Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 291158
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
658 AM CDT FRI AUG 29 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 325 AM CDT FRI AUG 29 2014

THE PRIMARY FORECAST CHALLENGES WILL BE IN REGARDS TO PCPN CHANCES
TODAY INTO TONIGHT AND THEN TIMING THE NEXT ROUND OF CONVECTION
SUNDAY INTO SUNDAY NIGHT. SOME SEVERE STORMS WILL BE POSSIBLE MAINLY
FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING.

MAIN FEATURES FROM THE UPPER AIR CHARTS LAST EVENING INCLUDED THE
FOLLOWING. AT 300 MB A JET SEGMENT OF AROUND 70 KNOTS WAS PUNCHING
NORTHEAST FROM SOUTHWEST KS. THIS WAS AHEAD OF A 500 MB TROUGH THAT
STRETCHED FROM THE DAKOTAS DOWN INTO WEST TEXAS. 12 HOUR HEIGHT
FALLS OF UP TO AROUND 40 METERS WERE NOTED AT AMARILLO AND DODGE
CITY. DECENT MOISTURE WAS STILL IN PLACE AT 700 MB AND 850 MB AHEAD
OF THE MID LEVEL TROUGH. THE KOAX SOUNDING WAS STILL FAIRLY MOIST
WITH 1.70 PRECIPITABLE WATER.

SURFACE ANALYSIS AT 08Z SHOWED LOW PRESSURE CENTERED OVER SOUTHEAST
SOUTH DAKOTA AND A COLD FRONT EXTENDING SOUTHWARD FROM THE LOW INTO
WEST TEXAS. DEWPOINTS WERE IN THE 60S TO LOWER 70S.

WATER VAPOR LOOP EARLY THIS MORNING SHOWED THAT THE TROUGH TO OUR
WEST HAD MADE SOME EASTWARD PROGRESS SINCE LAST EVENING. IT SHOULD
CONTINUE TO HAVE AN IMPACT ON US UNTIL A LITTLE AFTER MIDNIGHT
TONIGHT. KEPT FAIRLY HIGH POPS GOING TODAY...SINCE WE SHOULD SEE
REDEVELOPMENT THIS AFTERNOON WITH DAYTIME HEATING. FORECAST
SOUNDINGS FROM THE 00Z NAM INDICATED ELEVATED INSTABILITY OF OVER
2000 J/KG BY AROUND NOON. RECENT RUNS OF THE RAP MODEL SHOW AN
INCREASE IN PCPN COVERAGE AFTER 1 PM. HIGHS WILL BE MAINLY IN THE
UPPER 70S AND LOWER 80S. LOWS TONIGHT SHOULD DROP TO THE LOWER AND
MID 60S AS DRIER AIR WORKS ITS WAY IN FROM THE NORTHWEST BEHIND THE
COLD FRONT. SOME PATCHY FOG COULD DEVELOP LATE TONIGHT...BUT OVERALL
THE ATMOSPHERE WILL BE DRYING OUT.

SATURDAY LOOKS LIKE A DECENT DAY WITH A FAIR AMOUNT OF SUNSHINE AND
HIGHS IN THE 80S. CLOUDS WILL START TO INCREASE SATURDAY NIGHT...
ESPECIALLY IN OUR FAR WESTERN ZONES. KEPT A SMALL CHANCE OF LATE
NIGHT TSTMS IN NORTHEAST NEBRASKA.

MODELS HAVE SOME TIMING DIFFERENCES FOR SUNDAY INTO SUNDAY NIGHT.
KEPT SOME LOW POPS LATE SATURDAY NIGHT WEST OF A LINE FROM WAYNE TO
COLUMBUS. 00Z RUNS OF THE NAM AND CANADIAN MODEL WERE A BIT SLOWER
WITH DEVELOPMENT OF STORMS SUNDAY AFTERNOON. FOR NOW...BLENDED IN
SOME OF THE GFS AND ECMWF WHICH SHOW SOME RAINFALL AMOUNTS OVER A
QUARTER OF AN INCH SUNDAY AFTERNOON. IF THE NAM IS MORE CORRECT...
THE SEVERE WEATHER POTENTIAL IS PROBABLY HIGHER SUNDAY EVENING THAN
IF THE GFS AND ECMWF VERIFY BETTER. LOOK FOR HIGHS MAINLY IN THE
80S AND MAYBE NEAR 90 FOR PARTS OF SOUTHEAST NEBRASKA.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 AM CDT FRI AUG 29 2014

TRENDED POPS DOWNWARD SUNDAY NIGHT FROM NORTHWEST TO SOUTHEAST AS
THE SYSTEM MOVES THROUGH...BUT LINGERED A SLIGHT CHANCE OF TSTMS
INTO MONDAY MORNING.

A 500 MB LONGWAVE TROUGH AXIS WILL BE LOCATED OVER THE EASTERN
ROCKIES AND WESTERN HIGH PLAINS AT THE BEGINNING OF THIS PERIOD.
BY TUESDAY...THAT SHIFTS EAST OF OUR AREA AND THEN THE FLOW IS
FAIRLY ZONAL ACROSS MID AMERICA INTO WEDNESDAY. LATER IN THE WEEK
ANOTHER TROUGH WILL DIG INTO THE PACIFIC NORTHWEST...WITH OUR
AREA UNDER THE INFLUENCE OF SOUTHWEST MID LEVEL FLOW. ALTHOUGH
THUNDERSTORM CHANCES WILL NOT BE COMPLETELY ABSENT...NEXT WEEK
SHOULD BE A LOT DRIER THAN THIS WEEK HAS BEEN. HIGHS WILL MODERATE
FROM MAINLY 80S TO AROUND 90 AND LOWS WILL INCREASE FROM 60S TO
AROUND 70 OR THE LOWER 70S.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 624 AM CDT FRI AUG 29 2014

LATEST OBS SHOWING MID LVL CIGS PREVAILING OVER ERN NEB THIS
MORNING WITH -SHRA MOVING NWD OUT OF ERN KS. EXPECT ACTIVITY WILL
DIMINISH WITHIN THE NEXT COUPLE HOURS...THUS HAVE ADDED TEMPO
GROUPS TO KOMA/KLNK. MEANWHILE...A STALLED FRONTAL BNDRY
EXTENDING FROM NW IA TO CNTRL KS WILL BE THE FOCUS FOR CONVECTIVE
REDEVELOPMENT LATE THIS AFTN. AREAL COVERAGE IS IN QUESTION AT
THIS POINT...THUS OPTED FOR PROB30 GROUPS. VFR CONDITIONS THEN
DURING THE EVENING AND OVERNIGHT HOURS.


&&

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

$$

SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...DEE


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