[list.storm-l] Severe Weather Outlook & Heavy Snow Discussion

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
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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
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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
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