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000
FXUS63 KABR 291624 AAB
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1024 AM CST FRI NOV 29 2013

.UPDATE...
NO MAJOR CHANGES MADE TO THE FORECAST THIS MORNING. DID DECREASE
CLOUD COVER ACROSS MUCH OF THE AREA AS THE WESTERN HALF OF THE CWA
IS NOW PRETTY MUCH CLEAR...WITH JUST PARTLY CLOUDY SKIES ACROSS
THE EAST. NO CHANGES MADE TO WINDS OR TEMPERATURES AT THIS TIME.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SUNDAY
THE FORECAST CHALLENGE IN THE SHORT TERM WILL BE THREE CLIPPER
SYSTEMS PASSING THROUGH THE REGION.

THE FIRST CLIPPER SYSTEM AND SURFACE TROUGH WILL PASS THROUGH THE
REGION TODAY. THERE IS FAIRLY WARM TEMPERATURES ALOFT...ESPECIALLY
FOR THE SW PORTION OF THE CWA WHERE 850 MB TEMPS PUSH 5C. WITH
THIS CLIPPER SYSTEM PASSING THROUGH...THESE WARM TEMPS SHOULD
PUSH HIGHS INTO THE MID 40S OVER THE SW CWA.

ANOTHER...VERY WEAK CLIPPER SYSTEM WILL PASS THROUGH THE REGION ON
SATURDAY. THIS SYSTEM WILL BRING INCREASING MID LEVEL CLOUDINESS
AND PERHAPS SLIGHTLY COOLER TEMPERATURES THAN PREVIOUSLY EXPECTED.
A BLEND OF THE ECMWF/ADJMAV/ADJMET DOES SUGGEST HIGHS IN THE NE
PORTION OF THE CWA WILL BE SOME 3 TO 5 DEGREES COOLER....THUS HAVE
MADE A SLIGHT ADJUSTMENT FOR THIS LOCATION.

A STRONGER CLIPPER SYSTEM WILL TRACK ACROSS THE REGION ON SUNDAY.
THIS SYSTEM WILL HAVE THE POTENTIAL TO BRING LIGHT PRECIPITATION
INTO THE NORTHERN PORTION OF THE CWA. WHILE ALL MODELS SHOW A
NORTH/SOUTH BAND OF PCPN MOVING ACROSS THE DAKOTAS...THEY DIFFER
ON TIMING AND PLACEMENT OF THE BEST PCPN CHANCES. THE ECMWF/GEM
SHOW ONLY A GLANCING BLOW WITH PCPN CHANCES BEST ALONG AND NORTH
OF HIGHWAY 12. THE GFS/NAM SUGGEST PCPN COULD BE POSSIBLE AS FAR
SOUTH AS HIGHWAY 14. HOWEVER AFTER LOOKING AT GFS BUFFER
SOUNDINGS...THERE IS A FAIRLY SIGNIFICANT DRY LAYER TO OVERCOME
BEFORE PCPN CAN ACTUALLY REACH THE GROUND. OVERALL THIS LOOKS LIKE
A HIGH POP/LOW QPF EVENT. THERMAL PROFILES SUGGEST THE LEADING
EDGE OF PCPN WILL BE ALL SNOW...WITH A TRANSITION OVER TO RAIN AS
WARMER FILTERS INTO THE REGION.


.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
MODELS ARE STILL HAVING TROUBLE LATCHING ONTO A SOLUTION
CONCERNING TIMING AND THE DEGREE OF INTENSITY OF AN ARCTIC SURGE
THAT WILL TAKE PLACE NEAR THE END OF THE EXTENDED PERIOD. PRIOR TO
THIS SHIFT IN THE PATTERN...WILL SEE GENERALLY ZONAL FLOW/BROAD
TROUGHING ACROSS THE CONUS. A WEAK SHORTWAVE EMBEDDED WITHIN THIS
FLOW WILL INDUCE SOME WARM ADVECTION PRECIPITATION/CLOUD COVER TO
START THE PERIOD OFF. THERMAL PROFILES DURING THIS TIME WILL SHIFT
FROM SNOW TO A RAIN/SNOW MIX THANKS TO LOW LEVEL WARM ADVECTION.
AS A TROUGH MOVES OVER THE INTER-MOUNTAIN WEST...FLOW ALOFT
BECOMES MORE SOUTHWESTERLY AND WE WILL SEE SOME MID LEVEL
MOISTURE AND POTENTIALLY SOME LIGHT QPF THOUGH THE LOWER
ATMOSPHERE IS GENERALLY DRY AND H85 TEMPERATURES CLOSE TO AVERAGE.
MODELS DIVERGE IN THE HANDLING OF THE TROUGH AS IT PUSHES OUT OF
THE ROCKIES MID WEEK. PREVIOUS FORECAST ELUDED TO THE GFS BEING
THE MORE AGGRESSIVE OF THE TWO EXTENDED RANGE DETERMINISTIC
MODELS...HOWEVER THE ECMWF NOW HAS A STRONGER LOW MOVING ACROSS
THE REGION WEDNESDAY/THURSDAY. THUS...THE ECMWF DRAWS A 2 TO 3
STANDARD DEVIATION BELOW CLIMO AIRMASS AT H85 INTO THE CWA WHILE
THE GFS IS SLOWER WITH THE CORE OF COLDEST AIR PASSING MAINLY
NORTH OF THE CWA.


&&

.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS EXPECTED THOUGH THE TAF PERIOD. WINDS WILL BE OUT
OF THE SOUTH TODAY...SHIFTING TOWARDS WEST/NORTHWEST THIS
EVENING/OVERNIGHT.


&&

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

$$
UPDATE...PARKIN
SHORT TERM...SD
LONG TERM...CONNELLY
AVIATION...CONNELLY

WEATHER.GOV/ABERDEEN