917
FXUS63 KDDC 202133
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
333 PM CST FRI NOV 20 2009
DISCUSSION
DAYS 1-2...
THE MAIN FORECAST CHALLENGES WILL BE WINDS ON SATURDAY AND HOW FAR
WEST THE STRATUS MOVES ON SATURDAY NIGHT.
A DEEP UPPER LEVEL SHORTWAVE TROUGH MOVING ONSHORE OVER THE WESTERN
CONUS WILL MOVE INTO THE CENTRAL AND NORTHERN PLAINS BY SUNDAY
MORNING THEN ACROSS WESTERN KANSAS SUNDAY. A SOUTHERN BRANCH
SHORTWAVE TROUGH OVER TEXAS COMBINED WITH A WEAKER NORTHERN BRANCH
WAVE OVER KANSAS WILL MOVE EASTWARD TONIGHT BUT MAY SPREAD SOME
CLOUDINESS INTO THE FAR SOUTHEAST FA BEFORE MOVING OUT. SOUTHERLY
FLOW BEGINNING TONIGHT WILL SLOWLY INCREASE DEWPOINTS INTO SUNDAY.
THE PRESSURE GRADIENT TIGHTENS ON SATURDAY AFTERNOON WITH SOUTH
WINDS INCREASING TO 15 TO 25 MPH WITH HIGHER GUSTS. THEN
SOUTHEASTERLY WINDS DRAW BETTER MOISTURE INTO SOUTHWESTERN KANSAS ON
SATURDAY NIGHT LEADING TO STRATUS FORMATION, HOWEVER WESTERN EXTENT
IS THE QUESTION. THE WRF SHOWS THE FARTHEST WEST TOWARDS GARDEN
CITY BY SUNDAY MORNING. SOME UPWARD MOTION ASSOCIATED WITH THE UPPER
LEVEL WAVE COULD CAUSE A FEW SHOWERS MAINLY FAR EAST AND WILL LEAVE
A VERY LOW POP EAST TO COVER. INSTABILITY LOOKS VERY MINIMAL WITH A
GOOD CAPPING INVERSION FOR SUNDAY AND A LACK OF MID LEVEL MOISTURE.
FOR TONIGHT LOOK FOR CLEAR SKIES WITH LIGHT AND VARIABLE WINDS
BECOMING SOUTH AROUND MIDNIGHT AND INCREASING. SOME CIRRUS CLOUDS
WILL INCREASE FAR WEST BY MORNING. OVERNIGHT LOWS IN THE UPPER 20S
TO LOWER 30S LOOKS REASONABLE WITH THE WARMEST IN THE MID 30S AROUND
MEDICINE LODGE WITH THE BETTER DEWPOINTS. ON SATURDAY LOOK FOR
INCREASING HIGH LEVEL CLOUDINESS WITH WINDS INCREASING TO 15 TO 25
MPH. HIGHS WITH GOOD MIXING SHOULD MAKE IT TO AROUND 60 DEPENDING ON
HOW THICK THE CIRRUS CLOUDS GET. THEN FOR SATURDAY NIGHT LOOK FOR
INCREASING STRATUS CLOUDS TO MOVE INTO THE CENTRAL FA AS HIGH
CLOUDINESS PUSHES EAST. WINDS SHOULD BE FROM THE SOUTHEAST AND STAY
IN THE 15 TO 22 MPH RANGE. FOR SUNDAY LIGHT SOUTHEAST WINDS BECOME
LIGHT AND VARIABLE WITH CLOUDY TO MOSTLY CLOUDY SKIES IN THE MORNING
BECOMING PARTLY CLOUDY IN THE AFTERNOON AS THE SHORTWAVE PUSHES EAST.
DAYS 3-7...
THE FOCUS FOR THE MEDIUM RANGE FORECAST STILL REMAIN WITH THE
PROGRESSIVE TROUGHS MOVING ACROSS THE WESTERN UNITES STATES AND INTO
THE ROCKY MOUNTAIN/PLAINS REGION THROUGH EARLY NEXT WEEK, AND WHAT
RESULTING IMPACTS ARE MOST LIKELY FOR CENTRAL AND SOUTHWEST KANSAS.
THE CONSENSUS OF THE LAST 2 DAYS WORTH OF OPERATIONAL MODEL RUNS HAS
BEEN KEEPING SHORT WAVE ENERGY OR CYCLOGENESIS INDUCED FORCING FOR
PRECIPITATION ASSOCIATED WITH THE DEEP TROUGH MOVING INTO THE PLAINS
BY SUNDAY NIGHT AN MONDAY, TO THE NORTH OF OUR IMMEDIATE FORECAST
AREA. THIS MORNING'S 12 UTC GFS WAS NOT SURPRISING AND FAIRLY
CONSISTENT WITH REMAINING THE FASTEST AND FARTHEST NORTH MODEL, NOT
TO MENTION WEAKEST SOLUTION, WHILE THE ECMWF FAVORED A SLIGHTLY
DEEPER AND MORE INTENSE CYCLONIC CIRCULATION DEVELOPMENT.
OVERALL, THE MAIN ADJUSTMENTS TO THE FORECAST FOR THE MEDIUM RANGE
BEGUN WITH A STRONGER SURFACE WIND FORECAST FOR MONDAY AS A SURFACE
FRONT IS LIKELY TO PUSH THROUGH IN THE MORNING, AND PERHAPS CLEAR
THE KS/OK LINE BY AFTERNOON. WINDS IN THE 20-30 MPH RANGE WILL BE
POSSIBLE ESPECIALLY FOR A FEW HOURS BEHIND THE FRONT. AS WELL, WITH
BOUNDARY LAYER COLD ADVECTION EXPECTED, WE TRIMMED HIGHS ON MONDAY
WITH ABOUT A 10 DEGREES DIURNAL HIGH, WITH TEMPERATURES BY AFTERNOON
IN THE 40S.
PRECIPITATION TYPE WILL CONTINUE TO BE A CHALLENGE, HOWEVER, THE
MORE LIKELY SCENARIO WILL BE A DEEP LAYER DRY INTRUSION HAVING THE
GREATEST INFLUENCE ON OUR REGION. ONLY THE FARTHEST SOUTH SOLUTION
OF ECMWF PREDICTS LIGHT PRECIPITATION/QPF AMOUNTS IN OUR NORTHERN AND
EASTERN SECTIONS. A LOOK AT THE ECMWF'S THERMODYNAMIC PROFILES
INDICATES MARGINALLY COLD 850 MB AIR IN THE DRY CONVEYOR BELT WHILE
1000-500 MB CRITICAL THICKNESS REACH THE 540 DM LINE ONCE THE
DEFORMATION AXIS LIFTS NORTHEAST FORM TEH CENTRAL PLAINS. THEREFORE,
WE HAVE KEPT WITH 10-20 POPS FOR RAIN OR RAIN SHOWERS UNTIL MONDAY
EVENING, WHEN A MENTION OF SCATTERED SPRINKLES OR FLURRIES SEEMS
APPROPRIATE.
IN THE TIMEFRAME BEYOND, A DECREASE IN CLOUD COVER AND A COUPLE OF
DAYS OF SLIGHTLY COLDER THAN NORMAL TEMPERATURES ARE EXPECTED, AS
COOL HIGH PRESSURE SPREADS SOUTHWARD INFLUENCING HE PLAINS STATES.
ECMWF 850 TEMPERATURES IN THE 0 DEG C TO -8 DEG C RANGE WOULD SUPPORT
STICKING WITH BELOW CLIMATOLOGY HIGHS AND CONTINUED DRY WEATHER INTO
LATE IN THE WEEK. OVERALL, THE FORECAST WAS HEDGED CLOSER TO THE
ECMWF SOLUTION.
PRELIMINARY POINT TEMPS/POPS
DDC 32 60 38 53 / 0 0 0 0
GCK 30 60 36 55 / 0 0 0 0
EHA 33 61 36 55 / 0 0 0 0
LBL 31 62 36 56 / 0 0 0 0
HYS 29 58 37 53 / 0 10 10 10
P28 40 60 43 58 / 0 10 10 10
DDC WATCHES/WARNINGS/ADVISORIES
NONE.
FN06/33
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