450  
FXUS63 KABR 201105 AAA  
AFDABR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE ABERDEEN SD  
505 AM CST MON NOV 20 2017  
   
UPDATE
 
 
ISSUED AT 455 AM CST MON NOV 20 2017  
 
SEE BELOW FOR AN AVIATION FORECAST DISCUSSION FOR THE 12Z TAFS.  
 

 
   
SHORT TERM
 
(TODAY THROUGH WEDNESDAY AFTERNOON)  
ISSUED AT 327 AM CST MON NOV 20 2017  
 
LOW PRESSURE CURRENTLY ACROSS SOUTHERN SASKATCHEWAN WILL SHIFT TO  
SOUTHERN MANITOBA THIS AFTERNOON, AND EXIT ACROSS SOUTHERN ONTARIO  
THIS EVENING. CLOUD COVER REMAINS TRICKY EARLY THIS MORNING, WITH  
THIN HIGH CLOUDS STREAMING IN FROM THE NORTHWEST. THICKER CLOUDS  
WERE EVIDENT OVER EASTERN MT/WY, WHICH WILL IMPACT OUR WESTERN  
COUNTIES CLOSER TO 00Z. TEMPERATURES WILL BE AROUND 20 DEGREES ABOVE  
NORMAL FOR THIS TIME OF YEAR, TOPPING OUT IN THE MID 50S TO LOW 60S  
TODAY. RELATIVE HUMIDITY VALUES WILL FALL TO 20 TO 30 PERCENT.  
COMBINED WITH 10 TO 15 MPH WINDS OUT OF THE WEST, THE DRY AND WARM  
CONDITIONS WILL RESULT IN ELEVATED GRASSLAND FIRE DANGER OVER  
PORTIONS OF CENTRAL SOUTH DAKOTA.  
 
A STRONG COLD FRONT WILL DROP SOUTH THROUGH THE AREA THIS EVENING  
(SINKING SOUTH OF THE ND/SD BORDER ALREADY PRIOR TO 00Z). BEHIND THE  
FRONT, EXPECT BREEZY NORTHWEST WINDS AND COOLER AIR. HIGHS TUESDAY  
WILL ONLY BE IN THE 20S TO AROUND 30 DEGREES. WINDS WILL BE OUT OF  
THE NORTHWEST GUSTING 25 TO 35 MPH, STRONGEST OVER EASTERN SOUTH  
DAKOTA AND WESTERN MINNESOTA AS THE PRESSURE GRADIENT TIGHTENS  
BETWEEN THE EXITING SFC LOW AND WESTERN CANADIAN HIGH PRESSURE  
BUILDING OVERHEAD. THE SFC HIGH SHOULD STRETCH FROM SOUTHERN  
SASKATCHEWAN THROUGH ND AND EASTERN SD BY 00Z WEDNESDAY. THE RESULT  
WILL BE QUICKLY DIMINISHING WINDS LATE TUESDAY AFTERNOON. THE COLD  
SNAP WILL BE BRIEF, WITH ANOTHER WARM UP IN STORE FOR THE SECOND  
HALF OF THE WORK WEEK. THE SFC HIGH WILL SINK ACROSS EASTERN NE/KS  
ALREADY BY 06Z WEDNESDAY, WITH A RIDGE REMAINING OVER OUR FORECAST  
AREA. THE RIDGE WILL SWING INTO MN BY 12Z WEDNESDAY, SETTING THE  
STAGE FOR INCREASING SOUTHERLY FLOW. TEMPERATURES OVER  
STANLEY/JONES/LYMAN COUNTIES SHOULD GET INTO THE MID-UPPER 50S. IT  
WILL BE AN IMPRESSIVE TEMPERATURE GRADIENT, WITH HIGHS ONLY IN THE  
LOW 30S OVER NORTHEASTERN SD/WESTERN MN. STILL KEEPING THE SLIGHT  
CHANCE/LOW CHANCE POPS FOR OUR NORTHEASTERN COUNTIES WEDNESDAY  
AFTERNOON. WHILE MOST MODELS DO SHOW SOME SORT OF PRECIPITATION, IT  
ALL LOOKS TO BE LIGHT MIX OF MAINLY SNOW, MIXING WITH OR  
CHANGING OVER TO RAIN AND/OR DRIZZLE.  
   
LONG TERM
 
(WEDNESDAY EVENING THROUGH SUNDAY)  
ISSUED AT 327 AM CST MON NOV 20 2017  
 
NORTHWEST FLOW ALOFT AND A DRY FORECAST PREDOMINATES THE PERIOD.  
BRIEFLY FRIDAY MORNING, THE FLOW FLATTENS AS ENERGY DIVING SOUTH-  
SOUTHEAST OUT OF CANADA HEADING FOR THE GREAT LAKES REGION KNOCKS  
DOWN THE WESTERN CONUS UPPER-LEVEL RIDGE. PREVIOUSLY, MODELS WERE  
ACTUALLY GENERATING A LITTLE BIT OF LIGHT QPF WITH THIS FEATURE.  
THIS MORNING, THEY DEPICT THIS SYSTEM AS WORKING THROUGH THE REGION  
BASICALLY DRY. BY FRIDAY EVENING, THE HEIGHTS ALOFT ARE RISING OUT  
WEST AGAIN. NOTABLY WARM AIR IS STILL TRYING TO WORK OVER INTO THE  
NORTHEASTERN CORNER OF THE FORECAST AREA AT THE START OF THE PERIOD.  
MODELS/ENSEMBLES STILL DEPICT MUCH ABOVE NORMAL WARM AIRMASS IN  
PLACE HEADING INTO FRIDAY WHEN THE NEXT COLD FROPA IS PROGGED FOR  
THIS CWA, SIGNALING A PENDULUM SWING BACK INTO SOME COLDER AIR OVER  
THE WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 455 AM CST MON NOV 20 2017  
 
GOOD VFR IS EXPECTED OVER THE NEXT 18 HOURS. THERE'S A SMALL  
CHANCE OF STRATUS MOVING SOUTH INTO THE REGION BY TUESDAY MORNING.  
 

 
   
ABR WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
MN...NONE.  

 
 

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