FXUS63 KDDC 041950
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
150 PM CST FRI DEC 4 2009
.DISCUSSION...
DAYS 1-2...
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATES A BROAD UPPER
LEVEL TROUGH OF LOW PRESSURE TRANSITIONING EAST ACROSS THE CENTRAL
PLAINS. MEANWHILE, ANOTHER UPPER LEVEL TROUGH IS DIGGING SOUTH
ACROSS EXTREME SOUTHERN BRITISH COLUMBIA AND JUST EDGING INTO THE
PACIFIC NORTHWEST. A +100KT UPPER LEVEL JET IS DIVING SOUTH ACROSS
WESTERN WYOMING AND DOWN INTO THE FOUR CORNERS REGION. IT THEN
CONJOINS WITH THE SUBTROPICAL JET IN THE UPPER LEVEL TROUGH AXIS
ACROSS THE SOUTH PLAINS AND BEGINS TO CLIMB NORTHEAST ACROSS THE
SOUTHEASTERN CONUS. SURFACE HIGH PRESSURE CONTINUES TO DOMINATE
ACROSS SOUTHWEST KANSAS AND THE PANHANDLES OF OKLAHOMA AND TEXAS.
SHORT RANGE MODELS ARE IN GENERAL AGREEMENT INDICATING THE UPPER
LEVEL TROUGH ACROSS THE CENTRAL PLAINS PUSHING OFF TO THE EAST OUT
OF THE REGION BY EARLY SATURDAY MORNING. MEANWHILE, THE SECONDARY
UPPER LEVEL TROUGH IN THE PACIFIC NORTHWEST, WILL CONTINUE TO DROP
SOUTH MOVING INTO THE GREAT BASIN REGION LATE SATURDAY BEFORE
STALLING OUT. AS THE BROADER SCALE UPPER LEVEL TROUGH REMAINS ACROSS
THE WESTERN CONUS, A SMALLER EMBEDDED S/WAVE TROUGH WILL EJECT
EAST ACROSS THE ROCKIES AND INTO THE WESTERN HIGH PLAINS SUNDAY.
THIS FEATURE WILL HELP PUSH A COLD FRONT INTO WESTERN KANSAS ALONG
WITH THE POSSIBILITY FOR PRECIP WITH IT BY LATE SUNDAY. THE NAM,
GFS, AND UKMET SHOW AN H5 VORT MAX EJECTING OUT FROM THE ROCKIES
AND ACROSS WESTERN KANSAS IN A MID DAY TO LATE AFTERNOON TIME
FRAME. HOWEVER, THEY ALL INDICATE THAT OTHER UPPER LEVEL SUPPORT
FACTORS WILL BE MINIMAL INCLUDING THE ABSENCE OF A STRONG UPPER LEVEL
JET AND FAIRLY WEAK H7 FRONTOGENESIS BEHIND THE FRONT. AS A RESULT OF
THIS, SEE NO REASON TO ELEVATE POPS AT THIS TIME KEEPING SLIGHT
POPS IN ACROSS MUCH OF THE FORECAST AREA WITH 30 POPS ACROSS THE
EXTREME NORTHERN PORTION OF THE CWA. ANY PRECIP WOULD LIKELY BE
ALL SNOW AS NAM AND GFS MODEL SOUNDINGS SHOW TEMPERATURE PROFILES
REMAINING WELL BELOW 0C FROM THE SURFACE ON UP THROUGH MID AND
UPPER LEVELS.
TEMPERATURES TONIGHT WILL AGAIN BE WELL BELOW FREEZING, EVEN AS A
LEE SIDE TROUGH OF LOW PRESSURE DEVELOPS BRINGING SOUTHERLY WINDS
BACK ACROSS WESTERN KANSAS. ALTHOUGH, THIS WILL BE ENOUGH TO RAISE
LOWS FROM THE NIGHT PREVIOUS BY JUST A FEW DEGREES, ESPECIALLY
WITH H85 TEMPERATURES BACK UP NEAR TO JUST ABOVE 0C ACROSS
SOUTHWEST KANSAS. EXPECT LOWS DOWN INTO THE TEENS(F) ACROSS MUCH
OF THE FORECAST AREA. FOR SATURDAY, SOUTHERLY WINDS AND MOSTLY
CLEAR SKIES WILL ALLOW HIGH TEMPERATURES TO CLIMB A LITTLE FROM
FRIDAY. TEMPERATURES AT H85 WILL BE JUST ABOVE 0C ACROSS SOUTHWEST
KANSAS. HIGHS ARE EXPECTED UP INTO THE 40S(F) ACROSS THE ENTIRE
CWA JUST AHEAD OF AN APPROACHING COLD FRONT. FOR SATURDAY NIGHT,
LOWS WILL AGAIN BE WELL BELOW FREEZING IN WAKE OF A COLD FRONT
PUSHING ACROSS SOUTHWEST KANSAS. THIS WILL ALLOW COLDER AIR TO
FILTER SOUTH INTO THE AREA DROPPING LOWS BACK DOWN INTO THE
TEENS(F) ACROSS MUCH OF THE CWA. STRONG COLD AIR ADVECTION ACROSS
WESTERN KANSAS SATURDAY WILL KEEP HIGH TEMPERATURES DOWN WELL
BELOW NORMAL AS WELL. THE NAM, GFS, AND UKMET ALL SHOW TEMPERATURES
AT H85 RANGING FROM AROUND 5C BELOW ACROSS SOUTHERN PORTIONS OF
THE FORECAST AREA TO NEAR 10C BELOW ACROSS OUR NORTH. HIGHS WILL
ONLY CLIMB INTO THE 20S(C) ACROSS ACROSS SOUTHWEST KANSAS WITH
NEAR 30F POSSIBLE IN OUR EXTREME SOUTHEAST. HIGHS SHOULD ALSO
OCCUR EARLIER IN THE DAY WITH TEMPERATURES STEADY OR FALLING
THROUGH THE AFTERNOON. PLAN TO LOWER HIGHS A COUPLE DEGREES OR SO
SATURDAY WITH MINOR ADJUSTMENTS ELSEWHERE.
DAYS 3-7...
IN THE EXTENDED, A COLD FRONT IS POISED TO BRING ANOTHER SHOT OF
COLD AIR IN SUNDAY, WITH AN UPPER WAVE CROSSING JUST NORTH OF OUR
CWA. THIS UPPER WAVE SHOULD PROVIDE SOME SYNOPTIC LIFT OVER THE
COLD AIR, AND PRODUCE LIGHT FREEZING DRIZZLE SUNDAY NIGHT INTO
MONDAY. THEN, A MUCH LARGER SYSTEM WILL PRODUCE A MUCH MORE
AMPLIFIED UPPER TROUGH COMING THROUGH THE CENTRAL PLAINS MONDAY
NIGHT INTO EARLY WEDNESDAY. THE WAY THE GFS AND CANADIAN MODELS
BOTH BRING THE UPPER SYSTEM MORE ALONG A SOUTHERN TRAJECTORY (THAN
THE ECMWF AND UKMET), ONE WOULD EXPECT SIGNIFICANT SNOW IN OUR
NORTHERN COUNTIES, PERHAPS 2 TO 3 INCHES. WAITED TO VIEW THE 06Z RUN
OF THE GFS, AND IT IS NEARLY THE SAME AS THE PREVIOUS 00Z RUN.
BUT THE ECMWF IS KEEPING THE UPPER AMPLIFIED WAVE MORE NORTH, IN THE
VICINITY OF SOUTH DAKOTA AND NEBRASKA, ONLY SKIMMING OUR NORTHERN
CWA WITH MEASURABLE SNOW. SO BOTH MEDIUM TO LONG RANGE MODELS ARE
KEEPING WITH THEIR PREVIOUS RUN'S SOLUTION, AND NOT VEERING TOWARD A
COMMON SOLUTION YET. DID NOT WANT TO ALTER THE GOING EXTENDED TOO
MUCH YET, BUT WAIT FOR A CONVERGING MODEL SOLUTION LATER.
WITH THIS IN MIND, AND IN AN EFFORT TO COLLABORATE WITH OTHER
OFFICES TO OUR NORTH, HAVE INCREASED POPS SLIGHTLY OVER OUR NORTHERN
AND EASTERN SECTIONS OF THE CWA FOR TUESDAY AND TUESDAY NIGHT.
RIGHT NOW, WILL ONLY GO IN THE UPPER RANGE OF THE 40 PERCENT POP
CATEGORY, GIVING SOME ROOM FOR ADJUSTING UPWARD BY LATER SHIFTS IF
THE MODELS HOLD FAST, OR GOING DOWNWARD IF THE EC AND UKMET TURN OUT
TO BE CORRECT. TEMPERATURES WILL BE COOLING OFF TUESDAY AND
WEDNESDAY WITH THE COLD AIR AND SNOW COMING IN, BUT CLOUDS WILL HELP
TO PREVENT DIURNAL RADIANT COOLING. SO EXPECT HIGHS IN THE MID 20S
NORTH TO NEAR 30F IN THE SOUTH MONDAY INTO WEDNESDAY, THEN WARMING
BY FRIDAY INTO THE MID 30S NORTH TO THE 45F TO 50F DEGREE RANGE IN
THE SOUTH ALONG THE OKLAHOMA BORDER. LOW TEMPERATURES WILL BE
CHILLY, STARTING OUT IN THE RANGE OF 10F DEGREES NORTHWEST TO NEAR
18F DEGREES IN THE SOUTHEASTERN CWA ON WEDNESDAY, WARMING TO A RANGE
ON FRIDAY FROM 14F DEGREES NORTHWEST TO 25F DEGREES SOUTH. MIN T'S
SHOULD BE SIMILAR TO FRIDAY'S FOR SATURDAY MORNING.
&&
.AVIATION...
VFR CONDITIONS TO PREVAIL THROUGH 24 HOURS. THE NORTHWEST FLOW
ALOFT ASSOCIATED WITH A BROAD TROUGH MOVING THROUGH THE PLAINS, BUT
WITH LITTLE ATTENDANT MOISTURE, WILL KEEP CLEAR SKIES OVER TAF
SITES. A DEVELOPING SURFACE TROUGH TO OUR WEST WILL SLOWLY SHIFT
THE LOW LEVEL WINDS FROM SOUTHWEST TO WEST, BECOMING LIGHT SOUTH
AFTER 23Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 13 45 18 28 / 0 0 10 30
GCK 10 45 17 27 / 0 0 10 30
EHA 15 47 17 27 / 0 0 10 20
LBL 12 47 18 28 / 0 0 10 20
HYS 12 43 17 27 / 0 0 10 30
P28 17 45 23 33 / 0 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN32/12/12
