Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 281745
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1245 PM CDT THU MAY 28 2015

.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 303 AM CDT THU MAY 28 2015

SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES WEAK WEST-
SOUTHWESTERLY UPPER- LEVEL FLOW ACROSS THE CENTRAL US...WITH A FEW
RIPPLES...AND WITH AN UPPER- LEVEL TROUGH NOTED IN ID/MT EXTENDING
INTO THE DESERT SOUTHWEST. NO NOTABLE 500MB HEIGHT FALLS WERE
ANALYZED IN THE CONUS..THOUGH BROAD HEIGHT RISES UP TO 100M WERE
NOTED FROM THE MO RIVER VALLEY TOWARD THE GREAT LAKES. AN AXIS OF
850MB 8C+ DEWPOINTS EXTENDED NORTHWARD THROUGH THE HIGH
PLAINS...WITH A DRY POCKET UNDER MID- LEVEL RIDGING FROM EASTERN
NEB/EASTERN DAKOTAS INTO IA/WESTERN GREAT LAKES. HINTS OF AN EML
ALSO MADE AN APPEARANCE...WITH 10C+ TEMPERATURES AT 700MB IN
NM/SOUTHERN TX. SURFACE TROUGH AXIS AT 07Z EXTENDED ALONG THE HIGH
PLAINS.

MAIN FORECAST CONCERNS ARE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
TODAY THROUGH FRIDAY NIGHT.  AREAS OF CONVECTION HAVE BEEN REMAINED
SCATTERED...WITH NONE IMMINENTLY THREATENING THE CWA.  SHORT-RANGE
MODELS CONTINUE TO INDICATE SHOWERS AND THUNDERSTORMS MOVING INTO AT
LEAST THE SOUTHERN CWA YET THIS MORNING...AND HAVE KEPT A CHANCE IN
THE SOUTHWEST TO WESTERN CWA...THOUGH CONFIDENCE IS LOW.
INSTABILITY IS WEAK IN EASTERN NEB...AND THINK STORMS WOULD BE
WEAKENING.  WITH THOUGHT THAT PRECIPITATION COVERAGE MIGHT BE LOWER
THAN PROGS...HAVE INDICATED TEMPERATURES ON THE WARMER SIDE OF
GUIDANCE TODAY.  DO THINK SHOWERS/THUNDERSTORMS WILL DEVELOP IN THE
CWA THIS AFTERNOON/EVENING AS SHORTWAVE KICKS ACROSS THE
REGION...THOUGH STILL THINK BETTER INSTABILITY WILL BE WEST AND
SEVERE WEATHER POTENTIAL WILL BE LIMITED.  CONVECTION SHOULD
CONTINUE TONIGHT AT LEAST IN SOME SENSE...PERHAPS IN BROKEN AREAS AS
IS ONGOING THIS MORNING...AND CURRENT POPS MIGHT BE A BIT ON THE
AGGRESSIVE SIDE.

CONVECTIVE EVOLUTION BECOMES EVEN MORE UNCERTAIN ON FRIDAY.
UPPER=LEVEL TROUGH WILL EJECT ACROSS THE PLAINS ON FRIDAY...WITH
SURFACE COLD FRONT PUSHING OUT OF SD FRIDAY AFTERNOON/EVENING.  MAY
BE SOME ONGOING SHOWERS/THUNDERSTORMS IN THE MORNING OR THROUGH THE
DAY...WITH LITTLE TO HOLD IT BACK...AND THAT ACTIVITY WOULD WEAKEN
INSTABILITY.  FRONTAL PASSAGE WILL BRING HIGHER CHANCES FOR SHOWERS
AND THUNDERSTORMS FRIDAY AFTERNOON/EVENING...WITH MUCH MORE COOL AND
STABLE AIRMASS BEHIND THE FRONT. HAVE SPED TIMING OF FRONTAL PASSAGE
JUST A BIT MORE...BUT DID HOLD ONTO SLIGHT CHANCES OF SHOWERS
THROUGH 12Z SATURDAY IN THE SOUTHERN CWA BEHIND THE FRONT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 303 AM CDT THU MAY 28 2015

BEHIND THE FRONT...COOLER AND DRIER WEATHER WILL SPILL INTO THE
CENTRAL PLAINS FOR THE WEEKEND.  UPPER-LEVEL RIDGE WILL BUILD
EASTWARD INTO THE CENTRAL US INTO EARLY NEXT WEEK...KEEPING
WEATHER DRY AND BRINGING MODERATING TEMPERATURES AS LOW- TO MID-
LEVEL FLOW RETURNS TO SOUTHERLY. GFS AND ECMWF BOTH HOLD AN UPPER-
LEVEL TROUGH/WEAK UPPER LOW IN THE SOUTHERN/SOUTHEASTERN US INTO
EARLY NEXT WEEK. MOISTURE FROM THE GULF MAY DIVERT TOWARD THAT
FEATURE...WITH SOME RETURN FLOW MOISTURE ADVECTED INTO THE HIGH
PLAINS...AND DRIER AREA BETWEEN FOR MUCH OF THE CENTRAL PLAINS.

RIDGE BREAKS DOWN TO SOUTHWESTERLY FLOW AROUND WEDNESDAY AS UPPER-
LEVEL TROUGH DIGS INTO THE WESTERN US...WITH CUTOFF UPPER LOW
HOLDING ITS PLACE.  FIRST EJECTING SHORTWAVE MAY BRING ACTIVE
WEATHER TO THE NORTHERN PLAINS ON TUESDAY NIGHT/WEDNESDAY...BUT THAT
BATCH LOOKS TO STAY NORTH OF THE CWA.  NEXT WAVE AROUND WEDNESDAY
NIGHT/THURSDAY LOOKS MORE LIKELY TO BRING ACTIVE WEATHER TO THE AREA.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1227 PM CDT THU MAY 28 2015

AVIATION FORECAST REMAINS DIFFICULT WITH SPOTTY CONVECTION IN THE
FORECAST THROUGH THE PERIOD. SURFACE LOW CENTERED OVER EAST
COLORADO AS OF 17Z WAS PUMPING MOISTURE FROM THE SOUTH INTO EAST
NEBRASKA AND WESTERN IOWA. HAVE ADDED VCSH TO KLNK AND KOMA AND
NOT INCLUDED THUNDER AT THIS TIME. VFR TO MVFR EXPECTED AT ALL
THREE TAF SITES FOR THE MOST PART THROUGH THIS FORECAST PERIOD.
THOUGH A STRAY THUNDERSTORM MAY HAVE TO BE DEALT WITH...HAVE NOT
ATTEMPTED TO BRING ORGANIZED THUNDERSTORMS INTO THE FORECAST UNTIL
AROUND 12Z...ESPECIALLY AT KOMA AND KLNK...WHEN ACTUAL COLD FRONT
WILL BE APPROACHING FROM THE WEST. EXPECT SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT TO MOVE ACROSS TAF
SITES BETWEEN 15Z AND 18Z.

&&

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

$$

SHORT TERM...MAYES
LONG TERM...MAYES
AVIATION...MEYER



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