Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 232315
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
515 PM MDT WED JUL 23 2014

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 240 PM MDT WED JUL 23 2014

WATER VAPOR IMAGERY SHOWS STRONG UPPER RIDGING ACROSS MUCH OF THE
WRN TO CNTRL CONUS WITH THE MAIN AXIS FROM CO TO MT. AN UPPER LOW IS
SITTING JUST OFFSHORE THE PACIFIC NORTHWEST WITH SW FLOW OVER THE NW
CONUS...THEN TRANSITIONING TO NW FLOW OVER THE CWA. SURFACE ANALYSIS
SHOWS HIGH PRESSURE ACROSS THE UPPER MIDWEST...AND LOW PRESSURE OVER
MONTANA WITH RETURN FLOW OVER THE HIGH PLAINS. TEMPS HAVE STRUGGLED
TO REACH FORECAST HIGHS WITH TEMPS SO FAR IN THE 80S TO LOWER 90S.

STRONG CAP IN PLACE ACROSS MUCH OF THE CWA WILL KEEP DIURNALLY
TRIGGERED CONVECTION FROM DEVELOPING TODAY. THE CAP WAS EXPECTED TO
BE WEAKEST ACROSS NE WY WHERE TEMPS REACHING MID 90S WOULD BE ENOUGH
TO ERODE IT...BUT TEMPS HAVE BEEN SHORT OF THAT SO FAR. CONVECTION
HAS INITIATED OVER LARAMIE RANGE...AND THE LATEST HRRR RUN SHOWS
THIS CONVECTION MOVING N/NE INTO NE WY AND SW SD THIS EVENING. HAVE
PUT IN ISOLATED POPS THIS EVENING TO ACCOUNT FOR THIS...AND POSSIBLE
OTHER CONVECTION THAT MOVES IN FROM THE WEST. BUT OVERALL MOST AREAS
WILL STAY DRY TONIGHT. ANY STORMS THAT MAKE IT INTO THE AREA MAY BE
SEVERE...BUT OVERALL SEVERE THREAT TONIGHT IS VERY LOW.

UPPER RIDGE AXIS SLIDES EASTWARD THURSDAY...CROSSING THE NRN PLAINS.
UPPER LOW WILL CROSS THE NRN ROCKIES WITH THE SURFACE LOW PUSHING
ACROSS THE CWA. TEMPS ARE EXPECTED TO REACH THE 90S TO 100. A COLD
FRONT WILL SLIDE SE...CROSSING THE CWA THU AFTN/NIGHT. A STRONG CAP
IN PLACE AGAIN WILL HELP KEEP CONVECTION FROM DEVELOPING...BUT COULD
SEE ISOLATED STORMS DEVELOP AS THE FRONT PUSHES THROUGH...PERHAPS
ELEVATED STORMS. CANT RULE OUT A COUPLE STORMS BECOMING SEVERE...BUT
OVERALL THREAT LOOKS MINIMAL AGAIN.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 240 PM MDT WED JUL 23 2014

UPPER-LEVEL RIDGE OVER THE REGION BREAKS DOWN BY THE END OF THE WEEK
AS AN UPPER LOW SLIDES SOUTHEAST ACROSS SOUTH CENTRAL CANADA. A WEAK
SHORTWAVE IN ZONAL FLOW TO THE SOUTH COULD BRING ANOTHER CHANCE FOR
SHOWERS AND THUNDERSTORMS TO AT LEAST PORTIONS OF THE CWA FRIDAY
AFTERNOON AND NIGHT.

AS THE UPPER LOW SLIDES FURTHER EAST OF THE REGION...THE UPPER RIDGE
WILL REBUILD OVER THE WESTERN CONUS...BRINGING PREDOMINANTLY
NORTHWEST FLOW TO THE NORTHERN PLAINS. THIS WILL RESULT IN COOLER
TEMPERATURES FOR THE REST OF THE EXTENDED PERIOD...ALONG WITH MAINLY
DRY CONDITIONS FROM SATURDAY THROUGH MONDAY. WEAK SHORTWAVE
DISTURBANCES WILL BEGIN TO ROTATE AROUND THE RIDGE AND INTO THE
NORTHERN PLAINS AGAIN BY THE MIDDLE OF NEXT WEEK. WILL KEEP LOW
CHANCE POPS ACROSS PORTIONS OF THE AREA FROM MONDAY NIGHT THROUGH
WEDNESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 512 PM MDT WED JUL 23 2014

ISOLATED THUNDERSTORMS ARE POSSIBLE THROUGH THE NIGHT...WITH LCL
MVFR VSBY AND GUSTY WINDS. OTHERWISE VFR CONDITIONS EXPECTED
THROUGH THURSDAY MORNING. ADDITIONAL THUNDERSTORMS EXPECTED
THURSDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...13
LONG TERM...26
AVIATION...7






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