Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 241010
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
410 AM MDT FRI APR 24 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT FRI APR 24 2015

SHOWERS AND THUNDERSTORMS WILL AGAIN DEVELOP ACROSS THE AREA
TODAY. SEVERE THUNDERSTORMS ARE NOT EXPECTED TODAY BUT GUSTY WINDS
AND SMALL HAIL WILL BE POSSIBLE MAINLY OVER THE NEBRASKA PANHANDLE
THIS AFTERNOON. LOOKING AT 0-3 KM CAPE AND LOW LEVEL LAPSE
RATES...WOULD NOT BE SURPRISED TO SEE A FEW FUNNEL REPORTS INTO
THE NORTHERN NEBRASKA PANHANDLE AND INTO NIOBRARA COUNTY THIS
AFTERNOON WITH ANY DEVELOPING SHOWERS AND THUNDERSTORMS. THIS
AREA WILL BE NEAR AN UPPER LEVEL CIRCULATION AND SURFACE BOUNDARY
SUCH THAT A BRIEF LANDSPOUT IS A REMOTE POSSIBILITY.

A SHORTWAVE RIDGE WILL MOVE ACROSS THE AREA TONIGHT GENERALLY
BRINGING AN END TO CONVECTIVE ACTIVITY BUT SHOWERS AND
THUNDERSTORMS WILL AGAIN DEVELOP SATURDAY AFTERNOON AS AN UPPER
LEVEL LOW SHIFTS FROM THE PACIFIC NORTHWEST INTO THE FOUR CORNERS
REGION. SEVERE THUNDERSTORMS AREA AGAIN UNLIKELY SATURDAY.
PRECIPITATION WILL INCREASE IN COVERAGE SATURDAY NIGHT WITH SNOW
ACCUMULATIONS EXPECTED INTO THE MOUNTAINS. LIKE LAST WEEKS
SYSTEM...PRECIPITATION TYPE IS A BIG QUESTION. TEMPERATURES ALOFT
LOOK TO BE WARM ENOUGH FOR MAINLY RAIN OUTSIDE OF THE
MOUNTAINS...OF COURSE THE MAIN QUESTION WILL BE PRECIPITATION TYPE
OVER THE HIGHER ELEVATION OF SOUTHEAST WYOMING OUTSIDE OF THE
MOUNTAINS. PLACES LIKE LARAMIE AND CHEYENNE WILL AGAIN BE
BORDERLINE BETWEEN RAIN AND SNOW. WILL HAVE TO KEEP A CLOSE EYE ON
MODEL TEMPERATURE TRENDS OVER THE NEXT 24 HOURS AS A FEW DEGREES
WARMER OR COOLER WILL MAKE A HUGE DIFFERENCE IN PRECIPITATION TYPE
AND THE POTENTIAL FOR SNOW. SIGNIFICANT SNOWFALL CAN NOT BE RULED
OUT JUST QUITE YET FOR SATURDAY NIGHT THROUGH SUNDAY
NIGHT...ESPECIALLY CONSIDERING THE MODLES TYPICALLY STRUGGLE WITH
MANY ASPECTS OF CLOSED/NEARLY CUTOFF UPPER LOWS...NOT THE LEAST
BEING PLACEMENT AND TIMING OF UPPER LEVEL FEATURES.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 330 AM MDT FRI APR 24 2015

MAIN FORECAST CONCERN FOR THE LONG RANGE WILL CONTINUE BE THE
UPPER LEVEL LOW MOVING EASTWARD ACROSS THE CENTRAL/SOUTHERN ROCKY
MOUNTAINS LATE SUNDAY AND INTO THE SOUTHERN GREAT PLAINS BY
MONDAY. THE NORTHERN PORTION OF THIS SYSTEM MAY RESULT IN
LINGERING PRECIPITATION INTO TUESDAY. OTHERWISE...EXPECT THE
PRECIPITATION INTENSITY TO GRADUALLY DIMINISH INTO MONDAY. THE GFS
IS THE WARMEST...SHOWING SNOW LEVELS ABOVE 8000 FEET THROUGH
MONDAY. HOWEVER...THE GEM AND SREF ARE A BIT COOLER SHOWING SNOW
LEVELS NEAR 6000 FEET. WILL HAVE TO KEEP AN EYE ON THIS FOR
POTENTIAL LATE SEASON WINTER WEATHER IMPACTS ACROSS THE HIGH
ELEVATION MOUNTAIN PASSES. THANKFULLY...ANY SNOW WILL NOT LAST
TOO LONG ACROSS THE LOWER ELEVATIONS. COOLER THAN AVERAGE
TEMPERATURES ARE EXPECTED MONDAY...AND POTENTIALLY TUESDAY...WITH
HIGHS IN THE UPPER 40S TO MID 50S.

MODELS THEN SHOW A HIGH AMPLITUDE RIDGE OF HIGH PRESSURE ALOFT
MOVING EASTWARD INTO WESTERN COLORADO AND WYOMING FOR THE MIDDLE
PART OF NEXT WEEK. THE ECMWF SHOWS A FLATTER RIDGE...WITH THE
RIDGE AXIS QUICKLY SLIDING EASTWARD INTO THE GREAT PLAINS BY
THURSDAY. EITHER WAY...TEMPERATURES WILL INCREASE ABOVE SEASONAL
AVERAGES WITH HIGHS IN THE UPPER 60S TO UPPER 70S ACROSS MOST OF
THE FORECAST AREA BY THURSDAY. THERE IS A LOW CHANCE OF
PRECIPITATION (BELOW 10 PERCENT) THROUGH WEDNESDAY...BUT SHOWER
AND TSTORM COVERAGE WILL LIKELY INCREASE BY THURSDAY AND
ESPECIALLY FRIDAY AS THE RIDGE AXIS PUSHES EASTWARD AND WEAKENS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH TONIGHT)

VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING. WIDELY SCATTERED
SHOWERS AND TSTORMS WILL DEVELOP ACROSS SOUTHEAST WYOMING AND MOVE
SOUTH AND EAST INTO WESTERN NEBRASKA BY LATE THIS AFTERNOON. DUE
TO LIMITED CONFIDENCE WITH TIMING...WILL JUST ADD VCTS FOR MOST
TERMINALS IN THE AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 406 AM MDT FRI APR 24 2015

UNSETTLED WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK.
PRECIPITATION WILL BECOME WIDESPREAD THIS WEEKEND AS AN UPPER
LEVEL LOW SLOWLY MOVES ACROSS THE FOUR CORNERS REGION. NO CRITICAL
FIRE WEATHER CONCERNS THROUGH AT LEAST THE MIDDLE OF 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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