Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 041002
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
402 AM MDT SAT JUL 4 2015

.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 403 AM MDT SAT JUL 4 2015

FORCING DUE TO WARM AIR ADVECTION ALONG AN ELEVATED WARM FRONT
IS THE MAIN FACTOR IN ISOLATED SHOWER ACTIVITY WHICH ARE OCCURRING
EARLY THIS MORNING. THIS ACTIVITY MAY LINGER THROUGH AROUND
SUNRISE BEFORE DYING OFF COMPLETELY.

FOLLOWING THE PASSAGE OF THE WARM FRONT...TEMPERATURES WILL RISE
TO SOME OF THE HIGHEST READINGS OF THE YEAR...MAKING FOR A VERY
WARM 4TH OF JULY. HIGH TEMPERATURES WILL REACH THE MID 80S TO MID
90S OVER MOST OF THE AREA OUTSIDE OF THE MOUNTAINS.

AMPLE SUNSHINE WILL PUSH TEMPERATURES TO NEAR CONVECTIVE
INITIATION THIS AFTERNOON. THERE ARE NO STRONG FORCING MECHANISMS
IN PLACE TODAY AND THAT BEING THE CASE IT IS TOUGH TO PINPOINT
WHERE THUNDERSTORMS WILL FOR CERTAIN DEVELOP. THEREFORE HAVE A
SLIGHT CHANCE IN PLACE ACROSS THE ENTIRE FORECAST AREA TODAY.
THUNDERSTORMS THAT DEVELOP THIS AFTERNOON/EVENING WILL HAVE THE
POTENTIAL TO BECOME SEVERE MAINLY OVER EASTERN PORTIONS OF THE
FORECAST AREA. MODELS ARE INDICATING UPWARDS OF 2000 J/KG MU CAPE
INTO THE NEBRASKA PANHANDLE. THIS IS ALSO WHERE THERE SHOULD LOW
LEVEL SPEED CONVERGENCE FROM SOUTHERLY WINDS ALONG WITH A 50-60
KT UPPER LEVEL JET WHICH COULD AID IN THUNDERSTORMS DEVELOPMENT
AND STRENGTH OF ANY STORMS THAT MIGHT DEVELOP.

COLD FRONT STILL ON SCHEDULE TO MOVE ACROSS THE AREA LATE SUNDAY
WITH ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. EXACT TIMING OF
THE FRONT IS STILL SOMEWHAT OF A QUESTION WHICH COULD HAVE A
SIGNIFICANT IMPACT ON HIGH TEMPERATURES SUNDAY. AT THIS TIME
THINKING THE FRONT WILL MOVE INTO THE NORTHERN CWA AROUND NOON AND
MOVE ACROSS THE REST OF THE FORECAST AREA BY LATE AFTERNOON/EARLY
EVENING. THIS MEANS SUNDAY SHOULD BE ANOTHER VERY WARM DAY ACROSS
MOST OF THE FORECAST AREA. CLOUD COVER IN THE WEST AND NORTH
SHOULD HOLD TEMPERATURES DOWN PRECEDING THE COLD FRONT. A FEW
STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE SUNDAY AFTERNOON.

COOLER MONDAY WITH LESSER CHANCES FOR SHOWERS AND THUNDERSTORMS.
EAST OF THE LARAMIE RANGE THE AIRMASS WILL LIKELY REMAIN STABLE
THROUGH THE AFTERNOON WITH LIGHT UPSLOPE WINDS AND AMPLE LOW LEVEL
CLOUD COVER. TO THE WEST OF THE LARAMIE RANGE THERE IS AT LEAST A
CHANCE FOR MEASURABLE PRECIPITATION.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM MDT SAT JUL 4 2015

MEDIUM TO LONG RANGE MODELS SHOW A CONTINUATION OF THE UNSETTLED
WEATHER PATTERN INTO THE MIDDLE PART OF NEXT WEEK. THERE IS SOME
POTENTIAL OF CONDITIONS DRYING A BIT BY LATE THIS WEEK...BUT GIVEN
RECENT MODEL TRENDS OF UNDER ESTIMATING BL MOISTURE...NOT VERY
CONFIDENT WITH THIS SOLUTION AT THIS TIME.

MONDAY AND MONDAY NIGHT WILL BE MUCH COOLER BEHIND A RELATIVELY
STRONG COLD FRONT FOR THIS TIME OF THE YEAR. LOW TEMPERATURES MAY
DROP INTO THE 40S TO LOW 50S ACROSS MANY AREAS...ESPECIALLY OVER
SOUTHEAST WYOMING. FOR TUESDAY MODELS SHOW THE MID TO UPPER LEVEL
FLOW BECOMING MORE WESTERLY...ALTHOUGH LLVL WINDS WILL BE SOUTH OR
SOUTHEAST. HIGH TEMPERATURES WILL LIKELY REBOUND TUESDAY...BUT
WITH PW/S OVER 1 INCH ACROSS MOST OF THE HIGH PLAINS...ANOTHER
ROUND OF SHOWERS AND TSTORMS ARE EXPECTED. WITH ANOTHER SHORTWAVE
TROUGH DIVING SOUTHWARD ACROSS THE NORTHERN ROCKY
MOUNTAINS...SHOWER ACTIVITY MAY LINGER THROUGH TUESDAY NIGHT AS
WELL. WEDNESDAY WILL BE SIMILAR AS ANOTHER COLD FRONT MOVES
SOUTHWARD AND STALLS ALONG THE FRONT RANGE. THERE IS A DECENT
CHANCE OF STRONG TO SEVERE STORMS BOTH DAYS DUE TO A COMBINATION
OF COOL AIR ALOFT PUSHING INTO THE AREA...AMPLE MOISTURE...AND
FAVORABLE 0-6KM SHEAR PROFILES ACROSS THE HIGH PLAINS. INCREASED
POP BETWEEN 40 TO 60 PERCENT BY WEDNESDAY AFTERNOON WITH A GOOD
CHANCE OF MODERATE TO HIGH RAINFALL AMOUNTS OVER PORTIONS OF
SOUTHEAST WYOMING.

FOR LATE NEXT WEEK...MODELS INDICATE AN UPPER LEVEL LOW AROUND
CENTRAL CALIFORNIA AS A RIDGE OF HIGH PRESSURE BEGINS TO BUILD
OVER THE SOUTHERN ROCKY MOUNTAINS. GFS SHOWS AN UPPER LEVEL HIGH
CENTERED AROUND TEXAS WITH THE CALIFORNIA UPPER LOW SLIDING
EASTWARD BY FRIDAY. MODELS ARE HINTING TO MONSOON MOISTURE
INCREASING AND PUSHING NORTH BETWEEN THESE TWO FEATURES. EXPECT A
FEW DRIER DAYS FOR SOUTHEAST WYOMING AND WESTER NEBRASKA...BUT
THIS MAY BE SHORT-LIVED AS MONSOON MOISTURE ADVECTS NORTHWARD INTO
COLORADO AND WYOMING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH SATURDAY NIGHT)

VFR CONDITIONS WILL PREVAIL WITH SOME ISOLATED RAIN SHOWERS ACROSS
THE HIGH PLAINS EARLY THIS MORNING. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED THIS AFTERNOON BUT SHOULD BE ISOLATED
IN COVERAGE SIMILAR TO YESTERDAY. BRIEF MVFR VIS ARE POSSIBLE WITH
ANY THUNDERSTORMS WITH ERRATIC GUSTY WINDS.

&&

.FIRE WEATHER...
ISSUED AT 323 AM MDT SAT JUL 4 2015

WARM TEMPERATURES WILL BE IN PLACE TODAY ALONG WITH ISOLATED
THUNDERSTORMS OVER SOUTHEAST WYOMING AND WESTERN NEBRAKSA
PANHANDLE. STRONG ERRATIC WIND GUSTS WILL BE POSSIBLE WITH ANY
THUNDERSTORMS AND LARGE HAIL WILL ALSO BE POSSIBILITY. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE SUNDAY. SHOWERS AND
THUNDERSTORMS ARE LIKELY TO BRING WETTING RAINS TO MOST OF THE
AREA LATE SUNDAY INTO SUNDAY NIGHT. COOLER TEMPERATURES FOR MONDAY
WITH THE MAIN CHANCES FOR PRECIPITATION ALONG AND WEST OF THE
LARAMIE RANGE. CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WILL CONTINUE THROUGH NEXT WEEK.

&&

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

&&

$$

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


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