Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 291826
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
126 PM CDT FRI APR 29 2016

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 307 AM CDT FRI APR 29 2016

INCREASING CHANCES FOR RAIN...SOME POTENTIALLY HEAVY...THROUGH THE
WEEKEND IS THE PRIMARY FORECAST CONCERN.

UPPER TROUGH DRIFTING THROUGH THE FOUR CORNERS REGION THIS MORNING
WILL BE THE MAIN DRIVING FORCE FOR RAINFALL THIS WEEKEND. THAT
TROUGH IS FORECAST TO DEEPEN INTO A LOW CENTER IN COLORADO LATER
TODAY...THEN GRADUALLY DRIFT INTO NORTH CENTRAL KANSAS OR SOUTH
CENTRAL NEBRASKA BY SATURDAY AFTERNOON...BEFORE WEAKENING AS IT
PROGRESSES EAST OF THE MISSISSIPPI RIVER BY SUNDAY AFTERNOON. DEEP
LAYER MOIST ADVECTION FROM THE GULF WILL CONTINUE INTO THE PLAINS
AHEAD OF APPROACHING TROUGH/LOW THROUGH SATURDAY NIGHT. LOW LEVEL
MOISTURE BELOW 850MB WILL INTERACT WITH FRONTAL BOUNDARY ALONG
KANSAS AND OKLAHOMA BORDER AREA INITIALLY...THEN SPREAD TOWARD OUR
AREA AS THAT BOUNDARY IS KICKED NORTHWARD. SO INITIALLY ONLY MID
LEVEL MOISTURE WILL BE AVAILABLE FOR RAIN HERE. AND PERSISTENT
EAST TO NORTHEAST LOW LEVEL WINDS WILL TEND TO LIMIT NORTHWARD
EXTENT OF PRECIPITATION TODAY...SO HAVE SLOWED DOWN RAIN CHANCES
OVERSPREADING EASTERN NEBRASKA...ESPECIALLY DURING THE DAYLIGHT
HOURS.

BY TONIGHT...850 FLOW SHOULD BE APPROACHING THE SOUTHERN NEBRASKA
BORDER WITH IMPLIED ISENTROPIC UPGLIDE OVERSPREADING ALL OF EASTERN
NEBRASKA AND SOUTHWEST IOWA. LAYER MOISTURE INCREASES MARKEDLY AS
WELL...WITH PRECIPITABLE WATER VALUES INCREASING FROM NEAR 0.6 TO
OVER AN INCH FROM THIS AFTERNOON THROUGH SATURDAY MORNING.

EXPECT AN AREA OF RAIN TO BECOME WIDESPREAD FROM NORTH CENTRAL TO
SOUTHEAST NEBRASKA THIS EVENING...AND SPREADING NORTHEAST WITH TIME
OVERNIGHT. WILL CARRY FAIRLY HIGH POPS FOR THIS OCCURRENCE...AND
GIVEN PRECIPITABLE WATER VALUES AND GENERALLY SLOW MOVEMENT...COULD
SEE RAINFALL EXCEEDING AN INCH IN SOME AREAS BEFORE SUNRISE. BEST
AREA OF THETA-E CONVERGENCE WILL STALL OVER NORTHEAST NEBRASKA
SATURDAY MORNING WHERE HIGH CHANCES AND POTENTIALLY HEAVY RAINS WILL
CONTINUE. TO THE SOUTH...DRY AIR WILL DECREASE PRECIPITATION CHANCES
EARLY IN THE DAY ACROSS SOUTHEAST NEBRASKA...BUT INCREASING
INSTABILITY WHERE COLD MID LEVEL TEMPS OVERSPREAD THE AREA WILL LEAD
TO AT LEAST SCATTERED AFTERNOON SHOWERS OR THUNDERSTORMS.

AS UPPER LOW BEGINS TO FILL AND MOVE EAST SATURDAY NIGHT...WILL SEE
MARKEDLY DECREASING RAIN CHANCES AFTER MIDNIGHT WITH A CONTINUED
DOWNWARD TREND THROUGH SUNDAY.

OTHERWISE MAINLY A CLOUDY FORECAST THROUGH MUCH OF THE
WEEKEND...LEADING TO SMALLER THAN NORMAL DIURNAL TEMPERATURE
CHANGES. WE SHOULD SEE LOWS IN THE 40S AND HIGHS IN THE UPPER 40S
TO MID 50S FRIDAY AND SATURDAY...WITH A LITTLE MORE POTENTIAL FOR
AFTERNOON SUNSHINE ON SUNDAY PUSHING HIGHS CLOSER TO 60.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 307 AM CDT FRI APR 29 2016

THE LONGER TERM FORECAST WILL REFLECT MAINLY DRY AND WARMER WEATHER
THROUGH NEXT WEEK. THERE IS DECENT AGREEMENT BETWEEN MEDIUM RANGE
MODELS IN EVENTUALLY DEVELOPING AN OMEGA BLOCK PATTERN ACROSS THE
CONUS BY THURSDAY WITH UPPER TROUGHS/LOWS OFF THE WEST COAST AND
FROM THE GREAT LAKES INTO THE SOUTHEASTERN U.S...AND A RIDGE FROM
NORTHERN MEXICO INTO THE NORTHERN ROCKIES. BEFORE THAT PATTERN
DEVELOPS...THERE ARE A FEW DISCREPANCIES WITH MID LEVEL WAVES MOVING
ACROSS THE PLAINS THAT COULD BRING US A SLIGHT CHANCE FOR SHOWERS AT
LEAST EARLY IN THE WEEK. THE ECMWF IS MOST BULLISH IN POPPING A FEW
AFTERNOON SHOWERS MONDAY THROUGH WEDNESDAY...WITH THE GFS GENERALLY
DRY. GIVEN LACK OF CONSENSUS BETWEEN MODELS AND SPORADIC NATURE OF
POTENTIAL PRECIPITATION...DO NOT HAVE ENOUGH CONFIDENCE TO INTRODUCE
RAIN CHANCES AT ANY POINT NEXT WEEK. OTHERWISE HIGH TEMPERATURES ARE
FORECAST IN THE LOWER 60S BEGINNING THE WEEK WITH A FEW DEGREES OF
WARMING EACH DAY TO THE 70S BY THURSDAY.

&&

.AVIATION...(18Z TAFS FOR KOMA...KLNK...KOFK THROUGH 18Z SATURDAY)
ISSUED AT 1250 PM CDT FRI APR 29 2016

LOOK FOR DETETIORATING CONDITIONS AT ALL SITES ESPECIALLY AFTER
00Z. MVFR CIGS WILL CONTINUE WITH SHOWERS AND ISOLATED
THUNDERSTORMS OVERSPREADING THE AREA. THE AFTERNOON WILL BE MAINLY
DRY WITH SOME SPRINKLES OR LIGHT SHOWERS LIFTING NORTH/DEVELOPING
FROM KANSAS IN THE EARLY EVENING. THE SHOWERS WILL PICK UP THIS
EVENING AND CONTINUE OVERNIGHT WITH MVFR VSBYS AND SOME PATCHY IFR
CIGS/VSBYS. INSTABILITY WILL INCREASE TOWARD 12Z...AND WILL NEED
TO ASSESS THUNDER POTENTIAL AT KLNK AND KOMA. NORTHEAST SURFACE
WINDS WILL INCREASE FROM 10KTS TO 20KTS AND GUSTY AS THE EVENING
PROGRESSES. LOW LEVEL WIND SHEAR WILL ALSO INCREASE FROM THE EAST
AT KLNK AND KOMA AT 35 TO 45KTS.

&&

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

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...ZAPOTOCNY



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