FXUS63 KOAX 231951
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
251 PM CDT SAT OCT 23 2010
.SHORT TERM...TONIGHT THROUGH TUESDAY.
SEVERAL STRONG UPPER DISTURBANCES TO IMPACT WEATHER IN THE SHORT
TERM. FIRST UPPER LOW WILL BE OPENING THEN FILLING THROUGH SUNDAY
AS A MUCH STRONGER PIECE OF ENERGY DIGS ACROSS ROCKIES FIRST OF
THE UPCOMING WEEK. THUS CONVECTION STRENGTH/COVERAGE THIS
EVENING FOLLOWED BY TEMPERATURES SUN INTO MON AFTN AND FINALLY PCPN
CHCS/WIND FORECAST LATE MON INTO PRESENTS A CHANGEABLE
FOCUS/CHALLENGE.
SURFACE WARM FRONT ESTIMATED TO HAVE LIFTED TO NEAR A BVN-SUX LINE
BY 20Z ALTHOUGH THAT WAS DEFINITELY SUBJECTIVE AS CASE COULD BE
MADE IT WAS A LITTLE SOUTH OF THERE. LOW LVL DRYING WAS NOTED WEST
OF MO RIVER BUT MLCAPE PER SPC MESO PAGE REMAINED MODESTLY DECENT
MUCH OF THE CWA AND WAS CONTG TO INCREASE AS OF 19Z. WHERE
CONVECTION INITIALLY DVLPS STILL SOMEWHAT IN QUESTION AS RUC NOT
DOING A VERY GOOD JOB WITH FCST ACTIVITY THIS AFTN...HAD QUITE A
BIT OVR MUCH OF OUR CWA. HRRR/4KM WRF LOOKED A LTL BETTER IN DVLPG
INITIAL ACTIVITY N OF OMA NEAR FRONT ALTHOUGH FORMER THEN DVLPD
PCPN ALIGNING SW TO NE IN FORECAST HIGHER 850 LI AXIS EARLY THIS
EVENING NEAR BIE-OMA. ALTHOUGH WILL BE WATCHING FOR CONVECTIVE
TRENDS THRU ISSUANCE TIME WILL PRBLY BE RUNNING HIGHEST POPS NRN
ZONES AS PER PREV FORECAST WHERE CU FIELD WAS THICKENING PER
LATEST VSBL STLT WITH SECONDARY MAX SERN ZONES. WL CONT ISOLD TORNADO
MENTION IN HWO...MAINLY NEAR WARM FRONT THROUGH EARLY THIS
EVENING BUT WL PROBABLY ALSO WITH ANY LONGER-LIVED SUSTAINED
SUPERCELLS THAT MANAGE TO DEVELOP THRU EVENING SE OF THERE. DRIER
AIR FORECAST TO WRAP AROUND OCCLUDING/LIFTING/WEAKENING SYSTEM
COULD PUSH SOME UPPER 40S TOWARD LNK/BIE FOR LOWS TNGT OTHERWISE
WL KEEP MID/UPPER 50S FAR E/SE. COUNTING ON ENOUGH SUNSHINE ON
SUNDAY TO MIX OUT LOWER 70S NEAR/S OF PLATTE RIVER ON SUNDAY AND
TRIMMED BACK OR DROPPED POPS SWRN CWA AS UPPER SYSTEM CONTS
WEAKENING.
DECENT LIFT FORECAST WITH NEXT TROUGH ON MONDAY...SPCLY LATE AND
RACE WL BE ON TO HOW QUICKLY WE CAN MIX OUT BEFORE CLOUDS THICKEN
WITH ITS ARRIVAL. ATTM BOOSTED READINGS MANY AREAS...SPCLY SRN/ERN
CWA WHERE 850 MB TEMPS ONLY COOL MINIMALLY SUN AND THEN HAVE
ALREADY TURNED AROUND AHEAD OF NEXT TROUGH. IF SYSTEM SLOWS UP
JUST A FEW HRS COULD SEE SOME UPPER 70S AGAIN E. VERY STRONG LIFT
FORECAST WITH THIS NEXT SYSTEM AS HGTS AND SFC PRESSURES FALL
DRAMATICALLY LATE MON. FARTHER SOUTH 12Z NAM IS OUTLIER COMPARED
TO GFS/ECMWF AND THOSE MODELS WERE FOLLOWED. ALL SUGGESTED
INCREASING POPS INTO LIKELY CATEGORY MON AFTN W AND EVENING MOST
AREAS WITH POPS THEN DECREASING LATE MONDAY NIGHT AS SYSTEM CLOSES
OFF NRN PLAINS. ALSO MENTIONED ISOLD THUNDER TO ACCOUNT FOR
INCREASING CAPE WHICH MAY BE UNDERFORECAST BY GFS. KEPT TUE DRY
THEN BASED ON GFS/ECMWF WITH TEMPS CLOSER TO MEX GUIDANCE. ECMWF
CONTD WARMER WHILE NAM MUCH COOLER WITH LINGERING PCPN. BUMPED
WINDS UP A LITTLE ABOVE GFS WHICH WOULD APPEAR TO BE A COMPROMISE
BETWEEN THE SLIGHTLY LESS WINDY ECM AND VERY WINDY NAM. WL ALSO
MENTION STRONG WINDS IN HWO THIS EVENING.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
TEMPERATURES ARE THE MAIN CONCERN THROUGH THIS PERIOD. THE HANDLING
OF THE CLOSED LOW AT THE BEGINNING OF THE PERIOD BY THE NAM AND GEM
WERE NOT PREFERRED. GENERALLY WENT WITH A BLEND OF ECMWF AND GFS...
AND KEPT THAT BLEND THROUGH DAY 7. SOME LIGHT PCPN IS POSSIBLE FROM
WEDNESDAY INTO THURSDAY IF THE GFS SOLUTION IS TAKEN AT FACE VALUE...
BUT LEFT POPS AT 14 OR LESS IN THOSE PERIODS. 00Z ECMWF KEPT PCPN
FARTHER NORTH ACROSS THE DAKOTAS AND MINNESOTA.
500 MB CLOSED LOW INITIALLY OVER THE ARROWHEAD OF MINNESOTA WILL
TRACK OFF TO THE NORTHEAST AS A RIDGE BUILDS OVER THE ROCKIES. THE
RIDGE PUSHES OUT INTO THE PLAINS ON THURSDAY INTO FRIDAY. 00Z ECMWF
SEEMED A BIT TOO AGGRESSIVE WITH SYSTEM OVER THE SOUTHWESTERN U.S.
TOWARD SATURDAY. 12Z ECMWF HAD MORE OF AN OPEN WAVE.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
AN UPR LEVEL STORM SYSTEM OVER WRN NEB WILL GRADUALLY WEAKEN AND
SHIFT EASTWARD THRU 18Z SUN. SOME ISOLATED TSRA MAY DEVELOP LATE
THIS AFTERNOON OR EARLY THIS EVENING HOURS IN THE VCNTY OF
KOMA...HOWEVER DUE TO THE UNCERTAINTY OF DEVELOPMENT DID NOT MENTION
IN 18Z TAFS. SOUTHEAST WINDS AT VARIABLE SPEEDS OF 10 TO 20KTS AT
TIMES GUSTING TO 27KTS WILL DECREASE TO UNDER 10KTS BTWN 24/00Z AND
02Z. LATER TONIGHT...MVFR CIGS ARE EXPECTED TO PUSH INTO ERN NEB
WITH SOME LOCAL IFR/LIFR BY AFT 10Z AT KOFK. CIGS SHOULD IMPROVE AFT
15Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/MILLER/ZAPOTOCNY