FXUS63 KOAX 140229
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
929 PM CDT MON JUN 13 2011
.DISCUSSION...
00Z SUBJECTIVE UPPER AIR ANALYSIS REVEALED THAT WE MAY BE IN
BETWEEN SYSTEMS TONIGHT...WITH CONVECTION FIRING TO BOTH OUR EAST
AND WEST. CONVECTION ACROSS SOUTHERN IOWA AND NORTHERN MISSOURI
WAS FIRING NORTH OF THE H85 FRONTAL BOUNDARY...ALONG THE NOSE OF
AN INCREASING LOW LEVEL JET. IT WAS TRYING TO BUILD TO THE
WEST...BUT WAS ALSO ENCOUNTERING A VERY HEALTHY CAP AS NOTED BY 11
DEGREE H70 TEMPS AT KOAX...AND 13 AT KTOP. LATEST SWOMCD PRODUCT
HIGHLIGHTS THIS AREA...AND IT WILL CONTINUE TO BE MONITORED.
MEANWHILE...A VERY SUBTLE WAVE EJECTING OUT OF THE MEAN WESTERN
TROUGH WAS KICKING OFF NUMEROUS THUNDERSTORMS ACROSS WESTERN
NEBRASKA...AND THIS COULD MOVE INTO NORTHEAST NEBRASKA LATER
TONIGHT AS WELL...ALTHOUGH IT WILL PROBABLY TAKE SEVERAL HOURS TO
DO SO. ADJUSTED POPS A BIT OVERNIGHT BASED ON CURRENT TRENDS AND
INCREASED CLOUD COVER WITH GENERALLY OVERCAST CONDITIONS.
&&
.HYDROLOGY...
PLAN ON CONVERTING THE FLASH FLOOD WARNING BECAUES OF THE LEVEE
BREACH SOUTHWEST OF HAMBURG TO A FLOOD WARNING LATER THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT MON JUN 13 2011/
SHORT TERM...TONIGHT.
QUESTION STILL REMAINS IF AND WHEN CONVECTION WILL AFFECT THE FA.
OUTFLOW BOUNDARY HAS STALLED OVER NORTHEAST KS AND INTO NW MO AS OF
20Z...AND THIS WILL LIKELY REMAIN STATIONARY THROUGH THE REST OF THE
EVENING. ATMOSPHERE ALONG THE BOUNDARY HAS BECOME STRONGLY TO
EXTREMELY UNSTABLE THIS AFTERNOON WITH 3-4 J/KG OF MLCAPE.
CONVECTIVE INHIBITION CONTINUES TO BE THE MAIN CONCERN FOR CI OVER
THE AREA. MORNING UPPER AIR ANALYSIS INDICATED A STOUT EML JUST OFF
TO THE WEST OF THE AREA...AND THIS WAS EXPECTED TO SHIFT EWD INTO
SOUTHERN NEB/SW IA. LATEST OBJECTIVE ANALYSIS INDICATES THE CAP IS
WEAKENING...BUT STILL PRESENT OVER THIS AREA. ALTHOUGH THERE IS SOME
POTENTIAL FOR AN ISO STORM ALONG THE BOUNDARY...CURRENT FEELING THAT
THE BOUNDARY LAYER WILL REMAINED CAPPED TO SURFACED-BASED CONVECTION
IN OUR FA. WILL MAINTAIN A 15 POP NEAR THE BORDER JUST IN CASE. THE
OTHER AREA IS OVER THE FAR NORTHWEST CWA WHERE A WEAK COLD FRONT IS
APPROACHING. THE ATMOSPHERE OVER NE NEB HAS BEEN WORKED OVER AND HAS
YET TO RECOVER. THUS STORMS TO THE NORTHWEST MAY HAVE TROUBLE MOVING
INTO NE NEB THIS EVENING...AND WILL MAINTAIN A SCHC POP FOR THIS.
THE MOST LIKELY SCENARIO FOR CONVECTION WILL BE AFTER 03Z OVER THE
EASTERN CWA AS THE DIURNAL PLAINS NOCTURNAL LOW LEVEL JET INCREASES
AND IMPINGES ON THE 850 MB BOUNDARY OVER SOUTHWEST IOWA. CONVECTION
SHOULD DEVELOP IN AN ELEVATED FASHION...WITH A MCS POSSIBLE A LITTLE
FARTHER EAST INTO IOWA. GIVEN THE CAPE...THERE IS SOME HAIL THREAT
WITH INITIAL DEVELOPMENT. FINALLY...ONCE AGAIN THERE IS SOME THREAT
OF STORMS DEVELOPING OFF THE HIGH PLAINS MAKING IT INTO OUR FA
TOWARD DAWN...AND WILL MAINTAIN SOME SCHC POP IN THE WEST LATE FOR
THIS.
LONG TERM...TUESDAY THROUGH MONDAY.
LITTLE CHANGE TO OVERALL FORECAST TRENDS WITH MODELS MAINTAINING
FAMILIAR CYCLICAL PATTERN THROUGH THE PERIOD. PRECIP TIMING AND
EXTENT REMAIN PRIMARY CHALLENGE IN THE FORECAST.
NEXT MAJOR UPPER WAVE MOVES INTO THE PLAINS REGION ON TUESDAY WITH
BEST CHANCE FOR MORE SIGNIFICANT STORMS EXPECTED DURING THE
AFTERNOON AND EVENING AS SURFACE WAVE OVER KANSAS LIFTS NORTHEAST
ALONG WARM FRONT POSITIONED JUST SOUTH OF THE FORECAST AREA.
STORMS MAY LINGER INTO THE LATE EVENING AS UPPER WAVE MOVES
THROUGH BUT CHANCES SHOULD CUT OFF QUICKLY AFTER MIDNIGHT.
AREA IS BETWEEN SYSTEMS ON WEDNESDAY SO LOOKS NICE AND DRY WITH
SURFACE HIGH PRESSURE OVER THE REGION AND INCREASING HEIGHTS
ALOFT. NEXT WESTERN TROUGH BEGINS TO IMPACT THE AREA ON THURSDAY WITH
ANOTHER LEE SIDE LOW DEVELOPING OVER EASTERN COLORADO AND WARM
FRONT STRETCHING ACROSS NORTHERN KANSAS. SOME CHANCE OF STORMS
LATE IN THE DAY AND INTO THE EVENING AS WARM ADVECTION RETURNS TO
THE REGION AND LOW LEVEL JET KICKS IN.
THIS SAME GENERAL PATTERN REPEATS IN THE EXTENDED PERIOD WITH
FRONTAL BOUNDARY TO THE SOUTH AND PARADE OF WAVES MOVING OUT OF
THE WESTERN TROUGH AND INTO THE PLAINS REGION WITH A COLD FRONT
AND MAIN TROUGH MOVING THROUGH LATE IN THE PERIOD.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
MVFR CIGS CONTINUE THIS AFTERNOON NORTH OF A WARM FRONT AT LNK/OMA
WITH GENERALLY SKC CONDS AT OFK. THESE CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH THE REST OF THE EVENING AND SPREAD NORTHWARD INTO
OFK LATER. CIGS WILL LIKELY DROP INTO IFR CATEGORY AFTER 04Z AT ALL
TAF SITES WITH MVFR VISBY ALSO LIKELY. SOME POTENTIAL FOR CONVECTION
AT OFK/OMA...BUT TIMING AND INTENSITY ARE STILL VERY MUCH IN DOUBT
AND THUS WILL NOT INCLUDE ATTM. A MIX OF MVFR/IFR CONDITIONS SHOULD
CONTINUE THRU TUES MORNING AT ALL SITES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
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