Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
757 FXUS66 KHNX 110929 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 229 AM PDT Tue Mar 11 2025 && .KEY MESSAGES... 1. An Atmospheric River is favorable Wednesday into Thursday with significant precipitation for all of interior Central California. 2. A Winter Storm Warning has been issued for the Sierra Nevada due to heavy snowfall Tuesday night through Thursday night and a Winter Weather Advisory has been issued for the Lower Sierra Nevada for the same time period, and for the Kern County Mountains, including the Grapevine from Wednesday afternoon through Friday morning. 3. A High Wind Warning has been issued for the Mojave Desert Slopes and a Wind Advisory has been issued for the Kern County Desert due to strong winds in both areas from Wednesday morning through Friday afternoon. The High Wind Watch remains in effect for the West Side Hills. 4. Moderate to heavy rainfall is expected for the Sierra Nevada Foothills during the course of this system, and moderate rainfall can be expected for the San Joaquin Valley. && .DISCUSSION... A strong upper low moving towards Baja California is swinging some showers up into Kern County early this morning. This system is expected to just produce some light rainfall for the Kern County Mountains and Desert today. The probability of measureable rain ranges from 40 to 70 percent for Kern County through the evening hours. Tonight a quick moving ridge early before the next, more significant impact system, trough moves into Golden State and tracks across the state exiting early on Friday. A wide variety of impacts across all of Interior Central California throughout this system. Kern County Desert and Mojave Slopes wind impacts. The probability of exceeding (PoE) of 60 mph ranges from 40 to 70 percent on Thursday. Out in the desert the PoE of 45 mph ranges from 20 up to 70 percent from east to west across the Kern County Desert continuing into Friday along with the West Side Hills. High Wind warning for the Slopes and wind advisory for the desert look on track no adjustments at this time needed. No adjustment needed for Sierra snowfall. The 10th percentile, the lowest amount expected, comes in at 20 to 30 inches above 4000 feet for a storm total with the 00Z run. The high end, 10 percent chance, falls around 50 inch amount. The forecast in feet is very appropriate with this event and the Winter Storm needs no changes. The snow advisory for the Kern County Mountain passes and Tejon Pass the low end is near zero and the high end 3-4 inches. The PoE of 2 inches or more for the passes ranges from 37 percent for Tejon Pass ranges down to 16 percent for Tehachapi Pass. The wind and falling snow more than well justify the winter weather advisory highlight. Looking at 12 hour rainfall totals for the peak of the event on late Wednesday through Thursday first with a tenth of an inch. The PoE for a tenth lowest on the West Hills side of the San Joaqin Valley with 15 to 40 percent with the downsloping wind. On the east side of the valley 30 to 60 percent. The 24 hour PoE of 1/2 inch on the west side of the valley 25 to 60 percent with the period ending at 5 PM on Thursday and 50 to 90 percent for the east side of the valley. The PoE of one inch of rain for the foothills ranges from 90 to near 100 percent for the Wednesday and Thursday time frame. Looking at in low and high amounts taking Mariposa as the point of reference. The 24 hour precipitation range for the peak of the event from 5 AM Wednesday through 5 AM Thursday 1.49 to 2.66 inches of rainfall. The burn scars may have to contend with a threat of Thunderstorms on the back side of the event Thursday with probability of thunderstorms at eight to twelve percent. A low end probability. Strong mid-level lapse rates and low end CAPE along with TQ-Low top index all pointing a slim chance for storms. This could enhance rainfall briefly. The upper low helps carve out a large base trough over the western CONUS with northwest flow over California with waves shooting through the flow Friday into Saturday for more showers across the region. A quick ridge for Sunday then the next system arrives from the Pacific Monday last through next Tuesday for another event for the area. Temperature wise for the rest of the week into the weekend will be below normal with the very cold core system moving through. Sunday and Monday a trend up to closer to normal. The 6 to 10 day long range continues the below normal temperatures and above normal precipitation. As the forecast moves to 8 to 14 days the below normal temperatures continue however precipitation moves closer to normal for the season. && .AVIATION... 12Z Update: VFR conditions will prevail throughout the central California interior for the next 24 hours. && .AIR QUALITY ISSUES... ISSUED: 03/10/2025 13:56 EXPIRES: 03/11/2025 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 11 AM Wednesday to 5 PM PDT Friday for CAZ338. Wind Advisory from 11 AM Wednesday to 5 PM PDT Friday for CAZ337-339. High Wind Watch from Wednesday morning through Thursday evening for CAZ300-301-304-305-308-309-313. Winter Weather Advisory from 11 PM this evening to 11 PM PDT Thursday for CAZ318-320-322. Winter Storm Warning from 11 PM this evening to 11 PM PDT Thursday for CAZ323>331. Winter Weather Advisory from 5 PM Wednesday to 5 AM PDT Friday for CAZ333>336. && $$ Operations...Proton DSS..........DCH weather.gov/hanford