Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KOAX 250228
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
928 PM CDT FRI JUL 24 2015

.UPDATE...
ISSUED AT 917 PM CDT FRI JUL 24 2015

CLUSTER OF CONVECTION THAT FIRED ALONG THE COLD FRONT HAS WEAKENED
WITHIN THE LAST HOUR AS IT PUSHES OUT OF OUR AREA. KOAX 00Z UPPER
SOUNDING REVEALED 6021 J/KG OF CAPE...BUT WET BULB ZERO HEIGHTS
WERE ALSO ABOUT 13041 AGL...LIKELY RESULTING IN SIGNIFICANT MELTING
OF HAIL BEFORE IT HIT THE GROUND. STORMS PULSED UP AND DOWN VERY
QUICKLY...WITH MARGINAL WIND SHEAR TO GET LARGER HAIL TO DEVELOP.
WE DID HAVE SEVERAL PEA SIZE HAIL REPORTS...AND ONE NICKEL SIZE
HAIL REPORT NEAR BEATRICE. WINDS ALSO GUSTED TO 60 MPH AND DOWNED
A FEW TREES NEAR PLATTSMOUTH.

FOCUS SHIFTS TO THE WEST WITH STRONG STORMS DEVELOPING IN CENTRAL
NEBRASKA. THESE STORMS SHOULD CONTINUE TO DEVELOP EASTWARD THROUGH
THE PLATTE RIVER VALLEY OVERNIGHT...THUS HAVE INCREASED POPS IN
THIS AREA TO 50 TO 60 PERCENT. EFFECTIVE SHEAR OVERNIGHT SHOULD
REMAIN SOMEWHAT WEAK AT 25 TO 30 KNOTS...BUT VERY STRONG INSTABILITY
REMAINS ESPECIALLY SOUTHERN HALF OF THE FORECAST AREA. THUS ANY
STORMS OVERNIGHT MAY STILL CONTAIN GUSTY WINDS...AND MARGINALLY
SEVERE HAIL DUE TO HIGH WET BULB ZERO VALUES PREVIOUSLY MENTIONED.
FORTUNATELY...THIS ADDITIONAL RAINFALL SHOULD OCCUR OVER AREAS
THAT DID NOT RECEIVE RAIN EARLIER THIS EVENING. HOWEVER...THAT LINE
OF STORM DID PRODUCE RAINFALL OF 1 TO 2 INCHES...THUS WILL HAVE TO
WATCH A NARROW CORRIDOR THAT SAW THE STRONGER STORMS THIS EVENING.

UPDATE ISSUED AT 715 PM CDT FRI JUL 24 2015

THUNDERSTORMS ERUPTED ALONG THE COLD FRONT WITHIN THE LAST HOUR
TAKING ADVANTAGE OF 5000-6000 J/KG OF CAPE...ALTHOUGH EFFECT SHEAR
IS WEAK AT 20-25 KNOTS. STORMS HAVE BEEN VERY QUICK TO PULSE
UP...BUT ALSO PULSE RIGHT BACK DOWN.

&&

.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 320 PM CDT FRI JUL 24 2015

VERY HOT AND HUMID WEATHER WILL GIVE WAY TO CHANCES OF SHOWERS AND
THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS.  SUBJECTIVE 12Z UPPER
AIR ANALYSIS INDICATES BROAD UPPER-LEVEL RIDGE OVER THE CENTRAL
US...WITH A SHORTWAVE TROUGH RIDING AROUND THE EDGE OF THE RIDGE
OVER THE WESTERN GREAT LAKES...WITH WEAK UPPER-LEVEL JET AROUND 75KT
EXTENDING FROM NV INTO ND. 850MB MOISTURE WAS ABUNDANT ACROSS THE
CENTRAL US...WITH 12-20C DEWPOINTS FROM THE MID-MO RIVER VALLEY
SOUTHWARD.  SURFACE LOW AT 20Z WAS CENTERED IN SOUTHWEST CO...WITH
SECONDARY LOW IN NORTHERN MN...AND BOUNDARY EXTENDING BETWEEN THE
TWO THROUGH NORTHWEST IA/EASTERN NEB/CENTRAL KS.

MAIN FORECAST CONCERN IS CONVECTIVE POTENTIAL THIS EVENING AND
TONIGHT...AND AGAIN TOMORROW.  WILL LET HEAT ADVISORY RIDE AS IS
THROUGH 8PM...WITH WIDESPREAD AREA OF HEAT INDICES OF 105 OR
GREATER.  ELEVATED SHOWERS ONGOING IN CENTRAL NEB ARE MOVING INTO
MORE FAVORABLE AIRMASS OVER EASTERN NEB...BUT HAVE SHOWN SIGNS OF
WEAKENING.  SHORT-TERM CONVECTIVE-ALLOWING MODELS HAVE TENDED TO
KEEP THE CWA MAINLY PRECIP-FREE UNTIL LATER THIS EVENING...AFTER 03Z
OR EVEN 06Z...WITH THUNDERSTORMS EXPANDING OUT OF WESTERN NEB INTO
CENTRAL/EASTERN NEB AS THEY BOTH MOVE IN AND DEVELOP ALONG THE
BOUNDARY.  HINTS OF THIS ACTIVITY ARE ALREADY APPARENT...WITH
CONVECTIVE INITIATION SHOWING IN NORTHWEST KS. THAT SAID...FEW
MODELS ARE PICKING UP ON THE ELEVATED SHOWER/ISOLATED THUNDER
ACTIVITY THAT IS ONGOING. DID STILL DECREASE POPS FROM 00-
06Z...THOUGH KEPT A SLIGHT CHANCE MENTION UNTIL 03Z FOR THAT
ELEVATED SHOWERS/STORMS.  CONTINUED THE CHANCES FOR SHOWERS/STORMS
THROUGH TOMORROW NIGHT...THOUGH DID KEEP CHANCES ON THE LOWER
SIDE...AS CONFIDENCE IS ON THE LOW SIDE FOR WHERE AND WHEN
SHOWERS/STORMS WILL BE GOING.

SHOWERS/STORMS SHOULD CLEAR OUT OF THE AREA THROUGH SUNDAY
MORNING...LEAVING MAINLY FAIR WEATHER FOR AT LEAST THE AFTERNOON
HOURS AS THE SURFACE FRONT FINALLY PUSHES SOUTH OF THE AREA.
RESPITE IS SHORT-LIVED AS BOUNDARY BEGINS TO RETURN NORTHWARD
MONDAY...BRINGING A CHANCE FOR SHOWERS/STORMS AT LEAST INTO
SOUTHEAST TO CENTRAL NEB BY AROUND MONDAY MORNING AND INTO THE
AFTERNOON. TEMPERATURES ALSO WILL RETURN TO A WARMING TREND.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CDT FRI JUL 24 2015

THINK CHANCES OF SHOWERS/STORMS ON MONDAY NIGHT WILL SKIRT THE
NORTHWESTERN CWA AT BEST...WITH FOCUS MORE LIKELY TO BE FURTHER
NORTH AT THE NOSE OF THE LOW-LEVEL JET AND CLOSER TO THE APPROACHING
UPPER-LEVEL TROUGH.  FAIRLY SUBSTANTIAL TROUGH IS PROGGED TO MOVE
ACROSS THE NORTHERN CONUS ON TUESDAY...DRAGGING A COLD FRONT THROUGH
THE PLAINS.  CURRENT PROGS ADVANCE THE FRONT MAYBE INTO NORTHEAST
NEB BY 00Z WED. IN THE WARM SECTOR AHEAD OF THE FRONT...EXPECT TEMPS
TO JUMP WELL INTO THE 90S...AND HAVE CONTINUED TO PUSH TEMPERATURES
UP TO MATCH EXPECTATIONS.  ALSO KEPT POPS OUT OF THAT WARM
SECTOR...WHICH SHOULD BE STRONGLY CAPPED ON TUESDAY...AND LIMITED
SLIGHT CHANCE POPS TO ALONG AND BEHIND THE FRONT.  CHANCES INCREASE
ACROSS THE AREA ON TUESDAY NIGHT AS THE FRONT MOVES THROUGH...WITH
SOME POPS LINGERING INTO WED MORNING.  BEHIND THE FRONT...COOLER AND
DRIER AIRMASS SPILLS INTO THE CWA TO END THE WEEK.

&&

.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 720 PM CDT FRI JUL 24 2015

720 PM UPDATE...STORMS ERUPTED ALONG THE COLD FRONT JUST EAST OF
KLNK/KOMA BUT ARE MOVING EAST AWAY FROM THESE LOCATIONS. STILL
EXPECTING ADDITIONAL STORMS LATER IN THE NIGHT.

PREVIOUS DISCUSSION. TIMING OF STORMS INTO THE TAF SITES IS THE
PRIMARY PROBLEM THROUGH THE PERIOD. LOOKS LIKE STORMS COULD BE
NEAR KLNK BY 02-05Z... AND KOMA BY 03-06Z. NOT SURE IF STORMS WILL
MAKE IT ALL THE WAY NORTH TO KOFK. LINGERING SHOWERS COULD PERSIST
TILL 10-12Z. UNSURE OF ADDITIONAL CHANCES FOR STORMS BEYOND
THEN...BUT BEST CHANCES WOULD BE AT KLNK/KOMA.


&&

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

$$

UPDATE...DEWALD
SHORT TERM...MAYES
LONG TERM...MAYES
AVIATION...DEWALD



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.