FXUS63 KOAX 030811
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
311 AM CDT FRI JUN 3 2011
.DISCUSSION...
FRONTAL BOUNDARY LINGERING NEAR THE CWA AND ASSOCIATED PRECIPITATION
CHANCES OVER THE NEXT FEW DAYS ARE THE PRIMARY FORECAST CONCERNS.
UPPER AIR PATTERN OF RIDGING IN THE MISSISSIPPI VALLEY AND TROUGHING
ALONG THE WEST COAST WILL UNDERGO SOME AMPLITUDE CHANGES OVER THE
NEXT WEEK...BUT MEAN POSITION OF RIDGE TO OUR EAST AND TROUGH TO OUR
WEST WILL PERSIST. THIS MORNING A SHORTWAVE MOVING EAST THROUGH
MONTANA WILL PUSH THROUGH NORTH DAKOTA AND ON TO THE EAST SATURDAY.
THIS WILL HELP TO NUDGE A COLD FRONT THROUGH OUR CWA...AND ALSO
FLATTEN MISSISSIPPI VALLEY RIDGE SOMEWHAT.
THAT COLD FRONT EXTENDED FROM CENTRAL SOUTH DAKOTA THROUGH WESTERN
NEBRASKA EARLY THIS MORNING...AND WAS MAKING A SLOW PUSH TO THE
EAST. MODELS PLACE THIS FRONT IN OUR WESTERN CWA THIS MORNING...THEN
PUSH IT SLOWLY SOUTHEAST THROUGH THE DAY. WITH MAIN UPPER FLOW WELL
TO THE NORTH...THE FRONT WILL HAVE LITTLE REASON TO CLEAR THE CWA TO
THE SOUTH...AND EXPECT IT TO LINGER NEAR OUR SOUTHERN BORDER AT
LEAST INTO SUNDAY. THIS WILL BE THE FOCUS FOR THUNDERSTORM ACTIVITY
OVER THE NEXT SEVERAL DAYS.
ONLY CONVECTION OCCURRING THIS MORNING WAS IN SOUTH DAKOTA NEAR COLD
FRONT AND SURFACE LOW. WEAK MID LEVEL RETURNS WERE NOTED FROM KANSAS
INTO SOUTH CENTRAL NEBRASKA IN MID LEVEL MOISTURE PLUME. THAT
MOISTURE WILL INHIBIT HEATING SOMEWHAT THIS AFTERNOON...AND WILL
HOLD DOWN POTENTIAL INSTABILITY ALONG FRONTAL ZONE. STILL WEAK
CONVERGENCE ALONG THE FRONT COULD SPARK AN ISOLATED STORM LATE THIS
AFTERNOON IF BREAKS IN CLOUD COVER ALLOW TEMPS TO SOAR GIVEN MID 60S
OR HIGHER DEW POINTS IN PLACE. THINK MAIN RAIN CHANCES WILL COME
OVERNIGHT AS LOW LEVEL JET INCREASES AND RIDES OVER FRONTAL ZONE.
ONLY MODEST MID LEVEL INSTABILITY IS SHOWN ON FORECAST SOUNDINGS...
BUT MAY BE ENOUGH TO SUPPORT A FEW ELEVATED SEVERE HAIL STORMS.
LINGERING MORNING STORMS ARE POSSIBLE OVER A GOOD PART OF THE
CWA SATURDA...BUT FOCUS IN THE AFTERNOON WILL RETURN TO FRONTAL
ZONE ALONG OR JUST SOUTH OF OUR SOUTHERN BORDER. TEMPERATURES IN
THE UPPER 80S WITH POOLING DEW POINTS NEAR 70 WILL LEAD TO 3000
J/KG OF SURFACE BASED CAPE IN THE LATE AFTERNOON. SOMEWHAT COOLER
MID LEVEL TEMPERATURES ON NORTHERN EDGE OF FLATTENING RIDGE SHOULD
ALLOW CONVECTION TO FIRE ALONG FRONTAL CONVERGENCE ZONE. MODEST
35KTS OF 0-6KM BULK SHEAR SUGGESTS A SLIGHT SEVERE RISK OF HAIL
AND WINDS...WITH AN ISOLATED TORNADO POSSIBLE GIVEN LOW LEVEL
SHEAR ALONG FRONTAL BOUNDARY.
STORMS SHOULD MOVE EAST WITH A TENDENCY TO SPREAD NORTH WITH TIME
OVERNIGHT AS RIDGE BEGINS TO SHIFT NORTH WITH APPROACH OF A
SHORTWAVE FROM WESTERN TROUGH. THIS PROCESS CONTINUES ON SUNDAY
WHICH WILL DRAG/BRIDGE WARM FRONT NORTH INTO OUR NORTH AND NORTHEAST
CWA. RISING HEIGHTS AND WARMING MID LEVEL TEMPERATURES SHOULD CAP
ATMOSPHERE OVER MOST OF THE CWA SUNDAY AND SUNDAY NIGHT...WITH ONLY
SMALL CHANCES NEAR EXPECTED WARM FRONTAL POSITION IN THE NORTH. DRY
AND WARM FORECAST FOR MONDAY THROUGH WEDNESDAY WITH MAIN STORM TRACK
TO OUR NORTHWEST. RIDGE BEGINS TO BREAK DOWN BY THURSDAY...ALLOWING
A CHANCE FOR STORMS TO ENTER THE FORECAST THEN.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD OUTSIDE OF
POTENTIAL THUNDERSTORMS LATER FRIDAY NIGHT. COLD FRONT SLIDING
THROUGH THE CWA WILL SWITCH WINDS TO THE NORTHWEST GRADUALLY
DURING THE DAY. THUNDERSTORMS ARE POSSIBLE AT ALL TAF SITES AFTER
00Z...BUT MORE LIKELY AFTER 06Z...WITH ATTENDANT MVFR CIGS/VSBYS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
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