Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 031733
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1133 AM MDT FRI JUL 3 2015

.SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT

AS FOR THE WEATHER TODAY AS WE HEAD INTO THE HOLIDAY WEEKEND IT
LOOKS LIKE A CARBON COPY OF THE PREVIOUS FEW DAYS. WAIT THIS IS
2015...MAYBE I SHOULD HAVE SAID PHOTOCOPY OR PDF. ANYWAY...WITH THE
RIDGE CONTINUING TO BE IN PLACE OVER THE AREA LOOK FOR ANOTHER VERY
WARM DAY ACROSS THE COUNTY WARNING AREA. AND...LIKE IN PREVIOUS
DAYS...ANOTHER SHORTWAVE...THIS ONE MOVING IN FROM NORTHERN
IDAHO...WILL BRUSH BY CLOSE ENOUGH TO THE AREA TO THE AREA TO BRING
ANOTHER ROUND OF MAINLY HIGHER ELEVATION THUNDERSTORMS IN THE
AFTERNOON AND EVENING HOURS. LIKE PREVIOUS DAYS...A FEW MAY MOVE OFF
OF THE MOUNTAINS BUT WITH WEAK STEERING FLOW MOST AREAS IN THE LOWER
ELEVATIONS SHOULD REMAIN RAIN FREE. TEMPERATURES SHOULD BE A FEW
DEGREES WARMER THAN YESTERDAY.

AS WE HEAD INTO INDEPENDENCE DAY...IT STILL LOOKS TO BE HOT AS A
FIRECRACKER ACROSS THE AREA AS THE RIDGE REACHES IT`S PEAK STRENGTH
ACROSS THE COWBOY STATE. THIS MEANS THAT IT WILL BE THE WARMEST DAY
WITH MOST OF THE LOWER ELEVATIONS RISING INTO THE 90S. ALSO...WITH
THE STRENGTH OF THE RIDGE...THIS WILL LIMIT THE COVERAGE OF THE
NATURES FIREWORKS IN THE FORM OF THUNDERSTORMS. THESE SHOULD BE
LIMITED TO THE HIGHEST ELEVATIONS WITH THE HIGH ELEVATION HEAT
SOURCE. HOWEVER...GET READY FOR A BIG CHANGE IN THE WEATHER AS WE
HEAD INTO SUNDAY.

A STRONG COLD FRONT WILL DROP SOUTHWARD ACROSS THE STATE DURING
SUNDAY AND USHER IN MUCH COOLER TEMPERATURES. THE NEW GFS MOS
ACTUALLY LOWERS HIGH TEMPERATURES INTO THE 60S ACROSS MANY OF THE
LOWER ELEVATION LOCATIONS. THIS MAY BE OVERDONE...BUT MANY AREAS
COULD SEE HIGH TEMPERATURES 20 DEGREES COOLER THAN ON SATURDAY. IN
ADDITION...WITH PRECIPITABLE WATER VALUES CLIMBING TO OVER 1 INCH
ACROSS MUCH OF THE AREA THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL
CLIMB AS WELL. HOWEVER...THERE IS THE QUESTION OF HOW STRONG THE
THUNDERSTORMS WILL BE. A LOT DEPENDS ON HOW MUCH INSTABILITY THERE
IS. AND NOW BOTH THE NAM AND GFS HAVE FAIRLY LIMITED INSTABILITY
WITH LIFTED INDICES NEAR ZERO OR EVEN SLIGHTLY POSITIVE AND LIMITED
CAPE. FOR NOW...WE WILL KEEP THUNDERSTORMS IN THE FORECAST. BUT THE
BIG STORY THAT DAY WILL BE FOR MUCH COOLER TEMPERATURES THAN THERE
HAVE BEEN SEEN FOR THE PAST COUPLE OF WEEKS.

.LONG TERM...MONDAY THROUGH FRIDAY

NW FLOW ALOFT FOR MONDAY. BEST CHANCE OF SHOWERS AND STORMS WILL BE
ALONG AND WEST OF THE DIVIDE INTO MONDAY NIGHT. ACTIVITY EAST OF THE
DIVIDE LOOKS TO BE MONDAY EVENING INTO LATE MONDAY NIGHT. ON TUESDAY
THE LONG RANGE MODELS HINT AT A WEAK WEATHER DISTURBANCE MOVING
THROUGH THE REGION. THIS WOULD BRING A CHANCE OF SHOWERS AND STORMS
TO THE AREA DURING THE AFTERNOON AND EVENING. ANOTHER WEATHER SYSTEM
IN A NW FLOW ALOFT LOOKS TO IMPACT THE REGION WED AFTERNOON AND
NIGHT. THE GFS MODEL IS SLOWER WITH TIMING AND THE ECMWF MODEL IS
FASTER. AGAIN THIS WOULD BRING A DECENT CHANCE OF SHOWERS AND STORMS
TO THE REGION WED PM AND NIGHT. THURSDAY ALSO LOOKS UNSETTLED WITH
LINGERING MOISTURE OVER THE AREA. WILL KEEP SLIGHT CHANCE IN THE
FORECAST. NEXT FRIDAY WILL BE MOSTLY DRY WITH ONLY ISOLATED SHOWERS
OR STORMS. TEMPS WILL BE MILD TO WARM MONDAY...THEN WARMER TUE. WED
WILL BE WARM AS WELL BUT HAVE BROUGHT SLIGHT COOLING INTO THE NORTH
AS THAT WEATHER SYSTEM APPROACHES. 700MB TEMPS REBOUND QUICKLY NEXT
THURS AND FRI WHICH BRINGS WARM TO HOT CONDITIONS TO THE REGION.&&

.AVIATION.../18Z ISSUANCE/

AN UPPER LEVEL DISTURBANCE WILL PUSH SE ACROSS NORTHERN WYOMING
TODAY. SOME ISOLD -SHRA WILL MOVE INTO NW WYOMING 18Z - 20Z THEN
EXPECT ISOLD-WDLY SCT -TSRAGS MAINLY VCNTY AND NORTH OF A KJAC-
KLND-KCPR LINE IN THE AFTERNOON...WITH DRIER AND MORE STABLE
CONDITIONS TO THE SOUTH. BRIEF MVFR CONDITIONS WILL BE POSSIBLE
WITH ANY STORMS. MOST OF THIS ACTIVITY WILL CLEAR THE AREA OR
DISSIPATE WITH SUNSET...WITH SKC-FEW FL150-200 PREVAILING AFTER
06Z SATURDAY.

.FIRE WEATHER...

WITH HIGH PRESSURE OVER THE NORTHERN PLAINS...AND LOW PRESSURE OVER
THE GREAT BASIN...LOW LEVEL NORTHEAST FLOW EXTENDS ACROSS THE AREA.
MOST OF THE BASINS HAVE LIMITED MOISTURE.  OVER AND NEAR THE
CONTINENTAL DIVIDE...AND THE BIGHORN MOUNTAINS...ENOUGH MOISTURE AND
INSTABILITY EXISTS FOR AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS. TEMPERATURES WILL BE COOLER OVER THE NORTH AND EAST
WITH WARMER TEMPERATURES OVER THE SOUTHWEST. A MAJOR CHANGE WILL
MOVE IN FOR SUNDAY AS A COLD FRONT BRINGS COOLER TEMPERATURES AND A
BETTER CHANCE OF SHOWERS.&&

&&

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

$$

SHORT TERM...HATTINGS
LONG TERM...AR
AVIATION...C.BAKER
FIRE WEATHER...HATTINGS



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