THIS MORNINGS ANALYSIS AT 500MB SHOWED SOUTHERLY FLOW FROM WEST OF THE TIP OF BAJA INTO CALIFORNIA THEN BACKING FROM THE SOUTHEAST AS IT REACHED INTO THE MOJAVE DESERT….THEN OFF SHORE PULLING AROUND THE SAN DIEGO “WARM-CORE” UPPER CUT-OFF. THIS SUBTROPICAL FEATURE CONTINUES TO PUMP UP QUITE A BIT OF MOISTURE WITH PWAT IN THE COLUMN AS MUCH AS 1.6 OVER SOUTHERN CA. IT APPEARS THAT THE AREA BETWEEN TO THE NORTH OF SANTA BARBARA AND TO THE EXTREME SOUTHWEST PORTION OF THE SAN JOAQUIN VALLEY EAST TO THE ANTELOPE VALLEY WILL BE THE FOCUS OF VERY ACTIVE WEATHER TODAY. THIS AREA IS IN THE DIVERGENT NORTHEAST QUAD OF THE UPPER LOW. THE LI INDEX IS FORECASTED CLOSE TO -5 WITH ENERGY AT 1500 J/KG. 😉

NO REAL CHANGES TO THE FORECAST TODAY IN THE MAMMOTH HIGH COUNTRY WITH SCATTERED SHOWERS AND THUNDER POSSIBLE THIS AFTERNOON AND EVENING. THE COOLING TREND CONTINUES WITH MORE RAPID COOLING EXPECTED SUNDAY INTO TUESDAY WITH THE NEW FORMING “COLD-CORE” CUT-OFF MONDAY PM. THE BIG MESSAGE HERE IS THAT WHETHER OR NOT WE GET ANY SIGNIFICANT PRECIP FROM THE PRESENT INFLUX OF MONSOON MOISTURE, IS NOT AS IMPORTANT AS THE REALIZATION, THAT THE SYSTEM WEST OF SAN DIEGO IS REALLY “PRIMING THE PUMP” MOISTURE WISE FOR THE UPCOMING COLD CORE CUT OFF EARLY NEXT WEEK. THE SLOW MOVING COLD-CORE CUTOFF LOW DIGGING OVER CALIFORNIA AND NEVADA WILL BE ABLE TO TAP MOISTURE FROM OLD MEXICO
AND GENERATE A FAIRLY SIGNIFICANT PRECIPITATION EVENT FOR MUCH OF THE GREAT
BASIN, ESPECIALLY SOUTHWEST PORTIONS, THEN WEST TO EASTERN PARTS OF THE SOUTHERN AND CENTRAL SIERRA AND WHITE MTS.

BY WEDNESDAY, AN ALMOST DUE SOUTHERLY FLOW ALOFT WILL KEEP MEXICAN MOISTURE FLOWING NORTHWARD INTO THE DESERT SOUTHWEST. SHOWERS ASSOCIATED WITH THIS UPPER FEATURE SHOULD CONTINUE UNTIL THE UPPER LOW FINALLY EJECTS OUT IN ABOUT A WEEK. AGAIN, THERE IS CHANCE OF SNOW SHOWERS OVER THE HIGHER ELEVATIONS OF THE SIERRA NEAR THE COLD-CORE OF THE UPPER LOW WHERE 500MB TEMPS MAY FALL TO AS LOW AS -20C. THE ECMWF FROM ITS 00Z SATURDAY RUN HAD THE COLD CORE OVER SEQUOIA NP TUESDAY PM, AND THEN JUST OFF SHORE WEST OF PASO ROBLES WEDNESDAY PM THEN ABOUT MAMMOTH THURSDAY PM. THE SAME OPERATIONAL RUN FOR THE GFS HAD THE UPPER LOW ABOUT DEATH VALLEY TUESDAY PM, THEN OVER THE MOJAVE DESERT WEDNESDAY PM. BY THURSDAY PM IT HAS WOBBLED BACK ABOUT OVER BEATTY, NV AGAIN. SO THE ACTUAL POSITION AND TIMING OF THE UPPER COLD CORE CUT-OFF WILL DETERMINE WHEN AND WHETHER THE MAMMOTH HIGH COUNTRY GETS MUCH SNOW OR NOT. 700MB TEMPS WITHIN THE CORE ARE AS COLD AS -2C WITH A LARGE AREA OF BETWEEN 0C AND -1C. STAY TUNED….IT GOING TO GET INTERESTING! 🙂

DR HOWARD AND “THE DWEEBS”……………………..:-)