FXUS63 KOAX 220922
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
422 AM CDT WED SEP 22 2010
.DISCUSSION...
FORECAST CHALLENGES WILL CONTINUE TO BE LOCATION AND TIMING OF
CONVECTION ALONG WITH TEMPS AND WINDS THROUGH THURSDAY EVENING.
THE SFC FRONT WAS LOCATED SOUTH OF KLNK AND NEAR KOMA/KHNR. THERE
HAS BEEN SPOTTY PRECIPITATION SOUTH OF THE FNT WITH LINGERING
SHORTWAVE TROF ENERGY/THETA-E ADVECTION. CLDS WERE NOTED ALONG AND
NORTH OF THE FNT...COVERING MUCH OF ECNTRL NEB AND WRN IA. THE H85
WINDS ARE BEGINNING TO PICK UP OVR THE WRN PLAINS AND SHORTWAVE
TROF ENERGY IN THE WESTERLY FLOW WAS ALSO INCREASING WITH CONVECTION
EXPANDING FM OGALLALA TOWARD VTN. AS THE WAVE MOVES NORTHEAST AND
THE SFC FRONT LIFTS NORTH...THE SHORT TERM MODELS FURTHER EXPAND
THE TSRA INTO CNTRL AND NORTHEAST NEBRASKA. MEANWHILE THE NOSE OF
A STRONG UPPER LEVEL JET OVR UTAH...COUPLE WITH THE JET OVR SRN
CANADA ENHANCES THE UPR LEVEL DIV OVR THE DAKOTAS. HAVE THE
HIGHEST CONFIDENCE IN THE NORTH AND HAVE PLACED HIGHEST POPS
THERE. FARTHER SOUTH THERE IS MORE OF A QUESTION IN REGARD TO
COVERAGE...THUS DECREASED COVERAGE TO SCT AND THEN ISOLATED.
INSTABILITY INCREASES TO 2000-3000 J/KG AND DEEP LAYER SHEAR IS 45 TO
50KTS IN THE NORTH AND THE SFC FNT IS NEARBY...THUS SVR STORMS
WILL BE POSSIBLE ESPECIALLY IN NE NEB. SOUTH WINDS SHOULD BE
BREEZY AND THIS SHOULD HELP HIGHS TOP OUT IN THE 80S...HOWEVER
THE CLOUDS MAY HOLD TEMPS DOWN IN THE NORTH.
TONIGHT...THE FULL LATITUDE MID LEVEL TROF OVR THE WRN U.S. MOVES
OVER THE ROCKIES...WITH A STRENGTHENING LOW LEVEL JET AROUND
50KTS. THIS SHOULD HELP EXPAND THE PRECIP FROM MEXICO NORTH INTO
THE PLAINS AND ALONG THE FRONT ACRS MN AND WI. AGAIN THE BEST CHC
FOR RAIN WILL BE IN THE NORTHWEST...NORTHWEST OF A LINE FROM
COLUMBUS TO ONAWA IOWA. MOIST SOUTH FLOW SHOULD HOLD TEMPERATURES
UP...WELL ABOVE NORMAL IN THE UPR 60S TO AROUND 70.
THURSDAY THE MID LEVEL TROF SHIFTS EASTWARD WITH A LARGE AREA OF
RAIN...SHOWERS AND THUNDERSTORMS FROM NEB INTO THE DAKOTAS...MN AND WI.
THE SFC COLD FRONT GRADUALLY WORKS ACROSS THE FORECAST AREA WITH
GUSTY SOUTH WINDS AHEAD OF THE FNT. AT THIS TIME HAVE IT
WINDY...BUT BELOW WIND ADVISORY CRITERIA. STRONG 50 TO 60 KT H85
WINDS...SO THIS WILL NEED TO BE WATCHED. AM COUNTING ON THE CLDS
HINDERING FULL MIXING. HIGHS IN THE NORTH IN THE LOWER 70S TO THE
LOWER 80S FARTHER SOUTH. SVR STORMS AND LOCALLY HEAVY RAIN WILL BE
POSSIBLE WED-THU EVENING. PRECIP WAT INCREASES TO 1.5 TO 2.25 AND
IS ACCOMPANIED BY STRONG DYNAMICS.
SOME STORMS MAY LINGER AFTER MIDNIGHT THURSDAY NIGHT...HOWEVER THE
BULK OF THE PRECIP SHOULD BE OUT OF THE AREA. FRIDAY STILL LOOKS
DRY. FRIDAY NIGHT INTO SATURDAY...A WAVE FM CANADA DROPS SOUTHEAST
INTO THE NORTHERN PLAINS...THE MODELS DIFFER ON HOW FAR SOUTH THE
PRECIP WILL DEVELOP...BUT THINK THE WAVE IS STRONG ENOUGH TO
ADD POPS IN THE NORTH FRIDAY NIGHT AND TO KEEP A MENTION OF
SHOWERS IN SATURDAY.
NUDGED TEMPS DOWN SAT NIGHT THRU MON AS THIS TROF CLOSES OFF
SOMEWHERE IN THE MIDWEST. MAY NEED TO MAKE SIG CHG ADJUSTMENTS AS
THE ECWMF AND THE GFS PATTERS ARE MUCH COOLER THAN CURRENT FCST.
DAYSHIFT WILL HAVE A FULL SUITE OF MODELS TO LOOK AT IN ADDITION
TO COORD WITH SURROUNDING FO/S AND HPC. DIDN'T WANT TO STRAY TOO
FAR FM THE ENS MEANS TO THE LOW SIDE OF GUID AS IT WOULD HAVE PUT
US OUT OF TOLERANCE WITH OUR NEIGHBORS. PLACEMENT FARTHER EAST OF
THE CLOSED LOW WOULD NOT BE AS COOL...SO JUST TWEAKED LOWER FOR NOW.
&&
.AVIATION...
06Z TAFS
IFR CIGS AND VSBYS BETWEEN 3SM AND 5SM WILL LINGER AT ALL EASTERN
NEBRASKA TAF SITES THROUGH ABOUT 15Z...NORTH OF A WARM FRONT IN
SOUTHEAST NEBRASKA. AS THAT FRONT LIFTS NORTH DURING THE
MORNING...GUSTY SOUTH WINDS AND IMPROVING CIGS/VSBYS WILL RESULT
LEAVING VFR CONDITIONS FOR MOST OF THE DAY AFTER 18Z. SOUTH WINDS
WILL AVERAGE 20KTS WITH GUSTS TO 30KTS MUCH OF THE AFTERNOON.
SCATTERED THUNDERSTORMS ARE POSSIBLE BEFORE 18Z NEAR KOFK...WITH A
CONTINUED CHANCE THROUGH THE AFTERNOON AND EVENING. THUNDERSTORMS
ARE ALSO POSSIBLE AFTER 06Z NEAR KOMA AND KLNK WITH ATTENDANT
POTENTIAL IFR CONDITIONS.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY/DERGAN