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FXUS65 KCYS 071106
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MST SAT NOV 7 2009
SHORT TERM
GENERALLY MILD AND MAINLY DRY WEATHER EXPECTED ACROSS THE CWA DURING
THE PERIOD. VARYING AMOUNTS OF MAINLY HIGH CLOUDS EXPECTED AS
DECENT HIGH LEVEL MOISTURE CONTINUES ACROSS THE REGION ON WSW UPPER
FLOW WITH SOME LEE ENHANCEMENT...EVIDENT NOW OVER FAR SE WY INTO THE
NEB PANHANDLE. LESS WIND TODAY WITH MODEST SFC TROF DEVELOPING
ALONG THE MTNS. SHORTWAVE ENERGY MOVING ACROSS THE NORTHERN ROCKYS
LATER TODAY AND TONIGHT WILL PUSH A PACIFIC COOL FRONT ACROSS THE
CWA OVERNIGHT WITH MAXS SUNDAY ABOUT 5-8 DEGREES LESS THAN TODAY.
RATHER DRY AIR MASS WILL HINDER PCPN WITH LATEST NAM SHOWING ONLY A
BIT OF LIGHT PCPN OVER THE HIGHER MTNS LATER TONIGHT.
LONG TERM
AN UPPER LEVEL SHORTWAVE WILL IMPACT THE AREA ON SUNDAY NIGHT INTO
MONDAY MORNING. BOTH THE ECMWF AND GFS INDICATE PRECIPITATION
EXTENDING FROM THE SIERRA MADRE MOUNTAIN RANGE EASTWARD THROUGH
THE SOUTHERN NEBRASKA PANHANDLE BY ON MONDAY MORNING. THERE WILL
BE SNOW IN THE HIGHER TERRAIN...BUT LITTLE ACCUMULATION. ALL
MEMBERS FROM THE SREF FORECAST FOR SCOTTSBLUFF INDICATE THE
PRECIPITATION TYPE AS RAIN. THUS ANTICIPATE THERE WILL BE SNOW AND
RAIN MIX EARLY IN THE MORNING ACROSS LARAMIE COUNTY WITH RAIN
FURTHER EAST. THROUGH MONDAY MORNING RAIN AND SNOW MIX WILL
TRANSITION INTO RAIN. EXPECT SHOWERS TO DIMINISH THROUGH THE LATE
MORNING. TEMPERATURES WILL BE COOLER WITH HIGHS IN THE UPPER 40S
TO LOWER 50S ON MONDAY.
HIGH PRESSURE WILL REGAIN STRENGTH ON TUESDAY AND WEDNESDAY WITH
HIGH TEMPERATURES REBOUNDING INTO THE UPPER 50S AND LOWER 60S. 500
MB HEIGHT ANOMALIES FROM THE GEFS INDICATE AROUND ONE STANDARD
DEVIATION WARMER THAN THE CLIMATOLOGY FOR TUESDAY AND WEDNESDAY.
THUS EXPECT DRY CONDITIONS THROUGH MID WEEK. MODELS TEND TO DIFFER
BY MID WEEK WITH THE GEM MODEL INDICATING A CLOSED OFF UPPER LEVEL
LOW OFF THE WEST COAST AND THE GFS AND ECMWF INDICATING OPEN WAVE
TROUGHS. BOTH THE GFS AND ECMWF HAVE TIMING ISSUES AS WELL.
LOOKING AT THE GFS ENSEMBLE FORECAST SYSTEM SHOWS A VARIETY OF
MODEL SOLUTIONS AMONG THE MEMBERS IN DEVELOPING THIS UPPER LEVEL
SYSTEM ON THURSDAY INTO NEXT WEEKEND. THE GFS 00Z MODEL RUN
COMPLETELY DIFFERS IN THE QPF AMOUNT ACROSS THE AREA COMPARED TO
THE LATEST 06Z RUN. ALSO THE ECMWF INDICATES SOME QPF BUT NOT SURE
IF THE WARRANTED HIGHER POPS IN THE CURRENT FORECAST. THUS
HAVE DROPPED THE POPS MORE IN LINE WITH THE CLIMATOLOGICAL POPS
FOR THE AREA GIVEN THE UNCERTAINTY. AT THIS TIME...CERTAINLY DO
NOT WANT TO EVEN CONSIDER THE SNOW VERSUS RAIN ISSUES WITH THE
SYSTEM NEXT WEEK.
AVIATION
VFR CONDITIONS EXPECTED ACROSS THE AREA THOUGH SUNDAY.
SFC COOL FRONT WILL PASS ACROSS TONIGHT WITH A FEW MTNS SNOW SHOWERS
POSSIBLE LATE TONIGHT/EARLY SUNDAY.
FIRE WEATHER
NO CONCERNS SEEN WITH LESS WIND AND COOLER
TEMPERATURES THROUGH SUNDAY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM/AVIATION...RE
LONG TERM...MAK
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