SPC Jul 21, 2013 Day 4-8 Convective Outlook

Day 4-8 Outlook

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0313 AM CDT SUN JUL 21 2013

VALID 241200Z - 291200Z

...DISCUSSION...
A MEAN UPPER TROUGH WILL REMAIN ACROSS THE ERN CONUS WITH A RIDGE
OVER THE WRN STATES. MODELS ARE IN FAIRLY GOOD AGREEMENT DEPICTING A
SHORTWAVE TROUGH ROUNDING THE WRN RIDGE INTO THE CNTRL HIGH PLAINS
ON THU/D5...AHEAD OF A LARGE UPPER LOW WHICH WILL DEVELOP SWD INTO
THE UPPER MS VALLEY ON FRI/D6. THIS INITIAL SHORTWAVE COULD RESULT
IN AN MCS FROM SWRN NEB INTO WRN KS ON D5...WITH A THREAT OF
DAMAGING WINDS AND HAIL. HOWEVER...THERE ARE QUESTIONS IN REGARD TO
MOISTURE AND INSTABILITY...AS THE INITIAL ACTIVITY COULD BE
PRODUCING RAIN ON THE COOL SIDE OF THE SYNOPTIC BOUNDARY...WITH
RELATIVELY DRY SURFACE TRAJECTORIES FROM HIGH PRESSURE ACROSS THE MO
AND UPPER MS VALLEYS. STILL...A LOCALIZED SEVERE THREAT COULD
MATERIALIZE...BUT PREDICTABILITY IS TOO LOW CURRENTLY.

FROM FRI/D6 INTO SUN/D8...THIS LEAD SHORTWAVE TROUGH IS FORECAST TO
PHASE WITH THE LARGE LOW TO THE N...WHICH WILL EVENTUALLY SPREAD EWD
ACROSS THE GREAT LAKES AND OH VALLEYS...AND TO THE ATLANTIC COAST BY
D8. WHILE SOME SEVERE THREAT WILL LIKELY MATERIALIZE ALONG THE
ACTUAL LOW PRESSURE TRACK...THE SEVERE WEATHER THREAT IS NOT
EXPECTED TO BE PARTICULARLY WIDESPREAD AND PREDICTABILITY IS TOO LOW
FOR ANY OUTLOOK AREAS.

via SPC Forecast Products http://www.spc.noaa.gov/products/exper/day4-8/