Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 180348 AAB
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
948 PM CST WED DEC 17 2014

.UPDATE...
GENERALLY SPEAKING...TEMPERATURES ARE FOLLOWING THE FORECAST TREND
OF COOLER READINGS ON LITTLE TO NO WIND ACROSS THE EASTERN ZONES
UNDER A CLEAR SKY...WITH WARMER READINGS ACROSS THE WESTERN ZONES
WHERE THERE IS SOME WIND AND SKIES ARE OVERCAST. NO NOTE-WORTHY
CHANGES FORTHCOMING TO MIN TEMPS TONIGHT. LOW AND MID CLOUDS ARE
WORKING NORTH AND EAST ACROSS THE CWA AT THIS TIME...AS THE LOW
PRESSURE SYSTEM OVER FAR EASTERN MONTANA CONTINUES TO WORK INTO
THE REGION. HAVE INTRODUCED SOME FLURRIES MENTION ACROSS THE
REGION IN CASE ANY OF THESE LOW-MID LEVEL CLOUDS DEVELOPING IN THE
WEAK LIFT ASSOCIATED WITH THE APPROACHING LOW PRESSURE SYSTEM END
UP WORKING IN TANDEM /SEEDER-FEEDER MECHANISM/ TO PRODUCE A FEW
FLAKES OF SNOW.

SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.


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

STRATUS...WITH A LITTLE SCATTERING OF THE FRONT EDGE..CONTINUES TO
HANG OVER THE MISSOURI RIVER VALLEY THIS AFTERNOON. NO MOVEMENT OF
THE LOW LEVEL MOISTURE PROFILES UNTIL 12Z TO 18Z THURSDAY WHEN
THEY WILL SLOWLY SHIFT EAST AS HIGH PRESSURE EXITS. STILL THERE IS
SOME POTENTIAL FOR CLOUD DEVELOPMENT AS FAR EAST AS ABERDEEN
TONIGHT WHICH MADE FOR A TRICKY TEMPERATURE FORECAST. KEPT LOWS
SIGNIFICANTLY COOLER OVER THE EASTERN CWA WHICH WILL HAVE CLEAR
SKIES THROUGH THE NIGHT.

A WEAK TROF WILL MOVE OVERHEAD THURSDAY. NOT MUCH FORCING WITH
THIS FEATURE AND MOISTURE ALOFT IS LACKING. WILL ALSO SEE WEAK WARM
ADVECTION WHICH WILL PERSIST THROUGH THE REST OF THE PERIOD...SO
MILDER TEMPERATURES CAN BE EXPECTED THURSDAY/FRIDAY. DEPENDING ON
CLOUD COVER...HIGH TEMPS MAY NEED TO BE ADJUSTED AS THEY MAY NOT
REALIZE FULL WARMING POTENTIAL.


.LONG TERM...SATURDAY THROUGH WEDNESDAY
THE LONG TERM PORTION OF THE FORECAST WILL SEE A SIGNIFICANT
PATTERN CHANGE AS THE ARCTIC OSCILLATION BECOMES HIGHLY
POSITIVE...TO NEGATIVE WITHIN THE NEXT 7 TO 10 DAYS. THE PERIOD
BEGINS WITH WEAK UPPER LEVEL DISTURBANCES MOVING ACROSS THE
REGION. THESE WAVES WILL PASS THROUGH DRY WITH ONLY NOTICEABLE WARM
TEMPS EXPECTED DUE TO MIXING WINDS. HIGHS THIS WEEKEND SHOULD
RANGE IN THE 30S AND 40S...OR 5 TO 15 DEGREES ABOVE NORMAL.

A STRONGER SHORT WAVE TRACKING SOUTHEASTWARD ACROSS THE REGION
SUNDAY NIGHT THROUGH MONDAY COULD BECOME A CLOSED LOW OVER THE
MIDWEST. THIS SYSTEM WILL HAVE EXCELLENT UPPER LEVEL JET SUPPORT
WHICH SHOULD CAUSE RAPID INTENSIFICATION. THE ECMWF IS THE
STRONGEST MODEL AND KEEPS THIS SYSTEM NEAR THE CWA THROUGH TUESDAY
NIGHT. THE GEM IS LESS AGGRESSIVE AND SHOWS VERY LITTLE PCPN. THE
GFS IS BETWEEN THESE TWO EXTREMES. BECAUSE OF THE DISAGREEMENT
BETWEEN THE MODELS...WILL MAKE VERY MINOR CHANCES TO THE POP GRIDS
SUNDAY NIGHT THROUGH TUESDAY. REGARDLESS WHICH MODEL USED...A
RETURN IS SEASONAL TEMPERATURES ARE EXPECTED AFTER OUR BRIEF
WEEKEND WARM WEATHER.


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

KPIR...EITHER IFR OR MVFR STRATUS IS EXPECTED TO PERSIST FOR THE
NEXT 24 HOURS.

KMBG...CURRENTLY VFR...BUT THE IFR/MVFR STRATUS JUST OFF TO THE
WEST AND SOUTH IS EXPECTED TO MAKE A PUSH NORTH AND EAST
TONIGHT...AND HAVE SET THE BAR AT 06Z FOR TRANSITION FROM VFR TO
SUB-VFR...PER THE LATEST AVAILABLE RAPID REFRESH MODEL OUTPUT.

KABR/KATY...SHOULD SEE CLEAR SKIES GIVING WAY TO VFR BKN-OVC SKIES
WITHIN THE NEXT 3 TO 6 HOURS. SUB-VFR STRATUS IS CURRENTLY
FORECAST TO WORK INTO THESE TWO TERMINALS BY EARLY AFTERNOON ON
THURSDAY.

ALL FOUR TERMINALS COULD END UP SEEING SOME FLAKES OF SNOW FLYING
LATER TONIGHT AND DURING THE DAY ON THURSDAY WHILE A WEAK AREA OF
LOW PRESSURE MOVES THROUGH THE REGION.


&&

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

$$
UPDATE...DORN
SHORT TERM...WISE
LONG TERM...SD
AVIATION...DORN

WEATHER.GOV/ABERDEEN





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