Area Forecast Discussion
FXUS66 KSTO [Sacramento/WFO CA] 202157 AFDSTO ∨
FXUS66 KSTO 202157 AFDSTO [HEAD]
National Weather Service Sacramento California 2:57pm PDT Mon Oct 20 2014 ∨
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 257 PM PDT MON OCT 20 2014 [HEAD]
Synopsis. Frontal system will continue cooler temperatures and precipitation chances through tonight. Thunderstorms are expected to continue into this evening, especially across the Sacramento Valley and Sierra Foothills. An elongated frontal system impacts Northern California with potential showers from Wednesday night into the weekend. ∨
.SYNOPSIS... FRONTAL SYSTEM WILL CONTINUE COOLER TEMPERATURES AND PRECIPITATION CHANCES THROUGH TONIGHT. THUNDERSTORMS ARE EXPECTED TO CONTINUE INTO THIS EVENING, ESPECIALLY ACROSS THE SACRAMENTO VALLEY AND SIERRA FOOTHILLS. AN ELONGATED FRONTAL SYSTEM IMPACTS NORTHERN CA WITH POTENTIAL SHOWERS FROM WEDNESDAY NIGHT INTO THE WEEKEND. [DISC]
Short term discussion (tonight through Thursday)… some strong showers have developed across the Sacramento Valley this afternoon. These storms have had relatively low tops at around 20–25K. Not too much shear or lightning strikes with these storms, so most storms will be heavy rain with outflow winds. These storm are not tall enough (cold enough) for much hail. Storm activity will continue tonight as the low center passes over Northern California, especially across the east valley and into the Sierra. ∨
.SHORT TERM DISCUSSION (TONIGHT THROUGH THURSDAY)... SOME STRONG SHOWERS HAVE DEVELOPED ACROSS THE SACRAMENTO VALLEY THIS AFTERNOON. THESE STORMS HAVE HAD RELATIVELY LOW TOPS AT AROUND 20-25K. NOT TOO MUCH SHEAR OR LIGHTNING STRIKES WITH THESE STORMS, SO MOST STORMS WILL BE HEAVY RAIN WITH OUTFLOW WINDS. THESE STORM ARE NOT TALL ENOUGH (COLD ENOUGH) FOR MUCH HAIL. STORM ACTIVITY WILL CONTINUE TONIGHT AS THE LOW CENTER PASSES OVER NORCAL, ESPECIALLY ACROSS THE EAST VALLEY AND INTO THE SIERRA. [DISC]
Flat ridging moves in Tuesday with some lingering clouds, but remaining dry. The next elongated frontal system will begin to bring light warm frontal precipitation to the Shasta Co. Area Wednesday night and spread southeastward Thursday, but still remaining northward of I-80. Temperatures will remain at or below seasonal norms. (Jclapp) ∨
FLAT RIDGING MOVES IN TUESDAY WITH SOME LINGERING CLOUDS, BUT REMAINING DRY. THE NEXT ELONGATED FRONTAL SYSTEM WILL BEGIN TO BRING LIGHT WARM FRONTAL PRECIP TO THE SHASTA CO. AREA WEDNESDAY NIGHT AND SPREAD SOUTHEASTWARD THURSDAY, BUT STILL REMAINING NORTHWARD OF I-80. TEMPERATURES WILL REMAIN AT OR BELOW SEASONAL NORMS. JCLAPP [DISC]
Extended discussion (Friday through Monday) a cooler and unsettled weather pattern will continue through the weekend. A low in the Gulf of Alaska will slowly move south and send disturbances inland over Northern California and the Pacific Northwest. The first such weather system will move over northwest California early Thursday and spread light showers across the northern Sacramento Valley by Thursday afternoon/evening. By the weekend, the main weather system will move inland over Oregon and Washington and spread more showers into Northern California. Some discrepancy exists in the models as to how much moisture/energy make it into the valley and how fast the system moves through. At this time, have continued the chance of showers in the forecast through the weekend. There's also a possibility of light snow accumulations Saturday night in the northern Sierra. Progressive pattern looks to continue into early next week, but timing and strength of systems is uncertain at this time. (Mead) ∨
.EXTENDED DISCUSSION (FRIDAY THROUGH MONDAY) A COOLER AND UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THE WEEKEND. A LOW IN THE GULF OF ALASKA WILL SLOWLY MOVE SOUTH AND SEND DISTURBANCES INLAND OVER NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST. THE FIRST SUCH WEATHER SYSTEM WILL MOVE OVER NORTHWEST CA EARLY THURSDAY AND SPREAD LIGHT SHOWERS ACROSS THE NORTHERN SACRAMENTO VALLEY BY THURSDAY AFTERNOON/EVENING. BY THE WEEKEND, THE MAIN WEATHER SYSTEM WILL MOVE INLAND OVER OREGON AND WASHINGTON AND SPREAD MORE SHOWERS INTO NORTHERN CALIFORNIA. SOME DISCREPANCY EXISTS IN THE MODELS AS TO HOW MUCH MOISTURE/ENERGY MAKE IT INTO THE VALLEY AND HOW FAST THE SYSTEM MOVES THROUGH. AT THIS TIME, HAVE CONTINUED THE CHANCE OF SHOWERS IN THE FORECAST THROUGH THE WEEKEND. THERE`S ALSO A POSSIBILITY OF LIGHT SNOW ACCUMULATIONS SATURDAY NIGHT IN THE NORTHERN SIERRA. PROGRESSIVE PATTERN LOOKS TO CONTINUE INTO EARLY NEXT WEEK, BUT TIMING AND STRENGTH OF SYSTEMS IS UNCERTAIN AT THIS TIME. MEAD [DISC]
Aviation. A cold front pushing through the northern valley with showers and the potential for isolated thunderstorms this afternoon and evening. These showers are resulting in MVFR [Marginal Visual Flight Rules] conditions over much of the northern valley with some local IFR [Instrument Flight Rules] near stronger storms. Erratic and gusty winds should also be expected near storms. Showers will linger over the Sierras until midnight, then mid level clouds will linger over the valley and mountains. (Mead) ∨
.AVIATION... A COLD FRONT PUSHING THROUGH THE NORTHERN VALLEY WITH SHOWERS AND THE POTENTIAL FOR ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THESE SHOWERS ARE RESULTING IN MVFR CONDITIONS OVER MUCH OF THE NORTHERN VALLEY WITH SOME LOCAL IFR NEAR STRONGER STORMS. ERRATIC AND GUSTY WINDS SHOULD ALSO BE EXPECTED NEAR STORMS. SHOWERS WILL LINGER OVER THE SIERRAS UNTIL MIDNIGHT, THEN MID LEVEL CLOUDS WILL LINGER OVER THE VALLEY AND MOUNTAINS. MEAD [AVIA]
STO [Sacramento/WFO CA] Watches/Warnings/Advisories
.STO WATCHES/WARNINGS/ADVISORIES... NONE. [WARN]
18 Miles E Groveland CA
2:40pm PDT Oct 20 2014
Tonight. A 20% chance of showers. Mostly cloudy, with a low around 44°. South wind 5 to 10 mph. New precipitation amounts of less than a tenth of an inch possible.
Tuesday. Mostly sunny, with a high near 61°. East wind around 5 mph becoming light and variable in the morning.
Tuesday Night. Mostly clear, with a low around 45°. West wind 5 to 7 mph becoming ENE in the evening.
Wednesday. Sunny, with a high near 66°. ENE wind around 8 mph becoming SW in the morning.
Wednesday Night. Mostly clear, with a low around 51°. West wind around 5 mph becoming ESE in the evening.
Thursday. Sunny, with a high near 68°.
Thursday Night. Mostly clear, with a low around 52°.
Friday. Sunny, with a high near 70°.
Friday Night. Partly cloudy, with a low around 51°.
Saturday. A chance of rain. Partly sunny, with a high near 59°.
Saturday Night. Partly cloudy, with a low around 42°.
Sunday. Mostly sunny, with a high near 60°.
Sunday Night. Mostly clear, with a low around 42°.
Monday. Mostly sunny, with a high near 64°.