FXUS63 KOAX 140754
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
254 AM CDT THU JUL 14 2011
.DISCUSSION...
WITH UPPER RIDGE GRADUALLY BUILDING INTO THE REGION...HEAT AND
HUMIDITY ARE THE PRIMARY FORECAST CONCERNS THROUGH THE MIDDLE OF
NEXT WEEK.
SHORTWAVE THAT WAS NEAR THE FOUR CORNERS REGION 24 HOURS AGO HAS
TRACKED INTO THE NORTHERN PLAINS AND WAS MOVING INTO MINNESOTA THIS
MORNING. TRAILING LOBE OF VORTICITY COMBINED WITH ABUNDANT LAYER
MOISTURE AND INSTABILITY LIFTING NORTH NEAR SURFACE WARM FRONT HAS
LED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS INITIALLY OVER
CENTRAL NEBRASKA AND NORTHERN KANSAS...AND WERE PUSHING INTO
EASTERN NEBRASKA. INSTABILITY IS LACKING HERE SO STORMS WERE
HAVING A TOUGH TIME HOLDING TOGETHER. HOWEVER MORE POTENT STORMS
WERE JUST NORTH OF THE CWA NEARER UPPER WAVE. WILL MAINTAIN A
SMALL CHANCE FOR SHOWERS/STORMS IN OUR NORTH AND EAST THROUGH MID
MORNING...BUT MOST ACTIVITY SHOULD BE PUSHING OFF TO THE EAST
SHORTLY AFTER SUNRISE.
UPPER HIGH PRESSURE RIDGE WAS CENTERED OVER THE SOUTHERN PLAINS THIS
MORNING...AND HAS SPRAWLED WEST OVER THE LAST 24 HOURS AS NOTED BY
SUBTROPICAL JET/MOISTURE PLUME SHIFTING WEST AND NORTHWEST ON WATER
VAPOR IMAGERY. STORM TRACK WILL SHIFT NORTHWEST WITH TIME AS UPPER
RIDGE BUILDS NORTH AND WEST THROUGH THE WEEKEND AND MID LEVEL
TEMPERATURES CAP CONVECTION. HOWEVER UNTIL THEN...A FEW MAINLY
NIGHTTIME STORMS MAY CLIP OUR NORTHWEST CWA WHERE MID LEVEL TEMPS
ARE A BIT COOLER AND DEEPER MOISTURE RESIDES. WILL MAINTAIN OUR
CURRENT SLIGHT CHANCE POPS THERE FOR FRIDAY AND SATURDAY
MORNINGS...MAINLY BETWEEN MIDNIGHT AND SUNRISE.
TEMPERATURES WILL ONLY INCREASE AS WE HEAD INTO THE WEEKEND. GFS
AND ECMWF SHOW 500 MB HEIGHTS RISING INTO THE 5940-5990M RANGE BY
SATURDAY AFTERNOON AND MAINTAINING THOSE HEIGHTS THROUGH TUESDAY.
THIS WILL EASILY PUT HIGHS IN THE MID TO UPPER 90S. PERSISTENT
SOUTHERLY FLOW SHOULD KEEP AVERAGE DEW POINTS IN THE LOWER
70S...AND EVAPOTRANSPIRATION COULD EASILY BOOST THOSE INTO THE MID
AND UPPER 70S FROM SOUTHWEST IOWA THROUGH NORTHEAST NEBRASKA. THIS
COMBINATION WILL PUT HEAT INDICES IN THE 105-110 RANGE FOR ABOUT 5
DAYS IN A ROW BEGINNING FRIDAY AFTERNOON. WILL ISSUE AN EXCESSIVE
HEAT WATCH FOR THIS PROLONGED TIME PERIOD...AND COULD SEE WARNING
CRITERIA OVER 110 MET EARLY IN THE PERIOD WHEN DEW POINTS ARE
EXPECTED TO BE HIGHEST. AFTERNOON MIXING WILL PUSH DEW POINTS DOWN
INTO THE 60S FOR SOME AREAS THROUGH THIS PERIOD...BUT WHEN THAT
OCCURS TEMPERATURES WILL RESPOND HIGHER AS WELL. THUS HEAT INDICES
OVER 105 SHOULD BE MAINTAINED.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS CONTINUE EARLY THIS MORNING AT ALL TAF LOCATIONS.
THIS IS EXPECTED TO CONTINUE INTO THE MID MORNING HOURS BEFORE
CEILINGS LIFT INTO THE VFR RANGE. ISOLATED SHOWERS WILL REMAIN
POSSIBLE AT OMA/OFK INTO THE EARLY MORNING HOURS...BUT THE REST OF
THE TAF PERIOD IS EXPECTED TO BE DRY AT ALL LOCATIONS. BY EARLY TO
MID AFTERNOON THE CEILING IS EXPECTED TO SCT AND WE SHOULD JUST BE
LEFT WITH SOME HIGH LEVEL CLOUDS TOWARD THE END OF THE PERIOD WITH
LIGHT SOUTH AND SOUTHEAST SURFACE WINDS.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...EXCESSIVE HEAT WATCH FROM FRIDAY AFTERNOON THROUGH TUESDAY
EVENING FOR NEZ011-012-015>018-030>034-042>045-050>053-
065>068-078-088>093.
IA...EXCESSIVE HEAT WATCH FROM FRIDAY AFTERNOON THROUGH TUESDAY
EVENING FOR IAZ043-055-056-069-079-080-090-091.
&&
$$