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<br />_...1."....:.-,.-.-.,.. <br /> <br />.Jr\ <br /> <br />However, these results do not stand out clearly above the b~ck8round variability <br />in precipitation. <br />4) During lame hours on exper~ent81 days, blocking type [lov pTevented <br />the nucleant from che ground generator network fr~ .scending over the target <br />area (5.3% of the six-hour block.). There vaS tot.l or partial blockins of <br />.ffectlve entrainment of nuclei in 12.6% of the six-hour blocks. Under these <br />condition. the nucleant was carried well to the we~t or northwest of the tarlet <br />ar.a. When the following day wa. a not-seeded experimental day, it was often <br />contaminaced by nuclei returning from the west following the breakup of the <br />blocking tlow regime (7.6% of th~ three-hour blockft). <br />S) Extra-area effects of seeding appear to have occurred over a broad area <br />lyine up to 160 km from the sener_tor aite8. Huch of thia effect occurred as <br />expectad, downwind of the target area. during within~boundl wind conditions. <br />s~ of the effect occurred, not " a_pact.d, ~ell to the welt at tha tSfeet area <br />.. . re.ult of the .aading under blocking flow condition'. Over the downwind <br />,r.. (..g., San Lu~1 Valley) apparent nat increa.ea in precipitation are ...11 <br />in ablolut. value. No net effect appeared It the .bund.ne atatlons in the area <br />to the we.t at the target instrument.d a. pare of the origin.l t.cset .rea. <br />6) Inaufficient data were available 1n the Itable cloud catelory to <br />establish empirically ~here the varm aide li.it (cloud top temperature) of the <br />poaitive effect aeeding windo~ ley. In the unstable catelory the sound ins <br />derived cloud top did not represent th~ true top. The true tops developed <br />fo~lowins the release of instability over the UPWind alope. of the barrieci <br />hence, no assessment of a warm side limit could be investigated for this category. <br />1) Seed ins durins 8 frontal p.aa.ge had no effect other than that accounted <br />fot by the trontally a..octated dl.trlbutlon ot atabillty and wind. <br />8) The overall potential tor precipit,cion enhancement va. assessed in this <br />evaluation study at around 10%, takins into account randomization bias. This <br />translates into an overall streamflow enhancement potential of around 19%. This <br />potenti.l w.. not realized in the seeded 24-hour experimental days for seversl <br />relsona: a) the opportunit1es lost with Jate starts in the tall s~a80n. b) sus- <br />pension.. c) mis,ed forec4sts of .ui~able day., d) lo.ses 1n the accounting for <br />exp.rieental day preclt4tion whon .tron, blocking tlov exi.ted And .eedins vas <br />ineffect{vQ in the torgut nren, e) GMCOS8 accounting in not-seeded days ~h.n <br />contanlination or-curred 0:'1 n not-seeded eMpt:rlmancal d.'lY following a seeded block- <br />inS flow day, f) lonu when colel top s tabla oroAraphtc clouds were seeded under <br />Itrona wind - deep cloud condiLlon~, on~ U) pOsatble modorBte .eeding-ptodueed <br />loases on the uplolinc.l slopes ....hen strong; convection was seeded. <br /> <br />15 <br /> <br />. <br /> <br />A-1l-6 <br />