000
FXUS63 KOAX 211732
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1232 PM CDT TUE MAY 21 2013
.DISCUSSION...
BUMPED UP CLOUD COVER SIGNIFICANTLY FROM PREVIOUS FORECAST AND
DROPPED TEMPS JUST A COUPLE OF DEGREES. ALSO BROUGHT CHANCE OF
SHOWERS A LITTLE FURTHER SOUTH WHERE CYCLONIC FLOW IS A LITTLE
STRONGER.
&&
.AVIATION...18Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS
EXPECTED AT KOMA/KLNK...BUT LIKELY BECOMING MVFR BY 00-03Z...WHICH
SHOULD CONTINUE THROUGH THE REMAINDER OF THE FORECAST. KOFK WILL
LIKELY REMAIN MVFR THROUGH 00-03Z...WITH SPOTTY SHOWERS IN THE
VICINITY OF THE TAF SITE...THEN BECOMING IFR BY 06-09Z. WINDS WILL
BE WEST SOUTHWEST...THEN NORTHWEST...WITH SUSTAINED SPEEDS 12 TO
15 KNOTS...GUSTS UP TO 25 TO 28 KNOTS THROUGH 23-01Z.
&&
.PREV DISCUSSION... /ISSUED 323 AM CDT TUE MAY 21 2013/
DISCUSSION...
QUIET WEATHER ACROSS THE AREA THIS MORNING AS UPPER LOW SPINS
NEARBY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES BROAD UPPER LOW
CENTERED IN NORTHEAST SD/SOUTHEAST ND...WITH UPPER-LEVEL RIDGE FROM
NORTHERN CA THROUGH CENTRAL SASK. UPPER-LEVEL JET STREAK UP TO 95KT
EXTENDED FROM TX/OK PANHANDLES TO NORTHWEST MO. DEEP 850MB LOW WAS
CENTERED IN EASTERN ND/NORTHWEST MN...WITH TRAILING COLD FRONT
THROUGH CENTRAL NEB/CENTRAL KS/WESTERN OK...AND WARM FRONT EXTENDING
FROM LOW ACROSS NORTHERN MN/NORTHERN WI/UP OF MI. 850MB DEWPOINTS
OF 8C+ COVERED THE BROAD AREA AHEAD OF THE FRONTS...WITH DRIER AIR
ALSO INTO NEB/IA/NORTHEAST KS/NORTHWEST MO. SURFACE LOW AT 07Z WAS
CENTERED IN NORTHEAST SD...WITH TRAILING COLD FRONT ALONG THE MO
RIVER VALLEY.
MAIN FORECAST CONCERNS INCLUDE POTENTIAL FOR SHOWERS IN THE
NORTHEAST CWA TONIGHT/WEDNESDAY...THEN THUNDERSTORM POTENTIAL FRIDAY
THROUGH MONDAY NIGHT. FORECAST SOUNDINGS INDICATE MORE STABILITY
TODAY THAN YESTERDAY...AND THINK CWA WILL AVOID SHOWERS DURING THE
DAY...THOUGH CLOUDS WILL INCREASE. MAY SEE A SHOWER SKIRT THE
NORTHEAST CWA TONIGHT AS UPPER LOW DROPS OUT OF THE DAKOTAS TOWARD
NORTHWEST IA...BUT THINK SOUNDINGS STILL LOOK TOO STABLE FOR
THUNDER...AND HAVE KEPT PRECIP MENTION LIMITED TO SHOWERS.
WEDNESDAY NIGHT AND THURSDAY LOOK QUIET AS UPPER LOW MOVES SLOWLY
EASTWARD...WITH MID- TO UPPER-LEVEL RIDGING MOVING INTO THE CENTRAL
PLAINS. TEMPS WILL REMAIN ON THE COOLER SIDE THROUGH THURSDAY...BUT
AS SOUTHERLY FLOW RETURNS TO THE AREA FRIDAY...TEMPERATURES WILL
MODERATE TO NEAR OR ABOVE NORMAL.
WHILE UPPER-LEVEL RIDGING IS EXPECTED TO LINGER OVER THE CENTRAL US
THROUGH THE WEEKEND...A MID-LEVEL WARM FRONT IS PROGGED TO DEVELOP
ACROSS THE AREA ON SATURDAY. ECMWF PROG INDICATES FRONT WOULD THEN
SAG SOUTHWARD ON SUNDAY...WHILE GFS HINTS AT FRONT LIFTING NORTH.
WARM AIR ADVECTION ON FRIDAY AFTERNOON/EVENING COULD BE ENOUGH TO
KICK UP SOME SHOWERS/THUNDERSTORMS...WITH ADDITIONAL SHOWERS/STORMS
ALONG THE FRONT ON SATURDAY. WOULD EXPECT A DRY PERIOD OR TWO AS
FRONT SLIPS SOUTHWARD OUT OF THE AREA...WITH THUNDERSTORM ACTIVITY
FOCUSING ON THE HIGH PLAINS AS WELL AS IN A CORRIDOR ALONG THE
FRONT. MODEL BLENDS HAVE SPRAYED THE ENTIRE EXTENDED PERIOD WITH
CHANCE POPS...BUT HAVE TRIED TO PULL BACK TO SLIGHT CHANCE IN
PERIODS THAT LOOK LESS FAVORABLE FOR SHOWERS/STORMS. UNCERTAINTY
INCREASES FOR MONDAY/TUESDAY...AS BEST FORCING FOR STORMS STILL
LOOKS TO REMAIN WEST OF HERE...BUT RIDGE BEGINS TO WEAKEN AND WAVES
MOVE THROUGH THE RIDGING.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
DEWALD
000
FXUS63 KOAX 211130
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
630 AM CDT TUE MAY 21 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
CLOUDS WILL CONTINUE TO MOVE DOWN ACROSS THE AREA AS MOISTURE
WRAPS AROUND THE MID LEVEL LOW PRESSURE SYSTEM OVER THE NORTHERN
PLAINS. SOME MVFR CEILINGS WILL OCCUR THIS MORNING...ESPECIALLY
AT KOFK. CEILINGS SHOULD RISE A BIT THIS AFTERNOON AT KLNK AND
KOMA AS SOME HEATING OCCURS...BUT CEILINGS AT KOFK WILL LIKELY
REMAIN IN THE MVFR CATEGORY. TONIGHT...CEILINGS WILL BE ON THE
DECREASE...DROPPING TO MVFR AT KOMA AND KLNK. SOME IFR CEILINGS AR
POSSIBLE AT KOFK...MAINLY AFTER 06Z. SOME OCCASIONAL -SHRA MAY
ALSO OCCUR AT KOFK THROUGH THE PERIOD...BUT CHANCES WERE NOT HIGH
ENOUGH TO MENTION IN THE TAF FOR NOW.
MILLER
&&
.PREV DISCUSSION... /ISSUED 323 AM CDT TUE MAY 21 2013/
DISCUSSION...
QUIET WEATHER ACROSS THE AREA THIS MORNING AS UPPER LOW SPINS
NEARBY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES BROAD UPPER LOW
CENTERED IN NORTHEAST SD/SOUTHEAST ND...WITH UPPER-LEVEL RIDGE FROM
NORTHERN CA THROUGH CENTRAL SASK. UPPER-LEVEL JET STREAK UP TO 95KT
EXTENDED FROM TX/OK PANHANDLES TO NORTHWEST MO. DEEP 850MB LOW WAS
CENTERED IN EASTERN ND/NORTHWEST MN...WITH TRAILING COLD FRONT
THROUGH CENTRAL NEB/CENTRAL KS/WESTERN OK...AND WARM FRONT EXTENDING
FROM LOW ACROSS NORTHERN MN/NORTHERN WI/UP OF MI. 850MB DEWPOINTS
OF 8C+ COVERED THE BROAD AREA AHEAD OF THE FRONTS...WITH DRIER AIR
ALSO INTO NEB/IA/NORTHEAST KS/NORTHWEST MO. SURFACE LOW AT 07Z WAS
CENTERED IN NORTHEAST SD...WITH TRAILING COLD FRONT ALONG THE MO
RIVER VALLEY.
MAIN FORECAST CONCERNS INCLUDE POTENTIAL FOR SHOWERS IN THE
NORTHEAST CWA TONIGHT/WEDNESDAY...THEN THUNDERSTORM POTENTIAL FRIDAY
THROUGH MONDAY NIGHT. FORECAST SOUNDINGS INDICATE MORE STABILITY
TODAY THAN YESTERDAY...AND THINK CWA WILL AVOID SHOWERS DURING THE
DAY...THOUGH CLOUDS WILL INCREASE. MAY SEE A SHOWER SKIRT THE
NORTHEAST CWA TONIGHT AS UPPER LOW DROPS OUT OF THE DAKOTAS TOWARD
NORTHWEST IA...BUT THINK SOUNDINGS STILL LOOK TOO STABLE FOR
THUNDER...AND HAVE KEPT PRECIP MENTION LIMITED TO SHOWERS.
WEDNESDAY NIGHT AND THURSDAY LOOK QUIET AS UPPER LOW MOVES SLOWLY
EASTWARD...WITH MID- TO UPPER-LEVEL RIDGING MOVING INTO THE CENTRAL
PLAINS. TEMPS WILL REMAIN ON THE COOLER SIDE THROUGH THURSDAY...BUT
AS SOUTHERLY FLOW RETURNS TO THE AREA FRIDAY...TEMPERATURES WILL
MODERATE TO NEAR OR ABOVE NORMAL.
WHILE UPPER-LEVEL RIDGING IS EXPECTED TO LINGER OVER THE CENTRAL US
THROUGH THE WEEKEND...A MID-LEVEL WARM FRONT IS PROGGED TO DEVELOP
ACROSS THE AREA ON SATURDAY. ECMWF PROG INDICATES FRONT WOULD THEN
SAG SOUTHWARD ON SUNDAY...WHILE GFS HINTS AT FRONT LIFTING NORTH.
WARM AIR ADVECTION ON FRIDAY AFTERNOON/EVENING COULD BE ENOUGH TO
KICK UP SOME SHOWERS/THUNDERSTORMS...WITH ADDITIONAL SHOWERS/STORMS
ALONG THE FRONT ON SATURDAY. WOULD EXPECT A DRY PERIOD OR TWO AS
FRONT SLIPS SOUTHWARD OUT OF THE AREA...WITH THUNDERSTORM ACTIVITY
FOCUSING ON THE HIGH PLAINS AS WELL AS IN A CORRIDOR ALONG THE
FRONT. MODEL BLENDS HAVE SPRAYED THE ENTIRE EXTENDED PERIOD WITH
CHANCE POPS...BUT HAVE TRIED TO PULL BACK TO SLIGHT CHANCE IN
PERIODS THAT LOOK LESS FAVORABLE FOR SHOWERS/STORMS. UNCERTAINTY
INCREASES FOR MONDAY/TUESDAY...AS BEST FORCING FOR STORMS STILL
LOOKS TO REMAIN WEST OF HERE...BUT RIDGE BEGINS TO WEAKEN AND WAVES
MOVE THROUGH THE RIDGING.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 210823
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
323 AM CDT TUE MAY 21 2013
.DISCUSSION...
QUIET WEATHER ACROSS THE AREA THIS MORNING AS UPPER LOW SPINS
NEARBY. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES BROAD UPPER LOW
CENTERED IN NORTHEAST SD/SOUTHEAST ND...WITH UPPER-LEVEL RIDGE FROM
NORTHERN CA THROUGH CENTRAL SASK. UPPER-LEVEL JET STREAK UP TO 95KT
EXTENDED FROM TX/OK PANHANDLES TO NORTHWEST MO. DEEP 850MB LOW WAS
CENTERED IN EASTERN ND/NORTHWEST MN...WITH TRAILING COLD FRONT
THROUGH CENTRAL NEB/CENTRAL KS/WESTERN OK...AND WARM FRONT EXTENDING
FROM LOW ACROSS NORTHERN MN/NORTHERN WI/UP OF MI. 850MB DEWPOINTS
OF 8C+ COVERED THE BROAD AREA AHEAD OF THE FRONTS...WITH DRIER AIR
ALSO INTO NEB/IA/NORTHEAST KS/NORTHWEST MO. SURFACE LOW AT 07Z WAS
CENTERED IN NORTHEAST SD...WITH TRAILING COLD FRONT ALONG THE MO
RIVER VALLEY.
MAIN FORECAST CONCERNS INCLUDE POTENTIAL FOR SHOWERS IN THE
NORTHEAST CWA TONIGHT/WEDNESDAY...THEN THUNDERSTORM POTENTIAL FRIDAY
THROUGH MONDAY NIGHT. FORECAST SOUNDINGS INDICATE MORE STABILITY
TODAY THAN YESTERDAY...AND THINK CWA WILL AVOID SHOWERS DURING THE
DAY...THOUGH CLOUDS WILL INCREASE. MAY SEE A SHOWER SKIRT THE
NORTHEAST CWA TONIGHT AS UPPER LOW DROPS OUT OF THE DAKOTAS TOWARD
NORTHWEST IA...BUT THINK SOUNDINGS STILL LOOK TOO STABLE FOR
THUNDER...AND HAVE KEPT PRECIP MENTION LIMITED TO SHOWERS.
WEDNESDAY NIGHT AND THURSDAY LOOK QUIET AS UPPER LOW MOVES SLOWLY
EASTWARD...WITH MID- TO UPPER-LEVEL RIDGING MOVING INTO THE CENTRAL
PLAINS. TEMPS WILL REMAIN ON THE COOLER SIDE THROUGH THURSDAY...BUT
AS SOUTHERLY FLOW RETURNS TO THE AREA FRIDAY...TEMPERATURES WILL
MODERATE TO NEAR OR ABOVE NORMAL.
WHILE UPPER-LEVEL RIDGING IS EXPECTED TO LINGER OVER THE CENTRAL US
THROUGH THE WEEKEND...A MID-LEVEL WARM FRONT IS PROGGED TO DEVELOP
ACROSS THE AREA ON SATURDAY. ECMWF PROG INDICATES FRONT WOULD THEN
SAG SOUTHWARD ON SUNDAY...WHILE GFS HINTS AT FRONT LIFTING NORTH.
WARM AIR ADVECTION ON FRIDAY AFTERNOON/EVENING COULD BE ENOUGH TO
KICK UP SOME SHOWERS/THUNDERSTORMS...WITH ADDITIONAL SHOWERS/STORMS
ALONG THE FRONT ON SATURDAY. WOULD EXPECT A DRY PERIOD OR TWO AS
FRONT SLIPS SOUTHWARD OUT OF THE AREA...WITH THUNDERSTORM ACTIVITY
FOCUSING ON THE HIGH PLAINS AS WELL AS IN A CORRIDOR ALONG THE
FRONT. MODEL BLENDS HAVE SPRAYED THE ENTIRE EXTENDED PERIOD WITH
CHANCE POPS...BUT HAVE TRIED TO PULL BACK TO SLIGHT CHANCE IN
PERIODS THAT LOOK LESS FAVORABLE FOR SHOWERS/STORMS. UNCERTAINTY
INCREASES FOR MONDAY/TUESDAY...AS BEST FORCING FOR STORMS STILL
LOOKS TO REMAIN WEST OF HERE...BUT RIDGE BEGINS TO WEAKEN AND WAVES
MOVE THROUGH THE RIDGING.
MAYES
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
EXTENSIVE LOW TO MID CLOUD DECK CONTINUES TO MOVE THROUGH BROAD
CYCLONIC FLOW INTO EASTERN NEBRASKA. THIS WILL SPREAD OVER ALL TAF
SITES OVERNIGHT WITH CIGS LIKELY GOING FROM VFR DOWN TO MVFR. A FEW
SCATTERED LIGHT RAIN SHOWERS ARE POSSIBLE BUT TOO SMALL OF A CHANCE
TO FEEL THE NEED TO INCLUDE IN THE TAFS.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 210343
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1043 PM CDT MON MAY 20 2013
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
EXTENSIVE LOW TO MID CLOUD DECK CONTINUES TO MOVE THROUGH BROAD
CYCLONIC FLOW INTO EASTERN NEBRASKA. THIS WILL SPREAD OVER ALL TAF
SITES OVERNIGHT WITH CIGS LIKELY GOING FROM VFR DOWN TO MVFR. A FEW
SCATTERED LIGHT RAIN SHOWERS ARE POSSIBLE BUT TOO SMALL OF A CHANCE
TO FEEL THE NEED TO INCLUDE IN THE TAFS.
KERN
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT MON MAY 20 2013/
DISCUSSION...
FORECAST CONCERNS OVER THE NEXT FEW DAYS WILL MAINLY BE SPORADIC
SHOWERS...AND ISOLATED THUNDERSHOWERS THIS EVENING...THEN
TEMPERATURES.
AT 12Z A SEASONABLY STRONG H30 JET WITH 80 TO 100KT WINDS DOVE
SOUTH THROUGH UTAH ACROSS NORTHERN NEW MEXICO AND THE TEXAS
PANHANDLE AN RE-CURVES NORTHEAST ACROSS IOWA. THE FORECAST AREA IS
UNDER THE INFLUENCE OF A LARGE AREA OF CLOSED LOW PRESSURE
CENTERED OVER SOUTH DAKOTA AND NORTHERN NEBRASKA...THAT ELONGATES
BACK ACROSS COLORADO. THE H7 AND H85 WERE SIMILARLY VERTICALLY
STACKED. DECENT MOISTURE WAS NOTED PER THE 12Z KLBF RAOB TO 440MB
AND THE KOAX RAOBS TO 560MB.
BY LATE AFTERNOON AND TONIGHT...THE H5 LOW WILL REMAIN IN THE
SAME LOCATION...THEN GRADUALLY WEAKEN AND SEND SOME ENERGY AROUND
THE LOW. CONVECTIVE TEMPERATURES ARE IN THE UPPER 70S AND THERE IS
SOME MID LEVEL WARM ADVECTION THROUGH THE EVENING. THE ATMOSPHERE HAS
BECOME CONVECTIVELY UNSTABLE WITH SURFACE BASED CAPE 500-1000
J/KG. A FEW SHOWERS HAVE DEVELOPED AND SOME THUNDERSTORMS COULD
ALSO DEVELOP. ALTHOUGH THE COVERAGE MAY BE TOUGH TO PIN DOWN...THE
OPERATIONAL/EXPERIMENTAL MODELS ARE SPLIT WITH SOME DRY AND
OTHERS GENERATING SOME ISOLD TO SCATTERED PRECIP. LOOKING AT THE
NAM/HRRR/RAP/HOPWRF ENSEMBLES/4KM WRF/GFS TEND TO FOCUS THE HIGHER
PRECIP CHANCES OVER THE FAR SOUTHEAST NEB AND SOUTHWEST IOWA
COUNTIES OR IN THE NORTHWEST EARLY THIS EVENING WITH ISOLD
ELSEWHERE...WITH A GENERAL DOWNWARD TREND IN AND LOCAL PRECIP
AFTER SUNSET.
WE CONTINUE TO BE UNDER THE INFLUENCE OF CYCLONIC FLOW THROUGH
WEDNESDAY...THUS A CLOUDY AND COOLER PERIOD WITH SOME CHANCE OF
SHOWERS. ANY PRECIPITATION SHOULD BE ON THE LIGHT SIDE. HIGHS
TUESDAY AND WEDNESDAY IN THE 60S AND 70S. WE SEE A BREAK WITH
RIDGING OVER THE AREA WEDNESDAY NIGHT THROUGH THURSDAY NIGHT
HOWEVER CLOUDS WILL BE ON THE INCREASE. THE NEXT CHANCE FOR
THUNDERSTORMS WILL BE FRIDAY AND LAST INTO THE WEEKEND. THE 12Z
EURO IS A LITTLE MORE PROGRESSIVE WITH THE WEATHER AND DRIES IT
OUT BY SATURDAY AFTERNOON. SO...THE SAT AFTERNOON INTO MONDAY
FORECAST WILL LIKELY SEE SOME ADJUSTMENT AS THE LONG RANGE MODELS
COME INTO BETTER AGREEMENT.
CZ
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 202332
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
632 PM CDT MON MAY 20 2013
.AVIATION...00Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CONDITIONS ARE EXPECTED INITIALLY BUT CEILINGS ARE FORECAST TO
LOWER TO MVFR OVERNIGHT AS AN EXTENSIVE CLOUD DECK DROPS SOUTHEAST
ON THE BACKSIDE OF A SLOWLY DEPARTING LOW PRESSURE SYSTEM. A FEW
PATCHY IFR CIGS CANNOT BE RULED OUT DURING THE OVERNIGHT AND EARLY
MORNING HOURS. LIGHT SHOWERS ARE EXPECTED INTO KOFK DURING THE
EVENING HOURS BUT THESE SHOULD BEGIN TO DISSIPATE AS THEY CONTINUE
TO DROP SOUTHEAST. DO EXPECT A BROKEN TO OVERCAST MID LEVEL CLOUD
DECK THROUGHOUT THE DAY TUESDAY.
KERN
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT MON MAY 20 2013/
DISCUSSION...
FORECAST CONCERNS OVER THE NEXT FEW DAYS WILL MAINLY BE SPORDIC
SHOWERS...AND ISOLATED THUNDERSHOWERS THIS EVENING...THEN
TEMPERATURES.
AT 12Z A SEASONABLY STRONG H30 JET WITH 80 TO 100KT WINDS DOVE
SOUTH THROUGH UTAH ACROSS NORTHERN NEW MEXICO AND THE TEXAS
PANHANDLE AN RE-CURVES NORTHEAST ACROSS IOWA. THE FORECAST AREA IS
UNDER THE INFLUENCE OF A LARGE AREA OF CLOSED LOW PRESSURE
CENTERED OVER SOUTH DAKOTA AND NORTHERN NEBRASKA...THAT ELONGATES
BACK ACROSS COLORADO. THE H7 AND H85 WERE SIMILARLY VERTICALLY
STACKED. DECENT MOISTURE WAS NOTED PER THE 12Z KLBF RAOB TO 440MB
AND THE KOAX RAOBS TO 560MB.
BY LATE AFTERNOON AND TONIGHT...THE H5 LOW WILL REMAIN IN THE
SAME LOCATION...THEN GRADUALLY WEAKEN AND SEND SOME ENERGY AROUND
THE LOW. CONVECTIVE TEMPERATURES ARE IN THE UPPER 70S AND THERE IS
SOME MID LEVEL WARM ADVECTION THROUGH THE EVENING. THE ATMOSPHERE HAS
BECOME CONVECTIVELY UNSTABLE WITH SURFACE BASED CAPE 500-1000
J/KG. A FEW SHOWERS HAVE DEVELOPED AND SOME THUNDERSTORMS COULD
ALSO DEVELOP. ALTHOUGH THE COVERAGE MAY BE TOUGH TO PIN DOWN...THE
OPERATIONAL/EXPERIMENTAL MODELS ARE SPLIT WITH SOME DRY AND
OTHERS GENERATING SOME ISOLD TO SCATTERED PRECIP. LOOKING AT THE
NAM/HRRR/RAP/HOPWRF ENSEMBLES/4KM WRF/GFS TEND TO FOCUS THE HIGHER
PRECIP CHANCES OVER THE FAR SOUTHEAST NEB AND SOUTHWEST IOWA
COUNTIES OR IN THE NORTHWEST EARLY THIS EVENING WITH ISOLD
ELSEWHERE...WITH A GENERAL DOWNWARD TREND IN AND LOCAL PRECIP
AFTER SUNSET.
WE CONTINUE TO BE UNDER THE INFLUENCE OF CYCLONIC FLOW THROUGH
WEDNESDAY...THUS A CLOUDY AND COOLER PERIOD WITH SOME CHANCE OF
SHOWERS. ANY PRECIPITATION SHOULD BE ON THE LIGHT SIDE. HIGHS
TUESDAY AND WEDNESDAY IN THE 60S AND 70S. WE SEE A BREAK WITH
RIDGING OVER THE AREA WEDNESDAY NIGHT THROUGH THURSDAY NIGHT
HOWEVER CLOUDS WILL BE ON THE INCREASE. THE NEXT CHANCE FOR
THUNDERSTORMS WILL BE FRIDAY AND LAST INTO THE WEEKEND. THE 12Z
EURO IS A LITTLE MORE PROGRESSIVE WITH THE WEATHER AND DRIES IT
OUT BY SATURDAY AFTERNOON. SO...THE SAT AFTERNOON INTO MONDAY
FORECAST WILL LIKELY SEE SOME ADJUSTMENT AS THE LONG RANGE MODELS
COME INTO BETTER AGREEMENT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 202040
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
340 PM CDT MON MAY 20 2013
.DISCUSSION...
FORECAST CONCERNS OVER THE NEXT FEW DAYS WILL MAINLY BE SPORDIC
SHOWERS...AND ISOLATED THUNDERSHOWERS THIS EVENING...THEN
TEMPERATURES.
AT 12Z A SEASONABLY STRONG H30 JET WITH 80 TO 100KT WINDS DOVE
SOUTH THROUGH UTAH ACROSS NORTHERN NEW MEXICO AND THE TEXAS
PANHANDLE AN RE-CURVES NORTHEAST ACROSS IOWA. THE FORECAST AREA IS
UNDER THE INFLUENCE OF A LARGE AREA OF CLOSED LOW PRESSURE
CENTERED OVER SOUTH DAKOTA AND NORTHERN NEBRASKA...THAT ELONGATES
BACK ACROSS COLORADO. THE H7 AND H85 WERE SIMILARLY VERTICALLY
STACKED. DECENT MOISTURE WAS NOTED PER THE 12Z KLBF RAOB TO 440MB
AND THE KOAX RAOBS TO 560MB.
BY LATE AFTERNOON AND TONIGHT...THE H5 LOW WILL REMAIN IN THE
SAME LOCATION...THEN GRADUALLY WEAKEN AND SEND SOME ENERGY AROUND
THE LOW. CONVECTIVE TEMPERATURES ARE IN THE UPPER 70S AND THERE IS
SOME MID LEVEL WARM ADVECTION THROUGH THE EVENING. THE ATMOSPHERE HAS
BECOME CONVECTIVELY UNSTABLE WITH SURFACE BASED CAPE 500-1000
J/KG. A FEW SHOWERS HAVE DEVELOPED AND SOME THUNDERSTORMS COULD
ALSO DEVELOP. ALTHOUGH THE COVERAGE MAY BE TOUGH TO PIN DOWN...THE
OPERATIONAL/EXPERIMENTAL MODELS ARE SPLIT WITH SOME DRY AND
OTHERS GENERATING SOME ISOLD TO SCATTERED PRECIP. LOOKING AT THE
NAM/HRRR/RAP/HOPWRF ENSEMBLES/4KM WRF/GFS TEND TO FOCUS THE HIGHER
PRECIP CHANCES OVER THE FAR SOUTHEAST NEB AND SOUTHWEST IOWA
COUNTIES OR IN THE NORTHWEST EARLY THIS EVENING WITH ISOLD
ELSEWHERE...WITH A GENERAL DOWNWARD TREND IN AND LOCAL PRECIP
AFTER SUNSET.
WE CONTINUE TO BE UNDER THE INFLUENCE OF CYCLONIC FLOW THROUGH
WEDNESDAY...THUS A CLOUDY AND COOLER PERIOD WITH SOME CHANCE OF
SHOWERS. ANY PRECIPITATION SHOULD BE ON THE LIGHT SIDE. HIGHS
TUESDAY AND WEDNESDAY IN THE 60S AND 70S. WE SEE A BREAK WITH
RIDGING OVER THE AREA WEDNESDAY NIGHT THROUGH THURSDAY NIGHT
HOWEVER CLOUDS WILL BE ON THE INCREASE. THE NEXT CHANCE FOR
THUNDERSTORMS WILL BE FRIDAY AND LAST INTO THE WEEKEND. THE 12Z
EURO IS A LITTLE MORE PROGRESSIVE WITH THE WEATHER AND DRIES IT
OUT BY SATURDAY AFTERNOON. SO...THE SAT AFTERNOON INTO MONDAY
FORECAST WILL LIKELY SEE SOME ADJUSTMENT AS THE LONG RANGE MODELS
COME INTO BETTER AGREEMENT.
&&
.AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY MORNING.
SCATTERED TO BROKEN CUMULUS NEAR FL050 IS FORECAST THROUGH THE
AFTERNOON. A FEW SHOWERS OR ISOLATED THUNDERSTORMS COULD DEVELOP
BRINGING MVFR CONDITIONS TO SOME AREAS. HOWEVER CHANCES AT TAF
SITES ARE RATHER SLIM. PRECIPITATION SHOULD DISSIPATE WITH THE
SETTING SUN...THEN CIGS NEAR FL040 WILL OVERSPREAD EASTERN
NEBRASKA FROM THE NORTH. SOME MVFR CIGS ARE POSSIBLE IN NORTHEAST
NEBRASKA NEAR KOFK AFTER 06Z...BUT HAVE LEFT OUT OF TAF FORECAST
AT THE MOMENT.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
000
FXUS63 KOAX 201716
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1216 PM CDT MON MAY 20 2013
.UPDATE...
FORECAST IS GENERALLY ON TRACK FOR THIS AFTERNOON. SURFACE-BASED
CAPE VALUES ARE STILL EXPECTED INTO THE 500-1000 J/KG RANGE LATE
TODAY IN THE SOUTHEAST HALF OF THE CWA...ALONG WITH MODERATE
EFFECTIVE BULK SHEAR AROUND 40KT. A SURFACE TROUGH WAS NOTED IN
CENTRAL NEBRASKA...AND RAP FORECAST SUGGEST THIS WILL BE SWEEPING
ACROSS EASTERN NEBRASKA BEFORE 00Z. SO THE COMBINATION OF WEAK
INSTABILITY WITH MODERATE SHEAR AND A FOCUSING MECHANISM SHOULD
RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS DRIVEN BY AFTERNOON
HEATING. SMALL HAIL AND GUSTY WINDS ARE POSSIBLE GIVEN LAPSE RATES
APPROACHING 8C IN OUR FAR SOUTHEAST AND MODEST TEMP-DEW POINT
DEPRESSIONS.
DERGAN
&&
.AVIATION...18Z TAFS FOR KOFK...KLNK AND KOMA.
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY MORNING.
SCATTERED TO BROKEN CUMULUS NEAR FL050 IS FORECAST THROUGH THE
AFTERNOON. A FEW SHOWERS OR ISOLATED THUNDERSTORMS COULD DEVELOP
BRINGING MVFR CONDITIONS TO SOME AREAS. HOWEVER CHANCES AT TAF
SITES ARE RATHER SLIM. PRECIPITATION SHOULD DISSIPATE WITH THE
SETTING SUN...THEN CIGS NEAR FL040 WILL OVERSPREAD EASTERN
NEBRASKA FROM THE NORTH. SOME MVFR CIGS ARE POSSIBLE IN NORTHEAST
NEBRASKA NEAR KOFK AFTER 06Z...BUT HAVE LEFT OUT OF TAF FORECAST
AT THE MOMENT.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 323 AM CDT MON MAY 20 2013/
DISCUSSION...
THE UPPER LEVEL LOW CURRENTLY CENTERED OVER NE NEB AND ERN SD WILL
CONTINUE TO BE THE MAIN FORECAST ISSUE THROUGH THE SHORT TERM.
BROAD Q-G FORCING FOR ASCENT UNDER THE UPPER LEVEL LOW WAS
LEADING TO SCATTERED SHOWERS OVER CENTRAL AND NE NEB EARLY THIS
MORNING. THIS SHOULD CONT IN NE NEB WITH MOST OF THE CENTRAL AND
SOUTHERN CWA DRY THIS MORNING. SOME SUN IS EXPECTED TODAY OVER
THIS AREA OF THE CWA /SW IA AND SE NEB/ THAT WILL STEEPEN LOW
LEVEL LAPSE RATES. GIVEN THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
ACROSS THIS AREA AND THE COLD MID LEVEL TEMPERATURES UNDER THE
UPPER LEVEL LOW...THE ATMOSPHERE SHOULD BECOME WEAKLY UNSTABLE
THIS AFTERNOON WITH AROUND 400-600 J/KG OF SBCAPE OVER THE CNTRL
AND SRN CWA. THIS SHOULD LEAD TO SCATTERED AFTERNOON SHOWERS AND
ISO THUNDERSTORMS ACROSS THE FA. SEVERE WEATHER GENERALLY SEEMS
UNLIKELY...BUT WITH THE STEEP MID LEVEL LAPSE RATES AND MODERATE
SHEAR SOME HAIL SEEMS POSSIBLE IF SUFFICIENT HEATING CAN TAKE
PLACE THROUGH THE MORNING. OTHERWISE THE SHOWERS AND ISO TSRA
SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME
HEATING. THE SETUP FOR TUESDAY ISN`T AS FAVORABLE FOR AFTERNOON
TSRA AS THE LOW LEVEL RESIDUAL MOISTURE GETS DISPLACED TO THE EAST
AS CAA MOVES THROUGH THE FA BEHIND A SFC CDFNT ON MON NIGHT. THIS
WILL LEAD TO SEASONABLY COOL TEMPERATURES FOR TUE/WED. WE MAY SEE
AN ISO SHOWER IN THE NRN FA UNDER THE UPPER LEVEL LOW...BUT THESE
WILL BE PRETTY ISOLATED.
THE LOW FINALLY STARTS TO SHIFT EAST ON THU WITH DRY WEATHER
RETURNING...BUT THIS WILL ONLY BE FOR A SHORT TIME AS LONGER RANGE
MODELS ARE FAIRLY CONSISTENT IN BRINGING IN A TROUGH TO THE
WESTERN US WITH WAA TYPE PRECIP DEVELOPING STARTING ON FRI AND
INTO NEXT WEEKEND. WITH THE RETURN FLOW TEMPERATURES WILL ALSO BE
RETURNING TO NEAR NORMAL AS WELL.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 201137
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
637 AM CDT MON MAY 20 2013
.AVIATION...
12Z TAFS FOR KOMA...KLNK...AND KOFK.
A SWATH OF MVFR CEILINGS MAY BRUSH ANY OF THE TAF SITES THIS
MORNING...WITH THE HIGHEST LIKELIHOOD AT KOMA. THE LOWER CEILINGS
WILL BREAK BY MID-MORNING...WITH SCT TO BKN MID-LEVEL CLOUDS
THROUGH THE REST OF THE DAY. HAVE INCLUDED A TEMPO MENTION AT
KOMA/KLNK FOR SHOWERS THIS AFTERNOON...AND WHILE CONFIDENCE IN
COVERAGE IS TOO LOW TO MENTION...WOULD NOT BE SURPRISED BY THUNDER
WITH THESE SHOWERS. HAVE KEPT VFR CEILINGS OVERNIGHT...THOUGH
WORTH NOTING THAT MODELS HINT AT MVFR CEILINGS AGAIN LATE IN THE
PERIOD. WINDS WILL BECOME SOUTHWESTERLY AND INCREASE BY LATE
MORNING...THEN DIMINISH AFTER SUNSET.
MAYES
&&
.PREV DISCUSSION... /ISSUED 323 AM CDT MON MAY 20 2013/
DISCUSSION...
THE UPPER LEVEL LOW CURRENTLY CENTERED OVER NE NEB AND ERN SD WILL
CONTINUE TO BE THE MAIN FORECAST ISSUE THROUGH THE SHORT TERM.
BROAD Q-G FORCING FOR ASCENT UNDER THE UPPER LEVEL LOW WAS
LEADING TO SCATTERED SHOWERS OVER CENTRAL AND NE NEB EARLY THIS
MORNING. THIS SHOULD CONT IN NE NEB WITH MOST OF THE CENTRAL AND
SOUTHERN CWA DRY THIS MORNING. SOME SUN IS EXPECTED TODAY OVER
THIS AREA OF THE CWA /SW IA AND SE NEB/ THAT WILL STEEPEN LOW
LEVEL LAPSE RATES. GIVEN THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
ACROSS THIS AREA AND THE COLD MID LEVEL TEMPERATURES UNDER THE
UPPER LEVEL LOW...THE ATMOSPHERE SHOULD BECOME WEAKLY UNSTABLE
THIS AFTERNOON WITH AROUND 400-600 J/KG OF SBCAPE OVER THE CNTRL
AND SRN CWA. THIS SHOULD LEAD TO SCATTERED AFTERNOON SHOWERS AND
ISO THUNDERSTORMS ACROSS THE FA. SEVERE WEATHER GENERALLY SEEMS
UNLIKELY...BUT WITH THE STEEP MID LEVEL LAPSE RATES AND MODERATE
SHEAR SOME HAIL SEEMS POSSIBLE IF SUFFICIENT HEATING CAN TAKE
PLACE THROUGH THE MORNING. OTHERWISE THE SHOWERS AND ISO TSRA
SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME
HEATING. THE SETUP FOR TUESDAY ISN`T AS FAVORABLE FOR AFTERNOON
TSRA AS THE LOW LEVEL RESIDUAL MOISTURE GETS DISPLACED TO THE EAST
AS CAA MOVES THROUGH THE FA BEHIND A SFC CDFNT ON MON NIGHT. THIS
WILL LEAD TO SEASONABLY COOL TEMPERATURES FOR TUE/WED. WE MAY SEE
AN ISO SHOWER IN THE NRN FA UNDER THE UPPER LEVEL LOW...BUT THESE
WILL BE PRETTY ISOLATED.
THE LOW FINALLY STARTS TO SHIFT EAST ON THU WITH DRY WEATHER
RETURNING...BUT THIS WILL ONLY BE FOR A SHORT TIME AS LONGER RANGE
MODELS ARE FAIRLY CONSISTENT IN BRINGING IN A TROUGH TO THE
WESTERN US WITH WAA TYPE PRECIP DEVELOPING STARTING ON FRI AND
INTO NEXT WEEKEND. WITH THE RETURN FLOW TEMPERATURES WILL ALSO BE
RETURNING TO NEAR NORMAL AS WELL.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KOAX 200823
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
323 AM CDT MON MAY 20 2013
.DISCUSSION...
THE UPPER LEVEL LOW CURRENTLY CENTERED OVER NE NEB AND ERN SD WILL
CONTINUE TO BE THE MAIN FORECAST ISSUE THROUGH THE SHORT TERM.
BROAD Q-G FORCING FOR ASCENT UNDER THE UPPER LEVEL LOW WAS
LEADING TO SCATTERED SHOWERS OVER CENTRAL AND NE NEB EARLY THIS
MORNING. THIS SHOULD CONT IN NE NEB WITH MOST OF THE CENTRAL AND
SOUTHERN CWA DRY THIS MORNING. SOME SUN IS EXPECTED TODAY OVER
THIS AREA OF THE CWA /SW IA AND SE NEB/ THAT WILL STEEPING LOW
LEVEL LAPSE RATES. GIVEN THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
ACROSS THIS AREA AND THE COLD MID LEVEL TEMPERATURES UNDER THE
UPPER LEVEL LOW...THE ATMOSPHERE SHOULD BECOME WEAKLY UNSTABLE
THIS AFTERNOON WITH AROUND 400-600 J/KG OF SBCAPE OVER THE CNTRL
AND SRN CWA. THIS SHOULD LEAD TO SCATTERED AFTERNOON SHOWERS AND
ISO THUNDERSTORMS ACROSS THE FA. SEVERE WEATHER GENERALLY SEEMS
UNLIKELY...BUT WITH THE STEEP MID LEVEL LAPSE RATES AND MODERATE
SHEAR SOME HAIL SEEMS POSSIBLE IF SUFFICIENT HEATING CAN TAKE
PLACE THROUGH THE MORNING. OTHERWISE THE SHOWERS AND ISO TSRA
SHOULD DIMINISH QUICKLY THIS EVENING WITH THE LOSS OF DAYTIME
HEATING. THE SETUP FOR TUESDAY ISN`T AS FAVORABLE FOR AFTERNOON
TSRA AS THE LOW LEVEL RESIDUAL MOISTURE GETS DISPLACED TO THE
EAST AS CAA MOVES THROUGH THE FA BEHIND A SFC CDFNT ON MON NIGHT.
THIS WILL LEAD TO SEASONABLY COOL TEMPERATURES FOR TUE/WED. WE MAY
SEE AN ISO SHOWER IN THE NRN FA UNDER THE UPPER LEVEL LOW...BUT
THESE WILL BE PRETTY ISOLATED.
THE LOW FINALLY STARTS TO SHIFT EAST ON THU WITH DRY WEATHER
RETURNING...BUT THIS WILL ONLY BE FOR A SHORT TIME AS LONGER RANGE
MODELS ARE FAIRLY CONSISTENT IN BRINGING IN A TROUGH TO THE
WESTERN US WITH WAA TYPE PRECIP DEVELOPING STARTING ON FRI AND
INTO NEXT WEEKEND. WITH THE RETURN FLOW TEMPERATURES WILL ALSO BE
RETURNING TO NEAR NORMAL AS WELL.
BOUSTEAD
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
AN UPPER LOW FM NCNTRL NEBR INTO WRN SD WILL CONTINUE TO CIRCULATE
OVER THE REGION THROUGH MONDAY. SHOWERS AND ISOLATED THUNDERSTORMS
AND CIGS AT TIMES AROUND 1-2K FT AGL WILL ROTATE AROUND THE
SYSTEM TONIGHT...PROBABLY MAINLY JUST IMPACTING KOFK. AT THIS TIME
IT APPEARED SURFACE WINDS ROTATING AROUND SYSTEM WILL CONTINUE TO
FEED LOWER LEVEL DRY AIR TOWARD LNK AND OMA. HOWEVER...IF WINDS
REMAIN LIGHT ENOUGH MUCH OF THE NIGHT...SOME FOG COULD FORM LATER
TONIGHT AT THOSE SITES. HEATING ON MONDAY COULD CAUSE ADDITIONAL
SHOWER AND ISOLATED TSTM DEVELOPMENT. COVERAGE OF TSTMS MON AFTN
WAS UNCERTAIN AND ONLY A PROB30 IN SHOWERS WERE MENTIONED IN 06Z
FORECAST.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 200428
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1128 PM CDT SUN MAY 19 2013
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
AN UPPER LOW FM NCNTRL NEBR INTO WRN SD WILL CONTINUE TO CIRCULATE
OVER THE REGION THROUGH MONDAY. SHOWERS AND ISOLATED THUNDERSTORMS
AND CIGS AT TIMES AROUND 1-2K FT AGL WILL ROTATE AROUND THE
SYSTEM TONIGHT...PROBABLY MAINLY JUST IMPACTING KOFK. AT THIS TIME
IT APPEARED SURFACE WINDS ROTATING AROUND SYSTEM WILL CONTINUE TO
FEED LOWER LEVEL DRY AIR TOWARD LNK AND OMA. HOWEVER...IF WINDS
REMAIN LIGHT ENOUGH MUCH OF THE NIGHT...SOME FOG COULD FORM LATER
TONIGHT AT THOSE SITES. HEATING ON MONDAY COULD CAUSE ADDITIONAL
SHOWER AND ISOLATED TSTM DEVELOPMENT. COVERAGE OF TSTMS MON AFTN
WAS UNCERTAIN AND ONLY A PROB30 IN SHOWERS WERE MENTIONED IN 06Z
FORECAST.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT SUN MAY 19 2013/
DISCUSSION...
SHORT TERM FORECAST CONCERNS WILL BE ONGOING SEVERE WEATHER THEN
LINGERING THUNDERSTORMS LATER TONIGHT AND SHOWER AND
THUNDERSTORMS WITH THE CYCLONIC FLOW AROUND THE SLOW MOVING H5 LOW
OVER THE DAKOTAS THROUGH WEDNESDAY.
AS OF MID AFTERNOON...HAVE A COUPLE OF TORNADO WATCHES IN EFFECT
FOR PARTS OF SOUTHEAST NEBRASKA INTO WESTERN IOWA.
THE MORNING OAX SOUNDING...WE STILL HAD AROUND 1 INCH OF
PRECIPITABLE WITH STEEP MID LEVEL LAPSE RATES OF 7.6C/KM. AT
H300...THERE IS AN EXTENDED 90-110KT JET FROM THE WEST COAST TO THE
TEXAS PANHANDLE. THIS JET IS FORECAST TO PROGRESS ACROSS OKLAHOMA
TODAY AND CURVE NORTHEAST TO IOWA AND MINNESOTA TONIGHT...WITH UPPER
LEVEL DIVERGENCE FROM NORTHEAST KS...THEN MISSOURI TO EASTERN IOWA
AND WISCONSIN OVERNIGHT. THE H5 LOW WAS CENTERED OVER WY AND SD
WITH AREAS OF VORTICITY ROTATING NORTHEASTWARD AROUND THE LOW THRU
THE H5 FLOW. THE AREA OF LOW PRESSURE OVER WYOMING IS FORECAST TO
DUMBELL...AND ROTATE INTO NEBRASKA AND THEN NORTHEAST AGAIN INTO
EASTERN SOUTH DAKOTA...AND THEN NORTH DAKOTA DURING THE DAY MONDAY.
THIS WILL CAUSE HEIGHT FALLS OVER THE PLAINS TODAY...THE UPPER
MIDWEST TONIGHT AND THE UPPER MISSISSIPPI VALLEY MONDAY. AT H7/H8
THESE WERE NEARLY STACKED AREAS OF LOW PRESSURE CENTERED OVER THE
SD/ND BORDER WITH LOW PRESSURE EXTENDING SOUTHWARD TOWARD THE NEB/KS
BORDER. THE CAPPING H7 TEMPERATURES WERE WELL TO THE SOUTH IN OK
AND SOUTHERN MO AND THE BELT OF STRONGER H85 45 TO 50 KT WINDS
STRETCHED FROM TEXAS TOWARD MISSOURI. THE SWATH OF DEEPER MOISTURE
EXTENDED FROM TX ACROSS OK INTO KS WITH POCKETS IN NEBRASKA.
BY THE START OF THE EVENING PERIOD...INSTABILITY IS EXPECTED TO
RANGE FROM 1000-2500J/KG WITH 0-6KM BULK SHEAR OF 30 TO 55KTS
OVER THE SOUTHEAST THIRD OF THE FORECAST AREA. PER THE SPC
MESOANALYSIS...THE MOST UNSTABLE SURFACE BASED INSTABILITY WAS
LOCATED OVER SOUTH CENTRAL KANSAS AT 2030Z. COMPLEX SHORT WAVE
ENERGY WILL PIVOT NORTHEAST AND ROTATING AROUND THE H5 LOWS. WE
HAVE ONE LINE OF THUNDERSTORMS MOVING THROUGH NOW...HOWEVER INSTABILITY
WILL CONTINUE TO BE DRAWN NORTHWARD INTO THE EARLY EVENING HOURS.
THE GENERAL SOUTHWEST TO NORTHEAST FLOW WILL VEER MORE WITH TIME
.THEN DRYING OF THE DEEP MOISTURE WITH AN EASTWARD SHIFT OF THE
ORGANIZED SEVERE WEATHER. THAT BEING SAID...MOISTURE WILL CONTINUE
TO ROTATE AROUND THE UPPER WITH SOME SHOWER AND THUNDERSTORMS
ACTIVITY ROTATING BACK INTO PARTS OF THE AREA OVERNIGHT. THE MID
TROPOSPHERIC LOW WILL REMAIN OVER THE DAKOTAS MONDAY AND TUESDAY
AND WILL WILL KEEP THE AREA UNDER THE RISK FOR SHOWERS AND
ISOLATED THUNDERSTORMS. HIGHEST POPS WILL BE OVER NORTHEAST
NEBRASKA DURING THIS TIME FRAME. MONDAY THROUGH WEDNESDAY WILL SEE
COOLER TEMPERATURES WILL HIGHS IN THE 60S AND 70S.
DURING THE EXTENDED AS ANOTHER CYCLONE SPINS OVER THE PACIFIC
NORTHWEST...DEEPER MOISTURE WILL RETURN TO THE PLAINS. THIS TOO IS
A SLOW MOVING SYSTEM AND WILL BRING SHOWERS AND THUNDERSTORMS TO
THE REGION FRIDAY INTO SUNDAY.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 192344
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
644 PM CDT SUN MAY 19 2013
.AVIATION...
..00Z TAFS FOR KOFK...KLNK AND KOMA.
ALL THREE TAF SITES SOMEWHAT BETWEEN TWO AREAS OF THUNDERSTORMS.
THE WARM SECTOR THUNDERSTORMS EXTENDED FROM EXTREME SOUTHEAST
NEBRASKA...ACROSS SOUTHWEST IOWA CONTINUING INTO CENTRAL
IOWA. THUNDERSTORMS ASSOCIATED WITH THE ACTUAL COLD FRONT EXTEND
FROM JUST WEST OF KOFK SOUTHWARD TO COLUMBUS...CONTINUING SOUTH TO
THE KANSAS BORDER. HAVE COVERED NEXT ROUND OF THUNDERSTORMS IN ALL
THREE TAFS WITH APPROPRIATE TEMPO GROUPS. EXPECT THUNDERSTORMS TO
MOVE EAST OF ALL THREE TAF SITES AFTER 06Z. SOME LINGERING SHOWERS
AND SOME PATCHY FOG CAN BE EXPECTED AFTER THUNDERSTORMS EXIT THE
AREA.
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT SUN MAY 19 2013/
DISCUSSION...
SHORT TERM FORECAST CONCERNS WILL BE ONGOING SEVERE WEATHER THEN
LINGERING THUNDERSTORMS LATER TONIGHT AND SHOWER AND
THUNDERSTORMS WITH THE CYCLONIC FLOW AROUND THE SLOW MOVING H5 LOW
OVER THE DAKOTAS THROUGH WEDNESDAY.
AS OF MID AFTERNOON...HAVE A COUPLE OF TORNADO WATCHES IN EFFECT
FOR PARTS OF SOUTHEAST NEBRASKA INTO WESTERN IOWA.
THE MORNING OAX SOUNDING...WE STILL HAD AROUND 1 INCH OF
PRECIPITABLE WITH STEEP MID LEVEL LAPSE RATES OF 7.6C/KM. AT
H300...THERE IS AN EXTENDED 90-110KT JET FROM THE WEST COAST TO THE
TEXAS PANHANDLE. THIS JET IS FORECAST TO PROGRESS ACROSS OKLAHOMA
TODAY AND CURVE NORTHEAST TO IOWA AND MINNESOTA TONIGHT...WITH UPPER
LEVEL DIVERGENCE FROM NORTHEAST KS...THEN MISSOURI TO EASTERN IOWA
AND WISCONSIN OVERNIGHT. THE H5 LOW WAS CENTERED OVER WY AND SD
WITH AREAS OF VORTICITY ROTATING NORTHEASTWARD AROUND THE LOW THRU
THE H5 FLOW. THE AREA OF LOW PRESSURE OVER WYOMING IS FORECAST TO
DUMBELL...AND ROTATE INTO NEBRASKA AND THEN NORTHEAST AGAIN INTO
EASTERN SOUTH DAKOTA...AND THEN NORTH DAKOTA DURING THE DAY MONDAY.
THIS WILL CAUSE HEIGHT FALLS OVER THE PLAINS TODAY...THE UPPER
MIDWEST TONIGHT AND THE UPPER MISSISSIPPI VALLEY MONDAY. AT H7/H8
THESE WERE NEARLY STACKED AREAS OF LOW PRESSURE CENTERED OVER THE
SD/ND BORDER WITH LOW PRESSURE EXTENDING SOUTHWARD TOWARD THE NEB/KS
BORDER. THE CAPPING H7 TEMPERATURES WERE WELL TO THE SOUTH IN OK
AND SOUTHERN MO AND THE BELT OF STRONGER H85 45 TO 50 KT WINDS
STRETCHED FROM TEXAS TOWARD MISSOURI. THE SWATH OF DEEPER MOISTURE
EXTENDED FROM TX ACROSS OK INTO KS WITH POCKETS IN NEBRASKA.
BY THE START OF THE EVENING PERIOD...INSTABILITY IS EXPECTED TO
RANGE FROM 1000-2500J/KG WITH 0-6KM BULK SHEAR OF 30 TO 55KTS
OVER THE SOUTHEAST THIRD OF THE FORECAST AREA. PER THE SPC
MESOANALYSIS...THE MOST UNSTABLE SURFACE BASED INSTABILITY WAS
LOCATED OVER SOUTH CENTRAL KANSAS AT 2030Z. COMPLEX SHORT WAVE
ENERGY WILL PIVOT NORTHEAST AND ROTATING AROUND THE H5 LOWS. WE
HAVE ONE LINE OF THUNDERSTORMS MOVING THROUGH NOW...HOWEVER INSTABILITY
WILL CONTINUE TO BE DRAWN NORTHWARD INTO THE EARLY EVENING HOURS.
THE GENERAL SOUTHWEST TO NORTHEAST FLOW WILL VEER MORE WITH TIME
..THEN DRYING OF THE DEEP MOISTURE WITH AN EASTWARD SHIFT OF THE
ORGANIZED SEVERE WEATHER. THAT BEING SAID...MOISTURE WILL CONTINUE
TO ROTATE AROUND THE UPPER WITH SOME SHOWER AND THUNDERSTORMS
ACTIVITY ROTATING BACK INTO PARTS OF THE AREA OVERNIGHT. THE MID
TROPOSPHERIC LOW WILL REMAIN OVER THE DAKOTAS MONDAY AND TUESDAY
AND WILL WILL KEEP THE AREA UNDER THE RISK FOR SHOWERS AND
ISOLATED THUNDERSTORMS. HIGHEST POPS WILL BE OVER NORTHEAST
NEBRASKA DURING THIS TIME FRAME. MONDAY THROUGH WEDNESDAY WILL SEE
COOLER TEMPERATURES WILL HIGHS IN THE 60S AND 70S.
DURING THE EXTENDED AS ANOTHER CYCLONE SPINS OVER THE PACIFIC
NORTHWEST...DEEPER MOISTURE WILL RETURN TO THE PLAINS. THIS TOO IS
A SLOW MOVING SYSTEM AND WILL BRING SHOWERS AND THUNDERSTORMS TO
THE REGION FRIDAY INTO SUNDAY.
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KOAX 192042
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
342 PM CDT SUN MAY 19 2013
.DISCUSSION...
SHORT TERM FORECAST CONCERNS WILL BE ONGOING SEVERE WEATHER THEN
LINGERING THUNDERSTORMS LATER TONIGHT AND SHOWER AND
THUNDERSTORMS WITH THE CYCLONIC FLOW AROUND THE SLOW MOVING H5 LOW
OVER THE DAKOTAS THROUGH WEDNESDAY.
AS OF MID AFTERNOON...HAVE A COUPLE OF TORNADO WATCHES IN EFFECT
FOR PARTS OF SOUTHEAST NEBRASKA INTO WESTERN IOWA.
THE MORNING OAX SOUNDING...WE STILL HAD AROUND 1 INCH OF
PRECIPITABLE WITH STEEP MID LEVEL LAPSE RATES OF 7.6C/KM. AT
H300...THERE IS AN EXTENDED 90-110KT JET FROM THE WEST COAST TO THE
TEXAS PANHANDLE. THIS JET IS FORECAST TO PROGRESS ACROSS OKLAHOMA
TODAY AND CURVE NORTHEAST TO IOWA AND MINNESOTA TONIGHT...WITH UPPER
LEVEL DIVERGENCE FROM NORTHEAST KS...THEN MISSOURI TO EASTERN IOWA
AND WISCONSIN OVERNIGHT. THE H5 LOW WAS CENTERED OVER WY AND SD
WITH AREAS OF VORTICITY ROTATING NORTHEASTWARD AROUND THE LOW THRU
THE H5 FLOW. THE AREA OF LOW PRESSURE OVER WYOMING IS FORECAST TO
DUMBELL...AND ROTATE INTO NEBRASKA AND THEN NORTHEAST AGAIN INTO
EASTERN SOUTH DAKOTA...AND THEN NORTH DAKOTA DURING THE DAY MONDAY.
THIS WILL CAUSE HEIGHT FALLS OVER THE PLAINS TODAY...THE UPPER
MIDWEST TONIGHT AND THE UPPER MISSISSIPPI VALLEY MONDAY. AT H7/H8
THESE WERE NEARLY STACKED AREAS OF LOW PRESSURE CENTERED OVER THE
SD/ND BORDER WITH LOW PRESSURE EXTENDING SOUTHWARD TOWARD THE NEB/KS
BORDER. THE CAPPING H7 TEMPERATURES WERE WELL TO THE SOUTH IN OK
AND SOUTHERN MO AND THE BELT OF STRONGER H85 45 TO 50 KT WINDS
STRETCHED FROM TEXAS TOWARD MISSOURI. THE SWATH OF DEEPER MOISTURE
EXTENDED FROM TX ACROSS OK INTO KS WITH POCKETS IN NEBRASKA.
BY THE START OF THE EVENING PERIOD...INSTABILITY IS EXPECTED TO
RANGE FROM 1000-2500J/KG WITH 0-6KM BULK SHEAR OF 30 TO 55KTS
OVER THE SOUTHEAST THIRD OF THE FORECAST AREA. PER THE SPC
MESOANALYSIS...THE MOST UNSTABLE SURFACE BASED INSTABILITY WAS
LOCATED OVER SOUTH CENTRAL KANSAS AT 2030Z. COMPLEX SHORT WAVE
ENERGY WILL PIVOT NORTHEAST AND ROTATING AROUND THE H5 LOWS. WE
HAVE ONE LINE OF THUNDERSTORMS MOVING THROUGH NOW...HOWEVER INSTABILITY
WILL CONTINUE TO BE DRAWN NORTHWARD INTO THE EARLY EVENING HOURS.
THE GENERAL SOUTHWEST TO NORTHEAST FLOW WILL VEER MORE WITH TIME
...THEN DRYING OF THE DEEP MOISTURE WITH AN EASTWARD SHIFT OF THE
ORGANIZED SEVERE WEATHER. THAT BEING SAID...MOISTURE WILL CONTINUE
TO ROTATE AROUND THE UPPER WITH SOME SHOWER AND THUNDERSTORMS
ACTIVITY ROTATING BACK INTO PARTS OF THE AREA OVERNIGHT. THE MID
TROPOSPHERIC LOW WILL REMAIN OVER THE DAKOTAS MONDAY AND TUESDAY
AND WILL WILL KEEP THE AREA UNDER THE RISK FOR SHOWERS AND
ISOLATED THUNDERSTORMS. HIGHEST POPS WILL BE OVER NORTHEAST
NEBRASKA DURING THIS TIME FRAME. MONDAY THROUGH WEDNESDAY WILL SEE
COOLER TEMPERATURES WILL HIGHS IN THE 60S AND 70S.
DURING THE EXTENDED AS ANOTHER CYCLONE SPINS OVER THE PACIFIC
NORTHWEST...DEEPER MOISTURE WILL RETURN TO THE PLAINS. THIS TOO IS
A SLOW MOVING SYSTEM AND WILL BRING SHOWERS AND THUNDERSTORMS TO
THE REGION FRIDAY INTO SUNDAY.
&&
.AVIATION...
..18Z TAFS FOR KOFK...KLNK AND KOMA.
SCATTERED THUNDERSTORMS COULD AFFECT ALL EASTERN NEBRASKA TAF
SITES THROUGH THE EVENING. KOFK WILL SEE SCATTERED THUNDERSTORMS
THROUGH ABOUT 21Z BEFORE A BREAK IN THE ACTION THERE. AT KLNK AND
KOMA...MOST STORMS WILL REMAIN WEST OF THE TAF SITE THROUGH 00Z
BEFORE A BAND OF STORMS SWEEPS THROUGH. WHILE STORMS COULD POP AT
JUST ABOUT ANY TIME DURING THE AFTERNOON AND EVENING...TAFS WERE
WRITTEN TO INCLUDE A 2 TO 4 HOUR WINDOW OF MOST LIKELY STORM
ACTIVITY. EACH ROUND OF STORMS WILL BRING AT LEAST MVFR
CONDITIONS...BUT IFR CIGS/VSBYS CAN BE EXPECTED WITHIN
THUNDERSTORM AREAS. MOST OF THE ACTIVITY SHOULD BE MOVING EAST OF
TAF SITES BY 04-06Z TIME FRAME...BUT MORE SHOWERS WILL LIKELY
FILTER INTO KOFK FROM THE NORTHWEST AFTER 06Z. VFR CONDITIONS ARE
EXPECTED OUTSIDE OF ANY PRECIPITATION.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
000
FXUS63 KOAX 191729
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1229 PM CDT SUN MAY 19 2013
.AVIATION...18Z TAFS FOR KOFK...KLNK AND KOMA.
SCATTERED THUNDERSTORMS COULD AFFECT ALL EASTERN NEBRASKA TAF
SITES THROUGH THE EVENING. KOFK WILL SEE SCATTERED THUNDERSTORMS
THROUGH ABOUT 21Z BEFORE A BREAK IN THE ACTION THERE. AT KLNK AND
KOMA...MOST STORMS WILL REMAIN WEST OF THE TAF SITE THROUGH 00Z
BEFORE A BAND OF STORMS SWEEPS THROUGH. WHILE STORMS COULD POP AT
JUST ABOUT ANY TIME DURING THE AFTERNOON AND EVENING...TAFS WERE
WRITTEN TO INCLUDE A 2 TO 4 HOUR WINDOW OF MOST LIKELY STORM
ACTIVITY. EACH ROUND OF STORMS WILL BRING AT LEAST MVFR
CONDITIONS...BUT IFR CIGS/VSBYS CAN BE EXPECTED WITHIN
THUNDERSTORM AREAS. MOST OF THE ACTIVITY SHOULD BE MOVING EAST OF
TAF SITES BY 04-06Z TIME FRAME...BUT MORE SHOWERS WILL LIKELY
FILTER INTO KOFK FROM THE NORTHWEST AFTER 06Z. VFR CONDITIONS ARE
EXPECTED OUTSIDE OF ANY PRECIPITATION.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 1132 AM CDT SUN MAY 19 2013/
UPDATE...
A COUPLE OF VORTICITY MAXIMA WERE NOTED ON SATELLITE AND RADAR LATE
THIS MORNING...ONE LIFTING NORTH INTO NORTHWEST IOWA...AND ANOTHER
MOVING NORTHEAST INTO NORTH CENTRAL NEBRASKA. EASTERN VORT WAS
TAKING SHOWERS AND ISOLATED THUNDERSTORMS WITH IT...SO EXPECT A FEW
MORE HOURS OF PESKY SHOWERS IN WEST CENTRAL IOWA. TO THE
WEST...SHOWERS AND THUNDERSTORMS WERE BEGINNING TO FIRE ALONG A
SPOKE OF VORTICITY AROUND WESTERN CENTER...BUBBLING UP IN OUR FAR
WESTERN CWA. NOT EXPECTING ANYTHING MAJOR WITH THESE STORMS AS
INSTABILITY HAS REMAINED IN CHECK DUE TO LINGERING MORNING RAINS.
HOWEVER INSTABILITY IS EXPECTED TO INCREASE MARKEDLY ACROSS A GOOD
PART OF EASTERN NEBRASKA AND WESTERN IOWA THIS AFTERNOON AS
SOUTHERLY FLOW DRAWS MOISTENING LOW LEVEL AIR NORTH AND MID LEVEL
TEMPERATURES COOL WITH APPROACH OF UPPER TROUGH/LOW. MID LEVEL LAPSE
RATES GREATER THAN 8 C/KM ARE EXPECTED. RAP CAPE FORECASTS SUGGEST
SURFACE BASED VALUES WILL APPROACH 2500 J/KG OVER THE SOUTHERN HALF
OF OUR CWA WHERE SUNSHINE IS MOST LIKELY AND SOUTH OF WARM FRONTAL
BOUNDARY SLOWLY LIFTING TOWARD OR JUST NORTH OF INTERSTATE 80 BY MID
AFTERNOON. SHEAR PROFILES WILL BE WEAKENING WITH TIME WITH APPROACH
OF UPPER/SURFACE LOWS...BUT 40 TO 50KT OF 0-6KM BULK SHEAR IS STILL
EXPECTED ACROSS SOUTHEAST NEBRASKA THROUGH 00Z..COINCIDENT WITH
RELATIVE MAXIMUM IN CAPE FIELD. AND 0-1KM STORM-RELATIVE HELICITY
APPROACHES 120. SO AT LEAST MODERATE INSTABILITY WILL BRING A HAIL
THREAT TO MUCH OF THE SOUTHEAST HALF OF THE CWA...WHILE SHEAR
PROFILES ARE MORE FAVORABLE TO A VARIETY OF SEVERE MODES FARTHER TO
THE SOUTHEAST. WHILE TORNADO THREAT LOOKS TO BE LOWER THAN WHAT THE
MODELS SHOWED YESTERDAY...IT IS CERTAINLY NOT ZERO IN FAR SOUTHEAST
NEBRASKA.
AM EXPECTING CONTINUED DEVELOPMENT OF SCATTERED THUNDERSTORMS
THROUGH THE AFTERNOON AS BROAD ASCENT OVERSPREADS THE AREA AHEAD OF
UPPER LOW. A COUPLE OF CLUSTERS OR LINES COULD FORM FROM TIME TO
TIME IN OUR WEST OR SOUTHWEST CWA AND MOVE NORTHEAST. BUT THE BEST
SEVERE THREAT WILL COME LATER IN THE DAY...SAY AFTER 4 PM...IN
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WHERE WARMING/MOISTENING WILL
OCCUR OUTSIDE OF CONTAMINATED AIR TO THE WEST WHERE INTERMITTENT
STORMS/CLOUDS WILL TEND TO DAMPEN THREAT OF SURFACE-BASED STORMS.
DERGAN
PREV DISCUSSION... /ISSUED 641 AM CDT SUN MAY 19 2013/
DISCUSSION...
HAVE UPDATED FORECAST FOR TEMPERATURE TRENDS AS TEMPS DIP INTO THE
LOWER 60S...AS WELL AS FOR PRECIP TRENDS. CWA IS CURRENTLY
DRY...WITH SHOWERS JUST SOUTHEAST AND JUST NORTHWEST...AND BOTH OF
THOSE AREAS WEAKENING AS SHOWERS APPROACH. THINK CWA WILL LARGELY
BE DRY THROUGH THE MORNING...THOUGH DID HEDGE WITH SLIGHT CHANCE
POPS IN THE LATE MORNING IN CASE SOME SHOWERS/ISOLATED THUNDER
SNEAK INTO THE AREA. SHOULD SEE QUICK TEMPERATURE RECOVERY THIS
MORNING WITH RELATIVELY LOW CLOUD COVER...AND WINDS WILL RETURN
OUT OF THE SOUTHEAST AS OUTFLOW FROM OVERNIGHT CONVECTION MIXES
OUT. STILL POTENTIAL FOR THUNDERSTORMS - INCLUDING SEVERE - THIS
AFTERNOON AND EVENING...PARTICULARLY IN THE SOUTHEASTERN CWA WHERE
SHEAR PROFILES ARE BETTER.
MAYES
AVIATION...
12Z TAFS FOR KOMA...KLNK...AND KOFK.
COMPLEX FORECAST AGAIN FOR THE NEXT 24 HRS REGARDING TIMING AND
LOCATION OF THUNDERSTORMS AND RAIN. MORNING SHOULD BE CLEAR OF
ACTIVITY...WITH SHOWERS AND THUNDERSTORMS INCREASING IN THE
AFTERNOON. FOR NOW...HAVE KEPT A FAIRLY GENERIC MENTION OVER A
BROAD TIME SWATH...BUT THIS IS ONE OF THOSE CASES WHERE STORMS MAY
INDEED LINGER IN VICINITY OF AIRPORTS FOR SEVERAL HOURS. TIMING OF
STORMS MAY NEED TO BE ADJUSTED THOUGH...AS SITUATION BECOMES MORE
CLEAR. STORMS WOULD HAVE POTENTIAL TO REDUCE VIS AND MAYBE
CEILINGS TO MVFR BRIEFLY...WITH GUSTY WINDS ALSO POSSIBLE.
ACTIVITY SHOULD CLEAR THROUGH DURING THE EVENING...WITH LINGERING
SHOWERS THROUGH THE NIGHT THAT ARE LESS LIKELY TO CAUSE CATEGORY
RESTRICTIONS.
MAYES
PREV DISCUSSION... /ISSUED 408 AM CDT SUN MAY 19 2013/
DISCUSSION...(TODAY THROUGH NEXT SUNDAY)
ISSUED AT 408 AM CDT SUN MAY 19 2013
THE MAIN FORECAST CONCERN DURING THIS PERIOD IS SEVERE WEATHER
POTENTIAL THIS AFTERNOON AND TONIGHT.
TO START OUT THE DAY EXPECT GENERALLY DRIER WEATHER ONCE LAST
NIGHTS CONVECTION LEAVES THE AREA IN THE NEXT COUPLE HOURS. THIS
DRY WEATHER SHOULD BE SHORT LIVED ONCE THE MAIN UPPER LOW SHIFTS
EAST INTO NEBRASKA THIS EVENING ALLOWING A SURFACE FRONT TO SHIFT
ACROSS THE AREA. SEVERE WEATHER PARAMETERS INDICATE BEST POTENTIAL
FOR SEVERE WEATHER IS ACROSS FAR SOUTHEASTERN NEBRASKA WHERE A
MODERATE RISK FOR SEVERE WEATHER EXISTS. HERE...DEEP LAYER SHEAR
VALUES PUSH 50 KNOTS ALONG WITH PLENTY OF SURFACE BASED
INSTABILITY. THE MAIN SEVERE WEATHER THREAT IN THIS AREA IS LARGE
HAIL...DAMAGING WINDS AND POSSIBLY A FEW TORNADOES. ELSEWHERE THE
SEVERE WEATHER THREAT IS LOWER...BUT STILL REMAINS. AWAY FROM THE
MODERATE RISK AREA HAIL AND WIND ARE THE PRIMARY SEVERE WEATHER
THREATS.
FOR MONDAY AND TUESDAY THE UPPER LOW LINGERS ACROSS THE AREA. WITH
DEEPER MOISTURE PROGGED OVER THE NORTHERN HALF OF THE CWA...HAVE
FAVORED HIGHER PRECIPITATION CHANCES THERE. ALSO TEMPERATURES WILL
BE COOLER WITH HIGHS IN THE 70S ON MONDAY AND GENERALLY IN THE 60S
ON TUESDAY. THEREAFTER THE COOLER WEATHER LINGERS UNTIL THE UPPER
LOW FINALLY DEPARTS ON THURSDAY AND HIGH PRESSURE IS ESTABLISHED
BY THE END OF THE WEEK.
DJP
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KOAX 191632
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1132 AM CDT SUN MAY 19 2013
.UPDATE...
A COUPLE OF VORTICITY MAXIMA WERE NOTED ON SATELLITE AND RADAR LATE
THIS MORNING...ONE LIFTING NORTH INTO NORTHWEST IOWA...AND ANOTHER
MOVING NORTHEAST INTO NORTH CENTRAL NEBRASKA. EASTERN VORT WAS
TAKING SHOWERS AND ISOLATED THUNDERSTORMS WITH IT...SO EXPECT A FEW
MORE HOURS OF PESKY SHOWERS IN WEST CENTRAL IOWA. TO THE
WEST...SHOWERS AND THUNDERSTORMS WERE BEGINNING TO FIRE ALONG A
SPOKE OF VORTICITY AROUND WESTERN CENTER...BUBBLING UP IN OUR FAR
WESTERN CWA. NOT EXPECTING ANYTHING MAJOR WITH THESE STORMS AS
INSTABILITY HAS REMAINED IN CHECK DUE TO LINGERING MORNING RAINS.
HOWEVER INSTABILITY IS EXPECTED TO INCREASE MARKEDLY ACROSS A GOOD
PART OF EASTERN NEBRASKA AND WESTERN IOWA THIS AFTERNOON AS
SOUTHERLY FLOW DRAWS MOISTENING LOW LEVEL AIR NORTH AND MID LEVEL
TEMPERATURES COOL WITH APPROACH OF UPPER TROUGH/LOW. MID LEVEL LAPSE
RATES GREATER THAN 8 C/KM ARE EXPECTED. RAP CAPE FORECASTS SUGGEST
SURFACE BASED VALUES WILL APPROACH 2500 J/KG OVER THE SOUTHERN HALF
OF OUR CWA WHERE SUNSHINE IS MOST LIKELY AND SOUTH OF WARM FRONTAL
BOUNDARY SLOWLY LIFTING TOWARD OR JUST NORTH OF INTERSTATE 80 BY MID
AFTERNOON. SHEAR PROFILES WILL BE WEAKENING WITH TIME WITH APPROACH
OF UPPER/SURFACE LOWS...BUT 40 TO 50KT OF 0-6KM BULK SHEAR IS STILL
EXPECTED ACROSS SOUTHEAST NEBRASKA THROUGH 00Z..COINCIDENT WITH
RELATIVE MAXIMUM IN CAPE FIELD. AND 0-1KM STORM-RELATIVE HELICITY
APPROACHES 120. SO AT LEAST MODERATE INSTABILITY WILL BRING A HAIL
THREAT TO MUCH OF THE SOUTHEAST HALF OF THE CWA...WHILE SHEAR
PROFILES ARE MORE FAVORABLE TO A VARIETY OF SEVERE MODES FARTHER TO
THE SOUTHEAST. WHILE TORNADO THREAT LOOKS TO BE LOWER THAN WHAT THE
MODELS SHOWED YESTERDAY...IT IS CERTAINLY NOT ZERO IN FAR SOUTHEAST
NEBRASKA.
AM EXPECTING CONTINUED DEVELOPMENT OF SCATTERED THUNDERSTORMS
THROUGH THE AFTERNOON AS BROAD ASCENT OVERSPREADS THE AREA AHEAD OF
UPPER LOW. A COUPLE OF CLUSTERS OR LINES COULD FORM FROM TIME TO
TIME IN OUR WEST OR SOUTHWEST CWA AND MOVE NORTHEAST. BUT THE BEST
SEVERE THREAT WILL COME LATER IN THE DAY...SAY AFTER 4 PM...IN
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA WHERE WARMING/MOISTENING WILL
OCCUR OUTSIDE OF CONTAMINATED AIR TO THE WEST WHERE INTERMITTENT
STORMS/CLOUDS WILL TEND TO DAMPEN THREAT OF SURFACE-BASED STORMS.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 641 AM CDT SUN MAY 19 2013/
DISCUSSION...
HAVE UPDATED FORECAST FOR TEMPERATURE TRENDS AS TEMPS DIP INTO THE
LOWER 60S...AS WELL AS FOR PRECIP TRENDS. CWA IS CURRENTLY
DRY...WITH SHOWERS JUST SOUTHEAST AND JUST NORTHWEST...AND BOTH OF
THOSE AREAS WEAKENING AS SHOWERS APPROACH. THINK CWA WILL LARGELY
BE DRY THROUGH THE MORNING...THOUGH DID HEDGE WITH SLIGHT CHANCE
POPS IN THE LATE MORNING IN CASE SOME SHOWERS/ISOLATED THUNDER
SNEAK INTO THE AREA. SHOULD SEE QUICK TEMPERATURE RECOVERY THIS
MORNING WITH RELATIVELY LOW CLOUD COVER...AND WINDS WILL RETURN
OUT OF THE SOUTHEAST AS OUTFLOW FROM OVERNIGHT CONVECTION MIXES
OUT. STILL POTENTIAL FOR THUNDERSTORMS - INCLUDING SEVERE - THIS
AFTERNOON AND EVENING...PARTICULARLY IN THE SOUTHEASTERN CWA WHERE
SHEAR PROFILES ARE BETTER.
MAYES
AVIATION...
12Z TAFS FOR KOMA...KLNK...AND KOFK.
COMPLEX FORECAST AGAIN FOR THE NEXT 24 HRS REGARDING TIMING AND
LOCATION OF THUNDERSTORMS AND RAIN. MORNING SHOULD BE CLEAR OF
ACTIVITY...WITH SHOWERS AND THUNDERSTORMS INCREASING IN THE
AFTERNOON. FOR NOW...HAVE KEPT A FAIRLY GENERIC MENTION OVER A
BROAD TIME SWATH...BUT THIS IS ONE OF THOSE CASES WHERE STORMS MAY
INDEED LINGER IN VICINITY OF AIRPORTS FOR SEVERAL HOURS. TIMING OF
STORMS MAY NEED TO BE ADJUSTED THOUGH...AS SITUATION BECOMES MORE
CLEAR. STORMS WOULD HAVE POTENTIAL TO REDUCE VIS AND MAYBE
CEILINGS TO MVFR BRIEFLY...WITH GUSTY WINDS ALSO POSSIBLE.
ACTIVITY SHOULD CLEAR THROUGH DURING THE EVENING...WITH LINGERING
SHOWERS THROUGH THE NIGHT THAT ARE LESS LIKELY TO CAUSE CATEGORY
RESTRICTIONS.
MAYES
PREV DISCUSSION... /ISSUED 408 AM CDT SUN MAY 19 2013/
DISCUSSION...(TODAY THROUGH NEXT SUNDAY)
ISSUED AT 408 AM CDT SUN MAY 19 2013
THE MAIN FORECAST CONCERN DURING THIS PERIOD IS SEVERE WEATHER
POTENTIAL THIS AFTERNOON AND TONIGHT.
TO START OUT THE DAY EXPECT GENERALLY DRIER WEATHER ONCE LAST
NIGHTS CONVECTION LEAVES THE AREA IN THE NEXT COUPLE HOURS. THIS
DRY WEATHER SHOULD BE SHORT LIVED ONCE THE MAIN UPPER LOW SHIFTS
EAST INTO NEBRASKA THIS EVENING ALLOWING A SURFACE FRONT TO SHIFT
ACROSS THE AREA. SEVERE WEATHER PARAMETERS INDICATE BEST POTENTIAL
FOR SEVERE WEATHER IS ACROSS FAR SOUTHEASTERN NEBRASKA WHERE A
MODERATE RISK FOR SEVERE WEATHER EXISTS. HERE...DEEP LAYER SHEAR
VALUES PUSH 50 KNOTS ALONG WITH PLENTY OF SURFACE BASED
INSTABILITY. THE MAIN SEVERE WEATHER THREAT IN THIS AREA IS LARGE
HAIL...DAMAGING WINDS AND POSSIBLY A FEW TORNADOES. ELSEWHERE THE
SEVERE WEATHER THREAT IS LOWER...BUT STILL REMAINS. AWAY FROM THE
MODERATE RISK AREA HAIL AND WIND ARE THE PRIMARY SEVERE WEATHER
THREATS.
FOR MONDAY AND TUESDAY THE UPPER LOW LINGERS ACROSS THE AREA. WITH
DEEPER MOISTURE PROGGED OVER THE NORTHERN HALF OF THE CWA...HAVE
FAVORED HIGHER PRECIPITATION CHANCES THERE. ALSO TEMPERATURES WILL
BE COOLER WITH HIGHS IN THE 70S ON MONDAY AND GENERALLY IN THE 60S
ON TUESDAY. THEREAFTER THE COOLER WEATHER LINGERS UNTIL THE UPPER
LOW FINALLY DEPARTS ON THURSDAY AND HIGH PRESSURE IS ESTABLISHED
BY THE END OF THE WEEK.
DJP
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 191141
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
641 AM CDT SUN MAY 19 2013
.DISCUSSION...
HAVE UPDATED FORECAST FOR TEMPERATURE TRENDS AS TEMPS DIP INTO THE
LOWER 60S...AS WELL AS FOR PRECIP TRENDS. CWA IS CURRENTLY
DRY...WITH SHOWERS JUST SOUTHEAST AND JUST NORTHWEST...AND BOTH OF
THOSE AREAS WEAKENING AS SHOWERS APPROACH. THINK CWA WILL LARGELY
BE DRY THROUGH THE MORNING...THOUGH DID HEDGE WITH SLIGHT CHANCE
POPS IN THE LATE MORNING IN CASE SOME SHOWERS/ISOLATED THUNDER
SNEAK INTO THE AREA. SHOULD SEE QUICK TEMPERATURE RECOVERY THIS
MORNING WITH RELATIVELY LOW CLOUD COVER...AND WINDS WILL RETURN
OUT OF THE SOUTHEAST AS OUTFLOW FROM OVERNIGHT CONVECTION MIXES
OUT. STILL POTENTIAL FOR THUNDERSTORMS - INCLUDING SEVERE - THIS
AFTERNOON AND EVENING...PARTICULARLY IN THE SOUTHEASTERN CWA WHERE
SHEAR PROFILES ARE BETTER.
MAYES
&&
.AVIATION...
12Z TAFS FOR KOMA...KLNK...AND KOFK.
COMPLEX FORECAST AGAIN FOR THE NEXT 24 HRS REGARDING TIMING AND
LOCATION OF THUNDERSTORMS AND RAIN. MORNING SHOULD BE CLEAR OF
ACTIVITY...WITH SHOWERS AND THUNDERSTORMS INCREASING IN THE
AFTERNOON. FOR NOW...HAVE KEPT A FAIRLY GENERIC MENTION OVER A
BROAD TIME SWATH...BUT THIS IS ONE OF THOSE CASES WHERE STORMS MAY
INDEED LINGER IN VICINITY OF AIRPORTS FOR SEVERAL HOURS. TIMING OF
STORMS MAY NEED TO BE ADJUSTED THOUGH...AS SITUATION BECOMES MORE
CLEAR. STORMS WOULD HAVE POTENTIAL TO REDUCE VIS AND MAYBE
CEILINGS TO MVFR BRIEFLY...WITH GUSTY WINDS ALSO POSSIBLE.
ACTIVITY SHOULD CLEAR THROUGH DURING THE EVENING...WITH LINGERING
SHOWERS THROUGH THE NIGHT THAT ARE LESS LIKELY TO CAUSE CATEGORY
RESTRICTIONS.
MAYES
&&
.PREV DISCUSSION... /ISSUED 408 AM CDT SUN MAY 19 2013/
DISCUSSION...(TODAY THROUGH NEXT SUNDAY)
ISSUED AT 408 AM CDT SUN MAY 19 2013
THE MAIN FORECAST CONCERN DURING THIS PERIOD IS SEVERE WEATHER
POTENTIAL THIS AFTERNOON AND TONIGHT.
TO START OUT THE DAY EXPECT GENERALLY DRIER WEATHER ONCE LAST
NIGHTS CONVECTION LEAVES THE AREA IN THE NEXT COUPLE HOURS. THIS
DRY WEATHER SHOULD BE SHORT LIVED ONCE THE MAIN UPPER LOW SHIFTS
EAST INTO NEBRASKA THIS EVENING ALLOWING A SURFACE FRONT TO SHIFT
ACROSS THE AREA. SEVERE WEATHER PARAMETERS INDICATE BEST POTENTIAL
FOR SEVERE WEATHER IS ACROSS FAR SOUTHEASTERN NEBRASKA WHERE A
MODERATE RISK FOR SEVERE WEATHER EXISTS. HERE...DEEP LAYER SHEAR
VALUES PUSH 50 KNOTS ALONG WITH PLENTY OF SURFACE BASED
INSTABILITY. THE MAIN SEVERE WEATHER THREAT IN THIS AREA IS LARGE
HAIL...DAMAGING WINDS AND POSSIBLY A FEW TORNADOES. ELSEWHERE THE
SEVERE WEATHER THREAT IS LOWER...BUT STILL REMAINS. AWAY FROM THE
MODERATE RISK AREA HAIL AND WIND ARE THE PRIMARY SEVERE WEATHER
THREATS.
FOR MONDAY AND TUESDAY THE UPPER LOW LINGERS ACROSS THE AREA. WITH
DEEPER MOISTURE PROGGED OVER THE NORTHERN HALF OF THE CWA...HAVE
FAVORED HIGHER PRECIPITATION CHANCES THERE. ALSO TEMPERATURES WILL
BE COOLER WITH HIGHS IN THE 70S ON MONDAY AND GENERALLY IN THE 60S
ON TUESDAY. THEREAFTER THE COOLER WEATHER LINGERS UNTIL THE UPPER
LOW FINALLY DEPARTS ON THURSDAY AND HIGH PRESSURE IS ESTABLISHED
BY THE END OF THE WEEK.
AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM CDT SUN MAY 19 2013
ALTHOUGH THUNDERSTORM CHANCES LINGER OVER THE REGION THROUGH
SUNDAY AFTERNOON/EVENING...19/06Z FORECAST JUST CARRIED MENTION
THROUGH 10Z WITH INITIAL ROUND. AFTER THAT RESIDUAL MOISTURE COULD
ALLOW LOW CLOUDS WITH IFR/LOWER RANGE MVFR CONDITIONS POSSIBLE
UNTIL DAYTIME HEATING CAN IMPROVE CONDITIONS. HOWEVER...MIXING
FROM CONTINUED SHOWERS/ISOLD TSTMS WOULD IMPACT THAT. ANOTHER
ROUND OF CONVECTION EXPECTED SUNDAY AFTN AND EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
000
FXUS63 KOAX 190908
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
408 AM CDT SUN MAY 19 2013
.DISCUSSION...(TODAY THROUGH NEXT SUNDAY)
ISSUED AT 408 AM CDT SUN MAY 19 2013
THE MAIN FORECAST CONCERN DURING THIS PERIOD IS SEVERE WEATHER
POTENTIAL THIS AFTERNOON AND TONIGHT.
TO START OUT THE DAY EXPECT GENERALLY DRIER WEATHER ONCE LAST
NIGHTS CONVECTION LEAVES THE AREA IN THE NEXT COUPLE HOURS. THIS
DRY WEATHER SHOULD BE SHORT LIVED ONCE THE MAIN UPPER LOW SHIFTS
EAST INTO NEBRASKA THIS EVENING ALLOWING A SURFACE FRONT TO SHIFT
ACROSS THE AREA. SEVERE WEATHER PARAMETERS INDICATE BEST POTENTIAL
FOR SEVERE WEATHER IS ACROSS FAR SOUTHEASTERN NEBRASKA WHERE A
MODERATE RISK FOR SEVERE WEATHER EXISTS. HERE...DEEP LAYER SHEAR
VALUES PUSH 50 KNOTS ALONG WITH PLENTY OF SURFACE BASED
INSTABILITY. THE MAIN SEVERE WEATHER THREAT IN THIS AREA IS LARGE
HAIL...DAMAGING WINDS AND POSSIBLY A FEW TORNADOES. ELSEWHERE THE
SEVERE WEATHER THREAT IS LOWER...BUT STILL REMAINS. AWAY FROM THE
MODERATE RISK AREA HAIL AND WIND ARE THE PRIMARY SEVERE WEATHER
THREATS.
FOR MONDAY AND TUESDAY THE UPPER LOW LINGERS ACROSS THE AREA. WITH
DEEPER MOISTURE PROGGED OVER THE NORTHERN HALF OF THE CWA...HAVE
FAVORED HIGHER PRECIPITATION CHANCES THERE. ALSO TEMPERATURES WILL
BE COOLER WITH HIGHS IN THE 70S ON MONDAY AND GENERALLY IN THE 60S
ON TUESDAY. THEREAFTER THE COOLER WEATHER LINGERS UNTIL THE UPPER
LOW FINALLY DEPARTS ON THURSDAY AND HIGH PRESSURE IS ESTABLISHED
BY THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM CDT SUN MAY 19 2013
ALTHOUGH THUNDERSTORM CHANCES LINGER OVER THE REGION THROUGH
SUNDAY AFTERNOON/EVENING...19/06Z FORECAST JUST CARRIED MENTION
THROUGH 10Z WITH INITIAL ROUND. AFTER THAT RESIDUAL MOISTURE COULD
ALLOW LOW CLOUDS WITH IFR/LOWER RANGE MVFR CONDITIONS POSSIBLE
UNTIL DAYTIME HEATING CAN IMPROVE CONDITIONS. HOWEVER...MIXING
FROM CONTINUED SHOWERS/ISOLD TSTMS WOULD IMPACT THAT. ANOTHER
ROUND OF CONVECTION EXPECTED SUNDAY AFTN AND EVENING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
DISCUSSION...PEARSON
AVIATION...CHERMOK
000
FXUS63 KOAX 182338
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
638 PM CDT SAT MAY 18 2013
.AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK
THUNDERSTORM TIMING/COVERAGE TONIGHT AND AGAIN SUNDAY AFTERNOON
PLUS LOW CLOUD DEVELOPMENT LATE TONIGHT ARE AMONG AVIATION
ISSUES. TAF FORECAST REFLECTED BEST ESTIMATES OF TSTM ACTIVITY
TONIGHT WITH TEMPO GROUPS AND PROB30S WERE THEN CARRIED AT SITES
SUNDAY AFTERNOON. HOWEVER...CONVECTION COULD LINGER ACROSS THE
AREA SUNDAY MORNING AND TRENDS WILL NEED MONITORING. WOULD SUSPECT
WITH UPPER 60S SFC DWPTS FM SERN NEBR INTO KS THAT LOW CLOUD
DEVELOPMENT QUITE POSSIBLE BY SUNDAY MORNING OVER MUCH OF THE
REGION AND THIS WAS CARRIED IN 00Z FORECASTS. MIXING DUE TO
CONVECTION COULD ALTER THE TIMING/COVERAGE...HOWEVER.
CHERMOK
&&
.PREV DISCUSSION... /ISSUED 338 PM CDT SAT MAY 18 2013/
DISCUSSION...
SEVERE THUNDERSTORM CHANCES THROUGH SUNDAY EVENING ARE THE PRIMARY
FORECAST CONCERNS.
WESTERN UPPER WAVE WAS DRIFTING TOWARD THE ROCKIES THIS AFTERNOON.
STRONG SOUTHWEST FLOW AHEAD OF THIS SYSTEM WAS OVERSPREADING HIGH
PLAINS REGION...INDUCING CYCLOGENESIS IN SOUTHWEST NEBRASKA AND
WESTERN KANSAS WHERE SKIES HAD CLEARED. STRONG INSTABILITY HAS
DEVELOPED AHEAD OF THIS LOW WITH MOST UNSTABLE CAPES RUNNING OVER
4000 J/KG FROM SOUTHWEST NEBRASKA THROUGH CENTRAL KANSAS...JUST
AHEAD OF DRY LINE. SPC HAS JUST ISSUED A TORNADO WATCH FOR THESE
AREAS COVERING WESTERN NEBRASKA THROUGH MUCH OF WESTERN INTO CENTRAL
KANSAS. FOR OUR AREA...BROKEN MID LEVEL CLOUD COVER HAS DAMPENED
INSOLATION THIS AFTERNOON...HOLDING TEMPERATURES IN THE LOWER 80S.
OVERNIGHT EXPECT CONVECTION FROM WESTERN AREAS TO ROLL EAST AND
NORTHEAST ACROSS CENTRAL INTO EASTERN NEBRASKA...AND EVENTUALLY
SOUTHWEST IOWA...AS LOW LEVEL JET PUSHING 40KT CONTINUES TO PUMP
HIGHER THETA-E AIR INTO OUR REGION. HOWEVER...EXACT EVOLUTION OF
WESTERN CONVECTION WILL HAVE TO BE WATCHED AS SEVERAL SHORT RANGE
MODELS SUGGEST A SPLIT IN ACTIVITY WITH ONE AREA LIFTING INTO
NORTHEAST NEBRASKA AND ANOTHER SETTING UP OVER NORTHERN KANSAS. BUT
OTHERS SUGGEST A MCS WILL ROLL RIGHT INTO EASTERN NEBRASKA LATE THIS
EVENING. AT ANY RATE...PRECIP CHANCES WILL BE ON THE INCREASE FROM
LATE EVENING ON...WITH THE THREAT OF SEVERE WEATHER STILL THERE.
MODELS SUGGEST ELEVATED CAPE VALUES WILL STILL BE TOPPING 2000 J/KG
AS STORMS MOVE IN...SO HAIL IS CERTAINLY A THREAT. IF STORMS DO NOT
BECOME ELEVATED WITH TIME AS EXPECTED...THEN WINDS COULD ALSO BE A
PROBLEM...ESPECIALLY DURING THE LATE EVENING. MOST LIKELY AREAS FOR
SEVERE WOULD BE NEAR THE KANSAS BORDER WHERE A PLURALITY OF SHORT
RANGE ENSEMBLE MEMBERS PAINT A SWATH OF STRONG STORMS...OR OVER
NORTHEAST NEBRASKA WHERE SEVERAL MODELS POINT TO MCS TRACK.
ACTIVITY SHOULD CONTINUE WELL PAST MIDNIGHT BEFORE MOVING EAST OF
OUR AREA SUNDAY MORNING. LOOKS LIKE WE COULD HAVE A SUBSTANTIAL LULL
IN ACTIVITY DURING THE MORNING BEFORE ROUND TWO BEGINS SUNDAY
AFTERNOON. UPPER TROUGH WILL PUSH FARTHER INTO THE PLAINS...PUSHING
SURFACE TROUGH/LOW INTO EASTERN NEBRASKA AND EASTERN KANSAS.
SUBSTANTIAL INSTABILITY WILL EXIST AHEAD OF THIS BOUNDARY DURING THE
AFTERNOON...BUT SHEAR PROFILES WILL BE DECREASING WITH TIME AS WE
HEAD LATER IN THE AFTERNOON OWING TO SLACKENING GRADIENT CLOSER TO
SURFACE/UPPER TROUGHS. VERY STEEP LOW AND MID LEVEL LAPSE RATES ON
THE ORDER OF 8 C/KM WILL EXIST OVER MUCH OF OUR AREA...AND FORECAST
SOUNDINGS SHOW INHIBITION GOING AWAY BY MID TO LATE AFTERNOON. MIXED
LAYER CAPE VALUES OVER 2500 J/KG ARE PROGGED OVER MUCH OF OUR
AREA...WITH 0-6KM SHEAR AROUND 40KT. SO SUPERCELLS LOOK LIKELY WITH
LARGE HAIL AND DAMAGING WINDS CERTAINLY...BUT TORNADO POTENTIAL IS
STILL IN QUESTION. LOW LEVEL SHEAR IS MOST PRONOUNCED IN OUR FAR
SOUTHEAST CWA...BUT ANY WARM FRONTAL BOUNDARY THAT ROTATES NORTH
AROUND SURFACE LOW WILL BE A CANDIDATE TO FOCUS TORNADO THREAT AS
WELL.
SEVERE THREAT WILL LAST THROUGH THE EVENING BEFORE SURFACE BOUNDARY
SHIFTS EAST AND FOCUSES STORMS MORE IN IOWA AND MISSOURI. HOWEVER
UPPER LOW CUTTING OFF JUST NORTH OF NEBRASKA AND LINGERING MID
LEVEL INSTABILITY WILL BRING CONTINUED THUNDER CHANCE INTO MONDAY.
THAT LOW WILL REMAIN IN OUR AREA THROUGH AT LEAST MID
WEEK...BRINGING OFF AND ON SHOWERS AND ISOLATED THUNDERSTORMS ALONG
WITH COOLER TEMPERATURES. IT LOOKS LIKE A WARMING TREND IS IN STORE
FOR LATE IN THE WEEK AS UPPER LOW FINALLY MOVES EAST AND HEIGHTS
BEGIN TO RISE.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 182038
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
338 PM CDT SAT MAY 18 2013
.DISCUSSION...
SEVERE THUNDERSTORM CHANCES THROUGH SUNDAY EVENING ARE THE PRIMARY
FORECAST CONCERNS.
WESTERN UPPER WAVE WAS DRIFTING TOWARD THE ROCKIES THIS AFTERNOON.
STRONG SOUTHWEST FLOW AHEAD OF THIS SYSTEM WAS OVERSPREADING HIGH
PLAINS REGION...INDUCING CYCLOGENESIS IN SOUTHWEST NEBRASKA AND
WESTERN KANSAS WHERE SKIES HAD CLEARED. STRONG INSTABILITY HAS
DEVELOPED AHEAD OF THIS LOW WITH MOST UNSTABLE CAPES RUNNING OVER
4000 J/KG FROM SOUTHWEST NEBRASKA THROUGH CENTRAL KANSAS...JUST
AHEAD OF DRY LINE. SPC HAS JUST ISSUED A TORNADO WATCH FOR THESE
AREAS COVERING WESTERN NEBRASKA THROUGH MUCH OF WESTERN INTO CENTRAL
KANSAS. FOR OUR AREA...BROKEN MID LEVEL CLOUD COVER HAS DAMPENED
INSOLATION THIS AFTERNOON...HOLDING TEMPERATURES IN THE LOWER 80S.
OVERNIGHT EXPECT CONVECTION FROM WESTERN AREAS TO ROLL EAST AND
NORTHEAST ACROSS CENTRAL INTO EASTERN NEBRASKA...AND EVENTUALLY
SOUTHWEST IOWA...AS LOW LEVEL JET PUSHING 40KT CONTINUES TO PUMP
HIGHER THETA-E AIR INTO OUR REGION. HOWEVER...EXACT EVOLUTION OF
WESTERN CONVECTION WILL HAVE TO BE WATCHED AS SEVERAL SHORT RANGE
MODELS SUGGEST A SPLIT IN ACTIVITY WITH ONE AREA LIFTING INTO
NORTHEAST NEBRASKA AND ANOTHER SETTING UP OVER NORTHERN KANSAS. BUT
OTHERS SUGGEST A MCS WILL ROLL RIGHT INTO EASTERN NEBRASKA LATE THIS
EVENING. AT ANY RATE...PRECIP CHANCES WILL BE ON THE INCREASE FROM
LATE EVENING ON...WITH THE THREAT OF SEVERE WEATHER STILL THERE.
MODELS SUGGEST ELEVATED CAPE VALUES WILL STILL BE TOPPING 2000 J/KG
AS STORMS MOVE IN...SO HAIL IS CERTAINLY A THREAT. IF STORMS DO NOT
BECOME ELEVATED WITH TIME AS EXPECTED...THEN WINDS COULD ALSO BE A
PROBLEM...ESPECIALLY DURING THE LATE EVENING. MOST LIKELY AREAS FOR
SEVERE WOULD BE NEAR THE KANSAS BORDER WHERE A PLURALITY OF SHORT
RANGE ENSEMBLE MEMBERS PAINT A SWATH OF STRONG STORMS...OR OVER
NORTHEAST NEBRASKA WHERE SEVERAL MODELS POINT TO MCS TRACK.
ACTIVITY SHOULD CONTINUE WELL PAST MIDNIGHT BEFORE MOVING EAST OF
OUR AREA SUNDAY MORNING. LOOKS LIKE WE COULD HAVE A SUBSTANTIAL LULL
IN ACTIVITY DURING THE MORNING BEFORE ROUND TWO BEGINS SUNDAY
AFTERNOON. UPPER TROUGH WILL PUSH FARTHER INTO THE PLAINS...PUSHING
SURFACE TROUGH/LOW INTO EASTERN NEBRASKA AND EASTERN KANSAS.
SUBSTANTIAL INSTABILITY WILL EXIST AHEAD OF THIS BOUNDARY DURING THE
AFTERNOON...BUT SHEAR PROFILES WILL BE DECREASING WITH TIME AS WE
HEAD LATER IN THE AFTERNOON OWING TO SLACKENING GRADIENT CLOSER TO
SURFACE/UPPER TROUGHS. VERY STEEP LOW AND MID LEVEL LAPSE RATES ON
THE ORDER OF 8 C/KM WILL EXIST OVER MUCH OF OUR AREA...AND FORECAST
SOUNDINGS SHOW INHIBITION GOING AWAY BY MID TO LATE AFTERNOON. MIXED
LAYER CAPE VALUES OVER 2500 J/KG ARE PROGGED OVER MUCH OF OUR
AREA...WITH 0-6KM SHEAR AROUND 40KT. SO SUPERCELLS LOOK LIKELY WITH
LARGE HAIL AND DAMAGING WINDS CERTAINLY...BUT TORNADO POTENTIAL IS
STILL IN QUESTION. LOW LEVEL SHEAR IS MOST PRONOUNCED IN OUR FAR
SOUTHEAST CWA...BUT ANY WARM FRONTAL BOUNDARY THAT ROTATES NORTH
AROUND SURFACE LOW WILL BE A CANDIDATE TO FOCUS TORNADO THREAT AS
WELL.
SEVERE THREAT WILL LAST THROUGH THE EVENING BEFORE SURFACE BOUNDARY
SHIFTS EAST AND FOCUSES STORMS MORE IN IOWA AND MISSOURI. HOWEVER
UPPER LOW CUTTING OFF JUST NORTH OF NEBRASKA AND LINGERING MID
LEVEL INSTABILITY WILL BRING CONTINUED THUNDER CHANCE INTO MONDAY.
THAT LOW WILL REMAIN IN OUR AREA THROUGH AT LEAST MID
WEEK...BRINGING OFF AND ON SHOWERS AND ISOLATED THUNDERSTORMS ALONG
WITH COOLER TEMPERATURES. IT LOOKS LIKE A WARMING TREND IS IN STORE
FOR LATE IN THE WEEK AS UPPER LOW FINALLY MOVES EAST AND HEIGHTS
BEGIN TO RISE.
DERGAN
&&
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
A FEW ELEVATED SHOWERS AROUND TODAY WITH THUNDERSTORMS INCREASING
IN PROBABILITY TONIGHT. VFR CIGS MOSTLY FL035-050...HOWEVER DID
MENTION MVFR CIGS AND VSBYS WITH PROB30 GROUPS AFTER 03Z.
SOUTHEAST SURFACE WINDS MOSTLY 10 TO 20KTS THIS AFTERNOON AND 8 TO
15KTS AFTER 01Z. LLWS MAY NEED TO BE ADDED LATER TONIGHT. SHORT
TERM GUIDANCE NOT CONSISTENT ON HOW THIS WILL EVOLVE.
EXTENDED PERIOD OF MID AND UPPER LEVEL LIFT AND WARM AIR ADVECTION
AS A STORM SYSTEM MOVING INTO THE ROCKIES PROGRESSES INTO THE
PLAINS SUNDAY.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
000
FXUS63 KOAX 181850
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
150 PM CDT SAT MAY 18 2013
.UPDATE...
MORNING UPDATE TO ADD SOME SHOWERS AND ISOLATED THUNDERSTORMS IN
NORTHEAST NEBRASKA THIS AFTERNOON AND EARLY AFTERNOON UPDATE AS
THESE MAY GET INTO THE OTHER WESTERN PARTS OF THE CWA DURING THE
AFTERNOON. LOWERED HIGHS AND ADJUSTED THE CLOUDS.
&&
DEEPER MOISTURE AND CLOUDS HAVE INCREASED ACROSS THE FORECAST AREA
AND THIS SHOULD HOLD BACK HIGH TEMPERATURES SOMEWHAT WITH MOST
LOCATIONS TOPPING OUT IN THE LOWER TO MID 80S. A FEW ELEVATED
SHOWERS DEVELOPED AROUND ALBION AND NORFOLK...AND ANOTHER AREA IS
LIFTING NORTH THROUGH NORTH CENTRAL KANSAS INTO CENTRAL NEBRASKA.
DEEP MOISTURE WITH DEWPOINTS IN THE 70S WERE NOTED FROM KANSAS
INTO OKLAHOMA...AND H85 MOISTURE WAS POOLED FROM SOUTHWEST NEB
INTO NORTH CENTRAL KANSAS TO SOUTHEAST KANSAS. THE DRYLINE WAS IN
FAR SOUTHWEST KANSAS AND THE TEXAS PANHANDLE. AS HEATING
CONTINUES ALONG WITH LARGE SCALE LIFT AND A STRENGTHENING LOW
LEVEL JET...LOOK FOR CONVECTION TO INCREASE ACROSS OKLAHOMA AND
KANSAS INTO WESTERN AND CENTRAL NEBRASKA...SPREADING INTO
NORTHEAST NEBRASKA AND THE WESTERN PARTS OF THE FORECAST AREA LATE
THIS AFTERNOON/THIS EVENING AND THEN THE REST OF EASTERN NEBRASKA
AND WESTERN IOWA LATER THIS EVENING AND OVERNIGHT.
&&
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
A FEW ELEVATED SHOWERS AROUND TODAY WITH THUNDERSTORMS INCREASING
IN PROBABILITY TONIGHT. VFR CIGS MOSTLY FL035-050...HOWEVER DID
MENTION MVFR CIGS AND VSBYS WITH PROB30 GROUPS AFTER 03Z.
SOUTHEAST SURFACE WINDS MOSTLY 10 TO 20KTS THIS AFTERNOON AND 8 TO
15KTS AFTER 01Z. LLWS MAY NEED TO BE ADDED LATER TONIGHT. SHORT
TERM GUIDANCE NOT CONSISTENT ON HOW THIS WILL EVOLVE.
EXTENDED PERIOD OF MID AND UPPER LEVEL LIFT AND WARM AIR ADVECTION
AS A STORM SYSTEM MOVING INTO THE ROCKIES PROGRESSES INTO THE
PLAINS SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 339 AM CDT SAT MAY 18 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT.
THE FOCUS FOR THIS PORTION OF THE FORECAST IS SEVERE WEATHER
POTENTIAL TONIGHT AND MORE SO INTO SUNDAY AND SUNDAY NIGHT.
TODAY AND TONIGHT...THIS PERIOD BEGINS WITH UPPER LEVEL RIDGING
IN PLACE. A SUBSIDENCE INVERSION IN PLACE FROM THIS RIDGE WILL
ACT TO SUPRESS CONVECTION FOR MUCH OF THE DAY. THE TRIGGER FOR
ANY CONVECTION WILL BE A SHORTWAVE DIGGING INTO THE BACKSIDE OF
THE RIDGE THIS EVENING INTO TONIGHT. GIVEN THE LACK OF SIGNIFICANT
FORCING AND ENOUGH HEATING (CONVECTIVE TEMP IS AROUND 91 F) ITS
QUITE LIKELY THE ATMOSPHERE WILL REMAIN CAPPED INTO THE EARLY
EVENING HOURS.
THE BETTER OPPORTUNITY FOR WIDESPREAD CONVECTION IS ACROSS
PORTIONS OF WESTERN NEBRASKA/KANSAS AND OKLAHOMA WHERE DRY LINE
INFLUENCES AND STRONG DAY TIME HEATING WILL ACT TO ERODE ANY
EXISTING CAP. THIS WILL BE THE ACTIVITY WE END UP SEEING TONIGHT.
DECIDED TO MAINTAIN GOING FORECAST AND KEEP EASTERN NEBRASKA AND
SOUTHWEST IOWA DRY THROUGH THE DAY...THEN STEADILY PUSH
THUNDERSTORMS CHANCES EAST THROUGH THE EVENING AND OVERNIGHT
HOURS. THE MAIN SEVERE WEATHER THREATS WILL BE HAIL AND WIND AS
OUTLINED BY THE SLIGHT RISK AREA FROM THE STORM PREDICTION CENTER.
SUNDAY THROUGH MONDAY NIGHT...ONCE AGAIN OUR AREA IS OUTLINED IN
THE SLIGHT RISK AREA. THIS PERIOD BRINGS WITH A MUCH BETTER
OPPORTUNITY FOR SEVERE WEATHER. THE MAIN FOCUS IS A NEGATIVELY
TILTED UPPER LEVEL TROUGH MOVING EAST THROUGH THE REGION. UNLIKE
TODAY AND TONIGHT THERE ISN`T A CAPPING INVERSION TO OVERCOME AND
CONVECTION WILL LIKELY INITIATE EARLY IN THE AFTERNOON ON SUNDAY.
MODIFIED FORECAST SOUNDINGS INDICATE MODEST INSTABILITY AVAILABLE
AND DEEP LAYER SHEAR AROUND 35 KNOTS. AS THE UPPER LEVEL TROUGH
AND ITS SURFACE REFLECTION TRANSLATE THROUGH THE AREA...STRONG
THUNDERSTORMS AND EVEN SUPERCELLS ARE EXPECTED TO FORM. THE
SPECIFIC SEVERE WEATHER THREATS ARE LARGE HAIL...POSSIBLY GREATER
THAN 2 INCHES...STRONG WINDS AND EVEN A FEW TORNADOES CAN`T BE
RULED OUT.
UNSETTLED WEATHER WILL CONTINUE THROUGH MONDAY NIGHT AS THE UPPER
LEVEL TROUGH TRANSFORMS INTO A CLOSED LOW AND SLOWLY MEANDERS NORTH
AND EAST. THIS WARRANTS A CONTINUED MENTION OF SHOWERS AND
THUNDERSTORMS AS WELL AS COOLER TEMPERATURES FOR MONDAY.
DP
LONG TERM...TUESDAY THROUGH SATURDAY.
CLOSED UPPER LOW LINGERS OVER THE AREA AT THE BEGINNING OF THE
PERIOD FOR A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS BEFORE
MOVING EAST OF THE AREA ON THURSDAY. SHORT WAVE RIDGE THEN DEVELOPS
THURSDAY NIGHT INTO FRIDAY AS UPPER SYSTEM DIGS OVER THE WESTERN
CONUS WITH INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY
NIGHT INTO SATURDAY AS UPPER ENERGY EJECTS OUT OF THE WESTERN
TROUGH. TEMPERATURES LOOK TO REMAIN SEASONAL THROUGH THE PERIOD.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
| 
