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storm’s coming…
By ccrossen | October 8, 2009
Looks like we’re going to get out first real storm of the season, with some impressive rain/snow mix. QPF is anywhere from 1/2 - 2+ inch range for Tahoe, depending on where the bulk of the system hits. So, a ton of rain or a lot of snow. At this point, models forecast a relatively warm system, with snow levels rather high, 7,000+. We may have a drop in snow levels at some point, midway through. The fun begins Monday as a low approaches the Northern California Coast and starts throwing moisture our way. Currently, models diverge, and, again, it’s not exactly clear where the bulk of the system will pinpoint - North of us, South of us, or a direct hit. This system should last into Tuesday night/Wednesday morning. We’ll see what happens. Nice to see some systems coming through this early-on.
545 AM PDT THU OCT 8 2009
…WET AND COOLER WEATHER EXPECTED MONDAY THROUGH WEDNESDAY…
THE WEATHER PATTERN IS EXPECTED TO CHANGE MONDAY AS A LOW PRESSURE SYSTEM FROM THE GULF OF ALASKA APPROACHES THE WEST COAST. THIS SYSTEM IS EXPECTED TO BRING COOLER TEMPERATURES AND
SIGNIFICANT PRECIPITATION ALONG WITH GUSTY WINDS THROUGH MIDDLE OF NEXT WEEK. PRECIPITATION IS EXPECTED TO BEGIN MONDAY AFTERNOON ALONG THE COASTAL RANGE AND SPREAD ACROSS INTERIOR NORTHERN CALIFORNIA BY TUESDAY MORNING. PRECIPITATION IS LIKELY ON TUESDAY AND WILL LINGER INTO AT LEAST WEDNESDAY. STRONG DYNAMICS ALONG WITH DECENT MOISTURE WITH THIS SYSTEM COULD BRING SIGNIFICANT PRECIPITATION TO NORTHERN CALIFORNIA. SNOW LEVELS ARE EXPECTED TO BE AROUND 7000 TO 8000 FEET TUESDAY AND THEN DROP TO AROUND 6000 TO 7000 FEET ON WEDNESDAY.
NATIONAL WEATHER SERVICE RENONV
321 AM PDT THU OCT 8 2009
LONG TERM…SUNDAY THROUGH WEDNESDAY…
MINIMAL CHANGES MADE TO EARLY PORTIONS OF THE EXTENDED FORECAST THIS CYCLE WITH MORE SUBSTANTIAL CHANGES MADE TO THE LATTER PORTIONS. EARLY ON…RIDGE SITUATED ALONG THE CA COAST BEGINS TO MOVE EAST WITH MILD TEMPS FOR SUNDAY. BY EARLY MONDAY TROUGH BEGINS TO APPROACH THE COAST AND MEDIUM RANGE DETERMINISTIC MODELS AND MOST GEFS ENSEMBLE MEMBERS AREA IN GOOD AGREEMENT WITH INCREASING MID/UPPER LVL MSTR THROUGH THE DAY MONDAY.
SPEAKING OF THE ECMWF…IT APPEARS TO HAVE BECOME AN OUTLIER FOR THE MONDAY/TUESDAY TIME FRAME THIS FORECAST CYCLE. IT IS NOW PRODUCING QPF FARTHER INLAND LATE MONDAY AND MUCH HIGHER AMOUNTS BY EARLY TUESDAY THAN THE OPERATIONAL GFS. THE GEFS ENSEMBLE MEMBERS ARE TENDING TO THROW MOST OF THEIR SUPPORT BEHIND THE TIMING OF THE OPERATIONAL GFS…WHICH HAS NOT BEEN THE CASE RECENTLY.BY LATE TUESDAY THE ECMWF IS PUSHING THE VAST MAJORITY OF ITS QPF SOUTH INTO THE CENTRAL SIERRA WHILE THE GFS SPREADS ITS QPF A BIT MORE UNIFORMLY FROM THE CENTRAL SIERRA NORTH INTO THE SRN CASCADES. BOTH STILL MAINTAIN THE PRIMARY UPPER LOW OVER THE GULF OF AK THROUGH THIS TIME BUT HAVE A GOOD TAP OF DEEP ERN PAC MSTR WITH MID LVL FLOW FROM WSW INTO THE CA COAST. TEMPS REMAIN RATHER MILD IN THE MID/UPPER LVLS AS WELL THROUGH TUESDAY. SNOW LEVELS STILL APPEAR TO BE IN THE 8500-9500 FT RANGE. ALTHOUGH BOTH THE GFS AND THE ECMWF DO INDICATE A BRIEF PERIOD OF TIME EARLY IN THE EVENT…SAY LATE MONDAY NIGHT INTO EARLY TUESDAY…WITH SNOW LEVELS DROPPING ACROSS THE NRN CWA. THIS IS OVERCOME BY WARM AIR ADVECTION IN THE MID LVLS BY TUESDAY.
EVEN THROWING THE OVER DONE QPF FROM THE ECMWF OUT…AMOUNTS STILL LOOK IMPRESSIVE FOR MID OCTOBER WITH THE GFS GENERATING 1-2 INCHES ALONG THE CREST BY LATE TUESDAY. AMOUNTS EAST OF THE CREST DROP OFF RATHER QUICKLY BUT ARE STILL IN THE 1/2-1 INCH RANGE OVER PORTIONS OF NE CA AND THE TAHOE BASIN.
MOIST WSW FLOW CONTINUES INTO THE OVERNIGHT HOURS TUESDAY NIGHT AS TROUGH REMAINS JUST ALONG THE COAST OR MOVES SLIGHTLY INLAND. SOME ENSEMBLE MEMBERS BY THIS TIME ARE STARTING TO FLATTEN THE TROUGH A BIT MORE THAN THE OPERATIONAL GFS. ECMWF IS ALSO TRENDING TOWARD A FLATTER MORE PROGRESSIVE PATTERN BY LATE TUESDAY NIGHT. QPF AMOUNTS ARE AGAIN IMPRESSIVE TUESDAY NIGHT BUT WITH HIGHEST AMOUNTS ALONG AND WEST OF THE CREST…AS ONE WOULD EXPECT. SNOW LEVELS REMAIN RATHER HIGH AS WELL TUESDAY NIGHT. HAVE OPTED TO INCREASE POPS ALONG THE CREST FROM BOTH TUESDAY AND TUESDAY NIGHT WITH SOME LIKELY POPS NOW ACROSS THE FAR WESTERN CWA IN THE HIGHER ELEVATIONS AROUND TAHOE AND INTO PLUMAS AND WESTERN LASSEN COUNTIES.
Topics: Tahoe Snow Report |