736 
FXUS63 KOAX 291715
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1215 PM CDT MON APR 29 2013

.DISCUSSION...

ADDED A SLIGHT CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON IN 
FAR SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. MODEST HEATING AND
MOISTURE CONVERGENCE NEAR THE FRONT COULD LEAD TO STORM 
DEVELOPMENT BY 5 PM OR 6 PM. IF THESE DEVELOP...THEN WOULD 
LIFT NORTHEAST TOWARD CENTRAL IOWA.

MILLER

&&

.AVIATION...

18Z TAFS FOR KOMA...KLNK...KOFK.

MID LEVEL CLOUDINESS CONTINUES TO DECREASE IN COVERAGE/THIN OUT.
EXPECT SOME CLOUD DEVELOPMENT AROUND 4000 TO 5000 FEET AND SMALL
POTENTIAL FOR TSRA MAINLY AT KOMA BUT ALSO SOMEWHAT AT KLNK. DID 
NOT HAVE ENOUGH CONFIDENCE TO ADD INTO TAFS AT THIS POINT...BUT
WILL AMEND AS NEEDED. 

SOUTHERLY WINDS WILL CONTINUE OVERNIGHT AHEAD OF THE NEXT COLD
FRONT...WHICH SHOULD APPROACH KOFK TOWARD 12Z...THEN REACH NEAR
KOMA AND KLNK TOWARD 15Z.

MILLER

&&

.PREV DISCUSSION...  /ISSUED 352 AM CDT MON APR 29 2013/

DISCUSSION...

MAIN ISSUE UNFORTUNATELY IS NEXT ROUND OF CHILLY WEATHER HEADING OUR 
WAY. MODELS ARE IN GOOD AGREEMENT LARGE SCALE FLOW ALOFT WILL 
QUICKLY TRANSITION FROM ZONAL TO MERIDIONAL WHEN AN ANOMALOUS 
LONGWAVE TROF ENVELOPS THE PLAINS AND DRAWS ANOTHER CANADIAN AIR 
MASS DEEP INTO THE LOWER 48. PROLONGED BELOW NORMAL TEMPS ARE 
EXPECTED THEN HEADING INTO AND THRU THIS WEEKEND AS THE UPPER TROF 
EVOLVES TO A CLOSED CIRCULATION AND BECOMES CUT OFF OVER THE MID MS 
VLY. 

FOR TODAY...FRONTAL BNDRY EXTENDING FROM SRN MN TO WRN KS THIS 
MORNING WILL EVENTUALLY WASH OUT LATER TODAY WITH SLY FLOW SETTING 
UP IN RESPONSE TO DEEPENING SFC LOW PRESSURE IN ERN MT. ANTICIPATED 
CANADIAN AIR MASS THEN SWEEPS SWD ON TUESDAY. 

EXPECT PCPN INITIATION BY TUESDAY AFTN ALONG LLVL MOIST CONVG 
AXIS...BECOMING MORE WIDESPREAD AS FRONTOGENETIC FORCING DEEPENS.
OVERALL SYNOPTIC SCALE LIFT IS QUITE IMPRESSIVE PER BOTH THE
NAM/GFS ...AROUND 20 MICROBARS. LEADING EDGE OF COLD FRONT SHIFTS
SOUTH OF THE CWA WED MORNING. HOWEVER...POST-FRONTAL PCPN APPEARS
PROBABLE. 300-500MB QVEC CONVG SUGGEST SUSTAINED LIFT VIA DPVA
COUPLED WITH MID LYR ISENTROPIC UPGLIDE WILL CONTRIBUTE TO PCPN
ACTIVITY POSSIBLY INTO THURSDAY.

PCPN CHANCES OVER THE WEEKEND THEN ASSOCIATED WITH CUT OFF CLOSED 
UPPER LOW CENTERED OVER THE MID MS VLY. GIVEN POSITION OF THE 
SYSTEM...MAINTAINING SMALL POPS IN GOING FCST REASONABLE.

DEE

&&

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

$$