703
FXUS63 KUNR 311916
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
116 PM MDT MON MAR 31 2025
KEY MESSAGES
-A SERIES OF DISTURBANCES WILL BRING CHANCES FOR RAIN/SNOW TO THE
REGION THROUGH MUCH OF THE WEEK
-A STRONGER DISTURBANCE WILL BRING A GOOD CHANCE OF RAIN AND SNOW
TO THE REGION TUES, WITH ACCUMULATIONS POSSIBLE TUES NIGHT INTO
WED
-TEMPERATURES TO REMAIN MAINLY BELOW SEASONAL NORMS THROUGH THE
WEEK
DISCUSSION
(THIS EVENING THROUGH MONDAY)
ISSUED AT 115 PM MDT MON MAR 31 2025
POTENT PAC UPPER JET AND ASSOCIATED DEEP NORTHEAST PAC LOW
CONTINUES TO SUPPORT UNSETTLED FLOW, BRINGING A SERIES OF IMPULSES
INTO THE WESTERN CONUS. THIS PATTERN WILL CONTINUE THROUGH THE
WEEK, WITH SEVERAL ROUNDS OF PAC SYSTEMS INTO THE REGION, WITH THE
STRONGEST ONE AFFECTING THE REGION TUE INTO WED. DEEP UPPER
TROUGH IS CURRENTLY MOVING INTO THE WESTERN CONUS, WITH WAA
ENSUING OVER THE REGION. FRONTSIDE IMPULSE WILL ADVECT THROUGH THE
REGION THIS EVENING AND OVERNIGHT, SUPPORTING INCREASING CHANCES
FOR RAIN OVER THE FA, ESP SOUTH CENTRAL TO CENTRAL SD WHERE THE
BEST OVERLAP OF LIFT AND MOISTURE CONVERGENCE WILL BE IN PLACE.
FURTHER NORTH ACROSS NW SD, TEMPS WILL BE COLD ENOUGH FOR SOME
FREEZING RAIN AND OR SNOW AS THERMAL FIELDS WILL BE ON THE BORDER
OF PRECIP TYPES. GIVEN WAA REGIME, NOT EXPECTING ZR TO BE MUCH AN
IN ISSUE ATTM WITH TEMPS HOVERING IN THE LOW 30S OVERNIGHT. THE
MAIN/STRONGER WAVE WILL PUSH OUT OF THE ROCKIES TUE AND SUPPORT A
GOOD CHANCE OF RAIN AND SNOW OVER THE REGION. FORECAST MODELS
STILL VARY ON THE TRACK AND THERMAL FIELDS WHICH INTERN SUPPORTS
VASTLY DIFFERENT SOLUTIONS FOR POTENTIAL SNOW AMOUNTS TUE NIGHT
INTO WED. GIVEN THE PATTERN AND THE EXPECTED TRACK OF THE LOW,
FEEL THE ECMWF, HRRR, AND NAM ALL HAVE GOOD HANDLE ON THE
EVOLUTION OF THIS SYSTEM AND HAVE ADJUSTED THE FORECAST IN THEIR
DIRECTION. THIS WOULD SUGGEST THAT ADV LEVEL SNOW WILL BE POSSIBLE
ACROSS NW SD AND THE NORTHERN BLACK HILLS WHERE SOME UPSLOPE
ENHANCEMENT WILL BE IN PLACE LATE TUE NIGHT INTO WED MORNING.
GIVEN MARGINAL TEMPS WITH SOME OF THE SNOW FALLING DURING THE DAY
AND A LACK OF CONVECTIVE SIGNAL, EXPECT THAT SNOW RATIOS WILL
RANGE FROM 5:1 TO 10:1, OUTSIDE OF THE BLACK HILLS. THIS PUTS 4-8
INCHES IN PARTS OF THE NORTHERN BLACK HILLS, WITH 2-4 INCHES
ACROSS NW SD. DRY AIR WILL QUICKLY WORK INTO THE REGION WED WITH
PRECIP ENDING DURING THE DAY. GUSTY NW WINDS CAN BE EXPECTED ON
THE BACKSIDE OF THE LOW WED, BUT WINDS DO LOOK TO BE BELOW ADV
LEVELS. AFTER WED, THINGS DRY OUT WITH JUST SOME CHANCES FOR
SHOWERS AT TIMES AS SEMI- UNSETTLED WESTERLY FLOW CONTINUES. TEMPS
WILL ALSO MODERATE SOME BY THE END OF THE WEEK, BUT STILL REMAIN
AROUND SEASONAL NORMS. WARMER WEATHER DOES LOOK TO RETURN NEXT
WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1118 AM MDT MON MAR 31 2025
MVFR TO IFR CIGS WILL REMAIN IN PLACE ACROSS MUCH OF THE REGION
THROUGH THE VALID TERMINAL FORECAST PERIOD. THE FIRST IN A SERIES
OF SYSTEMS WILL MOVE THROUGH THIS EVENING AND OVERNIGHT, BRINGING
AREAS OF LIGHT RAIN AND SNOW BACK TO THE REGION. MUCH OF THE PCPN
SHOULD MOVE EAST OF THE AREA BY 15Z TUESDAY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...JC
AVIATION...HINTZ
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page