FXUS63 KLBF 082207
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
407 PM CST TUE DEC 8 2009
.DISCUSSION...
WINTER STORM IS CROSSING THE CENTRAL PLAINS AND BRINGING SNOW AND
BLOWING SNOW TO WRN AND NCTRL NEBR. MODELS IN GOOD AGREEMENT EXITING
SYSTEM FROM MOST OF FORECAST AREA SOON AFTER 06Z. THE EXCEPTION WILL
BE NORTHEASTERN COUNTIES WHERE CHCS MAY LINGER TIL 12Z. SNOW HAS
BEEN FALLING THROUGHOUT THE DAY OVER THE CWA...WITH 4.5 INCHES OF
POWDER SNOW REPORTED ALREADY HERE AT THE OFFICE. KLNX RADAR REMAINS
OUT OF SERVICE DUE TO A POWER FAILURE. SATELLITE IMAGERY INDICATES
ENHANCED SNOWFALL BANDS ROTATING FROM NWRN KS INTO SWRN NEBR FROM H7
LOW CENTER NEAR GLD KS. ALSO ENHANCED SNOWFALL IN NERN FORECAST AREA
FROM BURWELL THROUGH ONEILL. CURRENT WINTER WEATHER ADVISORY WILL
CONTINUE UNTIL 6 PM CDT FOR AREAS WEST OF VALENTINE THROUGH
STAPLETON AND GRANT WITH WIND CHILL ADVISORY IN EFFECT THEREAFTER.
PORTIONS OF NORTH CENTRAL TO THE EAST INCLUDING AINSWORTH...BASSETT
AND BREWSTER TO REMAIN IN WINTER WESTERN ADVISORY AND WIND CHILL
ADVISORY OVERNIGHT. ALL COUNTIES IN WINTER STORM WARNING WILL REMAIN
UNDER A WARNING OVERNIGHT. ALTHOUGH SNOW ACCUMULATIONS WILL DIMINISH
AND END FROM WEST TO EAST OVERNIGHT....BLOWING SNOW AND DANGEROUS
WIND CHILLS WILL REMAIN A HAZARD OVERNIGHT.
SFC WINDS SHIFT FROM NORTHEAST TO NORTH ATTM AND INCREASING TO 15 TO
30 MPH MOST AREAS. THIS IS CAUSING BLOWING AND DRIFTING IN OPEN
AREAS. EXISTING GRADIENT OVERNIGHT WILL KEEP ERN AREAS MIXED AND
LOWS FROM -5 TO -10 DEGREES BELOW. WESTERN AREAS TO BE COLDER WITH
SOME CLEARING AFTER MIDNIGHT AND LIGHT WINDS WITH LOWS -10 TO -20
DEGREES BELOW ZERO.
CONTINUED BITTER COLD TOMORROW AS BROAD UPPER TROUGH ENCOMPASSES
CENTRAL CANADA INTO THE CENTRAL U.S. HIGHS MAINLY IN THE SINGLE
DIGITS EXCEPT IN THE SOUTHWEST WHERE AROUND 10 IS POSSIBLE. LOWS
LIKELY TO EQUAL IF NOT SURPASS TONIGHTS LOWS AS WINDS LIGHT WITH
HIGH PRESSURE CENTERED ONLY A LITTLE TO THE SOUTH. LOWS FROM -15 TO
-21 BELOW MAINLY WEST OF HWY 83 AND NORTH OF INTERSTATE 80.
THEN A SLOW REBOUND OF TEMPS AS LARGE TROF SLOWLY LIFTS TO THE
EAST. SNOW PACK GOING TO KEEP TEMPS ON THE COOL SIDE AND LIKELY
BELOW GUIDANCE FOR SEVERAL DAYS. HIGHS THURSDAY IN THE TEENS AND
FRIDAY FROM LOWER 20S ERN PNHDL AND FAR SW TO MID TEENS NORTHEAST.
.EXTENDED...
SPLIT FLOW IN THE WEST EARLY IN THE WEEKEND LOOKS TO TRANSITION TO A
RIDGE EARLY NEXT WEEK...BEYOND THAT SOME DISCREPANCY WITH HOW NEXT
TROF UNFOLDS ACROSS THE WEST MID TO LATE WEEK. THE ZONAL FLOW EARLY
ON WILL LEAVE TROF ALONG THE WESTERN HIGH PLAINS WITH MAIN ARCTIC
HIGH SHIFTED TO THE ATLANTIC COAST. THIS SHOULD ALLOW FOR SOME
WARMING TO MOVE FARTHER OFF THE FRONT RANGE INTO WESTERN CWA WITH
TEMPS RANGING FROM THE UPPER 20S FAR SOUTHWEST...TO THE UPPER TEENS
IN THE NORTHEAST AS RECIRCULATED COLD AIR PROBABLY LOCKED INTO THE
EASTERN CWA ON SATURDAY. STRONGER SYSTEM WILL BE MOVING THROUGH
CENTRAL CANADIAN PROVINCES OVER WEEKEND WITH MOST MODEL GUIDANCE
LEADING TO SLOWER SOLN SIMILAR TO EURO/CANADIAN...DELAYING THE NEXT
ARCTIC FRONTAL PASSAGE TO SATURDAY NIGHT. THIS FROPA WILL DROP TEMPS
BACK INTO THE LOWER TEENS FAR NORTHEAST TO MID 20S FAR SOUTHWEST.
PRECIPITATION CHANCES ON THE LOW SIDE WITH UPSLOPE FLOW UNDERCUTTING
THE WESTERLY FLOW ALOFT. DENDRITIC LAYER FAIRLY LOW AND SHOULD BE
ENOUGH LIFT FOR LIGHT SNOW ON SUNDAY AND INTRODUCED LOW POPS ATTM
SIDING WITH HPC GUIDANCE. ARCTIC HIGH CENTERED OVER NEB MONDAY
MORNING COULD BRING ANOTHER ROUND OF BELOW ZERO TEMPS. SHOULD SEE
VERY GRADUAL WARMUP EARLY TO LATE WEEK AS WESTERN RIDGE MODIFIED TO
ZONAL FLOW AS IT MOVES OVER ROCKIES INTO PLAINS. SNOW COVER AND
STRENGTH OF WESTERLY LLVL FLOW WILL DETERMINE AMOUNT OF WARMING AND
PLAYED CONSERVATIVE SIDE ATTM KEEPING TEMPS JUST ABOVE FREEZING BY
TUESDAY IN THE WEST.
&&
.AVIATION...
IFR/LIFR CONDITIONS SHOULD REMAIN FAIRLY WIDESPREAD ACROSS WESTERN
AND NORTH CENTRAL NEBRASKA THROUGH THE LATE AFTERNOON/EARLY EVENING
HOURS. SNOW...MODERATE TO HEAVY AT TIMES...WILL BE A BIG CONTRIBUTOR
TO THE LOWER END CRITERIA AS VSBYS WILL BE AOB 1/2SM AT TIMES. NORTH
WINDS OF 15 TO 25 MPH...WITH GUSTS APPROACHING 30 MPH AT THE KLBF
AND KVTN TERMINALS THIS EVENING WILL ALSO CAUSE AREAS OF BLOWING
SNOW AND IFR VSBYS. IMPROVEMENT WILL COME FROM WEST TO EAST LATE
EVENING THROUGH THE OVERNIGHT HOURS AS THE STORM SYSTEM PROGRESSES
INTO THE LOWER MO VALLEY. EXPECT CONDITIONS TO IMPROVE TO AT LEAST
MVFR AT KLBF AND KVTN TERMINALS BY MIDNIGHT REACHING VFR BY
MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING IN EFFECT UNTIL MIDNIGHT CST /11 PM MST/
TONIGHT AND WIND CHILL ADVISORY IN EFFECT FROM MIDNIGHT CST /11 PM
MST/ TONIGHT TO 10 AM CST /9 AM MST/ WEDNESDAY FOR NEZ059-069>071.
WINTER STORM WARNING IN EFFECT UNTIL 6 AM CST WEDNESDAY AND WIND
CHILL ADVISORY IN EFFECT FROM 6 AM TO 10 AM CST WEDNESDAY FOR
NEZ010-027>029-038.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM CST /5 PM MST/ THIS
EVENING AND WIND CHILL ADVISORY IN EFFECT UNTIL 10 AM CST /9 AM MST/
WEDNESDAY FOR NEZ004-005-022>025-035>037-056>058-094.
WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 AM CST WEDNESDAY...
AND WIND CHILL ADVISORY NOW IN EFFECT UNTIL 10 AM CST WEDNESDAY FOR
NEZ006>009-026.
&&
$$
SHORT TERM...ROBERG
AVIATION/EXTENDED...13
