afd

Current Version                Previous Version:  1  2  3  4  5  

AREA FORECAST DISCUSSION

 
 FXUS65 KSLC 012219
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
419 PM MDT WED APR 1 2015

.SYNOPSIS...A PACIFIC WEATHER DISTURBANCE WILL CROSS THE AREA LATE
TONIGHT AND THURSDAY. HIGH PRESSURE ALOFT WILL RETURN FOR FRIDAY.
A WARM SOUTHWEST FLOW WILL DEVELOP SATURDAY.

&&

.SHORT TERM (THRU 00Z SUNDAY)...STRONG LOW LEVEL COOLING IN THE
WAKE OF LAST NIGHTS COLD FRONT HAS KEPT THE AIRMASS TOO STABLE FOR
ANY CONVECTIVE DEVELOPMENT AND IT HAS BEEN A DRY COOL DAY SO FAR.

THE NEXT SHORT WAVE CURRENTLY MOVING THRU THE PACNW AND INTO THE
GREAT BASIN WILL SPREAD CLOUDS INTO THE CWA TONIGHT AS IT
CONTINUES TO TRACK EAST.

THE BACKING FLOW TIGHTENS THE THERMAL GRADIENT GENERATING LIFT
ACROSS THE CENTRAL AND NRN CWA. LIGHT PRECIP WILL DEVELOP IN THIS
AREA STARTING LATE TONIGHT THEN ENDING BY TOMORROW AFTN AS THE
WAVE SHIFTS EAST. THE PRECIP WILL LIKELY END UP IN A FAIRLY
NARROW BAND THAT STARTS SOMEWHERE NEAR A SALT LAKE TO DUGWAY LINE
BEFORE SUNRISE THAT THEN SHIFTS SOUTH THRU THE MORNING THEN OFF
TO THE EAST IN THE AFTERNOON. EXPECT ISOLATED TO SCATTERED SNOW
SHOWERS THU AFTN ACROSS NRN AND CENTRAL UT AS THE COLD POOL ALOFT
COMES OVERHEAD THAT END QUICKLY BY SUNSET.

PRECIP SHOULD FALL AS SNOW DOWN TO THE VALLEY FLOORS BUT NOT
ACCUMULATE. SEVERAL INCHES ARE POSSIBLE IN THE MTNS HOWEVER BUT
EVEN HERE DO NOT EXPECT ANY TRAVEL IMPACTS OTHER THAN VISIBILITY
ISSUES. DO EXPECT SOME FALLING SNOW OVER PARLEYS SUMMIT FOR THE
MORNING COMMUTE.

THE THREAT OF FREEZING TEMPS LOOK TO BEGIN AS EARLY AS TONIGHT
NORTH OF ABOUT SLC ALTHO THIS MAY BE TEMPERED BY CLOUD COVER.
STILL EXPECT ENOUGH AREAS TO DIP INTO THE UPPER 20S TO WARRANT
ISSUING A FREEZE WARNING FOR THIS AREA TONIGHT. CLEARING SKIES
AND A COLDER AIRMASS SHOULD MAKE FREEZING TEMPS MORE WIDESPREAD
THU NIGHT AND HAVE EXTENDED THE WARNING THRU 9AM FRI. ALSO
INCLUDED THE REMAINDER OF THE AREA CURRENTLY DEEMED CRITICAL IN A
WATCH FOR THU NIGHT.

RIDGE CONDITIONS MOVE OVER THE CWA ON FRI AND THE AIRMASS WARMS
AS A LIGHT SOUTHWEST FLOW DEVELOPS IN THE AFTERNOON. THIS FLOW
BECOMES STRONGER SAT INTO SUN AS THE NEXT COLD FRONT APPROACHES
AND TEMPS SAT SHOULD RETURN TO ABOVE NORMAL READINGS.

&&

.LONG TERM (AFTER 00Z SUNDAY)...WINDS ARE EXPECTED TO PICK UP QUITE
A BIT ON SUNDAY AHEAD OF THE NEXT APPROACHING STORM SYSTEM WITH
EC/GFS INDICATING 700 MB FLOW TO ABOUT 40 KTS OVER SOUTHERN UTAH.
ALL MODELS PUSH THE SYSTEM THROUGH SUNDAY AFTERNOON...BUT THIS WAVE
IS NOTICEABLY WEAKER IN THE 12Z EC COMPARED TO THE GFS. THE GFS
PUSHES A WELL DEFINED FRONT THROUGH LATE SUNDAY AFTERNOON THROUGH
MONDAY...WITH 700 MB TEMPS DROPPING AS LOW AS -11C OVER NORTHERN
UTAH COMPARED TO AROUND +1C OUT AHEAD OF IT. EC HAS A MUCH WEAKER
FRONT THAT BRINGS MORE GRADUAL COOLING AND CONFINES IT PRIMARILY TO
NORTHERN AND CENTRAL UTAH. STILL...700 MB TEMPS DROP DOWN TO ABOUT -
7C IN THAT SOLUTION. NEITHER SOLUTION INDICATES AN IMPRESSIVE AMOUNT
OF MOISTURE...BUT THE GFS SOLUTION WOULD BRING A BIT MORE PRECIP
THAN THE EC SOLUTION. SLIGHT CHANCE/CHANCE POPS IN THE FORECAST
PACKAGE SEEM TO COVER THE THREAT WELL AND DID NOT MAKE A LOT OF
CHANGES THERE.

GFS BRINGS RIDGING OVER THE AREA EARLY TUESDAY BETWEEN THE EXITING
SYSTEM AND ANOTHER APPROACHING PACIFIC STORM SYSTEM WHILE THE EC
SHOWS LITTLE BREAK BETWEEN THE TWO FEATURES. NEITHER SOLUTION SHOWS
MUCH COOLING AS THE SYSTEM MOVES THROUGH TUESDAY NIGHT AND WEDNESDAY
BUT WITH MORE MOISTURE IT HAS THE POTENTIAL TO BE A BIT OF A BETTER
PRECIP PRODUCER. LATEST EC IS FASTER MOVING THE SYSTEM
OUT...INDICATING HIGH PRESSURE MOVING BACK IN NEXT THURSDAY WHILE
THE STORM LINGERS OVER UTAH AND SOUTHWEST WYOMING IN THE GFS. WITH
BOTH MODELS INDICATING AN UNSETTLED PATTERN...HAVE KEPT POPS NEAR
CLIMO FOR DAY 7.

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE
EVENING WITH INCREASING CLOUDS. CIGS ARE EXPECTED TO STAY ABOVE 6000
FT AGL. WEST TO NORTHWEST WINDS WILL CONTINUE THROUGH THE EVENING.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...HARD FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
MORNING FOR UTZ003-004-013.

HARD FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM MDT FRIDAY FOR
UTZ001-002-005.

WY...NONE.
&&




SHORT TERM...WILENSKY
LONG TERM/AVIATION...TRAPHAGAN

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)