Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 071221
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
621 AM MDT MON JUL 7 2014

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 417 AM MDT MON JUL 7 2014

EARLY MORNING CONVECTION ONGOING ACROSS SRN MT/NRN WY IS
ASSOCIATED WITH 85+ KNOT H3 JET STREAK AND ASSOCIATED SHORTWAVE
ENERGY DIVING SOUTHEAST ACROSS MT. LATEST RETURNS FROM KUDX SHOWS
STORMS MOVING SE ACROSS WESTON/CROOK COUNTIES IN NE WY. UNDER ITS
CURRENT TRAJECTORY THE BULK OF THIS ACTIVITY WILL REMAIN NORTH OF
THE CWFA. DID ADD SOME LOW END THUNDERSTORM CHANCES ACROSS FAR NRN
CONVERSE/NIOBRARA/SIOUX AND DAWES COUNTIES THRU 15Z SHOULD ANY
SOUTHWARD DEVELOPMENT OCCUR. OTHERWISE...WILL SEE MAIN SFC COOL
FRONTAL SURGE INTO NRN ZONES BY MID-MORNING AND MOVING SOUTH
ACROSS THE REST OF SE WY AND WRN NEBRASKA BY MID/LATE AFTERNOON.
00Z MODELS HAVE BACKED OFF ON PRECIP POTENTIAL LATER TODAY...MOST
LIKELY DUE TO AT LEAST IN PART DUE TO CONTAMINATION FROM THIS
MORNINGS CONVECTION. AVAILABLE MID-LEVEL MOISTURE HAS ALSO
DECREASED FROM EARLIER MODEL OUTPUT. EVEN SO...MODELS SHOW AROUND
1500 J/KG OF SBCAPE IN THE POST FRONTAL AIR MASS THIS AFTERNOON.
DEEP LAYER SHEAR OF AROUND 30-40 KNOTS THIS MORNING INCREASES TO
AROUND 60 KNOTS BY LATE AFTERNOON. THIS IS ENOUGH TO WARRANT AT
LEAST ISOLATED THUNDERSTORM CHANCES GOING FOR AREAS ALONG AND EAST
OF THE LARAMIE RANGE. TEMPERATURES WILL AGAIN BE RATHER WARM TODAY
WITH 80S EXPECTED MOST LOWER ELEVATIONS...WITH LOW 90S ALONG THE
NORTH PLATTE RIVER VALLEY. ANY CONVECTIVE ACTIVITY SHOULD
DISSIPATE QUICKLY THIS EVENING.

A DRY DAY IS IN STORE FOR TUESDAY AS THE FIRST DAY POST FRONTAL
IS TRADITIONALLY BENIGN. COOL NORTHERLY SFC FLOW ALONG WITH
SUBSIDENCE BENEATH THE SFC HIGH WILL USHER VERY PLEASANT
CONDITIONS. HIGH TEMPERATURES TUESDAY WILL BE 5-10F COOLER
COMPARED TO THOSE TODAY. AFTERNOON HIGHS WILL ONLY REACH THE UPPER
70S/LOW 80S ON TUESDAY.

SOUTHEASTERLY LLVL RETURN FLOW ENSUES AGAIN ON TUESDAY NIGHT AND
WEDNESDAY ALLOWING SFC MOISTURE ADVECTION TO RETURN TO THE AREA.
ANOTHER SHORTWAVE AND SLUG OF MID-LEVEL MOISTURE WILL ROTATE
AROUND THE PERIPHERY OF THE UPPER HIGH WEDNESDAY AFTERNOON. PROGD
SBCAPES OF AROUND 1000 J/KG WILL BE FOUND EAST OF THE LARAMIE
RANGE WHICH WILL SET THE STAGE FOR AT LEAST A SLIGHT CHANCE OF
AFTERNOON AND EVENING THUNDERSTORM ACTIVITY. HIGH TEMPERATURES
WILL WARM QUICKLY ON WEDNESDAY...RETURNING TO THE 80S ABOVE 5 KFT
AND 90S BELOW.

.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 417 AM MDT MON JUL 7 2014

MONSOONAL RIDGE IS LOCATED NEAR THE FOUR CORNERS REGION THROUGH
MUCH OF THE EXTENDED PERIOD. 700-500MB FLOW IS LARGELY WEST OR
NORTHWEST...WHICH IS NORMALLY NOT OVERLY CONDUCIVE FOR
TRANSPORTING ABUNDANT SUBTROPICAL MOISTURE INTO THE REGION. PW
VALUES ARE GENERALLY 0.75-1.00 INCHES FROM THURSDAY THROUGH
SUNDAY...WHICH IS HIGH ENOUGH TO WARRANT A SLIGHT CHANCE OF STORMS
EACH AFTN AND EVENING. AT THIS TIME IT IS DIFFICULT TO PINPOINT
WHICH AFTN WILL BE THE MOST CONVECTIVELY ACTIVE AND WILL BE
LARGELY DEPENDENT ON SHORTWAVES MOVING ACROSS THE NORTHERN
PERIPHERY OF THE MIDLEVEL RIDGE. SVR POTENTIAL LOOKS SLIM AS FLOW
ALOFT IS RATHER WEAK. TEMPERATURES WILL LIKELY BE WARMEST ON THURS
AND FRI...AND THEN COOL SLIGHTLY AS WE HEAD INTO THE WEEKEND AS A
COUPLE WEAK FRONTS BACK INTO THE PLAINS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 609 AM MDT MON JUL 7 2014

AN AREA OF SHOWERS AND TSTMS IS MOVING TO THE NORTHEAST OF CDR BUT
IS NOT EXPECTED TO IMPACT THE TERMINAL THROUGH THE MORNING. A
FRONT WILL PUSH ACROSS THE AREA FROM 18-22Z WITH GUSTY NORTHERLY
WINDS DEVELOPING BEHIND IT. THESE WINDS WILL OCCASIONALLY GUST TO
25-30 KTS OVER THE PLAINS THROUGH THE EARLY EVENING. ISOLATED
TSTMS COULD DEVELOP THIS AFTERNOON ACROSS THE PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 417 AM MDT MON JUL 7 2014

ANOTHER SEASONABLY WARM DAY IS IN STORE FOR THE DISTRICTS TODAY AS
HIGHS ONCE AGAIN CLIMB WELL INTO THE 80S AND LOW 90S. A COLD FRONT
WILL SLICE SOUTH THROUGH THE AREA TODAY...TURNING WINDS NORTHERLY
DURING THE AFTERNOON HOURS. MINIMUM RELATIVE HUMIDITIES WILL DIP
INTO THE SINGLE DIGITS AND TEENS AHEAD OF THE FRONT EARLY THIS
AFTERNOON. A COOLER...DRY AND MORE MOIST DAY AHEAD FOR TUESDAY.
WINDS WILL TURN FROM NORTHERLY TO SOUTHEASTERLY ON TUESDAY. THE NEXT
CHANCE FOR SHOWERS AND THUNDERSTORMS WILL RETURN TO MUCH OF THE AREA
ON WEDNESDAY.

&&

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

$$

SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...FINCH
FIRE WEATHER...HAHN






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