THE GFS IS THE MORE BULLISH ON POPS AND QPF FOR TUESDAY. ECMWF WAS THE MORE BULLISH 24 HOURS AGO. LEADS TO LESS CONFIDENCE WITH THESE RUN TO RUN INCONSISTENCIES. BOTH BRING A SHORTWAVE THROUGH THE CWFA MONDAY NIGHT INTO TUESDAY. GFS BRINGS THE SHORTWAVE FURTHER NORTH WHILE THE ECMWF HAS THE SHORTWAVE TRACKING ALONG THE COLORADO/WYOMING BORDER. DECIDED TO MAINTAIN LOW CHANCE TO SLIGHT CHANCE POPS IN THE FORECAST FOR TUESDAY WITH THE HOPES THAT RUN TO RUN CONSISTENCY INCREASES IN ORDER TO RAISE POPS AS THE EVENT DRAWS CLOSER. SHOULD THE GFS SOLUTION CURRENTLY BEING PROPOSED HOLDS TRUE...PANHANDLE AND EXTREME SOUTHEAST WYOMING ZONES WOULD BE IN FOR HEAVY RAINFALL. GFS FORECAST OVER 2 INCHES OF RAIN IN THE PANHANDLE FOR TUESDAY AS THE FRONT STALLS ALONG THE LARAMIE RANGE. BOTH MODELS SHOWING A FAIRLY DRY DAY WEDNESDAY AS SHORTWAVE MOVES EAST AND IS REPLACED WITH UPPER LEVEL RIDGING. SURFACE BOUNDARY GETS FORCED OUT INTO THE PANHANDLE WEDNESDAY AFTERNOON. MOST OF SOUTHEAST WYOMING WOULD BE DRY AS WESTERLY WINDS CREATE DRY DOWNSLOPING CONDITIONS OFF THE LARAMIE RANGE. COULD BE QUITE BREEZY OUT WEST WEDNESDAY AS GFS 700MB WINDS INCREASE TO 30-35KTS. IN FACT...THE GFS SHOWS THESE STRONG WESTERLY WINDS CONTINUING FOR THE REST OF THE WEEK. WE WOULD BE DEALING WITH ELEVATED TO CRITICAL FIRE WEATHER ISSUES UNDER THIS SCENARIO FOR MUCH OF NEXT WEEK AS AFTERNOON HUMIDITIES LIKELY TO BECOME CRITICAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH SUNDAY MORNING) ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED ONCE AGAIN THIS AFTERNOON FOR AIRPORTS EAST OF THE LARAMIE RANGE. GREATEST CONCENTRATION WILL BE IN THE NEBRASKA PANHANDLE. IT WILL BE MAINLY DRY WEST OF THE LARAMIE RANGE TODAY WITH RELATIVELY LIGHT WINDS AND VFR CONDITITIONS. && .FIRE WEATHER... ISSUED AT 152 AM MDT SAT AUG 1 2015 LOW AFTERNOON RELATIVE HUMIDITIES WEST OF INTERSTATE 25 TODAY AND SUNDAY...THOUGH FORTUNATELY...WINDS AND WIND GUSTS WILL REMAIN BELOW CRITERIA FOR A MAJORITY OF LOCATIONS. RAIN CHANCES INCREASE MONDAY AND TUESDAY AS MONSOONAL MOISTURE CREEPS BACK INTO OUR COUNTIES. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && SHORT TERM...RUBIN LONG TERM...GCC AVIATION...TJT FIRE WEATHER...RUBIN
Hazardous weather outlook, Aug 1, 4:39 AM MDT, 9 hours 10 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHEYENNE WY 439 AM MDT SAT AUG 1 2015 WYZ101>119-021045- CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY- NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS- SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY- EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY- NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY- SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE- LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS- CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY- 439 AM MDT SAT AUG 1 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WYOMING...SOUTH CENTRAL WYOMING AND SOUTHEAST WYOMING. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON FOR AREAS EAST OF THE LARAMIE RANGE IN SOUTHEAST WYOMING. THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED MUCH OF THE PERIOD AS MONSOON MOISTURE RETURNS TO THE AREA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. NEZ002-003-019>021-054-055-095-096-021045- DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE- NORTH SIOUX-SOUTH SIOUX- 439 AM MDT SAT AUG 1 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN NEBRASKA. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON FOR AREAS IN THE CENTRAL AND SOUTHERN NEBRASKA PANHANDLE. THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED MUCH OF THE PERIOD AS MONSOON MOISTURE RETURNS TO THE AREA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.
In the hours before
Special weather statement, Aug 1, 1:49 PM MDT, 0 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHEYENNE WY 149 PM MDT SAT AUG 1 2015 NEZ003-096-012015- SOUTH SIOUX NE-BOX BUTTE NE- 149 PM MDT SAT AUG 1 2015 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN SIOUX AND WESTERN BOX BUTTE COUNTIES UNTIL 215 PM MDT... AT 149 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 13 MILES SOUTH OF AGATE BED NATIONAL MONUMENT...OR 24 MILES NORTH OF SCOTTSBLUFF...MOVING SOUTHEAST AT 10 MPH. HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF SOUTHEASTERN SIOUX AND WESTERN BOX BUTTE COUNTIES. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE A BUILDING OR VEHICLE. && LAT...LON 4221 10379 4229 10369 4219 10344 4204 10365 TIME...MOT...LOC 1949Z 319DEG 10KT 4222 10369 MAZUR
The office that day
Everything else NWS Cheyenne, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 2:22 PM MDT | Special Weather Statement | CYS | Scotts Bluff | 38 min |
| Aug 1, 3:05 PM MDT | Special Weather Statement | CYS | Box Butte | 40 min |
| Aug 1, 3:34 PM MDT | Special Weather Statement | CYS | Morrill | 41 min |
| Aug 1, 3:42 PM MDT | Severe Thunderstorm Warning | CYS | Morrill | 33 min |
| Aug 1, 4:18 PM MDT | Severe Thunderstorm Warning | CYS | Morrill | 42 min |
| Aug 1, 4:37 PM MDT | Severe Thunderstorm Warning | CYS | Morrill | 38 min |
| Aug 1, 4:58 PM MDT | Severe Thunderstorm Warning | CYS | Cheyenne, Morrill | 47 min |
| Aug 1, 5:18 PM MDT | Special Weather Statement | CYS | Cheyenne | 42 min |
| Aug 1, 5:39 PM MDT | Special Weather Statement | CYS | Cheyenne | 36 min |
Nearby
Special Weather Statements in Nebraska, 2015Every special weather statement in 2015
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.