Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 061732
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1232 PM CDT WED MAY 6 2015

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 319 AM CDT WED MAY 6 2015

FORECAST CONCERNS WILL BE TIMING OF SHOWERS/THUNDERSTORMS AND
POTENTIAL FOR SEVERE STORMS TONIGHT AND THURSDAY.

SHORTWAVE EXTENDING FROM AN UPPER LOW/TROUGH IN NORTHEAST
COLORADO INTO CENTRAL OKLAHOMA WILL CONTINUE TO ROTATE NORTHEAST
THIS MORNING. AHEAD OF THE TROUGH...WIDESPREAD SHOWERS WERE NOTED
ACROSS EASTERN KANSAS...MOVING DIRECTLY TOWARD SOUTHEAST NEBRASKA.
SEE NO REASON THIS TREND WILL NOT CONTINUE THIS MORNING...SO
EXPECT RAIN TO BECOME WIDESPREAD ACROSS EASTERN NEBRASKA AND
SOUTHWEST IOWA EARLY IN THE DAY. THUNDER HAS BEEN ALMOST NON-
EXISTENT WITHIN THE LARGER AREA OF SHOWERS GIVEN WEAK INSTABILITY
AND SHEAR. EXTRAPOLATION OF RAIN AREA AND MOST MODEL OUTPUT
SUGGEST SHOWERS WILL BE LIFTING NORTHEAST OF OUR AREA BY EARLY
AFTERNOON...WITH MORE ISOLATED SHOWERS TO FOLLOW. BY MID TO LATE
AFTERNOON...ANOTHER SHORTWAVE IS FORECAST TO EMERGE FROM THE HIGH
PLAINS AND ENTER CENTRAL NEBRASKA. INSTABILITY AXIS SHOULD REMAIN
TO OUR WEST AT THAT TIME...WITH STORMS DEVELOPING ALONG DRYLINE
FROM SOUTHWEST NEBRASKA INTO CENTRAL KANSAS. THUS WILL MAINTAIN
RELATIVELY LOW RAIN CHANCES THROUGH LATE AFTERNOON AS WE WAIT FOR
THOSE STORMS TO PROGRESS EAST OVERNIGHT.

TONIGHT...THUNDERSTORMS SHOULD INCREASE IN COVERAGE IN NORTHEAST
NEBRASKA CLOSER TO THE NEGATIVELY TILTED TROF. DAYTIME INSTABILITY
IS MODERATE ACROSS CENTRAL KANSAS...1000-3000J/KG. THE LOW LEVEL
AND H85 FLOW BACKS AND TENDS TO FOCUS THE STRONGER STORMS TO THE
WEST OF THE FORECAST AREA FROM SOUTH CENTRAL NEBRASKA AND IN
KANSAS. THE INSTABILITY AXIS EXTENDS FROM OKLAHOMA ACROSS KANSAS
INTO THE FORECAST AREA THIS EVENING AND OVERNIGHT. AS THE NIGHT
PROGRESSES THE STEERING FLOW INCREASES THE THUNDERSTORM COVERAGE
ACROSS THE COUNTY FORECAST AREA. CAPE OF 500TO 1500J/KG DOES PUSH
INTO THE FORECAST AREA. STRONGER DEEP LAYER SHEAR AT 00Z IS
GENERALLY FROM CENTRAL KANSAS INTO SOUTHERN NEBRASKA AT 35-40KTS
AND AROUND 25KTS OVERNIGHT. THE ORGANIZED SEVERE WEATHER SHOULD BE
WEST OF THE FORECAST AREA...HOWEVER SOME STRONG TO SEVERE STORMS
COULD WORK EAST OVERNIGHT. PWATS ARE AROUND 1.5 INCHES BY 06Z AND
DID INCLUDE SOME HIGHER QPF AMOUNTS. AMOUNTS COULD VARY FROM 0.25
TO 2 INCHES. WILL MENTION THIS IN THE HWO TOO.

RIPPLES IN THE SOUTHWEST FLOW ALOFT CONTINUE FOR THURSDAY WITH THE
COLD FRONT PUSHING ACROSS THE FORECAST AREA. THE MOISTURE IS NOT
QUITE AS FAVORABLE...HOWEVER THERE IS MODERATE INSTABILITY AND
SLIGHTLY BETTER SHEAR PRESENT. THUNDERSTORMS APPEAR LIKELY ALONG
THE FRONT...DEVELOPING IN THE AFTERNOON AND CONTINUING OVERNIGHT.
SEVERE STORMS MAY DEVELOP IF INSTABILITY IS REALIZED.  WITH THE
FRONT TO THE SOUTH OF THE FORECAST AREA FRIDAY...SHOULD SEE MAINLY
DRY CONDITIONS NORTH...ISOLATED CENTRAL AND CHANCE POPS NEAR THE
KANSAS BORDER.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 319 AM CDT WED MAY 6 2015

SATURDAY...CLOSED H5 LOW PRES NEAR THE FOUR CORNER AREA WITH
NORTHEAST SURFACE FLOW ACROSS THE FORECAST AREA. DRIER FLOW SHOULD
LIMIT SHOWERS AND THUNDERSTORMS...HOWEVER THE SURFACE FRONT IS
JUST TO THE SOUTH IN KANSAS...SO COULD BE SOME ACTIVITY NEAR THE
NEBRASKA SOUTH DAKOTA BORDER. SATURDAY NIGHT THROUGH MONDAY...THE
MID TROPOSPHERIC LOW WILL EJECT INTO THE PLAINS. THE TRACK STILL
HAS A WIDE RANGE OF SOLUTIONS...AND THIS WILL IMPACT TO LOCATION
OF THE HEAVIER RAIN AND POTENTIAL FOR SEVERE STORMS. HIGH POPS
SATURDAY NIGHT WITH THE SYNOPTIC LIFT AND STRONG WARM AIR
ADVECTION REGIME. THE TRACK OF THE SURFACE LOW VARIES NORTHERN
KANSAS TO NORTHERN NEBRASKA SUNDAY INTO SUNDAY NIGHT. THESE
DETAILS SHOULD BECOME CLEARER AS WE APPROACH THE WEEKEND. SOME
TROF ENERGY COULD LINGER INTO MONDAY...OTHERWISE DRY TUESDAY.
HIGHS IN THE 60S AND 70S.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1227 PM CDT WED MAY 6 2015

VARIABLE CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH
OCCASIONAL THUNDERSTORMS. THUNDERSTORMS APPEAR MORE LIKELY
AFTER 00Z WITH POTENTIAL FOR SEVERE STORMS THROUGH 06Z THEN
HEAVY RAIN 06Z-12Z. STRONG SOUTHERLY FLOW EXPECTED THROUGH
12Z.

&&

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

$$

SHORT TERM...DERGAN/ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...FOBERT


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