Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 060544 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1142 PM MDT SAT JUL 5 2014

.SHORT TERM...TODAY THROUGH SUNDAY (ISSUED AT 232 PM MDT)

A MILD NIGHT IS EXPECTED FOR MUCH OF THE FORECAST AREA AS A VERY
WARM AND DRY AIRMASS REMAINS UNDERNEATH THE RIDGE. A SHORT WAVE
PASSING WELL TO OUR NORTH WILL KICK DOWN A DRY COLD FRONT INTO
NORTHERN WYOMING TONIGHT. THE FRONT WILL NOT HAVE MUCH IMPACT ON
THE SENSIBLE WEATHER...JUST PERHAPS A WIND SHIFT TO THE NORTH AND
A POTENTIAL SHOWER OR THUNDERSTORM IN THE BIGHORNS OR NORTHERN
ABSAROKAS. THE FRONT WILL SETTLE ALONG THE DIVIDE AND BRING SOME
HIGHER RELATIVE HUMIDITIES TO THE AREA FOR SUNDAY...WHICH COULD
HELP SOME CONVECTION IGNITE ON SUNDAY AFTERNOON BUT WE ARE STILL
CAPPED SOMEWHAT BY THE RIDGING ALOFT. ONLY ISOLATED ACTIVITY IS
EXPECTED ACROSS THE NORTH AND NORTHEAST WHERE HEIGHTS ARE ALLOWED
TO LOWER A BIT AS THE RIDGE AXIS SHIFTS WEST. EVEN BEHIND THE
FRONT...IT WILL REMAIN HOT AND DRY BUT A FEW DEGREES COOLER THAN
WHAT WAS EXPERIENCED TODAY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

WEST FLOW ALOFT WILL BE OVER WESTERN AND CENTRAL WYOMING WITH A
FLAT HIGH PRESSURE RIDGE ALOFT OVER THE SOUTHERN GREAT BASIN AND THE
POLAR FRONT AND JET OVER NORTHERN MONTANA AND SOUTHERN CANADA.  WEAK
SURGES OF SUBTROPICAL MOISTURE WILL BE BROUGHT NORTH FROM THE GREAT
BASIN BY THE HIGH TO THE SOUTH IMPACTING MAINLY THE SOUTHWEST WHILE
WEAK SHORT WAVE TROUGHS MOVING EAST ALONG THE POLAR JET WILL BRUSH
NORTHERN WYOMING.  OVERALL THE NORTHERN AND WESTERN MOUNTAINS WILL
HAVE THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS...WHILE MORE
ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL BRUSH
THE FAR SOUTHWEST AREA.  A COLD FRONT WILL BE SENT SOUTH BY THE
POLAR FRONT INTO NORTHERN EASTERN AND CENTRAL AREAS SUNDAY EVENING
PUSHING SOUTH INTO THE SOUTHWEST LATER SUNDAY NIGHT WITH COOLING
ACROSS THE AREA...MOST NOTICEABLE IN THE NORTH AND EAST.  A STRONGER
SURGE OF COOL AIR WILL MOVE SOUTH TUESDAY...WASHING OUT TUESDAY
NIGHT AS WESTERLIES INTENSIFY AND THE SOUTHERN HIGH SENDS WARMER AIR
NORTH. THIS WILL BRING INCREASED TEMPERATURES WEDNESDAY THROUGH
SATURDAY.  OVERALL MODELS ARE IN GOOD AGREEMENT IN THE MID AND
EXTENDED PERIODS WITH THE UPPER AIR PATTERN AND DIFFER MOST IN THE
LOCATION AND INTENSITY OF AFTERNOON AND EARLY EVENING CONVECTION.

&&

.AVIATION.../06Z ISSUANCE/

VFR/NSW CONDITION WITH UNLIMITED CIGS WILL PREVAIL THROUGH 20Z
SUNDAY.  AN UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL
PUSH EAST ACROSS MONTANA ON SUNDAY WITH ISOLD HIGH-BASED TS AND
-SHRA DEVELOPING VCNTY AND NORTH OF KCOD-KCPR LINE FROM 21Z SUN-03Z
MON...WITH THIS ACTIVITY PRIMARILY EAST OF THE BIGHORN RANGE BY 06Z
MON.  A DRIER AIRMASS WILL PREVAIL FURTHER SOUTH SUNDAY AFTN WITH A
PREVAILING NW SFC WIND 10-15KTS.

&&

.FIRE WEATHER...

DRY AND HOT CONDITIONS REMAIN WITH HUMIDITY FALLING BELOW 15
PERCENT IN MANY AREAS. A GUSTY BREEZE WILL BE PRESENT IN SOME
LOCATIONS INTO THE EARLY EVENING HOURS...THIS COMBINATION OF
ELEMENTS LED TO A RED FLAG WARNING THIS AFTERNOON...IT WILL BE
ALLOWED TO EXPIRE AT 9PM DUE TO THE INTRODUCTION OF A DRY COLD
FRONT EAST OF THE DIVIDE TONIGHT...THIS FRONT WILL SWITCH WINDS TO
THE NORTH/NORTHEAST AND INTRODUCE HIGHER RELATIVE HUMIDITIES.
WINDS ALONG AND BEHIND THE FRONT ARE NOT VERY STRONG...IN THE
NEIGHBORHOOD OF 10 TO 15 MPH. ANOTHER WEAK COLD FRONT MOVING
SOUTHWARD SUNDAY NIGHT WILL BRING COOLER TEMPERATURES AND SOMEWHAT
HIGHER HUMIDITY FOR THE BEGINNING OF THE NEXT WORK WEEK. THERE
WILL BE A CHANCE FOR THUNDERSTORMS ALONG AND EAST OF THE DIVIDE
THROUGH THE WEEK WITH A DECENT CHANCE FOR A WETTING RAIN ON
TUESDAY AND FRIDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...ALLEN
LONG TERM...C.BAKER
AVIATION...AEM
FIRE WEATHER...ALLEN






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