Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 282336
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
636 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...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 635 PM CDT SAT MAR 28 2015

VFR CONDITIONS ARE FORECAST THROUGH SATURDAY AFTERNOON...HOWEVER
VERY STRONG WINDS ARE EXPECTED LATE SUNDAY MORNING INTO THE
AFTERNOON. A COLD FRONT WILL SWING THROUGH EASTERN NEBRASKA
OVERNIGHT. AHEAD OF IT...SOUTH WINDS INCREASING INTO THE 20 TO 30KT
RANGE ARE EXPECTED AT ALL TAF SITES. FRONT SHOULD MOVE THROUGH KOFK
NEAR 10Z AND KOMA/KLNK AREAS NEAR 12Z. THERE IS A SMALL CHANCE RAIN
SHOWERS WILL ACCOMPANY THE FRONT...AND COULD BRING BRIEF MVFR
CIGS/VSBYS. HOWEVER MOST ACTIVITY IS FORECAST EAST OF THE AREA.
WINDS WILL TURN TO THE NORTHWEST AFTER FRONTAL PASSAGE AND INCREASE
INTO THE 30 TO 40KT RANGE BETWEEN 15Z AND 18Z...THE BEGIN TO
DECREASE AFTER 21Z SUNDAY AFTERNOON.

&&

.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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