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……………………….:-)

Quiet weather week ahead

DWEEBS OFF ON VACATION THE NEXT WEEK AND THE WEATHER SHOULD BE PRETTY QUIET ACCORDING TO THE LATEST GUIDANCE….

HOWEVER WITH THAT SAID, THE DWEEBS CAN NOT IGNORE THE GIANT MJO DEVELOPING OVER THE MARITIME CONTINENT, ALREADY RESPONSIBLE FOR THE FLOODING THROUGHOUT INDONESIA.

THE ISSUE ABOUT THESE MJO’S IS THAT THEIR SIGNAL IS OFTEN TIMES EVIDENT WELL BEFORE THEY GET INTO THE GLOBAL MODELS. STAY TUNED AS THE DWEEBS WILL BE MONITORING THIS AND MAY HAVE TO UPDATE THE FORECAST DURING VACATION NEXT WEEK.

OTHERWISE AND BASED UPON CURRENT GUIDANCE….

MODERATE RIDGING IS EXPECTED OVER THE WEST WITH A WEAK DISTURBANCE HERE AND THERE. THUS A SLIGHT CHANCE OF A FEW SHOWERS MONDAY AND TUESDAY, TEMPS WILL STILL BE SOMEWHAT SEASONAL TO SLIGHTLY ABOVE.

HIGHS FOR MAMMOTH WILL RANGE IN THE 60S NEXT WEEK WITH LOWS MOSTLY IN THE 30S.

ADIOS…………….:-)

Blue bird on Friday

BLOCKING PATTERN OVER THE CONUS IS BEGINNING TO PROGRESS EAST AS A SHORT WAVE OVER CENTRAL CANADA PICKS UP THE CUTOFF LOW, NOW OVER PA…..THEN LIFTS IT THROUGH NEW ENGLAND. THIS WILL ALLOW THE WAVE LENGTH, UP-STREAM TO OPEN UP AND ALLOW THE CENTRAL CA CUT OFF TO LIFT THROUGH THE SOUTH CENTRAL SIERRA EARLY THURSDAY AM. EXPECT A DAY TODAY SOMEWHAT SIMILAR TO YESTERDAY WITH SHOWERS AND THUNDER, WITH A SNOW LEVEL ABOUT 8K. ONCE THE UPPER LOW STARTS TO MOVE THIS AFTERNOON….UVM WILL INCREASE ALONG WITH PRECIPITATION IN THE SIERRA TONIGHT.
SNOWFALL WILL OCCUR IN TOWN LATER TODAY AND PICK UP TONIGHT WITH A FEW INCHES POSSIBLE. THE COLD POOL MOVES INTO AND THROUGH THE SIERRA THURSDAY AM. I WOULD NOT BE SURPRISED IF THE VILLAGE AT MAMMOTH PICKED UP 2 TO 3+ INCHES OF SNOW BY MID THURSDAY AM.

RIDGING MOVES INTO CALIFORNIA THURSDAY NIGHT AND INTO FRIDAY. A BLUE BIRD MORNING IS EXPECTED FRIDAY…THAT IS FOR THE BLUE BIRDS THAT ARE STILL IN TOWN. WARMER WEATHER IS EXPECTED FRIDAY THROUGH SUNDAY WITH HIGHS IN THE MID 60S BY SUNDAY.

PROGRESSIVE PATTERN CONTINUES INTO EARLY NEXT WEEK WITH A STRONG SHORT WAVE MOVING INTO THE PACIFIC NORTHWEST. AT THE MOMENT….THIS SYSTEM IS TRACKING WELL TO THE NORTH OF MAMMOTH. ACCORDING TO THE ECMWF ENSEMBLES THIS AM….500HT HEIGHT FALLS OF OVER 100DM ARE EXPECTED BY MONDAY PM, SO WE’LL GET SOME WIND AND ABOUT 5 TO 10 DEGREES OF COOLING BY TUESDAY. A SURFACE HIGH IN THE SYSTEMS WAKE TUESDAY AM WILL CHURN UP A NE GRADIENT OVER THE EASTERN SLOPES AND SIERRA CREST, SO ALTHOUGH 500 MB HEIGHTS RISE BACK ABOVE 582DM BY WEDNESDAY…THE WARMING MAY NOT BE SO QUICK THROUGH MID WEEK FOR MAMMOTH. HOWEVER…IT WILL CERTAINLY BE WARMER AT THE COAST! OVERALL…NEXT WEEK LOOKS DRY WITH SOMEWHAT ABOVE NORMAL TEMPS. CLIMO NOW FOR MAMMOTH IS 63 AND 31.

WESTERN HEMI:
THE MAIN KEY ANCHORING UPPER HEIGHT ANOMALY IS SOMEWHAT WEST OF THE DATELINE NEAR THE POSITIVE SSTA POOL, WITH THE LONG WAVE TROF NORTH OF HAWAII AND THE DOWNSTREAM UPPER HIGH ABOUT THE GREAT BASIN.

INDIAN SUMMER BEGINS THIS WEEKEND!