Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 020839
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
239 AM MDT THU JUL 2 2015

.SHORT TERM...THURSDAY THROUGH SATURDAY NIGHT

THERE IS STILL A BIT OF CONVECTION OUT THERE AT THIS EARLY MORNING
HOURS BUT IT APPEARS TO BE WEAKENING AND SHOULD SHIFT OUT OF THE
AREA BY ISSUANCE TIME. AFTER THAT IS LOOKS MAINLY DRY THROUGH THE
MORNING HOURS. AS FOR THURSDAY...THE COVERAGE OF THUNDERSTORMS WILL
CONTINUE TO DECREASE AS HEIGHTS RISE A LITTLE AND PRECIPITABLE WATER
VALUES CONTINUE TO FALL. ALSO..WITH SLIGHT COOLER TEMPERATURES
INSTABILITY SHOULD BE A BIT LESS. HOWEVER...THERE WILL STILL BE A
BIT OF LEFTOVER JET ENERGY IN THE FORM OF THE RIGHT REAR QUAD OF A
JET STREAK MOVING AWAY FROM THE AREA. ALSO...A DYING FRONTAL
BOUNDARY WILL STILL BE IN THE AREA. AS A RESULT..WE DID EXPAND
COVERAGE OF THUNDERSTORMS A BIT EAST OF THE DIVIDE.
HOWEVER...STEERING FLOW LOOKS TO BE VERY WEAK SO THE VAST MAJORITY
OF STORMS WILL LIKELY STAY OVER THE MOUNTAINS. BUT EVEN
HERE...MOST OF THE DAY WILL LIKELY STAY RAIN FREE. THE
THUNDERSTORMS SHOULD CONTINUE TO WANE INTO THE EVENING AND END
AFTER MIDNIGHT...MUCH LIKE THE PREVIOUS COUPLE OF NIGHTS. AREAS
WEST OF THE DIVIDE LOOK TO REMAIN MAINLY DRY.

COVERAGE OF STORMS SHOULD SHRINK A BIT MORE FOR FRIDAY AS THE RIDGE
EXPANDS A BIT AND CAPS THE ATMOSPHERE A BIT MORE AS WELL. IN
ADDITION...THE ATMOSPHERE WILL CONTINUE TO DRY OUT WITH LESS UPPER
LEVEL SUPPORT. FOR NOW...IT LOOKS LIKE ANY CONVECTION WOULD BE
LIMITED TO THE MOUNTAINS EAST OF THE DIVIDE BUT GIVEN THE GREATER
COVERAGE THAN EXPECTED TO PAST FEW DAYS THIS HAS TO BE WATCHED.

AS FOR INDEPENDENCE DAY...IT LOOKS TO BE HOT AS A FIRECRACKER ACROSS
THE AREA WITH HIGHS IN THE 90S FOR MOST OF THE LOWER ELEVATION.
HOWEVER...THE BIG QUESTION MOST WILL HAVE IS WILL MOTHER NATURE
LIGHT THE FUSE FOR SOME NATURAL FIREWORKS THAT WOULD SPOIL THE
FESTIVITIES OF THE DAY. FOR NOW...FOR MOST AREAS IT LOOKS MAINLY DRY
AS BOTH THE NAM AND GFS RESTRICT THE CONVECTION TO THE HIGHER
ELEVATIONS. THE BEST CHANCE OF THUNDERSTORMS MAY ACTUALLY SHIFT WEST
OF THE DIVIDE AS A SURGE OF MOISTURE MOVES IN FROM THE WEST. A
CHANGE IN THE PATTERN MAY ARRIVE FOR SUNDAY...BUT MY COLLEAGUE ON THE
LONG TERM SIDE WILL HAVE THE ANXIOUSLY AWAITED NEWS BELOW.


.LONG TERM...SUNDAY THROUGH THURSDAY

AFTER A HOT FOURTH OF JULY...A COLD FRONT...ASSOCIATED WITH A
TROUGH PUSHING ACROSS THE CANADIAN PRAIRIE PROVINCES...WILL SWEEP
ACROSS THE AREA SUNDAY. HIGH TEMPERATURES ARE EXPECTED TO BE 10
TO AS MUCH AS 20 DEGREES COOLER SUNDAY AND MONDAY...WITH THE BIGGEST
COOL DOWN OCCURRING EAST OF THE DIVIDE. THERE WILL BE A DECENT
SHOT AT CONVECTION SUNDAY AND MONDAY ACROSS THE FORECAST AREA...FROM
A COMBINATION OF THE AFOREMENTIONED COLD FRONT...A WEAK UPPER
LEVEL IMPULSE ROTATING EASTWARD OVER THE AREA...AND SOME RIGHT
ENTRANCE UPPER LEVEL JET DYNAMICS. RIGHT NOW...THE BEST SHOT OF
CONVECTION APPEARS TO BE SUNDAY AFTERNOON AND EVENING...BUT WILL
END UP ON HOW EVERYTING COMES TOGETHER ON NOT ONLY TIMING...BUT
COVERAGE OF PRECIPITATION.

THE FRONTAL BOUNDARY IS EXPECTED TO WASH OUT OR LIFT NORTHWARD AS
A WARM FRONT TUESDAY...RESULTING IN A WARMING TREND. GOOD
AVAILABLE MOISTURE...INSTABILITY WILL RESULT IN ISOLATED TO
LOCALLY SCATTERED AFTERNOON AND EVENING THUNDERSTORMS.

GLOBAL MODELS ARE HINTING AT A SHORTWAVE TROUGH PUSHING ALONG THE
CANADIAN/U.S. BORDER WEDNESDAY AND THURSDAY POSSIBLY SENDING
ANOTHER COLD FRONT INTO THE AREA. THIS WOULD INCREASE CHANCES OF
CONVECTION...ESPECIALLY OVER THE NORTHERN PORTIONS OF THE FORECAST
AREA.

&&

.AVIATION.../12Z ISSUANCE/

VFR CONDITIONS WITH FEW-SCT FL150-200 WILL PREVAIL ACROSS THE AREA
THROUGH 18Z THURSDAY. SFC HIGH PRESSURE TO THE NORTH WILL RESULT IN
AN UPSLOPE NE-E SFC FLOW EAST OF THE DIVIDE THURSDAY AFTERNOON.  THE
BEST MOISTURE AND INSTABILITY WILL BE ALONG A STATIONARY FRONTAL
BOUNDARY ALONG THE EAST SLOPES OF THE DIVIDE WITH WIDELY SCT
THUNDERSTORMS EXPECTED PRIMARILY ALONG A VCNTY KCOD-KLND LINE 21Z
THURSDAY-04Z FRIDAY. THUNDERSTORM ACTIVITY WILL BE MORE ISOLATED
FURTHER EAST BEHIND THE FRONTAL BOUNDARY. A DRY AND MORE STABLE
AIRMASS WILL RESULT IN LITTLE OR NO THUNDERSTORM ACTIVITY WEST OF
THE DIVIDE ON THURSDAY.&&

.FIRE WEATHER...

TEMPERATURES WILL BE A FEW DEGREES COOLER AND RELATIVE HUMIDITY WILL
REMAIN ABOVE CRITICAL LEVELS. HOWEVER...FIRE DANGER MAY BE ELEVATED
AT TIMES WITH ANOTHER CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
THAT MAY BRING GUSTY AND ERRATIC WINDS AND LIGHTNING
STRIKES...MAINLY OVER THE HIGHER ELEVATIONS. EXPECT A WARMING TREND
AND A DECREASE IN THUNDERSTORM COVERAGE FOR FRIDAY AND INTO THE
FOURTH OF JULY.

&&

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

&&

$$

SHORT TERM...HATTINGS
LONG TERM...WM
AVIATION...AEM
FIRE WEATHER...HATTINGS


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