FXUS63 KOAX 050853
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
353 AM CDT TUE JUL 5 2011
.DISCUSSION...
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES AND SEVERE WEATHER
POTENTIAL OVER THE NEXT COUPLE OF DAYS.
AT 08Z...A COLD FRONT EXTENDED FROM NORTHERN MINNESOTA INTO SOUTH
DAKOTA...WITH A NUMBER OF OUTFLOW BOUNDARIES RELATED TO CONVECTION
FROM MINNESOTA INTO SOUTH DAKOTA AND NEBRASKA. LATEST WSR-88D
RADAR INDICATED CLUSTERS OF STORMS ALONG THE FRONT AND OUTFLOW
BOUNDARIES. THERE ARE NUMEROUS FLASH FLOOD WARNINGS IN EFFECT OVER
PARTS OF SOUTH DAKOTA. OF NOTE ON THE WATER VAPOR SATELLITE IMAGERY
WAS THAT THERE WAS A MONSOONAL MOISTURE CONNECTION. MODEL
FORECASTS SHOW PRECIPITABLE WATER VALUES INCREASING TO 1.5 TO 2
INCHES ACROSS THE FORECAST AREA TODAY AND THIS EVENING AND THIS
GETS PUSHED TOWARD THE NEBRASKA/IOWA BORDER AND INTO KANSAS BY 06Z
AND REMAINS IN THIS AREA WEDNESDAY NIGHT.
TODAY...A SHORTWAVE TROF MOVING THRU THE DAKOTAS AND MINNESOTA
WILL DRAG A COLD FRONT INTO THE AREA. MEANWHILE...A SPEED MAX
AROUND 40KT AT H5 WILL TRACK ACROSS THE STATE TODAY. THE STORMS IN
MINNESOTA ARE DROPPING SOUTH...WHILE THE STORMS IN SOUTH DAKOTA
APPEAR TO BE LIFTING NORTH. ALSO...THERE HAVE BEEN STORMS
DEVELOPING SOUTH OF ONEILL. ALTHOUGH CONVECTION MAY GET GOING
AHEAD OF THE FRONT...THE THUNDERSTORMS ARE MOST LIKELY IN THE
VICINITY OF THE FRONT. TENDED TO GO MORE WITH A GFS/ECMWF SOLUTION
ON THE PRECIPITATION. THIS MORNING THERE WILL BE ONGOING
CONVECTION FROM SOUTH DAKOTA INTO NORTHEAST NEBRASKA AND PARTS OF
WEST CENTRAL IOWA. BY NOON THE FRONT WILL BE CLOSER TO THE
NEBRASKA BORDER. BY EVENING THE FRONT IS OVER SOUTHERN NEBRASKA.
WITH THE MONSOONAL MOISTURE WILL NEED TO KEEP AN EYE ON THE
RAINFALL. DEWPOINTS AT H7 AND AT H8 ARE BOTH ON THE HIGH SIDE AND
CONSIDERED A FLASH FLOOD WATCH. FLASH FLOOD GUIDANCE IN NORTHEAST
NEBRASKA IS MAINLY 2 TO 3 INCHES AND HOUR...HOWEVER IS ONLY 1 TO 2
INCHES FARTHER SOUTH. THERE IS CONVERGENCE ON THE FRONT ALONG WITH
THE SHORTWAVE TOPPING THE RIDGE. THE LOW LEVEL JET SEEM TO GET
GOING MORE OVER CENTRAL NEBRASKA AND THIS MAY FOCUS THE HEAVIER
RAINS JUST WEST OF OUR AREA. FORECAST SOUNDINGS SHOW INSTABILITY
INCREASING TO OVER 3K J/KG AND BECOMING SURFACE BASED. STORMS THAT
FORM WILL BE CAPABLE OF PRODUCING SEVERE WEATHER WITH LARGE HAIL
AND DAMAGING WINDS IN ADDITION TO LOCALLY HEAVY RAIN. HIGH
TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER AND FOR NOW HAVE
HIGHS IN THE 80S NORTH AND 90S SOUTH.
THE FRONT SETTLES A LITTLE FARTHER SOUTH WITH THE HIGHEST
PRECIPITABLE WATER FROM SOUTHERN NEBRASKA INTO KANSAS. ANOTHER
SHORTWAVE TROF WILL MOVE ACROSS THE STATE. THIS SHOULD FOCUS
STORMS OVER THE WESTERN HIGH PLAINS INTO CENTRAL NEBRASKA AND
CENTRAL KANSAS...SPREADING INTO EASTERN NEBRASKA. ONCE AGAIN THE
CONVECTIVE COMPLEX WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN
WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. AT THIS TIME THE LOW
LEVELJET APPEARS TO FOCUS THIS FROM SOUTHERN NEBRASKA INTO KANSAS.
ALTHOUGH THERE MAY BE SOME SPOTTY ACTIVITY...THE PRECIPITATION SHOULD MOVE
OUT OF THE AREA FOR THURSDAY AND THURSDAY NIGHT.
FRIDAY A MID LEVEL RIDGE BUILDS IN AND THE NEXT WEAK SHORT WAVE
TROF ADVANCES ACROSS THE NORTHERN PLAINS SATURDAY. GRADUALLY THE
SURFACE FRONT SAGS INTO THE AREA SUNDAY. THEN LINGERS OVER THE
AREA MONDAY. DID NOT MAKE ANY CHANGES AS THE SUMMER PATTERN
REMAINS UNSETTLED FOR THIS FRIDAY THRU MONDAY PERIOD.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
HIGH HUMIDITY WILL CREATE CONDITIONS FAVORABLE FOR LIGHT FOG
FORMATION DURING THE NIGHT...AS WELL AS A TREND TOWARD LOWERING
CLOUDS THROUGH THE TAF PERIOD. COLD FRONT MOVING THROUGH THE REGION
WILL LIKELY TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS...BUT TIMING
AT SPECIFIC TAF SITES IS CHALLENGING. CLUSTERS OF STORMS OVER SOUTH
DAKOTA AND NORTH CENTRAL NEBRASKA SHOULD REMAIN NORTH OF TAF SITES
WITH POSSIBLE EXCEPTION OF KOFK GETTING BRUSHED BY SHOWER ACTIVITY
THIS MORNING. OUTFLOW FROM AREAS OF SHOWERS AND THUNDERSTORMS AS
WELL AS THE FRONT ITSELF WILL CAUSE VARIATIONS IN THE WINDS ON
OCCASION.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY/NIETFELD