The cake is still in the oven

FEW SHOWERS HERE OR THERE TODAY….NOT MUCH GOING ON UNTIL SATURDAY NIGHT OR SUNDAY……WET SUBTROPICAL MOISTURE PLUME HEADED INTO THE CENTRAL AND NORTHERN SIERRA AS EARLY AS SATURDAY NIGHT OR SUNDAY…….MOISTURE IS FROM TYPHOON MEGI (SEE EARLIER DISCUSSION)….GFS IS DRYER….SO JURY NOT COMPLETELY IN YET…. ECMWF PAINTS 1 TO 3 INCHES OVER YOSEMITE BY MONDAY….WITH SNOW LEVELS QUITE HIGH. COOLER AIR FOLLOWING SO A GOOD FROST LIKELY EARLY NEXT WEEK.

CPC….STRONGEST LA NINA SINCE 1949

THE STRONGER THE LA NINA THE GREATER THE ODDS FOR DRYER THEN NORMAL CONDITIONS FOR SOUTHERN CALIFORNIA……MAIN THRUST OF MOISTURE/SUBTROPICAL FEEDS WILL BE INTO THE PACIFIC NORTH WEST THIS WINTER. THE DWEEBS ALSO “VERY CONCERNED” ABOUT THE PROSPECTS FOR DRIER THEN NORMAL WEATHER FOR THE SOUTHERN 2/3S OF CALIFORNIA INCLUDING THE CENTRAL/SOUTHERN SIERRA. STILL AT THIS POINT…..THE CAKE IS STILL IN THE OVEN BAKING……..WILL SEE HOW EVERYTHING IS SHAPED UP BY THE MIDDLE OF NOVEMBER.

System will be unimpressive in Mammoth

ONLY CHANGE IN PATTERN IS TO PUSH WET JET INTO NORTHWEST LATER SATURDAY.
THERE COULD BE STRONG DOWN SLOPE WINDS FOR MAMMOTH SUNDAY….SYSTEM FOR MAMMOTH PRECIP WISE IS NOT IMPRESSIVE WITH ONLY SHOWERS POSSIBLE IF THAT. LOOKS LIKE WHISTLER, CANADA….COULD GET SEASON GOING WITH SUNDAY/MONDAY STORM…..MODERATE SANTANA POSSIBLE MIDDLE OF NEXT WEEK FOR LA.

Mid October overview

CURRENT:

EXPECT AN EASTERLY FLOW ALOFT TODAY AND TOMORROW ALONG WITH A CUT-OFF LOW OFF THE COAST OF NORTHERN BAJA THAT WILL KEEP THE CLOUDS AROUND THE NEXT FEW DAYS…POSSIBLY SOME LIGHT SHOWERS HERE OR THERE BUT NO BIG DEAL….ANOTHER SMALL BUT OPEN TROF WILL PROVIDE SOME EXTRA LIFT LATER THURSDAY INTO FRIDAY FOR A BETTER CHANCE OF SHOWERS AS THE UPPER FLOW BACKS AGAIN TO THE WSW.

MOISTURE…FROM TYPHOON MEGI NOW RECURRING TO THE NORTH TOWARD HONG KONG WILL BEGIN TO ENTER THE WESTERLY’S AT ABOUT 140E/160E AND SOUTH OF 40 NORTH ABOUT WEDNESDAY NIGHT/THURSDAY MORNING 12Z TIME. BY 00Z SATURDAY, SURFACE CYCLO-GENESIS REALLY GETS GOING AT 160WEST OR NORTH OF KAUAI AS A 180KNOT UPPER JET TAKES SHAPE WITH THE NOSE INTO THE OR/WA BORDER SATURDAY. IT LOOKS QUITE WET FOR THE PACIFIC NORTHWEST AND NORTHERN CA THIS WEEKEND WITH A LOT OF WIND SATURDAY FOR THE NORTHWEST AS A SURFACE CYCLONE OF 982MB SPINS UP OFFSHORE AND MAKES ITS WAY INTO VANCOUVER, CANADA BY SATURDAY NIGHT.

MAMMOTH WEATHER:

UPPER HIGH TO THE NORTH OF MAMMOTH AND A CUTOFF LOW TO THE SOUTH MEANS EASTERLY FLOW ALOFT OVER THE CENTRAL SIERRA TODAY. NO DYNAMICS TODAY OF SIGNIFICANCE SO DO NOT EXPECT MORE THEN A FEW LIGHT SHOWERS.

CURRENT CUT-OFF WSW OF ENSENADA WILL FOCUS MOST PRECIP ALONG THE COASTAL MTS FROM LA COUNTY SOUTH TO AND ESPECIALLY THE COASTAL PLANE OF SAN DIEGO COUNTY TODAY. SOME LIGHT PRECIP IS EXPECTED FOR THE CENTRAL OWENS VALLEY SOUTH AS WELL. A FEW SHOWERS FOR MAMMOTH IS POSSIBLE TODAY AND NOT MUCH CHANGE IS EXPECTED WEDNESDAY.

BY WEDNESDAY A KICKER TROF WILL NUDGE THE CUTOFF EAST TOWARD AZ. A BETTER CHANCE OF SHOWERS WILL SPREAD NORTH THURSDAY. THEN…THE UPPER FLOW BACKS TO THE SW AGAIN BY FRIDAY WITH BETTER UVM…SO SHOWERS ARE A BETTER BET THURSDAY/FRIDAY.

WEEKEND:

WET JET ASSOCIATED WITH MEGI MOISTURE SLAMS THE PACIFIC NORTHWEST AND NORTHERN CA LATER FRIDAY INTO SATURDAY. SEVERAL INCHES OF RAIN UP THERE POSSIBLE.. MAMMOTH WILL GET BREEZY BUT SHOULD REMAIN SOUTH OF THE UPPER JET UNTIL THE END OF THE WEEK WHEN THE 00Z TUESDAY ECMWF SAGS THE JET INTO NORTH CENTRAL CA BY MONDAY. OF NOTE…THE OPERATIONAL EC FROM LAST NIGHT IS ABOUT 60 METERS LOWER WITH ITS HEIGHTS THEN THE ENSEMBLES…SO THIS WILL BEAR WATCHING FOR MONDAY AS THE MAGIC 564 ISOHYET SAGS TO NEAR MAMMOTH BY 00Z TUE. ADDITIONALLY…THIS SYSTEM’S MOISTURE IS COMING INTO THE WEST COAST FROM THE WP LOWER LATT’S….AND SO LIGHT PRECIP IS POSSIBLE ALONG THE CENTRAL SIERRA CREST SATURDAY/SUNDAY EVEN THOUGH HEIGHTS WILL BE PRETTY HIGH.

PACIFIC SET UP.

OF NOTE:

IN EARLY SEPTEMBER…THE WARM WATER POOL THAT WAS NORTH OF BIG ISLAND OF HAWAII ALL SUMMER SHIFTED WEST TO 170W ABOUT THE 21ST OF SEPTEMBER, PROBABLY ADDING SUPPORT TO THE HEAT WAVE IN LA. FURTHER RETROGRESSION OF THE POOL NOW LOCATES IT ABOUT 165E WITH THE LONG WAVE HIGH FOLLOWING SUITE. THE DOWN STREAM LONG WAVE TROF HAS BEEN NORTH AND NEAR HAWAII FOR A WHILE NOW AND SST’S HAVE BEEN STEADILY COOLING. THE UPSHOT OF THIS ALL IS THAT THE DOWN STREAM UPPER RIDGE IS LOCATED NEAR THE NORTHWEST CONUS.

SO FAR THIS FALL…..THE HUDSON BAY LOW HAS BEEN AS IT SHOULD BE IN OCTOBER, PRETTY WEAK AND PROGRESSIVE. THIS HAS HAD THE EFFECT OF ALLOWING ENOUGH SPLIT FLOW IN THE UPSTREAM PATTERN TO ALLOW SHORT WAVES TO BECOME CUT OFF AND SETTLE IN OVER, OR JUST OFF THE CA COAST PROVIDING PRECIP FOR CA….ESPECIALLY THE SOUTHERN HALF.

THE DWEEBS CONCERN AT THIS POINT IS WHAT WILL HAPPEN TO THE PATTERN ONCE COLD AIR BEGINS TO PILE UP OVER EAST CENTRAL CANADA IN THE HUDSON BAY AREA. THE CURRENT WAVE LENGTH WOULD SUGGEST A FULL LATITUDE LONG WAVE RIDGE OVER THE FAR WEST DEVELOPING IN NOVEMBER IF THE CURRENT AIR/SEA COUPLING PERSISTS.

ADDITIONALLY THE QBO HAS BEEN TRENDING INCREASINGLY POSITIVE BETWEEN AUGUST TO SEPTEMBER (30 mb zonal wind index cda) WAS 6.57, MEANING STRATO WINDS ARE STARTING TO INCREASE FROM WEST TO EAST. FURTHER STRENGTHENING IS EXPECTED AS PER THE CYCLE. A WEST TO EAST DIRECTION WOULD SUGGEST A STRENGTHENING HUDSON BAY LOW AS WE GO TOWARD DECEMBER.

THE DWEEBER……………………….:-)