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000
FXUS65 KSLC 121537
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
937 AM MDT SUN MAY 12 2013

.SYNOPSIS...A STRONG RIDGE ALOFT WILL BE DIRECTLY OVER THE GREAT
BASIN TODAY AND EARLY MONDAY. A WEAK COLD FRONT WILL MOVE INTO
NORTHERN UTAH MONDAY EVENING AND STALL ACROSS SOUTHERN UTAH ON
TUESDAY.

&&

.DISCUSSION...UPPER RIDGE AXIS AT 500 MB EXTENDS FROM ABOUT RENO
TO MISSOULA. THE RIDGE AXIS MAKES IT SLC THIS EVENING. WITH
PASSAGE OF UPPER RIDGE AXIS FLOW BACKS TO THE SOUTHWEST. WITH
SOUTHWEST FLOW ALOFT AND FAVORABLE SURFACE PRESSURE
GRADIENT...SOUTH WINDS WILL BLOW ON MONDAY ACROSS THE ENTIRE
FORECAST AREA.

12Z SOUNDING SHOWS SOMEWHAT WARMER AIRMASS THIS MORNING AT ALL
LEVELS COMPARED TO 24 HOURS AGO. EVEN WARMER AIR INDICATED IN
UPPER AIR SOUNDINGS UPSTREAM OVER ID/NV. EXPECT TODAY TO BE 2 TO 4
DEGREES WARMER THAN YESTERDAY STATEWIDE AND THEN WARMER STILL MONDAY WITH
SOME RECORD TEMPS LIKELY TO BE SET MONDAY WITH COMBO OF VERY WARM
AIRMASS AND GOOD MIXING IN THE SOUTHWEST FLOW.

COLD FRONT MONDAY NIGHT IN ALL MODEL RUNS WILL BRING SOME COOLING
TO THE NORTH ALTHOUGH TEMPS WILL STILL BE ABOVE AVERAGE. FRONT
WILL STALL ACROSS SOUTHERN UTAH AND THEN DISSIPATE IN PLACE MID WEEK.

THREAT OF PRECIP MINIMAL TODAY AND MONDAY...COULD BE ISOLATED
CONVECTION OVER THE UINTA MOUNTAINS AND THE HIGHER TERRAIN OF
SOUTHERN UTAH NEAR ESCALANTE/BOULDER. CURRENT FORECASTS HAVE ABOUT
10 TO 15 PERCENT POPS FOR THOSE AREAS AND THIS FITS CURRENT
THINKING FOR MEASURABLE RAIN...VIRGA AND GUSTY WINDS THE MAIN
IMPACT IF A SHOWER DOES FORM.

NO CHANGES TO CURRENT FORECASTS AT THIS TIME.

&&

.AVIATION...VFR CONDITIONS EXPECTED AT THE SLC TERMINAL THROUGH THE
TAF PERIOD. SOUTHEAST WINDS WILL CONTINUE THROUGH LATE MORNING OR
EARLY AFTERNOON BEFORE SHIFTING NORTHWEST. NORTHWEST WINDS LIKELY
REMAIN UNDER 8KT UNTIL AROUND 19Z...THEN SURPASS 8KT THRESHOLD.

&&

.FIRE WEATHER...A WARMING/DRYING TREND CONTINUES EARLY THIS WEEK AS
A RIDGE OF HIGH PRESSURE BUILDS IN. EXPECT SUMMER-LIKE TEMPERATURES
AND AFTERNOON VALLEY HUMIDITY LEVELS TO DROP TO 10-15%. OVERNIGHT
MOISTURE RECOVERIES WILL BECOME POOR IN THE NORMALLY DRIER VALLEYS
OF WESTERN AND SOUTHERN UTAH BEGINNING MONDAY.

A WEAK COLD FRONT WILL APPROACH THE REGION MONDAY...WITH SOUTHERLY
WINDS INCREASING ESPECIALLY ACROSS THE WEST DESERT. THESE WINDS WILL
COMBINE WITH LOW HUMIDITY TO LIKELY CREATE AT LEAST LOCALLY CRITICAL
FIRE WEATHER CONDITIONS ACROSS THE WEST...THOUGH FUELS ARE DEEMED AS
NOT CRITICAL AT THIS TIME. A COOL DOWN AND A SLIGHT INCREASE IN
HUMIDITY CAN BE EXPECTED MID WEEK WITH LOCALLY GUSTY WINDS BECOMING
WESTERLY BEHIND THE COLD FRONT. THIS COULD ALLOW LOCALLY CRITICAL
FIRE WEATHER CONDITIONS TO DEVELOP ACROSS EASTERN VALLEYS PRONE TO
DOWNSLOPE WINDS TUESDAY WITH MARGINAL HUMIDITY LEVELS...THOUGH
FUELS ARE DEEMED AS NOT CRITICAL AT THIS TIME. ANY CONVECTION IS
EXPECTED TO BE ISOLATED IN NATURE.

IN THE EXTENDED...THERE IS THE POTENTIAL FOR A STRONGER COLD FRONT
THURSDAY INTO FRIDAY WHICH COULD PROVIDE EVEN GUSTIER SOUTH WINDS
AND VERY LOW HUMIDITY LEVELS AHEAD OF THIS FEATURE. IT LOOKS LIKE A
STRONG WARNING POTENTIAL FROM A METEOROLOGICAL STANDPOINT WHERE
FUELS ARE DEEMED CRITICAL.

&&

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

$$

PUBLIC...DUNN
FIRE WEATHER/AVIATION..ROGOWSKI


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