933  
FXUS63 KABR 180532 AAC  
AFDABR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE ABERDEEN SD  
1132 PM CST SAT FEB 17 2018  
   
UPDATE
 
 
ISSUED AT 1121 PM CST SAT FEB 17 2018  
 
SEE BELOW FOR AN AVIATION FORECAST DISCUSSION FOR THE 06Z TAFS.  
 
UPDATE ISSUED AT 853 PM CST SAT FEB 17 2018  
 
AS FAR AS TONIGHT GOES, THE ONLY CHANGES MADE WERE TO  
TEMPERATURES. HAD TO LOWER MIN TEMPS ACROSS THE CWA. MOST  
SIGNIFICANT LOWERING OF TEMPS WAS FOCUSED ACROSS NORTH CENTRAL AND  
NORTHEAST SOUTH DAKOTA WHERE, DESPITE INCREASING/THICKENING CIRRUS  
CLOUD-COVER, THE BOUNDARY LAYER HAS DECOUPLED AND WINDS ARE THE  
LIGHTEST. UPDATES ARE OUT.  
 
UPDATE ISSUED AT 631 PM CST SAT FEB 17 2018  
 
SEE BELOW FOR AN AVIATION FORECAST DISCUSSION FOR THE 00Z TAFS.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SUNDAY)  
ISSUED AT 319 PM CST SAT FEB 17 2018  
 
THE TIGHTER PRESSURE GRADIENT OVERHEAD THIS AFTERNOON WILL WEAKEN  
LATE THIS AFTERNOON/THIS EVENING AS THE RIDGE OF HIGH PRESSURE THAT  
HAS BEEN OVER WESTERN SD GLIDES ACROSS EASTERN SD AND WESTERN MN BY  
00Z SUNDAY. THE LIGHTER WINDS WILL BE SHORT LIVED AS LOW PRESSURE  
NEARS FROM THE WEST AND WE START OF EXPERIENCE INCREASED SOUTHEAST  
WINDS AFTER 06Z BRING GUSTS NEARING 15-20KTS THAT WILL QUICKLY SLIDE  
TO EASTERN SD (MAINLY COTEAU AREA) BY 12Z SUNDAY.  
 
STILL EXPECTING LOWS TO SPIN DOWN INTO THE TEENS, WITH A FEW LOW 20S  
SNEAKING IN MAINLY SOUTHWEST OF PIR. WHILE THE POTENTIAL STILL  
EXISTS FOR LIGHT SNOW (LESS THAN 1IN) AND FREEZING DRIZZLE (AROUND A  
TRACE), THE THREAT HAS SHIFTED MAINLY NORTH OF THE ND/SD BORDER.  
HAVE STILL INCLUDED A MENTION FOR OUR NORTHERN COUNTIES IN THE HWO,  
BUT THE THREAT CONTINUES TO DIMINISH. OTHERWISE FOR SUNDAY, EXPECT A  
MOSTLY CLOUDY SKY WITH TEMPERATURES RANGING FROM THE 20S OVER NORTH  
CENTRAL SD, BEHIND THE EXITING SFC LOW THAT WILL BE SHIFTING FROM  
WESTERN SD AT DAYBREAK TO OUR SOUTHWESTERN COUNTIES AT 15Z, AND TO  
OUR EAST BY 21Z. GIVEN THE LATE ARRIVAL OF THE LOW/COLD FRONT,  
TEMPERATURES COULD STILL RISE INTO THE 40S OVER EAST CENTRAL SD  
SUNDAY AFTERNOON.  
   
LONG TERM
 
(SUNDAY NIGHT THROUGH SATURDAY)  
ISSUED AT 319 PM CST SAT FEB 17 2018  
 
THE MAIN TIME PERIOD OF INTEREST IN THE LONG TERM WILL BE SUNDAY  
NIGHT THROUGH TUESDAY MORNING. THE REGION WILL BE SITUATED BETWEEN  
LOW PRESSURE OVER THE CENTRAL PLAINS AND HIGH PRESSURE TO THE  
NORTHWEST, WITH MUCH OF THE STATE IN THE PRIME AREA FOR ACCUMULATING  
SNOW. THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS, JUST DIFFER  
ON WHERE A COUPLE OF POTENTIAL SNOW BANDS MAY SET AND PRODUCE HIGHER  
AMOUNTS OF SNOW. COLD TEMPERATURES WILL UNFORTUNATELY LIMIT THE  
AMOUNT OF MOISTURE IN THE SNOW TO JUST ONE QUARTER TO ONE HALF INCH  
OR SO. THE SNOW LOOKS TO BEGIN ACROSS THE WESTERN CWA BETWEEN 03Z  
AND 06Z MONDAY, THEN WILL SPREAD EASTWARD AND CONTINUE THROUGH EARLY  
TUESDAY MORNING. CURRENT INDICATIONS ARE THAT THE SOUTHWESTERN AND  
SOUTH CENTRAL PART OF THE CWA WILL SEE THE BEST POTENTIAL FOR HIGHER  
AMOUNTS OF SNOW, GENERALLY IN THE 7 TO 9 INCH RANGE OVER ABOUT A 36  
TO 42 HOUR PERIOD. DUE TO THE PROLONGED NATURE OF THE EVENT, IT DOES  
NOT MEET CRITERIA FOR A WINTER STORM PER SE, BUT WITH THE AMOUNTS  
EXPECTED, WILL GO AHEAD AND ISSUE A WINTER STORM WATCH FOR AREAS  
WHERE AMOUNTS OF 8 INCHES OR MORE LOOK POSSIBLE, WHICH IS MAINLY THE  
FIVE SWRN-MOST COUNTIES.  
 
HIGH PRESSURE MOVES IN ON TUESDAY BRINGING A RETURN TO DRY  
CONDITIONS. MAY SEE A LITTLE LIGHT SNOW ACROSS THE SOUTHEASTERN CWA  
ON FRIDAY AS A SYSTEM TRACKS FROM NORTHERN TEXAS TO THE EASTERN  
GREAT LAKES, THEN ANOTHER HIGH PRESSURE SYSTEM WILL BRING DRY  
CONDITIONS ON SATURDAY.  
 
BELOW NORMAL TEMPERATURES WILL BE THE RULE DURING THE FIRST HALF OF  
THE PERIOD, WITH HIGHS IN THE SINGLE DIGITS AND LOWER TEENS MONDAY,  
TUESDAY AND WEDNESDAY. THE LATTER HALF OF THE PERIOD WILL SEE A  
RETURN TO NEAR TO ABOVE NORMAL TEMPERATURES, WITH HIGHS IN THE MID  
20S TO LOWER 30S THURSDAY, FRIDAY AND SATURDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)  
ISSUED AT 1121 PM CST SAT FEB 17 2018  
 
SOME LOW LEVEL WIND SHEAR IS IMMINENT OR STILL EXPECTED THROUGH  
MORNING, ESPECIALLY AT KABR, KATY AND KPIR. ALSO BY MORNING, SOME  
LIGHT SNOW OR A MIX OF LIGHT SNOW AND LIGHT FREEZING DRIZZLE MAY  
BE AFFECTING SOME OF THE TERMINALS BRIEFLY AS ANY DEVELOPING  
PRECIPITATION SHOULD BE MOVING OFF TO THE NORTH AND EAST OUT OF  
THE REGION. BY LATE IN THE DAY SUNDAY, SUB-VFR CLOUDS SHOULD BE  
WORKING DOWN INTO ALL FOUR TERMINALS. LIGHT SNOW IS ALSO EXPECTED  
TO BECOME A PREVAILING CONDITION AFTER 00Z MONDAY AT KPIR WITH  
SUB-VFR VISBIES ACCOMPANYING IT, IN ADDITION TO SUB-VFR CIGS.  
FURTHER ON INTO SUNDAY NIGHT, EXPECT LIGHT SNOW TO BEGIN SHOWING  
UP IN OTHER TAFS, TOO.  
 

 
   
ABR WATCHES/WARNINGS/ADVISORIES
 
 
SD...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH LATE MONDAY NIGHT  
FOR SDZ033>035-045-048.  
 
MN...NONE.  

 
 

 
 
UPDATE...DORN  
SHORT TERM...KF  
LONG TERM...PARKIN  
AVIATION...DORN  
 
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