Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 041733
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1233 PM CDT MON MAY 4 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM CDT MON MAY 4 2015

THE PRIMARY FORECAST CONCERNS TODAY ARE COVERAGE AND INTENSITY OF
THE CONVECTION EXPECTED TO DEVELOP.

LARGE SCALE PATTERN FEATURES A CYCLONICALLY CURVED JET MAX IN THE
POLAR JET ALONG THE CANADIAN BORDER NORTHEAST INTO ONTARIO...AND
AN ANTICYCLONICALLY CURVED MAX IN THE SUBTROPICAL JET OVER MEXICO.
MID TROPOSPHERIC WINDS WERE FAIRLY WEAK AT OUR LATITUDE BUT SHEAR
THE PAST FEW EVENINGS HAS BEEN STRONG ENOUGH FOR ORGANIZED STORMS.
SFC ANALYSIS AT 08Z SHOWED A COLD FRONT STRETCHING FROM WI ACROSS
PARTS OF IA...SERN NE...KS AND THEN BACK INTO SERN CO. COOL HIGH
PRES HAD BUILT INTO ND. DEWPOINTS HAD DROPPED INTO THE 20S AND
30S ACROSS SD BUT RANGED TO THE 50S SOUTH OF THE FRONT. A FEW
STORMS WERE STILL ONGOING NEAR THE NE/MO/KS BORDER AREA AND OVER
SCNTRL NE AS OF 08Z AND SPOTTY ELEVATED SHRA OR WEAK TSRA WERE
NOTED FROM PARTS OF NERN NE INTO NWRN IA.

AVAILABLE HRRR/RAP/HIGH RES ARW MODELS ARE IN DECENT AGREEMENT FOR
TODAY THAT STORM COVERAGE WILL BE ON THE INCREASE THIS MORNING AS
LIFT INCREASES NORTH OF THE STALLED BOUNDARY. THEN THIS AFTERNOON
PRECIPITATION SHOULD BECOME FAIRLY WIDESPREAD. ALTHOUGH HIGHS ARE
EXPECTED TO BE MOSTLY IN THE MID 60S TO LOWER 70S AT MOST SPOTS...
PARTS OF SERN NE AND FAR SWRN IA MAY REACH WELL INTO THE 70S.  SPC
DAY 1 OUTLOOK SEEMS REASONABLE WITH OUR SRN COUNTIES IN THE SLGT
RISK AREA. MAIN THREATS WOULD BE HAIL AND DAMAGING WINDS. FOR NOW
TORNADO POTENTIAL SEEMS FAIRLY LOW AND WILL NOT MENTION IN THE
HAZARDOUS WEATHER OUTLOOK. IF THAT FRONTAL BOUNDARY CAN LIFT UP
INTO SERN NE...CHANCES WOULD INCREASE.

FAIRLY WIDESPREAD STORMS THIS EVENING SHOULD MOVE EAST/NORTHEAST AND
DECREASE IN COVERAGE FOR THE OVERNIGHT HOURS. INCREASING SOUTHERLY
FLOW...ESPECIALLY JUST ABOVE THE SURFACE...MAY HELP LIFT THE FRONTAL
BOUNDARY NORTH LATE TONIGHT BUT MORESO ON TUESDAY. THIS MAY ALSO
HELP TO DESTABILIZE THE ATMOSPHERE DURING THE DAY WITH PCPN CHANCES
INCREASING TUESDAY. BUT THE FOCUS FOR STORM ACTIVITY SHOULD BE
STRONGEST IN TWO AREAS ON TUESDAY...TO OUR WEST AND TO OUR
NORTHEAST. STORM CHANCES SHOULD BE ON THE INCREASE AGAIN BY LATE
TUESDAY NIGHT AS ENERGY ALOFT MOVES NORTHEAST ACROSS THE REGION.
INCREASED POPS INTO THE LIKELY CATEGORY AGAIN BY LATE TUESDAY
NIGHT AND CONTINUED THOSE ON WEDNESDAY. TEMPERATURES WEDNESDAY
SHOULD TOP OUT IN THE 70S WITH MODEST MIXING OF THE BOUNDARY LAYER.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 320 AM CDT MON MAY 4 2015

PATTERN WILL REMAIN ACTIVE WITH SOUTHWEST FLOW ALOFT CONTINUING. BY
00Z THURSDAY A CLOSED LOW AT 500 MB SHOULD BE NEAR THE CA/OR BORDER
WITH A SHORTWAVE IN THE LARGE TROUGH TO OUR WEST EXTENDING FROM
MT DOWN INTO ERN KS. THAT SHOULD TEMPORARILY DECREASE OUR RAIN
CHANCES...AT LEAST SOMEWHAT...BUT NOT TO THE POINT WHERE WE CAN GO
DRY. THE CLOSED LOW OVER THE WESTERN STATES WILL DIG TOWARD THE
FOUR CORNERS REGION BY 12Z SATURDAY... THEN EJECT NORTHEAST
THROUGH THE PLAINS BY SUNDAY OR SUNDAY NIGHT. MONDAY IS PROBABLY
GOING TO BY DRY AS MOST ENERGY LIFTS NORTHEAST AND HIGH PRESSURE
AT THE SURFACE BUILDS IN WITH DRIER NORTHWEST SURFACE WINDS.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1222 PM CDT MON MAY 4 2015

RADAR MOSAIC THIS AFTN SHOWING SCT SHRA/ISOLD TS ACTIVITY LIFTING
NEWD ACROSS MOST OF NEB...AND EXPECTED ACTIVITY CONTINUE AT LEAST
THRU THIS EVENING OVER ERN NEB. ALL THIS IN PART TO POTENT UPPER
DISTURBANCE COUPLED WITH STALLED SFC BNDRY EXPECTED TO REMAIN
NEARLY STATIONARY ALONG THE NEB/KS BORDER INTO SRN IA. GIVEN
THIS...HAVE COVERED ALL TERMINALS WITH LATE AFTN/EARLY EVENING TEMPO
GROUPS IN ANTICIPATION OF MVFR CONDITIONS ACCOMPANYING ANY TSRA.
AFTN MIDNIGHT...AREAL COVERAGE WILL GRADUALLY DECREASE OVER ERN
NEB. IN ADDITIONS...THERE IS A SMALL CHANCE OF A TS APPROACHING
OR BECOMING SVR INVOF KLNK DURING THIS TIME.


FOR THIS
AFTN/EARLY EVENING PERIODS IN AN

&&

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

$$

SHORT TERM...PEARSON/MILLER
LONG TERM...MILLER
AVIATION...DEE



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