000
FXUS65 KSLC 130630 AAA
AFDSLC

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1230 AM MDT THU JUN 13 2013

.SYNOPSIS...A WARM AND DRY SOUTHWEST FLOW WILL CONTINUE INTO
THURSDAY. A DRY BUT FAIRLY STRONG COLD FRONT WILL CROSS NORTHERN
UTAH THURSDAY AFTERNOON THROUGH EARLY FRIDAY. DRY AND MILD SOUTHWEST
FLOW WILL RETURN FOR THE WEEKEND AND EARLY NEXT WEEK.

&&

.DISCUSSION...SOUTHWESTERLY FLOW ALOFT PREVAILS ACROSS THE GREAT
BASIN THIS EVENING...DOWNSTREAM FROM AN UPPER LOW SPINNING OVER
THE PACIFIC NORTHWEST. A VERY WARM AND DRY AIRMASS REMAINS IN
PLACE ACROSS ALL BUT THE FAR NORTHWEST CORNER OF UT...RESULTING IN
A VERY WELL PRONOUNCED INVERTED-V PROFILE IN THE 00Z KSLC
SOUNDING. MID LEVEL MOISTURE COMBINED WITH A JET STREAK MOVING
ACROSS THE AREA PROVED SUFFICIENT TO INDUCE VERY HIGH BASED
CONVECTION EARLY THIS EVENING...WHICH PRODUCED NUMEROUS DRY
MICROBURSTS ACROSS NORTHERN UT...THE STRONGEST OF WHICH PRODUCED A
75 MPH GUST IN WEST JORDAN. MUCH OF THIS ACTIVITY HAS
DIMINISHED...WITH SHOWER AND THUNDERSTORM ACTIVITY NOW
CONCENTRATED ACROSS FAR NORTHWEST UT ALONG LEADING EDGE OF 700MB
BAROCLINIC ZONE ASSOCIATED WITH PACIFIC NORTHWEST TROUGH.

THIS BAROCLINIC ZONE AND ASSOCIATED SURFACE FRONT WILL SLOWLY PUSH
EAST ACROSS NORTHERN UT THURSDAY ALLOWING FOR COOLER TEMPERATURES.
SOUTH OF THIS BOUNDARY A WARM AND DRY AIRMASS WITH BREEZY
SOUTHWEST WINDS WILL PREVAIL. PACIFIC NORTHWEST TROUGH WILL SWING
INLAND THURSDAY NIGHT USHERING A COOLER AIRMASS INTO THE REMAINDER
OF THE STATE...AND GIVING A BRIEF REPRIEVE TO PERSISTENT HOT...DRY
AND BREEZY CONDITIONS. THIS WILL BE SHORT LIVED HOWEVER...AS
SOUTHWESTERLY FLOW REDEVELOPS FOR THE UPCOMING WEEKEND INTO NEXT
WEEK.

&&

.AVIATION...SOUTHERLY SURFACE WINDS ARE EXPECTED TO SWITCH TO NORTH
AT ABOUT 07Z DUE TO OUTFLOW FROM CONVECTION OVER NORTHERN UTAH
EARLIER THIS EVENING. WILL HOLD ONTO THE IDEA THAT SOUTHERLY WINDS
WILL RETURN AROUND 12-13Z UNTIL ABOUT 18Z WHEN THE COLD FRONT
ARRIVES AND SHIFTS THE WINDS BEACK TO NORTHWEST. THERE IS A 30
PERCENT CHANCE THAT WINDS WILL REMAIN NORTHERLY THROUGH THE MORNING
AND THEN GET ENHANCED AT 18Z IF NOT EARLIER.

&&

.FIRE WEATHER...RED FLAG WARNING WILL CONTINUE ACROSS ZONES 496 AND
497 THROUGH LATE THURSDAY EVENING. ADDITIONALLY ZONES 495 AND 498
ALSO WERE DEEMED CRITICAL THIS AFTERNOON...AND WILL BE INCLUDED IN
THE RFW WITH THE MIDNIGHT ISSUANCE. LOW HUMIDITIES WITH POOR
OVERNIGHT RECOVERIES ARE EXPECTED. WINDS WILL GUSTY THROUGH LATE
THIS EVENING...THEN DECREASE BELOW CRITERIA LATE TONIGHT THROUGH
AT LEAST MID-MORNING THURSDAY. WINDS WILL LIKELY BE STRONGER FOR
LATE THURSDAY MORNING THROUGH THURSDAY EVENING AHEAD OF THE COLD
FRONT ENTERING NORTHWEST UTAH THURSDAY AFTERNOON.

ANY CONVECTION ASSOCIATED WITH THE FRONT WILL BE CONFINED TO THE FAR
NORTHWEST ZONES TONIGHT THROUGH ABOUT MID-AFTERNOON THURSDAY.
ORGANIZED SHOWERS/STORMS ARE NOT EXPECTED TO FOLLOWED THE FRONT
SOUTHEAST...THOUGH SUBSTANTIALLY COOLER TEMPERATURES WILL WORK INTO
CENTRAL AND NORTHERN UTAH FOR FRIDAY. BREEZY AND DRY CONDITIONS WILL
REMAIN AHEAD OF FRONT...AND MAY REQUIRE AN EXTENSION OF THE CURRENT
FIRE WEATHER HIGHLIGHTS BEYOND THURSDAY EVENING.

WARMER TEMPS WITH CONTINUED DRY CONDITIONS WILL COVER ALL DISTRICTS
THIS WEEKEND AS HIGH PRESSURE ALOFT MOVES INTO THE REGION. BREEZY
CONDITIONS COULD DEVELOP OVER THE WESTERN VALLEYS AS AN INCREASINGLY
STRONG SOUTHWEST DEVELOPS LATE IN THE WEEKEND.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...RED FLAG WARNING UNTIL 10 PM MDT THURSDAY FOR UTZ496-497.

WY...NONE.
&&

$$

PUBLIC...SEAMAN
FIRE WEATHER...CONGER
AVIATION...STRUTHWOLF

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)