000
FXUS63 KEAX 032051
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
251 PM CST WED DEC 3 2008
.DISCUSSION...
SNOW BAND CONTINUES TO DIMINISH OVER THE EXTREME NERN CWA AS THE
SHORTWAVE TROUGH OVR MO SHEARS RAPIDLY NE. MUCH DRIER AIR WAS
SURGING SE INTO THE CWA WITH BRISK NW WINDS. WINDS TO DIMINISH
TNGT...AND WITH MOSTLY CLR SKIES...TEMPS TO DROP MAINLY IN THE TEENS.
COLDEST TEMPS WILL BE OVER THE FRESH LIGHT SNOW COVER OVER NRN MO.
OTHERWISE...MODELS CONTINUE TO INDICATE A COUPLE OF WK SHORTWAVE
TROUGHS TO AFFECT THE AREA THURSDAY NIGHT AND LATE FRIDAY. GIVEN WEAK
TO NIL FORCING WITH EACH AND MEAGER MOISTURE...EXPECT ONLY AN INCREASE IN
CLOUD COVER...MAINLY ACR THE SRN CWA THURSDAY NIGHT WITH A FEW
FLURRIES PSBL FOR FRIDAY NIGHT ACROSS NRN MO. DOWNSLOPE FLOW AHEAD OF
THE FRIDAY NGT SHORTWAVE WILL ONCE ALLOW FOR A REBOUND IN TEMPS ON
FRIDAY.
DB
MEDIUM RANGE (SAT-WED)...
FOR THE WEEKEND...MAIN CONCERNS DEAL WITH TEMPERATURES BEHIND
CLIPPER SYSTEM. STRONG PLUNGE OF COLD AIR IS PROGGED TO FALL IN
BEHIND UPR TROUGH ON SATURDAY. CURRENT FCST SEEMED TO HANDLE THIS
WELL...SO FEW CHANGES MADE TO SATURDAY HIGHS. QUESTIONS WILL ARISE
TO SATURDAY NIGHTS LOW TEMPS. MODELS CONTINUE TO ADVERTISE SLIGHTLY
DIFFERENT TRAJECTORIES OF SFC HIGH PRESSURE AS IT DROPS OUT OF
MANITOBA. CORE OF THIS COLD AIR MAY JUST SNEAK TO THE EAST OF THE
CWA...KEEPING COLDEST AIR FOCUSED IN NE MO. HOWEVER...WILD CARD IN
THE MIX IS THE AMOUNT OF MID-LVL CLOUD COVER INDUCED BY WAA TO THE
WEST. HAVE CAUTIOUSLY LOWERED MINS BY A DEGREE OR TWO ACROSS THE
CWA...HOWEVER POTENTIAL EXISTS FOR A LARGE SPREAD FROM W-E OVER THE
AREA. EXPECT MODERATING TEMPS ON SUNDAY...HOWEVER ESE TRAJECTORY
MAY LIMIT TEMPERATURE CLIMB.
SIMILAR THOUGHTS AS YESTERDAY IN REGARDS TO OVERALL PRECIPITATION
CHCS FROM THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK. MEDIUM RANGE
MODELS CONTINUE TO OSCILLATE IN DEGREE OF UPR RIDGING WEST OF THE
CONUS BY SUNDAY WITH THE PAST TWO RUNS OF BOTH THE EC AND GFS MUCH
DIFFERENT FROM EACH OTHER. HOWEVER...12Z ECMWF HAS MADE A
SIGNIFICANT JUMP TOWARDS THE OPERATIONAL GFS AND GEFS
SOLUTIONS...BRINGING A RATHER PROGRESSIVE S/W TROUGH INTO THE
CENTRAL PLAINS ON MONDAY. HOWEVER...AS EXPECTED THE DEPTH AND SPEED
OF THIS TROUGH STILL VERY MUCH IN DOUBT. ATTM...PREFER A BLEND OF
THE 12Z ECMWF/GFS SOLNS FOR THE BEGINNING OF NEXT WEEK. PROGGED UPR
JET STRUCTURE WOULD SUPPORT THE FORMATION OF A SLIGHTLY DEEPER AND
FURTHER WEST TROUGH AS INDICATED BY THE 12Z GFS. THIS IS BACKED UP
BY SEVERAL ENSEMBLE MEMBERS OF THE GEFS. HOWEVER...THE IDEA OF A
FORMATION OF A SEPARATE SOUTHERN STREAM PIECE OF ENERGY AT THE BASE
OF THE TROUGH AND ITS PHASING WITH THE NORTHERN STREAM (I.E. GFS)
HAS LITTLE SKILL IN BEING FCST 6 DAYS OUT. ALL-IN-ALL STATUS
QUO ON POPS FOR MON/MON NIGHT...LITTLE HAS SWAYED ME TO INCREASE OR
DECREASE AS COMBINATION OF ISENTROPIC LIFT AND PACIFIC MOISTURE
FETCH SHOULD BE ABLE TO PRODUCE LIGHT PRECIP IN THE AREA. REGARDLESS
OF SOLN...COLDER AIR SHOULD FILTER IN BY TUESDAY...HAVE LOWERED
READINGS A FEW DEGREES.
MD
&&
.AVIATION...
FOR THE 18Z TAFS...A BRIEF PERIOD OF MVFR/IFR SNOW IS EXPECTED UNTIL
19Z WITH RAPIDLY IMPROVING CONDITIONS AFT 19Z AS DRIER AIR SPREADS
SE. THE STRONG NW WINDS WILL DECREASE THIS EVENING WITH VFR
CONDITIONS EXPECTED FM MID-AFTERNOON THROUGH THURSDAY MORNING.
DB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$
