000
FXUS66 KSTO 242233
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
333 PM PDT FRI MAY 24 2013
.SHORT TERM DISCUSSION...
STRONG BLOCKING PATTERN OVER WRN NOAM WILL DOMINATE NORCAL WX
THROUGH THE HOLIDAY WEEKEND...IN WHAT COULD END-UP BEING "MEMORABLE"
IF THE MODELS AND FORECAST WX (ESPECIALLY QPF) VERIFY FOR OUR CWA.
MILD WSWLY FLOW S OF THE UPPER LOW OVER THE PAC NW WILL CONTINUE
INTO NORCAL ON SAT. A WEAK SHORT WAVE WILL ROTATE ACROSS THE FAR N
THROUGH THIS EVENING...SPREADING SOME HIGH CLOUDINESS OVER THE AREA.
BUT THE AIR MASS IS FORECAST TO REMAIN STABLE. THAT MAY CHANGE
SAT/SUN AFTERNOONS ACROSS THE FAR NRN MTNS WITH THE FORECAST OF
INCREASING INSTABILITY AS SUCCESSIVELY STRONGER SHORT WAVES MOVE
OVER THE AREA. MOISTURE IS MARGINAL SAT...BUT A LITTLE MORE MOISTURE
IS FORECAST ON SUN AND WE HAVE INCREASED THE AREAL COVERAGE OF
POPS WITH AN INCLUSION OF POSSIBLE THUNDER ERN SHASTA/WRN PLUMAS
COUNTIES INCLUDING LASSEN PARK AREA. SYNOPTIC COOLING WILL ALSO
LOWER MAX TEMPS ON SUN.
MON MAY TURN OUT TO CRACK THE TOP 5 WETTEST MEMORIAL DAYS IN DTS
(DOWNTOWN SAC) IF THE MODELS VERIFY. ENERGY FROM THE GULF OF AK IS
FORECAST TO PHASE WITH THE BLOCKING LOW...WITH THE ENERGY MOVING
SEWD MON/TUE OVER CA/NV. GREATER AREAL COVERAGE OF SHOWERS IS
EXPECTED ON MON/MON NITE...WITH VIRTUALLY ALL OF OUR CWA EXPECTED TO
SEE SOME SHOWERS. SHOWERS SHOULD DECREASE ON TUE. ANY QPF .08 INCH
OR MORE WOULD CRACK THE TOP 5 WETTEST MEMORIAL DAYS FOR DTS...AND
OUR LATEST QPF GRIDS SHOW A LITTLE MORE THAN A TENTH OF AN INCH
FOR THE MON PERIOD.
THE SREF PLUME AVERAGE TEMPS ARE FORECASTING SOME COOL MAXES FOR
MON AS WELL...AGAIN POSSIBLY CRACKING SOME OF THE TOP 5 COOLEST
MEMORIAL DAYS. HOWEVER...THE LATEST PLUME SPREADS HAVE BECOME
LESS CLUSTERED AROUND THE MEAN...RESULTING IN LOW CONFIDENCE THAT
A RECORD "COOL HIGH" WOULD OCCUR ON THAT DAY. IN ADDITION...THE
NAEFS TABLE SHOWS THE NEGATIVE ANOMALIES OF THE STANDARD PRESSURE
CHARTS OCCURRING IN THE VERY NEAR TERM WITH POSITIVE ANOMALIES
RETURNING SUN/MON. STILL...MAX TEMPS ARE FORECAST TO RANGE ABOUT
10 TO 16 DEG BELOW NORMAL ON MON. JHM
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)
TROUGH STARTS SHIFTING TO THE EAST ON TUESDAY TAPERING OFF THE
SHOWERS AND WARMING TEMPERATURES A FEW DEGREES. TEMPERATURES ARE
EXPECTED TO WARM INTO THE MID 70S IN THE VALLEY AND UPPER 40S TO
UPPER 50S IN THE MOUNTAINS. ANOTHER LOW MOVES INTO THE PACIFIC
NORTHWEST ON WEDNESDAY FOR CONTINUED CHANCE OF SHOWERS OVER THE
NORTHERN MOUNTAINS. TEMPERATURES WILL STILL REMAIN ABOUT 5 TO 10
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. THE LOW SHIFTS TO THE
EAST ON THURSDAY FOR A SLIGHT CHANCE OF LINGERING SHOWERS OVER THE
NORTHERN MOUNTAINS AND A LITTLE WARMER TEMPERATURES. THE 12Z
ECMWF BUILDS THE RIDGE OFF THE WEST COAST ON FRIDAY BUT THE 12Z
GFS KEEPS A BROAD TROUGH OVER THE AREA. BUT EITHER WAY IT LOOKS
LIKE IT MAY DRY FOR NEXT FRIDAY AND WARMER BUT HOW MUCH WARMER
WILL DEPEND ON HOW MUCH HEIGHTS RISE OVER THE AREA. THE FORECAST
FOR NOW WARMS TEMPERATURES IN THE MID 80S IN THE VALLEY AND 60S IN
THE MOUNTAINS WHICH IS NEARING NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION...
VFR CONDITIONS CONTINUE ACROSS INTERIOR NORTHERN CALIFORNIA
THROUGH SATURDAY. A WEAK WAVE WILL MOVE ACROSS THE FAR NORTH
TONIGHT INTO SATURDAY BRINGING MORE CLOUDS AND A SLIGHT CHANCE OF
SATURDAY AFTERNOON SHOWERS OVER THE NORTHERN MOUNTAINS. WINDS
GENERALLY 5 TO 15 KNOTS AT TAF SITES. LIGHT TO MODERATE WEST TO
SOUTHWEST WINDS OVER RIDGETOPS.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 241714
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1014 AM PDT FRI MAY 24 2013
.SHORT TERM DISCUSSION...
STRONG BLOCKING PATTERN OVER WRN NOAM WILL DOMINATE NORCAL WX
THROUGH THE HOLIDAY WEEKEND...IN WHAT COULD END-UP BEING "MEMORABLE"
IF THE MODELS AND FORECAST WX (ESPECIALLY QPF) VERIFY FOR OUR CWA.
FOR TODAY AND SAT...NORCAL WILL BE IN THE MILD WSWLY FLOW S OF
THE UPPER LOW OVER THE PAC NW. A WEAK SHORT WAVE WILL ROTATE
ACROSS THE FAR N TODAY SPREADING SOME HIGH CLOUDINESS OVER THE
AREA...BUT THE AIR MASS IS FORECAST TO REMAIN STABLE. THAT MAY
CHANGE SAT/SUN AFTERNOONS ACROSS THE FAR NRN MTNS WITH THE
FORECAST OF INCREASING INSTABILITY AS SUCCESSIVELY STRONGER SHORT
WAVES MOVE OVER THE AREA. MOISTURE IS MARGINAL SAT...BUT A LITTLE
MORE MOISTURE FORECAST ON SUN WITH SYNOPTIC COOLING ALSO LOWERING
TEMPS.
AS MENTIONED ABOVE...MON MAY TURN OUT TO CRACK THE TOP 5 WETTEST
MEMORIAL DAYS IN DTS (DOWNTOWN SAC) IF THE MODELS VERIFY. ENERGY
FROM THE GULF OF AK IS FORECAST TO PHASE WITH THE BLOCKING
LOW...WITH THE ENEGRY MOVING SEWD MON/TUE OVER CA/NV. GREATER
AREAL COVERAGE OF SHOWERS IS EXPECTED ON MON/MON NITE...GENERALLY
ENDING TUE...WITH VIRTUALLY ALL OF OUR CWA EXPECTED TO SEE SOME
SHOWERS. ANY QPF .08 INCH OR MORE WOULD CRACK THE TOP 5 WETTEST
MEMORIAL DAYS FOR DTS. THE SREF PLUME AVEARGE TEMPS ARE FORECASTING
SOME COOL MAXES FOR MON AS WELL...AGAIN POSSIBLY CRACKING SOME OF
THE TOP 5 COOLEST MEMORIAL DAYS. HOWEVER...THE LASTEST PLUME
SPREADS HAVE BECOME LESS CLUSTERED AROUND THE MEAN...RESULTING IN
LOW CONFIDENCE THAT A RECORD "COOL HIGH" WOULD OCCUR ON THAT DAY.
JHM
.PREVIOUS DISCUSSION...
NOT MUCH GOING ON IN THE ATMOSPHERE OVER NORTHERN CALIFORNIA
TODAY, BUT THE EARTH HAS BEEN ACTIVE LAST NIGHT AND INTO THIS
MORNING. FOLLOWING THE INITIAL 5.7 MAGNITUDE EARTHQUAKE ON THE
SOUTHEAST EDGE OF LAKE ALMANOR, THE AREA HAS HAD 40 AFTER SHOCKS
AS OF 415 AM PDT. THE LARGEST WAS 4.9 FELT AT OUR OFFICE IN
SACRAMENTO AROUND 100 AM PDT.
THE SEEMINGLY SEMI PERMANENT LOW OVER WASHINGTON IS STILL
DOMINATING OUR WEATHER PATTERN OVER NORTHERN CALIFORNIA. ROTATING
TROUGHS HAVE ELONGATED THE LOW FROM WEST TO EAST, TRANSLATING TO
A PLEASANT DAY WITH ONLY A FEW CLOUDS. TEMPERATURES ACROSS
NORTHERN CALIFORNIA WILL LIKELY BE AROUND 10F BELOW NORMAL TODAY.
THE NEXT SLIGHT CHANCE OF PRECIPITATION RETURNS SATURDAY
AFTERNOON INTO SUNDAY OVER THE NORTHERN MOUNTAINS AS ANOTHER WEAK
SHORTWAVE ROTATES AROUND THE LOW ACROSS NORTHERN CALIFORNIA. THIS
WILL ALSO INCREASE CLOUD COVER OVER THE FORECAST AREA.
INSTABILITY WITH THIS SYSTEM MAY BE ENOUGH TO TOUCH OFF A FEW
ISOLATED THUNDERSTORMS FROM THE BURNEY BASIN THROUGH WESTERN
PLUMAS COUNTY AND LASSEN PARK SUNDAY AFTERNOON.
A MUCH MORE ROBUST WEST TO NORTHWESTERLY JETSTREAM WILL HELP TO
FILL AND KICK OUT THE PAC NW LOW LATE SUNDAY. BUT THIS LOW/TROUGH
WILL BE REPLACED ON MEMORIAL DAY BY ANOTHER TROUGH FROM THE ERN
PAC WITH OVER AN INCH OF PRECIPITABLE WATER AND INCREASED UPPER
LEVEL DYNAMICS. IN LIGHT OF THIS, A GOOD CHANCE OF SHOWERS MAY
SPREAD ACROSS INTERIOR NORTHERN CALIFORNIA MONDAY AND CONTINUE
THROUGH TUESDAY. WE ARE NOT EXPECTING WIDESPREAD SIGNIFICANT
RAINFALL AMOUNTS, BUT BE AWARE THAT LOCALIZED HEAVIER AMOUNTS CAN
OCCUR WITHIN MORE INTENSE STORMS. SOME OF THE NORTHERN MOUNTAINS
AND COASTAL RANGE COULD RECEIVE UP TO 0.25 INCH WHILE THE VALLEY
WILL LIKELY REMAIN LESS THAN 0.1 INCH. EVEN THOUGH THE MAIN TROUGH
PASSES LATE TUESDAY, DIMINISHING SHOWERS MAY CONTINUE LATER INTO
THE WEEK.
AFTERNOON MAX TEMPERATURES WILL GRADUALLY WARM THROUGHOUT THE
WEEK, BUT STILL REMAIN JUST BELOW NORMAL. JCLAPP
&&
.EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)
A TROUGH REMAINS OVER THE WEST COAST NEXT WEEK BRINGING BELOW
NORMAL TEMPERATURES AND PERIODS OF POSSIBLE PRECIPITATION THROUGH
THE WEEK. THE MODELS ARE IN GOOD AGREEMENT WITH A DISTURBANCE
MOVING THROUGH NORTHERN CALIFORNIA ON MONDAY. THIS WILL BRING A
CHANCE OF RAIN TO INTERIOR NORTHERN CALIFORNIA ON MEMORIAL DAY.
TEMPERATURES ARE EXPECTED TO DROP TO AROUND 70 IN THE VALLEY AND
MID 40S TO MID 50S IN THE MOUNTAINS MONDAY. PRECIPITATION IS
EXPECTED TO TAPER OFF ON TUESDAY. MODELS VARY FOR THE REST OF THE
WEEK AND TIMING OF WAVES SO THERE IS UNCERTAINTY IN THE DETAILS.
FORECAST GOES WITH A CHANCE OF SHOWERS OVER NORTHERN SACRAMENTO VALLEY
AND NORTHERN MOUNTAINS AND A SLIGHT CHANCE OVER THE SIERRA FOR
WEDNESDAY AND THURSDAY WITH A POSSIBLE WAVE MOVING THROUGH THE
NORTH.
&&
.AVIATION...
VFR CONDITIONS CONTINUE. WINDS GENERALLY 5 TO 15 KNOTS AT TAF
SITES. LIGHT TO MODERATE WEST TO SOUTHWEST WINDS OVER RIDGETOPS. JBB
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 241138
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
438 AM PDT FRI MAY 24 2013
.DISCUSSION...
NOT MUCH GOING ON IN THE ATMOSPHERE OVER NORTHERN CALIFORNIA
TODAY, BUT THE EARTH HAS BEEN ACTIVE LAST NIGHT AND INTO THIS
MORNING. FOLLOWING THE INITIAL 5.7 MAGNITUDE EARTHQUAKE ON THE
SOUTHEAST EDGE OF LAKE ALMANOR, THE AREA HAS HAD 40 AFTER SHOCKS
AS OF 415 AM PDT. THE LARGEST WAS 4.9 FELT AT OUR OFFICE IN
SACRAMENTO AROUND 100 AM PDT.
THE SEEMINGLY SEMI PERMANENT LOW OVER WASHINGTON IS STILL
DOMINATING OUR WEATHER PATTERN OVER NORTHERN CALIFORNIA. ROTATING
TROUGHS HAVE ELONGATED THE LOW FROM WEST TO EAST, TRANSLATING TO
A PLEASANT DAY WITH ONLY A FEW CLOUDS. TEMPERATURES ACROSS
NORTHERN CALIFORNIA WILL LIKELY BE AROUND 10F BELOW NORMAL TODAY.
THE NEXT SLIGHT CHANCE OF PRECIPITATION RETURNS SATURDAY
AFTERNOON INTO SUNDAY OVER THE NORTHERN MOUNTAINS AS ANOTHER WEAK
SHORTWAVE ROTATES AROUND THE LOW ACROSS NORTHERN CALIFORNIA. THIS
WILL ALSO INCREASE CLOUD COVER OVER THE FORECAST AREA.
INSTABILITY WITH THIS SYSTEM MAY BE ENOUGH TO TOUCH OFF A FEW
ISOLATED THUNDERSTORMS FROM THE BURNEY BASIN THROUGH WESTERN
PLUMAS COUNTY AND LASSEN PARK SUNDAY AFTERNOON.
A MUCH MORE ROBUST WEST TO NORTHWESTERLY JETSTREAM WILL HELP TO
FILL AND KICK OUT THE PAC NW LOW LATE SUNDAY. BUT THIS LOW/TROUGH
WILL BE REPLACED ON MEMORIAL DAY BY ANOTHER TROUGH FROM THE ERN
PAC WITH OVER AN INCH OF PRECIPITABLE WATER AND INCREASED UPPER
LEVEL DYNAMICS. IN LIGHT OF THIS, A GOOD CHANCE OF SHOWERS MAY
SPREAD ACROSS INTERIOR NORTHERN CALIFORNIA MONDAY AND CONTINUE
THROUGH TUESDAY. WE ARE NOT EXPECTING WIDESPREAD SIGNIFICANT
RAINFALL AMOUNTS, BUT BE AWARE THAT LOCALIZED HEAVIER AMOUNTS CAN
OCCUR WITHIN MORE INTENSE STORMS. SOME OF THE NORTHERN MOUNTAINS
AND COASTAL RANGE COULD RECEIVE UP TO 0.25 INCH WHILE THE VALLEY
WILL LIKELY REMAIN LESS THAN 0.1 INCH. EVEN THOUGH THE MAIN TROUGH
PASSES LATE TUESDAY, DIMINISHING SHOWERS MAY CONTINUE LATER INTO
THE WEEK.
AFTERNOON MAX TEMPERATURES WILL GRADUALLY WARM THROUGHOUT THE
WEEK, BUT STILL REMAIN JUST BELOW NORMAL. JCLAPP
&&
.AVIATION...
GENERALLY VFR CONDITIONS FOR THE NEXT 24 HOURS. WINDS GENERALLY
BELOW 15 KNOTS.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
000
FXUS66 KSTO 240519
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1019 PM PDT THU MAY 23 2013
.SHORT TERM DISCUSSION...
UPPER LOW CONTINUES TO SPIN OVER WASHINGTON AND OREGON THIS
EVENING. THIS IS KEEPING A DRY...BUT COOL NORTHWEST FLOW OVER
NORCAL. TEMPERATURES AT 10 PM ARE GENERALLY IN THE LOW 60`S AT
VALLEY LOCATIONS. THESE READINGS ARE AROUND 5 DEGREES WARMER
VERSUS YESTERDAY AT THIS TIME. FORECASTED OVERNIGHT LOWS FROM THE
UPPER 40`S TO LOW 50`S LOOK ON TRACK AND NO EVENING UPDATE WILL
BE NEEDED.
AN EARTHQUAKE WAS FELT MODERATELY BY NUMEROUS PERSONS OVER
INTERIOR NORTHERN CALIFORNIA AT 847 PM PDT. TREMORS WHERE FELT A
FEW MINUTES AFTER THE INITIAL EARTHQUAKE. DAMAGE REPORTS SO
FAR HAVE ONLY BEEN OBJECTS FALLING FROM SHELVES AND DISHES
RATTLED OR BROKEN.
ACCORDING TO CALWAS REPORTS THE EPICENTER WAS NEAR GREENVILLE IN
PLUMAS COUNTY WITH A PRELIMINARY MAGNITUDE OF 5.7.
PREVIOUS DISCUSSION...
AN UPPER LEVEL LOW IS CURRENTLY CENTERED OVER THE PACIFIC
NORTHWEST. A WEAK WAVE HAS ROTATED AROUND THE LOW INTO NORTHERN NEVADA.
THIS TOUCHED OFF A FEW SHOWERS OVER EASTERN SHASTA...LASSEN PARK AND
PLUMAS COUNTY EARLIER TODAY BUT THESE HAVE SHIFTED EASTWARD.
TEMPERATURES HAVE WARMED TO THE LOW TO MID 70S IN THE VALLEY AND
MAY SEE A COUPLE MORE DEGREES OF WARMING BEFORE DAYLIGHT ENDS.
FRIDAY HIGHS WILL INCREASE AROUND ANOTHER 5 DEGREES AND STAY ABOUT
THE SAME FOR SATURDAY. SUNDAY MAY BE A DEGREE OR SO COOLER. THESE
TEMPERATURES ARE AT NEAR TO SLIGHTLY BELOW NORMAL LEVELS.
THE WEATHER FOR TONIGHT AND FRIDAY WILL REMAIN DRY. THE NEXT
SLIGHT CHANCE OF PRECIPITATION RETURNS SATURDAY AFTERNOON INTO
SUNDAY OVER THE NORTHERN MOUNTAINS AS A WEAK SHORTWAVE ROTATES
AROUND THE LOW ACROSS NORTHERN CALIFORNIA. THIS WILL ALSO INCREASE
CLOUD COVER SOME OVER THE FORECAST AREA. INSTABILITY WITH THIS
SYSTEM MAY BE ENOUGH TO TOUCH OFF A FEW ISOLATED THUNDERSTORMS
FROM THE BURNEY BASIN THROUGH WESTERN PLUMAS COUNTY AND LASSEN
PARK SUNDAY AFTERNOON AND EVENING. EK
&&
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
A TROUGH REMAINS OVER THE WEST COAST NEXT WEEK BRINGING BELOW
NORMAL TEMPERATURES AND PERIODS OF POSSIBLE PRECIPITATION THROUGH
THE WEEK. THE MODELS ARE IN GOOD AGREEMENT WITH A DISTURBANCE
MOVING THROUGH NORTHERN CALIFORNIA ON MONDAY. THIS WILL BRING A
CHANCE OF RAIN TO INTERIOR NORTHERN CALIFORNIA ON MEMORIAL DAY.
TEMPERATURES ARE EXPECTED TO DROP TO AROUND 70 IN THE VALLEY AND
MID 40S TO MID 50S IN THE MOUNTAINS MONDAY. PRECIPITATION IS
EXPECTED TO TAPER OFF ON TUESDAY. MODELS VARY FOR THE REST OF THE
WEEK AND TIMING OF WAVES SO THERE IS UNCERTAINTY IN THE DETAILS.
FORECAST GOES WITH A CHANCE OF SHOWERS OVER NORTHERN SACRAMENTO
VALLEY AND NORTHERN MOUNTAINS AND A SLIGHT CHANCE OVER THE SIERRA
FOR WEDNESDAY AND THURSDAY WITH A POSSIBLE WAVE MOVING THROUGH THE
NORTH.
&&
.AVIATION...
GENERALLY VFR CONDITIONS FOR THE NEXT 24 HOURS WITH A LOW PRESSURE
SYSTEM OVER THE PACIFIC NORTHWEST.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 232257
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
357 PM PDT THU MAY 23 2013
.SHORT TERM DISCUSSION...
AN UPPER LEVEL LOW IS CURRENTLY CENTERED OVER THE PACIFIC
NORTHWEST. A WEAK WAVE HAS ROTATED AROUND THE LOW INTO NORTHERN NEVADA.
THIS TOUCHED OFF A FEW SHOWERS OVER EASTERN SHASTA...LASSEN PARK AND
PLUMAS COUNTY EARLIER TODAY BUT THESE HAVE SHIFTED EASTWARD.
TEMPERATURES HAVE WARMED TO THE LOW TO MID 70S IN THE VALLEY AND
MAY SEE A COUPLE MORE DEGREES OF WARMING BEFORE DAYLIGHT ENDS.
FRIDAY HIGHS WILL INCREASE AROUND ANOTHER 5 DEGREES AND STAY ABOUT
THE SAME FOR SATURDAY. SUNDAY MAY BE A DEGREE OR SO COOLER. THESE
TEMPERATURES ARE AT NEAR TO SLIGHTLY BELOW NORMAL LEVELS.
THE WEATHER FOR TONIGHT AND FRIDAY WILL REMAIN DRY. THE NEXT
SLIGHT CHANCE OF PRECIPITATION RETURNS SATURDAY AFTERNOON INTO
SUNDAY OVER THE NORTHERN MOUNTAINS AS A WEAK SHORTWAVE ROTATES
AROUND THE LOW ACROSS NORTHERN CALIFORNIA. THIS WILL ALSO INCREASE
CLOUD COVER SOME OVER THE FORECAST AREA. INSTABILITY WITH THIS
SYSTEM MAY BE ENOUGH TO TOUCH OFF A FEW ISOLATED THUNDERSTORMS
FROM THE BURNEY BASIN THROUGH WESTERN PLUMAS COUNTY AND LASSEN
PARK SUNDAY AFTERNOON AND EVENING. EK
&&
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
A TROUGH REMAINS OVER THE WEST COAST NEXT WEEK BRINGING BELOW
NORMAL TEMPERATURES AND PERIODS OF POSSIBLE PRECIPITATION THROUGH
THE WEEK. THE MODELS ARE IN GOOD AGREEMENT WITH A DISTURBANCE
MOVING THROUGH NORTHERN CALIFORNIA ON MONDAY. THIS WILL BRING A
CHANCE OF RAIN TO INTERIOR NORTHERN CALIFORNIA ON MEMORIAL DAY.
TEMPERATURES ARE EXPECTED TO DROP TO AROUND 70 IN THE VALLEY AND
MID 40S TO MID 50S IN THE MOUNTAINS MONDAY. PRECIPITATION IS
EXPECTED TO TAPER OFF ON TUESDAY. MODELS VARY FOR THE REST OF THE
WEEK AND TIMING OF WAVES SO THERE IS UNCERTAINTY IN THE DETAILS.
FORECAST GOES WITH A CHANCE OF SHOWERS OVER NORTHERN SACRAMENTO VALLEY
AND NORTHERN MOUNTAINS AND A SLIGHT CHANCE OVER THE SIERRA FOR
WEDNESDAY AND THURSDAY WITH A POSSIBLE WAVE MOVING THROUGH THE
NORTH.
&&
.AVIATION...
GENERALLY VFR CONDITIONS FOR THE NEXT 24 HOURS WITH A LOW PRESSURE
SYSTEM OVER THE PACIFIC NORTHWEST.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 231638
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
938 AM PDT THU MAY 23 2013
.SHORT TERM DISCUSSION...
A GENERAL UPPER LEVEL LOW PATTERN OVER THE REGION LOOKS LIKE IT
WILL BE A PERSISTENT FEATURE FOR THE FORESEEABLE FUTURE BRINGING
RELATIVELY COOL TEMPERATURES. REINFORCING SHORTWAVES WILL ALSO
BRING THE POSSIBILITY OF PRECIPITATION AT TIMES...ESPECIALLY EARLY
NEXT WEEK.
THE UPPER LEVEL LOW IS CURRENTLY CENTERED OVER THE PACIFIC
NORTHWEST. A WEAK WAVE IS ROTATING AROUND THE LOW OVER NORTHERN
CALIFORNIA TODAY. SATELLITE SHOWS A LIMITED ENHANCED AREA MOVING
FROM NE CALIFORNIA INTO NW NEVADA. RADAR INDICATES JUST A FEW
LIGHT RETURNS OVER EASTERN SHASTA...LASSEN PARK AND PLUMAS COUNTY.
HRRR MODEL SUGGESTS THAT JUST A FEW ISOLATED SHOWERS WILL OCCUR
THROUGH MID DAY WITH EVEN CLOUDS DIMINISHING BY AFTERNOON. WILL
UPDATE FORECAST TO REDUCE CLOUD COVER AND COVERAGE OF SHOWERS FOR
THE REST OF TODAY.
WILL INCREASE AFTERNOON TEMPERATURES TODAY A COUPLE DEGREES OVER
THE AREA...ESPECIALLY OVER THE NORTHERN SACRAMENTO VALLEY. MORNING
TEMPERATURES IN SOME SPOTS ARE STARTING RELATIVELY COOL BUT SHOULD
INCREASE AS HEIGHTS REBOUND IN THE WAKE OF THE DEPARTING SHORTWAVE
TROUGH. CLOUD COVER ALSO LOOKS LIKE IT WILL BE A LITTLE MORE
LIMITED OVER THE NORTHERN PORTION OF THE FORECAST AREA AND WILL
ALLOW MORE SOLAR HEATING. TEMPERATURES AT REDDING ARE ALREADY 6
DEGREES WARMER THAN YESTERDAY.
WINDS WILL GENERALLY BE LIGHTER TODAY ALTHOUGH THERE WILL BE SOME
BREEZY NORTH WINDS AT TIMES OVER THE NORTHERN SACRAMENTO VALLEY
THIS AFTERNOON AND UP IN THE HIGHER SIERRA. EK
&&
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
A MEAN TROUGH WILL LINGER OVER THE WEST COAST THROUGH THE WEEKEND
AND INTO THE FIRST PART OF NEXT WEEK. SEVERAL WEAK DISTURBANCES
WILL MOVE THROUGH THE LONGWAVE TROUGH AND BRUSH FAR NORTHERN
CALIFORNIA. MODELS ARE NOT IN AGREEMENT HOWEVER WITH THE
AMPLITUDE AND TIMING OF THESE FEATURES. THE ECMWF SOLUTION HAS
THE LEAST IMPACT FOR US AS IT IS LESS AMPLIFIED WITH THE LONGWAVE
TROUGH AND CONSEQUENTLY KEEPS OUR AREA DRY THROUGH THE PERIOD.
THE GFS AND GEM MEANWHILE HAVE COMPACT SHORTWAVES MOVING THROUGH
SATURDAY NIGHT AND MONDAY NIGHT...WITH LINGERING MOUNTAIN SHOWERS
IN-BETWEEN. THE GFS IS EVEN SHOWING SOME CHANCE OF CONVECTION
SATURDAY NIGHT FOR THE COASTAL MOUNTAINS AND LASSEN VICINITY. WITH
LIMITED CERTAINTY...HAVE OPTED FOR A SLIGHT CHANCE OF SHOWERS
THROUGH THE PERIOD OVER THE MOUNTAINS FROM AROUND RED BLUFF
NORTHWARD. HAVE ADDED A MENTION OF THUNDER SAT AFTERNOON/EVENING
TO ACCOUNT FOR SFC-BASED INSTABILITY PROGGED BY THE GFS...WHICH
ALSO HAPPENS TO MATCH UP WELL WITH NEIGHBORING FORECAST OFFICES.
REGARDLESS OF WHICH SOLUTION VERIFIES...THE ONLY IMPACT FOR THE
CENTRAL VALLEY WOULD BE CONTINUED SEASONAL TEMPERATURES WITH
ONSHORE FLOW AND A FEW CLOUDS. -DVC
&&
.AVIATION...
VFR CONDITIONS CONTINUE NEXT 24 HOURS FOR INTERIOR NORCAL TAF
SITES. NORTH WINDS LESS THAN 15 KNOTS TODAY BECOMING VARIABLE TO
10 KNOTS AFTER ABOUT 03Z.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 231047
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
347 AM PDT THU MAY 23 2013
.DISCUSSION...
THE QUASI (NEAR) STATIONARY LOW IS STILL POSITIONED OVER THE
WASHINGTON/NRN OREGON AREA. THE MODELS ARE IN GOOD AGREEMENT WITH
A SHORT WAVE TROUGH AXIS MOVING THROUGH NRN CAL THIS MORNING. SO
FAR, THE SHORT WAVE TROUGH IS NOT ALL THAT IMPRESSIVE AS CLOUD
ENHANCEMENT IS NOT TAKING PLACE OVER NRN CAL, IN THE DIVERGENT
REGION OF THE TROUGH. HOWEVER, ENHANCEMENT MAY OCCUR LATE THIS
MORNING AND INTO AFTERNOON DUE TO INCREASED LOW LEVEL THERMAL
INSTABILITY AND OROGRAPHIC LIFTING EFFECTS OVER SHASTA COUNTY DOWN
INTO WRN PLUMAS. WE HAVE ISOLATED SHOWERS FOR THIS SAME REGION
BEGINNING AROUND NOON. THE INSTABILITY IS NOT VERY IMPRESSIVE IN
PART DUE TO CLOUD COVER, SO WE LEFT OUT THE MENTION OF
THUNDERSTORMS.
THIS PARENT QUASI STATIONARY LOW WILL BECOME OBLONG TODAY WITH
LESS CYCLONIC FLOW OVER NRN CAL FRIDAY. THIS TRANSLATES TO LESS
CLOUDS, NO SHOWER ACTIVITY, AND SLIGHTLY WARMER TEMPERATURES.
FURTHER OUT...SEVERAL MORE REINFORCING SHORT WAVE TROUGHS COME OFF THE
NE PACIFIC...ONE SATURDAY INTO SUNDAY THAT BRINGS ANOTHER CHANCE
OF SHOWER ACTIVITY TO THE NRN MOUNTAIN REGION...AND THE NEXT
COUPLE REINFORCING WAVES IMPACT MUCH OF THE REGION NEXT WEEK WITH
A CHANCE OF LIGHT SHOWER ACTIVITY. THE MODELS ARE DIGGING THESE
WAVES A BIT DEEPER INTO CENTRAL AND SRN CAL WITH INCREASED UPPER
LEVEL DYNAMICS AND COOL TEMPERATURES, BUT THE TIMING AND EXACT
PLACEMENT IS STILL A BIT SQUIRRELY AT THIS POINT. JCLAPP
&&
.AVIATION...
VFR CONDITIONS CONTINUE NEXT 24 HOURS FOR INTERIOR NORCAL TAF
SITES. NORTH WINDS LESS THAN 15 KNOTS TODAY BECOMING VARIABLE TO
10 KNOTS AFTER ABOUT 03Z.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
000
FXUS66 KSTO 230457
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
957 PM PDT WED MAY 22 2013
.SHORT TERM DISCUSSION...
UPPER LOW CONTINUES TO SPIN OVER WASHINGTON AND OREGON THIS
EVENING. THIS IS KEEPING A DRY...BUT COOL NORTHWEST FLOW OVER
NORCAL. THE BREEZY NORTH WINDS OF EARLIER TODAY HAVE DIMINISHED
AND LIGHT WINDS WILL PREVAIL FOR THE REST OF THE NIGHT.
TEMPERATURES AT 9 PM ARE GENERALLY IN THE LOW 60`S AND 50`S AT
VALLEY LOCATIONS. THESE READINGS ARE AROUND 5 DEGREES COOLER
VERSUS YESTERDAY AT THIS TIME. FORECASTED OVERNIGHT LOWS FROM THE
LOW 40`S TO LOW 50`S LOOK ON TRACK AND NO EVENING UPDATE WILL BE
NEEDED.
PREVIOUS DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT WITH THE UPPER-LEVEL TROUGH AXIS
MOVING EAST OF NORTHERN CALIFORNIA TONIGHT...WITH A NORTHWEST FLOW
ALOFT BEHIND THE TROUGH AXIS. THIS WILL KEEP A COOL AIRMASS OVER THE
NORTHERN CALIFORNIA INTERIOR...WITH TEMPERATURES REMAINING A FEW
DEGREES BELOW NORMAL THROUGH FRIDAY.
SOME MODERATION OF THE AIRMASS IS EXPECTED BY THE END OF THE WEEK
AND OVER THE WEEKEND AS THE PACNW LOW WEAKENS AND LIFTS OUT TO THE
NORTHEAST. HOWEVER...IT/S LOOKING LIKE MORE ENERGY WILL WORK
ACROSS THE PACIFIC EARLY NEXT WEEK REINFORCING THE TROUGH ALONG
THE WEST COAST AND PERHAPS BRINGING A BETTER CHANCE OF SHOWERS
FURTHER SOUTH. STAY TUNED.
&&
.AVIATION...
VFR CONDITIONS CONTINUE NEXT 24 HOURS FOR INTERIOR NORCAL TAF SITES.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
000
FXUS66 KSTO 222243
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
330 PM PDT WED MAY 22 2013
.DISCUSSION...
SATELLITE LOOPS SHOW THE UPPER-LEVEL LOW OVER WASHINGTON AND OREGON
THIS AFTERNOON WITH THE ASSOCIATED TROUGH MOVING INTO NORTHERN AND
CENTRAL CALIFORNIA. SURFACE WINDS INCREASED THIS MORNING AND HAVE
APPROACHED ADVISORY CRITERIA AT TIMES...SO WILL KEEP THE CURRENT
WIND ADVISORY IN PLACE THROUGH 00Z THURSDAY /1700 PDT THIS
AFTERNOON/.
THE MODELS ARE IN GOOD AGREEMENT WITH THE UPPER-LEVEL TROUGH AXIS
MOVING EAST OF NORTHERN CALIFORNIA TONIGHT...WITH A NORTHWEST FLOW
ALOFT BEHIND THE TROUGH AXIS. THIS WILL KEEP A COOL AIRMASS OVER THE
NORTHERN CALIFORNIA INTERIOR...WITH TEMPERATURES REMAINING A FEW
DEGREES BELOW NORMAL THROUGH FRIDAY.
SOME MODERATION OF THE AIRMASS IS EXPECTED BY THE END OF THE WEEK
AND OVER THE WEEKEND AS THE PACNW LOW WEAKENS AND LIFTS OUT TO THE
NORTHEAST. HOWEVER...IT/S LOOKING LIKE MORE ENERGY WILL WORK
ACROSS THE PACIFIC EARLY NEXT WEEK REINFORCING THE TROUGH ALONG
THE WEST COAST AND PERHAPS BRINGING A BETTER CHANCE OF SHOWERS
FURTHER SOUTH.
&&
.AVIATION...
VFR CONDS CONT NXT 24 HRS FOR INT NORCAL TAF SITES. BREEZY NORTH
WINDS 12 TO 18 KNOTS DECREASING THIS EVENING WITH ISOLATED VALLEY
GUSTS TO AROUND 20 KNOTS THRU ABOUT 03Z THU.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SANGER
WWW.WRH.NOAA.GOV/STO
000
FXUS66 KSTO 222230
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
330 PM PDT WED MAY 22 2013
.DISCUSSION...
SATELLITE LOOPS SHOW THE UPPER-LEVEL LOW OVER WASHINGTON AND OREGON
THIS AFTERNOON WITH THE ASSOCIATED TROUGH MOVING INTO NORTHERN AND
CENTRAL CALIFORNIA. SURFACE WINDS INCREASED THIS MORNING AND HAVE
APPROACHED ADVISORY CRITERIA AT TIMES...SO WILL KEEP THE CURRENT
WIND ADVISORY IN PLACE THROUGH 00Z THURSDAY /1700 PDT THIS
AFTERNOON/.
THE MODELS ARE IN GOOD AGREEMENT WITH THE UPPER-LEVEL TROUGH AXIS
MOVING EAST OF NORTHERN CALIFORNIA TONIGHT...WITH A NORTHWEST FLOW
ALOFT BEHIND THE TROUGH AXIS. THIS WILL KEEP A COOL AIRMASS OVER THE
NORTHERN CALIFORNIA INTERIOR...WITH TEMPERATURES REMAINING A FEW
DEGREES BELOW NORMAL THROUGH FRIDAY.
SOME MODERATION OF THE AIRMASS IS EXPECTED BY THE END OF THE WEEK
AND OVER THE WEEKEND AS THE PACNW LOW WEAKENS AND LIFTS OUT TO THE
NORTHEAST. HOWEVER...IT/S LOOKING LIKE MORE ENERGY WILL WORK
ACROSS THE PACIFIC EARLY NEXT WEEK REINFORCING THE TROUGH ALONG
THE WEST COAST AND PERHAPS BRINGING A BETTER CHANCE OF SHOWERS
FURTHER SOUTH.
&&
.AVIATION...
VFR CONDS CONT NXT 24 HRS FOR INT NORCAL TAF SITES. BREEZY NORTH
WINDS 12 TO 18 KNOTS DECREASING THIS EVENING WITH ISOLATED VALLEY
GUSTS TO AROUND 20 KNOTS THRU ABOUT 03Z THU.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 5 PM PDT THIS AFTERNOON CARQUINEZ STRAIT AND
DELTA...CENTRAL SACRAMENTO VALLEY...NORTHERN SAN JOAQUIN
VALLEY...SOUTHERN SACRAMENTO VALLEY.
&&
$$
SANGER
WWW.WRH.NOAA.GOV/STO
000
FXUS66 KSTO 221734
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1034 AM PDT WED MAY 22 2013
.UPDATE...
WINDS HAVE INCREASED THIS MORNING...WITH A FEW SITES ALREADY
REACHING WIND ADVISORY CRITERIA. WINDS ARE EXPECTED TO INCREASE
THROUGH MIDDAY AS THE LOW PRESSURE TROUGH MOVES THROUGH NORTHERN
AND CENTRAL CALIFORNIA. WINDS WILL BEGIN TO SUBSIDE LATE THIS
AFTERNOON. HAVE ISSUED A WIND ADVISORY FOR THE CENTRAL AND
SOUTHERN SACRAMENTO VALLEY...THE CARQUINEZ STRAT AND DELTA...AND
THE NORTHERN SAN JOAQUIN VALLEY THROUGH 00Z THURSDAY /1700 PDT
THIS AFTERNOON/.
&&
.DISCUSSION...
COLD UPPER LOW SETTLING IN OVER THE PACNW WHERE IT WILL REMAIN
FOR THE NEXT SEVERAL DAYS. THE MAIN IMPACT ON OUR REGION/S WEATHER
WILL BE COOLER TEMPERATURES AND BREEZY CONDITIONS THAT CAN BE
EXPECTED THROUGH THE END OF THE WEEK AS THE PATTERN CHANGES
LITTLE. THE MAIN THREAT FOR SHOWERS OVER THE NEXT SEVERAL DAYS
WILL REMAIN NEAR THE OREGON BORDER AND AREAS FURTHER TO THE NORTH
CLOSER TO THE LOW CENTER...THOUGH A FEW SHOWERS WILL BE POSSIBLE
AS FAR SOUTH AS THE FAR NORTHERN SIERRA ON THURSDAY AS A STRONGER
SHORT- WAVE ROTATES THROUGH.
TEMPERATURES WILL CONTINUE TO COOL TODAY FOLLOWING THE INITIAL
SURGE OF COOLER AIR SOUTHWARD ON TUESDAY. HIGHS TODAY WILL BE
ANOTHER 5 TO 10 DEGREES COOLER IN MOST AREAS COMPARED TO TUESDAY.
WINDS ARE EXPECTED TO BE LESS BREEZY THAN TUESDAY EVENING AS
NORTHERLY SURFACE PRESSURE GRADIENTS RELAX A BIT...HOWEVER
CONTINUING COLD ADVECTION WILL KEEP SOME BREEZES GOING INTO
THURSDAY.
SOME MODERATION OF THE AIRMASS IS EXPECTED BY THE END OF THE WEEK
AND OVER THE WEEKEND AS THE PACNW LOW WEAKENS AND LIFTS OUT TO THE
NORTHEAST. HOWEVER...IT/S LOOKING LIKE MORE ENERGY WILL WORK
ACROSS THE PACIFIC EARLY NEXT WEEK REINFORCING THE TROUGH ALONG
THE WEST COAST AND PERHAPS BRINGING A BETTER CHANCE OF SHOWERS
FURTHER SOUTH. STAY TUNED.
&&
.AVIATION...
VFR CONDS CONT NXT 24 HRS FOR INT NORCAL TAF SITES. BREEZY NORTH
WINDS 15 TO 22 KNOTS WITH VALLEY GUSTS TO AROUND 28 KNOTS THRU TDA DECREASING
AFT ABOUT 03Z THU.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 5 PM PDT THIS AFTERNOON CARQUINEZ STRAIT AND
DELTA...CENTRAL SACRAMENTO VALLEY...NORTHERN SAN JOAQUIN
VALLEY...SOUTHERN SACRAMENTO VALLEY.
&&
$$
SANGER /FOR WFO SACRAMENTO/
000
FXUS66 KSTO 221051
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
351 AM PDT WED MAY 22 2013
.DISCUSSION...
COLD UPPER LOW SETTLING IN OVER THE PACNW WHERE IT WILL REMAIN
FOR THE NEXT SEVERAL DAYS. THE MAIN IMPACT ON OUR REGION/S WEATHER
WILL BE COOLER TEMPERATURES AND BREEZY CONDITIONS THAT CAN BE
EXPECTED THROUGH THE END OF THE WEEK AS THE PATTERN CHANGES
LITTLE. THE MAIN THREAT FOR SHOWERS OVER THE NEXT SEVERAL DAYS
WILL REMAIN NEAR THE OREGON BORDER AND AREAS FURTHER TO THE NORTH
CLOSER TO THE LOW CENTER...THOUGH A FEW SHOWERS WILL BE POSSIBLE
AS FAR SOUTH AS THE FAR NORTHERN SIERRA ON THURSDAY AS A STRONGER
SHORT- WAVE ROTATES THROUGH.
TEMPERATURES WILL CONTINUE TO COOL TODAY FOLLOWING THE INITIAL
SURGE OF COOLER AIR SOUTHWARD ON TUESDAY. HIGHS TODAY WILL BE
ANOTHER 5 TO 10 DEGREES COOLER IN MOST AREAS COMPARED TO TUESDAY.
WINDS ARE EXPECTED TO BE LESS BREEZY THAN TUESDAY EVENING AS
NORTHERLY SURFACE PRESSURE GRADIENTS RELAX A BIT...HOWEVER
CONTINUING COLD ADVECTION WILL KEEP SOME BREEZES GOING INTO
THURSDAY.
SOME MODERATION OF THE AIRMASS IS EXPECTED BY THE END OF THE WEEK
AND OVER THE WEEKEND AS THE PACNW LOW WEAKENS AND LIFTS OUT TO THE
NORTHEAST. HOWEVER...IT/S LOOKING LIKE MORE ENERGY WILL WORK
ACROSS THE PACIFIC EARLY NEXT WEEK REINFORCING THE TROUGH ALONG
THE WEST COAST AND PERHAPS BRINGING A BETTER CHANCE OF SHOWERS
FURTHER SOUTH. STAY TUNED.
&&
.AVIATION...
VFR CONDS CONT NXT 24 HRS FOR INT NORCAL TAF SITES. BREEZY NORTH
WINDS 10 TO 20 KNOTS THRU TDA DECREASING AFT ABOUT 08Z THU.
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
000
FXUS66 KSTO 220421
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
921 PM PDT TUE MAY 21 2013
.SHORT TERM DISCUSSION...
LOW PRESSURE AREA CENTERED ALONG THE WESTERN WASHINGTON OREGON
BORDER THIS EVENING HAS GENERATED A FEW LIGHT SHOWERS OVER THE FAR
NORTH AND NORTHWEST PART OF THE STATE THIS EVENING AND BREEZY
NORTHWEST WINDS FOR MOST AREAS. THE DELTA STILL HAVE SOUTHWEST
FLOW INTO THE SACRAMENTO VALLEY...BUT THAT IS EXPECTED TO TURN TO
THE NORTHWEST LATER TONIGHT. TEMPERATURES ARE RUNNING MUCH COOLER
THAN 24 HOURS AGO WITH MOST AREAS DOWN BY 10 TO 20 DEGREES FROM
THIS TIME LAST NIGHT. WINDS MAY HELP TO KEEP SOME TEMPERATURES IN
THE MID 50S OVERNIGHT WHILE OTHER AREAS WHERE WINDS ARE NOT THAT
STRONG WILL DROP OFF INTO THE MID TO UPPER 40S IN THE CENTRAL
VALLEY.
THERE IS PLENTY OF COLD AIR ADVECTION THAT WILL BE FILTERING INTO
THE REGION OVERNIGHT THAT SHOULD HELP TO KEEP SOME WINDS GOING ALL
NIGHT LONG AND CONDITIONS BREEZY ON WEDNESDAY. TEMPERATURES WILL
CONTINUE TO COOL ON WEDNESDAY ONLY REACHING THE LOW TO MID 70S FOR
MOST VALLEY LOCATIONS TO THE 50S FOR MOST MOUNTAIN LOCATIONS. THE
FLOW OVER NORTHERN CALIFORNIA WILL REMAIN FAIRLY DRY SO OTHER THAN
THE EXTREME NORTHERN PART OF THE STATE MOST NORTHERN MOUNTAIN
AREAS AROUND SHASTA COUNTY SHOULD CONTINUE TO REMAIN DRY.
A SHORTWAVE WILL ROTATE THROUGH THE BASE OF THE TROUGH ON
WEDNESDAY WITH ANOTHER ONE THAT WILL ROTATE THROUGH A LITTLE
FURTHER SOUTH FOR THURSDAY. AS THAT SECOND ONE DEVELOPS OFF THE
OREGON COAST THE WINDS WILL SHIFT WESTERLY THROUGH THE DELTA AND
SOUTHERLY WEDNESDAY NIGHT FOR MOST SACRAMENTO VALLEY AREAS. AS
THAT SHORTWAVE ROTATES THROUGH ON THURSDAY IT WILL BRING THE BEST
CHANCE FOR SHOWERS OVER THE NORTHERN MOUNTAINS WHILE FURTHER SOUTH
THE SYSTEM STILL IS FAIRLY MOISTURE STARVED SO NO SHOWERS ARE
EXPECTED.
.EXTENDED DISCUSSION (SATURDAY THROUGH TUESDAY)
A MEAN TROUGH WILL LINGER OVER THE WEST COAST THROUGH THE WEEKEND
AND INTO THE FIRST PART OF NEXT WEEK. SEVERAL WEAK DISTURBANCES
WILL MOVE THROUGH THE LONGWAVE TROUGH AND BRUSH FAR NORTHERN
CALIFORNIA. MODELS ARE NOT IN AGREEMENT HOWEVER WITH THE
AMPLITUDE AND TIMING OF THESE FEATURES. THE ECMWF SOLUTION HAS
THE LEAST IMPACT FOR US AS IT IS LESS AMPLIFIED WITH THE LONGWAVE
TROUGH AND CONSEQUENTLY KEEPS OUR AREA DRY THROUGH THE PERIOD.
THE GFS AND GEM MEANWHILE HAVE COMPACT SHORTWAVES MOVING THROUGH
SATURDAY NIGHT AND MONDAY NIGHT...WITH LINGERING MOUNTAIN SHOWERS
IN-BETWEEN. THE GFS IS EVEN SHOWING SOME CHANCE OF CONVECTION
SATURDAY NIGHT FOR THE COASTAL MOUNTAINS AND LASSEN VICINITY. WITH
LIMITED CERTAINTY...HAVE OPTED FOR A SLIGHT CHANCE OF SHOWERS
THROUGH THE PERIOD OVER THE MOUNTAINS FROM AROUND RED BLUFF
NORTHWARD. HAVE ADDED A MENTION OF THUNDER SAT AFTERNOON/EVENING
TO ACCOUNT FOR SFC-BASED INSTABILITY PROGGED BY THE GFS...WHICH
ALSO HAPPENS TO MATCH UP WELL WITH NEIGHBORING FORECAST OFFICES.
REGARDLESS OF WHICH SOLUTION VERIFIES...THE ONLY IMPACT FOR THE
CENTRAL VALLEY WOULD BE CONTINUED SEASONAL TEMPERATURES WITH
ONSHORE FLOW AND A FEW CLOUDS. -DVC
&&
.AVIATION...
VFR CONDITIONS CONTINUE NEXT 24 HOURS FOR INTERIOR NORCAL TAF
SITES. A LOW PRESSURE SYSTEM BRUSHING NORCAL TO THE NORTH WILL
SHIFT CENTRAL VALLEY WINDS TO THE NORTH OVERNIGHT AROUND 10KTS
AND BRING SOME MID-LEVEL CLOUDS BY WEDNESDAY AFTERNOON. -DVC
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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