****WEATHER WARNING****

[Rog Tallbloke]

There have been a couple of threads about upcoming trips this week. This in from the NOAA. Basically, the remnants of super typhoon Melor is on it's way in. The forecast talks about rain, but CA seem to be around 4C below average at the moment and there have been reports of early snow from around the states.

Stay safe and warm everyone.

http://www.srh.noaa.gov/data/MTR/AFDMTR

000
FXUS66 KMTR 091556
AFDMTR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA
900 AM PDT FRI OCT 9 2009

…SIGNIFICANT STORM SYSTEM TO IMPACT FORECAST AREA EARLY NEXT
WEEK…

.DISCUSSION…LARGE SCALE SYNOPTIC PATTERN SHOWS HIGH AMPLITUDE RIDGE TROUGH PATTERN WITH FULL LATITUDE RIDGE LOCATED ALONG 135W WITH COLD UPPER LOW DIGGING SOUTH THROUGH EASTERN MT AND NORTHERN HIGH PLAINS. VERY DEEP 967 MB LOW 45.6/156W MOVING NORTH INTO THE GULF OF ALASKA.

GIVEN HIGH PRESSURE ALOFT AND AT THE SURFACE OVER CA THIS AM HAVE WELL DEFINED MARINE LAYER NOW AT 2200 FT BASED ON SFO SODAR. EARLY VIS SATL IMAGERY SHOWS MARINE STRATUS HAVING PENETRATED WELL INLAND WITH SOLID STRATUS COVERING MOST OF THE EASTERN PACIFIC. WITH SUN ANGLE A LITTLE LOWER AND STRATUS ABOUT 800 FT THICK EXPECT SLOW BURN OFF WITH STRATUS LINGER MOST OF THE DAY AT THE COAST. HIGH TEMPERATURES MAY BE SLIGHTLY COOLER TODAY GIVEN EXTENT OF STRATUS. THIS IS NOT REFLECTED IN THE CURRENT FORECAST SO WILL REVIEW THIS FOR POSSIBLE UPDATE.

MODELS SHOWING DEVELOPMENT OF A WEAK UPPER LOW BY SAT MORNING JUST OFF THE CENTRAL CA COAST. THIS ENERGY IS CURRENTLY MOVING DOWN THE BACK SIDE OF THE HIGH AMPLITUDE RIDGE AND SHEARS OFF UNDERNEATH THE RIDGE AS IT BEGINS TO MOVE EAST. EXPECT THIS WILL CONTINUE TO DEEPEN THE MARINE LAYER BUT NOT ENOUGH TO MIX IT OUT FOR TOMORROW. SO EXPECT POSSIBLE EARLY RETURN OF THE LOW CLOUDS THIS EVENING AND WIDESPREAD LOW CLOUDS OVER THE AREA TOMORROW MORNING AND POSSIBLY WELL INTO THE DAY TOMORROW. THIS MAY COOL HIGH TEMPERATURES EVEN MORE FOR SAT SO WILL REVIEW THIS AS WELL.

BY SUN WE BEGIN TO SEE THE TRANSITION TO WHAT WELL BECOME A VERY STORMY PERIOD INTO THE MIDDLE OF NEXT WEEK. FIRST OF WHAT MAY BE THREE INDIVIDUAL UPPER TROUGHS UNDERCUTS THE HIGH AMPLITUDE RIDGE LATE SUN INTO MONDAY AT ABOUT 35N. WOULD EXPECT ENOUGH LIFTING OF THE MARINE LAYER TO BEGIN MIXING OUT THE LOW CLOUDS BY LATE SUNDAY BEFORE THE MIDDLE AND HIGH CLOUDS BEGIN TO MOVE IN FROM THIS FIRST TROUGH. TIMING OF THESE EVENTS IS GOING TO BE BASED ON THE 00Z EURO AND NOT THE 06Z GFS WHICH HAS DEVIATED FROM WHAT THE LAST SEVERAL DAYS OF MODEL RUNS HAVE BEEN SHOWING. WILL UPDATE THIS IN THE AFTERNOON DISCUSSION IF 12Z EURO AND GFS INDICATE OTHERWISE.

EXTENDED…
SO USING THE 00Z EURO AS THE BASIS FOR THIS SIGNIFICANT UPCOMING EVENT HERE IS THE SEQUENCE OF EVENTS CURRENTLY EXPECTED. THIS FIRST TROUGH MOVES IN UNDER THE RIDGE WITH RAIN BEGINNING ALONG THE COAST JUST BEFORE SUNSET ON MONDAY. APPEARS THIS FIRST WAVE WILL ROTATE NORTH INTO NORTHERN CA MONDAY NIGHT WITH MOST OF THE RAIN FROM ABOUT SANTA CRUZ NORTH. WINDS WILL BEGIN TO INCREASE ALONG THE COAST AND OVER THE COASTAL WATERS MONDAY NIGHT BUT NOT EXPECTED TO REACH CRITERIA FOR HIGH WINDS UNTIL THE DAYLIGHT HOURS TUESDAY. THE SECOND MAJOR TROUGH DROPS INTO THE MAIN UPPER TROUGH THAT SETS UP UNDER THE CUTOFF HIGH OVER SOUTHERN AK. THIS ENERGY IS ASSOCIATED WITH WHAT WAS WESTERN TYPHOON MELOR. THIS WILL BE THE MOST SIGNIFICANT PERIOD OF RAIN AND WIND AT APPEARS TO BE FOCUSED ALONG THE CENTRAL COAST FROM MARIN DOWN TO BIG SUR. HEAVY RAIN STRONG GUSTY WINDS SHOULD LAST THROUGH WED EVENING THEN SHOULD SEE WINDS AND RAIN DIMINISH AS THE FRONT PASSES SOUTH. EURO AND 00Z GFS INDICATING PWS APPROACH 2 IN OFFSHORE CENTRAL CA WITH WINDS AT THE 925 MB LEVEL OF 55 TO 60 KTS. THIS IS A VERY POTENT COMBINATION AND SHOULD PRODUCE COPIOUS AMOUNTS OF RAIN AT THE HIGHER ELEVATIONS WITHIN THE FORECAST AREA. FIVE TO EIGHT INCHES OF RAIN FOR THE PERIOD MONDAY NIGHT THROUGH WED MORNING ARE CERTAINLY POSSIBLE WITH LOCALIZED AMOUNTS OF CLOSE TO 10 IN. THE KEY WILL BE HOW LONG THIS ATMOSPHERIC RIVER OF VERY HIGH MOISTURE LINGERS OVER ANY GIVEN LOCATION. WITH SOME GOOD UPPER DYNAMICS ASSOCIATED WITH 155KT 200 MB JET SHOULD EXPECT LOWER ELEVATIONS OUTSIDE ANY SIGNIFICANT RAIN SHADOWING TO RECEIVE 1 TO 3 INCHES OF RAIN AND POSSIBLY MORE. TRYING TO DRAW ANALOGIES TO PREVIOUS EVENTS IS ALWAYS TRICKY. WE HAVE LOOKED AT RECENT EVENTS LIKE JAN 4-5 2008 AND DEC 12, 1995 AS CLOSE COUSINS TO WHAT MODELS ARE FORECASTING. THIS STORM HAS HIGHER MOISTURE SUPPLY BUT MAY NOT HAVE AS SIGNIFICANT A WIND COMPONENT. AGAIN WE ARE STILL SEVERAL DAYS OUT AND TRYING TO PINPOINT EXACT IMPACTS ARE DIFFICULT. WILL UPDATE THE SPS THIS AFTERNOON TO TRY AND HIGHLIGHT EXPECTED IMPACTS OF WHAT IS EXPECTED TO BE A VERY SIGNIFICANT EVENT…ESPECIALLY FOR THE FIRST STORM OF THE YEAR.

[Rog Tallbloke]

BUMP

[Michael Skwarczek]

Cheers, Rog

Just got back from a few days in the Eastern Sierras outside of Bridgeport. Beautiful days and nights, but this is all the talk on the way out. I am reconsidering my 7-day this coming weekend.

[Jim Carr]

And I was hoping to get into the Trinitys this weekend for one last trip. It also shows it might stop and be clear starting Friday.

[Michael Skwarczek]

My real concern is with what's left behind. I imagine North and East faces holding snow enough to make an ascent or descent through passes too dicey a risk.

And I'm really not sure about my feet. I have trail runners ,and then more serious winter footwear that I wouldn't consider for a shoulder season of possible snow. Wet feet gets tiring.

UPDATE:
http://forecast.weather.gov/showsigwx.php?warnzone=CAZ073&warncounty=CAC051&firewxzone=CAZ273&local_place1=14+Miles+SSE+Leavitt+Meadows+CA&product1=Special+Weather+Statement

"SIGNIFICANT STORM SYSTEM WILL IMPACT MUCH OF THE WESTERN U.S.
TUESDAY INTO WEDNESDAY. UP TO 6 INCHES OF RAIN IS EXPECTED FOR
THE SIERRA…INCLUDING 2 TO 3 INCHES IN THE TAHOE BASIN. SEVERAL
FEET OF SNOW ARE LIKELY AT THE HIGHEST ELEVATIONS AND BACKCOUNTRY
OF THE SIERRA…MAINLY ABOVE 9000 FEET. IN THE LOWER ELEVATIONS OF
WESTERN NEVADA AND NORTHEAST CALIFORNIA…UP TO AN INCH OF RAIN IS
POSSIBLE FROM THIS STORM.

SNOW LEVELS WILL START AROUND 7500 FEET THIS EVENING. HOWEVER
WARM AND MOIST PACIFIC AIR WILL PUSH SNOW LEVELS TO 9000 FEET OR
HIGHER BY TUESDAY AFTERNOON. THESE HIGH SNOW LEVELS WILL REDUCE
IMPACTS FROM SNOW ACCUMULATIONS. SNOW LEVELS WILL LOWER SOMEWHAT
EARLY WEDNESDAY AS PRECIPITATION BEGINS TO TAPER. LIGHT
ACCUMULATIONS OF SNOW COULD POSE A BRIEF PERIOD OF TRAVEL
INCONVENIENCE ON AREA PASSES MAINLY ABOVE 7500 FEET AT THE
BEGINNING OF THE EVENT EARLY TUESDAY AND AGAIN WEDNESDAY MORNING.

[W I S N E R !]

I know you were excited about your upcoming trip.
Sounds like this changes things some…

[Rick Dreher]

The good news is it should put a halt to the northern and central Californian fire seasons :-)

I imagine the Trinities will only get snow on the highest peaks and rain elsewhere. The storm is supposed to clear out by Thursday.

The highest central and southern Sierra passes are likely to get enough snow to last until next season. I'll wager the northern Sierra will see melt-off of a good deal of the accumulation before the more typical Arctic fronts hit as winter approaches (keeping fingers crossed for a lot of those this season).

Even without the possibility of snow, the wind forecast would be enough to keep me out of the high country the next three days.

Cheers,

Rick

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