Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 050947
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
347 AM MDT SAT SEP 5 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 303 AM MDT SAT SEP 5 2015

PREDAWN WATER VAPOR IMAGERY DEPICTED A UPPER TROUGH OVER THE
NORTHWEST CONUS WITH A LOW CENTERED OVER OR. A LARGE UPPER RIDGE
ENCOMPASSED THE EASTERN 2/3 OF THE NATION. SUBTROPICAL/MONSOON
MOISTURE CONTINUED TO STREAM NORTHEAST FROM BAJA CA INTO THE
ROCKIES AND HIGH PLAINS. A PASSING WEAK SHORT WAVE OVER FAR
SOUTHEAST WY AND WESTERN NE PRODUCED SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS. THIS ACTIVITY WILL END BY DAYBREAK. SKIES
WERE MOSTLY CLOUDY WITH LIGHT WINDS AND TEMPERATURES IN THE 50S
AND 60S.

THE SHORT RANGE MODELS HAVE MAINTAINED THEIR RUN-TO-RUN CONSISTENCY
FOR SEVERAL DAYS PROGGING THE PACIFIC NORTHWEST UPPER LOW TO LIFT
NORTHEAST THROUGH ID AND MT DURING THE NEXT 24 HOURS. THE MOIST
SOUTHWEST FLOW ALOFT WILL PROVIDE CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON AND
EVENING...ESPECIALLY WEST OF I-25. GUSTY WINDS UP TO 45 MPH...
LIGHTNING AND BRIEF MODERATE TO HEAVY RAIN WILL BE THE PRIMARY
HAZARDS. OUTSIDE OF THE CONVECTION...SOUTHWEST WINDS WILL GUST TO
35 MPH WEST OF THE LARAMIE RANGE. IT WILL BE ANOTHER WARM AFTERNOON
FOR THE PLAINS WITH HIGHS IN THE 80S TO AROUND 90.

A PACIFIC COLD FRONT IS FORECAST TO MOVE EAST ACROSS THE CWA LATE
TONIGHT AND EARLY SUNDAY MORNING...USHERING IN A DRIER AND MORE
STABLE AIR MASS. WEST TO NORTHWEST WINDS WILL INCREASE TO 25 TO
35 MPH BEHIND THE FRONT SUNDAY MORNING...WITH HIGHER GUSTS
POSSIBLE IN WIND PRONE AREAS OF SOUTHEAST WY. SUNDAY WILL BE 5 TO
10 DEGREES COOLER WITH HIGHS IN THE 70S TO LOWER 80S.

MONDAY WILL BE A PLEASANT DAY WITH NEAR SEASONABLE TEMPERATURES. A
WEAK SURFACE TROUGH IS PROGGED BY MOST OF THE MODELS TO SET UP NEAR
THE WY-NE BORDER MONDAY WITH A FEW SHOWERS OR THUNDERSTORMS POSSIBLE
OVER THE FAR SOUTHEAST PART OF THE CWA...ROUGHLY EAST OF A ALLIANCE
TO SIDNEY LINE. BREEZY WEST WINDS WILL DEVELOP ALONG AND WEST OF
THE LARAMIE RANGE MONDAY AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT SEP 5 2015

A LOW AMPLITUDE CYCLONIC UPPER FLOW SHOULD EXIST OVER SRN CANADA
AND THE NORTHERN TIER STATES MOST OF NEXT WEEK. SEVERAL UPPER
SHORT WAVES WILL TRANSLATE EAST ACROSS THE REGION IN THIS FLOW
PATTERN BRINGING SURGES OF COOLER AIR. ONE MINOR FRONT WILL SCOOT
ACROSS MONDAY NIGHT BUT HAVE LITTLE EFFECT ON THE SENSIBLE WEATHER
ACROSS THE CWA WITH WARM AND DRY WEATHER EXPECTED FOR TUESDAY AND
WEDS. A LITTLE STRONGER FRONT LOOKS TO PASS ACROSS LATER WEDS BUT
AGAIN LOOKS DRY. MILD TEMPS THURSDAY THEN A STRONGER SHORTWAVE
WILL MOVE SOUTHEAST OUT OF SOUTHERN CANADA INTO THE PLAINS THURSDAY
NIGHT DRIVING YET ANOTHER PUSH OF COOLER AIR SOUTH OUT OF CANADA
AND REINFORCING THE MILD AIR MASS OVER THE REGION. THIS SYSTEM MAY
BRING A FEW SHOWERS TO MAINLY THE PANHANDLE FRIDAY IN ASSOCIATION
WITH THE PASSING OF THE SHORT WAVE...THOUGH BETTER ENERGY SHOULD
PASS TO THE EAST OF THE AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 300 AM MDT SAT SEP 5 2015

VFR EXPECTED OVER ALL TERMINALS THROUGH THE PERIOD. ISOLATED
SHOWERS AND TSTMS SHOULD DEVELOP OVER PARTS OF THE AREA THIS
AFTERNOON THEN DISSIPATE THIS EVENING. SURFACE COLD FRONT WILL
PASS ACROSS THE AREA LATER TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT SEP 5 2015

MOIST SOUTHWEST FLOW ALOFT WILL PRODUCE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO MOST OF THE FORECAST AREA THIS AFTERNOON
AND EVENING. THERE IS A LOW RISK OF DRY LIGHTNING. CRITICAL FIRE
WEATHER CONDITIONS WILL DEVELOP SUNDAY FOLLOWING THE PASSAGE OF A
COLD FRONT. WESTERLY WINDS WITH FREQUENT GUSTS OF 30 TO 40 MPH ARE
EXPECTED. DESPITE THE COOLER TEMPERATURES...RELATIVE HUMIDITIES
WILL FALL TO 10 TO 15 PERCENT SUNDAY AFTERNOON OVER PORTIONS OF
EAST AND SOUTH CENTRAL WYOMING.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM LATE SUNDAY MORNING THROUGH EARLY
     SUNDAY EVENING FOR WYZ301>303-308.

NE...NONE.
&&

$$

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



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