Chris Novy - WA9V <AXVSCCN%UICVMC.bitnet@ugw.utcs.utoronto.ca> (02/12/90)
ZCZC MKCSWODY1 ACUS1 KMKC 121427 MKC AC 121500 Convective Outlook...reference AFOS NMCGPH94O Valid 121500 - 131200Z No severe thunderstorms forecast. General thunderstorms forecast to the right of a line from 30 east-northeast Bellingham, WA..Cascade Locks, OR..Medford, OR..Arcata, CA. Upper low and associated cold air aloft forecast to move south- southeastward into the northwestern states. Moist onshore flow along with middle level cold advection expected to provide sufficient instability for isolated thunderstorms today over western sections of Washington/Oregon and into northwestern California by this evening with thunderstorms threat generally ending by 06Z. Last nights run regional had big surface pressure error east slopes central Rockies and intermountain areas. Pressure as much as 12 millibars lower than progged in eastern Colorado at 12Z. This implies that the rapid eastward shift of the low level jet stream by the Regional likely in error with more surface low per Limited Fine Mesh in central plains. Thus the moisture increase off the western Gulf though initially shallow into south Texas may be more significant than now progged particularly after this forecast period. ..Hales.. 02/12/90 ----------------------------------------------------------------------------- ZCZC NFDQPFHSD FOUS11 KWBC 121414 NMC Heavy Snow Discussion...reference AFOS graphic 93S Valid February 121800 to 130600 Strong short/wave-closed low continuing to drop south-southeastward along B.C. coast. Plenty of cold air cumulus south of system will be moving inland across Washington and Oregon this period. Any onshore flow will be weakening and probably confined to Oregon early in this period..as low level flow through Washington veers to more northerly or northerly direction. With this in mind..heavy snows will be marginal in the higher elevations and almost entirely dependent on the convective nature of the precipitation. Thus..could be some locally heavy snows in the Washington and especially Oregon Cascades..with lighter snows likely in the lower elevations of western Washington and Oregon. Terry --------------------------------------------------------------------------- Chris Novy - WA9V BITNET: axvsccn@uicvmc Southern Illinois Univ. Internet: axvsccn@uicvmc.aiss.uiuc.edu Morris Library - Systems Packet: wa9v@wd9ebq FAX: (618) 453-8109 Carbondale, IL 62901-6632 Phone: (618) 453-1683 or (618) 457-6149 ICBM: 37.43N 89.12W ---------------------------------------------------------------------------