Area Forecast Discussion
Issued by NWS Rapid City, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KUNR 051429
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
829 AM MDT SAT SEP 5 2015

.UPDATE...
ISSUED AT 826 AM MDT SAT SEP 5 2015

14Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHWEST MN TO THE
MT/WY BORDER WITH A LOW NEAR KPIR WITH TROUGH INTO EASTERN CO.
SHORTWAVE ENERGY OVER SOUTHWEST SD/EASTERN WY SUPPORTING BAND OF
-SHRA/ISOLATED -TSRA OVER EASTERN REACHES OF THE CWA. OVERNIGHT
AND NEW GUIDANCE IN GOOD AGREEMENT ON TAKING MAJORITY OF THIS
ACTIVITY OUT OF THE CWA BY EARLY AFTERNOON. ATTENTION THEN TURNS
TO UPPER TROUGH/LOW OVER ID/WA/OR. LIKELY TO BE A LARGE DRY SLOT
WITH THIS SYSTEM...WITH BEST CHANCES FOR TSRA WEST/NORTH OF CWA
LATE THIS AFTERNOON/TONIGHT.

FORECAST UPDATED TO ACCOUNT FOR LATEST TRENDS/TIMING.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 238 AM MDT SAT SEP 5 2015

LEAD IMPULSE IN THE PROCESS OF TRAVERSING THE FA...SUPPORTING SCT
SHRA/ISOLD TS ACROSS PORTIONS OF THE FA. THIS SYSTEM WILL SHIFT
QUICKLY NE THIS MORNING AS THE STRONGER/DEEPER PAC NW UPPER TROUGH
EJECTS INTO THE NORTHERN PLAINS...SUPPORTING PRESSURE FALLS AND
HANGING UP THE LEE SIDE SFC CYCLONE OVER THE REGION. POS THETA-E
ADV REGIME THIS MORNING WILL SUPPORT AN ADVANCING AREA OF SHRA/TS
ACROSS THE SD PLAINS...WITH THE BEST CHANCES FOR COVERAGE OVER
SCENTRAL SD THIS MORNING. WAKE SUBSIDENCE WILL QUICKLY SPREAD OVER
THE REGION THIS AFTERNOON...WITH DRY CONDS EXPECTED MOST
PLACES...SAVE PERHAPS AN ISOLD TS AROUND TRIPP COUNTY. WARM CONDS
EXPECTED TODAY WITH 80S AND 90S FORECAST...ESP OVER THE SW HALF
WHERE SINK SW FLOW WILL BE IN PLACE. ATTENTION THEN TURNS TOWARD
THE ADVANCING PAC NW UPPER TROUGH AND ITS ASSOCIATED POTENT UPPER
JET STREAK. MAIN LOBE OF LSA AND ASSOCIATED UVM WILL REMAIN NW OF
THE FA WITH THIS SYSTEM TONIGHT...WITH THE ASSOCIATED DRY SLOT
REGION OVER NE WY/WESTERN SD. THIS WILL HIGHLY LIMIT PRECIP
CHANCES TO PERHAPS THE FAR NW ZONES WHERE A SHOWER OR STORM MAY
CLIP THIS AREA. THERE WILL ALSO BE A SLIGHT CHANCE FOR SHRA/TS
ACTIVITY ACROSS SCENTRAL SD AFTER MIDNIGHT AS THE LL THETA-E RIDGE
AND ENHANCED LIFT FROM THE RIGHT REAR ENTRANCE REGION OF THE UPPER
JET STREAK WILL ALIGN WITH STEEP MID LEVEL LAPSE RATES. THIS
ACTIVITY MAY LINGER INTO SUNDAY MORNING. LACK OF APPRECIABLE
CAPE/FORCING/SHEAR OVERLAP WILL SUPPORT BENIGN TS ACROSS THE
REGION...WITH PERHAPS A FEW GUSTY WINDS AT MOST. UPPER TROUGH WILL
SHIFT EAST INTO SUN MORNING...WITH A DECENT COLD FRONT EXPECTED
ACROSS THE REGION. A PERIOD OF GUSTY WINDS IS EXPECTED JUST POST
FRONTAL. HOWEVER...LACK OF DEEP LAYER LINKAGE WITH SW FLOW
REMAINING ALOFT WILL SUPPORT A QUICK WANE IN WINDS...WITH FLOW
VEERING E-SE BY EVENING MOST PLACES. MUCH COOLER CONDS EXPECTED
SUNDAY WITH HIGHS IN THE 60S AND 70S. ANOTHER IMPULSE WILL PUSH
INTO THE REGION SUNDAY NIGHT WITH STEEP MID LEVEL LAPSE RATES AND
POS THETA-E ADV POSSIBLY SUPPORTING A FEW SHRA/TS OVER THE
SOUTHERN HALF OF THE FA. DID ADD A LOW POP FOR THIS.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 238 AM MDT SAT SEP 5 2015

SEASONABLE TEMPERATURES CAN BE EXPECTED FOR LABOR DAY
AND THE FIRST HALF OF NEXT WEEK AS ZONAL FLOW ALOFT DEVELOPS ACROSS
THE REGION. WILL KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS
SOUTH CENTRAL SD MONDAY INTO MONDAY NIGHT AS A WEAK DISTURBANCE
PASSES THROUGH MORE FAVORABLE MOISTURE IN PLACE OVER THAT AREA.

A MAINLY DRY COLD FRONT IS PROGGED TO PASS THROUGH THE REGION
SOMETIME ON WEDNESDAY...BRINGING BELOW AVERAGE TEMPS FOR THE LATTER
PART OF THE WEEK. AN UPPER LEVEL DISTURBANCE COULD BRING SOME
SHOWERS TO PORTIONS OF THE AREA ON THURSDAY...ESPECIALLY THE BLACK
HILLS AREA.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 545 AM MDT SAT SEP 5 2015

VFR CONDITIONS GENERALLY EXPECTED ACROSS THE AREA TODAY
INTO TONIGHT. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
CONTINUE ACROSS WESTERN AND SOUTH CENTRAL SD THIS MORNING. BRIEF
MVFR CONDITIONS ARE POSSIBLE WITH ANY HEAVIER SHOWERS. THIS
ACTIVITY SHOULD MOVE EAST OF THE FORECAST AREA BY EARLY AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 238 AM MDT SAT SEP 5 2015

DRY GUSTY SW FLOW WILL DEVELOP TODAY ACROSS THE NORTHEAST WYOMING
PLAINS. SUSTAINED WINDS OF 15 TO 25 MPH WITH HIGHER GUSTS ARE
EXPECTED OVER MUCH OF CAMPBELL AND PORTIONS OF WESTON COUNTIES.
RH/S ARE FORECAST TO DROP TO AROUND 15 PERCENT OVER SOUTHERN
CAMPBELL COUNTY THIS AFTERNOON...SUPPORTING CRITICAL FIRE WEATHER
CONDS WITH THE GUSTY WINDS. HAVE ISSUED A RED FLAG WARNING FOR
THIS. CARRIED THE RED FLAG HEADLINES THROUGH SUNDAY AFTERNOON
GIVEN POOR RH RECOVERY TONIGHT/A FRONTAL PASSAGE/AND VERY DRY
GUSTY SW FLOW EXPECTED ONCE AGAIN SUNDAY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...RED FLAG WARNING FROM NOON TODAY TO 8 PM MDT SUNDAY FOR WYZ259.

&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...26
AVIATION...26
FIRE WEATHER...JC



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.