Special Weather Statement, NWS Denver/Boulder, CO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
723 PM MDT WED AUG 6 2014

.UPDATE...
ISSUED AT 656 PM MDT WED AUG 6 2014

RADAR TRENDS REQUIRED SOME SMALL CHANGES TO POPS THIS
EVENING...CONVECTION SHOULD STILL START TO WIND DOWN
LATER THIS EVENING. 18Z MODELS SHOW VERY MOIST BOUNDARY LAYER
CONDITIONS IN NORTHEAST COLORADO...FOG STILL LOOKS LIKELY...BUT
WILL EXTEND IT A BIT WESTWARD DOWN THE PLATTE.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 335 PM MDT WED AUG 6 2014

ISOLATED THUNDERSTORMS ARE BEGINNING TO FORM AND MOVE EAST THIS
AFTERNOON. PRECIPITABLE WATER VALUES ARE A QUARTER TO A THIRD OF
AN INCH DRIER THAN THIS TIME YESTERDAY. THIS COUPLED WITH FASTER
MOVING STORMS WILL LESSEN THE HEAVY RAIN AND POTENTIAL FLOOD
ISSUES TODAY. AN UPPER RIDGE IS MOVING OVERHEAD WITH WARMING
TEMPERATURES ALOFT...BUT ENOUGH MOISTURE IS UNDERNEATH IT TO KEEP
THIS CONVECTIVE ACTIVITY ISOLATED TO SCATTERED LEVELS THIS
AFTERNOON AND INTO THE EVENING. BRIEF MODERATE RAIN...LIGHTNING
AND GUSTY WINDS WILL BE THE MAIN IMPACTS FROM STORMS THIS
CONVECTION. HI RES MODELS CONTINUE TO SHOW WEAK CONVECTION THROUGH
THE EVENING AND PAST MIDNIGHT...MAINLY OVER THE SOUTHERN
FOOTHILLS...PARK COUNTY AND PALMER DIVIDE. WITH A SLIGHT PUSH
OVERNIGHT FROM THE HIGH SURFACE PRESSURE OVER THE NORTHERN GREAT
PLAINS AND SOME RESIDUAL MOISTURE...THIS MAY STILL BE ABLE TO
OCCUR. LEFT IN SOME VERY LOW CHANCES OF PRECIPITATION PAST
MIDNIGHT FOR THIS. WILL LIKELY SEE SOME AREAS OF LOW CLOUDS OR FOG
AGAIN OVER THE FAR NORTHEAST CORNER...MAINLY SEDGWICK AND
PHILLIPS COUNTIES.

FLOW ALOFT WILL BECOME SOUTHWESTERLY OVERNIGHT AS A SHORTWAVE
TROUGH OVER THE GREAT BASIN LIFTS AND MOVES OVER WYOMING. THE
ENERGY FROM THIS ALONG WITH ADDITIONAL MOISTURE THATS ADVECTING IN
FROM THE SOUTH WILL LEAD TO MORE COVERAGE OF THUNDERSTORMS
TOMORROW. MODELS ARE POINTING TO THE LATE AFTERNOON FOR THE
DISTURBANCE TO COMBINE WITH A RIDGE OF THETA-E OVER THE
NORTHEASTERN PLAINS FOR A GOOD CHANCE FOR RAIN.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 335 PM MDT WED AUG 6 2014

SOME STORMS POSSIBLE ACROSS THE AREA THURSDAY EVENING...MAINLY
OVER THE FAR EASTERN PLAINS IN AREA OF WEAK MID LEVEL ASCENT.
AIRMASS FAIRLY MOIST WITH PRECIPITABLE WATER VALUES AROUND AN
INCH ACROSS THE PLAINS...SO SOME STORMS COULD PRODUCE BRIEF HEAVY
RAIN. BUT STORM MOTION SHOULD LIMIT ANY FLASH FLOOD THREAT. BY
MIDNIGHT...MODELS STILL SHOWING STORMS OVER THE FAR EASTERN PLAINS
TO CONSOLIDATE INTO A MESOSCALE CONVECTIVE SYSTEM WHICH HEADS INTO.
KANSAS OVERNIGHT. MOST OF THE STORMS ACROSS THE AREA TO END AROUND
MIDNIGHT...WITH SOME STORMS LINGERING OVER THE FAR EASTERN PLAINS
OVERNIGHT. LATEST BOUNDARY LAYER WIND AND RH PROGS SUGGESTING SOME
SORT OF OUTFLOW FROM THIS COMPLEX MOVING WEST ACROSS THE PLAINS.
THUS THERE MAY BE SOME STRATUS AROUND TOWARDS MORNING. ON
FRIDAY...SOME STRATUS WILL BE POSSIBLE DURING THE EARLY MORNING.
OTHERWISE AN UPPER TROUGH EXPECTED TO MOVE ACROSS WYOMING WHICH
FLATTENS THE RIDGE OVER COLORADO. COMBINATION OF A FAIRLY MOIST
AIRMASS AND WEAK MID LEVEL ASCENT ENOUGH TO GENERATE SOME STORMS
BY THE AFTERNOON. ONLY CONCERN IS THAT AIRMASS ACROSS PLAINS MIGHT
END UP BEING TOO STABLE FOR ANY CONVECTION. DID LOWER THE POPS
SLIGHTLY TO TAKE THIS INTO ACCOUNT. SOME STORMS COULD PRODUCE
BRIEF HEAVY RAIN ACROSS THE PLAINS. STORM CHANCES TO DECREASE
DURING THE EVENING AS ASCENT MOVES INTO KANSAS AND SHOULD END
AROUND MIDNIGHT WITH GRADUALLY CLEARING SKIES. AIRMASS SLIGHTLY
COOLER WITH TEMPERATURES A BIT BELOW AVERAGE. FOR SATURDAY...
POTENTIAL FOR SOME STRATUS ACROSS THE FAR NORTHEAST PLAINS DURING
THE MORNING. MODELS ARE HINTING AT A DENVER CYCLONE DEVELOPING
WHICH COULD DRAW THE STRATUS CLOSER TO THE FOOTHILLS.
OTHERWISE...WEST SOUTHWEST FLOW ALOFT TO DRAW SOME MONSOONAL
MOISTURE INTO COLORADO. THERE ARE HINTS OF A MID LEVEL SHORTWAVE
CLIPPING THE NORTHEAST CORNER DURING THE AFTERNOON. COMBINATION OF
MOISTURE AND INSTABILITY TO PRODUCE SOME STORMS ACROSS THE AREA
DURING THE AFTERNOON AND EVENING. BEST CHANCE FOR STORMS LOOKS TO
BE ACROSS THE FAR NORTHEAST PLAINS WHERE THERE IS SOME MID LEVEL
ASCENT. AGAIN STORMS COULD PRODUCE BRIEF HEAVY RAIN ACROSS THE
PLAINS. ON SUNDAY...WEST SOUTHWEST FLOW ALOFT ACROSS COLORADO
WHICH SHOULD KEEP THE MONSOONAL FLOW OVER THE AREA. MODELS STILL
SHOWING THE BEST CHANCE FOR STORMS OVER THE MOUNTAINS...WILL KEEP
THE HIGHER POPS THERE. TEMPERATURES BOTH SATURDAY AND SUNDAY TO BE
SLIGHTLY BELOW AVERAGE.

FOR THE LATER DAYS...MONDAY THROUGH WEDNESDAY. BOTH ECMWF AND GFS
SHOW THE FLOW BECOMING MORE SOUTHWEST WHICH COULD BRING MORE
MONSOONAL MOISTURE INTO COLORADO. BEST CHANCE FOR STORMS TO BE
ACROSS THE MOUNTAINS. BY WEDNESDAY...MODELS SHOW AN UPPER TROUGH
MOVING ACROSS WYOMING AND MONTANA. FLOW ALOFT TO BECOME
NORTHWEST...WHICH SHOULD SHUNT MOST OF THE MOISTURE SOUTH OF THE
AREA. THUS SHOULD SEE A DECREASE IN THUNDERSTORM CHANCES.
TEMPERATURES TO REMAIN SLIGHTLY BELOW AVERAGE.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z THURSDAY LATE AFTERNOON)
ISSUED AT 335 PM MDT WED AUG 6 2014

A LINE OF THUNDERSTORMS RACED THROUGH THE METRO AREA EARLY THIS
EVENING...THERE IS STILL SOME CONVECTION OVER THE HIGHER TERRAIN
WHICH MAY ALSO MOVE THROUGH...BUT IT SHOULD NOT CREATE AS MUCH AN
IMPACT AS THE LOWER ATMPOSPHERE STARTS TO STABLILIZE AS THE SUN
GOES DOWN. VFR CONDITIONS WILL PREVAIL THROUGH EARLY AFTERNOON ON
THURSDAY...THEN SCATTERED THUNDERSTORMS WILL LIKELY MOVE NEAR ALL
AREA AIRPORTS...AND WE MAY HAVE SOME MVFR CEILINGS AND
VISIBILITIES IN THUNDERSTORMS THURSDAY AFTERNOON. EASTERLY
SURFACE WINDS WILL TRANSITION TO DOWNSLOPE WINDS AFTER SUNSET.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

UPDATE...RTG
SHORT TERM...KRIEDERMAN
LONG TERM...D-L
AVIATION...KRIEDERMAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1022 AM MDT WED AUG 6 2014

COZ030>051-071630-
JACKSON COUNTY BELOW 9000 FEET-
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-
GRAND AND SUMMIT COUNTIES BELOW 9000 FEET-
SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-
SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/
GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE
9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-
JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR
CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET-
CENTRAL AND SOUTHEAST PARK COUNTY-
LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-
BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD
COUNTY-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND
ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY-
ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-
NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY-
CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-
SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY-
LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY-
1022 AM MDT WED AUG 6 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON...WITH ONLY ISOLATED STORMS ON THE PLAINS. MOST OF THE
STORMS WILL ONLY PRODUCE LIGHT RAIN AND GUSTY WINDS...THOUGH A
FEW STORMS OVER THE NORTHERN PLAINS COULD PRODUCE LOCALIZED HEAVY
RAINFALL. SLIGHTLY DRIER AND WARMER AIR WILL LIMIT THE
THUNDERSTORM ACTIVITY TODAY...AND NO SEVERE STRENGTH STORMS ARE
EXPECTED.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A SERIES OF UPPER LEVEL WEATHER DISTURBANCES WITHIN A FAIRLY MOIST
WEST-SOUTHWEST FLOW ALOFT WILL PASS OVER NORTHEAST COLORADO
DURING THE AFTERNOON AND EVENING HOURS ON THURSDAY...FRIDAY AND
POSSIBLY SATURDAY. THESE DISTURBANCES WILL BRING A CHANCE OF
THUNDERSTORMS TO THE AREA EACH DAY. SOME OF THE STORMS MAY
PRODUCE LOCALLY HEAVY RAINFALL...ESPECIALLY ACROSS THE NORTHEAST
CORNER OF THE STATE THURSDAY AND FRIDAY. MOISTURE MAY BECOME MORE
WIDESPREAD ON SUNDAY AND MONDAY...WHICH COULD INCREASE THE CHANCE
FOR LATE DAY STORMS ACROSS MOST OF THE FORECAST AREA. TEMPERATURES
DURING THE PERIOD WILL GENERALLY REMAIN NEAR TO SLIGHTLY BELOW
AVERAGE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
716 PM MDT WED AUG 06 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0610 PM     TORNADO          S BENNETT               39.76N 104.42W
08/06/2014                   ADAMS              CO   BROADCAST MEDIA

            VERY WEAK AND SHORT LIVED

&&

JK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
933 PM MDT WED AUG 6 2014

COZ048-050-070415-
LOGAN COUNTY CO-SEDGWICK COUNTY CO-
933 PM MDT WED AUG 6 2014

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN SEDGWICK AND
NORTHEASTERN LOGAN COUNTIES UNTIL 1015 PM MDT...

AT 933 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER
TWIN BUTTES...OR 17 MILES SOUTHEAST OF SIDNEY...MOVING SOUTHEAST AT
20 MPH.

DIME SIZE HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
CROOK AND TWIN BUTTES.

LAT...LON 4084 10284 4100 10292 4100 10258 4085 10251
TIME...MOT...LOC 0333Z 315DEG 18KT 4093 10277

RTG