Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 291026
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
426 AM MDT SAT AUG 29 2015

.SYNOPSIS...AS A RIDGE OF HIGH PRESSURE OVER THE GREAT BASIN
SHIFTS EAST TODAY...MOISTURE WILL SPREAD NORTHWARD INTO THE
REGION. A WEAK COLD FRONT WILL SLIDE INTO NORTHERN UTAH TONIGHT
AND THEN TO SOUTHERN UTAH ON SUNDAY. A GENERALLY DRY
SOUTHWESTERLY FLOW WILL PREVAIL THIS UPCOMING WORKWEEK.

&&

.SHORT TERM (THROUGH 12Z TUESDAY)...WARM AND DRY CONDITIONS CONTINUE
ACROSS MUCH OF UTAH AND SOUTHWEST WYOMING THIS MORNING...AS
SOUTHWESTERLY FLOW INCREASES OUT AHEAD OF A TROUGH OVER THE PACIFIC
NORTHWEST. INCREASING CLOUD COVER AND SOME LIGHT SHOWER ACTIVITY
HAVE BOTH BEGUN ACROSS FAR NORTHWESTERN UTAH...AND THAT IS WHERE THE
BEST SHOWER AND THUNDERSTORM ACTIVITY MAY BE THIS AFTERNOON...WITH
INCREASING UNIDIRECTIONAL SHEAR AND SYNOPTIC SCALE FORCING NEAR THE
LOW LEVEL BAROCLINIC ZONE. MORE ISOLATED ACTIVITY IS ALSO POSSIBLE
IN WESTERN AND SOUTHERN UTAH...AS WELL AS ALONG MOST OF THE HIGHER
TERRAIN...AS MOISTURE INCREASES OVER THE AREA FROM THE SOUTH.

OTHERWISE...TODAY SHOULD BE A BREEZY AND HOT DAY ACROSS MUCH OF THE
AREA...WITH TEMPERATURES GENERALLY RUNNING 10 DEGREES FAHRENHEIT
WARMER THAN TYPICAL ACROSS THE NORTH AND 5 DEGREES ABOVE CLIMO
ACROSS THE SOUTH. THE STRONGEST WINDS SHOULD BE IN THE NORTHWEST
PORTIONS OF UTAH...BUT GENERALLY LOOK TO REMAIN BELOW ADVISORY
CRITERIA AT THIS TIME.

THE LOW LEVEL BAROCLINIC ZONE WILL PUSH ACROSS NORTHERN UTAH IN
THE EVENING AND OVERNIGHT HOURS...AND THAT PERIOD LOOKS LIKE THE
BEST CHANCE FOR PRECIPITATION ACROSS THE WASATCH FRONT AND NEAR
THE IDAHO BORDER. HAVE INCREASED POPS FOR THE 00Z-06Z SUNDAY TIME
FRAME...AND THESE POPS STILL MAY NOT BE HIGH ENOUGH...ESPECIALLY
NEAR THE NORTHERN BORDER. TIME OF DAY AND THE RELATIVELY
WEAK/SHALLOW NATURE OF THE FORCING WILL BE LIMITING FACTORS...BUT
STILL THINK AT LEAST SOME INCREASE IN CLOUD COVER AND SHOWER
COVERAGE IS TO BE EXPECTED AS THIS FEATURE CROSSES THE AREA.

THE SHORTWAVE TROUGH CONTINUES TO SWING ACROSS THE GREAT BASIN AND
INTERMOUNTAIN WEST ON SUNDAY AND SUNDAY NIGHT. THIS FORCING LOOKS TO
INTERSECT WITH THE BEST MOISTURE TAP ACROSS THE EASTERN HALF OF UTAH
THROUGH THE DAY SUNDAY...AND HAVE INCREASED POPS FOR SUNDAY
AFTERNOON AND EVENING. THE COLD FRONT SWINGING THROUGH WILL LOWER
TEMPS A FAIR AMOUNT COMPARED TO SATURDAY...BUT IN GENERAL SHOULD
ONLY PUSH TEMPS TO NEAR NORMAL IN MOST LOCATIONS...PERHAPS A BIT
BELOW NORMAL IN THE CLOUDIER EASTERN PORTIONS OF THE FORECAST
AREA.

BEHIND THE SHORTWAVE...SIGNIFICANTLY DRIER AIR LOOKS TO MOVE INTO
THE CWA FROM THE WEST LATE SUNDAY THROUGH MONDAY...WITH A MILD ZONAL
FLOW SETTLING OVER THE AREA. WINDS BEGIN TO BACK A BIT HEADING INTO
TUESDAY NIGHT...AS THE NEXT TROUGH STARTS DIGGING INTO THE PACIFIC
NORTHWEST.

.LONG TERM (AFTER 12Z TUESDAY)...GFS AND ECMWF INDICATE A LOW
PRESSURE SYSTEM OFF THE PACIFIC NORTHWEST COAST TO DIG SOUTH TO
NORTHERN CALIFORNIA BY FRIDAY MORNING. MEANWHILE...THE RIDGE OF
HIGH PRESSURE FROM THE CENTRAL PLAINS TO THE SOUTHERN REACHES
OF ARIZONA AND NEW MEXICO WILL SLIDE TO THE EAST. THIS PATTERN
WILL PROMOTE A GENERALLY DRY...BUT BREEZY...SOUTHWEST FLOW ACROSS
THE GREAT BASIN. MAY BE ENOUGH RESIDUAL MOISTURE FOR ISOLATED
SHOWERS AND THUNDERSTORMS OVER HIGHER TERRAIN OF EAST CENTRAL AND
SOUTHEAST UTAH ON TUESDAY...OTHERWISE...DRY WEATHER SHOULD PREVAIL
THROUGH FRIDAY.

UPPER TROUGH WILL LIFT NORTHEAST...SCRAPING ACROSS NORTHERN
SECTIONS OF GREAT BASIN ON SATURDAY...WITH AN ASSOCIATED COLD
FRONT DROPPING INTO REGION. WITH ENSEMBLE SOLUTIONS SUPPORTING
DETERMINISTIC MODELS...CONFIDENCE REASONABLY HIGH. WHILE SYSTEM
LOOKS TO HAVE LIMITED MOISTURE TO WORK WITH...ESPECIALLY IN DRIER
GFS SOLUTION...DYNAMICS SUPPORT A SLIGHT CHANCE FOR SHOWERS AND
THUNDERSTORMS ACROSS AT LEAST HIGHER TERRAIN OF NORTHERN UTAH AND
SOUTHWEST WYOMING.

&&

.AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN FROM
THE SOUTH THROUGH MUCH OF TODAY...THOUGH THERE IS STILL A 10 PERCENT
CHANCE OF A SWITCH TO NORTHWEST WINDS BETWEEN 22Z AND 00Z...AS
TEMPERATURES APPROACH 100 DEGREES. THERE IS ALSO A 60 PERCENT CHANCE
OF WIND GUSTS EXCEEDING 30 MPH IN THE LATE MORNING OR AFTERNOON. THE
BEST SHOWER AND THUNDERSTORM ACTIVITY WILL LIKELY REMAIN WELL
NORTHWEST OF THE TERMINAL THROUGH 00Z...WITH AN INCREASING CHANCE OF
THUNDERSTORM IMPACTS AFTER 00Z.

&&

.FIRE WEATHER...SOUTHWESTERLY WINDS WILL INCREASE ACROSS UTAH TODAY
OUT AHEAD OF AN APPROACHING COLD FRONT...WITH THE STRONGEST WINDS IN
NORTHWESTERN UTAH. SHOWER AND THUNDERSTORM DEVELOPMENT IS POSSIBLE
AGAIN THIS AFTERNOON...PARTICULARLY IN THE WESTERN HALF OF
UTAH...WITH THE BEST COVERAGE OF SHOWERS ACROSS NORTHERN UTAH AS THE
WAVE PASSES THROUGH THE AREA THIS EVENING. THIS STORM SYSTEM WILL
CONTINUE TO PUSH THROUGH THE STATE ON SUNDAY...WITH THE MOST SHOWERS
EXPECTED ACROSS THE EASTERN HALF OF UTAH. AFTER THIS WAVE PASSES...A
DRIER AIR MASS WILL MOVE INTO THE AREA FOR THE BEGINNING OF THE
WORK WEEK...WITH INCREASING SOUTHWESTERLY WINDS TUESDAY ONWARD.

ISOLATED CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE TODAY...BUT
THE STRONGEST WINDS AND DRIEST CONDITIONS DO NOT LOOK TO LINE UP
WITH THE AREAS WHERE FUELS ARE CRITICALLY DRY. MORE CRITICAL
CONDITIONS MAY BE POSSIBLE DURING THE MIDDLE AND END OF NEXT WEEK.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...WY...RED FLAG WARNING FROM 11 AM MDT SATURDAY UNTIL 9 PM MDT
THIS EVENING WYZ277.

&&

$$

PUBLIC...SCHOENING/BARJENBRUCH
AVIATION...SCHOENING
FIRE WEATHER...SCHOENING

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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