Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 012251
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
551 PM CDT FRI MAY 1 2015

.SHORT TERM...(TONIGHT)
ISSUED AT 305 PM CDT FRI MAY 1 2015

WEAK FRONTAL BOUNDARY SLIPPED INTO NORTHEAST NEBRASKA AND NORTHWEST
IOWA EARLIER THIS MORNING...AND HAS SINCE STALLED NEAR A WAYNE TO
NELIGH LINE. NO REAL PUSH BEHIND THIS BOUNDARY...SO NOT EXPECTING IT
TO DRIFT MUCH FROM WHERE IT IS BEFORE WASHING OUT LATER TONIGHT.
PERSISTENT SHOWERS IN NORTHEAST NEBRASKA INTO WEST CENTRAL IOWA HAVE
BEEN SLOWLY DECREASING IN INTENSITY TODAY...AND EXPECT THIS TREND TO
CONTINUE AS UPPER SUPPORT MOVES OFF TO THE EAST. OTHER ISOLATED
SHOWERS IN SOUTHEAST NEBRASKA WILL FOLLOW A SIMILAR TREND OF SLOWLY
DISSIPATING THROUGH THE EVENING. OTHER SHOWERS BETWEEN THESE TWO
AREAS ARE POSSIBLE...BUT WILL BE SPOTTY AT BEST. THEN LATER
TONIGHT...SHORT RANGE MESOSCALE MODELS INCLUDING RAP/ARW/NMM ALONG
WITH NAM AND GFS INDICATE INCREASING LOW LEVEL JET NEAR 30KT
POINTING INITIALLY INTO SOUTH CENTRAL NEBRASKA BY MIDNIGHT THEN TO
THE EAST AFTER MIDNIGHT. SCATTERED SHOWERS ARE INDICATED ON NOSE OF
THAT JET WHERE THETA-E ADVECTION IS MAXIMIZED. AREAS GENERALLY ALONG
AND SOUTH OF INTERSTATE 80...AND PERHAPS A COUNTY OR TWO TO THE
NORTH...COULD SEE MORE SHOWERS BETWEEN MIDNIGHT AND SUNRISE.
INSTABILITY IS RATHER WEAK...BUT ENOUGH TO POTENTIALLY SPARK A
RUMBLE OF THUNDER OR TWO.

.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 305 PM CDT FRI MAY 1 2015

LOWERING CONDENSATION PRESSURE DEFICITS AND STRONG ISENTROPIC LIFT
AROUND THE 305K SFC SHOULD ALLOW SCATTERED SHOWERS TO CONTINUE
ACROSS PORTIONS OF SOUTHEAST NEBRASKA AND SOUTHWEST IOWA SATURDAY
MORNING.  IN ADDITION...THE RIGHT REAR QUAD OF A WEAK 300MB JET
SEGMENT WILL BE PASSING OVERHEAD TO PROVIDE LARGE SCALE VERTICAL
MOTION FOR ASCENT. WILL BOOST THE POPS MAINLY ALONG AND SOUTH OF
INTERSTATE 80 TO THE 30 PERCENT RANGE. THE PCPN SHOULD END FROM WEST
TO EAST BY EARLY AFTERNOON.

STRONG LOW LEVEL WARM AIR ADVECTION WILL BE UNDERWAY SATURDAY
NIGHT INTO SUNDAY MORNING WITH A SOUTHWESTERLY 35-40KT 850MB JET.
A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS OUR FAR
SOUTHEASTERN CWA SUNDAY MORNING BUT A MAJORITY OF THE AREA SHOULD
REMAIN DRY.

THETA-E RIDGE AXIS WILL MOVE OVER THE AREA SUNDAY
AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. A MODERATELY
UNSTABLE AIRMASS WILL BE IN PLACE AHEAD OF THE FRONT WITH MUCAPE
ON THE ORDER OF 1500-2500 J/KG. 0-6KM BULK SHEAR LOOKS FAIRLY
WEAK BUT WE SHOULD BE ABLE TO INITIATE THUNDERSTORMS ALONG THE
SURFACE CONVERGENCE NEAR THE FRONTAL BOUNDARY. THE FRONT WILL
CONTINUE TO SLIDE SOUTHEAST THROUGH THE EVENING HOURS...AND STALL
ACROSS NORTHERN KANSAS. CONTINUED SHOWERS AND THUNDERSTORMS ARE
LIKELY ALONG THIS BOUNDARY IN KS AND WILL POSSIBLY DRIFT NORTH
ALONG THE 850MB BOUNDARY THROUGH MONDAY. BY MONDAY NIGHT...THE
FRONT PUSHES NORTH WHICH WILL ALLOW CONTINUED TSTM CHANCES OVER
THE FORECAST AREA.

A SHORTWAVE TROUGH WILL BE MOVING NORTHEAST ACROSS NEW
MEXICO/SOUTHEASTERN COLORADO WHILE BECOMING NEGATIVELY TILTED.
STRONG LOW LEVEL FLOW FROM THE THE OPEN GULF WILL BRING SFC
DEWPOINTS IN THE UPPER 50S/LOWER 60S TO THE REGION. ON AND OFF
SHOWERS AND THUNDERSTORMS ARE LIKELY THROUGH NEXT WEEK AS THIS UPPER
TROUGH KICKS THROUGH THE REGION. HIGHS WILL RANGE IN THE 70S THROUGH
MUCH OF THE WEEK.

&&

.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 544 PM CDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A MIX OF SCT-BKN
MID LEVEL CLOUDS WILL CONTINUE THROUGH SATURDAY BUT WILL LIKELY
REMAIN ABOVE FLO050. AS MOISTURE INCREASES LATE TONIGHT AND INTO
THE DAY ON SAT THERE IS SOME CHC OF ISO/SCT SHRA...ESPECIALLY AT
KLNK BUT CONFIDENCE IS NOT GREAT ENOUGH TO INCLUDE A MENTION AT
THE MOMENT.

&&

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

&&

$$

SHORT TERM...DERGAN
LONG TERM...KERN
AVIATION...



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