Extreme Cold in Oregon, June 7 to 8, 2002

SOUTHWEST OREGON/NORTHERN CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
230 AM PDT FRI JUN 07 2002

MODELS ARE IN REMARKABLE AGREEMENT WITH TIMING AND LOCATION OUT TO 60
HOURS THIS TONIGHT. MAJOR FORECAST CONCERNS AND CHANGES WILL BE THE
CHANCE OF FROST TO THE EAST OF THE CASCADES...AND WINDS IN THE SHASTA
VALLEY AND THE EAST SIDE THROUGHOUT MUCH OF THE SHORT TERM.

LATE WINTER CONDITIONS MAKE A BRIEF RETURN FRIDAY NIGHT AS NEAR ZONAL
UPPER LEVEL PATTERN GIVES WAY TO A DEEP CLOSED LOW IN THE UPPER GREAT
BASIN. THIS STRONG NORTHERLY FLOW ALOFT WILL BRING VERY UNSEASONABLY
COLD AIR ALOFT TO THE REGION. WITH H85 TEMPS OF NEAR ZERO AND H85 DPS
OF -4 TO -8 FRIDAY NIGHT AND SATURDAY NIGHT. CLEARING OVERNIGHT ON
THE EAST SIDE WILL PROVIDE A BRIEF PERIOD OF DECOUPLING OF THE
WINDS...ALLOWING TEMPERATURES TO DROP QUICKLY THEREAFTER BELOW
FREEZING ACROSS MOST OF THE EAST SIDE ON BOTH NIGHTS. MOISTURE TAKES
A LONG PATH THOUGH WA WITH A SLIGHT ONSHORE FLOW...WITH MOISTURE
ADVECTION LIMITED. THIS HOWEVER WILL BE BALANCED BY A WINTER-LIKE
130KT JET ON THE BACKSIDE OF THIS CLOSED LOW PUTTING THE REGION IN
THE LEFT FRONT QUAD...AND PROVIDING STRONG DYNAMICS TO THE REGION.
WITH LOWERING FREEZING LEVELS...THE CASCADES WILL SEE A DUSTING OF
SNOW AS WELL AS PORTIONS OF THE EAST SIDE.

A STRONG SURFACE GRADIENT AS WELL AS TRANSLATION OF STRONG H7 WINDS
ACROSS THE SHASTA VALLEY WILL CHANNEL STRONG WINDS FROM THE NORTH
THROUGH THE VALLEY AND HAVE INCREASED WINDS THROUGHOUT MUCH OF THE
SHORT TERM IN RESPONSE TO THIS DEVELOPMENT. SVEN

.MFR...GALE WARNING...CAPE BLANCO OR TO POINT ST. GEORGE CA.
       SMALL CRAFT ADVISORY...FLORENCE OR TO CAPE BLANCO OR.