Issued by NWS Aberdeen, SD
000 FXUS63 KABR 292039 AFDABR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 339 PM CDT SAT AUG 29 2009 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT NOT MUCH GOING ON DURING THE SHORT TERM AS MODELS AND GFS ENSEMBLES SHOW SURFACE HIGH PRESSURE BUILDING EVER SO SLOWLY ACROSS THE REGION AND TO THE SOUTHEAST TONIGHT THROUGH MONDAY NIGHT. THE TCU AND ISOLD SHRAS ACROSS NORTHEAST SD AND WEST CENTRAL MN LATE THIS AFTERNOON WILL DISSIPATE INTO THE EARLY EVENING AS THE RESPONSIBLE SHORT WAVE TROUGH EXITS AND SURFACE HEATING DIMINISHES. THUS...AS SKIES CLEAR AND THE WINDS GO LIGHT LATE THIS EVENING UNDER THE SURFACE HIGH...EXPECT TEMPERATURES TO COOL TO AROUND 40 DEGREES BY MORNING ACROSS THE EASTERN CWA. COULD ALSO BE SOME UPPER 30S. SUNDAY WILL BE SLIGHTLY WARMER ACROSS THE CWA BUT STILL COOLER THAN NORMAL AS WINDS TURN TO THE SOUTHEAST WITH SOME FEW-SCT CU DEVELOPING. THESE SOUTHEAST WINDS WILL SLOWLY INCREASE INTO MONDAY NIGHT AS THE SURFACE PRESSURE GRADIENT TIGHTENS UP AND THE LOW LEVEL WINDS INCREASE. THE TEMPERATURES WILL ALSO BE HIGHER ON MONDAY WITH WAA AND CONTINUED MOSTLY CLEAR SKIES. MONDAY NIGHT WILL HAVE SOME WARM OVERNIGHT LOWS AS WINDS STAY UP. .LONG TERM...TUESDAY THROUGH SATURDAY UNCOMMONLY SIMILAR SOLUTIONS IN MOST ALL EXTENDED MODEL FAMILIES WRT LONGWAVE FLOW PATTERN. STILL DEALING WITH AN APPROACHING CLOSED UPPER CIRCULATION ON TUESDAY...AN UPPER CIRCULATION TUCKED NICELY UNDERNEATH A LARGE BROAD UPPER LEVEL RIDGE WHICH SLOWLY TRANSLATES EASTWARD DURING THE OUT PERIODS. THIS UPPER CIRCULATION IS STILL PROGGED TO WORK ITS WAY OUT ONTO THE SOUTH DAKOTA/NEBRASKA PLAINS BY TUESDAY NIGHT...AND SLOWLY MEANDERING TOWARD SOUTHERN MINNESOTA/IOWA RIGHT ON THROUGH THURSDAY. BY THE END OF THE PERIOD...A WESTERN CONUS LONGWAVE UPPER TROF IS TRYING TO TAKE SHAPE...PLACING SOME IF NOT ALL OF THIS CWA INTO MORE OF A SOUTHWESTERLY FLOW ALOFT BY SATURDAY. CONTINUED SOME POPS MENTION FOR SHOWERS AND THUNDERSTORMS MAINLY FROM TUESDAY THROUGH WEDNESDAY NIGHT FOR SAID UPPER CIRCULATION CENTER WORKING THROUGH. OTHERWISE ONLY SLT CHANCE POPS SHOW BACK UP AGAIN LATE IN THE PERIOD IN RESPONSE TO SWRLY FLOW PATTERN ALOFT...PER COLLABORATION. NO REAL SIGNIFICANT CHANGES MADE TO MAX/MIN TEMPERATURES IN THE OUT PERIODS. THE 925HPA AND 850HPA THERMAL PROGS ALL POINT TO HIGH TEMPERATURES MAINLY IN THE 70S AND 80S THROUGHOUT THE PERIOD...AND NUMERICAL MEX GUIDANCE APPEARS TO SUPPORT THIS. && .AVIATION... VFR DOMINATES THE REGION THIS EVENING THROUGH TOMORROW. ONCE ANY SHORT-LIVED ISOLATED SHOWERS DISSIPATE LATE THIS AFTERNOON/EARLY THIS EVENING...EXPECT SKIES TO CLEAR. NORTHEASTERLY SURFACE WINDS WILL ALSO GRADUALLY SWING AROUND TO MORE OF AN EAST OR SOUTHEASTERLY DIRECTION TOWARD SUNRISE ON SUNDAY. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...MOHR LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
