Area Forecast Discussion
Issued by NWS Cheyenne, WY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 040907
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
307 AM MDT FRI SEP 4 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 300 AM MDT FRI SEP 4 2015

CURRENT IR SATELLITE LOOP SHOWS THE UPPER LEVEL
DISTURBANCE...WHICH BROUGHT SCATTERED SHOWERS TO THE EASTERN HALF
OF THE FORECAST AREA LAST NIGHT...LIFTING NORTHEAST INTO CENTRAL
NEBRASKA AND THE DAKOTAS EARLY THIS MORNING. SKIES HAVE CLEARED
BEHIND THE DISTURBANCE DUE TO DRIER WESTERLY FLOW AND A MORE
STABLE ATMOSPHERE. TODAY WILL BE PRETTY SIMILAR TO THURSDAY WITH
HIGH TEMPERATURES IN THE 80S ACROSS SOUTHEAST WYOMING AND LOW TO
MID 90S OVER WESTERN NEBRASKA. LLVL INSTABILITY AND JET DYNAMICS
DO NOT LOOK AS GOOD AS THEY DID 24 HOURS AGO WITH CURRENT MODELS
SHOWING THE NEXT UPPER LEVEL DISTURBANCE MUCH FURTHER SOUTH
COMPARED TO YESTERDAY...BUT CAN NOT RULE OUT SOME ISOLATED
THUNDERSTORMS ALONG WITH BANDS OF RAIN SHOWERS DEVELOPING OVER THE
MOUNTAINS. THIS ACTIVITY MAY OCCUR LATER IN THE DAY AS THIS
DISTURBANCE WILL BE SLOW TO LIFT NORTHWARD INTO THE FORECAST AREA.
KEPT POP BETWEEN 40 TO 60 PERCENT IN THE MOUNTAINS...BUT LOWERED
PRECIP CHANCES A BIT OVER THE HIGH PLAINS.

FOR THIS WEEKEND...THE MAIN UPPER LEVEL TROUGH OVER THE PACIFIC
NORTHWEST WILL MOVE INTO MONTANA ON SATURDAY AS THE COLD FRONT
EXTENTS SOUTHWARD ACROSS WESTERN WYOMING. IT WILL BE SLIGHTLY
COOLER WITH HIGHS IN THE UPPER 70S TO UPPER 80S. THE MAIN STORM
SYSTEM IS STILL EXPECTED TO PRIMARILY IMPACT IDAHO AND MONTANA
WITH SOME MUCH NEEDED RAINFALL OVER THOSE AREAS. KEPT A SLIGHT
CHANCE OF THUNDERSTORMS WITH SOME RAIN SHOWER ACTIVITY OVER
SOUTHEAST WYOMING...MAINLY DUE TO AN INTENSIFYING JET ALOFT. THIS
100 KNOT JET WILL BE OVER THE FORECAST AREA ON SUNDAY AS THE
SURFACE COLD FRONT MOVES THROUGH THE AREA. HIGH TEMPERATURES WILL
BE 5 TO 10 DEGREES COOLER COMPARED TO SATURDAY WITH HIGHS IN THE
UPPER 60S ACROSS CARBON COUNTY...TO THE LOW TO MID 80S ACROSS
WESTERN NEBRASKA. IT WILL BE QUITE WINDY AS WELL...EVEN THOUGH THE
NAM AND GFS ARE 5 TO 8 KNOTS WEAKER WITH WIND SPEEDS COMPARED TO
YESTERDAY. STILL...GUSTS UP TO 40 MPH ARE POSSIBLE NORTH OF I80.
MOST OF THE AREA WILL BE DRY AS PW/S LOWER TOWARDS ONE QUARTER
INCH. WILL HAVE TO WATCH THE SOUTHEAST PORTION OF THE AREA ALONG
I80...THE GFS AND GEM SHOW JET DYNAMICS ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THE JET PRODUCING SOME CONVECTION SOUTH OF A
LINE FROM LARAMIE TO ALLIANCE NEBRASKA.


.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY...

PRETTY QUIET FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.  A WEAK AND
BROAD UPPER TROUGH IS PROGGED ACROSS THE NORTHERN INTERMOUNTAIN WEST
ON MONDAY.  MOISTURE AND INSTABILITY IS LIMITED SO STORM CHANCES
WILL BE QUITE LOW.  THE EXCEPTION COULD BE FOR AREAS RIGHT ALONG THE
COLORADO BORDER BY MON EVENING AS A WEAK FRONT RESULTS IN
CONVERGENCE THERE.  THE MODELS HAVE COME IN A BIT COOLER AND MORE
MOIST FOR TUES AND TUES NIGHT.  THE GFS STILL SHOWS A MORE DEFINED
SHORTWAVE MOVING EASTWARD OVER WY ON TUES NIGHT....RESULTING IN A
WIDESPREAD LIGHT QPF EVENT ACROSS THE REGION.  THE ECMWF INDICATES
LESS AMPLIFICATION WITH THE UPPER WAVE AND IS MUCH DRIER.  CURRENTLY
HAVE SLIGHT CHANCE POPS FOR TUES NIGHT AND WED MORNING.  IT WILL
FEEL MORE LIKE FALL ON TUES/WED ESPECIALLY AT NIGHT WHEN LOWS FALL
INTO THE 40S.  TEMPS WILL START TO MODERATE SOME BY THURS WITH A DRY
NORTHWESTERLY FLOW ALOFT IN PLACE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1142 PM MDT THU SEP 3 2015

ISOLATED SHOWERS AND A BKN LAYER OF CLOUDS WITH BASES AROUND 10000
FT WILL CONTINUE TO AFFECT PORTIONS OF THE NEBRASKA PANHANDLE
FOR THE NEXT FEW HOURS. MOSTLY CLEAR SKIES WILL THEN OCCUR THROUGH
THE REMAINDER OF THE NIGHT. ISOLATED SHOWERS AND THUNDERSTORMS
WILL DEVELOP OVER AREAS TO THE WEST OF THE LARAMIE RANGE BY FRI
AFTN.

&&

.FIRE WEATHER...
ISSUED AT 213 AM MDT FRI SEP 4 2015

CONCERNS WILL INCREASE THROUGH THIS WEEKEND WITH SIGNIFICANT FIRE
WEATHER CONCERNS ANTICIPATED ON SUNDAY. A FIRE WEATHER WATCH WILL
LIKELY BE ISSUED FOR SUNDAY AFTERNOON AND EVENING AS RELATIVE
HUMIDITIES LOWER DOWN TO 10 PERCENT BEHIND A COLD FRONT AND UPPER
LEVEL TROUGH. WINDY CONDITIONS ARE ALSO EXPECTED ACROSS A GOOD
PORTION OF THE AREA...EVEN THOUGH MODELS ARE TRENDING A LITTLE BIT
LOWER ON WINDS FOR SUNDAY. EITHER WAY...RELATIVE HUMIDITIES DOWN
TO 10 PERCENT AND GUSTS AROUND 35 MPH WILL CREATE HAZARDOUS FIRE
WEATHER CONDITIONS FOR PORTIONS OF THE FORECAST AREA. EAST CENTRAL
WYOMING AND THE NORTHERN NEBRASKA PANHANDLE...INCLUDING ZONES 311
AND 312...APPEAR THE MOST LIKELY TO REACH CRITERIA.

&&

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

$$

SHORT TERM...TJT
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...TJT


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