Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 201720
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1120 AM MDT SUN JUL 20 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 228 AM MDT SUN JUL 20 2014

08Z SURFACE ANALYSIS HAD WEAK RETURN FLOW OVER THE CWA WITH SOME
PASSING HIGH CLOUDS. WATER VAPOR SHOWED ZONAL FLOW WHICH WILL
CONTINUE TODAY WITH MINOR HEIGHT RISES OVER THE NORTHERN PLAINS
AND SLOWLY STRENGTHENING THERMAL RIDGE. RESULT WILL BE FILTERED
SMOKY SUNSHINE WITH CAP IN PLACE. TEMPERATURES SHADED TOWARD BIAS
CORRECTED VALUES...WHICH IS GENERALLY LOWER THAN OBJECTIVE
GUIDANCE.

TONIGHT...TROUGH DEVELOPS FROM MT INTO WESTERN NE. WEAK LOW DEVELOPS
ALONG TROUGH AS IT MOVES INTO CENTRAL SD BY 12Z MONDAY. CAP SHOULD
BE SUFFICIENT TO KEEP TSRA AT BAY...BUT THERE IS A SLIGHT HINT THAT
ELEVATED TSRA MAY BRUSH FAR NORTHWEST SD LATE. WILL KEEP POPS IN THE
UNMENTIONABLE CATEGORY FOR NOW GIVEN LACK OF CLEAR TRIGGER.
TEMPERATURES WILL BE BALMY.

MONDAY...AFOREMENTIONED LOW SPINS INTO SOUTHWEST MN DROPPING WEAK
COOL FRONT SOUTH THROUGH CWA. POST FRONTAL TSRA POSSIBLE GIVEN
SHORTWAVE ENERGY OVER-TOPPING RIDGE AND WEAKENING MLCIN DUE TO
850-700MB THERMAL PROFILE COOLING OFF BEHIND FRONT. SHEAR WILL BE
SUFFICIENT FOR ISOLATED SEVERE TSRA...PARTICULARLY FROM K2WX INTO
CENTRAL SD. TEMPERATURES WILL BE INFLUENCED BY VERY WEAK COLD AIR
ADVECTION BEHIND THE FRONT AND MID/HIGH CLOUDS ASSOCIATED WITH
SHORTWAVE.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 228 AM MDT SUN JUL 20 2014

UPPER LEVEL RIDGE WILL DOMINATE THE WEATHER PATTERN FOR THE FIRST
PART OF THE WEEK...WITH A STRONG UPPER SHORTWAVE FLATTENING THE
RIDGE A BIT FOR THE SECOND HALF OF THE WEEK. WEAK SHORTWAVE ENERGY
TOPPING THE RIDGE WILL KEEP ISOLATED THUNDERSTORM CHANCES IN THE
FORECAST FOR TUESDAY THROUGH FRIDAY. TEMPERATURES WILL BE AT OR
SLIGHTLY ABOVE AVERAGE FOR MUCH OF THE UPCOMING WEEK...WITH A SLIGHT
COOL DOWN FOR FRIDAY INTO THE WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1119 AM MDT SUN JUL 20 2014

MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.
SOME HAZE FROM THE WRN US WILDFIRES WILL REDUCE VSBYS TO 5-6 MILES
OVER PARTS OF THE AREA. IN ADDITION...VERY SMALL PROBABILITIES
EXIST FOR IFR CIGS WITH STRATUS REDEVELOPMENT AFTER 09Z OVER CNTRL
TO SCNTRL SD.

&&

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

&&

$$

SHORT TERM...HELGESON
LONG TERM...15
AVIATION...BUNKERS





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