FXUS63 KFSD 251413
AFDFSD
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
812 AM CST WED NOV 25 2009
.DISCUSSION....
QUICK UPDATE THIS MORNING TO DROP POPS AS WESTERN EDGE OF PRECIP
SHIELD IS RAPIDLY ERODING AWAY. THOUGH UPPER LEVEL JET STREAK IS
MOVING INTO WESTERN AND CENTRAL SOUTH DAKOTA...CURVATURE OF THE FLOW
IS DOMINATING FEATURE SUPPORTING PRECIPITATION FURTHER TO THE SOUTH
AND EAST THAN ONE MIGHT EXPECT. BREEZY DAY EXPECTED BORDERING ON
WIND ADVISORY CRITERIA. PRESSURE COUPLET MAINLY FOCUSED ACROSS
WESTERN SOUTH DAKOTA INTO WESTERN NEBRASKA...AND WHILE THINK WINDS
WILL APPROACH WIND ADVISORY...THINK THEY WILL REMAIN BELOW ADVISORY
CRITERIA FOR NOW. /BT
&&
.PREV DISCUSSION...
QUICK MOVING UPPER LEVEL LOW CURRENTLY CENTERED NEAR THE MN/ND/SD
BORDER WILL DROP SE ACROSS THE CWA TODAY...BRINGING A SHOT OF SNOW
MAINLY TO EASTERN AREAS. THIS IS A VERY DYNAMIC SYSTEM...BUT AS IT
IS MOVING SO QUICKLY...SNOW AMOUNTS WILL BE LIMITED. COULD BE A MIX
OF RAIN OR SNOW INTO NW IA THIS MORNING...BUT TEMPERATURES ALOFT
COOL ENOUGH THAT ALL PRECIPITATION SHOULD SWITCH TO SNOW...EVEN IF
SURFACE TEMPERATURES REMAIN ABOVE FREEZING. SNOW ACCUMULATIONS WILL
MAINLY BE CONFINED OF AREAS EAST OF INTERSTATE 29...AND GENERALLY
EXPECTING 1 INCH OF SNOW ALONG AND EAST OF THE BUFFALO RIDGE...BUT
WOULD NOT RULE OUT ISOLATED 2 INCH AMOUNTS IN THIS AREA. IT HAS BEEN
TOUGH TO GAUGE THE RATE OF SNOW FALL INTO NE SD AND ERN ND THIS
MORNING DUE TO A LACK OF OBSERVATION SITES...HOWEVER...JMS REPORTED
5 HRS OF SN WITH VSBYS AROUND 3/4 MILE FOR A FEW HOURS. EXPECTING
SIMILAR CONDITIONS ALONG AND EAST OF THE BUFFALO RIDGE. NOT
EXPECTING ENOUGH SNOW ACCUMULATIONS FOR AN ADVISORY...BUT VSBYS
COULD DROP BELOW 1/2 SM FOR A FEW HOURS IN PLACES...AND WHEN
COMBINED WITH STRONG NW WINDS...COULD MAKE FOR TRICKY TRAVEL FOR A
SHORT TIME TODAY. THE UPPER LEVEL DISTURBANCE RESPONSIBLE FOR THE
SNOW WILL EXIT THE AREA JUST AS FAST AS IT APPEARED. SNOW SHOULD
PRETTY WELL BE OVER BY SUNSET...EXCEPT MAYBE A FEW LINGERING
FLURRIES TOWARD MJQ/SPW/SLB. ELECTED NOT TO ISSUE A WIND ADVISORY
TODAY...BUT WINDS WILL BE MARGINAL ALONG THE MO VALLEY. 40 TO 50 KT
NW FLOW IS IN PLACE AT 850 MB THIS MORNING...BUT DOES NOT APPEAR
THESE WINDS WILL BE ABLE TO COMPLETELY MIX TO THE SFC. WOULD LIKE TO
SEE SLIGHTLY STRONGER CAA FOR AN ADVISORY. STILL...SHOULD SEE SOME
30 MPH SUSTAINED WINDS WITH GUSTS OVER 40 MPH.
CLEARING SKIES WEST TO EAST TONIGHT AND DECREASING WINDS AS HIGH
PRESSURE BUILDS INTO THE AREA. COOL HIGH PRESSURE REMAINS IN PLACE
TOMORROW...WITH TEMPERATURE ONLY RISING INTO THE 30S IN THE EAST AND
40S WEST. ALTHOUGH THIS IS SOME OF THE COOLEST AIR WE HAVE SEEN THIS
SEASON...IT IS RIGHT AROUND NORMAL.
NOT MUCH GOING ON IN THE WAY OF WEATHER THOUGH EARLY NEXT WEEK.
UPPER RIDGE TO KEEP THINGS DRY THROUGH SATURDAY. A TROUGH DROPS INTO
THE NORTHERN PLAINS ON SUNDAY...WHICH COULD BRING SOME LIGHT SNOW
SHOWERS TO THE AREA...HOWEVER THERE MAY NOT MUCH MOISTURE TO WORK
AND LOOKS LIKE THE NRN STREAM WAVE MAY BE WEAK...WITH STRONGER SRN
STREAM WAVE OVER TX. 97
&&
.AVIATION...
AREAS MVFR CIGS AND GUSTY NWLY WINDS WILL FOLLOW A COLD FRONT MOVING
SOUTHEAST ACROSS THE AREA EARLY THIS MORNING. THE UPPER LEVEL WAVE
DRIVING THE COLD FRONT WILL PRODUCE PERIODS OF LIGHT RAIN OR SNOW
SHOWERS...MAINLY EAST OF INTERSTATE 29...TAPERING OFF AFTER 21Z AS
THE UPPER WAVE MOVES SOUTHEAST OF THE REGION. PERIODS OF MVFR VSBYS
IN -SHSN POSSIBLE AT KHON/KFSD TAF LOCATIONS...WITH BETTER CHANCE OF
IFR VSBYS XPCTD TO REMAIN OVER SWRN MN/NWRN IA. WND GUSTS OF 25-35KT
BEHIND THE COLD FRONT WILL PERSIST MUCH OF THE DAY...DMNSHG AFTER
26/00Z AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM THE WEST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
$$
