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~rre~ s~cb:e a~r aDDroaches a~ orographic barrier, it is cor.~on for a "=O'.l:l:'~:'!l-p2:-2:::"le~" jet to form a:: low levels. Schwerdtfeger (1975) ?~Q~Qsed t~at t2E barriey jet was a ~esosc2~e phenomenon. His explanation ~~~ ~~2; ~he3 :arge-scale s::able a~r was forced te rise over c mouatain C2~r~e~, the forced asce~t resultej i~ s~gnifica~: decelera::ion of the 'rda%~i[':.g " un ~~ lr:e -. - ~c~~~er ~crLa~ co~pc~ent. ef the sta~le air results in a ~:-ess~re excess on tte ~~wind barrier. Godske et a~. (1975) discussed s~c~ a~ Gra~r2DnlC press~re excess and Smith (1982) calculated similar p=ess~re excesses usin~ ccaly~ical models. Parish (1982) nu~erically D2rrier jet over the u~wi~G slope of the Sierra si~~la~ed barrier ~~ing ~ 2-D (XZ) ~oce~ whic~ included the Ccriolis ter~. i~e deceleration or t~e ba:-rier ~orwal component at low levels and the Coriolis effect resJl:s in :.ae ~O~ :evel barrier je:. Sicil2rily, cne may explain the barrier jec bv the ther~al wind eQUati8TI. Ha~witz (1983) p~esen:ed a case s~udy of stabie airflow during a s~or~ iE ~hich he i~fer~ec 2 press~~e excess of 3 ~b fer a 1 km ceep QaC ~3~:~er~3~ ~e.e~ near :te barrler. The deep isother~al lever resulted fro~ orocess c: ~e~t~ng. ~ar~~tz ffieasured -. ~ . ----,.......-- ;J, _Cl!..le. _..:..t- the barrier normal co=pOlle~L 0: ~low by sca~~i~g nCTllial to the barrier in aG aEI ~ode with a ~o::j'Dle!" raGar. The a~rflc~ ~ithin the deep isothermal layer was stable a~d, ~~ererore, sigh~fica~tly decelerated. 7he pressure excess was deduced 1;:0 be .prese~t O~ the barrier beGeath the deep isothermal layer. (~\.1. "CC{"~; 0,,') pert pepe~ Maywi~z (1987 a and b) described anc expleined l~ 2 +-.. -,.... ,-W0 ~~eci?i:~t~8~ p~ocesses d~ring rWQ dee?t orographic storms. ....- --; ..-,.- c_~_~...;"" C~e ~as ve~v st~b:e an~ the secoGc storI was slig~tly stable. Each ot ... v b.. J i I " y I I I I I I I I l , .. I I .. ~ f I j I I I I ! i t:1e