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Displaying AFOS PIL: AFDUNR Received: 2014-04-15 23:20 UTC
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814 FXUS63 KUNR 152320 AFDUNR AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 520 PM MDT TUE APR 15 2014 .SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT ISSUED AT 108 PM MDT TUE APR 15 2014 THE LATEST WATER VAPOR IMAGES SHOWED A SHORT-WAVE TROUGH MOVING ACROSS THE NWRN CONUS...TOWARD WY. A JET STREAK WAS ROUNDING THE BASE OF THE TROUGH...AND THUS THE TROUGH IS EXPECTED TO INTENSIFY. THIS TROUGH WILL MOVE ACROSS THE FORECAST AREA TONIGHT AND WEDNESDAY MORNING...BRINGING A MIX OF RAIN AND SNOW. FOR THE REST OF THIS AFTERNOON CLOUDS WILL BE INCREASING AND IT WILL REMAIN MILD AS A LOW-LEVEL THERMAL RIDGE IS OVER THE AREA. THE LEADING EDGE OF THE Q-VECTOR CONVERGENCE WILL REACH ERN WY BY 00Z. THIS EVENING THE FAST-MOVING...COMPACT...BUT STRONG TROUGH WILL SPREAD RAIN ACROSS THE NWRN HALF OF THE AREA. LOW-LEVEL THERMAL PROFILES AND SREF/NAM/GFS/RAP MODEL GUIDANCE SUGGESTS THAT BY 06Z SNOW WILL BE OVER THE HIGHEST BLKHLS AND HIGHER TERRAIN OF NERN WY. PRECIPITATION AMOUNTS WILL BE TEMPERED BY THE FAST MOVEMENT OF THE SYSTEM...YET...PRECIP RATES WILL BE ENHANCED BY STEEP LAPSE RATES (NEAR MOIST-NEUTRAL) AND STRONG Q-VECTOR CONVERGENCE AND UPSLOPE FLOW OVER THE NWRN BLKHLS. THIS IS EXPECTED TO BRING 1-3 INCHES OF SNOW FOR THE HIGHEST ELEVATIONS TONIGHT. RAIN WILL MIX WITH SNOW OVER THE WRN SD PLAINS LATE TONIGHT...BUT THE FAST MOVEMENT OF THE TROUGH COMBINED WITH TEMPERATURES IN THE LOWER 30S WILL PRECLUDE SNOWFALL ACCUMULATIONS. AT MOST 1-2 INCHES OF SNOW MAY ACCUMULATE IN THE HIGHER TERRAIN OF THE NERN WY PLAINS. ON WEDNESDAY MORNING THE WAVE AND Q-G FORCING WILL MOVE EAST EARLY AND WILL BE FOLLOWED BY GUSTY NORTHWEST WINDS (850-MB WINDS OF 20-40 KT). STEEP LAPSE RATES...CYCLONIC FLOW ALOFT...AND RESIDUAL MOISTURE OVER THE AREA WILL RESULT IN A CONTINUED CHANCE OF RAIN/SNOW SHOWERS ...WITH SNOW CONFINED MOSTLY TO THE BLKHLS...NERN WY...AND NWRN SD. ON WEDNESDAY NIGHT IT WILL BE MOSTLY DRY...BUT A WEAK SHORT-WAVE TROUGH MAY BRING ADDITIONAL SCATTERED SHOWERS TO THE AREA. && .LONG TERM...THURSDAY THROUGH TUESDAY ISSUED AT 108 PM MDT TUE APR 15 2014 UNSETTLED CONDITIONS WILL CONTINUE ON THURSDAY AS UPPER TROF WORKS THROUGH THE NRN PLAINS...WITH STEEP LAPSE RATES RESULTING IN SCT PCPN FOR THE REGION. TEMP FCST REMAINS TRICKY WITH WARM ADVECTION SETTING IN FOR THE WRN 2/3RDS OF CWFA...AND HAVE UNDERCUT GUIDANCE A BIT GIVEN EXPECTED CLOUD COVER AND PCPN. MUCH WARMER TEMPS THEN EXPECTED FOR FRI AS SHORT WAVE RIDGE CROSSES THE NRN PLAINS. ANOTHER QUICK MOVING DISTURBANCE ROTATES THROUGH FRIDAY NIGHT FOR ANOTHER BRIEF PCPN EVENT...ALTHOUGH TEMPS LOOK TO BE WARM ENOUGH FOR MOSTLY LIQUID. FLAT UPPER RIDGE THEN BUILDS INTO THE PLAINS FOR THE WEEKEND AND EARLY NEXT WEEK...WITH DRY WEATHER AND WARMER TEMPERATURES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 515 PM MDT TUE APR 15 2014 VFR CONDITIONS WILL CONTINUE INTO THIS EVENING. A CDFNT WILL MOVE THROUGH THE AREA TONIGHT. WDSPRD MVFR/IFR CIGS WILL DEVELOP BEHIND THE CDFNT ALONG WITH GUSTY NW WINDS. RAIN WILL ALSO DEVELOP THIS EVENING...CHANGING TO SNOW OVER NERN WY AND THE BLKHLS LATE TONIGHT...WITH A RAIN/SNOW MIX POSSIBLE VERY LATE TONIGHT ON THE SD PLAINS. MVFR/IFR CONDITIONS IN SNOW EXPECTED OVER NERN WY AND THE NRN BLKHLS FROM LATE TONIGHT INTO WED MRNG. MVFR CONDITIONS WILL LIKELY LINGER OVER MUCH OF THE AREA WED IN CAA. CYCLONIC FLOW WITH STEEP LL LAPSE RATES WILL SUPPORT SCT SNOW SHOWERS OVER MUCH OF THE AREA WITH SCT MVFR CONDITIONS...POSSIBLY ISOLD IFR IN HEAVIER SHOWERS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...BUNKERS LONG TERM...JOHNSON AVIATION...JC