Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 310447
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1147 PM CDT THU JUL 30 2015

.UPDATE...
ISSUED AT 1138 PM CDT THU JUL 30 2015

UPDATED THE FORECAST EARLIER TO INCLUDE SOME ISO THUNDER MENTION
DOWN TO ABOUT I80 OVERNIGHT. EVENING UPPER AIR ANALYSIS INDICATED
A RIBBON OF 850 MB MOISTURE FROM WESTERN KS INTO NORTHEAST NEB.
MODELS INDICATE THAT SOME INCREASE IN THE LOW LEVEL JET IS
EXPECTED OVERNIGHT CREATED SOME CONVERGENCE OVER THIS MOISTURE AS
THIS BAND DROPS TO THE SOUTH THROUGH THE NIGHT. LIFTING A PARCEL
BETWEEN 850 AND 700 MB YIELDS AROUND 1500 J/KG AND ONLY AROUND
30-40 J/KG OF MUCIN. THUS SOME ISO ACTIVITY APPEARS POSSIBLE
OVERNIGHT...AS LATEST REGIONAL RADAR MOSAIC INDCS AS WELL. WE
EXPECT THIS ACTIVITY TO BE PRETTY ISO THOUGH WITH A FAIRLY WEAK
LOW LEVEL JET AND A LACK OF ANY LARGER-SCALE SUPPORT.

&&

.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 308 PM CDT THU JUL 30 2015

WARM AND DRIER WEATHER CONTINUES...BUT PERIODS OF SHOWERS AND
THUNDERSTORMS MAY DEVELOP TOMORROW INTO THE WEEKEND. SUBJECTIVE 12Z
UPPER AIR ANALYSIS INDICATES UPPER-LEVEL TROUGH STARTING TO SHOW
ITSELF IN EASTERN CANADA INTO THE GREAT LAKES...WITH RIDGING
DEVELOPING OVER THE GREAT BASIN...AND WEST TO WEST-NORTHWEST FLOW
ACROSS THE CENTRAL US.  UPPER-LEVEL JET STREAK OF UP TO 95KT WAS
NOTED ACROSS NEB/IA INTO THE GREAT LAKES.  DRIER AIRMASS HAS
PERSISTED...WITH 850MB HIGH CENTERED OVER EASTERN NEB/EASTERN
KS...AND 8C+ DEWPOINTS SUPPRESSED SOUTH OF AN AREA FROM NORTHWEST TO
SOUTHEAST KS AND NORTHERN AR.  RETURN FLOW WAS NOSING INTO THE HIGH
PLAINS...FEEDING CONVECTIVE DEVELOPMENT THIS AFTERNOON IN NORTHEAST
CO.  VIS SATELLITE IMAGERY INDICATED A FEW CU FROM NORTH CENTRAL TO
WESTERN NEB...WITH OTHERWISE MAINLY CLEAR SKIES ACROSS THE AREA.

MAIN FORECAST CONCERNS ARE POTENTIAL FOR
SHOWERS/STORMS...PARTICULARLY ON FRIDAY AFTERNOON/EVENING/NIGHT AND
AGAIN SATURDAY AFTERNOON/EVENING/NIGHT.  MODELS GENERALLY KEEP
CONVECTIVE DEVELOPMENT TODAY/TONIGHT IN CENTRAL/WESTERN NEB AND NOT
IN THE CWA...SO HAVE KEPT POPS OUT FOR TONIGHT.  INCREASING MID-
LEVEL MOISTURE ON FRIDAY SHOULD BE MORE SUPPORTIVE OF AFTERNOON
SHOWER/THUNDERSTORM DEVELOPMENT IN CENTRAL TO EASTERN NEB.  DESPITE
JUST A WEAK RIPPLE IN THE NORTHWESTERLY UPPER-LEVEL FLOW...AND WEAK
SURFACE CONVERGENCE...MODELS DEVELOP FAIRLY ROBUST CONVECTION IN
CENTRAL TO EASTERN NEB ON FRIDAY AFTERNOON...GROWING UPSCALE INTO AN
MCS THAT DIVES INTO KS IN THE EVENING/OVERNIGHT AND WITH SOME
SHOWERS/STORMS REDEVELOPING ON ITS OUTFLOW IN SOUTHERN IA TO CENTRAL
NEB THROUGH MORNING.  HAVE REFLECTED SOME OF THIS TIMING/PLACEMENT
IN REFINING POPS.  AFTER A BIT OF RECOVERY TIME...ALMOST THE SAME
PATTERN APPEARS...WITH AN EASTWARD SHIFT...AS CONVECTION DEVELOPS IN
EASTERN NEB/WESTERN IA...GROWS UPSCALE INTO AN MCS...THEN DROPS
SOUTH/SOUTHEASTWARD INTO MO OVERNIGHT.  INSTABILITY AND SHEAR ON
BOTH DAYS WOULD BE SUFFICIENT FOR AT LEAST A MARGINAL RISK OF SEVERE
WEATHER...THOUGH MOISTURE IS STILL SOMEWHAT LIMITED.  WITH WEAK
SURFACE WINDS...LOW-LEVEL SHEAR WOULD BE A NON-FACTOR.  TEMPERATURES
SHOULD WARM THROUGH SATURDAY...ASSUMING THAT THE FRIDAY NIGHT MCS
CLEARS WITH AMPLE TIME FOR RECOVERY...BUT AM LESS CONFIDENT ABOUT
RECOVERY AND WARMING ON SUNDAY GIVEN CONTINUED NORTHWEST UPPER-
LEVLE FLOW BUT ALSO SOME RETURN FLOW SNEAKING INTO THE WESTERN CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 308 PM CDT THU JUL 30 2015

INTERMITTENT CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE NEXT
WORK WEEK.  UPPER-LEVEL NORTHWESTERLY FLOW SHOULD TRANSITION TO MORE
ZONAL FLOW AS RIDGE SLIDES A BIT EASTWARD OUT OF THE ROCKIES...AND
MODELS INDICATE A FEW WAVES TOPPING THE RIDGE.  ANY OF THOSE WAVES
COULD GENERATE SHOWERS/THUNDERSTORMS ACROSS THE AREA...AS WELL AS
REINFORCE SLIGHTLY COOLER 850MB TEMPERATURES AS GRADIENT HANGS UP
NEAR THE CWA.  ALL IN ALL...HAVE SEVERAL PERIODS OF PRECIP
MENTIONED...WITH TEMPERATURES LINGERING BELOW NORMAL...BUT HAVE LOW
CONFIDENCE ON ANY GIVEN DAY.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1138 PM CDT THU JUL 30 2015

ISO SHRA/TSRA HAVE DEVELOPED BETWEEN KOMA/KOFK THIS EVNG...BUT IT
APPEARS UNLIKELY EITHER TAF SITE WILL BE IMPACTED OVERNIGHT OTHER
THAN AN INCREASE IN MID-LEVEL CLOUDS. A WEAK BOUNDARY IS STILL
EXPECTED TO DROP SWD THRU THE TAF SITES THROUGH THE DAY ON FRI AND
WE WILL LIKELY SEE SOME SHRA/TSRA DVLPMNT ALNG THIS BOUNDARY BY
MID AFTERNOON ON FRI LIKELY AFFECTING KOMA AND ESPECIALLY
KLNK...BUT SOUTH OF KOFK. WE MAY SEE SOME MVFR VISBY IN THIS
ACTIVITY. ANY SHRA ACTIVITY SHOULD END BY EARLY EVNG FRI AT THE
TAFS.

&&

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

&&

$$

UPDATE...BOUSTEAD
SHORT TERM...MAYES
LONG TERM...MAYES
AVIATION...BOUSTEAD


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