Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 140928
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
328 AM MDT MON JUL 14 2014

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 325 AM MDT MON JUL 14 2014

ISOLATED RAIN SHOWERS AND A FEW LIGHTNING STRIKES HAVE BEEN
OBSERVED EARLY THIS MORNING OVER THE SOUTHERN NEBRASKA PANHANDLE
ALONG WITH PORTIONS OF CENTRAL WYOMING. THIS ACTIVITY IS LIKELY IN
RESPONSE TO A RELATIVELY STRONG COLD FRONT SLOWLY MOVING SOUTHWEST
ACROSS THE HIGH PLAINS AND A STRONG JET STREAM DEVELOPING ALOFT.
MOISTURE PROFILES HAVE NOT BEEN A PROBLEM IN THIS PATTERN RECENTLY
WITH DEEP MOISTURE OVER MOST OF THE FORECAST AREA. STRONG COLD
FRONT FOR THIS TIME OF THE YEAR IS DUE TO A STRONG UPPER LEVEL
TROUGH DIGGING SOUTH ACROSS THE GREAT LAKES REGION EARLY THIS
WEEK. BEHIND THIS FRONT...AN ATYPICAL 1025MB SURFACE HIGH WILL
ESTABLISH ITSELF ACROSS THE NORTHERN AND CENTRAL PLAINS THROUGH
THE SHORT TERM FORECAST PERIOD. A THERMAL LOW WILL REMAIN WEST OF
THE CONTINENTAL DIVIDE...RESULTING IN GOOD UPSLOPE EAST TO
NORTHEAST FLOW IN ADDITION TO GOOD CONVERGENCE ALONG THE COLD
FRONTAL BOUNDARY. THIS FRONT WILL PUSH ACROSS THE HIGH PLAINS BY
EARLY THIS AFTERNOON AND STALL SOMEWHERE NEAR THE LARAMIE RANGE BY
TONIGHT. KEPT A RISK OF WIDELY SCATTERED TSTORMS IN THE FORECAST
ALONG AND WEST OF I25 TODAY DUE TO THE POSITION OF THE FRONT
ACTING AS A CONVERGENCE BOUNDARY AND DEEP ENOUGH LLVL MOISTURE AND
SOME LLVL INSTABILITY. COVERAGE IS NOT EXPECTED TO BE TOO GREAT
TODAY DUE TO QUITE A BIT OF DRY AIR ALOFT BETWEEN 15K TO 20K FEET
MSL. HOWEVER...THIS WILL QUICKLY CHANGE ON TUESDAY. TEMPERATURES
WILL CONTINUE TO BE BELOW NORMAL TODAY WITH HIGHS IN THE MID 70S
TO LOW 80S. THE WARMEST TEMPERATURES ARE ACTUALLY EXPECTED TO BE
ACROSS THE LOWER ELEVATIONS OF CARBON COUNTY THIS AFTERNOON...WITH
HIGHS NEAR 90 SOUTH OF RAWLINS.

ON TUESDAY...MODELS CONTINUE TO INDICATE A POTENT UPPER LEVEL
SHORTWAVE DISTURBANCE DIGGING SOUTHWARD ACROSS MONTANA AND
WYOMING. WITH DEEP MOISTURE ALREADY PRESENT ACROSS THE
AREA...COMBINED WITH DYNAMIC FORCING ASSOCIATED WITH THE
SHORTWAVE...THERE IS CONCERN OF SEVERE WEATHER ALONG WITH FLOODING
BY LATE TUESDAY AND INTO WEDNESDAY. MODELS CONTINUE TO SHOW
CONVECTION RAPIDLY DEVELOPING TUESDAY AFTERNOON ACROSS SOUTHEAST
WYOMING AS THE SHORTWAVE DIGS SOUTH ALONG WITH A STRONG JET FOR
THIS TIME OF THE YEAR. THIS FEATURE WILL ALSO TAKE ITS TIME
MOVING ACROSS THE AREA...SO EXPECTED SHOWERS AND TSTORMS TO
CONTINUE THROUGH THE NIGHT AND INTO WEDNESDAY MORNING. ALL MODELS
SHOW RESPECTABLE QPF VALUES...ESPECIALLY ACROSS THE HIGH PLAINS
WHERE MANY LOCATIONS DO NOT NEED THE HEAVY RAINFALL RATES DUE TO
AN ALREADY SATURATED GROUND. IN ADDITION...THE GFS...ECMWF AND
NAM ALL SHOW SIGNIFICANT 0-6KM SHEAR AND EVEN 25 TO 35 KNOTS OF
0-2KM SHEAR ACROSS SOUTHEAST WYOMING AND FAR WESTERN NEBRASKA.
CONCERN OF SEVERE TSTORMS IS GROWING FOR TUESDAY...WITH LARGE HAIL
AND DAMAGING WINDS THE PRIMARY CONCERN. TEMPERATURES WILL BE
SIMILAR TO MONDAY...BUT LIKELY A FEW DEGREES COOLER.

FOR WEDNESDAY...THE MAIN SHORTWAVE WILL BE SLOW TO MOVE SOUTH OF
THE AREA AS ALL MODELS SHOW THE FEATURE REMAINING OVER CENTRAL TO
SOUTHERN WYOMING. SHOWERS AND TSTORMS WILL CONTINUE THROUGH THE
DAY...BUT TSTORMS ARE NOT EXPECTED TO BE SEVERE DUE TO COOLER AIR
MOVING INTO THE AREA. HIGHS ON WEDNESDAY WILL STRUGGLE TO REACH 70
DEGREES ACROSS MOST LOCATIONS.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 300 AM MDT MON JUL 14 2014

MODELS HAVE BEEN CONSISTENT WITH PLACEMENT AND TIMING OF SHORTWAVE
ENERGY WEDNESDAY. ITS LIKELY THERE WILL A LOT OF CLOUD COVER AND
COOL AIR AROUND FOLLOWING TUESDAY NIGHT SHOWER AND THUNDERSTORM
ACTIVITY. CLOUDS AND COOL BOUNDARY LAYER WILL REDUCE THE POTENTIAL
FOR STRONG THUNDERSTORMS WEDNESDAY BUT WILL NOT STRONGER STORMS NOT
COMPLETELY OUT OF THE QUESTION. ALSO SHEAR VALUES WILL BE MUCH LESS
THAN THE PREVIOUS DAY AS THE CORE OF THE UPPER LEVEL JET SHIFTS
SOUTH OF THE AREA. AT ANY RATE THERE WILL ENOUGH UPPER LEVEL FORCING
AND INSTABILITY FOR ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
WEDNESDAY AFTERNOON AND EVENING.

DRY THURSDAY AS HEIGHTS RISE ACROSS THE CENTRAL ROCKIES. COULD SEE AN
ISOLATED SHOWER IN THE HIGHER ELEVATIONS OF SOUTHEAST WYOMING BUT
THAT WOULD BE ABOUT IT FOR PRECIPITATION CHANCES THURSDAY. FRIDAY
FAIRLY SIMILAR TO THURSDAY BUT UPPER LEVEL JET INCREASING SLIGHTLY
IN STRENGTH AND MODELS HINTING AS WEAK IMPULSES MOVING THROUGH THE
UPPER LEVEL FLOW. MAIN CHANCE FOR CONVECTION WILL AGAIN BE IN THE
MOUNTAINS BUT NOT OUT OF THE REALM OF POSSIBILITY FOR A SHOWER OR
THUNDERSTORM TO WORK ITS WAY INTO THE PLAINS.

STRONGER SHORTWAVE WILL SKIRT JUST NORTH OF THE AREA SATURDAY MOVING
ACROSS NORTHEAST WYOMING. AGAIN A FEW SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE BUT THE MAIN AREA OF PRECIPITATION SHOULD BE NORTH OF
THE FORECAST AREA AND INTO WESTERN SOUTH DAKOTA SATURDAY
AFTERNOON/EVENING. ZONAL FLOW SUNDAY WITH RISING HEIGHTS AND WARMER
TEMPERATURES. AFTER A FEW DAYS WITH BELOW NORMAL TEMPERATURES
WEDNESDAY AND THURSDAYS SHOULD BE BACK TO NEAR NORMAL TO SLIGHTLY
ABOVE NORMAL BY SUNDAY.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1132 PM MDT SUN JUL 13 2014

LIGHT WINDS AND SCT MID/HIGH CLOUDS WILL PREVAIL OVERNIGHT ACROSS
THE FORECAST AREA. A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
AND WEST OF THE LARAMIE RANGE MONDAY AFTERNOON WITH GUSTY WINDS AND
LIGHT RAIN ANTICIPATED FROM THIS ACTIVITY.  NORTHEAST WINDS WILL
INCREASE BETWEEN 16 AND 19Z ACROSS THE EASTERN PLAINS...WITH GUSTS
TO 20 KTS LOOKING TO OCCUR THROUGH THE AFTERNOON. WINDS WILL EASE
AND THUNDERSTORMS WILL DIMINISH THROUGH THE EVENING.


&&

.FIRE WEATHER...
ISSUED AT 240 AM MDT MON JUL 14 2014

MINIMAL FIRE WEATHER CONCERNS THIS WEEK AS A COLD FRONT WILL MOVE
ACROSS THE AREA IN ASSOCIATION WITH A POTENT UPPER LEVEL
DISTURBANCE. COOLER THAN NORMAL TEMPERATURES ARE EXPECTED WITH A
GOOD CHANCE OF WIDESPREAD WETTING RAINFALL TUESDAY AND WEDNESDAY.
DRIER CONDITIONS ARE EXPECTED BY LATE THIS WEEK WITH WARMER
TEMPERATURES.

&&

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

$$

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







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