Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 042015
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
215 PM MDT TUE AUG 4 2015

.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 209 PM MDT TUE AUG 4 2015

UPPER LOW IS SPINNING OVER EASTERN WY AS IT GRADUALLY
TRANSITIONS EASTWARD. OTHER THAN A FEW WEAK BUT RAINY
THUNDERSTORMS OVER THE NORTHERN HILLS AND BEAR LODGE MOUNTAINS...MOST
OF THE ACTIVITY IS CURRENTLY OUTSIDE THE CWA. TEMPS ARE RISING
INTO THE 80S.

STILL EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS
AFTERNOON AND THIS EVENING...BUT THE SYSTEM IS LOOKING DRIER THAN
PREVIOUSLY SO DECREASED POPS SIGNIFICANTLY ACROSS THE EASTERN CWA.
INGREDIENTS ARE STILL CONDUCIVE TO SLOW-MOVING HEAVY RAIN PRODUCING
THUNDERSTORMS...AND SO WHILE NOT A COMPLETE WASHOUT IS
EXPECTED...PLACES UNDER THE SCATTERED STORMS MAY SEE HEAVY RAIN WITH
THE POTENTIAL FOR FLASH FLOODING. INSTABILITY IS SUFFICIENT FOR
ISOLATED STRONG TO SEVERE STORMS...BUT SHEAR IS VERY WEAK AND SO
ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED. PRECIP WILL END
OVERNIGHT AS WAVE EXITS THE REGION.

MUCH OF WEDNESDAY WILL BE DRY BEFORE THE NEXT UPPER WAVE PASSES
THROUGH MAINLY WEDNESDAY NIGHT...WITH CHANCES OF SHOWERS AND
THUNDERSTORMS INCREASING IN THE AFTERNOON FROM WEST TO EAST. IN THE
AFTERNOON THE BEST CHANCE FOR AN ISOLATED STRONG TO SEVERE STORM
WILL BE OVER THE HILLS. THEN AS THE WAVE PUSHES EASTWARD INTO THE
AREA DURING THE EVENING...COULD BE ISOLATED STRONG TO SEVERE
STORMS OVER CENTRAL SD WITH ML CAPE NEAR 2000 J/KG AND 0-6 KM
SHEAR INCREASING TO 40 KTS. HOWEVER...WIDESPREAD ORGANIZED SEVERE
WEATHER IS NOT EXPECTED AND STORMS SHOULD REMAIN BELOW SEVERE
CRITERIA FOR THE MOST PART. HIGHS WEDNESDAY WILL BE IN THE
80S...WITH 70S IN THE BLACK HILLS.

.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 209 PM MDT TUE AUG 4 2015

ACTIVE PROGRESSIVE FLOW WILL DOMINATE IN THE PERIOD AS
LARGE SCALE RIDGING REMAINS SUBDUED FOR MOST OF THE PERIOD. THIS
WILL SUPPORT PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS AS A
SERIES OF TROUGHS PUSH THROUGH THE REGION. LL MOISTURE WILL BE MORE
THAN SUFFICIENT GIVEN WEAK SOUTHWARD PROTRUSION OF DRY AIR WITH
STAUNCH RETURN FLOW PER EACH SYSTEM. CARRIED LOW CHANCE POPS THROUGH
MUCH OF THE PERIOD...WITH A STRONGER SYSTEM EXPECTED THROUGH THE
REGION THIS WEEKEND SUPPORTING THE HIGHEST POPS SAT/SAT NIGHT.
FASTER FLOW ALOFT WILL SUPPORT A POTENTIAL SEVERE THREAT WITH EACH
SYSTEM...HOWEVER TIMING WILL BE KEY IN ANY COVERAGE. SEASONAL TEMPS
CAN BE EXPECTED FOR MOST OF THE PERIOD. HOWEVER...GROWING
INDICATIONS IN DETERMINISTIC AND ENSEMBLE PROGS FOR WESTERN/CENTRAL
CONUS RIDGING EARLY NEXT WEEK...WHICH WOULD SET THE STAGE FOR MUCH
WARMER CONDS IN THAT TIME FRAME.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY
ISSUED AT 209 PM MDT TUE AUG 4 2015

SHOWERS AND THUNDERSTORMS WILL REDEVELOP ACROSS THE AREA THIS
AFTERNOON AND EVENING WITH HEAVY RAIN AND IFR CIGS/VSBY. CONDS
WILL TREND VFR OVERNIGHT MOST PLACES...ALTHOUGH THERE IS SOME
POTENTIAL FOR PATCHY FOG ON THE SD PLAINS AND BLACK HILLS LATE
TONIGHT.
&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR SDZ001-012-013-
     024>026-028>031-072>074.

WY...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR WYZ056-057-071.

&&

$$

SHORT TERM...POJORLIE
LONG TERM...JC
AVIATION...JC



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