Area Forecast Discussion
Issued by NWS Riverton, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
000
FXUS65 KRIW 050527
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1127 PM MDT TUE AUG 4 2015

.SHORT TERM...TONIGHT THROUGH WEDNESDAY (ISSUED AT 205 PM MDT)

LINGERING CLOUDS WITH SCATTERED SHOWERS CONTINUE ACROSS NORTHERN
AND EASTERN PORTIONS OF THE FORECAST AREA. ISOLATED THUNDERSTORMS
ARE ALSO DEVELOPING ALONG THE EASTERN SIDE OF THE BIGHORNS. EXPECT
THIS ACTIVITY TO CONTINUE THROUGH THE REST OF THE
AFTERNOON...BEFORE THIS SYSTEM EXITS THE AREA THIS EVENING.
LOCALLY HEAVY RAIN ALSO REMAINS POSSIBLE WITH ANY STRONG STORM
THAT DEVELOPS.

DRIER AIR OVER SOUTHWESTERN PORTIONS WILL SPREAD EASTWARD BEHIND
THIS SYSTEM...CLEARING THE CLOUDS ACROSS THE AREA TONIGHT. THIS
WILL BE SHORT-LIVED HOWEVER...AS ANOTHER SHORTWAVE WILL IMPACT
WESTERN PORTIONS BY SUNRISE. CLOUDS WILL INCREASE IN THIS AREA BY
12Z WEDNESDAY...ALONG WITH ISOLATED TO SCATTERED SHOWERS. THIS
ACTIVITY WILL INCREASE THROUGHOUT THE MORNING HOURS...BECOMING
OVERCAST WITH SHOWERS GIVING WAY TO THUNDERSTORMS. STORM CHANCES
WILL ALSO SPREAD EAST OF THE DIVIDE BY EARLY AFTERNOON. GUSTY
WINDS AND LOCALLY HEAVY RAIN WILL BE THE MAIN THREATS WITH THESE
STORMS. GUSTY SOUTHWEST WINDS WILL ALSO OCCUR AHEAD OF THIS
SYSTEM...FROM SOUTHERN LINCOLN TO SOUTHWESTERN NATRONA COUNTY.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY NIGHT

WEDNESDAY NIGHT WILL SEE THE FAST MOVING SHORTWAVE TROUGH EXIT
WYOMING TO THE EAST...WITH SHOWERS AND THUNDERSTORMS IN THE
EVENING...AND RESIDUAL SHOWERS IN THE BIGHORNS AND JOHNSON COUNTY
AFTER MIDNIGHT.  LIKELY TO SEE BREEZY CONDITIONS KEEP UP OVERNIGHT
AND INTO THURSDAY MORNING WITH THE TIGHTER GRADIENT IN THE MID
LEVELS.  THURSDAY WILL RESULT IN A BREEZY SEASONAL DAY AS
WELL...REMINISCENT OF MID SEPTEMBER.  THE UPPER LEVEL HIGH LOOKS TO
STRENGTHEN ON FRIDAY OVER THE TEXAS PANHANDLE...BRINGING MOISTURE
AND WEAK INSTABILITY UP FROM THE SOUTHWEST US AND GREAT BASIN.  WEAK
CHANCE OF SHOWERS AND THUNDERSTORMS IN SOUTHWEST WY FRIDAY AFTERNOON
AND EVENING.  WHILE 700MB TEMPS INCREASE A COUPLE OVER
THURSDAY...CLOUD COVER LIKELY TO EFFECT AFTERNOON HIGH
TEMPERATURES...ESPECIALLY SW AND CENTRAL WY.  ON SATURDAY...ANOTHER
SHORTWAVE TROUGH SIMILAR TO WEDNESDAY SYSTEM WILL APPROACH AND
AFFECT NORTHWEST WY.  EXPECTING A DRY SLOT THOUGH TO IMPACT SW TO
CENTRAL WY WITH BREEZY RELATIVELY DRY CONDITIONS...WHILE NW AND
NORTHERN WY TO SEE SCATTERED SHOWERS AND THUNDERSTORMS.  LINGERING
SHOWERS TO HAND AROUND NORTHERN WYOMING OVERNIGHT.  THE FIRST PART
OF THE LONG TERM IS FAIRLY CONSISTENT WITH THE GUIDANCE.

SUNDAY THEN LOOKS TO BE A TYPICAL AUGUST DAY AS THE UPPER LEVEL
RIDGE BUILDS BACK OVER THE ROCKIES.  MONDAY AND TUESDAY ARE EXPECTED
TO SEE TEMPERATURES INCREASE TO UPPER 80S TO LOW 90S...NOT HOT BUT
WARMER THAN WHAT HAS BEEN.  BOTH THE GFS AND ECMWF SWING MORE
MONSOON LIKE CONDITIONS INTO WY ON TUESDAY...SO HAVE BROUGHT BACK A
CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY.  MUCH OF THIS
FORECAST WILL DEPEND ON THE LOCATION AND STRENGTH OF A PAC NW
TROUGH.  THE GFS IS TRENDING A STRONGER MORE NORTHERLY
SOLUTION...WHICH THE 12Z ECMWF HAS COME MORE IN LINE WITH.
OVERALL...THE HEAT APPEARS TO BE STAYING TO THE SOUTH OF WY FOR THE
NEXT 10 DAYS.

&&

.AVIATION.../06Z ISSUANCE/

ISOLATED SHOWERS AND STORMS WILL OCCUR OVER NW WY THROUGH 12Z. A
WEATHER SYSTEM WILL MOVE TOWARD WY WEDNESDAY AFTERNOON AND ACROSS
NORTHERN WY WEDNESDAY NIGHT. SHOWERS AND STORMS WILL FORM OVER
WESTERN WY AROUND 18Z AND THIS ACTIVITY WILL MOVE EAST DURING THE
AFTERNOON AND EVENING HOURS. EXPECT LOCAL MVFR CONDITIONS IN HEAVY
RAIN. MOUNTAINS WILL BE OBSCURED AT TIMES. A COLD FRONT WILL PUSH
THROUGH WY FROM 00Z TO 06Z THURS WITH A WIND SHIFT TO THE NORTH OR
NORTHWEST.

&&

.FIRE WEATHER...

FIRE DANGER REMAINS RELATIVELY LOW THIS AFTERNOON...AS INCREASED
MOISTURE ACCOMPANYING AN UPPER LEVEL DISTURBANCE CONTINUES ACROSS
THE FORECAST AREA. THIS FEATURE WILL FINALLY EXIT THE AREA LATER
TONIGHT. SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR FROM THE
BIG HORN BASIN...EASTWARD TO JOHNSON AND NATRONA COUNTIES. THE
STRONGER STORMS IN THESE AREAS MAY PRODUCE HEAVY RAINFALL. NORTHWEST
PORTIONS MAY SEE SOME ISOLATED ACTIVITY LATER THIS EVENING INTO
THE OVERNIGHT HOURS. SHOWERS AND THUNDERSTORMS WILL INCREASE
THROUGH THE MORNING HOURS WEDNESDAY IN THIS AREA...BEFORE
SPREADING EAST OF THE DIVIDE BY EARLY TO MID AFTERNOON. GUSTY
WINDS AND LIGHTNING WILL BE THE MAIN THREATS FROM THIS ACTIVITY. WINDS
WILL ALSO INCREASE OUT OF THE SOUTHWEST ACROSS THE SOUTHERN AND
SOUTHWESTERN ZONES. DRY WEATHER RETURNS THURSDAY...WITH GUSTY WEST
WIND ACROSS THE SOUTHERN ZONES ALLOWING FOR ENHANCED FIRE DANGER.

&&

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

&&

$$

SHORT TERM...LAVOIE
LONG TERM...MCDONALD
AVIATION...AR
FIRE WEATHER...LAVOIE



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.