FXUS63 KDDC 040932
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
332 AM CST FRI DEC 4 2009
.DISCUSSION...
DAYS 1-2...
HOW WARM WILL TEMPS GO WILL BE THE MAIN FORECAST QUESTION FOR THE
SHORT TERM.
UPPER OBS AS OF 00Z CONTINUE TO SHOW A MERIDONAL PATTERN WITH A
LARGE TROUGH FROM THE WESTERN GREAT LAKES INTO THE SOUTHERN
ROCKIES. SURFACE HIGH PRESSURE REMAINED OVER THE NORTHERN ROCKIES
DOWN INTO TX. VERY COLD TEMPS CONTINUED OVER THE PLAINS WITH -20 C
AT 700MB, -10 C AT 850MB, AND DOWN IN THE LOW TEENS AT THE SFC.
THE TROUGH AXIS WILL MOVE SLIGHTLY SOUTHEASTWARD TODAY, LEAVING
WESTERN KS IN NORTH TO NORTHWESTERLY FLOW ALOFT. THE SFC HIGH WILL
DROP SOUTH INTO TX, ALLOWING A LEE TROUGH TO REDEVELOP OVER THE
NORTHERN AND CENTRAL PLAINS. THIS SHOULD SHIFT WINDS TO THE WEST,
WHICH WILL HELP BRING DOWNSLOPE. THERE SHOULD BE PLENTY OF
SUNSHINE AND A DECENT AMOUNT OF MIXING. HOWEVER, WITH A FAIRLY
COLD START AND 850MB TEMPS STAYING BELOW ZERO C, HIGHS WILL ONLY
TOP OUT IN THE MID TO UPPER 30S. NORTHWESTERLY FLOW ALOFT WILL
CONTINUE INTO TONIGHT, WITH THE LEE SFC TROUGH BRINGING SOUTH TO
SOUTHWESTERLY WINDS. THIS SHOULD KEEP US FROM TOTALLY DECOUPLING
EVEN UNDER CLEAR SKIES, AND OVERNIGHT LOWS WILL BE A BIT MORE MILD
THAN THIS MORNING. HOWEVER, WITH DEWPOINTS STILL AROUND 10-12 F IT
WILL STILL GET FAIRLY COLD EVEN WITH DOWNSLOPE. KEPT LOWS IN THE
TEENS.
THE UPPER FLOW WILL BECOME NEAR ZONAL BY SATURDAY AS THE NEXT
POSITIVELY TILTED UPPER TROUGH MOVES INTO THE NORTHERN ROCKIES.
THE SFC TROUGH WILL MOVE SLIGHTLY EASTWARD, AND MODELS START
BRINGING THE NEXT COLD FRONT INTO NORTHWESTERN KANSAS BY SATURDAY
AFTERNOON. STILL, IT LOOKS LIKE THE CWA WILL STAY UNDER SOUTHERLY
SFC WINDS FOR MUCH OF THE DAY, AND 850MB TEMPS GET BACK ABOVE ZERO
C. CONTINUED WITH HIGHS MAINLY IN THE 40S, WITH THE HIGHER
READINGS IN THE SOUTHWEST. THE COLD AIR WILL START TO COME DOWN
SATURDAY NIGHT AS THE UPPER TROUGH BEGINS TO DIG INTO UT. CLOUD
COVER WILL ALSO BE INCREASING HOWEVER, SO LOWS SHOULD STAY IN THE
20S.
DAYS 3-7...
THE UPPER PATTERN OVER NORTH AMERICA WILL CONTINUE TO EXHIBIT A
HIGHLY AMPLIFIED RIDGE FEATURE OFF THE WEST COAST AND THE
DEVELOPMENT OF A CLOSED LOW AT THE BASE OF A STRONGLY POSITIVELY
TILTED TOUGH FROM CENTRAL CANADA INTO THE NORTHWEST PACIFIC STATES
BY EARLY NEXT WEEK. COLD AIR WILL CONTINUE TO MOVES SOUTH FROM THE
NORTHERN ROCKIES AND NORTHERN PLAINS DURING THE PERIOD. BY SUNDAY
SHORTWAVE ENERGY WILL BE ADVANCING THROUGH THE TROUGH INTO THE
CENTRAL ROCKIES AS A COLD FRONT MOVES SOUTH THROUGH KANSAS.
TEMPERATURES COLD ENOUGH AT THE SURFACE OVER MOST OF THE FORECAST
AREA COMBINED WITH INCREASING SATURATED BOUNDARY LAYER PROFILES
BEHIND WEAK SOUTHERLY MOISTURE ADVECTION TO WARRANT EITHER FREEZING
DRIZZLE OR LIGHT SNOW, ALONG WITH A FAIR DEGREE OF UNCERTAINTY.
THE BULK OF THE SHORTWAVE ENERGY WILL THEN EJECT FROM THE BASE OF
THE TROUGH SUNDAY NIGHT AND MONDAY, AND DEVELOP INTO A PLAINS
CYCLONE AROUND TUESDAY. THERE IS A HIGH AMOUNT OF SPREAD BETWEEN THE
MODEL SOLUTIONS ON THE STORM TRACK, WITH THE LATEST 00 UTC GEM
APPEARING FAR MORE IN LINE WITH THE GFS RUNS WHICH WOULD PLACE
BANDED SNOWFALL OF SEVERAL INCHES ACROSS CENTRAL KANSAS ON TUESDAY.
BY CONTRAST THE ECMWF AT THIS POINT IS STILL THE FARTHER NORTH
MODEL, WHICH WOULD PLACE THE PRECIPITATION EPISODE ACROSS NEBRASKA
AND EFFECTIVELY DRY SLOTTING SOUTHWEST KANSAS. WE WILL MAINTAIN THE
30-40 PERCENT CHANCES FOR SNOW ACROSS THE AREA TUESDAY, WITH THE
HIGH AMOUNT OF UNCERTAINTY THAT EXISTS.
&&
AVIATION...
LIGHT WESTERLY SURFACE WINDS WILL PERSIST THIS MORNING AND SKIES
WILL REMAIN CLEAR AS MAIN THE JET AND STRATUS CLOUDS REMAIN RELEGATED
TO THE HIGH PLAINS REGION OF NEW MEXICO AND THE NORTH TEXAS
PANHANDLE. THE SURFACE WINDS WILL PICK UP TO AROUND 16 KNOTS BY LATE
MORNING ONCE MIXING DEVELOPS, AND VEER TO A SOUTHERLY DIRECTION BY
THIS EVENING AS SLIGHT TROUGHING DEVELOPS TO THE LEE OF THE
ROCKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 36 14 45 21 / 0 0 0 10
GCK 36 12 46 19 / 0 0 0 10
EHA 38 14 47 19 / 0 0 0 10
LBL 38 13 47 21 / 0 0 0 10
HYS 35 13 44 21 / 0 0 0 10
P28 36 17 44 25 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN26/33/33
