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000
FXUS65 KSLC 122101
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
301 PM MDT SUN MAY 12 2013

.SYNOPSIS...A RIDGE ALOFT OVER THE AREA THIS AFTERNOON WILL
FLATTEN MONDAY AS AN UPPER TROUGH MOVES THROUGH THE NORTHERN
ROCKIES. A WEAK COLD FRONT WILL PUSH SOUTH INTO UTAH MONDAY
EVENING AND STALL OVER SOUTH CENTRAL UTAH TUESDAY.

&&

.DISCUSSION...QUITE A STRETCH OF WARM AND DRY WEATHER AHEAD
THROUGH MUCH OF THE NEXT WEEK...THEN A POSSIBLE PATTERN CHANGE
NEXT WEEKEND.

UPPER RIDGE OVER THE AREA WILL GRADUALLY SHIFT
SLIGHTLY EAST AND FLATTEN AS UPPER TROUGH CURRENTLY IN THE EAST
PACIFIC MOVES THROUGH THE NORTHERN ROCKIES MONDAY/TUESDAY.

AIRMASS WILL BE SOMEWHAT WARMER MONDAY THAN TODAY AND STRONGER
SOUTHWEST FLOW ALOFT AND MORE FAVORABLE SURFACE PRESSURE GRADIENT
WILL BRING MORE SOUTHWEST FLOW AND MIXING. THUS EXPECTING NEAR OR
RECORD MAX TEMPS FOR MANY LOCATIONS MONDAY.

COLD FRONT WILL BE DRY AS IT MOVES INTO NORTHWEST UTAH MONDAY
EVENING AND STALLS ACROSS SOUTH CENTRAL UTAH ON TUESDAY. TEMPS
WILL FALL ABOUT 5 TO 7 DEGREES TUESDAY COMPARED TO MONDAY OVER THE
NORTH WITH LITTLE CHANGE OVER THE SOUTH.

ISOLATED CONVECTION POSSIBLE EACH OF THE NEXT FEW AFTERNOONS OVER THE
UINTAS AND SOME OF THE HIGHER TERRAIN OF SOUTHERN UTAH...BUT
MAINLY VIRGA...LIGHTNING...AND GUSTY WINDS RATHER THAN RAIN. MOST
ACTIVE REGION MAY BE CENTRAL UTAH IN VICINITY OF OLD FRONT
TUE/WED.

THE PATTERN RESETS WED/THU AS ANOTHER TROUGH APPROACHES FOR A
FRONTAL PASSAGE THURSDAY NIGHT...SO A BIT OF WARMING
WEDNESDAY...THEN SOUTH WINDS AND EVEN MORE WARMING THURSDAY.

WHILE BOTH EC/GFS HAVE SIMILAR TROUGH MOVING THROUGH ON
FRIDAY...AND BOTH SHOW OVERALL PATTERN SHIFT WITH TROUGHING
DEVELOPING OVER THE WEST...DETAILS BEGIN TO DIVERGE WITH EC
BRINGING A SERIES OF TROUGHS THROUGH THE AREA QUICKLY ON THE HEALS
OF THE FRIDAY TROUGH WHILE THE GFS BRINGS A SHORT WAVE RIDGE OVER
THE AREA OVER THE WEEKEND. RESULT IS THE EC IS COOLER WITH A
HIGHER THREAT OF PRECIP THAN GFS. THIS EC RUN IS QUITE A BIT MORE
AGGRESSIVE THAN PREVIOUS RUNS...SO POPS ARE CURRENTLY BASED ON GFS
SOLUTION WITH TEMPS A COMPROMISE BETWEEN THE GFS AND EC.

LOOKS LIKE A LARGE SCALE PATTERN CHANGE IN BOTH MODELS WITH A RETURN TO
MORE SEASONABLE TEMPS WITH A CHANCE OF PRECIP BEGINNING NEXT
WEEKEND INTO THE FOLLOWING WEEK.

&&

.AVIATION...NORTHWESTERLY SURFACE WINDS GREATER THAN 7 KNOTS WILL
REMAIN IN PLACE AT THE KSLC TERMINAL THROUGH 02-03Z BEFORE
DISSIPATING. THEREAFTER SURFACE WINDS WILL RETURN TO SOUTHEASTERLY
BETWEEN 03-04Z...GRADUALLY INCREASING LATE TONIGHT AND TOMORROW
MORNING. VFR CONDITIONS ARE EXPECTED TO BE MAINTAINED THROUGH THE
VALID TAF PERIOD.

&&

.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
STRONG WARNING POTENTIAL FROM A METEOROLOGICAL STANDPOINT WHERE
FUELS ARE DEEMED CRITICAL.

&&

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

$$

PUBLIC...DUNN
FIRE WEATHER...ROGOWSKI
AVIATION...MERRILL

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)