Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 082145
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
345 PM MDT TUE JUL 8 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 140 PM MDT TUE JUL 8 2014

THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS WHEN THE
THUNDERSTORMS WILL MOVE BACK INTO THE PICTURE THIS WEEK.

LATEST RADAR LOOP WAS SHOWING SOME SMALL SHOWERS DEVELOPING OVER
THE SNOWY RANGE. NOT EXPECTING MUCH IN THE WAY OF CONVECTION THIS
AFTERNOON.

TUESDAY NIGHT-WEDNESDAY:
LATEST WATER VAPOR LOOP WAS SHOWING THE DRY SLOT CONTINUING TO
IMPACT THE AREA. HOWEVER...THE STREAM OF MONSOON MOISTURE
STRETCHING FROM THE DESERT SOUTHWEST TO THE PACIFIC NORTHWEST WAS
STARTING TO CREEP EAST TOWARDS IDAHO AND WYOMING THIS AFTERNOON.
THIS IS IN RESPONSE TO THE UPPER LEVEL WAVE MOVING THROUGH BRITISH
COLUMBIA. AS THIS WAVE CONTINUES TO PUSH EAST WE WILL SEE THIS
PLUME OF MOISTURE STARTING PUSHING INTO OUR FORECAST AREA
BEGINNING TOMORROW AFTERNOON AND CONTINUING SPREADING EAST THROUGH
THURSDAY. AS A RESULT...WE WILL SEE THE CHANCES OF SHOWERS AND
THUNDERSTORMS INCREASING ACROSS THE SNOWY AND SIERRA MADRE RANGES
WEDNESDAY AFTERNOON. THE LOW LEVEL AIR MASS MAY DRY OUT BRIEFLY
OVER THE WESTERN HALF OF THE FORECAST TOMORROW MORNING INTO THE
AFTERNOON AS THE SURFACE FLOW TURNS TO THE SOUTHWEST AHEAD OF THE
FEATURE MOVING THROUGH EASTERN WYOMING. MAY SEE A FEW AFTERNOON
THUNDERSTORMS DEVELOP ACROSS SNOWY...SIERRA MADRES AND CHEYENNE
RIDGE TOMORROW AFTERNOON AS A WEAK SURFACE BOUNDARY MOVES THROUGH
THE AREA IN COMBINATION WITH THE 700-500MB MOISTURE INCREASING.
SHEAR VALUES WILL BE QUITE MARGINAL 30-35KTS...BUT THE MOISTURE
WILL BE QUITE RICH IN THE PANHANDLE WHICH MAY FAVOR A COUPLE OF STRONG
TO SEVERE STORMS AFTER THE BOUNDARY PASSES THROUGH.

WEDNESDAY NIGHT-THURSDAY NIGHT:
THE STRONGER SHORTWAVE IS PROGGED TO CONTINUE PUSHING EAST ACROSS
THE NORTHERN ROCKIES INTO THE NORTHERN PLAINS ON WEDNESDAY NIGHT
INTO THURSDAY. THIS WILL SEND ANOTHER FRONTAL BOUNDARY THROUGH AREAS
MAINLY EAST OF THE LARAMIE RANGE ON THURSDAY. AHEAD OF THIS
BOUNDARY...WE MAY SEE SOME CONVECTION LINGER ACROSS THE LARAMIE
RANGE AND HIGH PLAINS WEDNESDAY NIGHT DUE TO MARGINAL UPSLOPE FLOW
AHEAD OF THE WAVE. IN ADDITION...WE MAY SEE A CLUSTER OF
THUNDERSTORMS MOVING THROUGH NORTHERN WYOMING LATE WEDNESDAY
NIGHT. MOST OF THE CONVECTION WILL BE ELEVATED BEHIND THE
BOUNDARY...BUT WITH LIMITED SHEAR I WOULD NOT EXPECT MUCH IN THE
WAY OF SEVERE WEATHER. MEANWHILE...MORE SHOWERS AND THUNDERSTORMS
MAY DEVELOP BEHIND THE BOUNDARY IN THE NEBRASKA PANHANDLE ON
THURSDAY AFTERNOON...BUT DUE TO LIMITED SHEAR LESS THAN 30KTS AND
INSTABILITY GENERALLY RANGING FROM 1000-1500 J/KG...WOULD NOT EXPECT
MUCH IN THE WAY OF SEVERE WEATHER.


.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 428 AM MDT TUE JUL 8 2014
BY LATE IN THE WEEK...THE MODELS REMAIN IN GOOD AGREEMENT DEPICTING
A FAIRLY DEEP TAP OF 700-500 MB MOISTURE WILL COME UP FROM THE
EASTERN PACIFIC...SPREADING NORTHWARD IN A MONSOONAL SOUTHWESTERLY
UPPER FLOW PATTERN ACROSS OUR FORECAST AREA.  WE MAINTAINED THE
PREVIOUS TREND OF KEEPING CHANCE POPS GOING MOST AREAS FRIDAY
THROUGH EARLY NEXT WEEK. FRIDAY STILL LOOKS TO BE OUR MOST ACTIVE
DAY WITH ALL OF THE INGREDIENTS COMING TOGETHER FOR AN INCREASED
CHANCE FOR ORGANIZED SEVERE STORMS.  MOST NOTABLY...THE GFS IS
ADVERTISING MUCAPES 1200-2500 J/KG OVER THE SOUTHEASTERN HALF OF OUR
FORECAST AREA FRIDAY AFTERNOON AND EVENING...AND THOSE PROJECTED
VALUES MAY BE A BIT UNDERDONE GIVEN THE MODEL BIAS. THE DEEPEST
INSTABILITY COINCIDES WITH SUFFICIENT BULK SHEAR VALUES OF 30 TO 40
KTS...MEANING POTENTIAL FOR STRONGER/LONGER LIVED ROTATING
UPDRAFTS.  WE KEPT AFTERNOON/EVENING CHANCES FOR THUNDERSTORMS GOING
ON INTO TUESDAY GIVEN LINGERING DEEP-LAYERED MOISTURE AND AN ACTIVE
NORTHWESTERLY UPPER FLOW PATTERN AS THE UPPER RIDGE MIGRATES BACK
WEST...BUT APPEARS TO BE FAR ENOUGH SOUTH TO WHERE WE WOULD SEE
PASSING SHORTWAVE ENERGY COMING OVER THE TOP OF THE RIDGE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1140 AM MDT TUE JUL 8 2014

THE MAIN CONCERN WITH THIS TAF ISSUANCE IS WHEN THE CLOUDS WILL
BEGIN TO LIFT NORTHEAST OUT OF THE FORECAST AREA.

LATEST VISIBLE IMAGERY/OBSERVATIONS WERE SHOWING THE MVFR CEILINGS
BEGINNING TO CLEAR OUT WITH THE CURRENT DECK BEING AROUND 4-6KFT.
THIS CLOUD DECK SHOULD CONTINUE TO LIFT NORTHEAST DURING THE NEXT
SEVERAL HOURS AND SHOULD EXIT THE CYS TAF SITE AROUND 20Z WHILE
THE PANHANDLE TAF SITES SHOULD SEE THINGS CLOUD UP DURING THE
REMAINDER OF THE AFTERNOON. NOT EXPECTING ANY SHOWER ACTIVITY WITH
THESE CLOUDS SINCE THINGS ARE QUITE CAPPED ALOFT. HOWEVER...WE
COULD SEE SOME CONVECTION DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON...BUT WITH LIMITED CAPE AND SHEAR...WE WOULD NOT EXPECT
MUCH IN THE WAY STRONG TO SEVERE ACTIVITY. WIND SPEEDS SHOULD
REMAIN FAIRLY LIGHT. LARAMIE IS A BIT GUSTY...BUT SHOULD BEGIN TO
DIMINISH DURING THE AFTERNOON.


&&

.FIRE WEATHER...
THE AIR MASS MAY DRY OUT A BIT ACROSS AREAS WEST OF THE LARAMIE
RANGE WEDNESDAY AFTERNOON AS THE SURFACE FLOW TURNS TO THE
SOUTHWEST AHEAD OF A COUPLE OF UPPER LEVEL DISTURBANCES. OTHERWISE...
SHOWER AND THUNDERSTORM CHANCES WILL BE ON THE INCREASE DURING
THE NEXT SEVERAL DAYS AS THE MONSOON FLOW BEGINS TO MOVE INTO THE
PICTURE AND INCREASES THE CHANCES OF SHOWERS AND THUNDERSTORMS
BEGINNING LATE WEDNESDAY AND CONTINUING INTO THE WEEKEND.


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

$$

SHORT TERM...REC
LONG TERM...JG
AVIATION...REC
FIRE WEATHER...REC





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