Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 250539 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1139 PM CST MON NOV 24 2014

.UPDATE...
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.

HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX GRIDS TONIGHT AFTER
COLLABORATING WITH NORTHERN NEIGHBORS TO INCLUDE SOME PATCHY
FREEZING DRIZZLE MENTION LATE TONIGHT INTO EARLY TUESDAY MORNING.
MODEL SOUNDINGS SUGGESTING THE LEAD WEAK SHORTWAVE WORKING DOWN
TONIGHT MAY INDUCE ENOUGH LIFT/FORCING TO PRODUCE LIGHT
PRECIPITATION /SNOW...IF ICE CAN ACTIVATE OR SUB-FREEZING LIQUID
IF ICE DOES NOT ACTIVATE/...HOWEVER IT`S MORE LIKELY THAT
CONDITIONS WILL REMAIN DRY OVERNIGHT. WITH PATCHY FREEZING DRIZZLE
NOW IN THE FORECAST...WILL MONITOR CONDITIONS TO SEE IF IN FACT
FREEZING DRIZZLE DEVELOPS IN WHICH CASE A HEADLINE MAY HAVE TO BE
CONSIDERED. NO CHANGES TO TEMPS AT THIS TIME.


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

SUNSHINE AND A GREATLY DIMINISHED SNOWPACK ACROSS THE CWA HAS
ALLOWED TEMPS TO CLIMB PAST THEIR FORECAST HIGHS TODAY IN MANY
LOCATIONS. ALSO CONTINUE TO SEE SCT FLURRIES ACROSS THE FAR EAST
UNDER A STRATOCU FIELD THAT IS QUICKLY BEGINNING TO DEPART. FOR
LATER THIS EVENING...WINDS WILL DIMINISH AS WEAK SFC RIDGE AXIS
MOVES IN. INITIALLY...SKIES WILL BE CLEAR THIS EVENING AS WIND
DROPS OFF...SO EXPECTING TEMPS TO FALL SEVERAL DEGREES. AS THE
NIGHT WEARS ON...CLOUDS WILL BE ON THE INCREASE AS 925 MB TEMPS
ALSO WARM. ALTHOUGH...SFC WINDS WILL BE RATHER WEAK SO MAY NOT BE
ABLE TO FULLY REALIZE WARMER TEMPS AT THE SFC. THAT SAID...THE
INCREASE IN CLOUDS AND OVERALL WARMER AIR MASS MOVING
IN...COMBINED WITH A LACK OF SIGNIFICANT SNOW COVER MAKES
OVERNIGHT LOWS A CHALLENGE. EXPECTING MAINLY SINGLE DIGITS AND
TEENS ACROSS THE CWA...WITH THE COLDEST READINGS OVER THE EASTERN
CWA WHERE SKIES WILL STAY CLEAR THE LONGEST. THE AFOREMENTIONED
INCREASE IN CLOUDS IS ACTUALLY ASSOCIATED WITH A VERY WEAK SYSTEM
SLIDING ACROSS THE DAKOTAS OVERNIGHT. SOME HI RES MODELS
INDICATING A FEW ECHOES DRIFTING ACROSS THE AREA BUT OVERALL THIS
SHOULD BE A NON ISSUE AND CONFINED TO FLURRIES AT BEST. LEFT IN
SOME SLIGHT CHANCE POPS CARRIED OVER FROM PREVIOUS FORECAST.

MAIN ISSUE IN THE SHORT TERM IS THE LOW PRESSURE SYSTEM THAT
SLIDES SOUTHEAST ACROSS THE DAKOTAS TUESDAY INTO TUESDAY NIGHT.
MODELS HAVE FINALLY COME INTO AGREEMENT ON A STORM TRACK...WHICH
BASICALLY TAKES IT RIGHT THROUGH SOUTH DAKOTA. THIS IS WHAT THE
GFS/NAM HAVE ACTUALLY BEEN SHOWING FOR DAYS NOW AND IT WAS THE
EC/GEM SOLUTIONS THAT BACKED WESTWARD TO MATCH UP. THIS PUTS THE
SWATH OF HEAVIEST SNOW OVER THE EASTERN AND NORTHERN PORTIONS OF
THE CWA. BY SAYING HEAVIEST...OVERALL SNOW AMOUNTS ARE STILL
EXPECTED TO BE LIGHT...WITH GENERALLY 1 TO 2 INCHES EXPECTED. WILL
NOT BE SURPRISED TO SEE LOCALLY HIGHER AMOUNTS NEAR 3 IN THE
SISSETON HILLS REGION WITH UPSLOPE ENHANCEMENT POSSIBLE. WINDS DO
NOT APPEAR TO BE A HUGE FACTOR WITH THIS SYSTEM...BUT WINDS WILL
TURN BREEZY NONETHELESS TUESDAY EVENING. GIVEN THE CONFIGURATION
OF THE LOW TRACK...THE STRONGEST WINDS WILL ACTUALLY OCCUR WHERE
THE LEAST SNOWFALL IS EXPECTED. BUT EVEN ACROSS THE EAST WHERE THE
MOST SNOW IS FORECAST...BREEZY/GUSTY WINDS WILL DEVELOP LATER
TUESDAY NIGHT...WHICH WILL LIKELY BLOW ANY FRESHLY FALLEN SNOW
AROUND AND COULD POTENTIALLY CONTRIBUTE TO SOME LOWERED VSBY
ACROSS THE REGION INTO WEDNESDAY MORNING.


.LONG TERM...WEDNESDAY THROUGH MONDAY
COLD AIR WILL BE ADVECTING INTO THE REGION ON WEDNESDAY...ALLOWING
HIGH TEMPERATURES TO TOP OUT EARLY...THEN REMAIN STEADY OR SLOWLY
FALLING THROUGH THE DAY. MEANWHILE...A BROAD AREA OF LOW PRESSURE
WILL DEVELOP OUT OF THE NORTHERN ROCKIES AND EXTEND INTO THE
WESTERN DAKOTAS. LIGHT SNOW IS POSSIBLE ALONG THE BAROCLINIC
ZONE...WHICH COULD CLIP OUR WESTERN CWA. MODELS DO SEEM TO BE
TRENDING SLIGHTLY FURTHER WEST WITH THIS FEATURE HOWEVER.

WEAK UPPER LEVEL ENERGY WILL THEN MOVE ACROSS THE NORTHERN PLAINS
THURSDAY INTO FRIDAY. FOR THE MOST PART IT LOOKS LIKE
PRECIPITATION WILL REMAIN MAINLY IN NORTH DAKOTA...HOWEVER THE
NORTHERN AND NORTHEAST CWA COULD GET CLIPPED. STRONG MID LEVEL
WARM AIR ADVECTION LOOKS TO BE ONGOING AT THIS TIME AS
WELL...ALTHOUGH THE GFS LOOKS TO BE WARMER THAN THE ECMWF
INITIALLY. LEFT ONLY A MENTION OF LIGHT SNOW SHOWERS IN THE
FORECAST...BUT WITH THE WARM AIR PUSH...WILL HAVE TO KEEP AN EYE
ON THE POSSIBILITY OF MIXED PRECIP. BY FRIDAY AFTERNOON...925 MB
TEMPERATURES RANGE FROM THE SINGLE DIGITS BELOW ZERO ACROSS THE
NORTHEAST CWA...TO NEAR 10 C ACROSS THE SOUTHWEST CWA...AND
WOULDNT BE SURPRISED TO SEE THE FORECAST TREND EVEN WARMER WITH
SUBSEQUENT MODEL RUNS.

PROGRESSIVE ZONAL FLOW TAKES OVER FOR THE REMAINDER OF THE LONG
TERM PERIOD...HOWEVER MODELS SHOW VERY LITTLE CONSISTENCY IN THESE
LAST FEW PERIOD. IT DOES APPEAR ANOTHER SHOT OF COLD AIR IS LIKELY
FOR THE SUNDAY AND MONDAY TIME FRAME.


&&

.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

LATE TONIGHT BKN/OVC LOWER CLOUDS /APPX 1000FT AGL TO 3000FT AGL/
WILL MOVE INTO THE REGION FROM THE NORTHWEST. THERE IS A RATHER
LOW PROBABILITY POTENTIAL FOR SOME LIGHT SNOW OR FREEZING DRIZZLE
OVER THE NEXT SEVERAL HOURS. WILL MONITOR UPSTREAM OBS TO SEE IF
ANY LIGHT SNOW AND/OR LIGHT FREEZING DRIZZLE WILL MATERIALIZE AT
OR NEAR THE KMBG/KABR/KATY TERMINALS...MAINLY BETWEEN 09Z AND 15Z
TUESDAY. LATER ON DURING THE DAY TUESDAY...A CLIPPER LOW PRESSURE
SYSTEM WILL BEGIN TO DESCEND UPON THE REGION...INTRODUCING BETTER
CHANCES FOR LIGHT SNOW MOSTLY OVER THE KMBG/KABR/KATY TERMINALS
AND A BRIEF PERIOD OF LIGHT RAIN AT KPIR. ALSO...WATCH OUT FOR
STRONG NORTHWEST WINDS TO PICK UP AT KMBG AND KPIR TOWARD THE END
OF THE TAF VALID PERIOD.


&&

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

$$
UPDATE...DORN
SHORT TERM...TMT
LONG TERM...SERR
AVIATION...DORN

WEATHER.GOV/ABERDEEN




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