Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 020201
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
801 PM MDT WED JUL 1 2015

.SYNOPSIS...HIGH PRESSURE ALOFT CENTERED ACROSS THE WESTERN GREAT
BASIN WILL SHIFT EAST TO THE FOUR CORNERS THIS WEEKEND. A GRADUAL
DRYING TREND CAN BE EXPECTED THROUGH THE END OF THE WORK WEEK...THEN
INCREASING MOISTURE AND SOMEWHAT COOLER TEMPERATURES WILL MOVE INTO
THE REGION FOR EARLY NEXT WEEK.

&&

.DISCUSSION...WATER VAPOR LOOP SHOWS A RIDGE ELONGATING
NORTHWEST INTO CENTRAL NEVADA FROM THE FOUR CORNERS. AMDAR
400-250MB WIND OBSERVATIONS SHOW A 75-90KT NORTHWESERLY JET FROM
ALONG THE NORTHERN ROCKIES INTO THE UPPER PLAINS. GOES/GPS/RAP/00Z
SLC RAOB INDICATE THE PRECIPITABLE WATER VALUE RANGES BETWEEN
0.45" NORTHEAST MOUNTAINS...TO 1.00"- 1.40" ACROSS MOST VALLEYS.

GOING FORECAST IS IN GOOD SHAPE. COMBINATION OF SUBSIDENCE AND
DRYING NORTHWEST FLOW ALOFT KEPT MUCH ACTIVITY FROM GETTING GOING
ACROSS THE NORTH. HAVE EXPANDED MENTION OF ISOLATED CONVECTION TO
MOST OF SOUTHERN AND WEST CENTRAL UTAH OVERNIGHT PER RADAR TRENDS
AND LAST SEVERAL RUNS OF THE HRRR-3KM.

OTHERWISE UTILIZED COMBINATION OF PERSISTENCE AND LAMP GUIDANCE FOR
THE TEMPERATURE/DEWPOINT CURVE OVERNIGHT.

&&

PREVIOUS DISCUSSION...

HIGH PRESSURE REMAINS OVER THE GREAT BASIN THIS AFTERNOON...WITH THE
RIDGE AXIS OVER NEVADA. A RELATIVELY MOIST AIRMASS REMAINS OVER UTAH
AND SOUTHWEST WYOMING WITH PWS AROUND 1.0 INCH. THE REPOSITIONING OF
THE RIDGE AXIS HAS PUT THE AREA UNDER A MORE N/NW FLOW...AND THIS IS
ALLOWING DRIER AIR TO START TO NOSE IN FROM THE NORTH. STILL...WITH
DECENT MOISTURE IN PLACE SHOWERS AND THUNDERSTORMS HAVE STARTED
DEVELOPING OVER THE HIGHER TERRAIN...THOUGH COVERAGE IS A BIT LESS
THAN YESTERDAY. STILL THINK DEVELOPMENT WILL CONTINUE INTO THE EARLY
EVENING SO HAVE NOT CHANGED POPS MUCH. MAXES ALSO RUNNING A LITTLE
BIT COOLER TODAY COMPARED TO YESTERDAY BUT STILL 5-10F ABOVE
SEASONAL NORMS.

DRIER AIR WILL CONTINUE TO MAKE ITS WAY INTO THE AREA THURSDAY AND
FRIDAY IN NORTHWESTERLY FLOW AS THE RIDGE AXIS MOVES SLOWLY EAST.
BECAUSE OF THIS...COVERAGE OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WILL CONTINUE TO DECREASE. BY SATURDAY...THE RIDGE
AXIS MOVES OVERHEAD SO LITTLE CHANGE IN MOISTURE IS EXPECTED...BUT
MAXES SHOULD START TO WARM AGAIN WITH 100F POSSIBLE AGAIN ALONG THE
WASATCH FRONT.

GLOBAL MODELS INDICATE RIDGE AXIS WILL BE EAST OF THE FORECAST AREA
BY SUNDAY...AND THE FLOW ALOFT WILL SWITCH TO S/SW. THIS WILL DRAW
TROPICAL MOISTURE BACK INTO THE FORECAST AREA...INCREASING CHANCES
FOR CONVECTION WHILE BRINGING TEMPERATURES CLOSER TO SEASONAL
NORMALS. THOUGH GUIDANCE YESTERDAY INDICATED THIS MOISTURE WOULD BE
SHORT LIVED...GFS/EC TODAY ARE BACK TO HOLDING ONTO THIS MOISTURE
THROUGH EARLY NEXT WEEK. CURRENT POPS COVER THE TREND WELL AND DID
NOT MAKE MANY CHANGES IN THE EXTENDED PERIOD.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT KSLC THROUGH THE TAF
PERIOD. NORTHWEST WINDS WILL BECOME LIGHT/VARIABLE OR SWITCH TO
THE SOUTHEAST BETWEEN 04Z-06Z.

&&

.FIRE WEATHER...THE UPPER RIDGE CENTERED NEAR THE UTAH/NEVADA BORDER
THIS AFTERNOON WILL SLOWLY SHIFT EAST THE NEXT SEVERAL DAYS...ENDING
UP NEAR THE FOUR CORNERS REGION BY EARLY NEXT WEEK. SOMEWHAT DRIER
AIR WORKING SOUTH ACROSS THE STATE TONIGHT THROUGH THURSDAY WILL
SERVE TO REDUCE THE AFTERNOON/EVENING CONVECTION. ENOUGH RESIDUAL
MOISTURE WILL STILL EXIST FOR ISOLATED TERRAIN-BASED CONVECTION
THROUGH SATURDAY.

THE RECENTERING OF THE UPPER RIDGE NEAR THE FOUR CORNERS WILL ALLOW
MOISTURE TO RETURN NORTH INTO THE REGION LATE SUNDAY/MONDAY. SHOWERS
AND THUNDERSTORMS WILL BEGIN TO INCREASE IN AREAL COVERAGE SUNDAY
AFTERNOON...THEN PEAK ON MONDAY/MONDAY NIGHT.

TEMPERATURES WILL REMAIN ABOVE TO WELL ABOVE EARLY JULY NORMALS
WITH  RH VALUES LOW THROUGH THE UPCOMING WEEKEND. INCREASED
CONVECTIVE PRECIP EARLY NEXT WEEK WILL LEAD TO COOLER MORE
SEASONAL TEMPERATURES EARLY IN THE WEEK...WITH HIGHER RH VALUES AND
BETTER NIGHT TIME RECOVERIES.

&&

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

$$

PUBLIC...ROGOWSKI/TRAPHAGAN
FIRE WEATHER...CONGER
AVIATION...ROGOWSKI

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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