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Displaying AFOS PIL: AFDFSD Product Timestamp: 2013-10-24 01:56 UTC
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520 FXUS63 KFSD 240156 AFDFSD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 856 PM CDT WED OCT 23 2013 .UPDATE... ISSUED AT 856 PM CDT WED OCT 23 2013 A FEW FAIRLY MINOR UPDATES THIS EVENING. FAIRLY COMPACT PV ANOMALY IS DRIVING SOUTHEAST FROM EASTERN ND INTO WESTERN MN AT CURRENT TIME...WITH A FEW SPRINKLES OR FLURRIES ACROSS EXTREME NORTHEAST SOUTH DAKOTA. EXTENDED THIS AREA INTO THE FAR NORTHERN CWA FROM AROUND KBKX EASTWARD BY 02Z...AND CONTINUING THROUGH SW MN THROUGH 06Z BEFORE WAVE MOVES OFF TO THE EAST. A FAIRLY SIZABLE GAP IN CLOUDS HAS OPENED ACROSS THE WESTERN AND CENTRAL CWA AS WELL...BUT MORE CLOUDS ROTATING SOUTHWARD BEHIND VORT LOBE AND WILL CREATE A NON STANDARD TEMPERATURE TRACE FOR THE NIGHT. ENOUGH GRADIENT OVERNIGHT AND CLOUDS LINGERING LONG ENOUGH THAT WILL LIKELY IMPACT THE DEGREE TO WHICH ANY FOG MIGHT DEVELOP... ADDING IN FACT THAT WILL SEE CONTINUED FILTERING OF LOW LEVEL DRY AIR /PER KABR 00Z SOUNDING/. FOR NOW...HAVE LIMITED MENTION TO EARLIER CLEARING AREAS NEAR WESTERN MISSOURI RIVER...AS WELL AS THE CONVERGENT AREAS TOWARD THE NORTHEAST GLACIAL HILLS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 323 PM CDT WED OCT 23 2013 UPPER QG FORCING IS EXITING RAPIDLY ACROSS OUR SOUTHERN ZONES AT THIS TIME...COUPLED WITH A WANING OF LOW LEVEL FRONTOGENESIS. THEREFORE A DRIER AIR MASS IS MOVING FROM NORTH TO SOUTH RAPIDLY SHUTTING OFF THE PRECIPITATION. WILL NOT LINGER ANY POPS FROM 00Z ONWARD TONIGHT...AND WILL HAVE A GRADUAL DECREASE IN CLOUDS. THERE IS A CLEAR AREA IN WESTERN SASKATCHEWAN AND EASTERN MANITOBA...WHICH THE HUMIDITY FIELDS NEAR 850-800MB IN THE NAM PICKED UP ON. SO THIS LAYER WAS FOLLOWED FOR AN OVERALL CLOUD COVER TREND BOTH TONIGHT AND THURSDAY. AS SKIES CLEAR WITH A LIGHT DRY WIND...FAVORED THE COLD CONSENSUS MOS GUIDANCE THE MOST. WITH SMALL DEW POINT DEPRESSIONS... WILL THROW IN SOME FOG CHANCES FOR MUCH OF THE FORECAST AREA TONIGHT WHERE THE WIND SPEEDS ARE GENERALLY LESS THAN 8 MPH OR SO. THE NAM HUMIDITY TIME SECTIONS INCREASE THE MOISTURE IN THE 850-800MB LAYER THURSDAY AFTERNOON IN THE EASTERN SECTIONS OF EAST CENTRAL SD...PARTS OF SOUTHEAST SD...SOUTHWEST MN AND THE NORTHERN PARTS OF NORTHWEST IA. THIS IS LIKELY STRATOCU DEVELOPMENT PARTIALLY DUE TO CHILLY TEMPERATURES ALOFT. SO KEPT THE PREVIOUS FORECASTS TREND OF PARTLY SUNNY SKIES IN THE AFTERNOON HOURS IN THOSE AREAS. ELSEWHERE SKIES SHOULD BE MOSTLY SUNNY TO SUNNY. MIXING WILL ALLOW HIGHS TO REACH MAINLY THE MID 40S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 323 PM CDT WED OCT 23 2013 DRY PATTERN CONTINUES ACROSS THE REGION THROUGH THE UPCOMING WEEKEND. RIDGING OVER THE INTERMOUNTAIN WEST NUDGES EASTWARD ON FRIDAY OVER THE HIGH PLAINS...WHILE RETURN FLOW BRINGS ABOUT BREEZY SOUTHWESTERLY WINDS. WITH MOSTLY SUNNY TO PARTLY CLOUDY SKIES AND SOME WARM AIR ADVECTION...HIGHS WILL BE MUCH CLOSER TO SEASONAL NORMALS IN THE 50S AND COULD EVEN REACH THE LOWER 60S IN SOUTH CENTRAL SD. A COLD FRONT TRACKS THROUGH THE REGION ON FRIDAY NIGHT...SHIFTING BREEZY WINDS BACK TO THE NORTHWEST THROUGH SATURDAY...BUT FRONTAL PASSAGE LOOKS TO BE DRY AT THIS POINT AND LACKS MUCH OF ANY COLD AIR PUSH. WINDS WILL HOLD LOWS UP IN THE 30S FRIDAY NIGHT WHILE SATURDAY HIGHS COOL OFF A LITTLE BIT INTO THE MID 40S TO MID 50S. A MUCH MORE SIGNIFICANT PATTERN CHANGE SHOWS UP LATE THIS WEEKEND. THE RIDGE QUICKLY BREAKS DOWN AS A TROUGH DIGS INTO THE PACIFIC NORTHWEST ON SUNDAY. SOUTHWESTERLY FLOW DEVELOPING AHEAD OF THIS SYSTEM WILL BRING MUCH MILDER TEMPERATURES...BUT IT LOOKS LIKE WINDS COULD BE A LITTLE BREEZY. HIGHS WILL RETURN TO THE 50S TO LOWER 60S. MODELS ARE SLOWING DOWN THIS SYSTEM A BIT...FAVORING A DEEPENING TROUGH OVER THE WESTERN STATES AND DIRTY SOUTHWEST FLOW DEVELOPING OVER THE CENTRAL AND NORTHERN PLAINS MONDAY AND TUESDAY. WITH WEAK IMPULSES POSSIBLY TRACKING THROUGH THE AREA...PRECIPITATION CHANCES ARE EXPECTED DURING THIS PERIOD...BUT THE DETAILS ARE UNCERTAIN. TEMPERATURES ALSO REMAIN TRICKY...BUT WHILE IT LOOKS LIKE PRECIPITATION WILL START OUT AS RAIN ON MONDAY...IT WILL LIKELY TRANSITION TO A MIX OF RAIN/SNOW OR SNOW BY TUESDAY. COULD SEE PRECIPITATION AS EARLY AS MONDAY....BUT POTENTIAL LOOKS A LITTLE BETTER MONDAY NIGHT AND TUESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 652 PM CDT WED OCT 23 2013 EXPECTING VFR CONDITIONS FOR NEXT 24 HOURS. VFR CEILINGS SHOULD SLOWLY DISSIPATE FROM WEST TO EAST...BUT WILL SEE A FEW RANDOM HOLES PUNCHED IN WIDESPREAD OVERCAST AREAS THROUGH THE EVENING. WITH SURFACE GRADIENT REMAINING OVERNIGHT...CONTINUED DRY AIR ADVECTING IN AT LOW LEVELS...AND LIKELIHOOD OF CLOUDS LINGERING SOMEWHAT LONGER... DO NOT FEEL FOG THREAT IS AT A MENTIONABLE LEVEL FOR THIS SET OF TAFS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHAPMAN SHORT TERM...MJ LONG TERM... AVIATION...CHAPMAN