Area Forecast Discussion
Issued by NWS Riverton, WY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 50

000
FXUS65 KRIW 280832
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 AM MDT TUE JUL 28 2015

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT

THE LARGE LOW PRESSURE SYSTEM THAT SIGNIFICANTLY IMPACTED THE
STATE OVER THE PAST 24 HOURS WILL CONTINUE TO FILL AND LIFT NORTH
THROUGH THE MORNING...AND WILL THEN TRACK EAST. COOL AIR ON THE
BACK SIDE OF THE LOW WILL CONTINUE TO FILTER INTO THE REGION TODAY
WITH HIGH TEMPERATURES 20 DEGREES COOLER IN SOME PLACES TODAY WHEN
COMPARED TO YESTERDAY. HOWEVER...HEIGHTS WILL BUILD THROUGH THE
DAY AND THE AIRMASS WILL GRADUALLY TEMPER THROUGH THE NIGHT WITH
MORE NORMAL TEMPERATURES RETURNING FOR WEDNESDAY AND THURSDAY. THE
AIRMASS WILL BE FAIRLY DRY AS WELL WITH NO PRECIPITATION WORTH
MENTIONING. WINDS WILL BE MUCH LIGHTER TOO WITH ONLY A FEW 25 MPH
BREEZES LINGERING THROUGH THE EARLY AFTERNOON ACROSS THE NORTH AS
OUR STORM LIFTS AWAY.

.LONG TERM...FRIDAY THROUGH TUESDAY

SYNOPSIS...UPPER LEVEL HIGH PRESSURE WILL BECOME ESTABLISHED OVER
THE FOUR CORNERS REGION THROUGH THE PERIOD BRINGING MAINLY DRY
WEATHER AND ABOVE NORMAL TEMPERATURES. SOME MID AND HIGH MONSOONAL
MOISTURE WILL BRING SLIGHT CHANCES OF THUNDERSTORMS TO THE
NORTH OVER THE WEEKEND AND INTO THE WEST EARLY NEXT WEEK.

DISCUSSION...THE MOST CONSISTENT SOLUTION DURING THIS PERIOD HAS
BEEN A STRONG UPPER LEVEL HIGH SETTING UP OVER THE FOUR CORNERS
REGION...WHILE KEEPING THE NORTHERN STREAM STORM TRACK AND
ASSOCIATED COLD FRONTS NORTH OF THE AREA. GFS IS THE MOST
CONSISTENT WITH THIS OVERALL SETUP THOUGH THE PERIOD WHILE ECMWF
BEGINS TO LOWER HEIGHTS ACROSS THE NORTHERN ROCKIES ON MONDAY AND
TUESDAY. FORECAST GIVES MORE WEIGHT GFS AND CONSISTENCY. H5
HEIGHTS WILL AVERAGE 590-594DM THROUGH THE PERIOD...H7 TEMPS FROM
AROUND 14C IN THE NE TO 18C IN THE SW. THIS WILL TRANSLATE INTO
LOWER TO MID 90S ACROSS THE LOWER CENTRAL BASINS WITH 80S ACROSS
THE WESTERN VALLEYS. A VERY DRY AIRMASS WILL REMAIN OVER THE AREA
ON FRIDAY WITH SOME MID AND HIGH LEVEL MONSOONAL MOISTURE
BEGINNING TO WRAP AROUND THE NORTHERN PERIPHERY OF THE FOUR
CORNERS HIGH ACROSS NORTHERN WYOMING OVER THE WEEKEND. THIS WILL
BRING A FEW HIGH-BASED STORMS MOSTLY ALONG FAVORED MOUNTAIN/VALLEY
CONVERGENCE AREAS. THIS IS THE TIME OF YEAR THE SW MONSOON USUALLY MAKES
A SURGE NORTHWARD...55-PLUS DEWPOINTS AND ALL. HOWEVER...55F
DEGREE ISODROSOTHERM WILL REMAIN WELL SOUTH ACROSS SOUTHERN NEVADA
AND ARIZONA WITH LITTLE DEWPOINT RECOVERY ACROSS
WYOMING...AVERAGING IN THE 30S. THUS...STORMS THAT DO DEVELOP WILL
BE MORE EFFICIENT WIND PRODUCERS WITH LITTLE RAIN.

&&

.AVIATION.../12Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH 12Z WEDNESDAY. A BREEZE WILL
DEVELOP ONCE AGAIN AFTER 16Z TUESDAY ACROSS THE SOUTHWESTERN WIND
CORRIDOR FROM KRKS TO KCPR AND NEAR KRIW...BUT WILL NOT BE AS STRONG
AS ON MONDAY. EXPECT SKC FOR MOST AREAS FOR MOST OF TOMORROW. WIND
WILL DROP UNDER 10 KNOTS FOR ALL TAF SITES AFTER 02Z WEDNESDAY AND
CONTINUE THROUGH THE NIGHT.

&&

.FIRE WEATHER...

REMAINING DRY TODAY...ESPECIALLY ACROSS SOUTHERN WYOMING WHERE
MINIMUM RELATIVE HUMIDITIES COULD DROP INTO THE LOW TEENS. HOWEVER
IT WILL BE MUCH COOLER WITH LIGHTER WINDS...A FEW 25 MPH GUSTS
WILL LINGER ACROSS NORTHERN WYOMING INTO THE EARLY AFTERNOON BUT
NO WIDESPREAD DANGEROUS CONDITIONS WILL EXIST. WARMER ON WEDNESDAY
AND THURSDAY AND REMAINING DRY WITH LOW HUMIDITY SPREADING
FURTHER NORTH...HOWEVER WINDS WILL BE LIGHT. NO SIGNIFICANT
PRECIPITATION OR HIGH WIND EVENTS ARE EXPECTED THROUGH THE
WEEKEND.

&&

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

$$

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



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