Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 250856
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
356 AM CDT FRI APR 25 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT FRI APR 25 2014

THUNDERSTORM CHANCES SATURDAY AND SUNDAY ARE THE PRIMARY FORECAST
CONCERNS.

RELATIVELY TRANQUIL WEATHER SHOULD END THE WORK WEEK BEFORE AN UPPER
LEVEL TROUGH SWINGS TOWARD THE PLAINS SATURDAY...THEN CLOSES OFF AN
UPPER LOW ON SUNDAY...BRINGING CONTINUING CHANCES FOR THUNDERSTORMS
THEN.

FOR TODAY WE ARE STILL UNDER THE INFLUENCE OF AN UPPER WAVE MOVING
OUT OF NORTHERN MINNESOTA INTO THE GREAT LAKES. WEAK SURFACE FRONT
SWINGING THROUGH THE PLAINS WILL BRING SOUTH TO SOUTHWEST WINDS
ACROSS EASTERN NEBRASKA AND WESTERN IOWA SOUTH OF THE FRONT AS IT
SETTLES SOUTH TOWARD INTERSTATE 80. DEEP MIXING SHOULD OCCUR SOUTH
OF THE FRONT...PERHAPS TO 700MB...SUGGESTING WINDY AND WARM IN
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. HAVE TEMPERATURES CLOSE TO 80
THERE. LIGHTER WINDS FAVORING A NORTHEAST DIRECTION TO THE NORTH
WILL HOLD TEMPS TO THE MIDDLE 70S AT THE MOST. DEW POINTS WILL ALSO
DROP GIVEN DEEP MIXING...WITH AFTERNOON RELATIVE HUMIDITIES TOUCHING
20 PERCENT AT TIMES. CERTAINLY A VERY HIGH FIRE DANGER RISK IS
ADVERTISED BY METEOROLOGICAL PARAMETERS...BUT WILL NOT ISSUE RED
FLAG WARNING GIVEN RECENT RAINS AND RAPIDLY GREENING FUELS.

WE WILL START SEEING INFLUENCE OF APPROACHING UPPER TROUGH
OVERNIGHT. FRONTAL BOUNDARY WILL LOOK MORE LIKE A WARM FRONT BY
MORNING...WITH SOUTH WINDS TO THE SOUTH AND SOUTHEAST WINDS TO THE
NORTH. 50KT LOW LEVEL JET WILL BRING ELEVATED INSTABILITY TO PARTS
OF KANSAS...KEEPING ANY POTENTIAL THUNDERSTORM ACTIVITY THERE. SOUTH
TO SOUTHEAST FLOW WILL CONTINUE THROUGH THE DAY...HELPING TO
INCREASE LOW LEVEL MOISTURE PROFILE. HOWEVER MODELS SEEM OVERDONE IN
BRINGING LOWER 60S DEW POINTS INTO SOUTHEAST NEBRASKA SATURDAY
AFTERNOON. GULF DOES OPEN UP TONIGHT...BUT IT WILL TAKE A LONG TIME
FOR MOISTURE TO ADVECT FROM THE MIDDLE TEXAS COAST INTO OUR AREA.
STILL 50S DEW POINTS DO SEEM LIKELY BY LATE SATURDAY AFTERNOON OR
EARLY EVENING. FORECAST SOUNDINGS SUGGEST A STRIPE OF 1500-2000 J/KG
OF MOST UNSTABLE CAPE WILL EXTEND FROM CENTRAL KANSAS INTO SOUTHEAST
NEBRASKA BY 00Z WITH MID 50S DEW POINTS. MODERATE BULK SHEAR IS ALSO
FORECAST...0-6KM NEAR 40KT...WITH MID LEVEL LAPSE RATES NEAR 8 C/KM.
HOWEVER NOSE OF WARM AIR ALOFT WILL LIKELY CAP MOST OF THIS
POTENTIAL...SO ONLY A CHANCE FOR INITIATION. IF THINGS DO POP...LARGE
HAIL WILL BE THREAT.

LOW LEVEL JET WILL INCREASE SATURDAY NIGHT OVER FRONTAL ZONE...WITH
THETA-E ADVECTION/CONVERGENCE MAXIMIZED GENERALLY IN THE NORTHEAST
HALF OF THE CWA AFTER MIDNIGHT. ELEVATED INSTABILITY WILL REMAIN IN
THE 1500-2000 J/KG RANGE AND SHEAR NEAR 40KT. SO SEVERE THREAT WILL
CONTINUE OVERNIGHT BUT SHIFT NORTH...GENERALLY NEAR AND
NORTH/NORTHEAST OF THE OMAHA METRO AREA.

AS UPPER TROUGH CLOSES OFF IN WESTERN KANSAS/NEBRASKA ON
SUNDAY...WAVES ROTATING THROUGH THE CWA WILL KEEP AND INCREASE
THUNDERSTORM CHANCES ACROSS ALL OF OUR AREA THROUGH THE DAY. SURFACE
DEW POINTS WILL LIKELY REACH THE LOWER 60S AS TEMPERATURES ALOFT
COOL. VIGOROUS MID LEVEL FLOW WILL ALSO OVERSPREAD THE AREA. SURFACE
DRYLINE IS FORECAST TO ROTATE THROUGH KANSAS INTO SOUTHEAST NEBRASKA
IN THE AFTERNOON UNDER PARALLEL 50KT SHEAR VECTORS. WIND AND HAIL
ARE A GOOD POSSIBILITY FOR MOST OF EASTERN NEBRASKA AND SOUTHWEST
IOWA...AND WILL HAVE TO WORK OUT EXACTLY WHERE SURFACE FEATURES
WILL END UP SUNDAY AFTERNOON BEFORE OUTLINING TORNADIC RISK
AREA. BUT IF THINGS COME TOGETHER AS MODELS SUGGEST THIS
MORNING...SOUTHEAST NEBRASKA WILL BE MOST LIKELY SPOT FOR
POTENTIALLY TORNADIC STORMS.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 25 2014

UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEK AS UPPER LOW SPINS
IN THE PLAINS AND ONLY SLOW DRIFTS EAST. SEVERE THREAT WILL CONTINUE
SUNDAY EVENING BEFORE ROTATING NORTHEAST OF THE CWA AFTER MIDNIGHT.
SHOULD HAVE A LULL IN PRECIPITATION LATE SUNDAY NIGHT INTO MONDAY
MORNING BEFORE INSTABILITY SHOWERS REDEVELOP MONDAY AFTERNOON UNDER
COLD POOL ALOFT. GFS SHOWS UPPER LOW MOVING THROUGH THE CWA
TUESDAY...SO THIS MAY BRING OUR BEST CHANCE FOR WIDESPREAD SHOWERS
NEXT WEEK. OTHERWISE MORE SCATTERED ACTIVITY IS FORECAST
WEDNESDAY AND THURSDAY AS IMPULSES ROTATE AROUND LOW. COOLER
TEMPERATURES WILL RULE THE WEEK WITH HIGHS GENERALLY IN THE 50S
AFTER 60S ON MONDAY.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1125 PM CDT THU APR 24 2014

ALTHOUGH PATCHY FOG CANNOT BE RULED OUT NEAR THE MO RIVER EARLY
FRIDAY MORNING...CHANCES STILL APPEARED TOO LOW TO MENTION IN 06Z
TAFS AND THUS VFR CONDITIONS ARE EXPECTED AT TAF SITES THROUGH
26/06Z. SOME MID CLOUDS COULD MOVE ACROSS ERN NEBR LATE TONIGHT
INTO MID FRIDAY MORNING AS A WEAK LOW PRESSURE MOVES INTO ERN
NEBR. THE LOW COULD ALSO PROVIDE A PERIOD OF GUSTY SW WINDS TO
KOMA AND KLNK BY FRI AFTN...BUT THE TRACK OF THE LOW WILL CREATE A
VARIABLE AND CHANGEABLE WIND FORECAST FOR KOFK.


&&

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

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...CHERMOK



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