FXUS63 KEAX 250551
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1150 PM CST THU DEC 24 2009
...UPDATED AVIATION...
.DISCUSSION...
/533 PM CST THU DEC 24 2009/
...BLIZZARD AND WINTER STORM WARNINGS IN EFFECT AS DANGEROUS WINTER
STORM SYSTEM APPROACHES...
POTENT WINTER STORM NOW ONGOING ACROSS PORTIONS OF THE CENTRAL AND
SOUTHERN PLAINS INTO THE MIDWEST WITH VERY IMPRESSIVE STRUCTURE
EVIDENT VIA LATEST WATER VAPOR IMAGERY. PV ANOMALY NOW DIVING SOUTH
INTO THE NORTHERN PLAINS WILL BEGIN TO MERGE WITH THE SOUTHERN
STREAM FEATURE OVERNIGHT AS IT LIFTS NORTHWARD INTO CENTRAL
MISSOURI. HOWEVER...AS THIS OCCURS SIGNIFICANT DEEPENING OF THE
SOUTHERN STREAM SHORT WAVE TROUGH WILL TAKE PLACE...LIKELY REACHING
MAXIMUM INTENSITY AS IT TRANSLATES ACROSS CENTRAL AND NORTHERN
MISSOURI.
ATTM...LARGE SHIELD OF PRECIPITATION ONGOING FROM NORTHERN OKLAHOMA
AND ARKANSAS INTO PORTIONS OF IOWA AND NEBRASKA. DEFORMATION BAND
WHICH DEVELOPED EARLIER THIS AFTERNOON ACROSS EASTERN KANSAS IS
BEGINNING TO WEAKEN AS ADDITIONAL PRECIPITATION PUSHES NORTHWARD AND
NEW DEFORMATION BAND DEVELOPS THIS EVENING. BIG QUESTION IS WHERE
THIS AXIS OF HEAVIER PRECIPITATION ESTABLISHES. AT THIS TIME...IT
APPEARS THIS MAY BE TAKING PLACE ALONG THE KANSAS/MISSOURI STATE LINE
AND THIS MAY ULTIMATELY BE THE PIVOT POINT AS THE SYSTEM TURNS NORTH
ACROSS MISSOURI. FREEZING LINE HAS NOW PUSHED SOUTH OF A BETHANY TO
NEVADA LINE AND WILL CONTINUE SOUTH AND EASTWARD THIS EVENING AND
OVERNIGHT. HOWEVER...IMPRESSIVE TROWAL FEATURE TAPPING DEEP GULF
MOISTURE HAS LIMITED SNOW PRODUCTION THUS FAR AS WARM NOSE HAS
CONTRIBUTED TO MELTING THROUGH THE LOWER ATMOSPHERIC COLUMN. AS A
RESULT A MIXTURE OF FREEZING RAIN AND SLEET HAS BEEN THE DOMINANT
PRECIPITATION TYPE WITHIN THE SUBFREEZING SURFACE AIR MASS. WITH
HIGHER RADAR ECHOES SHOWING UP WITHIN LATEST NORTHWARD ADVANCING
PRECIP SHIELD...PERIODS OF HEAVY SLEET OR FREEZING RAIN WILL BE
POSSIBLE THIS EVENING WITH SLEET ACCUMULATIONS UP TO A HALF INCH WITH
ISOLATED HIGHER AMOUNTS. MID LEVEL COOLING SHOULD COMMENCE OVER THE
NEXT FEW HOURS FROM WEST TO EAST ALLOWING A CHANGEOVER TO
SNOW...ACROSS EASTERN KANSAS AND WESTERN MISSOURI. AREAS FURTHER EAST
ACROSS CENTRAL MISSOURI WILL LIKELY REMAIN WITHIN THE WARM AIR LONGER
AND THUS WILL HAVE A SLOWER TRANSITION PERIOD. LOCATIONS FROM
KIRKSVILLE TO BOONVILLE MAY NOT TRANSITION UNTIL LATE TONIGHT OR INTO
THE EARLY MORNING HOURS.
FURTHER HEIGHT FALLS WILL OVERSPREAD THE AREAS OVERNIGHT AS SOUTHERN
STREAM SYSTEM SLIDES NORTH ENHANCING LARGE SCALE ASCENT ACROSS THE
AREA LEADING TO CONTINUED PRECIPITATION THROUGH THIS TIME FRAME.
PERIODS OF MODERATE TO HEAVY SNOW CERTAINLY SEEM POSSIBLE WITH AREAS
OF ELEVATED INSTABILITY POSSIBLY DEVELOPING ABOVE LOW TO MID LEVEL
WARM NOSE. OF ADDITIONAL CONCERN IS THE LIKELIHOOD OF BLOWING SNOW AS
TIGHTENING PRESSURE GRADIENT LEADS TO SUSTAINED WINDS OF 20-30MPH. IN
ADDITION...WINDS AT OR JUST BELOW THE INVERSION LEVEL EXPECTED TO
REMAIN NEAR 45-50 KTS ACROSS EASTERN KANSAS AND WESTERN MISSOURI AS
STRONG H9 TO H8 JET SHIFTS OVERHEAD. THIS MAY EFFECTIVELY MIX DOWN
AND LEAD TO GUSTS OF 35-40 MPH AT TIMES. HAVE MAJOR CONCERNS THE
HEAVY SNOW WILL COINCIDE WITH THE STRONG AND GUSTY WINDS THIS
EVENING AND OVERNIGHT CREATING REDUCED VISIBILITIES AND FURTHER
EXACERBATE HAZARDOUS TRAVEL CONDITIONS. HAVE THEREFORE UPGRADED THE
WINTER STORM WARNING TO A BLIZZARD WARNING ACROSS THE EASTERN KANSAS
AND FAR WESTERN MISSOURI COUNTIES. OTHERWISE...MAINTAINED THE WINTER
STORM WARNING ELSEWHERE WHERE AND MIX OF SLEET FREEZING RAIN AND
SNOW IS EXPECTED.
NORTHERN STREAM PV ANOMALY PINWHEELS AROUND SOUTHERN STREAM ANOMALY
AS IT OCCLUDES ACROSS CENTRAL IOWA. SYSTEM THEN BECOMES NEARLY
STATIONARY AND INCREASINGLY BAROTROPIC THROUGH THE MIDDLE OF THE
WEEKEND AND SHOULD LEAD TO PERIODIC SNOW SHOWERS WRAPPING ACROSS...AT
LEAST THE NORTHERN HALF OF THE CWA. WITH SLR ON THE ORDER OF 12-15:1
DURING THIS TIME...LIGHT FLUFFY ACCUMULATIONS MAY OCCUR FRIDAY AND
SATURDAY. OTHERWISE...COLD AIR WILL FILTER SOUTHWARD OVER THE NEXT
SEVERAL DAYS WITH COLDER READINGS EXPECTED OVER SNOW PACKED AREAS.
DEROCHE
MEDIUM RANGE (SUNDAY THROUGH THURSDAY)...
FOR THE LAST HALF OF THE FORECAST...HAVE NOT MADE TO MANY CHANGES.
DETERMINISTIC AND ENSEMBLES MODELS ALL INDICATE THAT THE WINTER
STORM WILL BE LIFTING CLEAR OF THE CENTRAL PLAINS BEGINNING
SUNDAY...AND BY MONDAY THE SYSTEM WILL HAVE SHIFTED FAR ENOUGH TO
THE NORTH AND EAST TO ALLOW A SHORTWAVE RIDGE TO MOVE ACROSS THE
CENTRAL PLAINS. SURFACE TEMPERATURES SHOULD STAY BELOW NORMAL AS A
COLD CANADIAN SURFACE HIGH OOZES ACROSS THE PLAINS STATES THROUGH
THE FORECAST PERIOD. ONLY MITIGATING FACTORS WOULD BE THE PARTLY
SUNNY SKIES AND LIGHT SOUTHEAST SURFACE WINDS. HAVE OPTED TO KEEP
TEMPERATURES HEDGED TOWARDS THE COLD SIDE AS THERE IS AN EXPECTATION
THAT WE WILL STILL HAVE SNOW ON THE GROUND ACROSS THE ENTIRE REGION
THROUGH AT LEAST THE MIDDLE OF NEXT WORK WEEK.
AS FOR ANY PRECIPITATION POTENTIAL...SUNDAY MAY STILL HAVE SOME
FLURRIES ACROSS THE REGION AS WE WILL STILL BE UNDER THE INFLUENCE
OF WRAP AROUND PRECIPITATION FROM THE WINTER STORM AS IT MOVES INTO
THE GREAT LAKES. HAVE KEPT THE GOING PUBLIC FORECAST DRY FOR THE
REST OF THE FORECAST...BUT HAVE HEDGED WITH SOME SILENT SLIGHT
CHANCE POPS FOR TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS A OPEN AND
PROGRESSIVE SHORTWAVE MOVES THROUGH THE PLAINS. STILL RATHER FAR IN
THE FUTURE TO PIN DOWN DETAILS...BUT GIVEN RECENT WEATHER
TRENDS...THE MID TO LATE WORK WEEK PERIODS OF NEXT WEEK WOULD BE THE
PREFERRED PERIOD FOR OUR NEXT WINTER WEATHER SYSTEM.
CUTTER
&&
.AVIATION...
BAND OF LIGHT TO MODERATE SNOW HAS ALIGNED ACROSS THE TERMINAL
CORRIDOR...AND WILL REMAIN QUASI-STATIONARY THROUGH ABOUT 12Z. BAND
OF SLEET WAS TRYING TO WORK WEST TOWARDS THE STATE LINE...HOWEVER
REPORTS INDICATED PRECIPITATION TYPE BECOMING ENTIRELY SNOW ONCE
THIS AREA WORKED INTO THE SERN KANSAS CITY METRO. SNOW INTENSITIES
WILL VARY FROM LIGHT TO HEAVY AT TIMES...BUT SHOULD REMAIN MOSTLY IN
THE MODERATE RANGE. CIGS/VSBY WILL OSCILLATE BETWEEN IFR AND
LIFR...THOUGH IF A MORE INTENSE BAND CROSSES ANY AIR FIELD...VLIFR
CONDITIONS WITH 1/4SM VSBYS CAN BE EXPECTED FOR SOME TIME PERIOD.
BIGGEST PROBLEM WILL BE VERY STRONG NWLY WINDS IN THE 20G35KT
RANGE...WHICH WILL MAKE IT EXTREMELY DIFFICULT TO KEEP RUNWAYS AND
TARMACS CLEAR FOR TRAFFIC.
SNOW INTENSITIES WILL DECREASE MARKEDLY AFTER SUNRISE...THOUGH
CONTINUED STRONG WLY OR NWLY WINDS WILL KEEP VSBYS IN THE IFR/MVFR
RANGE THROUGH THE DAY. PERIODS OF LIGHT SNOW SHOULD CONTINUE THROUGH
THE DAYLIGHT HOURS...AND MAY TAPER OFF AROUND SUNSET.
21
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING UNTIL 6 PM CST FRIDAY FOR MOZ007-008-016-
017-024-025-032-033-039-040-045-046.
WINTER STORM WARNING UNTIL 6 PM CST FRIDAY FOR MOZ003>006-014-
015-022-023-030-031-038-044-054.
BLIZZARD WARNING UNTIL 6 PM CST FRIDAY FOR MOZ001-002-011>013-
020-021-028-029-037-043-053.
KS...BLIZZARD WARNING UNTIL 6 PM CST FRIDAY FOR KSZ025-057-060-
102>105.
&&
$$
