Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 040927
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
327 AM MDT SAT JUL 4 2015

.SYNOPSIS...HIGH PRESSURE ALOFT ACROSS THE GREAT BASIN WILL
SETTLE INTO THE SOUTHERN ROCKIES LATER IN THE WEEKEND. ABUNDANT
MOISTURE ALONG WITH WEAK WEATHER DISTURBANCES MOVING THROUGH THE
REGION WILL GENERATE SHOWERS AND THUNDERSTORMS INTO EARLY NEXT
WEEK.

&&

.SHORT TERM (THROUGH 12Z TUESDAY)...
WATER VAPOR LOOP SHOWS THE RIDGE AXIS ALONG THE FOUR
CORNERS...PLACING RETURN FLOW OVER THE WESTERN GREAT BASIN AHEAD
OF A CLOSED LOW WELL OFF THE CALIFORNIA COAST. AMDAR 400-250MB
WIND OBSERVATIONS SHOW A 50-95KT NORTHWESTERLY JET FROM THE
PACIFIC NORTHWEST INTO THE PLAINS. A CYCLONIC JET WAS LOCATED
FROM THE EASTERN PACIFIC INTO CALIFORNIA. 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.

EXPECTING CONVECTION TO BECOME ORGANIZED TODAY BY AN IMPULSE RIDING
NORTHWEST FROM NORTHWEST ARIZONA. STORM MOTION IS MEAGER...DECENT
WARM RAIN CLOUD LAYER AND DEWPOINTS 55-60F ACROSS SOUTHWEST UTAH
ALONG WITH THE THREAT OF TRAINING. HOWEVER THERE IS COPIOUS CLOUD
COVER SO OPTED AGAINST A FLASH FLOOD WATCH. HAVE INSTEAD CARRIED A
MODERATE FLASH FLOOD POTENTIAL RATING FOR PORTIONS OF SOUTHERN
UTAH.

THIS ACTIVITY EXPECTED TO LIFT NORTHWARD THIS EVENING INTO THE
OVERNIGHT PERIOD. THOSE WITH OUTDOOR PLANS DEFINITELY NEED TO
CONSIDER THE POTENTIAL FOR CONVECTION. UP NORTH...WEATHER LIKELY
WONT BE TOO EXCITING UNTIL LATE AFTERNOON OR PERHAPS SUNSET.
CONVECTION LIFTING INTO NORTHERN UTAH WILL CARRY THE THREAT OF
LOCALLY GUSTY WINDS IN ADDITION TO CLOUD TO GROUND
LIGHTNING...SOMETHING TO KEEP IN MIND BEFORE HEADING OUT.

AFOREMENTIONED WAVE SHEARS OUT OVER THE IDAHO BORDER REGION SUNDAY.
THIS SHOULD PROVIDE THE FOCUS FOR CONVECTION AS DRYING ALOFT BEGINS
TO THIN OUT MORE DIURNAL ACTIVITY ACROSS SOUTHERN UTAH.

WITH HEIGHTS BUILDING BACK IN BEHIND THE DISTURBANCE SUNDAY NIGHT
BELIEVE CONVECTION WILL DECAY BY MONDAY MORNING. HOWEVER DIURNAL
CONVECTION IS EXPECTED TO REDEVELOP ACROSS THE REGION MONDAY
AFTERNOON AND EVENING GIVEN THE AMOUNT OF INSTABILITY IN PLACE UNDER
THE RIDGE.

THE INCREASE IN CLOUD COVER...AND A LITTLE MORE MOISTURE SHOULD TAKE
THE EDGE OFF OF TEMPERATURES DURING THE NEXT SEVERAL DAYS.

.LONG TERM (AFTER 12Z TUESDAY)...
THE RIDGE OVER THE GREAT BASIN CONTINUES TO WEAKEN MONDAY NIGHT
DUE TO STORM SYSTEMS CROSSING THE NORTHERN ROCKIES. A WEST-
SOUTHWEST FLOW OVER UTAH DOWNSTREAM OF A CLOSED LOW APPROACHING
THE CALIFORNIA COAST WILL RESULT IN A GRADUAL DRYING TREND.
HOWEVER...THE MONDAY NIGHT THROUGH TUESDAY TIMEFRAME COULD REMAIN
SOMEWHAT ACTIVE IN TERMS OF CONVECTION AS MODELS INDICATE A WEAK
DISTURBANCE CROSSING NORTHERN UTAH. OTHERWISE...THE DRYING TREND
FROM SOUTHWEST TO NORTHEAST WILL BE MORE NOTICEABLE FOR THE SECOND
HALF OF THE WEEK.

THE AFOREMENTIONED CLOSED LOW IS PROGGED BY THE GLOBAL MODELS TO
EJECT ACROSS THE GREAT BASIN FRIDAY THROUGH FRIDAY NIGHT...WEAKENING
AS IT RIDES NORTH AROUND THE RIDGE WHICH WILL STRENGTHEN AGAIN OVER
THE TEXAS PANHANDLE. THERE COULD BE SOME DYNAMIC FORCING OVER
NORTHWEST UTAH FRIDAY NIGHT AND SATURDAY WITH THE STORM GRAZING THE
AREA...BUT THE AIRMASS IS EXPECTED TO BE TOO DRY BY THIS POINT TO
ALLOW FOR MUCH IF ANY PRECIPITATION.

OTHERWISE...EXPECT SOUTHERLY WINDS TO INCREASE ACROSS THE AREA
COINCIDENT WITH THE APPROACH OF THE STORM. THESE STRONGER WINDS
COULD BEGIN AS EARLY AS WEDNESDAY ACROSS SOUTHWEST UTAH THEN BECOME
MORE WIDESPREAD HEADING INTO THE END OF THE WEEK. TEMPERATURES ARE
EXPECTED TO REMAIN CLOSE TO NORMAL THROUGHOUT THE PERIOD.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THIS
AFTERNOON AT THE SLC TERMINAL WITH OCCASIONAL CIGS WELL ABOVE
7000FT. SOUTH WINDS SHOULD TURN NORTHWEST BEGINNING BETWEEN 18-20Z.
AN INCREASING CHANCE OF SHOWERS AND LOWER CIGS IS EXPECTED LATE
EVENING AND CONTINUING OVERNIGHT.

&&

.FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
BE THE RULE THROUGH THE MIDDLE OF NEXT WEEK. NEW LIGHTNING STARTS
ARE THE PRIMARY CONCERN...WITH WETTING RAIN ONLY GRADUALLY
INCREASING IN COVERAGE DURING THE TIME PERIOD. THE INCREASE IN
CONVECTION WILL TREND TEMPERATURES DOWN A NOTCH AND HUMIDITY UP A
BIT.

AN ABRUPT PATTERN SHIFT IS CURRENTLY ADVERTISED DURING THE MIDDLE OF
NEXT WEEK. A DRY AND VERY GUSTY SOUTHWESTERLY FLOW DEVELOPS TRENDING
HUMIDITY LOWER. CONVECTION WILL STILL BE AROUND...THOUGH WETTING
RAIN BECOMES LESS OF A POSSIBILITY AS ACTIVITY BECOMES HIGHER
BASED.

&&

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

$$

SHORT TERM/FIRE WEATHER...ROGOWSKI
LONG TERM/AVIATION...CHENG

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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