FXUS63 KOAX 040211
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
911 PM CDT FRI JUN 3 2011
.DISCUSSION...
GOING FORECAST IN PRETTY GOOD SHAPE THIS EVENING...BUT WILL UPDATE
TO MAKE SOME MINOR CHANGES. AS EXPECTED...THUNDERSTORMS HAVE
DEVELOPED IN DEEPLY MIXED BOUNDARY LAYER OVER NORTHWEST KANSAS
JUST BEHIND THE SURFACE COLD FRONT. THESE CONTINUE TO MOVE TO THE
NORTHEAST TOWARD SOUTHERN NEBRASKA. PER EVENING SOUNDINGS...THE
ATMOSPHERE AHEAD OF THESE STORMS EXHIBITS STRONG INHIBITION AND
MARGINAL INSTABILITY/MOISTURE. WITH A LOSS BOUNDARY LAYER HEATING
AND INHIBITION CONTINUING TO INCREASE...WE EXPECT THESE STORMS TO
WEAKEN AS THE HEAD TO OUR FA.
LATEST RADAR TRENDS INDICATE SOME INCREASE IN CONVECTIVE
COVERAGE TO THE NORTH OF THE MAIN STORMS...OVER SOUTHWEST
NEBRASKA WELL BEHIND THE SURFACE COLD FRONT CLOSER TO THE 850 MB
FRONT. LATEST SHORT TERM MODELS INDICATE THAT THE LOW LEVEL JET
WILL INCREASE FROM KANSAS INTO SOUTHERN NEBRASKA LATE THIS
EVENING...INCREASING MASS CONVERGENCE ALONG THE 850 MB FRONT. THUS
WE MAY SEE SOME INCREASE IN STORM COVERAGE LATE THIS EVENING FROM
CENTRAL NEBRASKA INTO NORTHEAST NEBRASKA OVERNIGHT...THOUGH
COVERAGE SHOULD GENERALLY REMAIN SCATTERED. THUS WILL ALIGN POPS
TO CENTER HIGHER CHANCES IN NORTHWEST CWA AND LOWER POPS OVER
SOUTHEAST NEB. THESE STORMS SHOULD HAVE LITTLE CHANCE IN BEING
SEVERE WITH LIMITED INSTABILITY AND WEAK SHEAR.
OTHER ELEMENTS OF THE FORECAST ARE ON TRACK WITH LITTLE CHANGES TO
WINDS AND OVERNIGHT LOWS.
NEW UPDATES WILL BE OUT BY 10 PM.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 343 PM CDT FRI JUN 3 2011/
SHORT TERM...TONIGHT...A COLD FRONT IS FORECAST TO STALL OUT
TONIGHT SOMEWHERE IN THE VICINITY OF SERN NEBRASKA/SWRN IOWA AS
UPPER RIDGE BUILDS BACK TOWARD ROCKIES AS UPPER SHORT WAVE ENERGY
LIFTS INTO CANADA. MODELS DISAGREE ON HOW FAR SOUTH FRONT WILL PUSH
TONIGHT WITH 12Z GFS KEEPING IT FARTHER NW. EVEN THOUGH 12Z NAM WAS
FARTHER SE WITH FRONTAL PLACEMENT AT 12Z SAT...IT WAS SIMILAR TO GFS
WITH QPF PLACEMENT SPREADING IT FROM SWRN TO NERN NEBRASKA
OVERNIGHT. WARM MID LEVEL TEMPERATURES ARE A DEFINITE WILD
CARD...ESPECIALLY THIS EVENING WHERE THEY COULD LIMIT DEVELOPMENT
ALONG FRONT. NONETHELESS...DECIDED TO CARRY SMALL POPS ALONG FRONT
IN THE EVENING BEFORE ALLOWING THEM TO INCREASE DIURNALLY OVERNIGHT
AS LOW LVL JET ACTS UPON BOUNDARY. THEN PREVIOUS FORECAST POPS
LOOKED GOOD AND NO CHANGES WERE MADE. DID RAISE LOWS A TOUCH INTO
LNK/OMA VCNTY AS SOME QUESTION AS TO HOW FAR SE COOLER TEMPERATURES
WILL PUSH TONIGHT.
FOR SATURDAY THROUGH MONDAY...STALLED SURFACE BOUNDARY OVER
SOUTHEAST NEBRASKA WILL BE THE FOCUS FOR DEVELOPMENT OF CONVECTION
ON SATURDAY AND SUNDAY. MUCH OF THE THUNDERSTORM ACTIVITY IS
EXPECTED TO NOCTURNAL WHEN LOW LEVEL JET INCREASES. AT THIS TIME...
THUNDERSTORM ACTIVITY IS EXPECTED TO BE OVER SOUTHEAST NEBRASKA INTO
SOUTHWEST IOWA. FRONT IS EXPECTED TO BEGIN LIFTING NORTHWARD ON
SUNDAY AND MONDAY AS UPPER LEVEL RIDGING BUILDS IN THE PLAINS.
THUNDERSTORM ACTIVITY SHOULD THEN LIFT NORTHWARD INTO NORTHEAST
NEBRASKA AND WESTERN IOWA ON SUNDAY AND SUNDAY NIGHT. TEMPERATURES
WILL GRADUALLY WARM UP TO UPPER 80S AND LOWER 90S BY MONDAY.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY. RIDGING ACROSS THE CENTRAL
US WILL ALLOW FOR ONE MORE HOT DAY TUESDAY WITH HIGHS IN THE 90S. AS
THE RIDGE SHIFTS TO THE EAST...ANOTHER COLD FRONT IS EXPECTED TO
MOVE INTO NORTHEAST NEBRASKA TUESDAY NIGHT...WHICH COULD TRIGGER AN
ISOLATED THUNDERSTORM...AND THEN THERE IS SOME QUESTION WHETHER THE
FRONT COULD TRIGGER ANYTHING DURING THE DAY ON WEDNESDAY AS IT
SLOWLY SAGS SOUTHWARD TOWARD I80. FOR NOW...WILL KEEP WEDNESDAY
DRY...BUT WILL MAINTAIN PRECIPITATION CHANCES WEDNESDAY NIGHT AS THE
FRONT REMAINS STALLED IN THE AREA...A MORE FAVORABLE PATTERN FOR
NOCTURNAL STORMS AS THE LOW LEVEL JETS INTERACTS WITH THE BOUNDARY.
APPEARS TO BE A BETTER CHANCE OF A FEW STORMS HOLDING TOGETHER
THROUGH THE DAY THURSDAY...ESPECIALLY IN THE MORNING. AT THE SAME
TIME...AN UPPER LEVEL WAVE ENTERS FROM THE CENTRAL ROCKIES...AND
PROVIDES ANOTHER CHANCE FOR HEAVIER THUNDERSTORMS THURSDAY NIGHT.
THIS IMPULSE DOES HAVE FORWARD MOTION...AND IT COULD BE EAST OF THE
BY DAYBREAK FRIDAY...BUT THE GFS IS A BIT SLOWER...THUS HELD ONTO AT
LEAST SMALL POPS NEAR THE END OF THE PERIOD DUE TO UNCERTAINTIES.
CHERMOK/SMITH/DEWALD
AVIATION...
18Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WEAK FRONT WILL PUSH
THROUGH KOMA/KLNK AREAS TOWARD MIDNIGHT. WINDS SHOULD DECREASE AND
BECOME SRLY AHEAD OF FRONT EARLY THIS EVENING AT KOMA/KLNK BEFORE
SHIFTING TO NNE. ALTHOUGH THERE IS A SMALL CHANCE THAT
THUNDERSTORMS WILL DEVELOP ON FRONT THIS EVENING...ACTIVITY IS MORE
LIKELY FARTHER SW AND THEN EXPANDING TOWARD NERN NEBRASKA LATER
TONIGHT. THUS CHC POPS WERE JUST CARRIED IN KOFK WITH 18Z ISSUANCE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$