520
FXUS63 KABR 210950
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
350 AM CST SAT NOV 21 2009
SHORT TERM
TODAY THROUGH MONDAY
TODAY WILL BE BREEZY/WINDY ACROSS MUCH OF THE CWA AS PRESSURE
GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. 925/850
WINDS ON THE ORDER OF 40-50 KNOTS BUT DO NOT EXPECT WIND GUSTS TO
BE THIS HIGH. THE COLD FRONT TRACKS EAST ACROSS THE CWA
TONIGHT...BRINGING COOLER TEMPERATURES FOR SUNDAY. AFTER MUCH
ABOVE NORMAL TEMPS IN THE 50S TODAY...HIGHS WILL DROP BACK DOWN
INTO THE 40S FOR SUNDAY. WEAK SHORTWAVE MOVES THROUGH THE AREA ON
SUNDAY BUT BEST MOISTURE AVAILABILITY REMAINS EAST OF THE REGION
IN MN SO WILL KEEP FORECAST DRY. ATTENTION THEN TURNS TO THE
APPROACHING STORM SYSTEM WHICH BEGINS TO AFFECT THE REGION LATE
SUNDAY NIGHT AND MONDAY. GFS REMAINS THE FURTHEST NORTH OF ALL
MODELS AND IS QUICKER...BUT HAS SHOWN A NOTICEABLE TREND TO THE
SOUTH...TRYING TO COME IN LINE MORE WITH THE MORE CONSISTENT EC
AND CANADIAN SOLUTIONS...WHICH HAVE ALWAYS BEEN FURTHER SOUTH. THE
NEW 00Z EC IS EVEN A TAD FURTHER SOUTH THAN ITS PREVIOUS RUN BUT
WHATS INTERESTING IS THAT IT HAS DEVELOPED A MORE PRONOUNCED
INVERTED TROUGH WHICH NOSES NORTHWARD ALONG THE SD/MN BORDER. THIS
COULD SPELL OUT DECENT PRECIP CHANCES THIS FAR NORTH...EVEN THOUGH
MAIN SFC LOW IS WELL SOUTH OF THE AREA. WILL HAVE TO KEEP AN EYE
ON THIS DEVELOPMENT. THERMAL PROFILES STILL SUGGEST MOSTLY RAIN TO
START OFF...THEN CHANGING OVER TO SNOW FROM WEST TO EAST TOWARDS
THE END OF THE EVENT. HAVE NOT MADE REAL SIGNIFICANT CHANGES TO
WX/POPS DURING THE SHORT TERM PERIOD.
LONG TERM
MONDAY NIGHT THROUGH FRIDAY
A SOMEWHAT ACTIVE PATTERN STILL APPEARS ON TAP FOR THE FIRST PART
OF THE LONG TERM. ALL MODELS STILL PRODUCE A DECENT LOOKING YET
PROGRESSIVE UPPER LOW OVER THE CENTRAL/NORTHERN PLAINS THROUGH MID
WEEK. THE ECMWF REMAINS THE SLOWEST AND FURTHEST SOUTH OF ALL
DETERMINISTIC 00Z RUNS. MEANWHILE THE GEM HAS TRENDED TOWARD THE
GFS. WITH SOME UNCERTAINTY IN THE FORECAST...FELT THAT THE BEST
POLICY WAS TO STAY SOMEWHAT CLOSE TO THE INHERITED SOLUTION. RAIN
AND SNOW WILL BE POSSIBLE INTO TUESDAY BEFORE BECOMING MOSTLY SNOW
BY TUESDAY NIGHT. IT APPEARS THE HIGHEST PCPN PROBABILITIES WILL
EXIST OVER THE BIG SIOUX VALLEY/SISSETON HILLS WHERE AN INVERTED
TROF MAY HANG OUT FOR 24 HOURS OR MORE. TEMPERATURES WERE ONLY
MODIFIED SLIGHTLY AFTER LOOKING AT THE LATEST LONG RANGE TEMP PROGS.
AVIATION
THROUGH TODAY VFR CONDITIONS WILL PREVAIL ALTHOUGH BLUSTERY WINDS
WILL ARRIVE SHORTLY AFTER DAYBREAK.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
SHORT TERM...TMT
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
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