Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 261727
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1227 PM CDT FRI JUN 26 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT FRI JUN 26 2015

THE CHANCE FOR THUNDERSTORMS TODAY IS THE PRIMARY FORECAST CONCERN.
THEN A GENERALLY DRY AND WARMER WEEKEND...WITH THE EXCEPTION OF A
SMALL CHANCE FOR STORMS SUNDAY.

NORTHWEST MID LEVEL FLOW ACROSS THE PLAINS WAS NOTED ON EVENING
UPPER AIR CHARTS AND SHORT TERM MODEL OUTPUT. A COUPLE OF SHORTWAVES
COULD BE IDENTIFIED WITHIN THE FLOW...AND RECENT RAP HEIGHT
FORECASTS ALONG WITH WATER VAPOR IMAGERY SUGGESTED ONE WAVE WAS
MOVING OUT OF SOUTHEAST NEBRASKA AS OF 3 AM...AND ANOTHER WAS
APPROACHING NORTHEAST NEBRASKA FROM SOUTH DAKOTA. BOTH WAVES WERE
TRIGGERING SCATTERED SHOWERS AND STORMS...HOWEVER THE STRONGEST WERE
IN NORTHERN KANSAS WHERE LIFT WAS MAXIMIZED JUST NORTH OF FRONTAL
BOUNDARY EXTENDING FROM KANSAS CITY TO WICHITA.

GIVEN NORTHWEST FLOW ALOFT...SOUTHERN STORMS MOVING OUT OF OUR AREA
WILL REMAIN THERE THIS MORNING. SHORTWAVE TO THE NORTH WILL
GRADUALLY WORK SOUTHEAST TODAY...BUT ABSENCE OF SURFACE BOUNDARY/LOW
LEVEL CONVERGENCE SUGGESTS ACTIVITY WILL REMAIN ISOLATED TO
SCATTERED IN NATURE. IN FACT...MANY SHORT RANGE MESOSCALE MODELS
INCLUDING HRRR AND RAP SUGGEST A DECREASE IN ACTIVITY THROUGH THE
MORNING BEFORE AFTERNOON HEATING HELPS BUBBLE UP WIDELY SCATTERED
AFTERNOON CONVECTION. SO WILL PLAY THE HIGHEST POPS IN NORTHEAST
NEBRASKA THIS MORNING...THEN BROADBRUSH SMALL CHANCES THROUGH THE
AFTERNOON ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA. COULD
SEE SOME LINGERING SHOWERS/STORMS IN SOUTHEAST NEBRASKA OR SOUTHWEST
IOWA DURING THE EARLY EVENING BEFORE SHORTWAVE PUSHES FARTHER AWAY
AND WE LOSE AFTERNOON HEATING.

OTHERWISE WE WILL SEE A TENDENCY TOWARD NORTHERLY LOW LEVEL FLOW
TONIGHT AND SATURDAY AS HIGH PRESSURE SETTLES ACROSS THE
REGION...AND BRINGS SLIGHTLY DRIER AIR INTO OUR AREA. SHOULD SEE
PLENTY OF SUNSHINE SATURDAY WITH HIGHS IN THE LOWER 80S AFTER
MORNING LOWS IN THE LOWER 60S.

SOUTHERLY FLOW WILL RETURN SATURDAY NIGHT AS A SHORTWAVE DIVES INTO
MINNESOTA THEN EVENTUALLY IOWA/WISCONSIN/ILLINOIS. SURFACE COLD
FRONT WILL FOLLOW THIS WAVE AND SWEEP THROUGH EASTERN NEBRASKA AND
SOUTHWEST IOWA ON SUNDAY. CONVECTION SATURDAY NIGHT SHOULD BE
CONFINED TO AREAS TO OUR NORTHEAST WHERE STRONG WARM ADVECTION IS
REALIZED JUST AHEAD OF MID LEVEL WAVE. ON SUNDAY...AXIS OF BEST LIFT
NEAR SHORTWAVE AND SURFACE REFLECTION WILL STILL LIE WELL TO OUR
EAST AND NORTHEAST IN MINNESOTA AND IOWA...BUT COULD SEE A FEW
SHOWERS OR STORMS NEAR AND EAST OF THE NEBRASKA/IOWA BORDER AS COLD
FRONT SWINGS SOUTHEAST. SHOULD SEE NICE WARMING ON SUNDAY AS
SOUTHWEST FLOW AHEAD AND NORTHWEST FLOW BEHIND FRONT WILL PROMOTE
DECENT MIXING. HIGHS THEN SHOULD EASILY REACH THE MID AND UPPER
80S.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 333 AM CDT FRI JUN 26 2015

GENERAL MID LEVEL FLOW PATTERN CHANGES ONLY A LITTLE DURING THE
WEEK. BROAD HIGH PRESSURE WILL REMAIN OVER THE SOUTHWESTERN STATES
THROUGH THE PERIOD. MEANWHILE UPPER LOW IN THE EASTERN GREAT LAKES
EARLY IN THE PERIOD WILL LIFT TO THE NORTHEAST...LEAVING BROAD
TROUGH BEHIND OVER THE EASTERN HALF OF THE COUNTRY. IN BETWEEN THESE
FEATURES...FLOW IN THE CENTRAL PLAINS WILL SHIFT FROM NEARLY
NORTHERLY TO NORTHWESTERLY BY MID WEEK. SEVERAL IMPULSES RIDING OVER
WESTERN RIDGE WILL ENTER THE PLAINS...BRINGING OFF AND ON
THUNDERSTORM CHANCES TO OUR REGION. GFS AND ECMWF ARE IN FAIRLY GOOD
AGREEMENT WITH THIS OVERALL PATTERN CHANGE...BUT DIFFER ON TIMING OF
PRECIPITATION-PRODUCING SHORTWAVES.

HOWEVER BOTH MODELS ARE RELATIVELY SIMILAR IN DROPPING A MORE
SIGNIFICANT SHORTWAVE INTO THE PLAINS ON TUESDAY...INCREASING
THUNDERSTORM CHANCES IN EASTERN NEBRASKA AND WESTERN IOWA TUESDAY
NIGHT AS ATTENDANT SURFACE LOW AND FRONTAL SYSTEM MOVE THROUGH THE
REGION. WILL HAVE THE HIGHEST PRECIP CHANCES AT THIS TIME...THOUGH
STILL ONLY IN THE CHANCE CATEGORY AS MOISTURE RETURN AFTER SUNDAY
COLD FRONT WILL BE SLOW TO OCCUR. SHOULD SEE MINIMAL RAIN CHANCES
BEHIND THIS SYSTEM ON WEDNESDAY AND THURSDAY...BUT GIVEN UNCERTAINTY
IN SMALL-SCALE MID LEVEL FEATURES...CAN NOT RULE OUT A STRAY STORM
OR TWO. OTHERWISE EXPECT TEMPERATURES TO AVERAGE 60S AND 80S FOR
LOWS AND HIGHS THROUGH THE PERIOD.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1226 PM CDT FRI JUN 26 2015

VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES.  A FEW
SHOWERS AND THUNDERSTORMS COULD POP UP THIS AFTERNOON WITH DAYTIME
HEATING...HOWEVER CONFIDENCE IN COVERAGE STILL REMAINS FAIRLY LOW.
NORTHERLY WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT WITH SKIES
CLEARING THROUGH SATURDAY MORNING.

&&

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

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...KG



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