A second round of winter weather followed close on the heels of the previous episode and brought an additional amount of snow to the Sierra Nevada Mountains. The snow fell at a lower elevation with this storm than with the first episode.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS STO wrote it up.
A second round of winter weather followed close on the heels of the previous episode and brought an additional amount of snow to the Sierra Nevada Mountains. The snow fell at a lower elevation with this storm than with the first episode.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at May 27, 8:10 AM PST, 2 hours 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 910 AM PDT THU MAY 27 2010 .DISCUSSION... VORT LOBE LOCATED JUST OFF THE SFO COAST ROTATING BENEATH THE COLD CORE UPPER LOW OFF THE PAC NW COAST IS BEGINNING TO ENHANCE BAND OF PCPN ALONG THE FRONT. BOTH OF THESE FEATURES WILL BE MOVING INLAND TODAY...AND WE EXPECT AN INCREASE IN PCPN AS THE DAY WEARS ON. THERE HAS BEEN A BREAK IN THE PCPN OVER THE SIERNEV THIS MORNING AS LAST EVENING'S SHORT WAVE HAS MOVED EWD INTO THE GREAT BASIN. SUBSIDENCE IN THE WAKE OF THIS FEATURE HAS ALSO RESULTED IN PARTIAL CLEARING IN THE VALLEY. BUT LARGE SCALE ASCENT AND INSTABILITY WILL BE INCREASING OVER THE AREA WITH THE APPROACHING VORT LOBE TODAY AND SEASONABLY STRONG CYCLONIC CIRCULATION...AND SHOWERS WILL BE MOVING BACK/DEVELOPING IN THE VALLEY AND OVER THE SIERNEV TODAY. THE COLD CORE LOW HAS ALREADY RESULTED IN ZERO OR NEGATIVE LIFTED INDICES ON THE AREA MORNING RAOBS AND DIFFERENTIAL HEATING WILL STEEPEN LAPSE RATES THIS AFTERNOON. BUFKIT FORECAST SOUNDINGS FOR THE PROFILES FROM BAB/CIC SWD INCLUDING SAC/SCK STEEPEN LAPSE RATES INTO THE 8-10 DEG C/KM RANGE AT/BELOW 700 MBS THIS AFTERNOON. THE SRN MOST PROFILES ARE FAVORED DUE TO THE STRONGER CAA IN THIS AREA. THE STRONG INSTABILITY TODAY WOULD CERTAINLY FAVOR THUNDERSTORMS IN OUR AREA...HOWEVER...WITH THE UPPER LOW SO CLOSE TO OUR AREA...AND BASICALLY MOVING OVER THE REGION...WIND SHEAR PROFILES WILL NOT BE FULLY MAXIMIZED FOR THE POTENTIAL FOR ROTATING LOW-TOPPED STORMS. THIS IS PORTRAYED IN THE BUFKIT FORECAST PROFILES. WITH RELATIVELY WEAK PRESSURE GRADIENTS...AND THE PROXIMITY OF THE UPPER LOW...WE ARE NOT SEEING THE STRONG VEERING PROFILES WE WOULD LIKE TO SEE FOR STORM SCALE ROTATION...AND THIS APPEARS TO BE A LIMITING FACTOR FOR TODAY'S SEVERE POTENTIAL. THIS COULD CHANGE LOCALLY IF TOPOGRAPHIC INFLUENCES BACK THE LOWER LEVEL WINDS ALONG THE FAR E AND W SIDES OF THE SAC VLY. ALSO...THE SRN SAC/NRN SAN JOAQUIN VALLEY AND MOTHERLODE FOOTHILLS WOULD BE A FAVORED AREA FOR HAIL PRODUCING STORMS WHEN CONSIDERING THE LOCATION OF THE STRONGLY CYCLONIC UPPER LEVEL JET. WITH THE COLD CORE UPPER LOW DOMINATING THE REGION...THE FREEZING LEVEL/WBZ'S ARE ALSO RELATIVELY LOW...AND ON FACE VALUE...LOWER THAN THE OPTIMUM VALUE AROUND 9000 FT FOR LARGE HAIL. THE LOWER FREEZING LEVEL/WBZ'S WOULD FAVOR SMALLER HAIL...BUT THE POTENTIAL FOR MANY OF THE STORMS TO BE PRIMARILY SMALL HAIL PRODUCERS. JHM .PREVIOUS DISCUSSION... UPPER LEVEL LOW CENTERED OFF THE PACIFIC NORTHWEST CONTINUES ITS SLOW SOUTHEASTERLY DRIFT. A FRONTAL BOUNDARY HAS BECOME MORE PRONOUNCED OVERNIGHT... ELONGATING THE LOW CENTER AS IT ROTATES ALONG THE SOUTH SIDE OF THE FLOW. THE BOUNDARY IS JUST NOW COMING ONSHORE AND SOME SLIGHT ENHANCEMENT IS BEGINNING ON THE NORTHERN CA COAST. THIS SHOULD EXTEND DOWN THE COAST AND INLAND WITH TIME AS THE BOUNDARY FULLY MOVES ONSHORE. A COUPLE OF QUESTIONS ARE AT THE FOREFRONT FOR TODAY'S FORECAST... ONCE THIS BOUNDARY MOVES THROUGH NORCAL HOW MUCH OF A LULL WILL FOLLOW AND WILL WE GET A SECOND WAVE THIS AFTERNOON. THE FOLLOW UP QUESTION... DEPENDING UPON WHETHER WE GET MUCH OF A SECOND WAVE WILL WE HAVE ENOUGH CLEARING BETWEEN THE TWO BOUNDARIES TO HEAT UP THE LAND AND INTENSIFY THE DIFFERENTIAL HEATING AS THE UPPER LEVEL COLD AIR MOVES OVER THE AREA. THIS IS AN IMPORTANT COMPONENT TO THE CHANCE FOR THUNDERSTORMS TO DEVELOP THIS AFTERNOON. AS FOR THE FIRST QUESTION... AM EXPECTING SCATTERED SHOWERS ACROSS THE AREA AND A FRESH INCH OR TWO OF SNOW WITH THE FRONTAL PASSAGE THIS MORNING. THERE SHOULD BE LINGERING CLOUD COVER AND SPRINKLES/FLURRIES HERE AND THERE THROUGHOUT THE MORNING AS THE JET CROSSES TO THE SOUTH OF OUR AREA AND LEAVES OUR AIRMASS FAIRLY STAGNANT IN THE PROCESS. CURRENTLY THE SECOND BOUNDARY LOOKS TO MOVE THROUGH DURING THE EARLY TO MID AFTERNOON HOURS THOUGH IT IS TRENDING TO HAVE A GREATER IMPACT TO THE SOUTH OF US. REGARDS THUNDERSTORM DEVELOPMENT... IF THE JET DOES CONTINUE TO MOVE TO THE SOUTH IT LESSENS ITS CONTRIBUTION TO THE INSTABILITY THIS AFTERNOON BUT IT ALSO PULLS THE COLDER AIR FARTHER INTO THE REGION. WITH THE BETTER THAN EXPECTED HEATING THAT OCCURRED ON WEDNESDAY AND AT LEAST PEEK A BOO SUNSHINE EXPECTED TODAY... WE SHOULD SEE AT LEAST THE LEVEL OF THUNDERSTORM ACTIVITY WE SAW ON WEDNESDAY AND POSSIBLY STRONGER. WHILE THE ACTIVITY STAYED MOSTLY TO THE EAST SIDE OF THE VALLEY ON WEDNESDAY AM EXPECTING GOOD DELTA AREA DEVELOPMENT TODAY AND... IN GENERAL... ACTIVITY THAT IS MORE WIDESPREAD. IN THE HIGHER FOOTHILLS AND MOUNTAINS... IT IS LIKELY THAT SOME AREAS WILL RECEIVE FAIRLY HEAVY BURSTS OF SNOWFALL AS THESE SHOWERS MOVE THROUGH AND THUNDERSNOW IS A POSSIBILITY. THIS COULD ONCE AGAIN RESULT IN CHAIN CONTROLS ON THE MAJOR HIGHWAYS AND DANGEROUS DRIVING CONDITIONS FOR TRAVELERS HEADING OUT EARLY FOR THE HOLIDAY WEEKEND. SNOW LEVELS WILL BEGIN NEAR 5000 FEET AND LOWER TO NEAR 4000 FEET THROUGH THE DAY. A WINTER WEATHER ADVISORY GOES INTO EFFECT AT 5AM THIS MORNING AND CONTINUES THROUGH 1 AM ON FRIDAY. AS MENTIONED ABOVE... MOST OF THE SNOW WILL FALL WITH THE FRONTAL PASSAGE EARLY TO MID MORNING AND THEN AGAIN IN THE EARLY TO MID AFTERNOON.... THEN ASSOCIATED WITH WHERE THE SHOWER ACTIVITY DEVELOPS AND MOVES. THE BEST LULL IN THE WEATHER WILL BE IN LATE MORNING TO EARLY AFTERNOON AND WOULD BE THE BEST TIME FOR TRAVELERS TO TRY TO SLIP OUT OF TOWN TO AVOID THE WORST OF THE WEATHER EFFECTS. THE PRECIPITATION IS THE PRIMARY ITEM OF INTEREST FOR THIS EVENT. TEMPERATURES WILL BE A BIT COOLER ACROSS THE AREA COMPARED TO YESTERDAY AND WINDS A BIT BREEZIER... BUT NEITHER WILL BE AS NOTABLE AS THE POTENTIAL FOR THUNDERSTORMS AND ANOTHER LATE SEASON SNOWFALL. LINGERING RAIN AND SNOW OVER THE SIERRA RANGE INTO FRIDAY AND POSSIBLY WELL INTO FRIDAY IF THE JET HAS TOO MUCH SOUTHERLY AND NOT ENOUGH EASTERLY IN ITS FLOW AND WE END UP IN A WRAP AROUND SITUATION. REGARDLESS... THE HOLIDAY WEEKEND CONTINUES TO LOOK DRY AND RELATIVELY WARM. .EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)... A FLAT RIDGE PREVAILS THROUGH THE END OF THE HOLIDAY WEEKEND AND INTO THE WORK WEEK. ANOTHER SHOT AT PRECIPITATION COMES LATER IN THE WEEK BUT IT APPEARS WEAK AT THE THIS TIME. TEMPERATURES SHOULD APPROACH NORMAL FOR THIS TIME OF YEAR WHICH WILL SEEM DOWNRIGHT HOT COMPARED TO RECENT DAYS. && .AVIATION...UPPER LEVEL LOW WILL CONTINUE TO DIG OVER NORTHERN CALIFORNIA DURING THE NEXT 24 HOURS...WITH A COUPLE OF SHORT WAVES MOVING THROUGH THE REGION TODAY AND THIS EVENING. AS A RESULT... UNSETTLED WEATHER WILL CONTINUE ACROSS THE NORTHERN INTERIOR...WITH SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE. AT THIS TIME... PRIMARILY VFR CONDITIONS ARE PREVAILING IN THE VALLEY...WITH AREAS OF MVFR CONDITIONS IN SHOWERS. IN THE SURROUNDING MOUNTAINS...MVFR CONDITIONS ARE CONTINUING...WITH AREAS OF IFR/LIFR CONDITIONS POSSIBLE IN SHOWERS. SNOW LEVELS ARE RANGING BETWEEN 4500 FEET AND 5500 FEET THIS MORNING...AND WILL LOWER TO AROUND 4000 FEET BY THIS AFTERNOON. EXPECT CONDITIONS TO DETERIORATE THROUGH THE DAY. IN THE VALLEY...WIDESPREAD MVFR CONDITIONS IN SHOWERS WILL DEVELOP AFTER 20Z...WITH AREAS OF IFR CONDITIONS POSSIBLE IN THUNDERSTORMS BETWEEN 22Z AND 02Z...WHICH MAY AFFECT TAF LOCATIONS. IN THE SURROUND MOUNTAINS...EXPECT WIDESPREAD LIFR CONDITIONS TO DEVELOP AFTER 21Z....WITH HEAVY SNOW SHOWERS POSSIBLE AT TIMES. LOCAL SOUTHWEST WIND GUSTS UP TO 45 KNOTS WILL ALSO BE POSSIBLE OVER THE HIGHER MOUNTAIN PEAKS. EXPECT SOME IMPROVING CONDITIONS AFTER 06Z. && .STO WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY FROM 5 AM THURSDAY UNTIL 1 AM FRIDAY FOR THE WEST SLOPES OF THE NORTHERN SIERRA NEVADA AND FOR WESTERN PLUMAS COUNTY AND LASSEN PARK ABOVE 5000 FEET.. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SACRAMENTO CA 700 AM PDT THU MAY 27 2010 CAZ013>019-063-064-066>069-281400- SHASTA LAKE AREA/NORTHERN SHASTA COUNTY- BURNEY BASIN/EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY- CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY- CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY- MOUNTAINS SOUTHWESTERN SHASTA TO NORTHERN LAKE COUNTIES- CLEAR LAKE/SOUTHERN LAKE COUNTY-MOTHERLODE- EAST FOOTHILLS/NORTH SACRAMENTO VALLEY- WESTERN PLUMAS COUNTY/LASSEN PARK-WEST SLOPE NORTHERN SIERRA NEVADA- 700 AM PDT THU MAY 27 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA. .DAY ONE...TODAY ANOTHER ROUND OF LATE SEASON WINTRY WEATHER WILL MOVE THROUGH THE AREA TODAY AND TONIGHT AND A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE SIERRA NEVADA MOUNTAINS. IN ADDITION... THUNDERSTORMS ARE EXPECTED IN MOST PORTIONS OF INTERIOR NORTHERN CALIFORNIA. REFER TO THE FOLLOWING PRODUCTS FOR ADDITIONAL INFORMATION. * WINTER WEATHER ADVISORY.... SEE WWUS46 KSTO - WSWSTO FOR DETAILS * * ZONE FORECAST PRODUCT... .. SEE FPUS56 KSTO - ZFPSTO FOR DETAILS * .DAYS TWO THROUGH SEVEN... FRIDAY THROUGH WEDNESDAY SNOW SHOWERS WILL LINGER INTO FRIDAY IN THE SIERRA NEVADA MOUNTAINS WHICH WILL RESULT IN HAZARDOUS DRIVING CONDITIONS ON TRANS-SIERRA ROADWAYS. OTHERWISE... NO HAZARDOUS WEATHER IS EXPECTED THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE. THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET AT (LOWER CASE): HTTP://WWW.WEATHER.GOV/SACRAMENTO KJ
2 winter weather. Local standard time, as filed.
An additional three to six inches of snow fell in locations above 5000 feet with five to eight inches of snow falling along the crest. Locally gusty winds of 20 to 30 mph blew across the highest elevations.
An additional three to six inches of snow fell in locations above 5000 feet with five to eight inches of snow falling along the crest. Locally gusty winds of 20 to 30 mph blew across the highest elevations.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2010Every state in 2010This day in weather historyWarnings in California, May 2010
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 236781, 236782.