Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 202343 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
543 PM CST SAT DEC 20 2014

.UPDATE...
DROPPED OVERNIGHT LOWS NEAR PIERRE A COUPLE OF DEGREES. OTHERWISE
FORECAST APPEARS TO BE ON TRACK AND NO FURTHER CHANGES ARE PLANNED.

SEE UPDATED AVIATION DISCUSSION BELOW.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT

LOW CLOUDS AND FOG WILL ONCE AGAIN BE THE RULE OVERNIGHT AS A VERY
MOIST LOW LEVEL AIR MASS REMAINS IN PLACE. BEEN CLOSELY FOLLOWING
THE HRRR LOW-LEVEL CLOUD COVER PRODUCT WHICH HAS BEEN DOING AN
AMAZING JOB WITH HANDLING STRATUS DECKS THE PAST SEVERAL EVENTS.
IT BASICALLY SHOWS THE STRATUS CLOUDS REMAINING IN PLACE ALL NIGHT
WITH A SLIGHT WESTWARD PUSH ONCE AGAIN ON ITS WESTERN EDGE. WILL
GO WITH PERSISTENCE FORECAST CONCERNING THE FOG AS IT HAS BEEN
OCCURRING THE PAST FEW NIGHTS UNDERNEATH THE STRATUS...SO NO
REASON WHY IT WONT HAPPEN AGAIN...AND IN FACT WIDESPREAD LIGHT FOG
IS ALREADY IN PLACE...WITH LOCALLY THICKER FOG. SEEMS THE MOIST
LAYER IS TOO SHALLOW FOR ANY MEANINGFUL FREEZING DRIZZLE TO OCCUR
OVERNIGHT BUT SOMETHING TO KEEP AN EYE ON ANYWAY.

ON SUNDAY...EXPECTING LOW CLOUDS TO HANG IN TOUGH ACROSS THE EAST
ONCE AGAIN WITH NO REAL SIGNALS FROM ANYTHING TO CLEAR THEM OUT.
WILL ALSO BE WATCHING ARRIVAL OF THE LOW PRESSURE SYSTEM WHICH
WILL ENTER THE DAKOTAS BY SUNDAY EVENING...THEN MOVE INTO WESTERN
MINNESOTA AND IOWA REGION BY MONDAY NIGHT. MODELS STILL HAVING A
TOUGH TIME HANDLING THIS SYSTEM IN REGARDS TO STRENGTH MAINLY.
THEY REALLY DO NOT KNOW HOW TO HANDLE THE EVENTUAL CLOSING OFF AND
SUBSEQUENT MOVEMENT OF THE UPPER LOW...AND ITS ASSOCIATED MOISTURE
AVAILABILITY. THIS WILL BE KEY IN FIGURING OUT JUST HOW MUCH WRAP
AROUND PRECIPITATION WE RECEIVE. BASICALLY TOOK A BLENDED APPROACH
FOR RIGHT NOW WHICH STILL LEAVES THE AREA WITH A COUPLE INCHES OF
SNOW AND SOME MIXED PRECIP IN THE FORM OF FREEZING RAIN AND SLEET
TO START THINGS OFF SUNDAY EVENING. THERMAL PROFILES EVENTUALLY
GET COLD ENOUGH BY MONDAY TO CHANGE THINGS OVER TO SNOW. STILL
HAVE MANY DOUBTS AND LOW CONFIDENCE IN EXACTLY JUST HOW THIS
SYSTEM WILL EVOLVE AND HOW MUCH MOISTURE WILL REALLY BE ASSOCIATED
WITH IT. HAVE A FEELING MODELS MAY NOT LATCH ON TO A MORE
DEFINITIVE SOLUTION UNTIL SOMETIME SUNDAY.


.LONG TERM...TUESDAY THROUGH SATURDAY
LOW PRESSURE WILL BE EAST OF THE REGION WHEN THE PERIOD STARTS
WITH THE POTENTIAL FOR LINGERING SNOW SHOWERS...MAINLY ACROSS THE
EASTERN PART OF THE CWA THROUGH THE DAY TUESDAY. A DECENT PRESSURE
GRADIENT ACROSS THE AREA MAY RESULT IN BREEZY TO WINDY CONDITIONS
AS WELL. WEAK HIGH PRESSURE THEN MOVES IN WITH DRY CONDITIONS
EXPECTED WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM LOOKS TO TRACK
ACROSS THE CENTRAL PLAINS ON THURSDAY...BUT THE MODELS ARE NOT IN
VERY GOOD AGREEMENT WITH STRENGTH OR TIMING. THE GFS AND ECMWF
AGREE SOMEWHAT ON THE TIMING WITH THE GEM BEING MUCH SLOWER.
HOWEVER...THE GFS BRINGS LITTLE IN THE WAY OF
PRECIPITATION...WHILE THE ECMWF PLASTERS MOST OF THE STATE, FOR
NOW...WILL STICK FAIRLY CLOSE TO THE SUPERBLEND KEEPING SCHC/CHC
POPS MAINLY ACROSS THE SOUTHERN CWA THURSDAY INTO THE DAY FRIDAY.
HIGH PRESSURE WILL MOVE BACK IN AFTER THAT WITH DRY CONDITIONS
FRIDAY NIGHT THROUGH THE DAY SATURDAY.

SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE FOR THE FIRST
HALF OF THE PERIOD...WITH HIGHS MAINLY IN THE MID 20S TO LOWER 30S
TUESDAY...WEDNESDAY AND THURSDAY. COOLER AIR THEN MOVES IN BEHIND
THE STORM SYSTEM...WITH HIGHS IN THE TEENS AND 20S FRIDAY AND
SATURDAY.



&&

.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

IFR CIGS WILL REMAIN FIRMLY IN PLACE ACROSS THE EASTERN HALF OF
THE CWA THROUGH THE TAF PERIOD. UNDER THE LOW CLOUDS...VSBYS WILL
GENERALLY BE MVFR IN FOG THROUGH THIS EVENING...BUT THERE WILL
LIKELY BE PERIODS OF IFR VSBYS AGAIN OVERNIGHT AND INTO EARLY
SUNDAY MORNING...AFFECTING KABR AND KATY. VFR CONDITIONS WILL
PREVAIL ACROSS THE WESTERN HALF OF THE CWA WITH JUST SOME HIGH
CLOUDS STREAMING OVERHEAD.


&&

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

$$
UPDATE...WISE
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...WISE

WEATHER.GOV/ABERDEEN






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