FXUS65 KSLC 050445
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
945 PM MST FRI DEC 4 2009
.SYNOPSIS...A COLD TROUGH WILL MOVE SOUTH INTO THE AREA SATURDAY
AND REMAIN INTO SUNDAY. ANOTHER COLD TROUGH WILL CROSS THE GREAT
BASIN SUNDAY NIGHT THROUGH TUESDAY. THIS UNSETTLED PATTERN WILL
CONTINUE THROUGH MUCH OF NEXT WEEK.
&&
.DISCUSSION...A STORM SYSTEM IS CURRENTLY SEEN ON WATER VAPOR
IMAGERY DIVING SOUTH FROM THE PACIFIC NORTHWEST STATES AND IDAHO AND
MONTANA. THIS STORM IS EXPECTED TO PUSH A COLD FRONT ACROSS NORTHERN
UTAH TOMORROW MORNING...THEN INTO SOUTHERN UTAH DURING THE AFTERNOON.
AHEAD OF THE STORM...A DRY AIRMASS REMAINS IN PLACE OVER UTAH THIS
EVENING. WARM ADVECTION THIS AFTERNOON HAS RAISED 700MB TEMPERATURES
OVER SLC TO -5C AT 00Z. HOWEVER...THIS HAS ONLY SERVED TO TRAP COLD
AIR IN THE VALLEYS WHERE WARMING WAS RATHER LIMITED TODAY. SURFACE
WINDS ARE NOT EXPECTED TO BE STRONG TONIGHT AHEAD OF THE FRONT...SO
GIVEN THE LIGHT WINDS...VERY LOW DEWPOINTS IN PLACE AND GENERALLY
CLEAR SKIES...EXPECT EXCELLENT RADIATIVE COOLING. THIS WILL AGAIN
YIELD COLD OVERNIGHT MINS FOR MUCH OF THE AREA. A FEW PLACES ARE
ALREADY COLDER THAN FORECAST...SO WILL UPDATE TO LOWER MIN
TEMPERATURES FOR TONIGHT.
THE STORM SYSTEM TOMORROW IS EXPECTED TO BRING SOME SNOW TO PORTIONS
OF THE CWA. HOWEVER...GIVEN THE CONTINENTAL ORIGINS OF THE
AIRMASS...SNOW AMOUNTS ARE NOT EXPECTED TO BE VERY SIGNIFICANT. SNOW
LOOKS TO LAG THE SURFACE FRONT BY A FEW HOURS AND WILL LIKELY FOCUS
ALONG CENTRAL/SOUTHWEST UTAH AND THE UINTA MOUNTAINS WHERE 700MB
CONVERGENCE WILL BE STRONGEST. SNOW LOOKS TO TAPER OFF OVER MOST
AREAS BY SUNDAY MORNING. WILD CARD WITH THIS EVENT WILL BE THE GREAT
SALT LAKE. COLD AIRMASS OF AROUND -18C AT 700MB SHOULD KEEP STEEP
LAPSE RATES OVER THE GSL...QUESTION IS WHETHER MOISTURE AND WIND
FIELDS WILL BE FAVORABLE FOR THE DEVELOPMENT OF LAKE-EFFECT BANDS.
ANOTHER STORM SYSTEM IS STILL ON TRACK TO IMPACT THE AREA SUNDAY
NIGHT THROUGH TUESDAY. MOISTURE WILL BE TAPPED FROM A WEAKENING
STORM SYSTEM OVER THE PACIFIC...AND COUPLED WITH THE STRENGTHENING
STORM SYSTEM...SIGNIFICANT SNOW CAN BE EXPECTED ESPECIALLY ACROSS
SOUTHERN AND CENTRAL UTAH. WINTER WEATHER HEADLINES LOOK LIKE A GOOD
BET FROM FUTURE SHIFTS...BUT FOR NOW A SPECIAL WEATHER STATEMENT IS
IN PLACE TO HIGHLIGHT THE POTENTIAL FOR SIGNIFICANT WEATHER.
&&
.AVIATION...SOUTHERLY WINDS AND VFR CONDITIONS WILL PREVAIL AT THE
SLC TERMINAL THROUGH TONIGHT. A COLD FRONT WILL PASS THROUGH THE
TERMINAL SATURDAY MORNING...WITH A WIND SWITCH TO NORTHWEST EXPECTED
BETWEEN 14Z AND 16Z. CEILINGS WILL DROP BELOW 6000FT AGL AFTER
17Z...WITH A 30 PERCENT CHANCE OF MVFR OR HIGH-END IFR CONDITIONS IN
SNOW SHOWERS DURING THE AFTERNOON HOURS.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...CHENG
AVIATION...SCHOENING
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
