FXUS63 KOAX 220843
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
341 AM CDT MON AUG 22 2011
...ONGOING THUNDERSTORMS WITH CHANCES THROUGH TONIGHT ARE THE
PRIMARY FORECAST CONCERNS...WITH HIGH HEAT INDEXES TUESDAY ANOTHER
CONCERN...
.DISCUSSION...
A LEAD DISTURBANCE INDICATED ON WATER VAPOR IMAGERY IS MOVING
THROUGH WESTERN NEBRASKA WITH ONLY ISOLATED THUNDERSTORMS ONGOING IN
EASTERN PORTIONS OF NORTH CENTRAL NEBRASKA. A LINE OF NUMEROUS
SHOWERS AND STORMS CURRENTLY FROM CEDAR COUNTY SOUTHEAST THROUGH
DOUGLAS AND SARPY COUNTY INTO SOUTHWEST IOWA HAS RESULTED IN A FEW
SEVERE WARNINGS AND FLASH FLOOD WARNINGS. CURRENT 0-3 KM MUCAPES UP
TO 1500 J/KG WITH 0-6 KM SHEAR OF 25-35 KTS. EXPECTING MORNING
SHOWERS AND THUNDERSTORMS MAINLY ALONG THE MISSOURI VALLEY TO
DIMINISH IN COVERAGE AND DEVELOPMENT BY AROUND NOON WITH SCATTERED
WORDING MENTIONED. NO TRIGGER IS EVIDENT FROM MODELS FOR THE
AFTERNOON AND EVENING. THAT AREA APPEARS TO RESIDE ACROSS FAR
EASTERN SOUTH DAKOTA INTO MINNESOTA AND NORTHERN IOWA. IT APPEARS
THAT ANY OUTFLOWS WHICH MAY EXIST FROM MORNING CONVECTION...MAY BE
THE MAIN FOCUS FOR DEVELOPMENT. MUCAPES SHOW INSTABILITY THIS
AFTERNOON WILL BE MORE THAN ADEQUATE RANGING AS HIGH AS 3500 TO 4500
J/KG...WITH 0-6KM SHEAR LACKING A BIT AT 25-30 KTS. STILL SUFFICIENT
TO SUPPORT A FEW SEVERE STORMS INTO THIS EVENING. POPS TONIGHT IN
THE LOW CHANCE CATEGORY GENERALLY EAST OF A NORFOLK THROUGH LINCOLN
AND BEATRICE LINE AND SLIGHT CHANCE TO THE WEST.
TUESDAY WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS IN THE MID
90S. DEWPOINTS TO REACH THE MID 70S WITH UPPER 70S FROM EAST CENTRAL
NEBRASKA INTO SOUTHWEST IOWA. THIS WILL RESULT IN HEAT INDEXES OF
105 TO A HIGHS AS 110. NEXT SHIFT WILL NEED TO CONSIDER THE NEED FOR
A HEAT ADVISORY. REGARDING THUNDERSTORM POTENTIAL...THE ATMOSPHERE
WILL BE VERY UNSTABLE WITH MU CAPES AS HIGH AS 6000 J/KG AND DEEP
LAYER SHEAR AROUND 30 KTS. MODELS DO NOT SHOW A SUFFICIENT
TRIGGER...SO DEVELOPMENT WILL BE CONDITIONAL. WILL CARRY A SLIGHT
CHANCE FOR THE AFTERNOON ALL AREAS...THEN A SLIGHT CHANCE FOR
NORTHEASTERN COUNTIES TUESDAY NIGHT AS A COLD FRONT MOVES IN.
FOR WEDNESDAY THROUGH FRIDAY...
A STRONG SHORTWAVE MOVING ALONG THE CANADIAN BORDER TUESDAY NIGHT
WILL BRING A COLD FRONT THROUGH THE CWA ON WEDNESDAY LOWERING HIGHS
TO THE UPPER 80S TO AROUND 90. FORECAST IS DRY UNTIL FRIDAY WITH A
SLIGHT CHANCE NORTHERN HALF WITH CONVERGE NEAR A STALLED FRONT
INCREASING IN THE AFTERNOON. THE GFS CONTINUES TO SHOW ORGANIZED
CONVECTION ALONG AND NORTH OF THE FRONT FOR FRIDAY NIGHT. HIGHS
THURSDAY AND FRIDAY TO RANGE FROM 85 TO 89.
WILL NOT MAKE ANY CHANGES TO THE FORECAST BEYOND FRIDAY.
ROBERG
&&
.AVIATION...
FOR THE 06Z TAFS...
+TSRA TO CONTINUE TO AFFECT KOMA TIL 11Z WITH +TSRAGS POSSIBLE.
HEAVY THUNDERSTORMS SHOULD END OR SLIDE EAST OF TERMINAL BY 13Z.
MVFR CIGS TO CONTINUE AT KOFK AS LONG AS 17Z. VFR CONDITIONS SHOULD
CONTINUE FOR KLNK.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$