Area Forecast Discussion
Issued by NWS Cheyenne, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KCYS 301155
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
555 AM MDT MON MAR 30 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 402 AM MDT MON MAR 30 2015

A COUPLE OF QUITE MILD/WARM DAYS WILL OCCUR OVER THE CWA TODAY
THROUGH TUESDAY AS AN UPPER RIDGE APPROACHES TODAY THEN SHIFTS
EAST ACROSS THE REGION ON TUESDAY. A WEAK SFC HIGH WILL MOVE INTO
NRN WY TODAY CREATING A WEAK DOWNSLOPE FLOW OVER THE PLAINS WITH
MOSTLY CLEAR SKIES ALLOWING TEMPS TO RISE WELL INTO THE 60S TO
LOWER 70S ACROSS LOWER ELEVATIONS. SIMILAR PATTERN FOR TUESDAY
THOUGH A BIT STRONGER LEE TROUGH SHOULD EXIST OVER THE HIGH
PLAINS. MAX TEMPS SHOULD BE ABOUT 4-7 DEGREES WARMER OVER THE
PLAINS AS A THERMAL RIDGE MOVES ACROSS WITH 700MB TEMPS WARMING TO
ABOUT 5-8C TUESDAY AFTERNOON. MID LEVEL MOISTURE SHOULD BEGIN TO
STEP UP A BIT TUESDAY AFTERNOON AS THE UPPER RIDGE AXIS MOVES EAST
OF THE CWA AND WSW UPPER FLOW SETS UP. MAY SEE A FEW HIGH-BASED
SHOWERS MAINLY AROUND THE MTNS LATER TUESDAY AFTERNOON INTO
TUESDAY NIGHT AS WEAK IMPULSES MOVE BY. PACIFIC FRONT WILL THEN
PASS ACROSS EARLY WEDS AS A DECENT SHORTWAVE SWINGS ACROSS THE
NRN ROCKIES INTO THE NORTHERN PLAINS BY LATE WEDS AFTERNOON WITH
COOLER AND SOMEWHAT BREEZY CONDITIONS FOR WEDS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 402 AM MDT MON MAR 30 2015

THE MAIN FORECAST CONCERN WILL BE THE RETURN OF ACCUMULATING
SNOWFALL GENERALLY SOUTH OF THE NORTH PLATTE RIVER VALLEY THURSDAY
AND THURSDAY NIGHT. A BROAD UPPER-LEVEL TROUGH COMPRISED OF TWO
SHORTWAVES WILL BE IN PLACE ACROSS THE WRN U.S. AND NRN PLAINS
WEDNESDAY NT. THE COLD FRONT ASSOCIATED WITH THE SHORTWAVE OVR THE
NRN PLAINS WILL ALREADY BE WELL SOUTH BY WEDNESDAY NIGHT. THERE WILL
BE LITTLE IF ANY MOISTURE AVAILABLE WEDNESDAY NT WITH PERHAPS JUST A
FEW VERY LIGHT SHOWERS CLOSE TO THE WY/CO STATELINE. THIS INITIAL
FRONT WILL EFFECTIVELY PRIME THE LLVLS IN TIME FOR THE SECOND
SHORTWAVE THAT WILL APPROACH ON THURSDAY AND MOVE OVERHEAD THURSDAY
NT. BOTH THE GFS/ECMWF ARE CONSISTENT IN BREAKING OUT SOME LIGHT
PRECIP ACROSS NRN COLORADO AND AREAS SOUTH OF I80 THURSDAY MORNING.
AS THE TROUGH APPROACHES AS THURSDAY PROGRESSES...MOIST ISENTROPIC
LIFT ATOP THE LLVL UPSLOPE FLOW WILL BE THE CULPRIT FOR PRECIP
BECOMING MORE WIDESPREAD. H7 TEMPS ARE EVEN COLDER THAN EARLIER
RUNS...SO HAVE COOLED HIGHS INTO THE 30S FOR LOCATIONS ABOVE AROUND
5500 FEET ON THURSDAY. SUSPECT THIS WILL BE A REASONABLE CUT-OFF
ELEVATION FOR THE ACCUMULATING SNOW POTENTIAL AS WELL. MOIST
ISENTROPIC LIFT PERSISTS THURSDAY NIGHT BEFORE THE TROUGH DEPARTS
FRIDAY MORNING. AREAS OF LIGHT TO MODERATE ACCUMULATIONS WILL BE
POSSIBLE ABOVE 5500 FEET MAINLY THURSDAY AFTERNOON AND THURSDAY
NIGHT. ALTHOUGH THE TROUGH AXIS DEPARTS ON FRIDAY...THE TRAILING MID-
LEVEL COLD POOL AND ASSOCIATED DAYTIME DESTABILIZATION WILL BE
ENOUGH TO CONTINUE SHOWER CHANCES FRIDAY. TEMPERATURES WILL STILL BE
RELATIVELY COOL ON FRIDAY WITH HIGHS ONLY REACHING THE 40S AT MOST
LOCATIONS.

TEMPERATURES WILL WARM BACK TOWARDS NORMAL ON SATURDAY AND SUNDAY
WITH A BROAD LOW-AMPLITUDE RIDGE YIELDING DRY CONDITIONS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 554 AM MDT MON MAR 30 2015

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. WIND GUSTS OF
15-20 KNOTS CAN BE EXPECTED AT MOST AIRFIELDS 16-01Z.

&&

.FIRE WEATHER...
ISSUED AT 402 AM MDT MON MAR 30 2015

FIRE WEATHER CONCERNS WILL BE AT LEAST ELEVATED OVER PORTIONS OF
THE PLAINS FOR THE NEXT COUPLE OF AFTERNOONS WITH THE HIGHEST
CONCERNS EXPECTED TUESDAY AFTERNOON. MIN REL HUMIDITIES OVER THE
PLAINS WILL FALL TO 10-15% BOTH AFTERNOONS. RIGHT NOW IT APPEARS
WINDS WILL BE GENERALLY BELOW CRITICAL SPEEDS TODAY WHERE FUELS
ARE DRY AS A SURFACE TROUGH DEVELOPS FROM EC WY SOUTHEAST AND SOUTH
OVER FAR EASTERN COLORADO RESULTING IN A MODEST PRESSURE GRADIENT
OVER THE HIGH PLAINS OF SE WY/NEB PANHANDLE THUS HAVE OPTED TO
CANCEL THE FIRE WEATHER WATCH. MAY STILL GET CLOSE OVER A
RELATIVELY SMALL AREA OF FAR SE WY THIS AFTERNOON BUT OVERALL RISK
SEEMS A BIT LESS. NORTHERN PARTS OF THE CWA MAY BE CRITICAL OR
NEAR CRITICAL TUESDAY AFTERNOON AS THE TROUGH DRIFTS A BIT EAST
ALLOWING FOR BREEZIER CONDITIONS THERE. CONCERNS THEN WANE WEDS
AS COOLER AIR BEGINS TO ARRIVE BEHIND A COLD FRONT.

&&

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

&&

$$

SHORT TERM...RE
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...RE



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.