FXUS63 KOAX 290242 AAB
AFDOAX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
842 PM CST SUN NOV 28 2010
.UPDATE...
UPDATED TO ADJUST START TIME OF DRIZZLE A LTL TNGT.
&&
.DISCUSSION...
LARGE UPPER LEVEL SYSTEM CONTINUES TO TAKE SHAPE OVER ROCKIES
WITH BROAD AREA OF 100-130 M HGT FALLS AT H5 FROM LBF TO ABQ AT
00Z. SOME 850 MB MOISTURE WAS BEGINNING TO STREAM NWD WITH IT NEAR
OKC AT 00Z WITH SOME 4-5K FT CIGS DVLPG FM SERN KS INTO NERN TX.
TRAJECTORIES OF THESE CLOUDS WOULD BE MOSTLY SE OF THE CWA...BUT
SOME EXPANSION WWD EXPECTED TOWARD MORNING. IN ADDITION LOW CLOUDS
WERE STARTING TO EXPAND SEWD BHND SFC FNT THAT WAS MAKING SLOW SE
PROGRESS INTO NCNTRL NEBR AT 02Z. ALTHOUGH THIS EXPANDING AREA OF
LOW CLOUDS COULD CONTAIN SOME FREEZING DRIZZLE AS IT MOVES INTO
WRN SECTIONS OF NERN NEBR LATE TNGT...APPEARS LOWER LEVELS
ELSEWHERE BASED ON CURRENT TRENDS AND 00Z NAM WOULD STAY DRY
ENOUGH TILL 12Z OR LATER TO KEEP MOST DRIZZLE FM DVLPG UNTIL AFTER
THAT TIME PD. THUS REMOVED FM SE/ECNTRL ZONES TNGT. NEW NAM HAS ALSO
CONTINUED TREND OF ITS 18Z RUN IN BACKING OFF W/QPF AMOUNTS WITH
SYSTEM AND LOOKED MORE LIKE 12Z ECMWF. HOWEVER...NO CHANGES TO
SNOW AMOUNTS/HEADLINES FOR MON/MON NGT JUST YET SINCE 18Z GFS
STILL SUPPORTED FORECAST AND NOT COMPLETELY CONFIDENT IN NEW NAM.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 552 PM CST SUN NOV 28 2010/
UPDATE...
UPDATED TO REMOVE RED FLAG WARNING AND WIND ADVISORY.
OTHERWISE...NO OTHER CHANGES.
PREV DISCUSSION... /ISSUED 313 PM CST SUN NOV 28 2010/
SHORT TERM...TONIGHT THROUGH WEDNESDAY.
WL CONTINUE WIND ADVISORY AND RED FLAG WARNING HEADLINES THRU 00Z
MON AS STRONG SE WINDS CONTINUE IN ADDITION TO LOW SFC DEWPOINTS.
UPPER TROF CURRENTLY DIGGING ACROSS THE FOUR CORNERS REGION WILL BE
MAIN CONCERN FOR OUR REGION OVER THE NEXT 24-36 HOURS. SIGNIFICANT
500MB HEIGHT FALLS AS SEEN ON 12Z UPPER AIR ANALYSIS OVERSPREAD A
LARGE AREA OF THE GREAT BASIN AND WL CONTINUE TO SPREAD INTO THE
CNTRL PLAINS OVER THE NEXT 24 HOURS. LEE CYCLONE OVER ERN COLORADO
WL CONTINUE TO DEEPEN IN RESPONSE TO DEEPENING UPPER TROF AND BEGIN
TO PUSH INTO WRN KS/NEB OVERNIGHT WITH STRONG CDFNT EXTENDING N/NEWD
INTO THE DAKOTAS. MAIN MISSING FACTOR ON CURRENT ANALYSIS OF
ATMOSPHERE IS MOISTURE. STRONG ISENTROPIC UPGLIDE AND SHALLOW MOIST
ADVECTION IS FORECAST TO OVERSPREAD MUCH OF SOUTH AND EASTERN CWA
DURING THE OVERNIGHT WHICH COULD PRODUCE A FEW AREAS OF DRIZZLE THRU
THE EARLY MORNING HOURS AHEAD OF THE BOUNDARY IF WE CAN INDEED GET
THE MOISTURE HERE. BEHIND THE CDFNT...PATCHY FREEZING DRIZZLE WL BE
POSSIBLE INITIALLY AS SFC TEMPS REMAIN NEAR OR BELOW FREEZING AT THE
SFC. IN FACT...OUR DIVIDING LINE BETWEEN FROZEN AND LIQUID PCPN WL
BASICALLY BE ALONG THE FRONTAL BOUNDARY.
BY MON 15Z...SFC LOW SHOULD BE CENTERED SOMEWHERE OVER OUR CNTRL
CWA. HAVE FOLLOWED MORE CLOSELY TO THE 09Z AND 15Z SREF WHICH SEEMS
TO BE A FAIRLY GOOD MATCH TO THE 12Z GFS. 12Z NAM WAS ODD MODEL OUT
AND SEEMED TOO FAR SOUTH THAN OTHER MODEL CONSENSUS IN REGARDS TO
SFC LOW/FRONT. THIS SAID...BEST LARGE SCALE FORCING FOR ASCENT WL BE
OVER NORTHEASTERN NEB MONDAY AFTERNOON AND EVENING WHERE WE SHOULD
SEE HIGHEST SNOWFALL ACCUMULATIONS OVER THE CWA. LIGHTER AMOUNTS ARE
CERTAINLY POSSIBLE ACROSS AREAS FARTHER SOUTH AS TAIL END OF
DEFORMATION ZONE/FRONTOGENESIS SWINGS THRU. OVERALL...HAVE SNOWFALL
ACCUMULATIONS RANGING FROM 1.5 INCHES IN THE NORTH TO NEAR A HALF
INCH TOWARD THE OMAHA METRO WITH LESS TOWARD THE MO/KS BORDER. DO
THINK RATIOS WL BE RATHER HIGH BY THE TIME IT ACCUMULATES OVER NERN
NEB SO HAVE GONE SLIGHTLY OVER AN INCH OF ACCUMULATION.
STRONG NW WINDS ARE EXPECTED BEHIND THE FRONT ACROSS NERN NEB
BEGINNING MON AFTERNOON AND CONTINUING INTO THE OVERNIGHT HOURS. SFC
WINDS OF 25 TO 35 MPH WITH GUSTS TO NEAR 45 LOOK POSSIBLE WITH
NEARLY 55 KTS OVERHEAD AT 850MB. ANY SNOW WL BE BLOWING AROUND SO
HAVE INCLUDED BLOWING SNOW IN NORTHERN AREAS. WIND CHILL VALUES TUE
MORNING WL RANGE IN THE SINGLE DIGITS BELOW ZERO IN OUR NORTH TO THE
SINGLE DIGITS ABOVE ZERO IN THE SOUTH.
WL GO AHEAD WITH WINTER WEATHER ADVISORY FOR PORTIONS OF OUR NORTH
BEGINNING 15Z MONDAY AND CONTINUING UNTIL 06Z TUE. THIS COULD
POSSIBLY NEED TO BE EXTENDED IN AREA AT SOME POINT...BUT FOR NOW
WL GET THE HEADLINE OUT FOR A HEADS UP ABOUT MONDAY'S
DAYTIME/EVENING MESS IN OUR NORTH WHICH BEGINS WITH FREEZING
DRIZZLE CHANGING TO SNOW AND THEN TO BLOWING SNOW. OUR BIGGEST
METRO AREAS SHOULD BE SPARED FOR MUCH OF THE WORK/SCHOOL DAY WITH
RAIN OR DRIZZLE EXPECTED...HOWEVER AFTER SUNSET WILL BE A
DIFFERENT STORY WITH RAIN CHANGING TO SNOW.
STRONG NW WINDS SHOULD SUBSIDE TUESDAY WITH FAIRLY COLD TEMPS
CONTINUING. A BIT OF WAA BY WED SHOULD BRING HIGHS BACK INTO THE
LOWER TO MID 30S.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
FLOW PATTERN AT 500 MB STARTS OUT FAIRLY FLAT ACROSS THE CONUS AT
THE BEGINNING OF THIS PERIOD...BUT A WEAK RIDGE SHOULD BE STARTING
TO BUILD OVER THE ROCKIES. THIS RIDGE MOVE EAST INTO THE PLAINS...
WHILE TROUGHS DEVELOP JUST OFF THE WEST COAST OF THE U.S. AND ALSO
FROM HUDSON BAY TO INTO THE NORTHEAST PART OF THE NATION. 12Z GFS
SHOWED A SHORTWAVE WITH SOME MID LEVEL MOISTURE MOVING THROUGH THE
AREA ON THURSDAY...BUT MOISTURE BELOW 850 MB LOOKS PRETTY LOW FOR
MEASURABLE PCPN. SO FOR NOW WILL JUST LEAVE THURSDAY DRY.
THE ECMWF CONTINUES TO SHOW A MORE ORGANIZED AND STRONGER SYSTEM
MOVING ACROSS THE NORTHERN PLAINS FRIDAY AND FRIDAY NIGHT COMPARED
TO THE GFS. PRECIPITATION CHANCES STILL SEEM BETTER TO OUR EAST AND
NORTH...SO KEPT POPS AT 14 OR LESS FOR NOW. WILL CONTINUE TO MONITOR
AND MAY ADD POPS FOR FRIDAY IF MODEL AGREEMENT IMPROVES OVER THE
NEXT FEW DAYS.
MODEL DIFFERENCES GROW EVEN LARGER NEXT WEEKEND AND EARLY NEXT
WEEK...SO FORECAST CONFIDENCE DROPS TO BELOW NORMAL WITH RESPECT
TO DETAILS THAT FAR OUT.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
SFC WINDS AND LLWS WILL BE THE PRIMARY AVIATION CONCERNS...THEN
DETERIORATING CIGS AND VSBYS AFTER 06Z.
SOUTHERLY SFC WINDS OF 25 TO 30KTS SUSTAINED WITH GUSTS 30-40KTS
WILL CONTINUE THIS AFTERNOON...THEN GRADUALLY DECREASE TO 10 TO 20
KTS AFTER 00Z. WILL CONTINUE TO MENTION LLWS AT 18050KTS TONIGHT AT
KOMA AND KLNK. A STRONG COLD FRONT WILL MOVE THROUGH LATE TONIGHT
AND MONDAY MORNING...WITH LOWERING CIGS AND VSBYS AND LIGHT
PRECIPITATION. VFR CIGS WILL CONTINUE THRU 09Z AT KOFK WITH CIGS
BECOMING MVFR AND AREAS OF IFR WITH PATCHY FREEZING DRIZZLE THEN
LIGHT SNOW. CIGS ARE EXPECTED TO BECOME MVFR BETWEEN 12-15Z A KOMA
AND KLNK AT TIMES IFR WITH LIGHT PRECIPITATION. KOMA AND KLNK
SHOULD REMAIN ABOVE FREEZING THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 9 AM MONDAY TO MIDNIGHT CST MONDAY
NIGHT FOR NEZ011-012-016>018-030>032-042.
IA...NONE.
&&
$$
KERN/MILLER/ZAPOTOCNY