FXUS63 KOAX 100102
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
802 PM CDT SAT JUL 9 2011
.UPDATE...
HAVE UPDATED TO ADJUST OVERNIGHT POPS.
&&
.DISCUSSION...
CONVECTION HAS FAILED TO DEVELOP ALONG THE CONFLUENT LOW LEVEL
FLOW OVERNIGHT NORTHEAST NEB THIS EVENING. A FEW ISOLATED STORMS
DID GET GOING OVER CENTRAL SD...BUT THESE WILL MOST LIKELY NOT
MAKE IT INTO OUR NORTHEAST NEB ZONES AND THUS HAVE REMOVED
EVENING POPS. THE NEXT QUESTION BECOMES OVERNIGHT POPS. 00Z UPPER
AIR ANALYSIS INDICATED A GOOD DEAL OF MOISTURE AND INSTABILITY
OVER THE FA THIS EVENING. JUST TO THE SOUTH THOUGH...SOME VERY HOT
850 MB TEMPERATURES WERE OBSERVED AT KDDC. THE RUC INDICATES THAT
SOME OF THIS HOT AIR OFF THE SURFACE WILL SHIFT NORTHEAST
OVERNIGHT CREATING A LESS FAVORABLE ENVIRONMENT FOR CONVECTION
WITH INCREASING INHIBITION. WILL NOT REDUCE POPS AFTER MIDNIGHT TO
MUCH YET...BUT WILL VIEW SOME OF THE UPCOMING NEW MODEL GUIDANCE
FROM 00Z AND SEE IF THIS TREND CONTINUES. IF THIS IS INDEED THE
CASE...WILL HAVE TO LOWER OVERNIGHT POPS AS DEVELOPMENT OF NEW
STORMS AND/OR MOVEMENT OF WESTERN HIGH PLAINS CONVECTION WOULD BE
LESS LIKELY INTO OUR FA.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 334 PM CDT SAT JUL 9 2011/
DISCUSSION...
RAIN CHANCES AND AMOUNTS OVER THE NEXT SEVERAL NIGHTS ARE THE
PRIMARY FORECAST CONCERNS.
UPPER RIDGE WAS STRETCHED OUT THROUGH THE SOUTHERN CONUS TODAY WITH
RELATIVELY FAST-MOVING WESTERLY MID LEVEL FLOW OVER THE CENTRAL AND
NORTHERN PLAINS. UNDER THOSE WESTERLIES...A FRONTAL BOUNDARY WAS
SITUATED FROM EASTERN SOUTH DAKOTA INTO NORTHERN NEBRASKA...AND THAT
FRONT WILL BE A FOCUS FOR OUR RAIN CHANCES THROUGH EARLY WEEK...WITH
SEVERAL IMPULSES ROLLING THROUGH THE UPPER FLOW PROVIDING HELP. A
MOIST AND POTENTIALLY UNSTABLE AIRMASS WILL REMAIN IN PLACE AS
SURFACE DEW POINTS REMAIN IN THE UPPER 60S TO MIDDLE 70S. SO
AFTERNOON HEATING ALONG FRONTAL ZONE...ALONG WITH UPPER WAVES
TRIGGERING OVERNIGHT MCS ACTIVITY.
THIS AFTERNOON INSTABILITY WAS FOCUSED ALONG FRONTAL BOUNDARY TO OUR
NORTHWEST...BUT A POCKET OF LOW CINH AND CUMULUS WAS NOTED NEAR AND
NORTHWEST OF NORFOLK. THIS AREA HAS BEEN EXPANDING SLOWLY OVER THE
PAST HOUR...SO WE COULD SEE SOME DEVELOPMENT THERE. AND ALSO ALONG
FRONT IN SOUTH DAKOTA THAT WILL EVENTUALLY WORK INTO NORTHEAST
NEBRASKA. LATER TONIGHT...MCS IS EXPECTED TO DEVELOP IN SOUTHWEST
NEBRASKA AND TRACK EAST INTO SOUTHEAST AND EAST CENTRAL NEBRASKA BY
12Z. THETA-E ADVECTION WITH MODERATE LOW LEVEL JET SHOULD MAINTAIN
ANY STORMS THAT DEVELOP IN THE HIGH PLAINS. THIS ACTIVITY SHOULD
PUSH OFF TO THE EAST SUNDAY MORNING LEAVING MUCH OF THE DAY DRY OVER
ALL OF THE CWA.
HOWEVER SIMILAR SCENARIO WILL LIKELY PLAY OUT SUNDAY AFTERNOON/NIGHT
AS FRONTAL BOUNDARY REPOSITIONS ITSELF JUST NORTHWEST OF THE CWA
DURING AFTERNOON HEATING. MORE STORMS ARE POSSIBLE IN OUR NORTHWEST
BEFORE 00Z NEAR FRONTAL ZONE...BUT BETTER CHANCES COME OVERNIGHT AS
ANOTHER WAVE TRIGGERS STORMS IN THE HIGH PLAINS DURING THE
AFTERNOON/EVENING. MCS WILL AGAIN MOVE INTO OUR CWA AFTER
MIDNIGHT...WITH FOCUS LIKELY NORTH OF INTERSTATE 80. AGAIN THIS
ACTIVITY SHOULD PUSH OFF TO THE EAST MONDAY MORNING.
AND YET A THIRD MCS IS LIKELY MONDAY NIGHT WITH ANOTHER IMPULSE
ROLLING THROUGH WESTERLY FLOW ALOFT. MODELS PAINT SURFACE FRONT OVER
OUR SOUTHERN CWA MONDAY AFTERNOON/EVENING WITH 850 BOUNDARY ALONG
OUR NORTHERN BORDER. MODEST LOW LEVEL JET WILL AGAIN SPARK
CONVECTION MONDAY EVENING/NIGHT...BUT FOCUS IS IN QUESTION AS
EARLIER CONVECTIVE CLUSTERS REORIENT SURFACE/850 BOUNDARIES. SO WILL
BE A LITTLE MORE BROAD-BRUSHED WITH POPS THROUGH TUESDAY MORNING.
WITH EACH OF THESE SYSTEMS...HEAVY RAIN IS A POSSIBILITY AS
PRECIPITABLE WATER VALUES REMAIN NEAR OR ABOVE 1.75 INCHES. AND
EAST-WEST ORIENTED BOUNDARIES WITH EASTWARD-MOVING COMPLEXES
SUGGEST TRAINING OF STORMS COULD PRODUCE LOCALIZED AMOUNTS WELL OVER
3 INCHES EACH NIGHT. SYSTEMS SHOULD TAKE SLIGHTLY DIFFERENT
LATITUDINAL TRACKS EACH NIGHT...SO WIDESPREAD FLOODING IS NOT
EXPECTED. BUT ANY BIG RAIN AMOUNTS WILL ONLY EXASPERATE FLOODING
ALONG THE MISSOURI RIVER.
AS WE HEAD INTO THE MIDDLE OF THE WEEK...UPPER RIDGE WILL BEGIN
BUILDING NORTH INTO OUR AREA. HOWEVER TUESDAY NIGHT AND WEDNESDAY
NIGHT WILL AGAIN PROVIDE A CHANCE FOR MCS DEVELOPMENT. BY THIS
TIME...THE FOCUS SHOULD MOVE TO OUR NORTHERN CWA AS WESTERLIES SHIFT
SLIGHTLY NORTH...BUT AGAIN LOCALLY HEAVY RAIN IS POSSIBLE.
HOT AND HUMID CONDITIONS ARE EXPECTED BY THE END OF THE WEEK WITH
UPPER RIDGE NOSING NORTH.
DERGAN
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
SEVERAL BOUNDARIES LOCATED OVER THE CENTRAL PLAINS THIS AFTERNOON
WILL INCREASE CHANCE OF CONVECTION DURING THE PERIOD AT ALL THREE
TAF SITES. VFR CONDITIONS EXPECTED OUTSIDE OF THUNDERSTORMS.
INITIAL DEVELOPMENT INDICATED FOR KOFK AREA 21Z-24Z AS NORTHERN
BOUNDARY APPROACHES NORTHERN NEBRASKA BORDER. SOME CHANCE LATER
TONIGHT AFTER 06Z FOR KLNK AS SOUTHERN BOUNDARY ACROSS KANSAS HELPS
FOCUS DEVELOPMENT. KOMA IN BETWEEN THESE TWO BOUNDARIES AND HAVE
KEPT MENTION OF CONVECTION OUT AT THIS TIME.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...HEAT ADVISORY FROM NOON TO 8 PM CDT SUNDAY FOR NEZ050-065-066-
068-078-088>093.
IA...NONE.
&&
$$