000
FXUS63 KOAX 140450
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1150 PM CDT THU JUN 13 2013

.AVIATION...

06Z TAFS FOR KOMA...KLNK...KOFK.

VFR CONDITIONS SHOULD OCCUR AT ALL THREE SITES OVERNIGHT. SOME
SHRA AND TSRA ARE EXPECTED TO DEVELOP OVER PARTS OF EASTERN
NEBRASKA BETWEEN ABOUT 10Z AND 12Z THEN AFFECT MAINLY KOFK AND
KOMA IN THE MORNING. CEILINGS WITH THIS ACTIVITY WOULD BE MAINLY
ABOVE 4000 FEET...BUT SOME MVFR CEILINGS AROUND 2500 FEET ARE
POSSIBLE. SOUTHERLY WINDS WILL INCREASE AND BECOME GUSTY BY MID
TO LATE MORNING.

TSRA SHOULD INCREASE OVER THE REGION MID TO LATE AFTN. INCLUDED A
PROB 30 GROUP FOR THIS AT KOFK...BUT LEFT OUT FOR KOMA AND KLNK
AT HIS TIME DUE TO UNCERTAINTY OF COVERAGE.

MILLER

&&

.PREV DISCUSSION... /ISSUED 920 PM CDT THU JUN 13 2013/

UPDATE...

BAND OF PCPN THAT WAS MOVING THROUGH THE AREA THIS AFTERNOON AND
EARLY EVENING HAS MOVED EAST OF THE FORECAST AREA AS OF 9 PM SO
CLEANED UP ZFP WORDING FOR THAT. EXPECT THAT PCPN WILL PROBABLY
HOLD OFF MOST AREAS OVERNIGHT...BUT SOME CHANCE BY 3-4 AM CDT.
01Z HIGH RESOLUTION RAP AND 00Z NAM INDICATE THIS TREND. MADE A
FEW MINOR CHANGES TO POPS IN THE MORNING. OTHERWISE FEW IF ANY
CHANGES MADE BEYOND THE TONIGHT PERIOD.

MILLER

PREV DISCUSSION... /ISSUED 308 PM CDT THU JUN 13 2013/

DISCUSSION...

THUNDERSTORM COMPLEX...INITIALLY PROBABLY ROOTED NEAR 600 MB PER
LBF/OAX 12Z SOUNDINGS...CONTINUED WORKING INTO FORECAST AREA THIS
AFTERNOON DESPITE LACK OF LOW LEVEL JET/INSTABILITY SUPPORT. THIS
HIGHLIGHTS UNCERTAINTIES THAT WILL EXIST IN FINE-TUNING
THUNDERSTORM CHCS AND TIMES THROUGH THIS WEEKEND AND IS THE
PRIMARY FORECAST CONCERN.

CURRENT RADAR TRENDS/LATEST RAP FCST WOULD TAKE THIS AREA OF
CONVECTION OUT OF ERN ZONES BY AROUND 02Z WITH A PROBABLE PRECIP
LULL UNTIL CONVECTION DEVELOPING TO OUR WEST APPROACHES OR
DEVELOPS INTO ZONES LATER TONIGHT. MADE SOME ATTEMPTS AT
ADJUSTING HOURLY GRIDS TO REFLECT THIS TREND TONIGHT.
HOWEVER...AFTER THAT RELUCTANT TO REMOVE OR LOWER TOMORROW MORNING
POPS VERY MUCH...ESPECIALLY CNTRL/NE ZONES AS 00Z/12Z ECMWF AND
12Z GFS CONTINUED TO DEVELOP QPF OVER THE NERN FA IN 12-18Z PD.
SINCE THIS AREA WILL BE ON NOSE OF THE MOISTURE/INSTABILITY RETURN
NOTED BY STRONG H85 THETA E ADVECTION IN 12Z-15Z PERIOD PER
NAM...LEFT IN LIKELY MORNING POPS NERN ZONES. ALTHOUGH THERE COULD
BE A MIDDAY LULL IN THE ACTIVITY...THIS THETA ADVECTION INCREASES
AGAIN IN THE AFTERNOON. THUS CANNOT REALLY SAY WHETHER OR NOT
CONVECTION WILL COMPLETELY DIE OUT...WHICH HAS BEEN THE CASE TODAY
AND WAS A FEW DAYS AGO AS WELL. SFC BASED DWPT RETURN PER NAM/GFS
PROBABLY TOO HIGH THUS SFC BASED CAPE FORECAST ALSO TOO HIGH
FRIDAY...BUT WITH BOUNDARY IN AREA AND UPPER WAVE LIFTING INTO
NERN MT...SOME SEVERE THREAT WILL PROBABLY EXIST. HOWEVER...
COVERAGE PROBABLY DICTATED BY EFFECTIVENESS OF CAP WHICH WILL BE
TRYING TO BECOME ESTABLISHED...ESPECIALLY SRN ZONES...OR DEBRIS
CLOUDS/PCPN FROM ANY MORNING ACTIVITY NE. AT THIS TIME MADE
LITTLE/NO CHANCES TO MAX TEMPS WHICH WILL LIKELY NEED ADJUSTING AS
AMOUNT OF DEBRIS BECOMES APPARENT.

WITH BOUNDARY REMAINING OVER AREA SATURDAY AND POSSIBLY SUNDAY...
AND CNTRL PLAINS CONTINUING ON SRN END OF WESTERLIES OF SRN
CANADIAN LOW...MODESTLY HIGH POPS WARRANTED INTO SUNDAY. ALTHOUGH
AGAIN WOULD GENERALLY THINK CENTROID OF MCS ACTIVITY ON SYNOPTIC
SCALE COULD SHIFT SOUTH EACH DAY THUS HIGHER CHCS WOULD APPEAR TO
SHIFT INTO SRN ZONES BY SUNDAY/SUNDAY NIGHT. WITH ERLY FLOW
SETTING UP SATURDAY BEHIND EXPECTED MCS TOMORROW NIGHT...LEANED
TOWARD COOLER NAM FOR MAX TEMPS. NO CHANGES TO SUNDAY MAX TEMPS AT
THIS TIME.

DRIER WEATHER STILL ON TAP MONDAY AND PROBABLY TUESDAY AS WELL AS
NWRLY FLOW SENDS HIGH PRESSURE THROUGH ERN PLAINS AND FORECAST WAS
MOSTLY DRY. AFTER THAT...RETURNING MOISTURE WILL BRING INCREASING
TSTM RISK THRU END OF WEEK ALTHOUGH FOR THE TIME BEING KEPT MOST
POPS IN LOWER CHC RANGE.

CHERMOK

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$