FXUS63 KOAX 100949
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
349 AM CST FRI DEC 10 2010
.DISCUSSION...
MAIN FORECAST CHALLENGE DEALS WITH QUICK MOVING SYSTEM THAT WILL
BRING SHARPLY COLDER READINGS AND PROBABLE PRECIPITATION MIX...
DEPENDING ON TIMING OF FRONT...FRI NGT/SAT. ALTHOUGH ATTM AMOUNTS
LOOK LIGHT.
EARLY MORNING STLT IMAGERY SHOWED AFOREMENTIONED WX MAKER WAS
PUNCHING TOWARD NRN ID AS OF 09Z. SYSTEM SHOULD BRING QUICKLY
FALLING SFC PRESSURES TO CWA AS SFC LOW DEEPENS ALONG SD/NCNTRL
NEBR BORDER BY 00Z SAT. THIS SHOULD ALLOW WARM FRONT TO DVLP/LIFT
TO NEAR NERN NEBR/NWRN IA BORDER THIS AFTN WITH THICKENING MID
CLOUDS ALONG AND PROBABLY SW OF BOUNDARY AS ISENTROPIC UPGLIDE
INCREASES. INITIAL DRYNESS OF LOWER LVLS OF AMS COULD PRECLUDE
ANY MEASURABLE PCPN THIS AFTN...BUT MID LVL LAPSE RATES STEEPEN
AND FORCING IS STRONG ENOUGH THAT DECIDED TO INCLUDE SLGT CHC POPS
NERN ZONES LATE THIS AFTN. ALSO BOOSTED TEMPS NEAR AND S OF
HIGHWAY 30 TO AROUND THOSE REACHED ON THURSDAY. COUNTING ON WARM
ADVCTN OVERCOMING A LTL LESS FAVORABLE MIXING WIND DIRECTION AND
THAT MID CLOUD CIGS WL HOLD OFF TILL LATER IN AFTN.
FOR TNGT/EARLY SAT 00Z GFS REMAINS THE SLIGHTLY FASTER OUTLIER
WITH SFC LOW TRACK COMPARED TO ECMWF/NAM WHICH WERE FOLLOWED FOR
TIMING OF POSSIBLE PCPN CHANGEOVER. HOWEVER...EVEN NAM ALLOWED
ARCTIC FRONT TO QUICKLY CATCH UP TO CANADIAN/PACIFIC FRONT THAT
PRECEDES IT AND THUS LOWERED LOWS/DWPTS TNGT AND SOME HIGHS FOR
SATURDAY. TRIED TO KEEP NON-DIURNAL TEMP TRENDS IN PLACE. WITH
STEEP LAPSE RATES ALONG AND TRAILING FIRST FRONT CAN NOT RULE OUT
AN ISOLD RUMBLE OF THUNDER BUT ATTM JUST CHANGED R- TO RW- FOR
THIS EVENING. ALSO IT APPEARED TEMP PROFILES COULD SUPPORT LIQUID
A BIT LONGER UNTIL ARCTIC BOUNDARY CATCHES UP TO FIRST FRONT LATE
TNGT BASED ON NAM. NONETHELESS MOST AREAS COULD SEE A BRIEF
ZR...OR IP BASED ON STEEPER LAPSE RATES...THREAT IN TRANSITION
FROM RAIN TO SNOW. UPPED POPS NERN ZONES THIS EVENING WITH STEEPER
LAPSE RATES IN PLACE. STRONG WINDS ON SATURDAY WILL BLOW ANY SNOW
THAT DOES FALL AROUND AND INCLUDED BLOWING SNOW FOR NERN ZONES
WHERE SOME 1 INCH ACCUMULATIONS COULD FALL. NO ADVISORY ATTM AS
BETTER FORCING AND WARMER AIR ADVECTION ALOFT OCCURS TO OUR NE AS
SYSTEM MATURES...BUT WILL MENTION RETURN TO WINTRY WX IN HWO. WL ALSO
MENTION WIND CHILL VALUES THAT COULD REACH ADVISORY CRITERIA BY
SUN MORNING AS LOWS FALL TO NEAR OR A LITTLE BELOW ZERO...WHICH
WAS AN ADJUSTMENT DOWNWARD FM PREV FCST.
SEVERAL WEAK WAVES THAT WL MOVE ACRS NRN PLAINS FIRST OF NEXT
WEEK COULD AID/TAP MODEST WRM ADVCTN AND BRING ADDITIONAL PDS OF
LGT SNOW. ADDED SMALL POPS NRN ZONES ON MONDAY IN ADDITION TO
FLURRY MENTION ELSEWHERE. A REPEAT COULD OCCUR TUESDAY AS WELL IF
00Z ECMWF/GFS ARE CORRECT. ALTHOUGH NO PCPN WAS ADDED TO TUESDAY
ATTM...DID TRIM MAX TEMPS BACK A CATEGORY OR SO...SPCLY ERN
ZONES...TO ACCOUNT FOR INCREASED CLOUD COVER AFTER PARTIAL
CLEARING PSBL MON NGT ALLOWS READINGS TO FALL INTO SINGLE
DIGITS/TEENS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THRU 11/06Z WITH
A MID DECK OVER MUCH OF THE REGION. DEEPER SATURATION AND THUS LOWER
CIGS ARE LIKELY RIGHT AFTER 06Z WHICH WILL BE ADDRESSED IN NEXT TAF
ISSUANCE. AS STORM SYSTEM BEGINS TO APPROACH THE REGION FROM THE
NORTHWEST THIS EVENING...SOME LIGHT RAIN IS POSSIBLE AFTER 00Z AT
KOFK. HAVE NOT INCLUDED IN 06Z TAFS BUT MAY NEED TO CONSIDER A
PROB30 GROUP FOR 12Z TAF ISSUANCE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/KERN