FXUS63 KDDC 112120
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
320 PM CST FRI DEC 11 2009
.DISCUSSION...
DAYS 1-2...
DESPITE A FAIRLY BENIGN WEATHER PATTERN OVER THE CENTRAL PLAINS,
THERE ARE SOME FORECAST DIFFICULTIES DURING THE SHORT TERM. AM
WORRIED ABOUT THE POTENTIAL FOR ADVECTION FOG TONIGHT AS WELL AS
TEMPS THROUGHOUT THE SHORT TERM.
A RATHER PRONOUNCED SPLIT FLOW REGIME EXISTS ACROSS THE WESTERN
CONUS WITH THE CONFLUENCE OVER THE CENTER OF THE COUNTRY. A VERY
IMPRESSIVE JET PATTERN (DUE BOTH TO ITS STRENGTH AND AREAL COVERAGE)
EXISTS OVER THE EASTERN HALF OF THE NATION. A WIDESPREAD AREA
(COVERING DOZENS OF STATES) OF 140KT+ WINDS IS ANALYZED OVER THE
EAST WITH A FEW JET MAXIMA APPROACHING 200KT! THERE ARE REALLY
FEW FEATURES OF INTEREST IN THE MID AND LOW LEVELS OVER THE
CENTRAL PLAINS ATM AS A GENERAL WEAK WEST/NW FLOW PERSISTS.
WHAT IS INTERESTING IS NEAR THE SFC WHERE SNOW COVER CONTINUE TO BE
A MONKEY WRENCH IN THE FORECAST. TEMPS HAVE WARMED TO ABOVE FREEZING
SOUTH OF A LINE FROM ROUGHLY JOHNSON CITY TO PRATT. NORTH OF THAT
LINE IT IS STILL AOB FREEZING AND THIS IS DUE LARGELY TO PRESISTENT
SNOW COVER. PER SATELLITE IMAGERY, THE MELTING LINE IS BEGINNING TO
ADVANCE NORTHWARD WITH WEAK SOUTHERLY FLOW EATING AWAY AT IT, BUT
IT'S NOT LIKELY TO MAKE TOO MUCH MORE HEADWAY AS THE GROUND IS VERY
COLD AND DARKNESS APPROACHES. FURTHER SOUTH, WARMER AND SLIGHTLY
MORE MOIST AIR IS ADVECTING NORTHWARD THROUGH THE TX/OK PANHANDLES.
THIS MAKES ME CONCERNED ABOUT ADVECTION FOG DEVELOPING TONIGHT AS
THIS AIR MOVES OVER SNOW COVER OVER SW KS. HAVE INCREASED FOG
FORECAST FOR TONIGHT TO "AREAS OF" AND INCREASED COVERAGE TO LINE
UP WITH THE EXPECTED SNOW PACK. THINK THIS IS AN ALL OR NOTHING
PROPOSITION (IE P6SM OR 1/4SM) BUT THE MOISTURE IS NOT REALLY
IMPRESSIVE SO I HELD BACK TO LET LATER SHIFTS EVALUATE. WEAK
ISENTROPIC LIFT IS PRESENT THROUGH MUCH OF THE COLUMN SO STRATUS
IS ALSO A POSSIBILITY. DON'T THINK MOISTURE IS DEEP ENOUGH LOCALLY
TO PRODUCE ANY DRIZZLE SO LEFT THAT OUT.
ENTER THE TEMPERATURE PROBLEM. TEMP FORECASTS FOR THIS WEEKEND HAVE
EXTREMELY HIGH BUST POTENTIAL. THE MODELS KEEP HIGHS AOB FREEZING
OVER THE SNOWPACK BUT BLAST HIGHS INTO THE 50S JUST SOUTH OF THE
SNOW LINE ON SAT. IT IS EVEN MORE DRAMATIC ON SUN WHEN HIGHS COULD
EASILY RANGE FROM NR FREEZING AT HAYS TO THE MID 60S NR THE OK
BORDER. THIS WILL BE FURTHER COMPLICATED, OR PERHAPS EXASCERBATED BY
ANY FOG/STRATUS THAT FORMS AND PERSISTS INTO THE DAYLIGHT HOURS. AT
THE SAME TIME ON SUN, THE NEXT LOW LEVEL ARCTIC AIRMASS WILL BE
OOZING SOUTHWARD THROUGH THE NORTHERN INTO THE CENTRAL PLAINS.
HOWEVER, I DON'T EXPECT TO SEE THE NEXT ROUND OF ARCTIC GETTING IN
HERE UNTIL WE GET OUT INTO THE EXTENDED. ALL THAT SAID, I HAVE
GENTLY MASSAGED THE TEMP GRIDS DOWN IN THE NORTH ON SUN, BUT
OTHERWISE LEFT THEM MOSTLY ALONE. -WRIGHT
DAYS 3-7...
OVERALL, LITTLE OR NO CHANGES PLANNED TO THE EXTENDED. BOTH THE GFS
AND ECMWF ARE IN AGREEMENT WITH RESPECT TO THE UPPER 500MB PATTERN
OUT THROUGH 108 HOURS, OR TUESDAY 15 DEC AT 12Z. THEN THE ECMWF IS
CUTTING OFF THE UPPER LOW NEAR WESTERN OLD MEXICO, WHILE THE GFS
SWEEPS THE OPEN WAVE THROUGH THE FLOW, WITH THE MAIN WEAK DYNAMICS
TO OUR SOUTH. SO EITHER WAY OR SOLUTION, NO PRECIP IS IN SIGHT FOR
DDC'S CWA. A RATHER STRONG COLD FRONT WILL PASS SOUTH ON SUNDAY
NIGHT, DROPPING OUR HIGHS MONDAY SIGNIFICANTLY, SOME 25 TO 35
DEGREES COLDER THAN ON SUNDAY. THE NORTHERN COUNTIES OF ELLIS AND
TREGO WILL NOT LIKELY EVEN RISE OUT OF THE TEENS MONDAY, WITH THIS
COLD PUSH DIVING SO FAR SOUTH. TUESDAY SHOULD BE A DAY OF SLIGHT
MODERATING TEMPERATURES, RISING MAX TEMPS TO NEAR 20 DEGREES IN MY
NORTH AND THE LOWER 30S IN MY SOUTH. WEDNESDAY AND THURSDAY WILL
SEE A WARM FRONT PUSH THROUGH TO THE NORTHEAST BEHIND A STRONG
SOUTHWEST FLOW AT THE LOWER LAYERS. THIS SHOULD RAISE MAX
TEMPERATURES WEDNESDAY INTO THE UPPER 30S ACROSS OUR EXTREME
NORTHEAST AND RANGE TO AS HIGH AS 50F IN OUR SOUTHWEST. THE 50S
SHOULD OVERSPREAD ALL BUT THE CURRENT SNOW PACKED AREAS OF OUR CWA
THURSDAY, WITH A GRADIENT FROM THE MID 40S IN THE NORTHEAST AND EAST
TO THE PERHAPS THE MID 50S IN THE WEST. NO PRECIPITATION IS IN THE
FORECAST DUE TO THE NEAR ZONAL FLOW ALOFT WITH JUST WEAK MINOR
RIPPLES OF UPPER WAVES PASSING WEST TO EAST. THESE MINOR UPPER
WAVES WILL BRING COME CLOUD COVER AS THEY MOVE ACROSS, BUT NOT
ENOUGH DYNAMICS TO PRODUCE ANY PRECIPITATION.
&&
.AVIATION...
VFR SKY AND VSBY FOR THE NEXT 24 HOURS FOR ALL TAF SITES. CIRRUS
CLOUDS WILL BECOME BKN TO OVC AFTER 00Z, BUT AT 20,000 FEET OR
HIGHER. LIGHT SOUTH WINDS WILL GO LIGHT AND VARIABLE AFTER 00Z.
TOWARD MORNING, STRATUS WILL MOVE IN FROM THE SOUTH AT AROUND
OVC010-015, AND SOME FOG REDUCING VSBYS TO 2-3SM IN BR. WILL UPDATE
THE HYS TAF FOR NOW IN THE EXTENDED PARTS OF THE TAF PERIOD, AND LET
LATER SHIFTS UPDATE DDC AND GCK IF REQUIRED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 17 43 20 55 / 0 0 0 0
GCK 15 42 17 53 / 0 0 0 0
EHA 22 53 28 59 / 0 0 0 0
LBL 18 52 24 62 / 0 0 0 0
HYS 13 33 15 34 / 0 0 0 0
P28 22 45 25 52 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FN34/12/12
