Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 262349
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
649 PM CDT TUE AUG 26 2014

.SHORT TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 300 PM CDT TUE AUG 26 2014

DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST AND OVERALL
THINKING HAS NOT CHANGED MUCH THE PAST FEW DAYS...WITH DECENT
MODEL CONSISTENCY. TIMING OF TSTMS...RAIN AMOUNTS AND AXIS OF
HEAVIEST RAIN LOCATION WILL CONTINUE TO PROVIDE THE MAIN FORECAST
CHALLENGES. THE CONVECTION FORMED ABOUT AS EXPECTED LAST NIGHT...
IN A GENERAL SENSE...BUT I DID NOT THINK WE WOULD SEE A MAX AMOUNT
OF OVER 7 INCHES. THE AMOUNTS OVER 2.5 INCHES WERE IN A FAIRLY
NARROW BAND.

LARGE SCALE FEATURES FROM THE 12Z UPPER AIR PLOTS INCLUDED THE
FOLLOWING. AT 300 MB...TWO MAIN JET SEGMENTS WERE NOTED. THE FIRST
WAS DIGGING S/SW FROM WRN NV (80 KNOTS) AND THE OTHER WAS PUNCHING
EWD ACROSS CNTRL MN (100 KNOTS). ONLY WEAK 12 HOUR HEIGHT FALLS WERE
SEEN AT 500 MB...OVER CA AND OVER SWRN CO/NWRN NM. THE CLOSED LOW
WHICH HAS BEEN OVER THE WRN UNITED STATES BECAME MORE ELONGATED AND
SHIFTED A BIT S. WATER VAPOR SHOWED THE MAIN CHUNK OF ENERGY OVER
SRN NV EARLY THIS AFTN. AT 700 MB...THE MOIST AXIS SEEMED TO HAVE
THINNED A BIT OVER THE CNTRL PLAINS AND MOST OF THE HIGHER MOISTURE
AT THIS LEVEL WAS LOCATED IN CO/AZ/NM. THE NEARLY STATIONARY LOW
LEVEL FRONT WAS STILL DOWN ACROSS KS AND MO. COOL HIGH PRESSURE
WAS OVER THE DKTS AND MN.

TONIGHT...IT SEEMS THAT CONVECTION MAY GET GOING MAINLY AFTER 05Z.
WILL KEEP SOME LOW POPS GOING THIS EVENING...THEN RAMP THEM UP VERY
QUICKLY. LOW LEVEL JET TONIGHT SEEMS A BIT WEAKER...BUT MODEL POINT
FORECAST SOUNDINGS AND PLAN VIEWS SHOW PRECIPITABLE WATER (PW)
VALUES INCREASING TO OVER 2 INCHES TONIGHT. STRONGEST FORCING AND
SUPPORT ARE IN THE SAME GENERAL AREA AS LAST NIGHT. WITH MORE SOIL
MOISTURE NOW AND A SIMILAR QPF POTENTIAL POSSIBLE TONIGHT...
DECIDED A FLASH FLOOD WATCH WAS APPROPRIATE. NOT ALL AREAS WILL
SEE FLOODING...BUT THREAT IS HIGH ENOUGH TO INCLUDE HEADLINES.
SOME PCPN SHOULD LINGER INTO MID MORNING WEDNESDAY...SO DECIDED
TO RUN THE WATCH FROM 03Z WED TO 15Z WED. LOOK FOR LOWS TONIGHT IN
THE 60S...COOLEST NRN ZONES AND WARMEST SRN ZONES.

WEDNESDAY...STORMS SHOULD TEND TO WEAKEN THROUGH THE MORNING BUT
MAY FIRE AGAIN BY LATE AFTERNOON. MODELS SUGGEST LOW PRESSURE
WILL STRENGTHEN OVER ERN CO DURING THE DAY...THEN ATTEMPT TO LIFT
NEWD WEDNESDAY NIGHT. THIS MAY SHIFT AXIS OF HEAVIEST RAIN FARTHER
N ACROSS NERN NE IN THE EVENING AND THEN TO NRN IA/SRN MN FOR THE
EARLY MORNING HOURS OF THU. UNSETTLED CONDS ARE LIKELY TO CONTINUE
THU INTO THU NGT AS THE FRONTAL BOUNDARY LINGERS IN THE AREA WITH
MID TROPOSPHERIC TROUGH NOT MOVING EAST OF OUR AREA UNTIL SAT.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CDT TUE AUG 26 2014

THIS PERIOD GENERALLY LOOKS LESS ACTIVE...ESPECIALLY BY SAT...AND
THE 12Z MODELS WERE IN PRETTY GOOD AGREEMENT WITH THE LARGE SCALE
PATTERN ALOFT. WEAK RIDGING SHOULD BUILD INTO THE AREA FROM THE
W ON SATURDAY...BUT THIS IS SHORT-LIVED. A STRONG TROUGH WILL BE
DIGGING ACROSS THE ROCKIES OVER THE WEEKEND. IT APPEARS THIS
SHOULD BECOME MORE BROAD AND MOVE A BIT FARTHER EAST TOWARD THE
MIDLANDS BY TUESDAY. THE ECMWF...CANADIAN GEM AND THE 12Z GFS
HAVE SOME DIFFERENCES WITH THE LOW LEVEL FEATURES AND ALSO WITH
PCPN POTENTIAL. FOR NOW... GENERALLY USED A BLEND OF SOLUTIONS...
WITH A BIT MORE WEIGHT GIVEN TO THE 12Z ECMWF.

&&

.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 641 PM CDT TUE AUG 26 2014

VARIABLE CONDITIONS ARE EXPECTED DURING THE PERIOD WITH VFR
CONDITIONS INITIALLY THEN BECOMING MVFR TO IFR AS THE NEXT ROUND
OF CONVECTION INITIATES TOWARDS 06Z. CONDITIONS IMPROVE TO VFR BY
18Z ALTHOUGH OVERCAST CONDITIONS EXPECTED TO REMAIN THROUGH THE
REMAINDER OF THE PERIOD.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH WEDNESDAY
     MORNING FOR NEZ042>045-050>053-065.

IA...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH WEDNESDAY
     MORNING FOR IAZ055-056-069.

&&

$$

SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...FOBERT



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