Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 031548
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
948 AM MDT FRI JUL 3 2015

.SYNOPSIS...HIGH PRESSURE ALOFT ACROSS THE GREAT BASIN WILL REMAIN
IN PLACE TODAY BEFORE SLOWLY SHIFTING INTO THE SOUTHERN ROCKIES THIS
WEEKEND. INCREASING MOISTURE AND SOMEWHAT COOLER TEMPERATURES WILL
MOVE INTO THE REGION LATE IN THE WEEKEND THROUGH EARLY NEXT WEEK.

&&

.DISCUSSION...MORNING WATER VAPOR AND H5 ANALYSIS INDICATE
ELONGATED RIDGING ACROSS THE EASTERN GREAT BASIN STATES THIS
MORNING...WITH SHEAR AXIS STRETCHING FROM EASTERN NEVADA THROUGH
SOUTHEASTERN UTAH. SAID AXIS REMAINS A DELINEATION OF ELEVATED
PWAT TO THE SOUTH AND WEST...AND A VERY DRY AIRMASS TO THE NORTH
AND EAST. COPIOUS MID LEVEL CLOUD COVER AND SPOTTY SHOWERS
CURRENTLY EXIST BENEATH AND ALONG THIS ZONE AND ANTICIPATE THIS
AXIS /AND ESPECIALLY THE PERIPHERIES OF/ TO BE THE FOCUS FOR
INCREASED CONVECTION AS HEATING OF THE DAY ENSUES. PWATS ON THE
ORDER OF .9 TO 1 INCH ALONG THIS AXIS AND WEAK FLOW ALOFT SHOULD
PROMOTE ISOLATED TO WIDELY SCATTERED SLOW MOVING THUNDERSTORMS
DEVELOPING OVER THE TERRAIN AND ADJACENT VALLEYS FROM THE
SOUTHERN MTNS TO THE NEVADA BORDER LATE DAY. THE POTENTIAL FOR
LOCALIZED HEAVY RAIN DOES EXIST BUT IS NOT EXPECTED TO BE THE
NORM.

MODELS CONTINUE TO GRADUALLY LIFT THIS AXIS NORTH AND EAST
BEGINNING THIS AFTERNOON...THIS SPREADING THE CONVECTIVE
POTENTIAL NORTHEAST BY THIS EVENING. HAVE ADDED SLIGHT CHANCE POPS
NORTH ALONG OUR WESTERN BORDER TO ROUGHLY IBAPAH FOR THE AFTERNOON
HOURS AND INTO THE WEST DESERTS THIS EVENING. NO OTHER SIGNIFICANT
UPDATES TO NOTE IN THE SHORT TERM.

PREVIOUS DISCUSSION BELOW...

THE RIDGE IS STILL EXPECTED TO SHIFT OVERHEAD FOR TOMORROW. AS IT
DOES SO...MOISTURE WILL START TO INCREASE AGAIN INTO THE AREA. THIS
MOISTURE SURGE WILL CONTINUE INTO SUNDAY AS THE RIDGE AXIS SHIFTS
EAST. THIS WILL RESULT IN AN INCREASING TREND IN PRECIPITATION
ACROSS THE FORECAST AREA. ADDITIONALLY...MODELS CONTINUE TO INDICATE
A SHORTWAVE DISTURBANCE LIFTING ACROSS THE AREA TOMORROW NIGHT INTO
SUNDAY...SERVING AS A FOCUS FOR CONVECTION. THIS IS A FEATURE THAT
HAS BEEN RESOLVED IN THE MODELS FOR SEVERAL RUNS NOW...ALTHOUGH THE
00Z EC IS A BIT SLOWER WITH THIS WAVE NOW THAN THE 00Z GFS SO SOME
UNCERTAINTY STILL EXISTS.

THE RIDGE WILL FLATTEN...THEN PUMP UP SLIGHTLY OVER NEVADA ON MONDAY.
THE RIDGE AXIS IS THEN EXPECTED TO GRADUALLY MIGRATE EAST THROUGH
MIDWEEK AS A CLOSED LOW OFF THE WEST COAST MOVES INTO THE SF BAY
AREA. THE RESULTING SOUTHWEST/WESTERLY FLOW WILL GRADUALLY SPREAD
DRIER AIR INTO THE AREA FROM SOUTHWEST TO NORTHEAST DURING THIS
TIMEFRAME.

WITH THE INCREASE IN MOISTURE AND THE ASSOCIATED CLOUDS AND
PRECIPITATION...TEMPERATURES WILL SEE A CORRESPONDING DROP LATE THIS
WEEKEND AND INTO THE EARLY PART OF NEXT WEEK. HOWEVER...THE
TEMPERATURES ARE NOT EXPECTED TO RECOVER TOO MUCH BY MIDWEEK WITH
THE DRIER AIR DUE TO THE WEAKENING OF THE RIDGE.

&&

.AVIATION...OPERATIONAL WEATHER CONCERNS WILL REMAIN MINIMAL AT
THE KSLC TERMINAL THROUGH THE VALID TAF PERIOD. SOUTHEAST SURFACE
WINDS ARE EXPECTED TO BECOME A PREVAILING NORTHWESTERLY BETWEEN
17-19Z PER NORM.

&&

.FIRE WEATHER...HIGH PRESSURE OVER THE GREAT BASIN WILL KEEP A HOT
AIRMASS ACROSS THE DISTRICT TODAY WITH SLIGHT COOLING SATURDAY.
MOISTURE WILL REMAIN IN PLACE ACROSS SOUTHERN UTAH TODAY WITH A
CHANCE OF SHOWERS AND THUNDERSTORMS. LOW AFTERNOON HUMIDITY WILL
PERSIST ACROSS THE CENTRAL AND NORTHERN VALLEYS TODAY WITH ONLY
ISOLATED MOUNTAIN THUNDERSTORMS POSSIBLE. THE MOISTURE THEN WILL
SPREAD NORTH SATURDAY THROUGH SUNDAY AS THE HIGH SHIFTS EAST. THIS
WILL BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE
WEEKEND. HIGHER HUMIDITY AND AN INCREASING CHANCE OF WETTING RAINS
WILL ALSO ACCOMPANY THE MOISTURE INCREASE ALONG WITH A COOLING
TREND. MOISTURE WILL CONTINUE OVER THE DISTRICT MONDAY INTO TUESDAY.

A DRIER SOUTHWEST FLOW IS FORECAST TO BEGIN TO SPREAD INTO THE GREAT
BASIN AROUND MIDWEEK BRINGING A DRYING TREND FOR THE LATTER PART OF
THE WEEK ALONG WITH LOCAL GUSTY SOUTHWEST WINDS.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&

$$

DISCUSSION...MERRILL
PREVIOUS DISCUSSION...CHENG/WILENSKY


FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)



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