FXUS63 KOAX 060813
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
313 AM CDT FRI MAY 6 2011
.DISCUSSION...
TEMPERATURES AND SMALL PRECIPITATION CHANCES THROUGH EARLY NEXT WEEK
ARE THE PRIMARY FORECAST CONCERNS.
NEARLY ZONAL UPPER FLOW FROM THE PACIFIC INTO THE PLAINS THIS
MORNING WILL UNDERGO A SHIFT TO A WESTERN TROUGH AND EASTERN RIDGE
PATTERN BY EARLY NEXT WEEK. SEVERAL IMPULSES MOVING INTO THE REGION
WILL BRING OFF AND ON THUNDERSTORM CHANCES DURING THE TRANSITION...
AND PERSISTENT FLOW OFF THE GULF OF MEXICO WILL DRAW MOISTURE INTO
THE CENTRAL PLAINS. THAT MOISTURE WILL SURGE NORTH TUESDAY AND
WEDNESDAY OF NEXT WEEK...BUT BEFORE THEN WILL OCCASIONALLY WORK INTO
THE CWA AS IMPULSES APPROACH.
THE FIRST OF THESE IMPULSES WAS MOVING THROUGH CENTRAL MONTANA THIS
MORNING. MODELS MOVE THIS FEATURE THROUGH THE NORTHERN PLAINS
TODAY...BUT THE SOUTHERN PERIPHERY OF SHORTWAVE ENERGY WILL SWEEP
THROUGH EASTERN NEBRASKA AND WESTERN IOWA AS SURFACE DEW POINTS
APPROACH 50 AHEAD OF ATTENDANT SURFACE BOUNDARY. HAD SCATTERED
SHOWERS IN THIS SAME PATTERN ON THURSDAY...BUT LAPSE RATES ARE NOT
NEARLY AS STEEP THIS AFTERNOON OWING TO WARMER MID LEVEL
TEMPERATURES. BETTER HEATING/MOISTURE WILL RESIDE ALONG THE KANSAS
BORDER...SO WILL MAINTAIN A SMALL CHANCE FOR THUNDERSTORMS THERE
THIS EVENING. HIGHS TODAY WILL BE WELL INTO THE 70S WITH GUSTY SOUTH
WINDS OVER 20 MPH.
SATURDAY SHOULD BE DRY WITH LIGHT NORTHERLY WINDS. HIGHS AGAIN IN
THE 70S WITH PLENTY OF SUNSHINE.
THEN SEVERAL CHANCES FOR THUNDERSTORMS ENTER THE FORECAST SATURDAY
NIGHT THROUGH MONDAY AS WE TRANSITION INTO SOUTHWESTERLY FLOW
ALOFT. SOUTHEAST WINDS WILL RETURN SATURDAY NIGHT AS A SHORTWAVE
ROLLS THROUGH THE DAKOTAS. THETA-E CONVERGENCE WILL RESIDE NORTH OF
NORTHEAST NEBRASKA...BUT AT LEAST A SMALL CHANCE FOR STORMS THERE
MAINLY AFTER MIDNIGHT. THEN WILL MAINTAIN GOING SLIGHT CHANCE FOR
STORMS POPPING UP DURING THE DAY SUNDAY AS LOW LEVEL MOISTURE MOVES
NORTH AND MID LEVEL TEMPERATURES REMAIN MODERATELY COOL. BETTER
STORM CHANCES COME SUNDAY NIGHT WITH SURFACE/850 WARM FRONT SETTING
UP IN SOUTHEAST NEBRASKA PROVIDING FOCUS FOR CONVECTION. GFS SHOWS
ROBUST ELEVATED CAPE OVER 2000 J/KG AT 06Z MONDAY...SUGGESTING
POTENT STORMS POSSIBLE. THE ELEVATED INSTABILITY SHOULD LIFT
NORTHEAST OF THE CWA MONDAY MORNING...LEAVING THE AFTERNOON DRY AND
WARM. HAVE HIGHS APPROACHING 90 IN OUR SOUTH AS GFS/ECMWF SHOW 850
TEMPS IN THE LOW TO MID 20S C MONDAY AFTERNOON.
WILL LEAVE THE REST OF THE FORECAST BASICALLY UNCHANGED FOR TUESDAY
THROUGH THURSDAY. UPPER TROUGH TO THE WEST WILL MAKE A SLOW PUSH
INTO THE PLAINS AS SOUTHERLY FLOW DRAWS 60S SURFACE DEWPOINTS INTO
THE REGION. DIFFLUENT FLOW ALOFT COMBINED WITH STEEPENING LAPSE
RATES AND INCREASING INSTABILITY SUGGEST A DECENT SHOT AT SEVERE
STORMS EITHER TUESDAY OR WEDNESDAY...OR BOTH...AS SURFACE FRONT
PUSHES INTO THE CWA.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
SFC WINDS WILL INCREASE AROUND 15Z THIS MORNING AHEAD OF AN
APPROACHING COLD FRONT. AT OFK EXPECT WIND SHIFT FROM S TO NW AROUND
07/01Z...OMA AT 07/03Z...AND LNK AT 07/02Z.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$