FXUS63 KDDC 052145
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
345 PM CST SAT DEC 5 2009
.DISCUSSION...
DAYS 1-2...
A PROGRESSIVE SHORTWAVE TROUGH WAS LOCATED OVER NEVADA THIS MORNING.
A COLD FRONT WAS SITUATED ACROSS CENTRAL NEBRASKA. TEMPERATURES WERE NOT
THAT COLD IMMEDIATELY BEHIND THE FRONT. COLDER TEMPS IN THE 20S
WERE LOCATED ACROSS NORTHWEST SD. AFTER MIDDAY HIGHS FROM 45 TO
50F, TEMPERATURES WERE DECLINING EARLY AFTERNOON IN WESTERN KS AS
HIGH CLOUDS THICKENED. WINDS BEHIND THE COLD FRONT ARE PROGGED TO
TURN UPSLOPE TONIGHT AHEAD OF THE SHORTWAVE. THIS MAY AID IN LOW
CLOUD DEVELOPMENT TOWARD MORNING IN OUR WEST AND NORTH AND MAYBE
EVEN IN DDC BY 12Z. WITH HIGH CLOUD COVER ALL NIGHT, INCREASING
LOW CLOUD COVER TOWARD MORNING, AND THE LACK OF VERY COLD AIR
ACROSS NEBRASKA, TEMPS WILL STAY A LITTLE WARMER TONIGHT THAN IN
PREVIOUS NIGHTS.
AS THE SHORTWAVE TROUGH APPROACHES SUNDAY, A SHALLOW COLD/MOIST LAYER
AND LOW LEVEL LIFT SHOULD ALLOW FREEZING DRIZZLE/LIGHT SNOW TO
DEVELOP. SIGNIFICANT SNOW ACCUMULATIONS ARE NOT EXPECTED IN
GCK/DDC BUT THERE COULD BE A DUSTING IN CENTRAL KS. FCST SOUNDINGS
ARE RIGHT ON THE BORDER BETWEEN FREEZING DRIZZLE AND LIGHT SNOW,
SO I OPTED TO INCLUDE BOTH IN THE FCST. IF FREEZING DRIZZLE
DEVELOPS THEN SIDEWALKS AND POSSIBLY ROADS COULD BECOME SLICK.
TEMPERATURES WILL PROBABLY HOLD STEADY DURING THE DAY. FCST
SOUNDINGS SHOW A SUPERADIABATIC PROFILE NEAR THE SFC AND DRY
ADIABATIC PROFILE ABOVE THAT UP TO 850MB. THE MODELS TYPICALLY
OVERESTIMATE MAX TEMPS IN THESE CIRCUMSTANCES. DECIDED TO UNDERCUT
THE MODEL 2M TEMPS BY 2-4F. THE PRECIP SHOULD SHIFT INTO CENTRAL
AND EASTERN KS BY LATE AFTERNOON.
AFTER THE SHORTWAVE PASSES, SKIES SHOULD AT LEAST PARTIALLY CLEAR
SUNDAY NIGHT. WINDS ARE PROGGED TO STAY AT LEAST 10 KTS ALL NIGHT WITH
CONTINUED LEVEL COLD ADVECTION. TEMPS OUGHT TO FALL INTO THE
TEENS MOST PLACES BUT THE WIND MAY KEEP TEMPS FROM BOTTOMING OUT
IN THE SINGLE DIGITS. SOME SUNSHINE IS EXPECTED AGAIN MONDAY AS SW
KS WILL BE BETWEEN UPPER SYSTEMS AND DUE TO THE LACK OF STRONG
COLD OR WARM/MOIST ADVECTION THIS MAY ALLOW TEMPS TO RECOVER INTO THE
MID TO HIGH 20S. A WARM ADVECTION PATTERN WILL BE DEVELOPING BY
MONDAY AFTERNOON IN OUR WESTERN COUNTIES. ABUNDANT LOW LEVEL
MOISTURE FROM THE GULF OF MEXICO ALONG WITH COOL UPSLOPE FLOW
NORTH OF THE FRONT WILL LEAD TO RAPID LOW CLOUD DEVELOPMENT
TOWARD 00Z.
DAYS 3-7...
MAJOR QUESTIONS REMAIN REGARDING THE MONDAY NIGHT-TUESDAY
FORECAST...MAINLY WITH RESPECT TO TEMPERATURES AND PRECIPITATION
TYPE. MONDAY NIGHT...MASSIVE WARM ADVECTION WILL COMMENCE IN THE
800-900MB LAYER WITH LOW STRATUS DEVELOPING AND CYCLOGENESIS
OCCURRING OVER THE ROCKIES. IT WILL BE A CLASSIC BATTLE BETWEEN
VIGOROUS WARM ADVECTION AND DENSE, COLD ARCTIC AIR.
TYPICALLY...SHALLOW ARCTIC AIRMASS OF THIS MAGNITUDE IS NEXT TO
IMPOSSIBLE TO ERODE AWAY QUICKLY...HOWEVER IF THE SYNOPTIC SETTING
IS RIGHT...THEN IT CAN ERODE AWAY AT THE SURFACE...BUT IT TAKES VERY
INTENSE CYCLOGENESIS TO THE WEST IN ORDER TO DO SO. THE TUESDAY
EVENT APPEARS TO BE SHAPING UP TO BE SUCH A CASE.
ORDINARILY...SURFACE LOW WOULD DEVELOP AT THE EDGE OF THE ARCTIC
AIRMASS...THEN TRAVEL SOUTHEAST ALONG THE EDGE OF THE ARCTIC AIRMASS
INTO WEST TEXAS...THEN EAST ALONG THE RED RIVER BEFORE EJECTING
NORTHEAST IN THE TYPICAL "PANHANDLE HOOK" TRACK. ALL MODEL GUIDANCE
SUGGEST THE LOW WILL DEVELOP OVER THE COLORADO ROCKIES WITH THE
CYCLONE MATURING OVER SOUTHEAST COLORADO...BEFORE TRACKING EAST OR
EAST-SOUTHEAST ACROSS FAR SOUTHWEST KANSAS INTO FAR NORTHWEST
OKLAHOMA...THEN ACROSS CENTRAL/EASTERN KANSAS. THIS TRACK WOULD NOT
FAVOR HEAVY SNOW ACROSS THE DDC FA...EXCEPT PERHAPS ALONG INTERSTATE
70. OF MOST CONCERN ACTUALLY WILL BE SUSTAINED FREEZING DRIZZLE
TUESDAY...EVEN THOUGH THE CURRENT UPDATED FORECAST WILL REFLECT A
MYRIAD OF SNOW/SLEET/FREEZING RAIN MIX. DEEPEST MOISTURE WILL BE
CONFINED TO AREAS ALONG AND NORTH OF INTERSTATE 70 THROUGHOUT THE
EVENT. A WARM NOSE WILL DEVELOP WITH VERY STRONG SOUTHWESTERLY
DOWNSLOPE MOMENTUM JUST SOUTH OF THE SURFACE LOW. THIS WARM NOSE
MAY ACTUALLY PROTRUDE AS FAR NORTH AS LIBERAL. THE FORECAST HIGH
TEMPERATURE AT LIBERAL TUESDAY HAS AN EXTREME BUST POTENTIAL. THE
PREVIOUS FORECAST HIGH AT LIBERAL FOR TUESDAY WAS IN THE MID 20S.
IT IS CONCEIVABLE TO THINK GIVEN THE LATEST FORECAST TRACK OF THE
SURFACE CYCLONE...THAT IT COULD HIT 50F DURING THE MID-LATE
AFTERNOON HOURS TUESDAY AT LIBERAL...WHILE MID 20S WOULD BE HOLDING
TOUGH ACROSS WEST-CENTRAL KANSAS. THE UPSHOT IS...THERE WILL BE A
VERY TIGHT THERMAL GRADIENT WHERE THE LOW TRACKS.
VERY COLD ARCTIC AIR WILL MOVE RIGHT BACK IN...IN THE WAKE OF THE
LOW TUESDAY NIGHT...WITH DRIVING NORTH WINDS WELL INTO WIND ADVISORY
CRITERIA IF NOT APPROACHING HIGH WIND WARNING CRITERIA OVER A SMALL
AREA NORTHWEST OF THE SURFACE LOW. THIS WOULD CAUSE SIGNIFICANT
BLOWING AND DRIFTING UP ALONG INTERSTATE 70 GIVEN AN APPRECIABLE
AMOUNT OF ACCUMULATING SNOW...SO WILL MAINTAIN THE BLOWING SNOW IN
THE GRIDS UP IN TREGO AND ELLIS COUNTIES. THE REMAINDER OF THE WEEK
WILL REMAIN COLD AND HAVE LOWERED MAXIMUM TEMPERATURES AS A RESULT.
&&
AVIATION...
COLD FRONT WILL BE MOVING SOUTH OVERNIGHT...REACHING SOUTHWEST
KANSAS AFTER MIDNIGHT. BEHIND THE FRONT...LOW CEILINGS ARE EXPECTED
TO DEVELOP IN STRATUS...WITH MOST CRITICAL CEILINGS DEVELOPING JUST
NORTH AND NORTHWEST OF THE SURFACE VORTICITY CENTER...WHICH BY 12Z
IS EXPECTED TO BE ACROSS FAR NORTHWEST OKLAHOMA...THUS KDDC WILL
LIKELY SEE A PERIOD OF LIFR/IFR CEILINGS/VISIBILITY IN THE 10-16Z
TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 24 26 15 27 / 0 30 0 0
GCK 23 24 14 25 / 0 30 0 0
EHA 24 26 15 28 / 0 20 0 0
LBL 25 28 16 29 / 0 20 0 0
HYS 22 24 15 25 / 0 60 0 0
P28 27 35 19 30 / 0 30 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN24/25
