FXUS63 KOAX 262014
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
214 PM CST WED JAN 26 2011
.SHORT TERM...TONIGHT THROUGH SATURDAY
PACIFIC AIR STILL ON TRACK TO OVERSPREAD MID MO VALLEY NEXT FEW
DAYS. MILDEST STILL ON TRACK FOR FRIDAY...AS A STRONGER SHORT
WAVE TROUGH MOVES FAVORABLY OVR UPPER RIDGE ACRS SRN CANADA AND
TWD NRN MN. TEMPERATURES CONTINUE TO BE THE MAIN FORECAST CONCERN
BOTH DURING THE MODERATION AND THEN COOLING BHND TROUGH ON
SATURDAY. MOISTURE APPEARS IT WILL REMAIN MAINLY LIMITED TO
EITHER BLYR OR CIRRUS LVL...OTHER THAN RELATIVELY SHORT LIVED NARROW
MID LVL BANDS THAT PIVOT THROUGH. THUS FORECAST THROUGH SATURDAY
WILL REMAIN DRY.
FOR TONIGHT...THIN STRATUS DECK...WHICH WAS BETWEEN H925 AND H950
PER 12Z OAX SOUNDING...CONTINUES SHIFTING EWD/ERODING AS WINDS AT
THOSE LVLS BACK THROUGH EVENING. THESE WINDS THEN INCREASE BY THU
AM. HOWEVER...BEFORE THEN ENOUGH DECOUPLING COULD ALLOW EVENING
LOWS SERN ZONES TO DROP BELOW COLDER MAV GUIDANCE AS CLOUD DECK
HAS KEPT SOME OF THAT AREA IN LOW 20S THIS AFTN. BETTER MIXING
EXPECTED THU...AND PER 12Z GFS/ECMWF EVEN BETTER ON FRI...AS SFC
BOUNDARY CROSSES CWA EACH DAY SHIFTING WINDS TO NWRLY. NAM WAS A
LITTLE SLOWER WITH FRIDAY/S PASSAGE AND THUS ITS FCST SFC WINDS
WERE MORE SWRLY AND LIGHTER THAN IDEALLY WOULD LIKE TO SEE EVEN
THOUGH ITS NUMERICAL GUIDANCE WAS WARMER THAN MAV. BOTH GFS AND
NAM FCST QUITE A BIT OF BLYR RH LINGERING THU AND FRI...BUT THIS
COULD BE MORE OF A MODEL PHYSICS ISSUE AS SNOW COVER IN MODEL
KEEPS SFC TEMPS FM RISING WHILE HIGHER DWPTS ASSOCD WITH PAC AIR
STREAMS SEWD. THUS LOW CLOUDS NOT EXPECTED TO BE QUITE AS
WIDESPREAD THU/FRI AS TDA. THIS NOTION WAS BACKED TO SOME DEGREE
BY SREF PROBABILITY FOR CIGS BLO 3K FEET WHICH WERE FAIRLY LOW FOR
NEBR COUNTIES AND MARGINAL FOR IA COUNTIES AND EVEN THEN MAINLY
NIGHTTIME. THUS WL AGAIN TRY TO GO FOR A GENERALLY PCLDY SKY
FORECAST THU AND FRI TO ACCOUNT FOR EITHER CI OR PASSAGES OF MID
CLOUDS. GENERALLY LEANED CLOSER TO NAM GUIDANCE FOR MAX TEMPS DUE
TO MIXING EXPECTED THU AND THEN MIXING + INCREASE IN LOW LVL TEMPS
FORECAST BY BOTH MODELS FOR FRI. BOOSTED WINDS SOME...SPCLY FRI
AFTN...BHND SECOND BOUNDARY AS LATE AFTN COLD ADVCTN BEGINS
WORKING INTO NRN ZONES. WITH WINDS OFF THE SFC STRONGER DURING THE
NEXT FEW NIGHTS COMPARED TO THIS MORNING...AND COOLER AIR SHOVED
EWD...CONFIDENCE NOT HIGH ENOUGH TO MENTION FOG OUTSIDE OF AN
EVENING MENTION TNGT SERN ZONES. ALTHOUGH WITH LONG NGTS AND SNOW
PACK SOME COULD EASILY FORM AGAIN BY EACH MORNING.
SFC FLOW TURNS MORE NRLY BHND SECOND BOUNDARY ON SATURDAY LIMITING
MIXING WITH POSSIBLY AN INCREASE IN LOWER CLOUDS AS WELL AS CANADIAN
AIR BACKS INTO ERN NEBR/SWRN IA. HOWEVER...COLDEST AIR WILL WAIT
TILL DVLPG SUN/MON SYSTEM BEFORE OVERSPREADING CWA SO ATTM DID NOT
STRAY TOO FAR FM THE NEAR NORMAL NUMBERS FCST FM MEX.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
MAIN FORECAST CHANGE WAS TO INTRODUCE SNOW TO SUNDAY NIGHT THRU
MONDAY AND TRENDED TEMPS COLDER INTO MID WEEK.
PERIOD BEGINS WITH WEAK UPPER RIDGE OVER THE CENTRAL CONUS WHILE
UPPER TROF BEGINS TO CUT ACROSS THE PACIFIC NORTHWEST COAST. MODEL
TRENDS/HPC FAVOR THE ECMWF ENSEMBLE MEAN WHICH RESEMBLES CANADIAN
ENSEMBLE MEAN AND NAEFS MEAN. THIS BEING SAID...UPPER TROF IS
FORECAST TO DIG ACROSS THE ROCKIES AND INTO THE SRN/CNTRL PLAINS
EARLY NEXT WEEK. HAVE NOT FOLLOWED 12Z GFS SOLUTION OF SPLITTING
ENERGY...KEEPING A CLOSED LOW OVER THE SWRN US. POTENTIAL IS
LOOKING BETTER FOR ACCUMULATING SNOW MONDAY AND MONDAY NIGHT SO HAVE
INTRODUCED LOW CHANCE POPS. EVOLUTION OF SFC FEATURES REMAINS
SOMEWHAT UNCERTAIN ON TIMING SO AM NOT GOING TOO HIGH WITH POPS FOR
NOW. IF INVERTED SFC TROF SETS UP AS 00Z ECMWF INDICATES...REGION
COULD BE IN FOR ANOTHER ROUND OF SNOW. WILL NOT GET TOO CARRIED AWAY
WITH POPS JUST YET...BUT POTENTIAL IS CERTAINLY THERE.
BEHIND THIS SYSTEM...1040+ SFC HIGH MOVES SOUTH ACROSS THE HIGH
PLAINS BRINGING A SLUG OF ARCTIC AIR ALONG WITH IT. HAVE TRENDED
TEMPERATURES DOWN MONDAY NIGHT THRU WEDNESDAY.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
THE IFR/LIFR CIGS THAT DEVELOPED OVER ERN NEB THIS MORNING ARE
GRADUALLY SHIFTING EASTWARD AND WILL AFFECT KOMA THRU EARLY
AFTERNOON. NORTHWEST WINDS AT 6-12KTS WILL BECOME LIGHT AND
VARIABLE AFTER 00Z. A SHORTWAVE TROF MOVING THRU THE DAKOTAS INTO
MINNESOTA TONIGHT WILL BRING A WINDSHIFT THROUGH. LIGHT SOUTHWEST
WINDS WILL SWING AROUND TO THE NORTHWEST BETWEEN 12-16Z AT KOFK
THEN KOMA AND KLNK. THE H925 WINDS INCREASE TO 40KTS...SO THINK
SOME STRONGER 10 TO 20KT WINDS WILL MIX DOWN BEHIND THE WINDSHIFT.
VARIABLE MID AND HIGH LEVEL CLDS ARE FORECAST DURING THE PD. THERE
COULD BE SOME PATCHY FOG WITH MVFR VSBYS IN LOW LYING AREAS WITH THE
LIGHT WINDS AND VARIABLE CLDS AHEAD OF THE WIND SHIFT. THE RH PROGS
ARE HINTING AT SOME LOW CLDS DEVELOPING AFT 15Z...EXPANDING
SOUTHEASTWARD ACRS ERN NEB. FOR NOW INCLUDED SCT LOW CLDS AT KOFK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/KERN/ZAPOTOCNY