Area Forecast Discussion
FXUS66 KSTO [Sacramento/WFO CA] 111754 AFDSTO ∨
FXUS66 KSTO 111754 AFDSTO [HEAD]
National Weather Service Sacramento California 10:54am PDT Tue Mar 11 2014 ∨
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 1054 AM PDT TUE MAR 11 2014 [HEAD]
Synopsis. Building high pressure will result in dry weather and milder temperatures for the rest of the week. Breezy to strong northerly winds will continue into tonight. Winds will transition to more easterly overnight causing breezy winds along the Sierra Foothills and breezy to gusty across Lake County. ∨
.SYNOPSIS... BUILDING HIGH PRESSURE WILL RESULT IN DRY WEATHER AND MILDER TEMPERATURES FOR THE REST OF THE WEEK. BREEZY TO STRONG NORTHERLY WINDS WILL CONTINUE INTO TONIGHT. WINDS WILL TRANSITION TO MORE EASTERLY OVERNIGHT CAUSING BREEZY WINDS ALONG THE SIERRA FOOTHILLS AND BREEZY TO GUSTY ACROSS LAKE COUNTY. [DISC]
Discussion. Drier, warmer weather pattern settling into Northern California, but the primary concern today is wind. Strong north winds are developing in the Sacramento Valley and this event will be followed by strengthening easterly winds overnight that will impact the Sierra Foothills and higher elevations of Lake County. We have updated the Wind Advisory to include the strong overnight easterly winds for Lake County. ∨
.DISCUSSION... DRIER, WARMER WEATHER PATTERN SETTLING INTO NORCAL, BUT THE PRIMARY CONCERN TODAY IS WIND. STRONG NORTH WINDS ARE DEVELOPING IN THE SACRAMENTO VALLEY AND THIS EVENT WILL BE FOLLOWED BY STRENGTHENING EASTERLY WINDS OVERNIGHT THAT WILL IMPACT THE SIERRA FOOTHILLS AND HIGHER ELEVATIONS OF LAKE COUNTY. WE HAVE UPDATED THE WIND ADVISORY TO INCLUDE THE STRONG OVERNIGHT EASTERLY WINDS FOR LAKE COUNTY. [DISC]
Surface high pressure building into Oregon is increasing the north-south pressure gradient across the region. The MFR [Medford OR] to SAC [Sacramento CA] gradient has increased to 12.1 mbs as of 10am. Winds at Redding have just jumped in the past hour with sustained winds around 30–35 mph and gusts over 40 mph. Gusts around SAC [Sacramento CA] Metro region so far have been ranging 25–35 mph. Gusts across Lake County so far have ranged 20–45 mph. ∨
SURFACE HIGH PRESSURE BUILDING INTO OREGON IS INCREASING THE NORTH-SOUTH PRESSURE GRADIENT ACROSS THE REGION. THE MFR TO SAC GRADIENT HAS INCREASED TO 12.1 MBS AS OF 10 AM. WINDS AT REDDING HAVE JUST JUMPED IN THE PAST HOUR WITH SUSTAINED WINDS AROUND 30-35 MPH AND GUSTS OVER 40 MPH. GUSTS AROUND SAC METRO REGION SO FAR HAVE BEEN RANGING 25-35 MPH. GUSTS ACROSS LAKE COUNTY SO FAR HAVE RANGED 20-45 MPH. [DISC]
The north-south gradient peaks out around midday then gradually weakens into this evening. However, the east-west gradient tightens tonight, so the focus of stronger winds will shift towards the western Sierra slopes with breezy conditions reaching the foothills but just under advisory criteria. The greater concern for strong easterly winds will be across Lake County for elevations above 1000 ft. Strongest gusts will be near ridgetops of Lake County. Gradients relax Wednesday for lighter winds across the region. ∨
THE NORTH-SOUTH GRADIENT PEAKS OUT AROUND MIDDAY THEN GRADUALLY WEAKENS INTO THIS EVENING. HOWEVER, THE EAST-WEST GRADIENT TIGHTENS TONIGHT, SO THE FOCUS OF STRONGER WINDS WILL SHIFT TOWARDS THE WESTERN SIERRA SLOPES WITH BREEZY CONDITIONS REACHING THE FOOTHILLS BUT JUST UNDER ADVISORY CRITERIA. THE GREATER CONCERN FOR STRONG EASTERLY WINDS WILL BE ACROSS LAKE COUNTY FOR ELEVATIONS ABOVE 1000 FT. STRONGEST GUSTS WILL BE NEAR RIDGETOPS OF LAKE COUNTY. GRADIENTS RELAX WEDNESDAY FOR LIGHTER WINDS ACROSS THE REGION. [DISC]
Mild temperatures expected across Northern California through the remainder of the week though mountain valleys sheltered from the winds will see cool morning lows. ∨
MILD TEMPERATURES EXPECTED ACROSS NORCAL THROUGH THE REMAINDER OF THE WEEK THOUGH MOUNTAIN VALLEYS SHELTERED FROM THE WINDS WILL SEE COOL MORNING LOWS. [DISC]
Extended discussion (Saturday through Tuesday) ∨
.EXTENDED DISCUSSION (SATURDAY THROUGH TUESDAY) [DISC]
Upper level ridging spreads eastward into the region late this week, with temperatures peaking over the weekend. Well above normal temperatures are expected, with low 80s across much of the valley. Confidence is lower for next week, with models diverging on Monday. The models are 90° out of phase with ECMWF [European Center for Medium-Range Weather Forecasts model] showing NW flow aloft while the GFS [Global Forecast System: global spectral model used primarily for aviation weather forecasts; provides guidance out to 384 hours at 00, 06, 12 and 18UTC.] shows SW flow with a cutoff low [A closed upper-level low which has become completely displaced (cut off) from basic westerly current, and moves independently of that current. Cutoff lows may remain nearly stationary for days, or on occasion may move westward opposite to the prevailing flow aloft] offshore that creeps toward Southern California on Tuesday. Either way, the forecast should stay dry, but wind directions may be tricky. (Jclapp) ∨
UPPER LEVEL RIDGING SPREADS EASTWARD INTO THE REGION LATE THIS WEEK, WITH TEMPERATURES PEAKING OVER THE WEEKEND. WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED, WITH LOW 80S ACROSS MUCH OF THE VALLEY. CONFIDENCE IS LOWER FOR NEXT WEEK, WITH MODELS DIVERGING ON MONDAY. THE MODELS ARE 90 DEGREES OUT OF PHASE WITH ECMWF SHOWING NW FLOW ALOFT WHILE THE GFS SHOWS SW FLOW WITH A CUTOFF LOW OFFSHORE THAT CREEPS TOWARD SOCAL ON TUESDAY. EITHER WAY, THE FORECAST SHOULD STAY DRY, BUT WIND DIRECTIONS MAY BE TRICKY. JCLAPP [DISC]
High pressure dominates with VFR [Visual Flight Rules] today. Increasing low level wind today and continuing tonight, especially surface-030 AGL [Above Ground Level]. In Central Valley, local northerly surface wind up to 30 kts [35 mph] with gusts up to 40 kts [46 mph] today. Strongest wind expected from late this morning through afternoon from I-80 northward. Local N to E surface wind gusts 40–50 kts [46–58 mph] probable over Sierra and coastal range, peaking late this afternoon and tonight. ∨
HIGH PRESSURE DOMINATES WITH VFR TODAY. INCREASING LOW LEVEL WIND TODAY AND CONTINUING TONIGHT, ESPECIALLY SFC-030 AGL. IN CENTRAL VALLEY, LOCAL NORTHERLY SURFACE WIND UP TO 30 KTS WITH GUSTS UP TO 40 KTS TODAY. STRONGEST WIND EXPECTED FROM LATE THIS MORNING THROUGH AFTERNOON FROM I-80 NORTHWARD. LOCAL N TO E SURFACE WIND GUSTS 40 TO 50 KTS PROBABLE OVER SIERRA AND COASTAL RANGE, PEAKING LATE THIS AFTERNOON AND TONIGHT. [AVI2]
STO [Sacramento/WFO CA] Watches/Warnings/Advisories
.STO WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 8 PM PDT THIS EVENING CARQUINEZ STRAIT AND DELTA...CENTRAL SACRAMENTO VALLEY...NORTHERN SACRAMENTO VALLEY... SOUTHERN SACRAMENTO VALLEY. [WARN]
WIND ADVISORY UNTIL 5 AM PDT WEDNESDAY ABOVE 1000 FEET IN THE CLEAR LAKE/SOUTHERN LAKE COUNTY. [WRN2]
18 Miles E Groveland CA
10:40am PDT Mar 11 2014
This Afternoon. Sunny, with a high near 62°. NW wind around 6 mph.
Tonight. Clear, with a low around 34°. Breezy, with an ENE wind 13 to 18 mph increasing to 19 to 24 mph in the evening. Winds could gust as high as 37 mph.
Wednesday. Sunny, with a high near 61°. Breezy, with an east wind 13 to 23 mph, with gusts as high as 33 mph.
Wednesday Night. Mostly clear, with a low around 36°. ENE wind 8 to 13 mph.
Thursday. Sunny, with a high near 62°. ENE wind 6 to 11 mph becoming west in the morning.
Thursday Night. Mostly clear, with a low around 38°.
Friday. Sunny, with a high near 67°.
Friday Night. Mostly clear, with a low around 41°.
Saturday. Sunny, with a high near 69°.
Saturday Night. Mostly clear, with a low around 44°.
Sunday. Sunny, with a high near 71°.
Sunday Night. Partly cloudy, with a low around 43°.
Monday. Mostly sunny, with a high near 67°.