FXUS63 KABR 020917
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
317 AM CST WED DEC 2 2009

.SHORT TERM...TODAY THROUGH FRIDAY
THE MODELS CONTINUE TO BE CONSISTENT AND AGREE WELL OVER THE NEXT
FEW DAYS. DEEP NORTHERLY FLOW AROUND THE EASTERN CANADIAN UPPER
LOW CENTER WILL CONTINUE TO BRING DOWN A COUPLE SHORT WAVES ALONG
WITH REINFORCING SHOTS OF COLD AIR THROUGH FRIDAY. FOR TODAY AND
TONIGHT...SATELLITE AND MODELS SHOW THE FIRST UPPER LEVEL TROUGH
SPINNING IN SOUTHERN CANADA EARLY THIS MORNING AND HEADING INTO
THE UPPER MIDWEST THROUGH THE DAY. AT THE SURFACE...A COLD FRONT
IN SOUTHERN CANADA WITH THE SECOND PUSH OF COLDER AIR SINCE
YESTERDAY WILL BE FOLLOWING THE UPPER TROUGH THROUGH THE DAY.
THESE WILL BRING IN MORE LOW CLOUDS ALONG WITH SCATTERED SNOW
SHOWERS MAINLY FOR THIS AFTERNOON AND EVENING. BUFKIT SOUNDINGS
WERE SHOWING STEEP LAPSE RATES DEVELOPING UP THROUGH 700MB THIS
AFTERNOON AND EVENING ALONG WITH PLENTY OF MOISTURE. THIS WILL AID
IN THE DEVELOPMENT OF SCATTERED SNOW SHOWERS ACROSS THE CWA. THESE
STEEP LAPSE RATES REMAIN THROUGH THURSDAY ALONG WITH ANOTHER SHORT
WAVE AND COLD PUSH COMING DOWN...EXPECT MORE ISOLATED TO SCATTERED
SNOW SHOWERS/FLURRIES AGAIN ON THURSDAY. WITH PLENTY OF LOW AND
MID LEVEL RH...EXPECT THE CLOUDS TO REMAIN THROUGH THURSDAY NIGHT
AND FRIDAY. ADDED IN AND EXPANDED SCATTERED FLURRIES INTO FRIDAY
ACROSS MUCH OF THE CWA AS THE WEATHER PATTERN STAYS THE SAME WITH
DEEP NORTHERLY FLOW. TEMPERATURES WILL NOT RISE MUCH TODAY WITH
CAA AND CLOUD COVER. TEMPERATURES ON THURSDAY AND FRIDAY WILL BE
COOLER AS WE BRING DOWN SOME MORE COLD AIR BEHIND THE FRONTAL
PASSAGE TODAY AND THIS EVENING.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
THE EXTENDED MODELS ARE IN PRETTY GOOD AGREEMENT THROUGH THE FIRST
HALF OF THE PERIOD...THEN BEGIN TO DIVERGE IN THEIR SOLUTIONS. AN
UPPER LEVEL TROUGH WILL EXTEND FROM EASTERN CANADA DOWN THE PLAINS
FRIDAY EVENING...WITH WEAK RIDGING OVER THE ROCKIES AND ANOTHER
SHORTWAVE OVER THE PACIFIC NORTHWEST. THE SOUTHERN PORTION OF THE
LEADING TROUGH SLIDES EAST FRIDAY NIGHT...WHILE THE NORTHERN
PORTION OF THIS TROUGH AND THE WESTERN SHORTWAVE BEGIN TO MERGE.
THIS TROUGH REMAINS ELONGATED FROM EASTERN CANADA TO THE PACIFIC
NORTHWEST SATURDAY AND SUNDAY...WITH THE PACIFIC NORTHWEST PORTION
OF THE TROUGH STRENGTHENING SOME ON SUNDAY. ON MONDAY...THE ECMWF
KEEPS BROAD TROUGHINESS ACROSS THE COUNTRY...WITH THE WESTERN LOW
WEAKENING SIGNIFICANTLY. THE GFS SHOWS THE WESTERN LOW DROPPING
SOUTHEAST AND BECOMING A TROUGH EXTENDING FROM EASTERN MONTANA TO
SOUTHERN CALIFORNIA. TUESDAY...THE ECMWF STRENGTHENS THE SHORTWAVE
TROUGH AND SLIDES IT FROM THE SOUTHERN ROCKIES TO THE KS/OK/MO
REGION LATE TUESDAY NIGHT. THE GFS SLIDES THE TROUGH FROM WEST OF
THE ROCKIES TO DIRECTLY OVER THE PLAINS. MOST OF THE GFS
ENSEMBLES ARE MORE IN LINE WITH THE OPERATIONAL GFS.

AT THE SURFACE...LOW PRESSURE WILL BE OVER MONTANA FRIDAY EVENING
WITH A TROUGH DOWN THE LEE OF THE ROCKIES. THIS LOW DROPS SOUTH
DURING THE NIGHT...DRAGGING A COLD FRONT ACROSS THE CWA LATE. THE
FRONT CONTINUES TO PUSH SOUTH AND EAST OF THE REGION ON
SATURDAY...WITH HIGH PRESSURE CENTERED OVER NORTHWEST CANADA
BEGINNING TO NOSE OVER THE DAKOTAS. THE HIGH BECOMES ELONGATED
FROM SOUTHWESTERN CANADA DOWN THE PLAINS ON SUNDAY. ON
MONDAY...THE ECMWF SHOWS THE HIGH TRACKING ACROSS THE PLAINS AND
EAST OF THE REGION WITH LOW PRESSURE INTENSIFYING OVER SOUTHERN
WYOMING/COLORADO. THE GFS BROADENS THE HIGH ACROSS THE ENTIRE
NORTHERN AND EASTERN UNITED STATES...WITH LOW PRESSURE
STRENGTHENING OVER THE FOUR CORNERS REGION. BOTH MODELS SHOW THE
LOW TRACKING ACROSS THE SOUTHERN PLAINS ON TUESDAY...BUT THE GFS
IS STRONGER AND SLOWER BOTH WITH THE SOUTHERN LOW AND WITH HIGH
PRESSURE APPROACHING FROM THE NORTHWEST BEHIND THE EXITING LOW.
ONLY REAL CHANCE FOR PRECIPITATION LOOKS TO COME LATE IN THE
PERIOD WHEN BOTH MODELS INDICATE LIGHT SNOW ON THE NORTH SIDE OF
THE LOW POSSIBLY SPREADING AS FAR NORTH AS SOUTH DAKOTA MONDAY
NIGHT AND TUESDAY.

H85 TEMPS REMAIN IN THE TEENS BELOW ZERO THROUGH THE
PERIOD...LIKELY RESULTING IN BELOW NORMAL SURFACE TEMPERATURES.
HIGHS IN THE 20S AND LOWS IN THE SINGLE DIGITS TO LOWER TEENS WILL
BE COMMON.

&&

.AVIATION...
MVFR CIGS BETWEEN 1500-2500 FEET WILL REMAIN OVER THE EASTERN CWA
THROUGH THE MID MORNING HOURS...MAINLY AFFECTING KATY.
OTHERWISE...VFR CONDITIONS WILL PREVAIL...WITH SCT-BKN CLOUDS AOA
3500 FEET SPREADING FROM WEST TO EAST. VSBYS WILL BE UNRESTRICTED.

&&

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

$$
SHORT TERM...MOHR
LONG TERM...PARKIN
AVIATION...PARKIN

WEATHER.GOV/ABERDEEN