458 
FXUS65 KCYS 071001
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
300 AM MST SAT FEB 7 2004

.SHORT TERM...UPPER RIDGE AXIS OVER WESTERN WYOMING EARLY THIS 
MORNING MOVES TO THE EASTERN WYOMING BORDER BY 00Z. HIGH CLOUDS 
ALREADY SPREADING INTO THE WEST AHEAD OF NEXT SYSTEM. MODELS SIMILAR 
WITH RESPECT TO TIMING AND STRENGTH OF FEATURES THROUGH THE SHORT 
TERM PERIOD. WILL CONTINUE IDEA OF SCATTERED POPS SPREADING INTO THE 
WESTERN CWA THIS AFTERNOON DUE TO OROGRAPHIC LIFT. MODELS AGAIN THIS 
RUN ARE SHOWING TENDENCY TO WARM TEMPERATURES TOO MUCH TODAY. GIVEN 
THE INCREASE IN CLOUD COVER...SNOW COVER...SOUTHERLY WINDS ON THE 
WYOMING PLAINS AND COLD START TO THE DAY IN THE PANHANDLE...WILL 
KEEP HIGHS BELOW GUIDANCE NUMBERS. SURFACE COLD FRONT MOVES SOUTH 
THROUGH THE AREA BY 06Z SUNDAY WITH UPSLOPE FLOW AND INCREASING LOW 
LEVEL MOISTURE COMBINING TO PRODUCE LIGHT SNOW ACROSS MUCH OF THE 
WYOMING PORTION OF THE CWA BY 12Z SUNDAY. PREFER THE MESOETA 
DEPICTION OF THE QPF SCENARIO WITH WESTERN NEBRASKA PANHANDLE 
STAYING OUT OF THE PRECIPITATION THROUGH 12Z HOWEVER.

.LONG TERM...IMPRESSIVE S/WV TROF MOVES INTO WRN NEB/WRN KS BY 
18Z/SUN. BOTH ETA/GFS SHOW DECENT OMEGA/MOISTURE SO WILL GO WITH 
HIGH POPS IN THE MORNING...ESPECIALLY FAR SERN WY/WRN NEB ZONES. 
SUN AFTERNOON...DYNAMICS WANE BUT WITH CAA AND CYCLONIC FLOW ALOFT 
WILL MAINTAIN CHANCE SNOW WHICH MATCHES WELL WITH SURROUNDING ZONES. 
FOR SUNDAY NIGHT...WILL DECREASE SNOW CHANCES AS MOISTURE/DYNAMICS 
ARE LIMITED...DESPITE CYCLONIC FLOW ALOFT. COLD AIR REMAINS 
ENTRENCHED ON MON AS DEEP CYCLONIC FLOW ALOFT CONTINUES. POPS LOW 
DUE TO LIMITED MOISTURE/DYNAMICS. ANOTHER WEAK S/WV TROF AFFECTS WY 
ON TUE...GFS LOOKS OVERDONE ON CLOUDS/POPS WHILE ETA UNDERDONE. WILL 
COMPROMISE WITH SLIGHT CHANCE/CHANCE POPS WHICH MATCHES WELL WITH 
RIW/UNR GRIDS. GFS STRONGER WITH WED S/WV TROF THAN ITS PREVIOUS 
RUN. HOWEVER...EVEN NORMALLY PESSIMISTIC GFS SHOWS LIMITED 
MOISTURE/DYNAMICS SO WILL KEEP IT DRY ON WED. DRY NLY FLOW ALOFT 
PREVAILS THU. FLOW ALOFT BACKS TO NWLY ON FRI WHICH WILL INDUCE A 
DECENT WARMUP ACCORDING TO GFS PROGGED 850 MB TEMPS. IN 
GENERAL...GUIDANCE LOWS/HIGHS THRU PD LOOK REASONABLE WITH MINOR 
TWEAKING.   

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

STARK/RUBIN