High Wind in Wyoming, January 8, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MST TUE JAN 8 2002

HIGH WINDS ARE NOTED THIS MORNING IN NW WY IN FOOTHILLS AROUND
CODY...IN CENTRAL WY ALONG CONTINENTAL DIVIDE SOUTH OF WIND RIVER
BASIN AND AROUND CASPER...AS WELL AS THROUGHOUT SE WY...DECENT
SURFACE PRESSURE GRADIENT WITH NORTHWEST FLOW ALOFT HAS SURFACE
WINDS JUST BELOW OR AT WARNING CRITERIA.  CLOUDINESS OVER THE STATE
AT THIS TIME APPEARS TO BE PREDOMINANTLY MID-HI LEVEL WITH SOME LOW
LEVEL CLOUDS AND FOG IN BASINS WHERE INVERSIONS STILL EXIST.  MUCH OF
THE FORECAST AREA WILL AGAIN EXPERIENCE ABOVE NORMAL TEMPERATURES
AS RIDGE AXIS MOVES EASTWARD TODAY FROM GREAT BASIN TO FRONT RANGE IN
ADVANCE OF EAST PACIFIC SYSTEM.

UPPER LEVEL JET EXPECTED TO DROP SOUTHWARD FROM CANADA AND WEAKEN
WITH TIME AS MID LEVEL ATMOSPHERIC ENERGY GETS SPLIT BETWEEN CUT-
OFF LOW OFF BAJA AND SECONDARY SYSTEM IN MID-INTERMOUNTAIN REGION.
WITH SHEAR REGION APPROACHING WY...ANOTHER DISTURBANCE DROPS SOUTH
FROM CANADA ON BACK SIDE OF RIDGE WEDNESDAY NIGHT.  BOTH ETA AND AVN
ARE IN GENERAL AGREEMENT THROUGH FIRST COUPLE OF DAYS...BUT THEN
DIVERGE ON PLACEMENT OF SHORT WAVE TROUGH ENERGY...ETA WANTS
TO CONCENTRATE CUT-OFF AND SECOND SYSTEM IN SW US WHILE AVN KEEPS
CUT-OFF LOW OFF SW COAST WITH SECOND SYSTEM IN CENTRAL UT.  RESULT IS
THAT AVN IS MORE LITTLE MORE GENEROUS ON PRECIPITATION WEDNESDAY TO
THURSDAY...HOWEVER FEEL THAT ETA SOLUTION IS MORE PROBABLE GIVEN THAT
MOST CUT-OFFS LATELY HAVE TRACKED SIMILARLY...ALTHOUGH THERE IS NOT
MUCH SOUTHERN STREAM SUPPORT TO PULL CUT-OFF TO THE EAST AS QUICKLY
AS ETA WANTS TO.  PRECIPITATION THUS SHOULD BE CONCENTRATED IN
WESTERN MOUNTAINS AND VALLEYS AS WELL AS SOUTHERN ZONES...NORTHERN
AND CENTRAL MOUNTAINS WILL GET LIGHT AMOUNTS AND VALLEYS MAY BE
MISSED. WARMER TEMPS WILL BE PUSHED OUT OF THE STATE AS COLDER AIR
AND HIGHER SURFACE PRESSURE FROM CANADA USHERS IN FOLLOWED BY UPPER
LEVEL RIDGE TO TRAP COLD AIR AND MOISTURE IN THE VALLEYS.

IN THE EXTENDED...FORECAST AREA TO BE BRUSHED BY SYSTEM FRIDAY AS
SHORT WAVE TROUGH DROPS DOWN THE BACKSIDE OF THE RIDGE.  HIGH
PRESSURE ONCE AGAIN SETS IN FOR THE WEEKEND AS A NICELY DEVELOPING
SYSTEM BEGINS ITS APPROACH FOR LATE SUNDAY.  THIS SYSTEM APPEARS TO
BE GOOD CANDIDATE FOR NEXT SHOT OF SIGNIFICANT PRECIPITATION FOR
FORECAST AREA SUNDAY NIGHT INTO MONDAY...BUT SPECIFICS ARE STILL
CONTINGENT UPON PLACEMENT OF DYNAMICS AND MOISTURE AS IT INTERACTS
WITH DEEP LOW MOVING THROUGH CENTRAL CANADA.

.RIW...NONE.

MCDONALD