Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 290446
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1146 PM CDT SAT MAR 28 2015

.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 333 PM CDT SAT MAR 28 2015

ANOTHER FRONTAL PASSAGE MAY BRING LIGHT RAIN LATE TONIGHT...BUT
MILDER WEATHER IS ALREADY SHOWING ITSELF.  SUBJECTIVE 12Z UPPER AIR
ANALYSIS INDICATES PROGRESSIVE UPPER-LEVEL TROUGH AXIS IN THE
EASTERN US...WITH 500MB HEIGHT RISES FROM THE CENTRAL AND NORTHERN
PLAINS EAST TO THE GREAT LAKES. UPPER-LEVEL SHORTWAVE TROUGH WAS
NOTED IN BC/WA/OR...WITH 500MB HEIGHT FALLS UP TO 140M ASSOCIATED
WITH IT.  UPPER-LEVEL JET OF 100KT+ WRAPPED FROM THE BACK SIDE OF
THE EASTERN TROUGH AROUND ITS BASE...WITH UP TO 180KT AHEAD OF IT IN
NEW ENGLAND.  850MB TEMPERATURES WERE WARMING ACROSS THE
PLAINS...WITH STRONGEST TEMPERATURE GRADIENT NOTED FROM ND THROUGH SD/ND/KS
TOWARD OK. CONUS WAS PARTICULARLY DRY AT 850MB FOR MARCH...WITH
ONLY ONE SITE IN WA /KOTX/ WITH A DEWPOINT EVEN ABOVE 0C. SURFACE
LOW AT 19Z WAS CENTERED IN SOUTHERN AB...WITH SURFACE HIGH IN
IL/IN...AND DECENT PRESSURE GRADIENT BETWEEN.

MAIN FORECAST CONCERNS ARE FRONTAL PASSAGE TONIGHT...WINDS
TOMORROW...AND POTENTIAL FIRE WEATHER ON MONDAY.  POTENT SHORTWAVE
IN THE PACIFIC NORTHWEST EARLIER TODAY IS PROGGED TO SLIDE ACROSS
THE PLAINS TONIGHT...WITH A COLD FRONT AND WITH THE POTENTIAL FOR
RAIN.  LOWER AND MID-LEVELS ARE QUITE DRY IN THE REGION...BUT WAVE
DOES SEEM STRONG ENOUGH TO GENERATE RAINFALL TONIGHT.  GIVEN THE
WEAK INSTABILITY /UP TO AROUND 200 J/KG MUCAPE AND WEAKLY NEGATIVE
LI/...HAVE MENTIONED PRECIPITATION AS SHOWERS RATHER THAN RAIN...BUT
DID KEEP OUT THUNDER MENTION AS INSTABILITY IS QUITE WEAK.  BEHIND
THE COLD FRONT...NORTHWEST WINDS INCREASE SUBSTANTIALLY FROM LATE
MORNING TO EARLY AFTERNOON...ESPECIALLY ALONG AND NORTH OF I-80.
HAVE LOWER CONFIDENCE IN SOUTHWARD EXTENT OF ADVISORY CRITERIA
WINDS...BUT DID ISSUE A WIND ADVISORY FOR THE NORTHWESTERN HALF OF
THE CWA FOR TOMORROW.  RELATIVE HUMIDITY WILL BE ON THE LOW SIDE IN
THE AFTERNOON...BUT BELIEVE IT WILL REMAIN ABOVE RED FLAG CRITERIA
OF 20% AND HAVE KEPT FIRE WEATHER HEADLINES OUT.

WARM AIR ADVECTION GETS GOING IN EARNEST FOR MONDAY AND TUESDAY.
SOUTHWEST WINDS ON MONDAY SHOULD ALLOW FOR GOOD MIXING...WITH HIGHS
IN THE 70S ACROSS THE AREA. WITH MID-LEVELS REMAINING DRY...DO THINK
CONDITIONS ON MONDAY COULD FLIRT WITH RED FLAG IN AT LEAST PARTS OF
THE AREA.  WILL NOT ISSUE A FIRE WEATHER WATCH JUST YET...BUT WILL
MENTION POTENTIAL IN THE HWO AS CONFIDENCE IS INCREASING FOR AT
LEAST VERY HIGH FIRE DANGER.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 333 PM CDT SAT MAR 28 2015

COLD FRONTAL PASSAGE ON WEDNESDAY LOOKS MORE AND MORE LIKE IT WILL
OCCUR IN THE AFTERNOON TO EVENING...ALLOWING WARMING FOR ONE MORE
DAY AHEAD OF THE FRONT INTO THE CWA.  HAVE BOOSTED TEMPERATURES FOR
WEDNESDAY INTO THE MID TO UPPER 70S.  WITH MOISTURE FINALLY
RETURNING TO THE PLAINS AHEAD OF THE FRONT...INSTABILITY WILL
INCREASE THROUGH THE DAY.  IT IS MARCH...AND MOVING A COLD FRONT
INTO AN ADEQUATELY MOIST AND UNSTABLE AIRMASS IS USUALLY A
TRIGGER FOR THUNDERSTORMS. HAVE KEPT THUNDER WORDING FOR WEDNESDAY
AFTERNOON AND EVENING AND WILL CONTINUE TO MENTION IN HWO...THOUGH
SEVERE POTENTIAL IS STILL UNCERTAIN THIS FAR IN ADVANCE. FRONT IS
NOT TOO QUICK TO EXIT ON WEDNESDAY NIGHT...AND COULD SEE A
HEALTHY SPRING RAIN OF A QUARTER TO HALF INCH WITH THIS SYSTEM.

AFTER A DRY PART OF THURSDAY BEHIND THE FRONT...MODELS ARE
TRENDING TOWARD SOME KIND OF PRECIPITATION SPREADING ACROSS THE MO
VALLEY REGION ON THURSDAY NIGHT/FRIDAY ON THE COOL SIDE OF A MID-
LEVEL BOUNDARY THAT IS PROGGED TO LINGER IN KS/MO. GFS IS QUITE A
BIT COLDER THAN ECMWF/GEM AND WOULD POINT TOWARD FROZEN
PRECIPITATION /SNOW/ ON FRIDAY...BUT FOR NOW...HAVE LEANED WITH
MODEL BLENDS CLOSER TO MILDER ECMWF/GEM SOLUTIONS. PRECIPITATION
SHOULD EXIT BY FRIDAY NIGHT...LEAVING A DRY AND COOL SATURDAY.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1146 PM CDT SAT MAR 28 2015

A COLD FRONT WILL MOVE THROUGH EASTERN NEBRASKA TAF SITES BETWEEN
10Z AND 15Z. STRONG SOUTH WINDS 15 TO 30KT AND BROKEN MID LEVEL
CLOUDS WILL CONTINUE AHEAD OF THE FRONT. THEN EVEN STRONGER
NORTHWEST WINDS WILL DEVELOP BEHIND THE FRONT...INCREASING INTO THE
25 TO 40KT RANGE BETWEEN 14Z AND 18Z. CIGS NEAR FL050 ARE LIKELY
BEHIND THE FRONT...AND THERE IS A SMALL CHANCE FOR BRIEF MVFR CIGS
AND A RAIN SHOWER AS THE FRONT PASSES. CLEAR SKIES AND DIMINISHING
WINDS TO BELOW 12KT ARE EXPECTED SHORTLY AFTER 00Z.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 10 AM TO 4 PM CDT SUNDAY FOR NEZ011-012-
     015>018-030>034-042>045-050-051-065.

IA...WIND ADVISORY FROM 10 AM TO 4 PM CDT SUNDAY FOR IAZ043-055-056.

&&

$$

SHORT TERM...MAYES
LONG TERM...MAYES
AVIATION...DERGAN


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