000
FXUS65 KRIW 170533
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1133 PM MDT SUN JUN 16 2013

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 352 PM MDT)

MODEST DIRTY RIDGE STILL TRYING TO MAKE ITS WAY INTO WYOMING ...BUT
TAKING THE TORTOISE APPROACH. HEIGHTS ALSO SLOWLY RISING ...HELPING
IN RAISING TEMPERATURES A BIT...AGAIN MODESTLY...WITH GENERALLY 3 TO
5 DEG WARMING OVER YESTERDAY`S HIGH TEMPS. WIND TOO WILL ALSO BE ON
THE MODEST SIDE OF THINGS...BUILDING ANOTHER GREAT DAY FOR THE MOST
PART.

WEAK FRONT HAS MADE ITS WAY DOWN FROM THE NORTH AND SITS NEARLY
DIAGONALLY ACROSS WYOMING FROM NORTHWEST TO SOUTHEAST. MOISTURE
AVAILABILITY IS AND WILL BE EXTREMELY LIMITED WITH WIDESPREAD 20S TO
MID 30 DEW POINTS. 40 DEW POINTS AND SLIGHTLY BETTER BOUNDARY LAYER
MOISTURE WILL MAKE ITS WAY INTO EASTERN JOHNSON COUNTY...AND PERHAPS
INTO NORTHERN OR NORTHEASTERN NATRONA. OVERALL CONVECTIVE SITUATION
WILL BE SPOTTY AT BEST.

NOT SURE LL CONVERGENCE ALONG/NEAR FRONT WILL BE QUITE STRONG ENOUGH
TO BREAK CAP AND SPARK CI BY ITSELF. SLIGHTLY BETTER FORCING ACROSS
SOUTHERN SWEETWATER COUNTY OF ALL PLACES WITH SLIGHT BETTER MOISTURE
TOO...ALL FROM MORE CONVECTION DOWN IN NWRN CO...AND A LITTLE
SHORTWAVE FORCING THERE TOO. SO PERHAPS SOME HIGH BASED CONVECTION
EARLY THIS AFTERNOON FROM ROCK SPRINGS SOUTHWARD AND TO THE EAST.
OTHERWISE IT LOOKS LIKE ELEVATION IN THE FORM OF OUR PERMANENT
FRONTS...THE MOUNTAINS...WILL THE BEST FRIEND FOR MOST CONVECTION.
PERHAPS THE BEST AREAS WOULD BE CLOSE TO WHERE BOTH FRONT AND
MOUNTAINS COINCIDE VERY LATE AFTERNOON...EARLY EVENING...NAMELY
ABSAROKA RANGE...THEN GREEN...RATTLESNAKE...AND DEER CREEK RANGES.
AGAIN...THESE WILL ALL BE ISOLATED CHANCES AT BEST. EVEN MOST
BASINS/VALLEYS ADJACENT TO THESE AREAS WILL BE HARD PRESSED TO GET
MUCH IF ANYTHING FROM WHAT DOES GO UP. GREATEST...ALBEIT STILL
SMALL...POTENTIAL ATTM SEEMS TO BE NW PARK COUNTY AND JOHNSON
COUNTY...AND JOHNSON ONLY IF CAP CAN BE BEAT. DCAPE ALSO LOOKS
MANAGEABLE TODAY WITH RATHER SHALLOW CONVECTION AND WITH GUSTY
ERRATIC WINDS AND NOTHING SEVERE. PLEASANT EVENING FOR THE MOST PART
WITH CONVECTION MOSTLY OUT OF THE PICTURE BEFORE
SUNDOWN.

MONDAY...BL MOISTURE BEGINS TO INCREASE FROM THE SOUTHEAST AROUND
SFC LOW SKIRTING TO OUR SOUTH...PERHAPS MIXING INTO THE BIG HORN
BASIN IN ADDITION TO NATRONA AND JOHNSON COUNTIES ONCE AGAIN. BEST
SHEAR AND THERMODYNAMIC PROFILES WILL BE PRESENT FROM THE NORTHERN
PORTION OF THE BIG HORN BASIN INCLUDING THE CODY AREA...THEN INTO
NATRONA AND JOHNSON COUNTIES. CAP WILL BE MUCH EASIER TO BREAK
MONDAY...ESPECIALLY OVER THE MOUNTAINS AND EVEN SOME OF THE ADJACENT
LOW LANDS...SO POPS ARE APPROPRIATELY HIGHER COMPARED TO TODAY.
ALTHOUGH...GETTING TO SEVERE CONVECTIVE CONDITIONS WILL BE POOR AS
IT LOOKS RIGHT NOW...WITH STRONGEST STANDARD STORM POTENTIAL IN
NATRONA AND JOHNSON COUNTIES WHERE MIX LAYER CAPE HOLDS UP BEST AND
DEEP SHEAR IS MAXIMIZED. STRONG DOWNDRAFT POTENTIAL WILL EXIST
ACROSS SWEETWATER AND FREMONT COUNTIES WHERE DPDS... WILL BE
LARGEST. HOWEVER...HIGH BASES AND RELATIVELY LOW TOPS WILL ALSO KEEP
A CHECK ON THINGS...PROBABLY MOSTLY DISSIPATING THESE SHALLOW STORMS
AS SOON AS THEY BLOW OUT ANYTHING.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

BASED 36-72 HOUR FORECAST MAINLY OFF THE NAM. UPPER LEVEL RIDGE
HOLDS ON OVER THE ROCKIES MONDAY NIGHT INTO EARLY TUESDAY. MID/UPPER
LEVEL LOW PRESSURE JUST OFF PACIFIC NORTHWEST COAST THEN EJECTS
SHORTWAVES INTO THE ROCKIES...AS THE FLOW BECOMES MORE SOUTHWESTERLY
TUESDAY AFTERNOON. LOOKS LIKE ONE NOTABLE DISTURBANCE TUESDAY
AFTERNOON AND EVENING WITH INSTABILITY IN PLACE EAST OF THE
CONTINENTAL DIVIDE. NORTHEAST SECTIONS OF THE FORECAST AREA COULD
VERY WELL SEE THE MOST CONVECTIVE ACTIVITY WITH THIS SHORTWAVE. IN
FACT...TUESDAY LOOKS TO BE MOST ACTIVE WEATHER DAY OF THE WEEK.

UPPER LEVEL LOW THEN MOVES INLAND...INCREASING SOUTHWESTERLY FLOW
OVER THE ENTIRE FORECAST AREA BY WEDNESDAY AFTERNOON. MODELS
INDICATE GOOD MIXING TO THE SURFACE...ELIMINATING ANY LOW LEVEL
MOISTURE. THEREFORE WEDNESDAY INTO WEDNESDAY NIGHT LOOKS DRY AND
BREEZY ACROSS WEST CENTRAL WYOMING.

FOR THE REST OF THE EXTENDED FORECAST PERIOD...A PATTERN CHANGE WILL
TAKE PLACE OVER THE NORTHERN ROCKIES WITH WEST TO SOUTHWEST FLOW
ALOFT. THE ACTUAL LOW TRACKS OVER NORTHERN MONTANA INTO NEXT
WEEKEND. PRECIPITATION SHOULD REMAIN NORTH AND EAST DURING THIS
TIME. CONFIDENCE LIES IN THE WIND FIELDS WITH THIS MORE ZONAL
PATTERN. AS A RESULT...IT WILL BE BREEZY TO WINDY MOUNTAINS AND
LOWER ELEVATIONS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS.

TEMPERATURES SHOULD BE NEAR NORMAL FOR MOST OF THE EXTENDED PERIOD.

&&

.AVIATION.../06Z ISSUANCE/

ISOLATED SHOWERS AND STORMS WILL CONTINUE THROUGH 11Z EAST OF A KCOD-
KRIW LINE. WIND GUSTS TO 35 KNOTS AND BRIEF RAIN CAN BE EXPECTED.
OTHERWISE VFR CONDITIONS THROUGH 12Z.

VFR CONDITIONS WILL OCCUR 12Z MON THROUGH 06Z TUE. SHOWERS AND A FEW
THUNDERSTORMS WILL DEVELOP FROM YELLOWSTONE NATIONAL PARK SOUTHEAST
THROUGH THE WIND RIVER RANGE BY 20Z. THE ACTIVITY WILL MOVE EAST
DURING THE AFTERNOON WITH REDEVELOPMENT OF SHOWERS AND STORMS
THROUGH 05Z TUE. THE MAIN THREATS WILL BE WIND GUSTS TO 40 KNOTS AND
LIGHTNING...WITH RAINFALL BEING BRIEF. MUCH OF THE AREA IN FAR WEST
AND SOUTHWEST WY WILL BE DRY THROUGH 06Z TUE.

&&

.FIRE WEATHER...
PERSISTENT UPPER LEVEL RIDGE WILL CONTINUE NEAR OUR FORECAST AREA FOR
THE NEXT 3-4 DAYS OR SO. A FEW UPPER LEVEL DISTURBANCES WILL RIDE
OVER/ALONG THE RIDGE AT TIMES PROVIDING CHANCES FOR CONVECTION EVERY
DAY THROUGH TUESDAY NEXT. HOWEVER...THE FORECAST REGION WILL BE
SOMEWHAT DIVIDED DIAGONALLY FROM NORTHWEST TO SOUTHEAST WITH
AVAILABLE MOISTURE...SO EXPECT SHOWERS AND THUNDER TO OCCUR ROUGHLY
NORTH OF A JACKSON TO CASPER LINE......ESPECIALLY OVER AND NEAR THE
MOUNTAIN RANGES AND ADJACENT LOWER ELEVATIONS. OTHERWISE...WARM AND
DRY CONDITIONS WILL PERSIST ACROSS THE ENTIRE REGION...BUT
ESPECIALLY SOUTH OF THE ABOVE MENTIONED LINE. BY MID WEEK...DRY
SOUTHWEST FLOW WILL LARGELY OVERTAKE THE REGION IN ADDITION TO
STRONG SURFACE HIGH PRESSURE BUILDING IN...HELPING TO KEEP ANY
RETURN OF MOISTURE TO THE REGION. FIRE POTENTIAL WILL LIKELY BE
ENHANCED DURING THIS PERIOD.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...KPL
AVIATION...AR
FIRE WEATHER...BRAUN